cleaning, pretreatment & surface preparation

CHOOSING THE RIGHT CLEANING EQUIPMENT VENDORS

BARBARA KANEGSBERG AND ED KANEGSBERG, BFK SOLUTIONS LLC,

PASADENA, CALIF.

The power! New process equipment provides a rush that is pretty much likewhat happens when you drive a new car off the lot. New cleaning process equipmentbrings the promise of manufacturing bright, shiny, great-looking productthat will meet all the specs, that will show a high yield, and that your customerswill love. How do you find that equipment? Depending on the capital outlay,you may do a few Web searches, go to some trade shows, grow a meadow ofcatalogues around your desk, talk to more than a few sales reps, and even dosome site visits. Too much of the information available falls along the line of“don’t worry, it’s the best, lots of people use it.” How do you find reliable, comparativeinformation. How do you make a decision? Do you throw a dart at thecatalogues and see where it lands? Do you pick cleaning equipment in a colorthat matches the décor of the fab? We’ve actually seen that happen.

Get the facts

Improving a cleaning process, setting up a new process, replacing outdatedequipment – all these activities involve decisions that can make or break thequality of surface finish, that can make or break your manufacturing business.Cleaning is a process that typically meshes one or more chemicals with cleaningequipment. Vendors and distributors are eager to extol the benefits of their products.Here are a few tips to get you started in working with vendors productivelywhile avoiding pitfalls of sales hype. These include six questions to ask cleaningequipment suppliers.

Talk to yourself

Before you start tracking down new cleaning equipment, before you lookthrough catalogues or talk to reps, start by asking yourself the following question:exactly why are you considering new cleaning equipment?Look at your current cleaning process. Ask the workers – the people who actuallyhave to run the process day in and day out – what they like or don’t like. Thismay take a (groan) little tact and diplomacy, because sometimes people answerin the extreme. “It’s fine,” may actually mean “don’t bother me; I’m used to thissystem and don’t want to change; I won’t speak up because I don’t want to getfired; I actually have an older cleaning system out back and I don’t want to tellyou.” “It’s terrible,” could translate to “I actually have to do the maintenanceon this thing; and I hate it.”Then, ask yourself how will new cleaning equipment make your life easier?What are your expectations? Is the problem acute? For example, is the currentequipment not cleaning effectively? If so, check to see if something has changed,something that could perhaps be fixed without purchasing new equipment. Has

the cleaning chemistry changed? Is simple maintenance required? On the otherhand, if cleaning chemistry is spewing euphorically out of your classic “midcenturymodern” equipment and onto the plant floor, if your repair person ison speed dial, perhaps it is time for an update.

Resist making an immediate, uninformed decision. If necessary, lease theequipment, with an option to buy; or use a good contract cleaning house. Evenbetter, start investigating new cleaning equipment while your current processis still functional.

What if you don’t have a production process? Some start-up companiesput off even investigating manufacturing processes on the grounds that theymight sell the company (or at least the idea for the product). Such companiesmay limp along using glass stirrers, lab wipes, and elbow grease provided bysummer interns. Especially if the new product has very different characteristicsfrom existing ones, part of what makes it sellable is a sense that the start-upcompany has considered the concept of manufacturability. Therefore, if youhave a prototype process, it’s a good idea to look at cleaning options and evento set up a prototype production line, whether or not the company ever actuallyproduces the product.

Six Questions

Let’s get started. Here are six questions to ask the rep (or you could Web search orlook through the catalogues – sometimes it’s more effective to ask); we summarizethem in Table 1. They are not the only questions to ask; they will provide a startingpoint; and they may allow you to eliminate options that won’t do the job for you.

1 - What kind of cleaning equipment is it?

It’s tempting to buy a system based on overall, outward appearance. All cleaningsystems have features and limitations. Enthusiastic reps may honestly believethat their cleaning system will work for your process. Judge for yourself.An in-line conveyor belt cleaning system may be perfect for some applications.However, a spray cabinet might be better in situations where a few largeparts are being cleaned at a time. Very small parts might have to be individuallyfixtured – this takes time. A vapor degreaser might be the best answer if you areconsidering only solvent cleaning; or if soils aren’t being successfully removedwith water. Keep the options open. An ultrasonic system could allow you to useaqueous (water-based) cleaners; ultrasonics may be needed with solvents as well.

2 - How does it work?

Let’s first review the basic concept of the cleaning process. Cleaning is removingsoil, matter out of place, things that, if left on the part, will interfere withplating, other coating, or final assembly. A complete cleaning process includeswashing, rinsing, and drying (Table 2). With some exceptions, effective cleaninginvolves the cleaning agent (chemistry), cleaning forces, temperature, and time.Washing is the first step. Washing removes the soil from the part and keepsit away from the part. Because the cleaning agent (the chemistry) can itself leaveresidue, a rinse step is often (but not always) needed. Rinsing can continue thewashing action; however, the primary purpose, particularly in aqueous andsemi-aqueous processes, is to remove the cleaning agent. The drying step canalso continue the washing action; the primary purpose is to remove water orsolvent. All of these steps have to be accomplished without damaging the partsor inadvertently recontaminating the parts.

Is the process you are contemplating actually a cleaning process? Anodic orcathodic processes are often thought of as cleaning; and, in the sense that theyremove unwanted material from the surface, there is a kind of cleaning function.However, electropolishing may not be a complete or sufficient cleaningprocess. If other soils are not removed first, there can be interference; it maybe necessary to begin with a true wash/rinse/dry process. Be on the lookoutfor other processes, like passivation and heat treatment, that may not be truecleaning processes.

Consider what sorts of cleaning forces are needed. Applying force can movethe soil away from the surface. Will ultrasonic cleaning help the process? Evensolvent-based cleaning can benefit from ultrasonics. There are many variablesand, therefore, many choices in ultrasonics (1). Don’t assume ultrasonics cleaningis a magic bullet. Test ultrasonics in your process for effectiveness and forthe potential for product deformation and surface damage. The same holds truefor other sorts of cleaning action, like spray and turbulation. Styles in cleaningchange; and the assertion that “everyone buys this great cleaning system” doesn’tmean that it’s right for you.Does the equipment being offered have rinsing and drying capabilities? Arethose capabilities adequate for your current and near-future product line? If youneed rinsing, resist the temptation to purchase an inexpensive washing systemwhere the rep tells you that you can “always add a rinse tank.” It probably won’thappen.

Some newer cleaning agents have high boiling temperatures; and, if they arenot rinsed, can leave a residue that does not readily evaporate and interfereswith coating. Often, a single wash tank needs to be followed by at least two rinsetanks. A reverse cascade pattern, where water moves from the final rinse to thefirst rinse, can provide for more effective, efficient water usage. We see too manyinstances where the rinse tanks are static dip tanks that rapidly fill with cleaningchemistry. They wind up functioning as wash tanks; rinsing is not taking place.Then, there is drying – the orphan step in the cleaning process. This is the stepwhere the budget runs out; and too many people buy into the delusion that drying

equipment is not really necessary. Then, they find that it is necessary; partsbecome recontaminated or they corrode. It is possible to add drying equipmentlater on. However, first comes the battle with the bean counters. Also, achievinga seamless, effective cleaning process will be more difficult.Consider recycling. Recycling, reuse, and closed-loop systems have traditionallybeen thought of as politically correct concepts – activities that would be niceto do, if only we had the money. However, consider the quality and economicimplications of recycling and closed-loop systems. Water treatment and disposalcosts are high. Cleaning chemicals cost money. It is often cost-effective to restoreand reuse the cleaning agent and rinsing fluids. In addition to saving money indisposal costs, on-board recycling can result in more consistent chemical quality

and can contribute to higher yield.

3 – What cleaning chemicals can I use?

This is rather a loaded question; particularly because we are considering thecleaning equipment. We could write a totally separate article about questions toask the cleaning agent vendor. Choosing the right cleaning chemistry is a crucialpart of selecting the cleaning process (2,3).

Consider the choice of cleaning agent in parallel with the choice of cleaningequipment. Linear thinking takes too long and costs too much money. There aremany types of cleaning agents, broadly categorized as aqueous, semi-aqueous,co-solvent, and solvent. Even so-called solvent free processes use chemicals likesteam, CO2, and the numerous chemicals species generated in plasma systems.

Understanding cleaning agents is a separate topic, with specific questions forcleaning agent vendors. Some factors include how well the cleaning agent performs,the potential to damage the product, initial costs, process costs, whetheror not it can be filtered or distilled, how long it lasts, waste management costs,and safety and/or environmental regulatory constraints.Just as there is no universal cleaning agent or universal solvent, there is nouniversal cleaning system. Some systems are more flexible than others; and youmay not want to put all your eggs in one basket. It is important to determinewhat sorts of cleaning agents “work” in a given cleaning system. An answer thatthe system can always be adapted is not enough. Sometimes, if the cleaningchemistry is changed, seals have to be changed; or different filters may be needed.The operational temperature range for the equipment may not be optimal forother cleaning agents under considerations.Trust but verify. Demonstrate that the process works with the chemical inquestion. Beyond cleaning well and not damaging the product, understand

the safety and environmental regulatory hurdles. Sometimes, the equipmentcompany may not be aware of the safety and regulatory issues involved witha particular chemical. Some chemicals require low flashpoint systems or theyoxidize to form flammable or combustible compounds. In other instances anddepending on your regulatory microclimate, there are worker safety or environmentalregulatory issues that require solvent containment, monitoring, permitting,or waste management. If the equipment vendor is unaware of these issues,is unwilling to work with regulatory agencies, or – even worse – shows disdainfor regulatory agencies, beware!

4 - What’s the throughput?

How many parts can be cleaned per day? How long is each run, including dryingand cool-down time? If you are accustomed to a 2 to 5 minute solvent processin an open-top degreaser, be aware that, depending on the parts and soils tobe removed, an airless or airtight system can take 30 minutes or more per run.There are formulas to determine throughput; and reps can often provide estimates.

How long does the process actually take? Follow up to refine the estimateand include factors specific to your manufacturing requirements. If the vendorprovides an estimate of throughput, check both the math and the assumptionsbehind the math. For example, if throughput is estimated at 50,000 parts per8-hour shift; but you know you have to clean 25,000 parts during a specifictwo-hour period, a process that accounts for the “bump” in throughput willbe needed.In addition, given the sticker shock involved in pricing new cleaning equipment,throughput may be estimated a bit optimistically. You may hear commentslike “well, the process time is 30 minutes, but most of our customers saythey need less time.” Well, maybe – but are the parts clean enough? Even withautomated equipment, if parts have to be fixtured, loaded, unloaded, and perhapsallowed to cool, all those factors should be factored into the throughputestimate. Automated equipment may require the participation of assemblers;

and people need lunches and take breaks.Determine the frequency and complexity of routine maintenance. What happens

at the beginning of the workday? For example, ultrasonic systems have tobe degassed and often must be heated.

Your estimates of throughput should include room for growth (businesscould get better!); and a bit of wiggle room for process uncertainty. We see theunfortunate consequences of underestimating throughput. With insufficientcapacity, operators overload cleaning tanks; and they may short-change the processtime; this means cleaning will not be effective. Overloading can also stressthe cleaning system; this leads to more breakdowns and more repairs.Buying cleaning equipment with inadequate throughput will compromisethe entire surface prep and surface finishing operation. Visualize how the cleaningequipment will be used in your facility. Even better: observe a system underactual manufacturing conditions.

5 - Can you tell me about sizing, dimensions?

The product has to fit into the cleaning equipment. At the same time, largerprocess baths cost more money. There are ways to compromise. If 98% of theproduct can be in small- to medium-sized tanks, it may be better to purchase asmaller system and make other arrangements for the larger parts that show upa few times a year.The cleaning equipment has to fit into your facility. Obtain the overall dimensions;and this means all three dimensions; and it includes the maximum heightneeded for operating hoists. Will the equipment fit into the workspace? Are theceilingshigh enough? Can you get the cleaning equipment through the door?Ask the facilities department to provide actual measurements; “sure, we can doit” is not an actual measurement. How much space are you allowing? Is thereroom to load and unload product? Is there space to do routine maintenance?

