Probing a non conductive workpiece

Help for setting up and using
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CNCBeagle
Posts: 2
Joined: Tue Dec 23, 2014 3:16 pm

Probing a non conductive workpiece

Post by CNCBeagle » Sat May 23, 2020 1:26 pm

In a search of the forum I discovered a couple discussions/requests for methods to use Aoutoleveler with wood or other non conductive materials. It seems that capability may already be in place unless I'm missing something which is often the case. It seems the following workflow might work.

Load your OGF (Original Gcode File)
Create a PFG (Probe File Generator) of the area to be machined.
Run the PFG using some conductive material or block manually moved to the probe points.
Load the resulting RPF (Raw Probe File) into AutolevelerAE (I use LinuxCNC)
Load the OGF
Create the auto leveled file using the combination of the RPF & OGF
Edit the resulting gcode file and change the two G92 Z0 lines to reflect your actual probe block thickness. You may also have to edit the Z clear height to ensure your block will fit.
Run the edited gcode file using the probe block manually inserted under the tool.
Remove the probe equipment and run the rest of the gcode file as is.

I plan to test this workflow later today. I need to cut an O-ring groove in a piece of melamine coated composite. The groove needs to be a constant depth and the combination of my table and the work piece has too much deviation. I thought I would document the workflow here for two reasons. First, for someone to point out where it can be improved and second in case it might help someone else.

I'll report back on my results.

John

CNCBeagle
Posts: 2
Joined: Tue Dec 23, 2014 3:16 pm

Re: Probing a non conductive workpiece

Post by CNCBeagle » Sun May 24, 2020 12:57 pm

It seems to have worked as espected. The maximum depth difference from the RPF file was 0.017" (~0.43mm). The measured difference was more like 0.003" (<0.1mm) which is within my measurement tolerance.

After testing this workflow I discovered there may be an easier way. In AutolevelerAE under options look at "Z Initilization Routine". This option gives you the choice of using the default routine which assumes a probe touch off to zero or your own routine which can use any touch off didtance you choose.

All this may be common knowledge but it was new to me. I will be using AutolevelerAE for more than PCBs in the future.

John

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