Dxf2Gcode newby question...

**Dodgy Geezer** · 04-03-2019

New poster here with a Dxf2Gcode question....

I have just started CNC cutting with an eShapeoko. Very lightweight stuff - cutting balsa sheet and possibly thin ply for the set of model boat plans that I design. I have a lot of plans in Ashlar-Vellum format, which I can get into DXF and then use Dxf2Gcode to create toolpaths. And I have two problems:

1 - the GRBL running on the eShapeoko Arduino controller does not do tool radius correction. At the moment i can minimise the problem with a sub-mm cutter so the error is not great, but I would still like to do things properly. Is there any way to do this with what I have, or do I need to change the controller?

2 - the Dxf2Gcode produces workable G code, but the Z axis goes up and down like a yo-yo. This seems to be an issue with filling in the correct Z axis defaults. Dxf2Gcode has 5 fields for the Z axis - retract depth, slice depth, work origin, safety margin and final depth. There appears to be no explanation of what these do on the net - I filled in likely figures and ended up with a bouncing z axis, which I have to manually edit to get sensible runs. If anyone here uses Dxf2Gcode and knows how to set these properly I would be grateful for a hint....

**Dodgy Geezer** · 18-03-2019

So.... no one uses dfx2gcode then?

In that case, can anyone suggest an open source package that does the same job which DOES come with instructions?

**routerdriver** · 18-03-2019

I don't use the program,but would it solve your problem to offset the shape by the tool radiusand to use the resulting shape for the tool centreline trajectory?

I do use Freecad and find it great I also find it occasionally exasperating.It does deal with tool offsets and allows a variety of tool entry options.

**Dodgy Geezer** · 19-03-2019

Very kind of you to respond!

My problem is that I have many existing plans in Ashlar-Vellum CAD format. I want to use these, rather than redrawing years of work in a different package I'm not familiar with.

In theory G-Code has simple commands for off-setting the cutting line by the tool radius. But I' bought an eShapeoko, which uses an Arduino running GRBL, and that only supports a cut-down set of G-code - no tool radius compensation.

My options seem to be to change the Arduino for a bigger processor which supports a better GRBL set, or find a Cad-G-code interpreter which has compensation.... DXf2Gcode said it supports it - but just seems to add G41/2.

**routerdriver** · 19-03-2019

The G41/2 are doing what they should by appearing.I think you will have to find a way to add the details of the tool you are using to a tool library so it has a figure to work with.I don't use the program myself but I do expect that it needs the information in order to apply the correct amount of compensation.Otherwise the computer wont know whether you are using a 25mm dia tool or a 1mm.

**Dodgy Geezer** · 20-03-2019

I have added the tool radius size. The problem is that the Arduino GRBL does not support G41/2. So Dxf2gcode adds the request for compensation, and Grbl ignores it. GRBL on an Arduino cannot do tool compensation, so it will either have to be done elsewhere before loading the Gcode, or I will need to use a different piece of hardware to drive the mechanics - a Raspberry Pi, perhaps, with a different set of code...