6 - How much does it cost?

While this is the final question on our abbreviated list, it is one to ask severaltimes in the process. Early on, ask for what is sometimes gently referred to as abudgetary estimate. This term is a euphemism for “how close will the boss cometo a heart attack if I try to buy the equipment.” The company budget can limityour choices. If the cleaning technology you want costs half a million, and theboss has generously allocated up $30,000, a reality check is needed.Particularly for larger items, it’s a good idea to get multiple estimates. Toget realistic estimates, take the time for interchanges with the reps; walk themthrough the production area; listen to their sales pitches; ask questions. Inaddition, work with your process team and advisors to determine what featureswould most improve production. We typically see a wide range in vendor estimates.The estimates and the options suggested can be an indication of the vendor’sunderstanding of your process and also of likely support down the road.Keep in mind that capital equipment costs tell only part of the story. In Table1, we list other cost factors to be considered, including facilities considerations,installation, education/training, and ongoing process costs. Chemicals, replacementparts, routine maintenance, and disposables like filters (and the costsresulting from properly disposing of the disposables), all have to be factoredin. Chemical costs can be misleading. An expensive cleaning agent that cleanseffectively and that can be recycled or redistilled may last for years. An inexpensiveaqueous formulation that must be used at, say, a 1:4 dilution and must bereplaced weekly may not be a bargain compared with a second product thatcould be used at a 1:10 dilution and lasts for two months. Even with very ruggedcleaning equipment, repair and replacement is needed. Look for the weaklinks in the chain. What parts are likely to need replacement? What’s the meantime between repair/replace? How long does it take to get replacementparts?Depending on where the equipment is made, the availability of replacement

parts can be an issue. Purchasing a “kit” of replacement parts may be cheapinsurance.Ongoing support by the cleaning equipment vendor can save money. Thissupport begins at the employee training/education stage. Many newer cleaningsystems require instruction. Some vendors charge for training. Resist the temptationto pass on the training option. However, charging for initial training isnot a promising indication of ongoing vendor support.

Question to ask yourself again: why are you buying new cleaning equipment?

What do you actually need?

During the equipment search, review the initial question, the one you yourselfhave to answer. Why are you buying new cleaning equipment? Reviewing thegoals of the project will keep you focused on what is most of value. That meansyou buy quality equipment – but you purchase exactly what you need.As we mentioned, you may find that the current cleaning equipment can beoptimized to meet current production requirements – you don’t actually needto make the capital investment. Even if that happens, it is still worthwhile to dothe search, because it allows for a more informed decision.

The Decision

Surface prep is a critical cleaning process. Critical cleaning is not “cleanroomcleaning;” it’s doing the right amount of cleaning at the right point in theprocess.Are you ready to choose the best cleaning equipment after asking sixquestions? Maybe not; you will probably develop additional questions. Askingthe right questions involves understanding cleaning. There are many resourcesto help you ask the right questions. Will you know all the variables? It’s highlyunlikely; so at a certain point, preferably not during a process emergency,pull the information together, and make the decision. You will see moreeffective cleaning, and more efficient production. It’s just good business toclean it right.

Question Examples Follow up

1 - What kind of cleaning

equipment is it?

Dip tank, in-line,

sink-on-a-drum, spray

cabinet, dishwasher,

vapor degreaser,

airless/airtight system,

“non-chemical”(plasma)

• look at current cleaningequipment

• talk to the workers

• determine your process needs

• scope out company constraints

2 - How does it work?Wash/rinse dry versus

Wash only, cleaningaction (spray, ultrasonics,agitation, immersion,electrocleaning,temperature range)

• look at soil removalrequirements

• is the cleaning actionof the type you’ll need?

3 - What cleaning

chemicals can I use?

Water only, aqueous,semi-aqueous, solventblends, solvents

• consider company policy andregulatory constraints

• determine how fl exible thecleaning equipment will be –what types of cleaning agentscan be used

• test the system with your

product line - is it effective?

Does it cause product damage?

Table 1. Six Questions to Ask Vendors about Cleaning Equipment (continued)

Question Examples Follow up

4 - What’s the

throughput?

• typical process time

• start-up time

• refi ne estimates to refl ect yourmanufacturing reality

• consider “bumps” inproduction requirements

• allow room for productiongrowth

5 - Can you tell me about

sizing, dimensions?

• tank size

• overall dimensions

• are the tanks large enough?

• could a few larger parts becleaned separately

• will the equipment fi t throughthe door?

• are the ceilings high enough?

• is there room for operators tomove around the equipment?

• is there room for convenientmaintenance and repair?

6 - How much does it

cost?

• Base price

• fully “loaded”

• installation

• training/education

• maintenance

• which equipment upgradesdo you actually need?

• what facilities changes will beneeded (eg. water, power)?

• what are the ongoing processcosts?

• what are the energy costs?

• what treatment and wastedisposal costs are involved?

• are there permitting costs?

• will the equipment manufacturertrain the staff? Does it costextra?

• how much do replacement

parts costs? What’s the lead

time to get replacement parts?

Table 1. Six Questions to Ask Vendors about Cleaning Equipment (continued)

Step Functions

Wash (or clean) Remove soils from the part

Keep soils away from the part

Protect product surfaces

Minimize product damage

Rinse Continue cleaning action

Remove cleaning agent residue

Protect product surfaces (including rust preventative)

Minimize product damage

Dry Continue cleaning action

Remove water or solvent

Minimize product damage

Table 2. Cleaning process steps

REFERENCES

1. Barbara Kanegsberg and Ed Kanegsberg, “Troubleshooting Your UltrasonicCleaning Process,”Metal Finishing Magazine, September, 2009.

2. Barbara Kanegsberg, “Cleaning Agents: Overview,” in “Handbook for CriticalCleaning, Cleaning Agents and Systems,” Volume 1, B. and E. Kanegsberg, ed,CRC Press/Taylor & Francis, 2011.

3. Michael Beeks and David Keller, “Aqueous Cleaning Essentials,” in“Handbook for Critical Cleaning, Cleaning Agents and Systems,” Volume 1,B. and E. Kanegsberg, ed, CRC Press/Taylor & Francis, 2011.

4. Barbara Kanegsberg. “Evaluating, Choosing, and Implementing the Process:How to Get Vendors to Work with You,” in “Handbook for Critical Cleaning,Applications, Processes and Controls,” Volume 2, B. and E. Kanegsberg, ed,CRC Press/Taylor & Francis, 2011.

5. Arthur Gillman, “Blunders, Disasters, Horror Stories, and Mistakes You CanAvoid,” in “Handbook for Critical Cleaning, Applications, Processes andControls,” Volume 2, B. and E. Kanegsberg, ed, CRC Press/Taylor & Francis,2011.

6. John Durkee, “Don’t Become an Endangered Species, Buy the Right CleaningEquipment,”Metal Finishing Magazine, September, 2004.

ABOUT THE AUTHORS

Barbara Kanegsberg and Ed Kanegsberg (the Cleaning Lady and the Rocket Scientist)are experienced consultants and educators in critical and precision cleaning, surfacepreparation, and contamination control. Their diverse projects include medical device

manufacturing, microelectronics, optics, and aerospace. Contact:این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید

finishing equipment & plant engineering

FINISHING SYSTEM EFFICIENCY

UPGRADES FOR A CAPITALCONSTRAINED

MARKET

BY TIMOTHY KURCZ, DIRECTOR OF SALES, JESSUP ENGINEERING,

ROCHESTER HILLS, MICH.

During this furtive economic recovery, captive and independent finishers facethe need to increase capacity, improve quality, and reduce resource consumptionas rising production volumes stretch a downsized industrial base. This challengeis the result of wholesale market consolidation and continued global competitivepressure. Unfortunately, recently imposed government banking controls limitcapital availability and the option to purchase new machinery no matter howstrong the business case.With many new installations out of the picture for the short term, the toooftenemployed lowest cost solution is simply to increase demand on alreadystressed human/machine resources. This is risky given the operator-sensitivenature of the finishing business and finicky, well-worn machines. A better choiceis targeted investment of carefully engineered upgrades designed to enhanceexisting plating, anodizing, coating, and other types of finishing systems.Jessup Engineering,1 known as a leading manufacturer of programmablehoists and turnkey finishing systems, responded to customer demand for costeffective,incremental machine improvements. Every customer installationrequires careful analysis to fully understand, engineer, and prioritize improvementopportunity. Partnership work teams establish targets, and the customerselects the most cost-effective solution for each machine. Over the past year, thefollowing upgrades achieved specific productivity goals for Jessup customers’existing plant and equipment.

1) An intuitive touch screen industrial personal computer/humanmachine interface (PC/HMI) is the heart of every Jessup controlsupgrade (Figure 1). Available with single-touch toggled bilingual languageformat, it displays system overviews, recipe options, hoist programming, load/unload monitoring, process functions, load tracking,fault diagnostics, and pre-programmed maintenance schedules. Forconvenience, it also includes imbedded drawings, schematics, operationsmanuals, and spare parts lists. Control features include monitoringand control of hoist equipment, process tanks, and accessory equipment.Quick scan input devices may include bar code or radio frequencyidentification (RFID) technology. PC-controlled programmable logiccontroller (PC/PLC) systems provide load-by-load output data in asimple comma separated variable file (CSV) format for interface withcustomer quality and business management systems through Ethernetcommunications. Performance monitoring includes shift reports fortotal time and cycles, automatic vs. manual operation, load/unloaddelay, and fault data. To speed correction of unexpected stoppages, the control system provides automatic system diagnostics. Detailed screen

؟؟؟

Figure 1. Jessup PC/HMI operator screen image

???

Figure 2. Jessup rectifier control screen.

???

Figure 3. Jessup chemical feed control screen.

???

Figure 4. Jessup rinse water management screen.

display fault location and actions needed to quickly restore production.Internet-based remote monitoring expedites troubleshooting and repairs.Specific screen pages may include:

a) System overview, including hoists, tanks, carriers, etc.

b) Alarm history provides a view of recent alarm information.

c) Hoist programming requires no programmer or special devices.

d) Machine diagnostics provides detailed faultinformation.

e) Service reminder recommends maintenanceprocedures.

f) System security requires login and password for access.

g) Shift report provides machine performance data.

؟؟؟

Figure 8. Jessup cylindrical vs. hex barrel comparison.

k) Bar code or keypad interface for recipe input.

l) Load-by-load data capture, storage, and export.Except in cases where simple fixed process cycles run, or where machine

management and data recording is unnecessary, PC/HMI operation of finishingsystems is standard for all new machines. Retrofits are easily accomplished.They often include machine position sensors, rinse water control systems, andprogrammable chemical feed pumps. Machine monitoring, management, loadby-load data recording and paperless quality management features offer quick

return of customer investment

2) Programmable, recipe-based individual cell rectification enables precise,repeatable plating thickness for every load regardless of part count forrack plating, or weight for barrel plating operations (Figure 2). ThisPC-driven feature derives and calculates surface area data from a customer-supplied lookup table on a discreet part number basis. Operatorentered load data assures precise amp square foot (ASF) delivery for rackplating systems. Barrel weight is verified directly by load cells by eitheraddition or subtraction methods. This assures correct ASF delivery forbarrel plating systems. Installation of individual rectifiers integratedwith a PC/HMI recipe-driven controls make over- and under-plating a

3) Programmable chemistry replenishment reduces operator workload andimproves quality by reducing fluctuations in process baths. This recipedrivenfeature assures precise additions based on PC-tracked productioninformation. The goal is to dampen the bath concentration saw-tootheffect common with manual addition practices. Precision control is availableonly by an integrated PC/HMI. The control screen allows external adjustment of replenishment volumes at any time during machine opera-distant memorytion (Figure 3). Installation of PC/HMI-driven chemistry managementcontrols will improve quality and reduce operator addition errors.

4) Programmable load-by-load rinse water replenishment allows optimizationof water consumption on an individual part number basis.This feature enables experimentation with the minimum rinse watervolume necessary to assure quality processing. The goal is to minimizetotal rinse water usage, thus reducing wastewater treatment volumeand associated chemistry consumption. Precision control is availableonly by an integrated PC/HMI. The control screen allows separatereplenishment volumes for full or empty loads, further minimizingrinse water usage (Figure 4). Installation of PC/HMI recipe-drivenrinse water controls will immediately reduce rinse water consumptioncompared to constant flow rinse water replenishment systems.

