Mach 3 question

[Michael Simpson Virgina]

I am setup to have A axis slaved to Y axis. I was wandering if there was a way to tweak the A axis by its self? (Even while it is still slaved to Y)

[Mike Heidrick]

This is not in mach and not automatic. You could put your G540 in disable state (break the ground connection to pin 10 with the estop). That will take voltage off all the aixs including the A axis, then you can dial in your A axis carriage position by manually turning the pinion gear by hand (say to a hard stop you know is perfect). Then you can put your G540 in an enable state (just return ground to pin ten by turning and releasing your estop) and all your axis will lock back up.

[Michael Simpson Virgina]

Thanks Mike. That is what I did on the last machine. Its just a little tedious. I just thought that if I could just nudge the A axis one way or another while the Y is locked I could easily and quickly square things up.

Keep in mind I am trying to simplify the method so I can describe it to those building the KRMX02. I have a couple methods in mind. One involves loading a special config file. The other involves writing a special macro.

[Sam Harbold]

From page 37 of the Mach Mill manual

Slaving
On a gantry type miller or router where the two "legs" of the gantry are driven by separate
motors then each motor should be driven by its own axis. Suppose the gantry moves in the
Y direction then axis A should be defined as a linear (i.e. non-rotational) axis and A should
be slaved to Y - see the chapter 5 on Configuring Mach3 for details. Both axes should have
limit and home switches. In normal use both Y and A will be sent exactly the same step and
direction commands by Mach3. When a Reference operation is performed then the axes will
run together until the final part of referencing which is moving just off the home switches.
Here they will move so that each stops the same distance off its own switch. Referencing
will therefore correct any racking (i.e. out of squareness) of the gantry which might have
occurred when the machine is switched off or due to lost steps.

[Michael Simpson Virgina]

Thanks Sam.
That’s exactly what I do on my KRMx01 machine. However on my KRMx02 machine I can not use this method to home. Once the gantry bolts have been tightened there is no flex at all. You need a slight amount for the slave to do its thing. I have to use the option (Home slave with master).

No matter though. I found a way adjust the gantry.


First I loosen all the gantry bolts on both ends of the gantry except one on each end.

I then move the CNC to the 0,0,0 position with my normal mach 3 config settings. I calibrate my Y axis fence along the length of the Y axis.

I then shut down mach 3 and load a custom configuration that has the Y and A running as separate axis. This configuration also has a set of keys setup so I can jog the A axis. The Jog speed is set to 1%.

I disengage the X Rack drive and place an adjustable 48” T-Square against the Y fence, and against a indexing bit in the router. I manually slide the router to the opposite end of the X axis and check the T-square. I then move the A axis until the indexing bit is properly against the square.
I then move back to the 0,0,0 position and start over. I go back and forth adjusting one or the other axis as needed.
Once perfect

[Greg Holt]

That’s exactly what I do on my KRMx01 machine. However on my KRMx02 machine I can not use this method to home. Once the gantry bolts have been tightened there is no flex at all. You need a slight amount for the slave to do its thing. I have to use the option (Home slave with master).

You can still do "Auto Gantry Squaring" with Mach. Use the RefCombination command. This avoids the slaved axis moving individually but still squares the gantry.

Greg

[Michael Simpson Virgina]

Been looking through the manuals for Mach3. Where can I find more information on the RefCombination command?