Sheet cam GRBL torch probe post processor

[Tiger_one]

I'm another JDsGarage builder. Thinking about moving from Fusion360 to SheetCam. I have the OpenBuilds postprocessor working, and tried to import it for SheetCam. Evidently SheetCam does not allow /* or // for comments. So I am either going to edit out all of these (Huge file) and replace // with ";" or find another processor.

Currently I am setup for Z IHS and about to start building THC voltage divider and use some existing software. Probably used relays to flip back and forth from FluidCNC Z control to Arduino THC depending on ARC start.

[devloop]

The post works great except I dislike the slow retract after the touch probe does its touch down, what do I need to do to change that. I don't have a Torch height control, I just want to touch off then go to a height defined in the tools settings, just simple.

[bLouChip]

@devloop - sure, no problem.
which version of scpost are you using? latest is 26.5 here: viewtopic.php?p=31407#p31407
So this info is relative to V 26.5

this is the torch probe cycle for Custom post option "Do you have a THC ?" unchecked or NO.

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; LDC begin per-cut torch touchoff to adjust Z0 
G91  (enter relative distance motion mode)
G38.2 Z-16.810 (probe fast to find sw)
G0 Z3.000 (retract off probe switch)
G04 P0.400 (wait for sw debounce)
G38.2 Z-3.000 F100 (probe slow for accuracy)
G90  (return to absolute distance motion mode)
G92 Z-8.610 (adjust Z0 relative to current Z0 - probeDepth)
G0 Z3.200 X77.884 Y17.543 (goto PH & restore XYA precision) 
M3 S1000 (fire the torch w constant S-PWM)
G04 P0.51 (Plunge travel time: 0.09s, Total PD: 0.6s) 
G1 Z1.700 F1000

Sounds like you don't want this line of gcode ?
G38.2 Z-3.000 F100 (probe slow for accuracy)

If so, there are 3 lines in the scpost that produce that one line of gcode, so perhaps the easiest thing to do is just make it a gcode comment line
like this:

after line# 682 : post.Text("G04 P0.400 (wait for sw debounce)\n")
insert the line: post.Text("; ") -- comment out the following gcode stmt, don't need 2 probe cycles
and before line: post.NonModalNumber(LdcProbeCmd, -PBR * scale, format)

The first torch probe cycle at 1000mm/m speed overruns the probe switch actuation on the floating torch mount by about 0.225mm on my machine. That's OK as long as you account for that overrun distance (on your machine) in the "Floating Torch Mount Travel" distance in the scpost Custom Options dialogue. You have to add it to the actual floating mount travel distance to actuate the probe switch, the sum of those distances is the value for this field. The screen shot is showing 8.61mm in this field now (my machine).
The switch actuator overrun at 100mm/m in the second probe is negligible, that's why its in there. I decreased that retract distance and sped up the second probe from 50 to 100mm/m a few versions back, so you may have the version with the old style 5mm retract and 50mm/m probe speed.

Screenshot 2024-03-03 164026.jpeg (363.16 KiB) Viewed 470 times

[bLouChip]

@devloop- I made a mistake in my previous instruction, you're going to want to remove or comment out more gcode than what I first advised.

These are the gcode stmt lines you want to remove or comment out:

G0 Z3.000 (retract off probe switch)
G04 P0.400 (wait for sw debounce)
G38.2 Z-3.000 F100 (probe slow for accuracy)

You can use the same technique to comment out the gcode stmt as I previously described.
You won't need to replace the delay for sw debounce, the pierce delay will cover that.

[devloop]

Thank you, ended up having to delete all the lines you mentioned including the lines between them. I'm actually running the first post you made, its simple and works, I just changed M7 to M8.

[devloop]

The post is working great and doing exactly what i want it to do. Thermal Dynamics machines need a 2 delay for the first pierce, I played and tried to get it to work but no luck. Possible to set this post up to work with that

[bLouChip]

@devloop-
I added an internal var in OnInit(), LdcFirstPiercePD = 2.0 -- seconds.
It seems to work as I understood you wanted, first pierce is total of 2.0 seconds. I noticed you left (from original version) the code to include the plunge time from PH to CH as a component of pd, so that is effective in the first pierce also.

[devloop]

Appreciate the help, Ive added your lines to my post and still wont delay on the first pierce, what im i missing

[bLouChip]

no worries, you missed a few lines.
I added another condition in this version, to isolate the first pierce logic.
Also, there were some other changes also in the latest scpost you provided, you had changed M7 to M8, and you're using 5.5mm for LdcTorchProbeTravel. These are as they were in this corrected scpost.

[devloop]

Is it possible to take my post and add the touch off to it with the probe, one simple touch off.

[bLouChip]

Try the attached, it produces the following gcode, PH being 3.2mm in the tool, XY being the pierce location.
See the function DoTorchProbeCycle() to make adjustments.

Code: Select all

G0 Z3.2
G38.2 Z-13.0 F1000.0
G92 Z-10.0
G0 Z3.2X113.277Y150.123