5) Variable plate time programming for multi-process machines allowsmultiple immersion times and cycle options while maintaining repeatableprocess parameters. Production rate remains fixed to take bestadvantage of material handling equipment. The Jessup variable platingtime process accepts work with differing plating tank immersiontimes while retaining predictable and repeatable process times in other areas of the machine (Figure 5). Immersion times are a multipleof the machine cycle time. This approach guarantees repeatable plating at a constant production rate. Load/unload operations andexternal logistics remain unaffected. Also available is process cyclere-engineering to speed changeover between processes. This becomesincreasingly important as the industry shifts to smaller lots, whichrequire more frequent break-in sequences. Retrofit hoists, controls,and variable plate time programming eliminate guesswork and operatorsensitivity associated with older simple-cycle multi-process finishingsystems.

6) NADCAP & ISO quality system capable automation is assured withPC/HMI over-the-top and appropriate sensor technology monitors,controls, and records critical quality control information. Data suchas tank temperatures, immersion times, rectification, pH, conductivity,barrel rotation or oscillation speed and/or duration, chemistryadditions, and rinse water usage is collected and stored on a load-byloadbasis. Further, data is exported to the customer data highway forupload into quality management database. This system creates trulypaperless quality control. The Jessup PC/HMI system captures moredata than end-user customers require. The finisher’s quality controldepartment will have access to current and historical trend data neverbefore available.

7) Jessup cylindrical barrels can offer 17% increased capacity and 12%better work-to-anode relationship compared to hex barrels for moreproductive plating. More consistent anode-to-work relationshipimproves plating efficiency (Table 1). The drawing and comparisonchart clearly illustrate capacity and work-to-anode differences. Jessupplating barrel design features include: a one-piece cylindrical shell;tongue-and-groove, double-welded construction; integrated, heatfusedtumbling ribs; CNC drilled or slotted perforation patterns forshorter drain dwells; and knob or quick-change inside-out style loadlockercovers (Figures 7 & 8). A machine specific tab-lock design isalso available for Jessup robotic cover handling systems used for fullyautomated bulk load/unload systems.Jessup cylindrical barrels retrofitted to your plating line can deliver17% more production with no other machine changes compared tohex barrels. The example 60-inch-wide barrels fit an identical workspaceanode. Run at 12 loads per hour (LPH), the Jessup barrel delivers

8.16 more cubic feet. At 20 hours per day, this equates to 163.2 morecubic feet. If this machine runs 240 days per year, the difference is anincredible 39,168 cubic feet more production delivered on an annualbasis by installing Jessup barrels!Jessup barrels are also available with center partitions, enabling largemachines to process smaller lot sizes. This feature assures optimummachine utilization and maintains critical workload separation when combined with divided load/unload systems. PC over-the-top controlstrack, record, and export separate data for part numbers run simultaneouslyto a customer data highway for paperless quality controlmanagement and reporting. Partitioned barrels add small lot flexibilityto large capacity machines.

8) The Jessup single-point set-down superstructure design incorporatesfixed drive gear engagement (Figure 9). This eliminates ratchetingassociated with designs using adjustable gear mesh. It also reduceswear and tear on motors, drives, and associated components by eliminatingsuperstructure rock common to multi-point set-down designs.Delicate parts suffer from one-process-fits-all rotation management.

Recipe-driven control of barrel rotation and/or oscillation with a PC/HMI enables gentler treatment of sensitive parts (Figure 10). If newbarrels and superstructures are part of a customer upgrade plan, thesingle-point set-down design and individual barrel control is a welcomeimprovement when integrated along with new drives and saddles.

9) Hoist-mounted barrel drives engage in the up position, allowingbarrel rotation during the process cycle (Figure 11). Programmablespeed and duration dramatically reduce drag-out induced carry overby draining work directly over the process tank. This feature is especiallyimportant for parts known to cup solution. PC/HMI controlledup rotation combined with rinse water management reduces waterconsumption, waste treatment, and chemistry usage. Up-barrel rotationis mandatory for critical resource reduction needed in today’shighly competitive finishing environment.

10) Hoist and motion control upgrades such as high efficiency VFDcontrolled Energy Star-rated Eurodrive motor/drive combinationsfor electrical energy savings. Smooth-operating, corrosion-proof beltlift conversions replace older wound wire cables. This dramaticallyextends hoist lift maintenance intervals. Full-length, non-contactabsolute linear encoders allow faster hoist operation with smoothermotion profiles eliminating rack or barrel shake (Figure 12).Together they improve machine productivity and operator safety.Finally, extremely durable overhead cat-track wire ways eliminatethe more sensitive exposed festooning umbilical cables. Multiplehoist improvements reduce energy consumption and create faster,smoother motions, thereby reducing wear and improving safety forfinishing systems

CONCLUSION

If your company is capital constrained for any reason, the best option toremain competitive is to improve existing equipment incrementally until theeconomy supports a new machine purchase. Clearly, there are many optionsavailable for older finishing systems. Whether load/unload equipment, newcontrols, or hoist automation, Jessup offers productivity improvements pricedto fit any budget.

REFERENCES

1. Jessup Engineering formed in 1971 to manufacture automated hoistsystems for the metal finishing industry. Over the past 39 years, customerdemand drove Jessup to become a turnkey finishing system provider,delivering hoist automation, system components, and peripheralaccessories. With more than 630 systems incorporating 1,250 hoistsand countless conversions installed, the Jessup team has the experienceneeded to integrate an ever-increasing array of mechanical, hydraulic,electric, and electronic upgrade components. We believe in a long-termcustomer focus and support, exacting quality, and on time start-up.In-house mechanical, electrical, controls, parts and service support originatesfrom our Rochester Hills, Mich., location. To learn more aboutJessup Engineering products and services, go to www.jessupengineering.com or call to schedule a visit.

ABOUT THE AUTHOR

Timothy J. Kurcz, director of sales for Jessup Engineering, is also responsible for market andproduct development. A member of the surface engineering community for more than 33years, his experience includes process automation for adhesives, sealants, coatings, electrolyticand electroless plating, fluorescent penetrant inspection, cleaning, passivation, dip-spin,electrocoat, and autophoretic paint coatings. Kurcz can be reached at (248) 853-5600 or via

e-mail at این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید

Equipment

coating materials and application methods

POWDER COATING EQUIPMENT

BY NICHOLAS P. LIBERTO

POWDER COATING CONSULTANTS DIV. OF NINAN INC., BRIDGEPORT, CONN.

There are many ways to apply powder coating materials; however, the materialthat is to be applied must be of a compatible type. For instance, if the applicationmethod is fluidized bed, the powder coating material must be a fluidized bedgrade. Conversely, if the method of application is electrostatic spray, the powdermaterial must be an electrostatic spray grade.Once the material is correctly selected, the application method is chosen bypart design and production goals. There are two forms of application methods:fluidized bed application and spray application. These vary as widely as theapplications they suit.

FLUIDIZED BED

This application method was the first one used to apply powder coating materials.It is still used on many applications where the cured-film thickness is above5.0 mils. Typical items are wire products, electrical bus bars, etc.The fluidized bed application method can be performed in two ways. One wayis the nonelectrostatic fluidized bed. This process requires preheating the partso that powder will melt and adhere to it. The hot part is placed into a fluidizedbed of powder for coating. The amount of powder that is applied to the partis a function of how hot the part is and how long it is in the bed. It should beobvious that tight film-thickness control is not of primary concern when thismethod is used, as the total coating thickness often exceeds 10 mils.To gain more control of film thickness on the part, with a fluidized bed system,the principles of electrostatics are introduced. As shown in Fig. 1, the part is transported above the fluidized bed and the powder is attracted to it. The partrequires no preheating prior to being placed above the bed. Powder is attractedto the part by an electrostatic charge on the powder particle. This electrostaticcharge is developed in an electrostatic field either above or in the fluidized bed.Film thickness on the part now is controlled within tighter tolerances notonly by the amount of time the part is in the fluidized bed but also accordingto how much electrostatic charge is on the powder particle. Sometimes, heatstill is used in this process to overcome Faraday cage problems caused by partconfiguration. This process routinely applies powder from 5 to 10 mils thick.Electrostatic fluid bed application is used for coating electrical motor armatures.These require a high dielectric strength coating with close film-thicknesscontrol to allow the wire to be wound properly.

SPRAY APPLICATION

Applying powder coating with electrostatic spray equipment is broken downinto two types. In each case electrostatics must be used to attract powder to thepart. There is no mechanical attraction or adhesion to hold powder to the partas seen in liquid spray systems. The two types of electrostatic spray equipmentare corona-charged spray guns and tribo-charged spray guns.

Corona Guns

This device uses an electrostatic generator to create an electrostatic field betweenthe gun and a grounded part. Powder is sprayed through the field, picks up anelectrostatic charge, and is attracted to the part. The amount of charge thatis transferred on the surface of the powder is a function of electrostatic fieldstrength and the amount of time the powder particle is in the field. Also ofimportance is the surface area of the powder particle, as finer powder particleshold less electrostatic charge. The following equations (see Fig. 2) best explainhow the powder is charged:

Field Strength: E=V/d

Charge on Particle: Q= 1/2 CEt2

Notice that some factors are more important that others. For instance, electrostaticfield strength is directly proportional to applicator electrode voltage.Also, the distance between the part and the applicator (sometimes called thetarget distance) will directly affect electrostatic field strength.The charge on the powder particle (which causes the attraction) is most affectedby the amount of time the particle is in the field (by its square). The time andfield strength will determine how much powder is attracted to the part (i.e., firstpass transfer efficiency). The time the powder particle is within the electrostaticfield is most easily controlled by adjusting the velocity of the powder pumpedthrough the gun, or applicator, and reducing the speed of the applicator motion.It is a known fact that systems that use reduced powder velocity and slow gunmotion will provide the best coating efficiency with the least effort.The powder coating process is most often used to apply a charged dielectricmaterial (powder coating) and onto a conductive (grounded) part. However,electrostatic powder coating on nonconductive materials (i.e. plastics, rubber,glass, etc.) can be performed using a conductive primer or aiding powder attractionby heating the surface to be coated. Additionally, electrostatic charging ofconductive materials (i.e., blended metallic powders) can be difficult since theycan short-circuit theapplicator’s charging circuit. However, most equipmentmanufacturers provide electrodes outside the powder path to overcome thisproblem.Both positive and negative polarity electrostatic guns are available frommost manufacturers to provide efficient charging of widely divergent coatingmaterials. It is worth noting that 98% of all applicators used in powder coatingoperations are negative polarity devices.Code requirements insist that certain protection circuits be part of the system.Among these are current limitation to control arcing and grounding of all equipmentand products that are coated to dissipate stored charges. System interlocksare required for automaticequipment. Guidelines for this equipment are listedin National Fire Protection Association Code (NFPA) 33.

Tribo Guns

Tribo-charged spray equipment uses the principle of frictional electrostaticcharging. This type of charging is best explained by the following analogy: Whenyou shuffle your shoes on a carpet in the winter, you create an electrostaticcharge that is stored in your body. This charge is usually dissipated when youcome into contact with a ground, such as a light switch. This phenomenon willonly occur in a dry (not humid) environment. This is why we are not botheredby static electricity in the humid summertime, but only in the dry air of winter.Tribo-charge spray equipment will direct the powder stream through a paththat it will tumble and rub against a dielectric surface within the applicator,yielding a frictional electrostatic charge on the powder particle. This path isaccomplished by lengthening the powder route through the spray equipment ineither a straight, radial, or oscillating path. The amount of electrostatic chargethat builds up on the surface of the powder particle is a function of several variables,including (1) the amount of time the powder particle is subjected to thefrictional charging apparatus; (2) surface area of the powder particle; (3) drynessof air the powder is transported with or comes into contact with; and (4) thetype of resin material from which the powder is made Controlling these variables is important to assure that the powder particle willbe properly charged. Remember: if the powder is not charged, it will not adhereto the part unless the part is hot enough for the powder to stick on contact.The amount of electrostatic charge that typically is developed by this apparatusis less than that produced by corona equipment. The polarity of the tribocharge is a function of the material being sprayed and the material that it isrubbed against. If the same two materials are used, the polarity will always bethe same.Tribo-charge applicators can often be used to overcome Faraday areas ondifficult-to-coat parts, as there is no electrostatic field used to charge the powder.This flexibility, however, is often overshadowed by the additional processand coating materials controls that are required to ensure successful coating.

