Any plans for Laser/Plasma toolpaths?

[moltenaluminium]

I have a CNC plasma and a laser in my shop. I always have to export my sketches to DXF and use another 2.5D CAM to generate toolpaths. This is quite a pain as any adjustments I need I have to do in the g-code manually, or change in FC, export and repeat which cuts into a lot of my fab time. I love FreeCAD and use it for all of my CAD work now, but this is quite an inconvenience.

Are there any plans in the works to add laser/plasma toolpath generation in FC?

[chrisb]

The jtech postprocessor is for a laser.

[moltenaluminium]

That's cool, but what about operations setup? Can I use the same for plasma?

[Paula]

There was a request a few weeks ago for a post-processor for a Torchmate plasma cutter. I knocked up a version which I think met his requirements. Apparently with the Torchmate the machine's firmware handles the switching on and off of the torch. If your cutter works the same then maybe the post-processor would work for you too. You'll find it attached to the following post:

https://forum.freecadweb.org/viewtopic. ... 48#p496511

[sliptonic]

Can you give details about why existing operations are insufficient for plasma work?

[moltenaluminium]

I have my own built plasma using LinuxCNC as a controller. turning the torch on and off is a simple M03/M05. But what I'm looking for is a proper operation setup that can handle

• kerf width

• pierce delay

• pierce height

• plunge rate

• cut height

Also should be able to do lead in/out as you would see with a non toolbit cutting operation. It would be more advanced, but it would also be nice to have the toolpath generate to minimize thermal distortion while cutting.
Then we may think about multipart nesting but I'd be happy just being able to cut one-of something.

[moltenaluminium]

I may look at how difficult adding all of this would be. I can code python and other languages, but I know nothing about creating tool paths. Any advice is welcomed. Cheers.

[sliptonic]

• kerf width

This is just a matter of configuring a tool. I have a laser cutter and routinely use Path for creating jobs. I have a tool library with a single tool in it to configure the beam kerf. Then I create job templates for the different materials I cut so the tool controllers are pre-configured with power settings and feed rates.

• pierce delay

• pierce height

• plunge rate

• cut height

I don't know enough about plasma cutters to answer. Are these consistent values that could be added to a custom post-processor or do they have to be calculated based on the specific job/operation? There doesn't seem to be anything complicated here.

Also should be able to do lead in/out as you would see with a non toolbit cutting operation.

We have a lead in/out dressup. It could use work but generally meets minimum requirements.

It would be more advanced, but it would also be nice to have the toolpath generate to minimize thermal distortion while cutting.

This is an interesting requirement. I assume you mean we have to not keep a torch in the same area too long. Does that mean leaving off of a long straight cut to go elsewhere and then returning after a period of time or just minimizing cuts in a certain area?

Then we may think about multipart nesting but I'd be happy just being able to cut one-of something.

nesting is a general issue for all users. There are a couple solutions but we need a good nesting library or algorithm. A python re-implementation of deepnest / svgnest is on my wishlist.

[sliptonic]

I may look at how difficult adding all of this would be. I can code python and other languages, but I know nothing about creating tool paths. Any advice is welcomed. Cheers.

Great! I can help bootstrap. Most of the Path devs also hang out on the gitter channel for live chat. https://gitter.im/FreeCAD/Path

[moltenaluminium]

Looks like this was discussed a bit here. Honestly trying to trick freecad into using milling operations is a bit of a hackaround.
Thermal distortion is where cuts are made in a general area to the point that your part and stock turn into a potato chip. It's no longer flat. Proper plasma CAM packages space the cutting out to different parts of the job (if there are multiple cuts) to minimize this.
Also there are considerations like cornering. If you want to make a sharp corner in a cut it is best to do a 270-ish degree loop outside of the part. This allows the corner feature not to melt away due to the torch being too close to the previous cut before it cools.