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