Powder Bells

This device uses an air turbine to rotate a conical cup used to atomize thepowder coating. Powder is pumped to the cup where the rotational forces causecomplete powder atomization. The feed system used to support this device issimilar to that of spray guns. These devices employ the corona charging method,described earlier in this article.Powder bells are capable of dispersing a large quantity of powder coatingover a large area. Therefore, the typical applications for this device are large flatcomponents, such as appliances and automobile bodies.

POWDER DELIVERY

All spray application equipment requires a delivery system (see Fig. 3). This. delivery system consists of a feed hopper, a powder pump, and a powder feed hose.The feed hopper can be one of two types (see Fig. 4). The first type is called agravity feed hopper. As the name suggests, this feed hopper uses gravity to movepowder to the powder pump located at the bottom. This hopper usually is conicalin shape to funnel powder to the pump. Sometimes a mechanical stirrer orvibratory assist is used to maintain an even powder flow. Frequently, without amechanical assist, powder will bridge across the bottom of the funnel causinguneven feed to the pump. Since there is no air mixed with the powder in the hopper,this device is often employed when spraying blended metallic powders thatcan be stratified within a fluidized hopper.The second type of powder feed hopper uses a fluidized bed. It is the same as thefluidized bed system described previously. A compressed-air supply is connectedto the plenum chamber below the fluidizing plate. The fluidizing plate causes theair to fluff powder in the hopper to a state resembling water. Now the powder canbe drawn out by the powder pump. Since powder is mixed with compressed airfrom the plenum, the powder within this device is very homogeneous in nature.Powder pumps are mounted on the hopper and are connected to a pick-up tubeto draw powder out of the hopper. These pick-up tubes usually are positioned anappropriate distance into the fluidized bed to assure that the turbulence usuallypresent on the surface of the fluidized plate is not drawn up into the powderpump. This turbulence can cause inconsistent powder feed to the applicators.

Box Feeders

Powder equipment manufacturers also provide methods of pumping powdercoatings directly from their shipping containers (box or bag) to the spray gun.This method is called the box feeder and utilizes a tilted vibrating table to supportthe box of powder. A powder pump connected to a pick-up tube is insertedin the lowest portion of the box. A compressed air jet is employed at the end of this tube to assistpowder flow into the tube. Powder is then pumped directlyfrom the box to the spray gun without the need of a feed hopper. This approachmakes color change cleanup quick and easy, as only the pick-up tube, pump,and hose need to be cleaned. Changing the powder box completes the colorchange task.

PUMPS

Most powder pumps are designed to work by the venturi principle. Compressedair is directed perpendicular to the venturi pickup, causing a differential inpressure, or vacuum, that siphons powder out of the feed hopper or box feeder.When the powder enters the compressed air stream, it is pushed through thepowder hose toward the applicator. An additional compressed air supply isintroduced at the point where the powder enters this air stream (see Fig. 5) todilute the powder and increase its velocity. Increasing powder velocity ensuresthat the powder stays within the air stream as it proceeds through the hose,reducing surging or pulsing problems. Surging occurs when the powder lays atthe bottom of the hose until enough air pressure builds behind it to push it outwith a burst. Both air supplies have check valves to force the air to go throughthe powder hose, allowing independent control of both powder quantity andspeed through the feed hose.Powder hose can be made from several materials, including urethane, vinyl,and certain rubber compounds. Hose diameter and length are critical. Diameteris dictated by the powder pump used; it always should match the manufacturer’srecommendation. Length always should be as short as possible to reduce backpressure to the powder pump. This reduces surging of the powder stream to thegun. Avoid bends and kinks in the hose routing.The more powder you pump using venturi style pumps the faster it travelsthrough the electrostatic field. Consequently, transfer efficiency will be lowerat higher feed rates. Applications requiring highly controlled powder flow ata wide range of output rates use high density - low pressure (HDLP) powder pumps. These devices deliver a column of powder to the applicator withouthaving to mix it with compressed air. Reducing the compressed air within thepowder stream decreases the velocity of the powder delivered from the applicator,slowing powder speed, increasing powder density, and eliminating aerodynamicissues that may cause coating difficulties on box-shaped parts. Since thesepumps employ significantly smaller diameter feed hose, the hose is much easierto clean with compressed air purging, making these pump the preferred choicefor “fast color change” systems.

GUN MOTION

Automatic spray devices are often accompanied by some ancillary equipmentused to produce spray gun motion. Gun-motion equipment can be broken downinto four general categories: oscillators, reciprocators, multi-axis machines androbots.Each of these gun-motion systems has a different design and is used to fill aspecific coating requirement; however, all have one common feature. They aredesigned to move the spray gun(s) in one or more planes to coat a larger areathan a fixed spray gun. Thus, the number of spray guns required to coat a givenarea can be reduced. This makes for a more efficient and economical systemdesign

Oscillators & Wagglers

One type of gun-motion device is called an oscillator. This design is differentfrom other movers in that it usually has a fixed stroke and speed. Some unitshave adjustment of these parameters, but they cannot be used while the machineis running. The main component of this type of equipment is an eccentric wheeland lever as shown in Fig. 6. The motor rotates the eccentric wheel. The lever,which is attached to the wheel at some distance from the center, will translatethis rotary motion to a vertical motion.Stroke length is determined by the position at which the lever is attached tothe eccentric wheel and by the diameter of the wheel itself. It can be adjusted bylocating the lever at different points on the wheel radius. Speed is dictated bythe motor and gear reducer used in the design. Sometimes, there are clutchesand adjustable belt sheaves that will provide some speed adjustment; however,neither speed nor stroke adjustment can be changed while the unit is running.Wagglers (radial oscillators) pivot the gun through an arc, where straightoscillators provide vertical gun motion in a straight line. Gun-to-part targetdistance is affected with radial oscillators, while straight oscillators will nothave this problem.

Reciprocators

Reciprocators (see Fig. 6) use a variety of electronics to control both stroke andspeed. In these machines, the mechanical linkage between the motor and gunsis fixed; therefore, speed and stroke control must be adjusted electrically. Theseadjustments are sometimes made at the control panel and sometimes at theunit itself. For instance, stroke adjustment can be made by moving electricallimit switches in the unit or by adjusting an electronic feedback loop variablein the control panel.Speed control is accomplished by a variety of methods depending upon thetype of motor used. For instance, those designs that use a DC motor will providespeed control by varying voltage to the motor. Reciprocators that use AC motorshave variable speed-control circuits to adjust speed. Both types allow adjustmentduring operation. This offers some flexibility over the oscillator design whendifferent stroke lengths and speeds are required to coat different parts duringthe production cycle.

Multi-Axis Machines

Both oscillators and reciprocators provide movement in one plane only. Multiaxismachines were developed to provide increased coating flexibility and meeta demand for total automation. Multi-axis machines have been successful ineliminating some or all of the manual touch-up necessary on some products.Though costly, this increased automation often will pay for itself by providingconsistent part coating with minimal, if any, touch-up.The multi-axis machine design is made up of two or three reciprocators thatwill move the gun(s) in two or three planes. The convention used to label thethree axes of motion is as follows (see Fig. 7).

X = parallel to the conveyor travel

Y = up and down

Z = in and out

The design of these units is the same as reciprocators with respect to thecontrol of speed and stroke adjustment; however, because the units must trackparts moving along the conveyor, the addition of a programmable logic controller(PLC) is required.The PLC will accept inputs from encoders (that determine conveyor speed)and photo cells or limit switches (that determine part position). This informationis used to determine at what speed the multi-axis machine must run totrack the part and when the multi-axis motion program is to be executed. Thepurpose of this complex tracking and motion system is to provide gun dwelltime and powder pattern direction.

Robots

Most robots provide six axes of gun motion by adding wrist movement. Roboticmachines can be electrically or hydraulically driven. Because of their cost andcomplexity, these units are rarely used in powder coating systems. Anotherdetriment to these units is that hydraulic fluid is not something you want tohave around powder. Also, powder coating material is very abrasive and can playhavoc with hydraulic seals and pistons.

POWDER RECOVERY

A powder booth/recovery system must accomplish two specific goals: containthe powder overspray within the booth and remove the powder from this containmentair so that it can be reused or disposed of properly. Powder booths aredesigned using several filtration techniques to separate the overspray powderfrom this containment air stream depending upon if the system will reclaim thispowder or employ a spray-to-waste strategy, the number of reclaimed powders,and the time available to perform the color change.

Cyclone Booth System

A cyclone powder booth system, as pictured in Fig. 8, is made up of a spraybooth, cyclone(s), a cartridge collector, and possibly ductwork.The spray booth can be made of metal, plastic, or composite sandwichdesigns. Metal booths provides strength and durability but attract more powderthat will prolong color change time. Plastic will allow more light into the boothand will attract less powder, reducing color change time. Composite sandwichdesigns offer strength and attract the least power, significantly improving colorchange time. All powder booths should provide a smooth interior to facilitateeasy and thorough cleaning.Ductwork connection(s) can be at one of several locations. The preferredmethod is to locate the ductwork connection in the base of the booth as thisprovides a down-draft air flow inside the booth helping to keep it clean.The booth may have devices, such as baffles, to help control air flow withinthe booth, touch-up openings to provide access for manual spraying, and gunslots to provide access for automatic equipment.The cyclone is designed to separate most of the powder from the airflowbefore entering the filtration section. This has several benefits. First, air enteringthe filter is “precleaned,” which will lower the loading on the filter media. Thistranslates to longer filter life. Second, the powder collected in the cyclone canbe easily recycled. Since the cyclone is a cleanable device, color change is attainablewithout additional equipment. Multiple cyclones are used when air flowis so high that one cyclone isn’t practical for a given plant ceiling height. Twincyclones are used in parallel before the filtration section. Cyclone efficiency canvary by manufacturer and design with some systems delivering in excess of 90%of the powder into the reclaim device.The filtration section used with a cyclone booth is a cartridge collector, givenits name for the cartridges used to separate powder from the air flow. Thesepaper cartridges are cleaned with a “back pulse” of compressed air to shockthe powder from the cartridge surface. The cartridges will separate most of thepowder out of the air flow from the booth (up to 99% efficiency). These are notcleanable devices for color change. The blower fan that produces the air flow inthe booth typically is located on the clean air side of the filtration device. Finalfilters are used after the fan to remove powder particles, down to 0.3 micron insize, before the air is returned to the work environment.All of these devices—booth, cyclone, collector, fans, and absolute filters—canbe connected by ductwork. The velocity of air within this ductwork usually isabove 4,000 fpm and the ductwork is designed to promote laminar flow toassure “self-cleaning” during operation.Some powder booth manufacturers have taken the approach of reducingthe ductwork in this type of booth. This design has numerous smaller cyclonesattached directly to the powder booth wall. The booth airflow enters the cyclonesdirectly and without ductwork. These cyclones are much smaller than those usedin standard cyclone booths, allowing for simpler cleanup. The blower, filter pack,and final filters are downstream from, and attached to, thecyclones, allowingthe air to be returned directly to the plant.

