Specks and the City: Prototypes & What Clean Means
The following is reprinted with permission from CleanSource, a BFK Solutions LLC newsletter. By Barbara Kanegsberg, BFK Solutions, LLC.
“It’s fabulous when it’s clean.”
“I don’t care that much about how clean it is. It doesn’t have to be all that clean. For me, it doesn’t have to look beautiful.”
There we were, sipping cosmos in that oh-so exclusive and trendy nightspot, in our designer dresses and strappy sandals, surveying the fashionistas. Oh, ok, end of the fleeting fantasy. Actually, I was standing in a manufacturing facility, sipping coffee from a disposable cup, glamorously garbed in comfy jeans and bulky cross-trainers; and, as usual, I was extolling the importance of precision cleaning to a male colleague. My colleague was not convinced in that he builds prototypes; and they do not always look aesthetically lovely.
My colleague has a point. A clean surface does not necessarily look visually beautiful. Sometimes, it does. Certainly, consumer-oriented products often require a particular surface finish on the final product. My colleague pointed out that in the production situations he has seen, technicians would inspect each part or component, rejecting anything with a visible surface blemish. Were these blemishes important?, he wondered. He produces prototypes, and sometimes, they do not look visibly attractive; but they function well enough for immediate evaluation.
Be pro-active with your prototype
A clean surface does not always look visually beautiful. However, starting with the prototype it is important to set up the right precision cleaning processes and to keep an eye on the ultimate goal of production.
It is common to hear that prototypes do not have to be cleaned. This notion is not a mere fashion faux pas, it is a major business error, an error with the potential for serious impacts on productivity, product quality, competitive issue, and that pesky notion of making a profit.
Some justifications to avoid developing a cleaning process for prototypes are:
• We just have to demonstrate that the prototype works. It doesn’t have to work for a long time, so it doesn’t have to be really clean.
• I simply use these little bottles of solvent to clean the part; I hide the bottles in my desk. I hide everything from the Safety/Environmental people; otherwise it’s a hassle.
• Why bother about cleaning? We may not get the contract. We just have to prove the product works, then let someone else worry about manufacturing it.
A clean prototype works better
A little time invested in critical cleaning can make your prototype perform better than the one your competitors are producing. The right critical cleaning surface can help you meet your project goals. This leads to follow-on contracts, job security, and more interesting and innovative projects. In our decades of helping companies develop manufacturing processes, we have seen case after case after case where careful, thorough removal of contamination has resulted in better performance, beginning at the prototype stage. Perhaps an optical coating or heat treatment was more successful. A product with low residue levels tends to function more effectively, to show the physical and chemical properties that your customer or contractor is looking for. The bottom line is that a clean surface tends to work better, even in the short run.
Fleeing from the safety/environmental people is counterproductive
We recommend getting the safety/environmental people involved right away, even if you think of them as “The NO-NO Squad.”
In the short run, it may seem expedient to just spray that hexamethyl death all over the part, then hide the bottle in a corner of the office. Or it may be tempting to pour acetone into an ultrasonic tank and crank up the power (Don’t ever do that! Acetone has a flash point of minus 20 Degrees C, minus 4 degrees F. Do not use acetone near sources of ignition, including ultrasonic equipment.)
There can be unpleasant consequences. In the short run, you might set the place on fire, or harm yourself or your co-workers. It is more productive to use the chemicals required for critical cleaning under well-controlled conditions; that often means involving Safety and Environmental professionals. Setting up processes without the proper permits can lead to costly legal issues for your company.
Another reason is that increasingly, the people paying for the prototype want documentation not only of performance and materials characterization but also of the chemicals and processes. The motivations include product quality, safety/environmental concerns, and reproducibility. Providing your client with written documentation of an inherently unsafe process or of a process using a chemical that is about to be phased out of production is likely to be a negative. Instead, plan processes that keep you, your company, and your customer out of trouble.
Prototypes become Types
What if you actually achieve (gasp!) success? Many companies and contracting agencies give extra points for considering how the product will be produced in quantity.
It is productive to consider how critical cleaning steps might be achieved in routine production. Could an aqueous process be used? Can you lease small-scale production-style cleaning equipment? Have you investigated cleaning processes (cleaning chemistries and cleaning equipment) that might be used in routine production?
Too often, we see cleaning processes that would be totally non-viable in a large-scale production operation used in product development, even in producing product for clinical trials. Gone are the days of tossing the prototype over the fence to Production, leaving the peasants who actually have to produce the product to fend for themselves.
Even if you are an idea person, even if your company only does prototypes, it is reasonable that a prototype with a scale-up plan is a more marketable prototype. S uch a plan should include requirements for and approaches to, critical cleaning, process control, and contamination control.
What Clean Means
Appropriate cleanliness refers to surface quality, surface attributes, and, ultimately, to product performance. A clean surface might, in fact, be aesthetically ugly. Acceptable surface residue is a function of the next step in the process. For example, some parts being prepared for engineered coating require very low levels of organic contamination, but inorganic contamination may be tolerable. In fact, given post-cleaning but pre-coating process steps, visible fingerprints are not always a problem. In one instance, in the course of comparing alternative cleaning processes, an overly enthusiastic associate, one who was not familiar with process requirements, actually cleaned the control or benchmark product that we had supplied. He was very proud of eliminating the fingerprints and smudges. However, an organic-free smudge did not interfere with the process. The control was sufficiently beautiful for the client’s purposes. The time, cost, and potential for re-contamination associated with excess cleaning was not justified. In this case, a beautiful surface could have visible smudges, so long as those smudges had negligible organics.
The point is to understand what “beauty” looks like for your product, particularly at critical stages of assembly. A visibly shiny, polished surface may signal correct cleaning for some. For others, such a surface may signal a poor contact angle or water-break test. Water beads up on a polished surface because of a contaminant, the polishing material itself.
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