Hi everyone,

Playing with Visual Mill - Visual CAM and their Mach3-MM Post, it looks like the Z Axis is being driven in reverse.  When running a 4-Axis roughing program the Z axis will plunge down to -10 then increment itself back to 0.  Does anyone know where I should look to correct this, if this is in fact the problem.  Mach 3, VM, or the VM Post?

Any input will be greatly appreciated.

Will

I do not know how you have set up your machine before trying this program. What should the program do ??

If this is at the beginning of the program, then look at the G Code and try and trace the Z axis movement. I assume your program is written for the z axis to start at 0 or a plus value - say +10 (I assume this is mm). If you ignore this glitch, does the z axis then perform properly.

Two things to look at first. The z axis is plus going up and minus going down. Try this on jogging, and if the jog is correct then that is fine. If your z axis is indeed moving the wrong way. You can alter this by changing the dir pulse to active low (or active high if it is low) - see Ports and Pins/Motor Outputs - or you can reverse the direction of your motor by swapping the leads in either A with A+ or B with B+ coming out of your driver.

The other thing to look for is that you do not, inadvertantly, have an offset programmed into the machine.

If you do not have home switches fitted, or they are not switched on, then set the machine to the position where the program says 0,0,0 is. This, for a mill is normally (but not necessarily) at the bottom left hand corner of the table, with the cutter resting on the work.

Then press the "RefAllHome" button. Check the machine co-ordinates - they should all now be zero. Change to program co-ordinates and change all the DRO's to zero also. Check the offsets by looking at Config/Fixtures ad all the offsets should now be zero.

Move you z axis up to a safe position,  (you can take out the tool while you check) and run your program again. See if it now runs correctly. If it does, try it with the tool in.

If it still goes to -10 and back to 0, look at the GCode program and see if you can identify where it is doing it (or even better - why). It may be that you CAM program  starts with the cutter in a position of say +10 - which it calls 0 - but this should be made clear somewhere in the instructions.