Cartridge Booth System

The cartridge booth system (see Fig. 9) answers the same technical needs thatall powder recovery systems must address: safe containment and separation ofpowder coating overspray. In a cartridge booth system, this is accomplishedby filtration of powder from the containment air using a cartridge collectorattached to the booth. There are no external filtration devices (or ductwork toconnect them) with this system.The cartridge collector is usually located in the wall of the booth (side draft)or in the base of the booth (down draft). The powder-laden air flow entersthe collector. The air passes through the cartridge filter and the powder isdeposited on the filter surface. Periodically, cartridges are back-pulsed withcompressed air to shock the powder from their surface and deposit it in thecollector base. Powder in the base is pumped to a reclaim stand for reuse orto a container for disposal.The cartridge filter pack can be removed from the blower pack for colorchange. A separate cartridge pack is required for each recoverable color.Cartridges are made of a paper filter media. The blower pack houses the blowerfan and filter assembly. The blower is on the clean-air side of the cartridges. Airfrom this powder booth system is returned to the plant.The booth may have touch-up openings and/or gun slots depending uponthe application for which it is used. The booth is typically of metalconstruction,though some manufacturers prefer plastic. This type of powder boothsystem is known for its compactness. Safety is another important benefit tothis design. Since there are no “enclosed” devices the need for explosion ventingis eliminated.

cleaning, pretreatment & surface preparation

BUFFING WHEELS AND EQUIPMENT

BY DAVID J. SAX

STAN SAX CORP., DETROIT; WWW.STANSAXCORP.COM

Three elements to a successful buffing operation are the buff wheel, the buffingcompound, and the buffing machine. It is necessary to understand all of these elementsand how they interact to achieve desired quality, productivity, cleanability,corrosion resistance, reject elimination, and overall cost-effectiveness.

WHAT IS BUFFING?

Buffing is a mechanical technique used to bring a workpiece to final finish. Italso can be used to prepare the surface of a machined, extruded, or die-cast partfor plating, painting, or other surface treatment. The objective is to generate asmooth surface, free of lines and other surface defects.Buffing is not a process for removing a lot of metal. Deep lines and othermore severe surface defects should be removed before buffing by polishing witha polishing wheel or abrasive belt.Buffing usually involves one, two, or three steps: cut buffing, intermediatecut, and color buffing. These operations normally are performed by what isreferred to as either “area” buffing or “mush” buffing.

Cut Buffing

A harder buff wheel and, generally, a more abrasive buffing compound, are usedto start the buffing process. In cut buffing, the buff wheel and workpiece areusually rotated in opposite directions to remove polishing lines, forming marks,scratches, and other flaws.

Color Buffing

When a mirror finish is specified, a color buff step may be required. Colorbuffing may be performed with a softer buff wheel and less aggressive abrasivecompounds. In color buffing, the buff wheel and workpiece are usually rotatedin the same direction. This enhances the cut buff surface and brings out themaximum luster of the product.

Area Buffing

For localized finishing, narrow buffing wheels, positioned tangentially to theworkpiece, are used. This is often is referred to as “area buffing.”

Mush Buffing

To finish larger parts or parts having several surface elevations, mush buffingmay be used. This involves the use of one or more wide buff wheels. In mushbuffing, a part is rotated or cammed through the buffing wheel. This techniqueis also used to finish multiple products simultaneously.

BUFFING COMPOUNDS

Buffing compounds are the abrasive agents that remove minor surface defectsduring the buffing phase of the finishing cycle. Buffing compounds are availablein paste or solid form. There are thousands of products from which to choose.The prime consideration in selecting a buffing compound is the substrate beingbuffed and the surface to be provided.Nonferrous products made of copper, nickel, chromium, zinc, brass, aluminum,etc., frequently are buffed with compounds containing silica (generallyamorphous, often “tripoli”). “Tripoli” is found in a small area of Oklahoma andis shipped all over the world. Steel products are normally buffed with compoundsof fused aluminum oxide, which is available in DCF collector fines and as gradedaluminum oxide in a range of grit designations.Special abrasives are available for other purposes. For example, chromium oxideis widely used to give stainless steel, chromium- and nickel-plated products highreflectivity. Iron oxides are used to color buff gold, silver, copper, and brass. Limebasedbuffing compounds are used to generate mirror finishes on nickel products.Skilled buffing engineers can help manufacturers select the optimum equipment,buffing compounds, wheels, and buffing techniques. Cleaners and cleaningprocesses must be matched to the soil to be removed.

BUFFING WHEELS

Fabrics used in buffing are designated by thread count and fabric weight. Countis measured by threads per inch; weight by the number of linear yards per poundof 40-inch-wide fabric. Heavier materials have fewer yards per pound. Lowerthread count and lighter weight materials are used for softer metals, plastics,and final luster. More closely woven, heavier, and stiffer materials are used onharder metals for greater cut and surface defect removal. Stiffness is a result ofheavier weight, higher thread count fabrics, more material, specialized treatments,

sewing, and overall buff design.Buff wheel construction determines the action of the buff by making itharder or softer, usually by varying convolutions of the face of the wheel. Thisinfluences aggressiveness. Part configuration dictates buff design, construction,thread count, etc.

Conventional buffs employ a circular disk of cloth cut from sheeting andsewn into a number of plies. For example, some materials require from 18 to 20plies to make a -in.-thick section. Multiple sections are assembled on a spindleto build the required face width. The density of these types of buffs is alsocontrolled by spacers that separate the plies of fabric or adjacent faces fromone another.

Industry standards for the inside diameter of airway-type buff wheels are3, 5, 7, and 9 in. As a rule, productivity and buff wheel life increase as outsidediameter increases and thread count and material content increases. Largerbuffs and higher shaft rotation speeds also increase productivity and buff life.The choice of buff center size depends on how far the buff material can beworn before the surface speed reduces to a point of inefficiency, or flexibilitydeclines to a point where contours cannot be followed. Airway buff flexibilitydecreases with use as wear progresses closer to the steel center. Most airway buffsare designed with as much material at the inside diameter as the outside diameter.

Flanges

Buffing wheels require flanges for safe operation. Flanges must be sized for thespecific inside diameter of each buffing wheel. It is important for all buffs that theflange be designed with sufficient strength to withstand the tremendous forcesand pressures exerted in buffing. If buffs are not well designed and fabricated,centrifugal forces at higher speeds and the shock from operations can cause failureof clinching teeth, breakage of rings, and breakdown of buff sections. MUSLIN BUFFSThe most commonly used fabrics for buffs are cotton muslins. As previouslynoted, fabrics are designated by thread count (e.g., 60/60, 80/80, 86/80). Thesedesignations refer to the threads per inch in the warp and fill, respectively. Fabricweights typically run from 2.5 to 3.5 yd/lb. (Table I).

OTHER BUFF MATERIALS

Flannels

Domet flannel (with nap on both sides) and Canton flannel (nap on one sideand twill on the other side) in various weights are used where other fabrics fail toproduce a high enough luster. Coloring of jewelry products is a typical applicationfor such buff materials.

SisalSisal is a natural hemp fiber used for fast-cut buffing of steel and stainless steel. Itis a coarse fiber twisted into strand groups and frequently woven into a fabric. Ithas a much lower thread count than cotton muslin, sometimes five by seven perinch, and offers the advantages of greater surface defect removal. Combination

sisal/cloth buffs are effective designs (Fig. 1). The sisal plies frequently are clothcovered to omit the tendency of the sisal to cut the cotton threads of adjacent clothplies. Alternating cloth and sisal improves compound retention, reduces unravelling,and moderates cut. Kraft paper alternated with sisal also has applications.

Other Natural Materials

Occasionally, other materials are used to form buffs. For example, woven woolbuffs are used on plastics, soft metals, and sterling silver. Sheepskin buffs areused to avoid surface drag or smear when buffing metals that contain lead.Russet (bark-tanned) sheepskin is used for cut. White alum (alum-tanned)sheepskin is used for color buffing.

Pieced Buffs

Pieced buffs are less expensive because they are made of lower-cost materials.The buffs are made of colored segments, unbleached segments and occasionallybleached material.

Combination Buffs

Often different materials are combined, especially sisal with cloth, and occasionallypaper as well as cloths of different specifications.

Synthetic Fibers

Unwoven nylon and other synthetics fibers, because of their water resistance, may be used wet or dry or with wax or grease lubricants. Buffs made of syntheticsare usually operated at slow speeds, typically 2,500 sfpm, to prevent meltingand streaking surfaces.

BUFF TREATMENTS

Treatments may be applied to fabrics (mill treatment) or to the buff after assembly(dip treatment). Buff fabrics are frequently hardened and stiffened to promotefaster cutting, softened for additional flexibility to conform to contours,strengthened for longer buff life, or lubricated to prevent burning. Buff fabricsmay also be treated to provide improved adhesion of buffing compound, toabrade for heavier cut, or to flameproof and make fire resistant. Treatmentsmust be applied evenly and uniformly to avoid creating hard spots that causeuneven buffing. The treatment must not deteriorate with buff age. Unsuccessfultreatments weaken the cloth and decrease buff life.

CONVENTIONAL, FULL-DISK BUFF DESIGNS

Unsewn Buffs

Conventional, full-disk buffs are made with die-cut cloth disks. Unsewn, conven-tional full-disk buffs may be used forluster (Fig. 2). Loose disks are turnedto allow the threads of the material tolie in different directions. This resultsin more even wear, avoiding a squareshape after being put into use. Onedisadvantage of this conventionaldesign is that the fabric can fray orravel. When held against a wheel rake,a cloud of threads may fly off. Thisshortens buff life, increases compoundconsumption, and adverselyaffects finish. Also available are solidbias sisal buffs, with every other layerbeing cloth, and rebuilt buffs madefrom reclaimed material.

CONVENTIONAL SEWN BUFFS

Conventional, full-disk buffs for heavier buffing (cut) are sewn in various ways(Fig. 3). Closer sewing is specified for cutting harder metals and for removingdeep imperfections.Concentric sewing causes a buff section to become harder as it wears closerto the sewing and softer after wear causes the sewing to break through. Spiralsewing results in more uniform density. Square sewing produces pockets thathelp the buff wheel to retain more buffing compound. Radial sewing, sometimescalled sunray sewing, and radial arc sewing provide other variations. Tangent,parallel, ripple, zigzag, cantilever, and petal sewing are used for similar reasons.Special sewing, other than spiral, which is done on automatic machines, involves

Folded or Pleated Buffs

Folded buffs consist of circles of cloth folded twice to form a quarter circle,resulting in a “regular-pocket” buff (18 ply), or, for more cut, three times, toform eighths of a circle to constitute a denser “superpocket” (34 ply). The segmentsare laid down to form a circle, with eachsegment overlapping the previoussegment. They are sewn around the arbor hole and partway to the periphery.The folds form pockets that hold compound and flex sufficiently for contourfollowingcapacity. Folded buffs share three design deficiencies: lack of centerventilation, a tendency to fray, and waste of material in the unused center.

Pleated Buff

Airway buff cloth may be accordion pleated to present more angles of materialto the surface of the product to be finished. Pleating results in more cloth anglesto reduce streaking and improve coloring characteristics. Better cutting is alsoachieved in some applications.

Packed Buffs

Buffs may be packed with spacers consisting of cloth or paper inserted betweenthe larger diameter plies. The same spacer principle is used between buff sections.Both measures result in a softer wheel face. The packed buff constructionis effective in contour buffing applications.A version of the packed buff, for threaded, tapered spindles (2-12-in. diameter),is used in the jewelry industry. The center is hardened, usually with shellac.The sides of the buff may be reinforced by leather disks.

Pieced Buffs

Pieced buffs may be used in place of sewn full-disk buffs. They are made fromremnants of cloth left over in the manufacture of other textile products. Suchbuffs require one of the types of sewing used for full disks in order to staytogether in use. The chief virtue of pieced buffs is their higher value owing tothe lower cost of materials. They usually are sold by the pound (see Table II).

