Cleaning – When Things Go Wrong continued

As I said earlier, the cleaning equipment itself is often not the source of what is perceived to be a “cleaning” problem.  It is understandable, however, that blame often falls on the cleaning process as it is during the cleaning process that the problem often first manifests itself.  Once a problem is detected, the solution to the problem can follow one of many scenarios.

First, let’s assume that there is a deficiency in the cleaning process.  The logical thing to do is fix that problem.  Diagnosis of the health of a cleaning system is not that difficult for someone familiar with its operation and can often be accomplished without on site help from the manufacturer.

The next logical scenario is that something upstream of the cleaning process has changed making the parts more difficult (or impossible) to clean.  What might cause this?  The culprit, maddeningly, can be just about anything that precedes the cleaning step which, of course, is just about everything else since cleaning is typically the last step in the manufacturing process.  Sometimes the defect provides its own clues to its source.  For example, the contaminant may be identifiable as something used in the manufacturing process.  The pattern or location of the contaminant may also be the “smoking gun” as one backtracks through the manufacturing process.  I have even seen cases where the problem is something not even related to the manufacturing process but, rather, something like grease used to lubricate a conveyor on which the parts travel.

This is where the “Perry Mason” part of the investigation starts.  It involves backtracking through the manufacturing process and asking knowledgeable people at each step in the process what, if any, changes have been implemented in their part of the manufacturing process recently.  Changes in tooling, materials, lubricants, temperatures, abrasives, material handling procedures etc. are all potentially significant.  ANY change, no matter how seemingly trivial, may lead to a parts cleaning problem at the end of the line.  This search should also extend to suppliers who supply raw parts and materials as processes and procedures may vary from supplier to supplier or even in product coming from the same supplier at different times despite the tightest QC procedures and specifications.  Granted, this can be a lengthy process but in the end one that sometimes provides extremely valuable information which also may be of benefit beyond solution of the immediate cleaning problem.

Once (if) the source of the contaminant or change is found there are two immediate responses.  The first, and probably best, response is to either eliminate the source of the offending contaminant or change the offending process.  In all likelihood, anything that complicates the cleaning process is probably not good for the overall manufacturing process unless, of course, there are no alternatives.  The second response, and one that may be somewhat more complicated, is to change the cleaning process to accommodate the “new” contaminant.  If you are lucky, this might only require a change in the cleaning chemistry, a change in the cleaning process using existing hardware (time, temperature and agitation).  At worst, completely new cleaning hardware may be required – a time-consuming and potentially costly solution.

Remember, cleaning is only one part of the overall manufacturing process and can not necessarily fix problems originating earlier.  Every effort should be made to control not only the cleaning process but everything that precedes it.  I enjoy troubleshooting but would rather not have to do it!

–  FJF  –

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