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The evaluation of cleanliness is often based on a quantification of the particles left on a surface following the conventional or production cleaning process.  The first step in evaluating a part for cleanliness with regard to particles is to harvest those particles that remain after cleaning.  Once harvested, the particles can be counted, weighed, microscopically … Continued

Those of us who have played the particle counting game know that there are some tough calls when it comes to harvesting particles as part of the cleanliness testing procedure.  In some cases, adhering strictly to the specification would result in the rejection of every part tested.  Although I do not believe that rules are … Continued

Before we get into quantifying the particles we have harvested in the last few blogs, I would like to take a minute or two to talk about the specifications that define and govern the evaluation process.  In upcoming blogs we will talk about the quantification of particles in general terms.  In real life, there is … Continued

There are a number of metal finishing process which should be avoided in the manufacture of items subject to demanding specifications with regard to the presence of particles.  These common processes, although employed with the best intent, result in the generation or unavoidable entrapment of particles which may be released under use conditions with potentially … Continued

The test laboratory is a special kind of place.  The work conducted in the laboratory is experimental which usually indicates that we are trying things that have not been tried before to see what happens or doesn’t happen.  Fortunately, at least in the cleaning laboratory, it is not likely that we will initiate an uncontrolled … Continued

Nearly everyone has heard the term “resonance” or “natural frequency” but everybody has a little different idea of what resonance is all about.  In fact, this is understandable because resonance means different things under different situations and there are many different ways to produce resonance. Resonance is the condition that arises when, at a specific frequency … Continued

Resonance, as discussed in a previous blog, can be either or both beneficial and/or detremental.  This blog will explore the beneficial qualities of resonance. Consider the model of a child’s swing discussed in the preceding blog.  We all know that by “pushing” or “pumping” at the right time can easily make the swing go higher and … Continued

A previous blog explored some potentially useful properties of resonance.  The fact that resonance has the power to convert sound wave pressure into mechanical motion can be very useful.  On the other hand, however, the fact that it takes so little effort delivered at the proper frequency to excite resonance also has its “down” side. … Continued

The illustration initially posted in the blog for November 2, 2011 was incorrect.  The acceleration curve had the wrong sign.  The post has been corrected accordingly.  I regret any confusion this error on my part may have caused. –  FJF  –

A dedicated reader has requested that the blog address rinsing in more detail.  Rinsing ranks high on the list of process steps that are often not given their due attention in the specification of an overall cleaning process.  Many specifications just say “rinse” and nothing more.  In fact, rinsing is a secondary cleaning step intended to remove residuals left … Continued