BIAS-TYPE BUFF WHEELS

Bias buffs are more frequently used than conventional forms. They combineflexibility and cutting power. Bias buffs are cool running and resist burning.They are naturally ventilated. Side openings in flanges, center plates, and tabs,resulting in spacing between sections, enhance their cool-running characteristics.By using material cut on the bias, the threads form an “X” at the peripheryof the buff. Threads are held at a 45oangle by cross-threads. This minimizesfraying and raveling (Fig. 4).Strips of bias-cut fabric are sewn into continuous rolls. After the rolls arecut to proper length, they are wrapped around a hub or core. They are thenpulled to the desired inside diameter within the channel, usually by means ofsteel blades in an “Iris” machine. Straight-wound material wrapped aroundan oversized wheel results in a convoluted or “puckered” face; thus, the term“puckered” buff.The “puckered” face design of bias buffs tends to break up lines left in thesurface of a product from previous operations. Increasing the size of the drumsvaries the amount of pucker in the face. The bias buff can be adapted to various

contoured parts and degrees of cutting and coloring. An advantage of the “Iris”-made buff is the elimination of material beyond the inside diameter to the arborhole. Thus, more of the cloth is available for use. VENTILATED BIAS BUFFSAlthough the puckered characteristic of bias buffs results in cooler running,some operating conditions require additional cooling. Steel centers with holesand ridges are designed to collect and divert more air. The air cools the buffand the workpiece surface. Clinch rings permit use of reusable metal inserts for

substantial savings (Fig. 5).

PUCKERED BUFFS

Puckered buffs are rated by numbers. Higher numbers indicate greater clothcontent, buff density, and face convolutions (Fig. 6). Higher densities and closerconvolutions increase cutting and reduce streaking.

Open-Face Cloth Buffs

The open-face buff prevents loading, packing, clogging, and ridging duringfinishing operations. The plies are configured differently from the closedfacedesign. Buff material is wound singly or in groups of two, three, four, ormore plies. Open-face buffs may be “straight wound” or “spiral wound” for acorkscrew or cross-cutting action that further minimizes streaking. Buff densityvaries with the number of plies, the amount of cloth, thread count, fabricweight, and treatment of the cloth. Buff pressure, speed, angle to the part, clothstrength, compound absorption ability, ventilation, and cloth flexibility arevaried with buff design.Table II. Approximate Weight Table for Spiral Sewed Pieced Buffs

BIAS SISAL BUFFS

“Iris” equipment used to gather cloth buffs is adapted to sisal and other materials(Figs. 7-10). Some bias sisal buffs are tapered (wider at the outside thanthe inside diameter). This reduces gaps between hard sections that could causestreaking. The tapered bias sisal buff is a long-life, cool-running buff for steeland stainless steel. Hard bias sisal buffs also are used in place of some beltingoperations, as well as in deburring and brushing.

Open-Cloth Bias Sisal Buff

The open cloth bias sisal (OCBS) buff is used on contoured steel and stainlesssteel parts (Fig. 9). It consists of woven sisal and cloth, four plies of each(eight plies total), bound together by concentric sewing before Iris gathering.The buff is manufactured in endless strips, cut to length, rolled aroundsplit drums, and gathered into clinchrings by the “Iris” machine. A variationof the open-cloth bias sisal buff is theopen double-cloth bias sisal (ODCBS)buff. This design consists of two layersof cloth sewn together with one layer ofsisal to make a 12-ply buff of eight pliesof cloth and four plies of sisal.

Spoke Unit, or Finger Buff

Spoke unit or finger-type buffs combinegreat cutting power with the capacityto flex and accommodate contours andallow better workpiece coverage with

Fig. 4. Bias buff (left) versus conventional buff (right). Thread configurations of bias buffs alternate

warp and filler threads. Biasing provides design efficiency by exposing all thread ends to the surface

being buffed, reducing fraying of the fabric.

Fig. 5. Steel clinch ring (left) and steel clinch ring buff

with open center (right). Buffs that are constructed

by the clinch ring or “Iris” machine method have

superior ventilation and cloth biasing, and optimal

material utilization.

fewer buffing heads. Spokeunit or finger-type buffs are made from materialsthat include soft cloth, stiff cloth, sisal,and coated abrasives. The material ismanufactured into units, or fingers,sewn into endless belts, cut to length,wrapped around split drums, and gathered

by an “Iris” machine into steelteeth. The spoke unit or finger sisalbuff is usually made with woven sisalinterlaced with 86/80 cloth. Acid or

rope sisal is sometimes used. The clothmay be mill or dip treated (Fig. 10).The spoke or unit bias buff runs

cooler than standard bias buffs andhas a knee-action flexibility that givessuperior contour-following ability. The width and number of the individual unitsis varied within limits. The range of buff density, or hardness, is varied by choiceof materials, treatments, (buff center size) plies, and type of radial stitching. Somecomplex products are best finished with this type of buff.

FLAP BUFFS

The flap buff (Fig. 11) utilizes separate flap units placed at right angles to thedirection of rotation of the wheel. Each flap supports the other to produce asmooth running wheel. Flap wheels were originally designed for bumper polishingand buffing operations. Flaps are made of coated abrasives, sisal, cloth andcombinations thereof.

POLISHING WHEELS

Polishing wheels are usually made of conventional cloth buff sections glued orcemented together. Canvas disks are cemented to the sides to protect the sewing.Glue or cement is applied to the face. Faces are struck with a pipe at anglesand cross-angles to form a uniform crisscross of cracks on the polishing surfaceand provide sufficient resiliency to allow the wheel to make better contact witha workpiece.Buff sections used to make polishing wheels are generally spiral sewn andmade of various types of cloth, sisal, canvas, or sheepskin. Solid, one-piece woolfelt, and bull neck and walrus hide are occasionally used.Conventional straight buff sections that are glued together may cause streakingduring polishing. An alternative involves inserting pie-shaped segments or

other spacers between the buff sections to result in a “nonridge” polishing wheelthat eliminates streaking. Various abrasive and adhesive combinations are usedto grind, polish, and satin finish. These include liquid, graded aluminum oxideabrasives, greaseless compounds and burring bar compositions.

BUFFING EQUIPMENT

Significant improvements have been made in buff wheels and buffing compoundsto provide consistent and predictable performance. This has helpedmanufacturers of automated buffing machines to develop automated equipmentfor low- as well as high-volume requirements and to minimize labor andoverhead in the finishing operation.

Fig. 6. Cloth bias buffs in order of increased

density from closed face (left to right: 0, 2, 4, 6)

to open face (far right) design.

MACHINE DESIGN

Mechanical buffing systems have a motor-driven shaft to which the buff wheelis applied. In addition, most machines will have a positioning mechanism, afinishing lathe, and workpiece-specific fixtures.

POSITIONING MECHANISM

Automated buffing machines orient parts against the media by mechanicalmethods to duplicate or replace human motions. They rotate, oscillate, tilt, andindex the wheel and/or the workpiece.

Fig. 7. Conventional sisal buff. Fig. 8. Bias sisal buff.

Fig. 9. Open cloth sisal buff. Fig. 10. Spoke unit or finger sisal buff.

Finishing LatheThe finishing lathe is a device located inrelation to the positioning mechanism.It allows a buff wheel to contact one ofmore surfaces of the workpiece at predeterminedlocations.

Fixturing

The workpiece fixture or tooling is used toposition a part during the buffing cycle.Buffing machines can incorporate singleor multiple fixtures. Fixtures can also bedesigned to automatically reorient a workpieceduring the buffing cycle. Buffingfixtures are unique to each part being processed,although some may be adapted to anassortment of similarly shaped parts. Thedesign of fixtures is extremely important.

Unless a part can be fixtured properly at areasonable cost, the economical utilizationof finishing equipment cannot be justified.

TYPES OF BUFFING MACHINES

Buffing machines fall within three broadcategories: manual, semiautomatic, andfully automated.

Manual Machines

Manual buffing machines are used in low-volume applications and applicationsinvolving the buffing of extremely complex workpieces. Manual machines, whenused in conjunction with the proper buff wheel and buffing compound, can bemanipulated.

Semiautomatic Machines

Semiautomatic buffing machines are used in lower volume applications where asingle finishing operation is performed on a variety of parts. Initial investmentand fixturing and operating costs are low.Semiautomatic finishing machines can be used with a single- or double-endlathe. One operator can be employed to load, unload, and operate equipment.Semiautomatic machines hold the workpiece and present it to the buff wheel. Atimed cycle controls dwell and retraction. Only one fixture is required for eachmachine for each type of part finished. Because the machine supports the part,operator fatigue is minimized. Various types of rotation also can be performed,depending on the type of semiautomatic machine selected.Production of semiautomatic buffing machines depends on part configurationand the degree of finishingrequired. By using a double-end jack with two semiautomatics,an operator can load one machine while the other is finishing a part.This can double production without increasing labor costs.

Fully Automatic Machines

Fully automatic machines are used in high-volume applications and where multiplesurfaces of a workpiece must be finished. The two most common types ofautomatic buffing machines are rotary automatic and straight-line machines.

Rotary Automatic Machines

Rotary machines have round tables with finishing heads located around theperiphery of the table. This type of machine is typically used to finish simple,round parts requiring high production. The number of finishing heads andproduction determine the size of the rotary.The table of the rotary machine can move continuously or index to start, stop,dwell, and then start again, with the length of the dwell controlled by a timer.The configuration and area of the product to be finished determine which isbest. Production is higher on a continuous rotary machine because the tabledoes not stop rotating. On an indexing rotary machine, because of the stop,dwell, and start cycle, production is lower. Parts that have surfaces that are difficultto reach and require more dwell time in certain areas may be finished on anindexing rotary machine to obtain the dwell time necessary. On each table thereare rotating spindles on which the parts are fixtured for the finishing sequence.Rotary tables may have a greater number of fixtures than indexing tables, sincethe production and simple configuration make it more appropriate to be runon a continuous machine due to the ease of reaching all surfaces.

Straight Line Machines

There are various types of straight-line automatic finishing machines. Normally,linear workpieces are finished on straight-line machines. Straight-line machinesalso can be used to finish round parts if extremely high production is required.There is less limitation on workpiece size as with rotary equipment.With straight-line automatic machines, finishing heads can be placed on bothsides of the machine. In addition, various heads can be incorporated into thesystem for buffing and polishing. With rotary equipment, the outside peripheryof a rotary table is used.Various types of straight line machines include:Horizontal return straight lineNarrow universal straight lineOver and under universal straight lineReciprocating straight lineOpen-center universalThe size or length of these straight-line machines can be designed and built

to accommodate the desired end result; floor space is the only major limitation.Each machine normally requires only one operator for load/unload. All operationsof these machines are controlled from a push-button panel located nearthe operator for starting, stopping, and controlling various functions.

COMPUTER NUMERICAL CONTROL BUFFING MACHINES

Buffing machine manufacturers can build equipment offering the same levelsof control and flexibility available from computer numerical control (CNC)metal-cutting machines. Separate CNC workcells can be designed to combinebuffing with deburring operations within a given and limited series of processsteps. It also is possible to integrate a complete sequence of manufacturingoperations through a universal, plant-wide parts handling system to combinefabricating, machining, deburring, polishing, buffing, painting, plating, andpackaging. Such systems have a significant impact on material handling costs,daily in-process inventory levels, direct labor costs, plant floor spacerequirements,safety, and overall productivity.CNC buffing systems offer a number of significant advantages. Equipmentis programmed on the shop floor for reduced setup time. Buffing cycles can bereprogrammed to accommodate changing production requirements. Productiondata are automatically collected to support statistical process control requirements.Most important, quality is improved because part-to-part tolerances areconsistent and repeatable.

WORKPIECE HANDLING

Significant advancements have been made in materials handling technologyas it relates to buffing. A broad range of application-specific options is offered.These include pick-and-place workpiece load/unload systems, “blue steel” rollerconveyor systems, lift-and-carry and shuttle-type in-line part transfer systems,trunnion-type transfer tables, power-and-free conveyor systems, robotic worktables,and automated guided vehicles for transferring parts between machines.

SUPPORTING TECHNOLOGY

Buffing systems are increasingly becoming turnkey, integrated installations. Inaddition to the basic machine, equipment builders can offer a variety of supportingsystems to ensure increased performance and improved quality.Electronic options, beyond programmable controllers and computer numericalcontrol systems, include the use of load torque controls, sensors, proximityswitches, encoders, digital read-out devices, laser gauging, and LED programmablecounters. Other supporting systems include quick-change and modularwheel assemblies, automatic tool compensation, automatic buffing compoundapplication systems, dust collection systems, and automatic workpiece shuttleand load/unload systems.

