posted 03 July 1998 06:31 AM               

-------snippo------

From: Karri Bost Subject: RE: Calibration/Silvestri/Bost

I have run into a similar issue with injection molding machines in my job. We had a requirement from QS9000 that we interpreted as saying that any piece of measurement equipment that may affect the quality of the product should be maintained and calibrated. We therefore hired a calibration lab to calibrate these temperature and pressure gauges. This in turn doubled our calibration costs. The approach we take to set-up of the injection molding machines is with a set-up sheet (recording temp and pressure), and we found this to be much more reliable from machine to machine once they were all calibrated to a known standard. In the long run of this issue, we have found that the process technicians are spending less time processing to produce a quality product, so the calibration has basically paid for itself.

Once we figured out just what the calibration lab was doing for calibration, we decided that we could maintain calibration ourselves. We are buying a temperature simulator and a pressure deadweight tester. If you hook the temp simulator up to the thermocouple, see if it's reading correctly.