Hi all.
I'm new on this forum , then sorry if give same question .. but..

I have 3 axis CNC machine (self made) and have some mechanical error , and want solve this problem with
software: Formula Axis Correction
I genetare formula for Z axis : Z = Z+(2*10^-6*X^2-0,0007*X+0,0016) , and if test it with button Test , then on result give me value what I expected.
But If try it in real movement then move still same . This formula make small correction +-0.05mm.
But not working :

Mach 3 version : R2.63
CNC controll board : USB BSMCE04U

Is possible do it with this control board ?
I enable : Formulas Enabled

regards.

Hi,
the formula correction is and always has been patchy. Sometimes mach correctly applies the formula but at other times it does not.
I was never able to get it to work consistently enough to use. Given that all Mach3 development ceased seven-eight years ago it will never be fixed.

Craig

Thanks for your post , understand.

Hi again ..
Is there any gcode trasformation before execute it ?
using VBasic script editor or different way .. .
I see so there is possible edit button , make script for M code .
Is possible read gcode (loaded gcode from file) line by line and
make transformation. Or is possible manage path planner?

My idea is to read line by line , and recalculate it , transform , and get back , or generate more shorter gcode's and send to path planner.
I don't know how it working .. but just ide .. .

regards.

 

Hi,
I had a procedure that did just exactly that, which I used for some time on certain jobs. At that time my axes were out of square to the tune of 0.3mm per 100mm.
Using formula correction in Mach3 did not work because the correction is applied 'in a lump' at certain times and that in turn caused what amounts to an infinite acceleration
and therefore the machine would stall.

To counter this I wrote a script, note by this time I was using Mach4, so the script was in Lua to apply the correction. This was possible because the Gcode programs I was using were all
linear moves in X and Y, and my scheme would not have worked if there were any arc moves, namely g2 or g3 moves. Provided your Gcode includes no arc moves you could do as
you have proposed, although the extra layer of complexity becomes very tiresome and correcting the machine fault is still the best option.

The procedure was run the script over the Gcode program and the script would write a new 'corrected' Gcode program where the X and Y ordinates had been corrected a little to
accommodate that they were not square to each other, and then run the 'corrected' Gcode file as opposed to the raw file.

I have since built a new machine where the axes are square and no such correction is required.

Craig

Hi Craig.
Yes, but it is possible to do it internally in Mach3 or Mach4?
I have many python script for gcode transformation, and there exist many utilities for G2/G3 to G1 convert..
For example, make a new plugin to do it..

Hi,

Yes, but it is possible to do it internally in Mach3 or Mach4?

Its been nine years since I've used Mach3 so I'm just not going to bother trying to answer that.....but it does work with Mach4, but not in the way you are thinking about.

You want to commit the job to Mach4 and have it apply a formula correction, and to my knowledge that won't work. In fact there is NO Formula correction feature in Mach4,
I presume because there is no way to have it work consistently without the correction being applied in a lump with the same problem that Mach3 had. My procedure
was to pre-process the Gcode file. That I used Mach4 and Lua to do that is just happy circumstance....you could pre-process a file using a Python program just as easily.

Craig

OK.
Understand ..