SUMMARYEffective buffing is accomplished through the proper selection of buffing compound,the buff wheel, and the buffing machine. In most instances, it is recommendedthat prototype or test parts be processed under production conditions to establish process parameters and prove production rates and quality.

finishing equipment & plant engineering

CONSIDERATIONS IN THE FINISHING

EQUIPMENT SELECTION PROCESS

CJI PROCESS SYSTEMS, SANTA FE SPRINGS, CALIF.

When budgeting for new finishing equipment or upgrading an existing line,

it is important to note that each requirement is unique and must be carefullyconsidered before estimating a price. Otherwise, when the real purchase ordermaterializes for the quoted system, all of the pre-engineering data must be available,as well as current costs, in order to build a particular line. This article willdescribe several key considerations in the selection process of a custom manualor automated plating, anodizing, or chemical process system.Beyond the obvious—selecting floor coating, secondary containment trays, orberming, power, air, and exhaust requirements—the equipment selection processmight proceed as follows:

• The equipment estimator must first collect all the data.

• Then, a determination of how many parts are to be finished peryear, month, week, day, must be broken down into hours per day,in order to size the process line.

• Pretreatment requirements, such as burnishing, tumbling, deburring,buffing, polishing, or degreasing, and selection of any specializedequipment, must be considered.

• Selection of the process, which will depend on whether the partsneed to be barreled or racked, is yet another factor.

• Determine a plating or anodizing process cycle for the particularbase material, as well as the configuration of the parts.

• Determine if the plating thickness requires electroplating,immersion, or autocatalytic (electroless) processing or Type I, II, or IIIanodizing, etc.

• Carefully calculate the surface area of a single part to determinehow many parts may be loaded per barrel, rack, or fixture.

• If the parts are to be barrel plated, then determine if the parts willnest, or stick together; and, if so, what type of barrels will be used.

• If the parts are to be racked, then each part needs to have a specialrack or fixture designed to accommodate that special part. If morethan one rack per flight bar is required, determine just howmany racks per load will achieve the best results.

• Masking considerations: Many parts will require masking withspecial tapes or waxes, as well as holes plugged with custom plugs.

• Reels of connector parts might require selective plating only insome areas, especially where precious metals are plated.Customized selective strip plating lines will be required for eachspecial application.

Once the production quantities are determined, then the plating facility mustbe sized accordingly. The plating tanks must be laid out, and the footprint of alllines and systems measured, with optional floor coating, double containmentof the tanks, with catwalk and grating provided. If a manual line is sufficientfor the desired production volume, with one or more operators, then it mustbe determined if anoverhead hoist will be needed—and if so, will it be a manualchain hoist, powered trolley with push button, or joy stick variable-speed motorized hoist.

???

Automatic solar panel plating line.

(All images courtesy of CJI Process Systems)

Phosphate line.

If an automatic hoist line is needed,then you’ll need to determineprecisely how many hoists will berequired. Depending on the configurationof the line, there might beparallel lines, side by side, with load,unload at the same end, or load onone end, unload on the other end,and with either wet or dry shuttletransporting the barrels or racksfrom one side of the line to the other,or a U-shaped return line, and dryer.The PC software must be programmablein order to allow controlof all the process parameters, suchas solution operating temperatures;low-level shut off, alarms, auto-fillof tanks; variable or constant currentand voltage requirement of therectifiers; cathodic or anodic; automaticramp up of voltage for anodizing;historical process data recordedfor future records; hoist location,position, and speeds; pumps andfiltration operation; air blower pressure;and amp min/hr. Other parametersto consider are chemical dosing,and if any brightener feeders orchemical feeders are supplied withmetering pumps, etc.In order to design the plating line(s) correctly, key items must consideredfor every single tank in the line. The designer must go through each station ortank, one at a time, to decide which controls or accessories need to be installedon each tank. A manual line would need the same items as an automated line,except the automated line would have either single or multiple programmablehoists, which might be either a monorail type, sidearm, semi-bridge, bridge, or a“rail rider.” The hoist positioning might be laser-controlled encoder or manual,with random loading scheduling—or it could be time-way based. The line mightbe totally enclosed because of either clean room or other environmental circumstances,with the operator working inside the enclosure.All of the tanks must be sized to accommodate the barrels, or racks, with sufficientclearance for the heaters, sensors, coils, pumps, filters, spargers, level controls, anode baskets, etc. The tank materialmust be chemically compatible—withthe decision to either line the tank,or offer it without linings or innercoatings—for each solution, as wellas each individual component. Eachtank must be outfitted with a varietyof components, based on just whatthe tank is supposed to accomplish.The soak cleaner would needeither electric heaters or heatingcoils, temperature controllers, sensors,hi/lo level sensors, individualsolenoids for city water or deionizedwater feed, agitation sparger(with agitation either provided bylow-pressure, oil-free filtered air),or eductor/pump agitation. Othernecessities: oil skimmer, oil coalescer,pump and filter, and low-levelshut off of the heater.The rinse tanks might requireauto-fill city or deionized water solenoids,air sparger manifolds, drainvalves, overflow weirs, conductivitycontrollers, and possibly pump andfilter, depending on particulate drug into them. Electro-cleaner tanks wouldalso need a rectifier, anode/cathode bars, pump and filter, oil skimmer, heateror steam coil, solenoids for city and deionized water feed, etc.The process tanks would require similar components as the electro-cleaner, withan addition of rectifiers and other items, depending on the process. The rectifiersmight be chosen to accommodate a variety of controls, such as constant currentand/or constant voltage (pulsed, periodic reversed, or reverse pulsed; air, water, orconvection cooled), and might include analog or digital amp/volt meters mountedremotely. The designer must decide just what type of heaters, agitation, cooling,filtration, circulation, rectification, and materials of construction, as well as whatneeds to be exhausted and which tanks need exhaust plenums. CFM requirementsalso need to be calculated for the entire line in order to size the air scrubber.If the plating tank happens to be an electroless nickel process, then the decision

must be made as to how to heat the tank. For example, would it be morepractical to use heaters, steam, or hot water coils? Or does it make more sense to make the tank a double-boiler tank heated with coils in the lining of the tank?

???

Rear view of large plating line.

Automatic electroless nickel plating line.

CONSIDERATIONS WHEN DESIGNING A TANK

There are many considerations when building the tanks, including size, quantity,and spacing of the girths around each tanks, as well as factoring in the weightcapacity of each solution. All of this depends on specific gravity, operating temperature,and geographical location. On the West Coast, for example, you mightrequire seismic calculations on the larger tanks.The plating lines might be either individual tanks sitting on a frame or mod- ules. Either way, the lines should be plumbed with valves, solenoids, city anddeionized water feeds, with separate drains to cyanide, acid/alkaline, and chromelines to the wastewater treatment system.Note: every plating facility will needsome type of treatment system, unless it’s all hauled away and treated off site.The plating line should offer single-point connections after arriving for hook upof the utilities, air, water, or steam, and electricity. Most plating lines are wired“three-phase” wherever possible for energy efficiency savings.Some plating lines are required to provide VFC (variable frequency controls)that vary the speed of the electric motors on the pumps, etc., depending on loadrequirements.The wastewater treatment system must have many components to accommodatethe plating line, and the plating line designer is usually asked to also quotethe wastewater system supporting the plating or anodizing line. Aside fromconsiderations regarding the wastewater treatment methodology of each platingline, the designer must determine just which type of system will be the mostefficient system for that particular line while satisfying the local permitting laws.

CONCLUSIONS

The aforementioned factors should offer readers just a few examples of themagnitude of calculations, researching, sizing, etc., that might be required whenestimating a new system. If the process line is designed properly to begin with, then the chemistry will have a much better opportunity of being successful.

شرکت جلاپردازان طراح و سازنده خطوط آبکاری

 این شرکت بسته به نیاز شما خطوط آبکاری و پوشش را طراحی کرده و مطابق با توافق با مشتری تولید میکند از جمله این خطوط

خطوط آبکاری فسفاته کاری و سیاه کاری

خطوط آبکاری آندایز معمولی و آندایز سخت hard anodiz

خطوط آبکاری گالوانیزه یا آبکاری روی و آلیاژ های آن

خطوط  آبکاری نیکل کرم

خطوط آبکاری مس 

خطوط آبکاری کرم سخت hard chorom

خطوط آبکاری گردون و ثابت برای فرایند های مختلف

خطوط پوشش های خاص مهندسی

چند نمونه ساخته شده:

تجهیزات اتوماتیک پوشش

خشک کن سانتریفیوژی

دستگاه چیلر مناسب برای خطوط پوشش آندایز معمولی و آندایز سخت

  دستگاه اسکرابر مناسب برای  تصفیه هوای خروجی از سیستم تهویه هوای کارگاه

 خط اتوماتیک پوشش کاری طراحی مطابق با نیاز های شما

نکات لازم در نصب خشک کن سانتر یفیوژی تولیدی شرکت جلاپردازان 

1. *درهنگام نصب از ضربه گیر لاستیکی استفاده شود.
2. *در صورتی که پس از روشن شدن دستگاه لرزش دارد باید جایگاه نصب و تراز بودن و هم ترازی سطوح ضربه گیر مورد بازبینی قرار گیرد.
3. *برق ورودی به دستگاه 3 فاز بوده و نصب آن به گونه ای باشد که به منظور کارایی بهتر و ایجاد جریان مناسب هوای گرم به صورت ساعت گرد چرخش نماید.

نکات ضروری در نگهداری دستگاه هنگام کار

1. *گریس کاری یاتاقان ها به صورت ماهانه انجام گردد.
2. *از پاشش محلول های متنوع و آب به قسمت الکتروموتور جلوگیری شود.
3. *هنگام روشن کردن خشک کن درب آن به طور کامل بسته شده باشد.
4. *از بازکردن درب هنگامی که هنوز خشک کن در حال چرخش است خودداری نمایید.
5. *هنگامی که درب خشک کن باز است از روشن کردن آن بپرهیزید.

چگونگی و نکات مهم در نصب خشک کن سانتریفیوژی

1-دو عدد تیرآهن (ناودانی 14)را به صورت افقی به فاصله پشت به پشت71 سانتی متر (فاصله دو سوراخ کفی خشک کن) در جای مناسب قرار دهید.
2- با استفاده از بتن دو تیر اهن را در محل مورد نظر محکم کنید( بتن ریزی به اندازه ای باشد که 2 تیرآهن به طور کامل در بتن قرار گرفته باشند).
3- چهار عدد پیچ 16 روی تیر اهن ها به فاصله سوراخ های کفی خشک کن روی تیر آهن ها جوش دهید.
4- برای هر پیچ از یک ضربه گیر لاستیکی مناسب استفاده کنید .
5- پس از قرار دادن ضربه گیر در پیچ ها ، خشک کن را در جای خود قرار داده و مهره های آن را محکم کنید.
6- دقت نمایید که صفحه کفی خشک کن پس از نصب کاملا به صورت افقی تراز باشد.

  برای اطلاعات بیشتر با شرکت جلاپردازان پرشیا تماس بگیرید

021.65734701-3

شرکت جلاپردازان طراح و وسازنده تجهیزات آبکاری

طراحی سازه های فلزی خطوط شامل شاسی خطوط آبکاری/ هند ریل واک وی ، گریتنیگ (تردد پرسنلی) در خطوط آبکاری

شماره های تماس جهت کسب اطلاعات بیشتر

021.65734701-3

سایر تجهیزات آبکاری

شرکت جلاپردازان تولید کننده تجهیزات آبکاری به سفارش مشتری میباشد 

جهت اطلاعات بیشتر با ما تماس بگیرید

021.65734701- 3 جلا پردازان پرشیا

سایر تجهیزات آبکاری

شرکت جلاپردازان تولید کننده تجهیزات آبکاری به سفارش مشتری میباشد 

[widgetkit id=17]

finishing equipment & plant engineering

ENERGY AND RESOURCE REDUCTION

FOR AUTOMATED FINISHING SYSTEMS

کاهش مصرف انرژی و منابع در تجهیزات اتوماتیک آبکار

Finishing equipment & plant engineering

ENERGY AND RESOURCE REDUCTION

FOR AUTOMATED FINISHING SYSTEMS

تهیه شده در واحد تحقیق جلاپردازان پرشیا

تیر 97

BY TIMOTHY J. KURCZ, DIRECTOR OF SALES, JESSUP ENGINEERING, INC.,

ROCHESTER HILLS, MICH.

