Post Processor for Bobcam Wire FX20 - G54 vs G92?

tzak said:

How would that look if you used g54 instead of g92, just substitute it?

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tzak said:

I purchased Bobcam wire and it has gone from them telling me they can modify a post processor in a couple weeks, into they can look at it 6-8 week after a month has passed (not pleased). Anyway now I have to modify and change the post on my own. It's not terribly difficult and if anyone has one for a Mitsubishi FX20 that would be great. But one thing I'm trying to understand is what benefits or differences are there to use G92 or G54 in programming for part setup to adjust the post accordingly.

I had a test program with G92 and am wondering what is the best practice. Another shop I know says they only use g92. But when running the test program if I don't set the relative and start points exactly the same then I can just be cutting air as I have since learned.

I have used g54 mostly on the mills it makes a bit more sense to me. If I set a x0 y0 as the corner of my part for example and set that as G54 with the machine move to the correct starting point based on the G54 value.

So if G54 is X0 Y0, and the start of the cut is at x1 y-1 will the machine move there first before starting the cut? If so what should my starting blocks look like?

Thanks

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tzak said:

I wanted to bring this topic back us as I have done some more testing on the machine with regards to setting G54.

I seem to have the post working with the main part of my program looking like so, no sub program.


L100 / TEST G54
(MACHINE MITSUBISHI FX-20 )
G90
G53 G92 X0. Y0.
M20
M78 M78 (Fill Tank)

(2 AXIS ROUGH CUT)
M102
Z1=0.0000
Z2=0.3543
Z5=-0.7087
G00 G90 G54 X-1.2205 Y.15 M91
M80 (Fluid ON)
M82 (Wire ON)
M84 (Machining ON)
E1421 F.160
M90
G01 G41 X-1.2205 Y0. H1=.0081
X-1.2205 Y0.
X-.0197 Y0.


When I move the machine to my part setup I ZERO out my relative position and also make that my G54, (for this example). I can then move the machine anywhere on the table start the job up and the machine will position back to the G54. And the G54 and relative numbers are exactly the same. So the code is doing what it is supposed from what I can understand.

Here is the problem.

I have been setting up my job with a coordinate rotation. Meaning the part is not square in the machine. The machine can calculate this angle and then reset the X an Y to match the new angle making it square for cutting.

When calling up the G53 command at the start of the program with this rotation, the machine thinks the rotation angle is from the machine calibration point (machine 0,0 g53) and is compensating for the angle difference from that point. The further I move away from g53 the larger this number gets between the relative number I what I set ford my G54. If I turn off the rotation then both readouts are correct and the same. If I leave rotation ON the machine does no go to the place I set G54. Now in running jobs I usually use this rotation because I don’t square up parts to the table very often. How can I have the system ignore the rotation based on the g53 from X0 yY0? Having to square up all material is not a realistic option all the time but I'm sure that this can be solved with some G code tweak. Or a way to zero out the g54 to match where the actual X0 Y0 in my program is.

Hope someone can clarify this issue for me.

thanks

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