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Author Topic: How to zero both program and machine coordinates after moving Z-Axis?  (Read 3104 times)

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On my CNC router, the home switch for the Z-Axis is at the top. After clicking "Ref All Home" button, I move the Z-Axis so that the router bit touches the workpiece and zero the program coordinates. If a project requires two or more router bits, I have to reset the Z-Axis. Sometimes, the depth of cut is wrong. Let's say that I run a program to do pocket cuts at 1/4" using 1/8" router bit and then run another program to do profile cuts at 3/4" using 1/4" router bit. Even after moving the Z-Axis so that the router bit touches the workpiece and zeroing the program coordinates, the profile cuts are 11/16" deep instead of 3/4" deep. I can't zero the machine coordinates after changing router bits. How do I zero both program and machine coordinates after changing router bits and moving Z-Axis?

Offline Hood

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You dont want to zero machine coords other than when homing. If you are zeroing the work offsets correctly with the new tool then it should be correct, only thing I can think of is maybe you are calling a height offset which is in the tooltable.
Hood
I didn't set up tool tables for different router bits because my CNC router doesn't have automatic tool changer. When I have to change router bits, I have to raise the Z-Axis, change bits, lower Z-Axis until the bit touches the workpiece, and zero Z-Axis coords. I assume that the machine coords are wrong for different bits. How can I fix this?

Offline Hood

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Machine coords stay the same no matter what you do to work offsets. You are doing it the correct way and if there are definitely no offsets in your tool table then possibly your code is calling a different work offset for the next tool.
Hood

Offline ger21

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I assume that the machine coords are wrong for different bits. How can I fix this?

No, you're just not zeroing the Z axis to the same spot. Try using an auto zero plate, it will be much more accurate.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
I read the manual and I'm not sure if I can enable "Remove Tool Offset" in "Pgm End or M30 or Rewind" part of "General Logic Configuration" dialog box or "Tool Offset On/Off" in "Offsets" screen.