Millipore Testing – Evaluation by Particle Counting

When it comes to evaluating particle residues remaining on parts after manufacturing, the “go to” is often particle counting.  Particles remaining on parts after normal manufacturing operations are collected using a secondary, more aggressive washing method.  Collected particles are then tallied by size, number and, in some cases, type and probable origin as a measure …

Tape Test for Cleaning Revisited

In a very early blog written in 2011 I talked about the “Scotch” tape test for cleanliness.  At that time I did not address quantification of the results other than as a visual assessment.  In addition to evaluating general cleanliness, this technique is being found particularly applicable when determining the cleanliness of substrates that “shed” …

Gravimetric Contaminant Testing Flow Chart

As I was writing the recent post about gravimetric Millipore testing it occurred to me that I was trying to boil a good-sized part of a 180+ page document into 500 or so words.  It also occurred to me that many people don’t have the time for or interest in reading endless pages of specifications …

Millipore Testing – Gravimetric

Millipore testing is all about evaluating cleanliness based on the presence of particles or other solid, non-soluble contaminants.  In general, it can not be used to detect the presence of hydrocarbons or other contaminants which will be solubilized in the extraction process.  The results of Millipore testing are generally expressed by weight using gravimetric analysis …

Millipore Specifications Update – Extraction and Sample Preparation

“Millipore” testing evaluates cleanliness by extracting particulate contamination from a surface and then either weighing or counting and quantifying the collected particles to assess the cleanliness achieved by a prior cleaning means.  The first step in either case is to collect and prepare for analysis any particulate residue remaining on the surface after pervious cleaning.  …

Millipore Testing – Help!

I just spent a couple of hours re-reading several of the ISO specifications related to “Millipore” testing including ISO16232-3 and -7.   I put the word Millipore in quotes here because although these are normally called Millipore specifications, none of them mentions the word Millipore.  (Millipore happens to be the name of a company that developed …

Millipore Testing – Verification

Millipore testing is a very popular method of measuring and verifying part cleanliness.  The procedure is described in the blog Millipore Testing.  Although the procedures for Millipore testing are usually very well written and precise, there is still occasionally reason to question the results.  So how do you make sure that the numbers are good? Since …

Cleaning Sintered or Porous Parts

Most surfaces that we encounter in industrial cleaning are relatively smooth and contiguous.  We have talked earlier about the difficulties of cleaning blind holes, threads, capillary spaces and other challenging configurations. The one surface we haven’t yet explored is that of a material that is itself porous.  Sintered materials including metal, ceramic, glass, plastic and …

Cleanliness Testing – White Glove and Swab Tests

I have spent considerable time on the blog disclosing and discussing a variety of cleanliness testing methods.  A couple of tests that escaped earlier discussion, however, are the “white glove” test and the closely-related “swab” test.  These tests are conducted by rubbing or wiping a surface using a white (usually cotton) glove or a cotton …