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General Mach Discussion / z axis loosing zero
« on: December 06, 2011, 01:21:31 PM »
Ok it started when i was milling a series of letters with a v-tool using V-Carve from Vectric, and i notised that the letters were gradually getting deeper and deeper, first thought the land had shifted so i regrounded it, but the problem was still there... so i made a copy of the G-Code, and isolated one letter, and copied it after eachother so it effectively made a "A" over and over again at the same place, and yes it did very slowly but surely go deeper and deeper every time it made the letter. even if i with all my power tried to pull the z-Axis upwards while it was making the letter i still see the problem.... I do NOT believe its loosing steps mechanically.. i have been running this machine for a long time without problems, and even at half motor current, now I have ramped everything up to max, and i still see the problem...
So the sympton is directly visible as when.
Zero the tool at top of material.
Run multible "A" letters over and over again, and can hear that its grining on each downwards cut which it shouldent..
stop, Place the tool at top of part again, now Mach3 says its 2 mm above the part!!!
I notised that when i slide the FRO override up and down, i can make the problem appear and disappear??
I made a simple G-Code program that just simply excersized the Z-Axis up and down fast for a long time, and that worked flawlessly...
Im using Mach3 to drive the motors, the program that generated the G-Codes was vectric, using the MACH2/3 ATC [mm] postprocessor, i have plenty of power on my motors, and they do not stall, even if i hang on the z axis while its going up. Im using Mach3 3.042. The motor Driver is HobbyCNC product.
I moved the setup to a smaller CNC I have, and run the same program, and I see the same behavior?
Any help is much appriciated...
Best Regards
Kim Mortensen
So the sympton is directly visible as when.
Zero the tool at top of material.
Run multible "A" letters over and over again, and can hear that its grining on each downwards cut which it shouldent..
stop, Place the tool at top of part again, now Mach3 says its 2 mm above the part!!!
I notised that when i slide the FRO override up and down, i can make the problem appear and disappear??
I made a simple G-Code program that just simply excersized the Z-Axis up and down fast for a long time, and that worked flawlessly...
Im using Mach3 to drive the motors, the program that generated the G-Codes was vectric, using the MACH2/3 ATC [mm] postprocessor, i have plenty of power on my motors, and they do not stall, even if i hang on the z axis while its going up. Im using Mach3 3.042. The motor Driver is HobbyCNC product.
I moved the setup to a smaller CNC I have, and run the same program, and I see the same behavior?
Any help is much appriciated...
Best Regards
Kim Mortensen