[rfresh737]

I'm using the latest Grbl ver 0.9i and I am making 10mm square cuts through 3mm plywood.

Am I able to execute a gcode command that will allow my cuts to compensate for my laser beam width of 0.5mm so my squares actually come out to 10mm square?

Thanks for any help...

[sinha_nsit]

I do not have any idea. But can it be not done using radius compensation, if available?

[pippin88]

This is generally something done in CAM. What CAM software are you using?

[rfresh737]

I'm writing my own gcode actually and sending it to my laser using Universal Gcode Sender. I will look into the radius/tool compensation gcode command.

Thanks...

[cwilkes]

I believe you're looking for G40, G41, and G42. Usually the format is something like "G41 P0.0625" (G41 turns on left compensation [moves your tool to the left of your cutting path by a specified dimension], and P sets the tool "radius"... so half the kerf.) G42 would offset to the right, and G40 would turn off your cutter compensation. As long as you go clockwise around outer perimeters, and counter clockwise around any holes you cut, you can just set a single G41 P(kerf/2) at the beginning of your g-code. (Machines sometimes vary. Make sure to test out your code before cutting anything too pricy)

If you start using CAM software to write your g-code, usually it factors kerf in for you.

[rfresh737]

I believe you're looking for G40, G41, and G42. Usually the format is something like "G41 P0.0625" (G41 turns on left compensation [moves your tool to the left of your cutting path by a specified dimension], and P sets the tool "radius"... so half the kerf.) G42 would offset to the right, and G40 would turn off your cutter compensation. As long as you go clockwise around outer perimeters, and counter clockwise around any holes you cut, you can just set a single G41 P(kerf/2) at the beginning of your g-code. (Machines sometimes vary. Make sure to test out your code before cutting anything too pricy)

If you start using CAM software to write your g-code, usually it factors kerf in for you.

Thank you for the detailed answer...I will give that a try with my Grbl ver 0.9i.

[rfresh737]

I believe you're looking for G40, G41, and G42. Usually the format is something like "G41 P0.0625" (G41 turns on left compensation [moves your tool to the left of your cutting path by a specified dimension], and P sets the tool "radius"... so half the kerf.) G42 would offset to the right, and G40 would turn off your cutter compensation. As long as you go clockwise around outer perimeters, and counter clockwise around any holes you cut, you can just set a single G41 P(kerf/2) at the beginning of your g-code. (Machines sometimes vary. Make sure to test out your code before cutting anything too pricy)

If you start using CAM software to write your g-code, usually it factors kerf in for you.

Rats...G41 isn't supported in Grbl 0.9i and I thought I had read that it was.

I get an error: unsupported command at that G41 line:

G91
G21
G41 P0.50
G01 X0 Y0 F2200
M03 S76
G01 X+00 Y+10 F600
G01 X+10 Y+00 F550
G01 X+00 Y-10 F600
G01 X-10 Y+00 F550
M05 S0
G01 X12 Y0 F2200
M30

[steryd]

it may be defined i n different way.
Usually in milling systems You need first define tool dimmensions (by T and D, H, L commands) and then just choose If You want G41 or G42 (left or right) with no parameters. So try to use it with no parameters and if there won't be error message figure out the way to define tool radius. maybe it,s constant for laser.

[rfresh737]

I confirmed with the Grbl folks that G40, G41 and G42 have not been implemented. They indicated this would probably not be added in the near future as they have more important Gcode to add to their Grbl.

[sinha_nsit]

Then use a drafting software to obtain the offset profile, and machine along it.