CNC Grinding machine not repeating size - Page 2
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  1. #21
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    Jan 2018
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    We had the scale cleaned and serviced. It was professionally installed by Heidenhein. Servo motor was sent out, inspected and is functioning as it should.

    Please inform what P or I portion of servo tuning is.

    Thanks

  2. #22
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    I hate to sound like a broken record but you should call a local well know machine rebuilder over to check the ways. Member Ballen over in Germany was having issues with his Studer OD Grinder. It's not CNC but he was getting jerking or stick slip. Scroll down to the end of the post where he says it travels like a new machine and no jerking. You could put a long plunger 1" and .0005" indicator (or tenth ) on the work head and tick it forward .0001" at a time and see if all of a sudden it jumps forward. Let the wheel head sit as if you are grinding a part, then test it in several locations. If it does it jumps forward it has stick slip and won't repeat. It may only need what Bruce (Ballen) did and it was to give it new oil pockets. Also check the spindle bearings again. Or have the local rebuilder do it. Your maintenance man is missing something.

    http://www.practicalmachinist.com/vb...-1960s-343863/

    PS: Even if it has Turcite on the ways it can get stick slip. This is not my first rodeo and I have seen stick slip on new CNC machines let alone ones 20 years old. The scraping is to shallow or worn away and the oil can't reach the ways to make a film or wedge of oil. It looks as if oil is wetting the ways too.

  3. #23
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    Mar 2012
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    Could the ossolation be comming from the comp tables not adjusting right. We have a Mikron here and the z axis has a hard time settling in to a position because it keeps trying to compensate for thermal growth. Im talking about .00001 but it never sits still.


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