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Author Topic: Mach not following the CNC code (Axis position lost)  (Read 2241 times)

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Mach not following the CNC code (Axis position lost)
« on: April 05, 2010, 11:05:56 AM »
For the last few months I have been struggling with my red-cam cnc machine. The first issue is that it keeps driving the Z axis down past the G code point. I program it to go G01 4.0 and it heads down until it gets to this point at which time is pauses for a nanosecond and then it continues down until the lower limit is tripped. The funny thing is that it is not repeatable. If I run the program 10 times it might perform it correctly 3 or 4 times.

The second issue is that it seems to loose the x axis position as well. On Thursday I had a student writing his favorite band name on a piece of wood. He created the file on Artcam and brought it in to Mach. When I checked the code on a simulator it worked perfectly but when we ran it on the machine it failed to cut it correctly. Most of the engraving worked well but the final pass shifted ½ to the left and created a type of shadow effect.

I have checked all the connections and I cannot see anything that is obvious. Does anyone have any suggestions as to where I could start to diagnose this? I was thinking about upgrading to the latest version of Mach as I am suspecting that the software is at fault.



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Re: Mach not following the CNC code (Axis position lost)
« Reply #1 on: April 05, 2010, 11:31:15 AM »
Most likely cause is you are losing steps, try cutting accel and Velocity in half and see if it helps. If it does then try increasing again until you have problems then back off a bit.

Also check for any rough or binding in the axis travels as that could also cause you to lose steps if your tuning is near the limit for your motors/drives.

It is not impossible but highly unlikely to be the software unless the DROs show the wrong movement, so keep an eye out for that if it happens again.