Grbl mastercam post

Couldn’t think of a good way to share this, but this might help.


There are a couple of other things to be careful of:
M6 - Grbl doesn’t like it, but some senders will intercept it and allow for tool changes.
G28 - always a mess for new users that haven’t set a G28 location.

If you modify the code as above, does it do as you expect?
Remember, you’re going to have to do the things that other machines do themselves (i.e. Set zeros, handle tool length offsets, etc)

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Thank you, I will try it after work.

Still no luck, if someone could post a simple .5 x.5 square cutting the outside contour and a .5 diameter circle cutting the outside contour and post working codes in Candle and in inches, that might help me. There are a lot of little things I can lose easily that error out, but arcs are trouble for sure. Thank you all.

The arc errors are usually an issue with precision in the arc calculation. Many times this can be fixed by simply using metric. If you really want to export in inches for some reason, is there a way to increase the precision (more decimal places)?

Yes I can, a comment I read said arcs need to be linearized, whatever that means and not sure how to do that.

That’s only if you’re using Easel to send the gcode. Grbl will convert your G2 and G3 arcs on the fly. The problem is that your arcs aren’t precise enough for GRBL’s checks.
Try running your arc filled project in metric (mm are more precise than inches). I’d assume MasterCam has a precision setting.

Mastercam has a tool that turns removes splines, I ran that and got a good toolpath after cleaning up the program. Thank you for all of the help. Stepper questions next. My control was set at $100-$400 $101-$400 $102-$400 and my .5x.5 square came out at .64x.64. I changed them all to .$200 and it cut the same size.

Can you post all of your grbl settings?

openbuilds grlb settings…txt (1.7 KB)
Here you go.

I did notice that my $200 changes didn’t stay. So I will run it tomorrow after a reset.

I was guessing that. :wink:

Changing your settings by half will change your motion by half… Was that your intent?

.5 (expected) / .64 (actual) * 400 (current steps/mm) = 312.5

so my profile was .160 too big on x and y at $400 settings, so do I change them to $380?. Thank you again for the help.

Just to be clear…you are changing the $100, $101, and $102 settings?
The actual values won’t have the $

So you might send, for the Y axis, $101 = 320

To get the value:
Expected dimension / Actual measurement ***** current steps/mm

If you designed a 1/2" square and measured a 0.66" square, and your current $101 value is 400, it would calculate as:
0.5 / 0.66 * 400 = 303.03
You would enter $101 = 303.03

Yes thank you. I will try it later. Have a great day.

That worked perfect. Thank you and have a great day.

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