GRBL post processor

[dh42]

Hello

Your machine is driven through a PC and a "Gcode sender" software or have it's own on-board controller like a 3D printer ?

If it is driven through a PC and a Gcode sender, you can try this plugin to drive the machine.

http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/GRBLmachine.html

++
David

[onekk]

A little word of cautions, many GRBL incarnation, don't use the latest version that is 1.1.

1.1. is different from 0.9 mostly on the controll mechanism between GRBL and the sender.

more problematic is that many cinese implementations, use the old 0.8 or even more old, some old versions have a limitation of 50 character in a gcode line, this limit could be easily reached using too much decimal places in the precision.

Many people have encountered problem due to this behaviour.

Regards

Carlo D.

[pelanj]

Hello, I used CamBam with GRBL post processor and my GRBL bases router successfuly.

I had to make a fresh install on another computer and now I am getting GRBL error 33. I found out it is related to arc tolerances - so I am pretty sure I had this solved long time ago, bit I do not remember how. It must be in the settings, since with the default post processor all is fine. My original settings are lost unfortunately. Are there any default recommended settings? I should have been warned by the Camotics simulation. It did also report errors about arc fittings when I switched to GRBL post processor.

[dh42]

Hello

If you're working with mm, try those values

Maximum Arc Radius = 1000
Minimum Arc Lenght = 0.01

++
David

[pelanj]

Hi David,
these numbers were already in - but I think I found it - the problem was in the number format, I remember reading somewhere that GRBL needs 3 decimals. I copied the number format from the default post processor and no more errors in Camotics. So I think I will be getting no more errors on the machine as well.

[GeoffreyGRoy]

After working with a Chinese-origin 6090 CNC router with a USB-based Mach3 controller for the last 10 years or so I have made the decision to move on.  This move was triggered by a number of problems developing with the controller (including loss of PWM signal to control spindle/laser).  The decision was then to provide a full heart and lung transplant, replacing all the electronics and the spindle, and keeping only the frame, the drive mechanisms, stepper motors and limit switches.

While I could have gone for a new Mach3/4 based system I made the decision to go for a GRBL based controller.  While the GRBL systems provide some limitations on machining options, I made the decision that I could mostly work around these limitations.  The basic GRBL controllers are open source but do have some limitations.  I went for one of the more developed (commercial) options that provides for a 4th axis, hand-held MPG controller, WiFi access and integrated Laser support.  The model chosen was the Nighthawk from CNC3D.com.au.  This controller comes with a companion controller package for a Windows PC: CNC3D Commander.

With the decision made, I turned my attention to better understand the GRBL postprocessor as provided with the CamBam release, and also learning more about how the CamBam Postprocessor system actually works.  I have learnt a lot in this process.  The first task focussed on was the drill MOPs, especially the peck-drill options that I often used with Mach3.  These canned cycles (G81, G82 & G83) are not supported by GRBL.  The provided GRBL postprocessor replaces G81 and G82 with simple G-Code equivalents (no pecking), but pecking requires an iterative process.  To resolve this limitation, I am in the process of:

•   Modifying the base GRBL postprocessor.
•   Developing a post-build executable that will add-to, or modify, the NC file to achieve the required GRBL compatible G-Code.

I have this basic package working for my immediate needs, but I can see that there may be other GRBL users that have identified other needs, or issues, that could be imbeded into a GRBL postprocessor for CamBam.  To get started, therefore, I am releasing my first version (below) for comments and feedback.  I am prepared to look at any suggestions that could improve either the postprocessor or the post-build executable.  I am sure I have missed some useful options that might be included and/or GRBL issues that need to be addressed when producing G-Code from CamBam.

Thanks
Geoff

[Garyhlucas]

As a long time Mach3 user I wanted to add some features to my CNC that was difficult to do.  I went Centroid Acorn which at $363 for the hardware and basic software is a very good deal I think.  Everything is 24vdc, the industrial standard standard so interfacing with sensors or other device is easy.  What I liked is sole source of supply for the hardware and the software. The control software CNC12 has been around for a very long time and is actively supported.  It also has conversational programming so you can get the job done when it doesn't really need CAM.