Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: jagert59 on January 29, 2010, 02:55:23 AM
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I am having trouble with my mill, it seems that I am losing steps. The mill is set up as per my signature.
I am using an indicator mounted in the spindle, I zero out the indicator on a bar clamped to the table parallel to the Y axis, making sure to remove any possible backlash. I then make a G1 move in the X axis of -2.953" (75mm) and then insert a 75mm Jo block. With the feed rate set to 4 IPM the indicator reads .000. I then remove the backlash and rezero my indicator on the Jo block, remove the block and make a g1 move in the X axis back to 0. The indicator will read -.0015. I did this 3 time at this feed rate and had the same results. When I increase the feed rate to 6 IPM, I get an indicator reading of -.001 on th first negative X axis move, but it is off --.035" on the move back to 0. If I increase the feedrate to 10 IPM I get -.006" on the negative move and -.067" on the move back to 0. If I do a G0 move it is off almost -.185" on the move back to 0.
I've do some limited testing in the Y and Z axis and don't seem to have any issue, the indicator reads within .0005" both directions.
Any idea what might be happening?
Thanks
Tom
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Check that you have no loose pulleys, failing that I can only think it is a problem with tuning or a drive.
Hood
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How are you 'removing backlash'? Sounds to me like you have a problem with your testing proceedure.
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Check that you have no loose pulleys, failing that I can only think it is a problem with tuning or a drive.
Hood
Checked the encoder attachment set screws they were ok, no pulleys it's direct drive, swapped drive with the Y axis drive, no change. could I have a defective encoder, I have another one, would it make sense to swap it?
Tom
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How are you 'removing backlash'? Sounds to me like you have a problem with your testing proceedure.
By 'removing backlash', I meant that I made a small move in the opposite direction to 'take up" the backlash ~.0015" that the X axis has. I did this so that the backlash wouldn't effect my measurements.
Tom