[scriptster]

Hi everyone!
Not a complete newbie but new to the particular task at hand.

I've been doing some very light duty laser cutting (craft foam with 200mW laser diode - http://elabz.com/laser-cutting-diy/ ) and the development process goes something like this:

1. Draw it in Inkscape
2. Save the final shape in DXF R12 format
3. Convert it to GCode using DXF2GCODE
4. Cut it using EMC2

note: everything's done in Linux,

it's the Convert it to GCode using DXF2GCODE part I'm having a problem with. DXF2GCODE is a wonderful program but it does not really care about the sequence of cutting the shapes. Since you cannot cut the outer shape before the inner ones, I have to manually re-shuffle the shapes and move the outer ones towards the end of the file. Very tedious process.

I have written a simple PHP script that moves shapes around in the GCODE file and puts the largest ones at the very end of the file. Will be happy to share the script it if anyone needs it. But it has limitations - the "largest" means more lines of code - just as simple as that - and this approach can backfire spectacularly if your outer shape is a large but simple square.

Anyways, rant aside, can someone recommend a Linux software that would do DXF (or SVG) conversion to GCODE while keeping track of the nestled shapes so when I run the code it always cuts the inner shapes first?

Thanks!

[marcelg]

I also use linux but have never used DXF2GCODE.

That being said, you could use camexpert (www.qcad.org/camexpert_downloads.html) to convert your DXF file to GCODE. It has the ability to optimize the path.

One small note: camexpert is not open source but it is cheap. I think I paid $150.00 for it. You can download the trial version which times out after a few minutes.

[dewme5]

Look into sheetcam as well. There is a linux version, and the trial will output 180 lines of code.

[kritzler]

Try SimplyCam
(MR Soft software tools) a windows program, runs under linux (about 75.--$), free trial version available.
kritzler

[kritzler]

Try SimplyCam
(MR Soft software tools) a windows program, runs under linux (about 75.--$), free trial version available.
kritzler

[scriptster]

Try SimplyCam
... runs under linux...

Do you mean, Win version runs under Wine? I couldn't see any Linux-related info anywhere on the site.

By the way, it's been a while since I posted this but I've yet to settle on a good way to treat the sequential cutting of nestled shapes. Does anyone know if the feature I'm looking for has a standard or customary name?

In other words, when I'm looking for a description of another CAM software that looks promising, what feature name am I looking for? No one seems to call this "sequential cutting of nestled shapes" which, I admit, is a mouthful. What else do they call this? It seems such a common issue in plasma and laser cutting ...

[kritzler]

Hello Scripster
Yes, Simplycam runs under wine. I tried another program, works in the same way: Cut2D (Vectric). You can set little bridges by mouseclick, good preview, good customizing.
>"so when I run the code it always cuts the inner shapes first?"
In both of these programs you can fix the order of the cuts: inner cuts first.
Have a nice day!
kritzler

[fishface]

Hi scripster; are you still using dxf2gcode?
Although a brilliant program, I too got fed up with re-ordering the cutting order in a text editor. I decided to modify dxf2gcode to that you can now select the shapes that you want cutting last, then right click and select 'cut these shapes last'. When you 'write gcode' it then does it in two passes; first, everything that you did not select as 'cut last', then everything that you did select as cut last. It's a bit of a hack because I haven't updated everything, for instance it doesn't show the two separate cutting orders on the screen, but it does generate the gcode in the requested order which is the important thing. I'm happy to share if anyone else could use it.

[victorofga]

long time i used ace converter by dakengineering.. they are the turbocnc..

DAK Engineering - Ace Converter

[scriptster]

Hi scripster; are you still using dxf2gcode?
Although a brilliant program, I too got fed up with re-ordering the cutting order in a text editor. I decided to modify dxf2gcode to that you can now select the shapes that you want cutting last, then right click and select 'cut these shapes last'. When you 'write gcode' it then does it in two passes; first, everything that you did not select as 'cut last', then everything that you did select as cut last. It's a bit of a hack because I haven't updated everything, for instance it doesn't show the two separate cutting orders on the screen, but it does generate the gcode in the requested order which is the important thing. I'm happy to share if anyone else could use it.

Thank you for the suggestion, fishface, and yes, I would love to see the modified version. In fact, I have been doing (or tried to, anyhow) something similar but manually - select internal cuts first, export only those, then select the rest, export them in a separate file and then combine in a text editor. Problem is: it's a very tedious work and also, the shapes I was cutting ( CNC Files - Electronics Blog ) tended to have shapes within shapes within shapes within shapes ... Because of the particular space limitations (long story) I have to pack them as tightly as I can and that just exacerbates the problem.

Last couple of my models I designed in Inkscape and converted to Gcode using the Laser Engraver Extension ( http://www.slackersdelight.com/instr...erengraver.zip ). As the name implies, the export extension also did not care much about sequence of cuts but it turned out that if exported shapes in the order of their IDs in Inkscape. So, I also had to "hack" the process, so to speak, by numbering the internal shapes first, the external - last, and that took care of the inclusions. Still a lot of tedious work because you tend to create larger (external) shapes first and so you're almost guaranteed to have to renumber them all in the end, but it worked for me (to a degree - some finessing of the Gcode in a text editor was still needed).

I haven't had much time to play with this lately, and since I've done it last, Inkscape has come up with the new version of the program which now comes with a stock extension called InkCut V1.0 . I haven't had a chance to try it yet, I sincerely hope it may finally take sequence into account given that there's the word "Cut" in the name Has anyone used the Inkscape/InkCut pair for laser cutting yet?

Cheers!

[fishface]

It's based on version B02 from Downloads - dxf2gcode - A program to convert a dxf drawing into G-Code - Google Project Hosting, so get that version first, then once you've installed it, configured it and got it working, try overwriting dxf2gcode_b02.py with the one I've attached.
Usage:
Load a DXF
Select what you want cutting last (shift select for multiple selections), then right-click and select 'cut last' from the pop up menu.
Then 'write gcode'. The algorithm for calculating the best route for cutting will still include the ones that you want cutting last, but when it comes to write to the gcode file, it does it in two goes. First the 'not cut last' shapes, then the 'cut last' shapes.
It's all a bit of a hack, but it does work.

[fishface]

Another little tip if you still need to manually edit the gcode files from dxf2gcode:
I changed the following line in the preprocessor config file:

rap_pos_plane = %nl(#########################)%nlG0 X%XE Y%YE%nl

which basically introduces a blank line, then a load of ######## before each G0 X Y line. This makes it really easy to find the start of the gcode for each different shape.

[scriptster]

Thank you, fishface, I'll be sure to give it a try!

Have you tried to contact the original authors of dxf2gcode to make your changes a part of the "official" distribution? I think it's a feature definitely worth having!
Cheers!
:cheers:

[fishface]

Yes; I emailed them asking if they had any plans to implement it before I started. I didn't get a response so did it myself. It would be good if they would adopt this functionality as more people could benefit from it, and it would be done correctly (rather than my hack).

[fishface]

Quick update; I've modified it so that you can select shapes, then right click, then select either 'cut first' or 'cut last'. This means that any shape can be put into any one of three groups: 'cut first' (use for inner most shapes), 'neither cut first nor last' (ie you haven't selected either of the other two options), or 'cut last' (use for the largest outermost shapes)
See my previous post for details of how to install. Again, it's just a hack, but it works.