In the scenario in Part 1, your boss announced that you should pick out new cleaning equipment because your best customer is complaining about a product contamination problem. You have inspected the current cleaning equipment, the cleaning process, and worked with the operators performing the process. There is no instant “miracle cure;” the equipment needs to be replaced. Keeping an open mind, you considered new critical cleaning processes including solvent cleaning, aqueous cleaning, and so-called “non-chemical” cleaning. You also took into account major company, customer, and regulatory constraints.
After in-house testing and initial communication with vendors, a few promising suppliers of equipment and of cleaning chemistry stand out. In-house pilot testing is not an option. You want to avoid a pro-forma response along the lines of “the test worked great, buy our equipment and chemicals.”
Applications labs can provide valuable information, if you are clear and realistic in your expectations. You must communicate unambiguously and be considerate of the time and efforts required by the applications lab. Choose the vendors you are most likely to work with. Select a few of the most promising processes for evaluation. This is not the time for exhaustive testing on the part of a dozen potential vendors.
Contact the applications laboratory directly, and let the lab know which sales reps or distributors you have been working with. Talk to an analyst, preferably someone with a technical background who will perform the tests. Send the lab a written test plan, go over it with the applications person, and get buy-in. Make sure your plans are realistic in terms of their schedule. If analytical testing will be needed, this is the time to sort out where those tests will be performed and who will pay for them. Get an indication of how soon you can expect results after samples have been submitted. Some cleaning equipment companies restrict the choices in cleaning agents, and not always for technical or performance considerations. They may have business affiliations with chemical suppliers; they may produce or (more likely) “private label” their own cleaning agents. If their business arrangements do not mesh with your technical requirements, consider alternative cleaning equipment vendors.
Decide what parts or components will be supplied for cleaning. You may want to select a few parts that are particularly difficult to clean, perhaps due to materials of construction or configuration. However, if 95% of the product is far more readily cleaned, be sure to include representative, typical product. If certain parts are problematic in that they are prone to damage during cleaning and assembly, arrange for dynamic compatibility studies.1 This means determining materials compatibility under actual process conditions, and testing under somewhat more harsh conditions (i.e. a longer time, a somewhat higher temperature).
Include samples of soil as well as parts that require cleaning. These should reflect actual conditions, such as machining. In some instances, it may be more appropriate to artificially apply the soil and then perhaps heat-age it. This brings up the issue of soil level and soil loading. Be sure that soiled samples reflect actual production conditions, not a “worse than worst case” scenario. Some components manufacturers try to “test” applications laboratories by supplying parts that are coated with soil, often to a level that is orders of magnitude higher than is ever actually seen in production. If you are tempted to do this, try the same test using your current cleaning process; your current process probably will not successfully remove the soil either.
Standards are important; so are controls.2 For example, in any comparison study, it is essential to supply samples of parts that are contaminated in the same manner as those submitted to the applications lab and have been successfully cleaned using your current process. These are sometimes referred to as benchmark samples. For one thing, it assures that the submitted samples could be successfully cleaned in your current method. It provides an indication to the applications lab of what you mean by clean enough. Finally, if there is a suspicion of contamination due to shipping, handling, or environmental exposure, acceptably-cleaned controls provide a benchmark.
Tracking and follow-up
Touch base with the applications lab; make sure that the samples have been received, that tests are running smoothly, and that results will not be delayed.
When you receive the results, do your own assessment. In our experience, some components manufacturers simply accept the statement in a report that samples have been successfully cleaned. Check the details. Were the studies performed as you requested? Was your choice of aqueous cleaning agent or solvent used in the cleaning system? Were the test conditions what you asked for?
Be up-front with your suppliers. Most of us are uncomfortable being the bearer of bad news. If testing was not successful or if the cleaning parameters were not what you asked for, resist the temptation to file the results without further comment. Instead, contact someone in the test lab, preferably by phone so you can have iterative interchange. They may help you to refine your process plans or to run additional tests. You may need to work with them in the future.
Treat your equipment and chemicals suppliers with respect; if you anticipate going with competitive bidding, it is unrealistic to expect a single vendor to bear the burden of testing your product. It is not good business practice to ask one supplier to design the process, perhaps to modify cleaning equipment, and then ignore that supplier in favor of less costly supplier that is only set up to do “build to print.”
Make a decision—you were planning to change that cleaning process, weren’t you? If you were considering more than one process, it is helpful to contact not only the supplier of the successful process but also any other vendors you decided not to select. For one thing, it is considerate of those vendors to not leave them in limbo; again, even from a self-serving standpoint, over the course of time, staying on good terms with those vendors will help your company and your career. In addition, understanding the rationale for selecting one cleaning process over another will enhance product quality, control process costs, minimize regulatory problems, and enhance customer interaction.
1. Kanegsberg, B. and E. Kanegsberg, “Materials Compatibility Basics,” Controlled Environments, July/August 2010.
2. Kanegsberg, B. and E. Kanegsberg, “Standard Philosophy, Part III: Standards and Controls,” Controlled Environments, July 2006.
Barbara Kanegsberg and Ed Kanegsberg (the Cleaning Lady and the Rocket Scientist) are experienced consultants and educators in critical and precision cleaning, surface preparation, and contamination control. Their diverse projects include medical device manufacturing, microelectronics, optics, and aerospace. They are based in Pacific Palisades, Calif. Contact: firstname.lastname@example.org
This article appeared in the June 2014 issue of Controlled Environments.