OEM and independent job shops can benefit tremendously from investment innew automatic finishing equipment by operating faster, more efficient machinesthat deliver repeatable quality with reduced labor. Knowledgeable buyers increasinglydemand integrated computercontrols to manage water and chemistryreplenishment, rectifiers, ventilation and air makeup systems, and wastewatertreatment to reduce energy and resource consumption and associated ongoingcosts.Before management features can be designed, a new machine should be

carefully sized to meet current and future production requirements. The veryfoundation of energy management begins with proper sizing of the rack, barrel,or basket — collectively known as the work package. Total work package surfacearea is critical for rectifier sizing; chemistry and rinse water replenishment.For racks and baskets, the work package is defined as the width, height, lengthdirection of travel (DOT), and load weight, plus liquid if very large or cuppingparts are processed. Barrel capacity is defined as the width, diameter, and loadweight: A long-established rule of thumb suggests 33% fill for plating and 80%fill for coating (volumes) are typical for barrels.With the work package established, overall dimensions are used to determinetank size and hoist capacity. The objective is to limit tank surface area tothe greatest extent possible, thus reducing evaporative losses and floor spacerequired. Maximum load weight, combined with rack or barrel weight, dictateshoist capacity, including lift, transfer, and up-rotation motor sizes.One more step is needed before machine footprint can be established: It is critical to secure chemistry supplier input when developing a process sequence

????.

Figure 1. High-efficiency full machine enclosure. (Photo credit: Photography by Colleen Sadlik, CreationsMadeSimply.com.

They provide technical process details, including baths and temps, immersiontime, rectification, number of rinses, dry time, and water supply requirements.During the machine layout phase, it may be prudent to add space for additionalprocess tanks, rinses, or dryer cells to accommodate future expansion.Alternately, the work package might be expanded to enable increased futurecapacity should floor space limit DOT additions.Money is usually better spent increasing the work package of a single machine,compared with the cost and space required for a second future machine. Forthat reason, multiple processes should be considered at this time. Potentialmachine builders should willingly provide preliminary layouts, cycle analyses,and resource consumption estimates to assist decision making.Once agreement is reached between the plating shop, chemistry supplier,and machine builder, application of available resource reduction technologycan be applied. Implementation can make a significant difference in long-termprofitability. Concepts and features presented are easily implemented in newmachines (Figure 1), and can be retrofitted into existing automatic finishingsystems with careful engineering.

ENERGY & LABOR REDUCTION

Simple, rugged, reliable hardware and easy-to-use controls make best use ofresources when run round-the-clock. Individual rectification improves processefficiency and part quality when integrated with in-process weighing or otherworkload measurement systems. For shops running short schedules, end-of-shiftor weekend auto-shutdown enables energy reduction. Auto-start-up ensuresthat an automated finishing system is ready for operation without the need forset-up personnel.Recipe-driven individual cell rectification enables precise, repeatable platingthickness for every load regardless of part count for rack plating, or by weightfor barrel plating operations. This feature can calculate surface area on a discreetpart number basis. Operator-entered load data assures precise amp-square-foot(ASF) delivery for rack plating systems. Barrel weight is verified by load cells,assuring precise rectification settings.Hoist improvements reduce energy consumption and enable faster motions,reducing wear and improving operator safety for finishing systems. Highefficiency,VFD-controlled motor/drive combinations provide the smoothestpossible motion profiles and reduce electrical energy consumption. Corrosionproof

belt lifts reduce drag and dramatically extend maintenance intervals.Full-length, non-contact absolute linear encoders allow faster, smoother, moreprecise hoist positioning and virtually eliminate rack or barrel shake. Thesefeatures reduce energy consumption, downtime, and maintenance cost formachine operators.

WATER & CHEMISTRY REDUCTION

Given today’s pressure to conserve earthly resources, it’s prudent to make efficientuse of water and chemicals. Advances in fluid devices and managementcan dramatically reduce consumption of both. Naturally, computer controlsare at the core of production-based rinse water replenishment and chemistryaddition functions.Production-based, load-by-load rinse replenishment can optimize water

consumption on a recipe-driven basis. This feature enables experimentationwith minimum rinse water volume necessary to ensure quality processing.The ultimate goal is to reduce water usage, which also reduces wastewatertreatment volume and associated chemistry consumption. The result is lesswater purchased and treated because there is no rinse water flow between cycles.Similar to water replenishment techniques, recipe-driven chemistry additionreduces usage and improves bath quality by eliminating saw-toothfluctuationscommon with less frequent manual additions. This precision is available onlyby an integrated PC/HMI, needed to recognize and manage parts, select recipes,and adjust for rack or barrel fill variation. Advanced controls allow local and/or remote adjustment of replenishment at any time during machine operation.Generation of RO water costs floor space, energy, water, and money.

Discussion with your chemistry supplier (water analysis report in hand) willdetermine if RO water is recommended or needed for a plating or coatingprocess. Use may be recommended because of unsuitable local water quality, orrequired for a specific chemistry, regardless. Makeup, addition, and replenishmentfor evaporative losses can sometimes be accomplished with rinse waters,reducing the need for fresh water.Careful consideration should be given to plating and coating barrel design.Cylindrical plating and coating barrels offer a 17% increase in capacity comparedto hex style barrels. Further, more consistent anode-to-work relationshipimproves efficiency for plating systems. Part-specific tumbling rib and perforationconfiguration contributes to efficient rollover, quicker drainage, andreduced drag-out.Recipe-driven, up-barrel rotation drains directly to the process tank, a featureespecially important for parts known to cup solution. Up-barrel rotation should

be considered mandatory in today’s highly competitive finishing environment.

???

Figure 2. Enclosed ventilation system in action. (Photo credit: Photography by Colleen Sadlik, CreationsMadeSimply.com.

WASTEWATER TREATMENT

BASICS

Critical to resource reductionstrategy is a basic understandingof water consumption drivers.Water use begins with total purchasedand ends the total waterdischarged, a variable expensethat directly affects operating cost.Metrics are discussed in terms ofloads per hour, parts per hour, gallonsper hour, etc.Consumption is almost purelya function of surface area. A cruderule-of-thumb indicates approximately

one gallon of drag-out isgenerated for every 1,000 squarefeet of surface area processed,including work, rack, barrel, orbasket. The total will vary dependingon the shape, size, and orientationof parts in process. It is criticalto know the surface area andthe number of parts required perhour. Fortunately, most parts aredesigned in CAD, so area is easilyfound. With surface area known, solutiondrag-out and water consumptionis calculated and expressed ingallons per hour. Water treatmentexperts suggest every gallon of dragoutrequires approximately 600gallons of rinse water to maintainappropriate dilution levels. Totalannual water consumption canthen be calculated. Be aware rinsesmay require RO water, a processthat is approximately 75% efficient.The 25% loss should be added tototal water consumption calculations.Machines should be designedto reduce solution drag-outby any/every means possible.Opportunities include efficientrack, barrel, basket, or rotatingbasket design, long drain dwells,up-barrel rotation (Figure 2), largestpossible round or slotted barrelperforations, tipping, tilting, or verticallyoscillated racks (Figure 3), recirculatingspray clean and/or multiplecleaners, over tank top sprays,and engineered flow in rinse tanksall contribute to drag-out reduction(Figure 4). Clearly, machine designshould be a cooperative effort.

* It is important to notethat water treatment is anevolving science. Federal,state, and local environmentalregulations regarding wateruse and treatment — and the methods and cost of treatment anddisposal of spent process chemistry and/or sludge — are beyond thescope of this article and should be addressed with a competent watertreatment supplier.

VENTILATION & AIR MAKEUP MANAGEMENT

While the latest technical advancements are installed on new machines, oldersystems suffer due the perceived high cost of installation and associated downtime.As a result, air management too often remains a footnote in the energyreduction portfolio. It deserves closer review as improvements can be installedin phases to save finishers energy and cost.The least invasive improvement is to install VFD controls for the ventilationblower, which is slaved to tank temperatures. This offers the opportunity toslow ventilation output as tanks cool during overnight or weekend shutdowns,or may be shut down completely when temperatures fall to a predeterminedlevel. Further, should your finishingsystem reside within its own room ora defined air makeup zone, additionalsavings can be achieved if VFD controlsare added to throttle the makeupsystem, which is, in turn, slaved tothe ventilation system.More complicated to design andinstall, a full machine enclosure canoffer several benefits. They reducetotal volume of ventilation airrequired, and reduce or eliminate disruptiveexternal transient air flows,which can adversely affect push-pullventilation systems. Furthermore,operator safety is often improvedbecause the transparent ventilationbarrier is located between the catwalkand automation.

* It is important to note thatindustrial ventilation andscrubbing technology is anevolving science. Federal, state,and local regulations regardingemissions — and the methods andcost of air treatment — are beyond the scope of this article and shouldbe addressed with a competent ventilation system supplier

CONTROL, MONITORING, RECORDING, REPORTING

PC/HMI operation of finishing systems should be considered standard for allfinishing systems. Error-proof NADCAP & ISO processing is possible if themachine is equipped with appropriate sensor technology. Data such as tanktemperatures, immersion times, rectification, pH, conductivity, rotation/oscillationspeed and/or duration, chemistry additions, drain dwells, dryer temps,and water usage, are collected, stored, and exported to the customer databasefor analysis and report generation.From an operational standpoint, engineered process cycles offer the mostefficient production performance, though mixed processes and variable platetime cycles are available at the cost of some productivity. Most operators preferfixed production rates so load/unload operations and external logistics remainunaffected.Regardless of operational strategy, machine operation must be simple and intuitive.A user-friendly, multi-lingual, touch screen, human machine interface (HMI)is a necessity in today’s finishing environment. A PC with MS Windows-basedsoftware offers easy PLC interface and requires no special programming skill.Recipe upload is typically accomplished with bar code scanner technology.Most important: Individual rectifier, chemical, tank level, tank temperature, ventilation,and wastewater management functions can be easily managed througha security-coded interface. Additional features may include monitoring andcontrol of hoist equipment, process tanks, and accessory equipment.Performance monitoring may include shift reports for total time and numberof cycles run, tracking of automatic vs. manual operation, load/unload delays,

and fault data. To speed correction of unexpected stoppages, a well-designedcontrol system will provide automatic system diagnostics. Detailed screensshould annunciate and display fault location and actions needed to quicklyrestore production. Internet-based remote monitoring further expedites troubleshootingand repairs.

Conclusion. Reasonably priced, commercially available technology can reduceongoing energy, water, and chemistry consumption without sacrificing quality,thus improving the profitability of finishing system operations.

ABOUT JESSUP ENGINEERING

Jessup Engineering is a leading manufacturer of programmable hoist operatedturnkey systems for rack, barrel, basket, and rotating basket parts finishing.With more than 650 machines and 1,300 hoists installed in 42 years, Jessuphas more finishing equipment operating than any single competing machinebuilder. To learn how a Jessup automatic finishing system can benefit you, call248-853-5600 and visit www.jessupengineering.com.

BIO

Timothy J. Kurcz, director of sales for Jessup Engineering, is also responsible for marketand product development. A member of the surface engineering community for 35 years,his experience includes process automation for adhesives, sealants, coatings, electrolyticand electroless plating, fluorescent penetrant inspection, cleaning, passivation, dip-spin,electro-coat, and autophoretic paint coatings. Mr. Kurcz can be reached at 248-853-5600or via e-mail at این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید

ACKNOWLEDGMENTS

Jessup Engineering acknowledges the following companies who providedtechnical input for this article: J. Mark Systems, Inc. of Grand Rapids, Mich.(wastewater treatment systems supplier); and Duall Division of Met-Pro of Owosso, Mich. (ventilation systems supplier)

 CONSIDERATIONS IN THE FINISHING

EQUIPMENT SELECTION PROCESS

ملاحظات لازم در فرآیند انتخاب تجهیزات آبکاری

CJI PROCESS SYSTEMS, SANTA FE SPRINGS, CALIF