GRBL post processing for drilling

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Jimb3893
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GRBL post processing for drilling

Post by Jimb3893 »

Hi FreeCad community. I am a long time CAD designer and CAM programmer. Since retirement I have gotten into wood working with CNC routers. I have two machines with GRBL controllers. GRBL is not capable of canned cycles and so it is necessary to edit the code for drilling operations. This can become tedious and time consuming. I've dabbled in FreeCad for a while and have used it to convert mesh files into solids. I read somewhere that FreeCad has an option to translate drilling code to G1/G0 moves for drilling. I'm still pretty new to FreeCad but I just don't see that option. Is this real or just a rumour? If it is real is there a tutorial for using it?
Many Thanks
Jim Baker
Last edited by Kunda1 on Wed Nov 30, 2022 3:07 am, edited 1 time in total.
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chrisb
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Re: GRBL POST PROCESSOR FOR DRILLING

Post by chrisb »

Hi and welcome to the forum!

When setting up the job, you select grbl postprocessor. If you hover there over the input field "Arguments", you see that there is an additional parameter '--translate_drill'.

I wonder why your grbl cannot understand these. Maybe it is time for a firmware upgrade.
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Jimb3893
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Joined: Tue Nov 29, 2022 2:26 am
Location: Eastern Ontario Canada

Re: GRBL POST PROCESSOR FOR DRILLING

Post by Jimb3893 »

Thanks Chris. Perhaps I don't understand the grbl requirement. I am assuming that grbl doesn't recognize G81 or G83 and will error. So far the posted code from FreeCad includes G81. I did include the "--translate_drill" parameter but then it doesn't successfully post a file. I'm sure I am missing something. I installed 0.20.1 this morning.

Jim
Jimb3893
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Location: Eastern Ontario Canada

Re: GRBL POST PROCESSOR FOR DRILLING

Post by Jimb3893 »

As I expected grbl returns an error on the G81. Now I just have to sort out why FreeCad will not post when I add the translate parameter.
Jim
chrisb
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Re: GRBL POST PROCESSOR FOR DRILLING

Post by chrisb »

Jimb3893 wrote: Tue Nov 29, 2022 3:36 pm I installed 0.20.1 this morning.
It would be best to upgrade directly to 0.21 for two reasons: There have improvements been made to Path workbench. And the internal structure has changed recently. There is a script transforming old jobs to new ones, but I would rather recommend to directly use the new way, just to be future proof.
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spanner888
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Re: GRBL POST PROCESSOR FOR DRILLING

Post by spanner888 »

chrisb wrote: Tue Nov 29, 2022 3:24 pm I wonder why your grbl cannot understand these. Maybe it is time for a firmware upgrade.
The "original" grbl was for 8 bit microcontrollers and the project did a lot of clever work to squeeze in most grbl features, but not canned drill cycles and others mentioned here

While grbl and grblMega are pretty stable, there are some known issues and development has halted. Some sites, eg bCNC, recommend grblHAL which is an evolving firmware for 32bit controllers.

I use the '--translate_drill' recommended above and it works well.

Some gcode senders can also do the conversion for you, for example bCNC.
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Kunda1
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Re: GRBL POST PROCESSOR FOR DRILLING

Post by Kunda1 »

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Jimb3893
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Joined: Tue Nov 29, 2022 2:26 am
Location: Eastern Ontario Canada

Re: GRBL POST PROCESSOR FOR DRILLING

Post by Jimb3893 »

I was able to successfully post grbl flavour code with drill operations translated to G1/G0 commands in FreeCad 0.18.
My only issue now is that it posts in metric even though I have selected inch units in the general preferences. Is there
a units configuration for the "Path" workbench? I don't see it yet.
chrisb
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Re: GRBL POST PROCESSOR FOR DRILLING

Post by chrisb »

Jimb3893 wrote: Wed Nov 30, 2022 2:23 am My only issue now is that it posts in metric even though I have selected inch units in the general preferences. Is there
a units configuration for the "Path" workbench?
Don't use 0.18, use 0.21. And do as told above; now look for --inches.
chrisb wrote: Tue Nov 29, 2022 3:24 pm When setting up the job, you select grbl postprocessor. If you hover there over the input field "Arguments", you see that there is an additional parameter '--translate_drill'.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Jimb3893
Posts: 7
Joined: Tue Nov 29, 2022 2:26 am
Location: Eastern Ontario Canada

Re: GRBL post processing for drilling

Post by Jimb3893 »

Thanks Chrisb. I would gladly update to 21 if I could find the download. The download page shows that 0.20.1 is the current stable version. I downloaded the beta. I got it working. Fabulous!
Last edited by Jimb3893 on Wed Nov 30, 2022 1:29 pm, edited 3 times in total.
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