The Cost of Not Cleaning
Too often, failures are attributable to inadequately removed contamination.
We’ve heard lots of excuses for not cleaning: There is no money for capital equipment. The workers are too busy fabricating parts. It costs too much to get permits. It costs too much to haul away the process baths. Management doesn’t care about cleaning. Let the customer clean the product; it’s their job. The excuse list goes on and on.
However, experienced manufacturers know that strategic, critical cleaning avoids lost product, saves money and improves reputation. Sure, but is cleaning really necessary? Don’t clean if you don’t have to, but consider the costs of not cleaning. Too often, failures are attributable to inadequately removed contamination. A part that does not meet specifications must be reworked or scrapped.
Rework is a significant cost in manufacturing. There are several aspects of rework costs. There are time, labor and material costs. The unacceptable part must be identified, segregated and sent back for repair or rework. In addition, particularly where surface quality is the problem, additional processes are needed to undo the surface finishing, coating or plating step. Suppose the coating does not adhere or has streaks, spots or bumps that are available below the coating. Many experienced manufacturers find that poor cleaning is associated with such problems. Rework involves removing and then appropriately disposing of the coating. Removing the coating can be a more expensive adventure than applying the coating in the first place. Costs of properly disposing of the coating may not be considered for the manufacturing budget, and they can be significant.
After removing the coating, the steps of surface preparation and coating must be repeated. Let’s consider one definition of insanity: repeating the same failed activity over and over with the expectation of better results. If poor surface finishing is due to inadequate cleaning and surface prep, repeating the inadequate cleaning process may be pointless. In fact, because soil residue has had more time in contact with the surface, surface finishing is even more likely to fail. If a part cannot be economically reworked, it must be scrapped. The costs of producing the defective product are lost. In addition, it costs money to dispose of the scrap.
Failures that the customer finds, and latent failures, are generally more costly than immediate rejects. Inspection protocols to detect product failure are costly; and even with 100% product inspection, defects can be missed. A customer that sees a defect with incoming parts is generally an unhappy customer and may look for a better supplier. A customer that finds a defect only after final assembly is likely to be even more displeased. Latent failure is a worst-case scenario, particularly for high-value product with critical applications. Product failure associated with inadequate or inappropriate cleaning has been observed in areas such as medical devices, commercial aviation, aerospace/military and advanced automotive. These failures may be associated with unacceptable outcomes for the public and for patients. Consequences include litigation, high insurance costs and annihilation of businesses. The solution is an effective, reliable and robust critical cleaning process.
Beyond the issues of product failure, not cleaning reduces competitive advantage. If a cleaning step has no value, eliminate it. If a cleaning step adds value, keep it, but look for ways to make the process more efficient. Evaluate cleaning in terms of overall process flow.
Look at cleaning from the viewpoint of the customer. Increasingly, final assemblers complain about receiving parts that are dripping with heavy machining oils and about the hassle and costs of cleaning. When the supplier avoids cleaning, the tasks of the customer or final assembler will likely be more complicated and more expensive. Because soil becomes more adherent with time, there is a benefit to cleaning as soon as possible after soils are deposited. Overall costs tend to be lower if parts are cleaned by the supplier and the parts are then shipped properly to avoid recontamination.
The right cleaning process is a great sales tool. Customers that receive reliable, clean parts are more likely to return and refer more business to you. On paper, it can sometimes look more practical to avoid cleaning and to ship product as inexpensively as possible. It takes the right perspective and foresight to see that strategic cleaning can result in a positive return on investment by increasing customer satisfaction.
For more information about parts cleaning, visit PM’s Parts Cleaning Zone.
About the Author
Barbara and Ed Kanegsburg
Barbara Kanegsberg, “The Cleaning Lady,” and Ed Kanegsberg, “The Rocket Scientist,” help companies achieve value-added cleaning processes. Contact them at BFK Solutions LLC, 310-459-3614, email@example.com.
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This paper is a peer-reviewed and edited version of a presentation delivered at NASF SUR/FIN 2012 in Las Vegas, Nev., on June 12, 2012.