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Author Topic: Setting Z Axis Origin height from the Mill table  (Read 3831 times)

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Setting Z Axis Origin height from the Mill table
« on: May 12, 2008, 09:42:30 PM »
I'm very new to CNC milling and have a very basic question. My Bobcad program generates my Gcode from a Z origin point which is set at the top of the piece I'm cutting. Moving the endmill down into the work is a negative direction in the G code and moving the cutter up is a positive G code direction.

I'm running a Taig mill and operating it with the setup file which came from the vendor.

If I position the face of the endmill on the top surface of the work, and zero the z axis in the Mach 3 software, a negative Z value in the G code moves the tool up not down.  Also a positive G code value moves the end mill down into the work. This is just the opposite direction that I want. I could go into the G code and change the sign of the Z moves but there must be a better way.

Can someone explain the best way to correct this problem?

Any help would be appreciated.


Phoenix, AZ

Offline jimpinder

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Re: Setting Z Axis Origin height from the Mill table
« Reply #1 on: May 13, 2008, 02:20:41 AM »
Simple - flip the "dir" pin on your Z axis to "active low" (or if it on active low, then "unflip" it)

The Z axis should be negative going down and positive going up.

I have no doubt the vendor made the correct connections etc for your mill, but Mach 3 has a lot of configuration still for you to do. You should also check - althougn it appears you have - that your other axis are going it the right direction. This is one of the fundamentals, and a lot of other stuff follows on - i.e. jogging, homing, etc.

Look in Config/Port and Pins.
« Last Edit: May 13, 2008, 02:24:18 AM by jimpinder »
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