Expanding G-code library

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19 Jul 2020 08:29 #175124 by jbraun

Could you tell me more about post processors? Is it the post processor that customizes G-code for something like LinuxCNC or UGS or some other control program that will talk to the hardware and tell it what to do?

Yes. The post processor formats the g-code to the dialect(?) used by the control of your choice. Grbl uses the same g-code as Linuxcnc, it just uses a smaller list of commands. A g-code file created for grbl will run on linuxcnc but a g-code file created for linuxcnc may contain contain commands that grbl can't interpret.
I have a small cnc machine running grbl beside my computer at this moment. UGS isn't the control, it feeds lines of g-code to the arduino which has been flashed with grbl. Grbl is the control. In linuxcnc the computer is the control.
That's the best I can describe the concept. Take it fwiw
The following user(s) said Thank You: gerritv, tommylight

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19 Jul 2020 18:17 #175177 by Tango

Could you tell me more about post processors? Is it the post processor that customizes G-code for something like LinuxCNC or UGS or some other control program that will talk to the hardware and tell it what to do?

Yes. The post processor formats the g-code to the dialect(?) used by the control of your choice. Grbl uses the same g-code as Linuxcnc, it just uses a smaller list of commands. A g-code file created for grbl will run on linuxcnc but a g-code file created for linuxcnc may contain contain commands that grbl can't interpret.
I have a small cnc machine running grbl beside my computer at this moment. UGS isn't the control, it feeds lines of g-code to the arduino which has been flashed with grbl. Grbl is the control. In linuxcnc the computer is the control.
That's the best I can describe the concept. Take it fwiw


I got most of what you say and I think you may be saying exactly what I hope you're saying. Let me put it in my own way to see if I have it.

1) If a G-code file is created for Grbl, it can be run on LinuxCNC because Grbl is a subset of what LinuxCNC can do.
2) A G-code file for LinuxCNC MAY run on Grbl, but could crash because the G-code file for LinuxCNC may commands in it that are not part of Grbl.
3) Regarding your CNC system by your computer:
A) If you use UGS, it just sends G-code to the controller and the controller does the work
B) if you use LinuxCNC, it controls the CNC system directly.

If I'm right about 3B, then is your computer connected to the CNC differently when using LinuxCNC than when using Grbl?

It sounds like the model for Grbl is that a program on your computer reads a G-code file, breaks it down and sends the commands to a controller that sends the signals to the CNC mechanical parts. The LinuxCNC model sounds more like LinuxCNC does all the work and sends out signals to the CNC mechanical parts (possible through something else, like a Gecko G540?).

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19 Jul 2020 21:47 #175208 by jbraun

If I'm right about 3B, then is your computer connected to the CNC differently when using LinuxCNC than when using Grbl?

The grbl machine is in my office. It uses bcnc to send to grbl via usb. It's not used for making things, it's a kind of toy.
Linuxcnc runs in my shop connected by parallel port to a G540. That's old-school but still works. Someone else can explain the other possibilities. usb is not one of those options.

It seems you have this figured out now. Don't get hung-up on the "post processor" jargon. After a CAM program creates tool paths it needs to create (post) a text file your control understands. Fancy term for a simple concept.

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19 Jul 2020 23:34 #175216 by Tango

If I'm right about 3B, then is your computer connected to the CNC differently when using LinuxCNC than when using Grbl?

The grbl machine is in my office. It uses bcnc to send to grbl via usb. It's not used for making things, it's a kind of toy.


The problem I'm running into now is that I've found two other devices that might work better for me than my 1st choice. I know one works with UGS, but I'm not sure about the other. I've also had several people tell me about issues with UGS that makes me leery of it. One said it would just stop in the middle of a job and he'd have to hit "Play" to restart it and it's not clear why it stops. Another person told me he had the same issue, plus others - UGS would turn his CNC machine on at random times and there were times it drove the bit down into the wasteboard. So now that's making me concerned about using UGS.

Linuxcnc runs in my shop connected by parallel port to a G540. That's old-school but still works. Someone else can explain the other possibilities. usb is not one of those options.

It seems you have this figured out now. Don't get hung-up on the "post processor" jargon. After a CAM program creates tool paths it needs to create (post) a text file your control understands. Fancy term for a simple concept.


I've also heard people talking about how some CAM programs (like BlenderCAM) don't always generate efficient paths and that it can cost hours if a path is not good. (For instance, one example he gave was of the path not specifying to pick up the bit, but to run it across the surface it's been working on, which slows it down.)

My big concern is what I mentioned above: People with significant issues with UGS. From what little I know, that would mean I'd need to use LinuxCNC instead, which means a parallel interface and, right there that changes a lot of the wiring and what I'd use.

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14 Dec 2022 10:37 #259441 by akg1904
Replied by akg1904 on topic Expanding G-code library
Hi,

I have a post processor that generates G code for Fanuc Controller, can I use same G-code in LinuxCNC.
If not then how can I increase my G-code library in LinuxCNC so that it works with G-code develop for Fanuc Controller

Thanks and Regards
Abhishek

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14 Dec 2022 12:00 #259449 by rodw
Replied by rodw on topic Expanding G-code library
You can look at writing a filter so it converts the fanuc code to linuxcnc code when the gcode files are opened...
It is not easy to add gcodes to the system

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17 Dec 2022 22:30 #259770 by andypugh
Replied by andypugh on topic Expanding G-code library

It is not easy to add gcodes to the system

It's not that hard. If the desired code can be re-spun as a sequence of standard LinuxCNC G/M-codes it it fairly easy. 
If it can't, then it is more trouble, but still very much do-able. 
 

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