I had to go in to work last Saturday night to run a hot job for a customer 9pm to 5 am. To get the job done in 8 hours I had to run the same part on two machines at the same time B&S 7-10-7 and a B&S12-22-10 both running 3.7 mr3. After I had completed the run I was compiling a report for the customer from Datapage and noticed a saw tooth in the run chart for the diameter I was checking but the true position looked normal. After identifying the 12-22-10 diameter checks was .1 mm smaller I recalibrated, same result very repeatable .006 mm over 3 parts. Ran the same part 3 times, after recalibrating the 7-10-7, and the turn measured .1 mm larger then the 12-22-10 still repeated with in .006. I confirmed that the 12-22-10 was measuring undersize with a snap gage. I switched tp20 probe body’s, 4mm styli, every thing I could think of that could have possibly made a difference but still had the same result. Both machines were running the same program at the same speed. I had been up for 24 hours so I was getting punchy and figured I would figure out what was wrong with the 12-22-10 this morning. When I got in this morning I put a set disk on the machine that was about the same size as the turn, guess what, it measured with in .004mm of the stamped size on both machines. I did a few more tests before getting pulled to do the next hot job but I could not repeat the .1mm undersize reading. The only thing I can think of that was different was I had the roll up door open more that usual and the temp may have rose a little bit but I cannot believe that it would have made that much difference and if it did it should have effected my true position readings. Any ideas where to look?
Regards,
Terry
Regards,
Terry
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