This is in response to your request for comments regarding the current issue of IPC-4101.

I only have a couple of issue that presented "hurdles" to overcome when using the new spec.


Item 1. All of the numerical values relating to thickness are in metric. I would like to see both metric and US listed side by side. As of 
           this date all of the existing certs we receive from suppliers still references inches. This has resulted in some confusion when 
           trying to explain why we have to convert stated requirements. This then leads to questions related to defined accuracy for 
           acceptance. For example, in my receiving inspection we inspect for thickness using a standard 1.0" micrometer. We have to 
           convert the tolerances into inches from Table 7. Now I could purchase a metric micrometer but then I would still have to convert 
           the thicknesses on the certs to metric. In any case as you can see and continueus requirement of conversion. This has 
           resulted in a couple of lengthy conversations during ISO audits.

Item 2.  In my opinion there are way to many methods of specifying what material thickness you are ordering. I would prefer to see 
            only one way. Core thickness less cladding as was used in the now obsolete Mil-S-13949.  This eliminates confusion for 
            everyone and simplifies the determination of acceptace. I am looking at that point from a receiving inspectors point of veiw. The 
            less methods an inspector  has to be familiar with the more efficient that inspector becomes. In addition, it lessens the chance 
            of making a mistake.


Just my thoughts and preferences.


Ed Cosper

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