Using FreeCAD + PathWB for Laser cutting workflows

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troyp76
Posts: 32
Joined: Thu May 06, 2021 8:05 am

Using FreeCAD + PathWB for Laser cutting workflows

Post by troyp76 »

Hi all,

I would like to dedicate this thread to exploring using FreeCAD + PathWB for different types of laser cutting (2D / Pipe / Tube).
The goal is to focus on understanding the required laser workflows, how FreeCAD/PathWB supports them today and ways to improve the general user experience.

I have been looking at this for a while now as a way to learn more about PathWB's source code in preparation for contributing.
As time permits I will update this original post with prompt topics and the results of my explorations so far and any initial PR proposals.

If there is interest/advise from others on the subject I will edit this post to capture it as I have seen Russ4262 do for other topics.


Moved video to it's own reply to keep this post clean for future edits.
Last edited by troyp76 on Fri Sep 24, 2021 4:09 pm, edited 1 time in total.
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Petert
Posts: 124
Joined: Tue Dec 01, 2015 9:27 pm

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by Petert »

troyp76 wrote: Wed Sep 22, 2021 4:06 pm
To start things off here is a video showing Path Simulator enhanced with Axis Mapping support.
Still early stages and experimental but quite functional and rewarding to see working. :D

Looks great and thank you for your effort.
I am a refugee from Fusion 360. Switched over to FreeCAD and am spreading the word. After years of very little progress I switched again to another solution. I wish you all the best!
troyp76
Posts: 32
Joined: Thu May 06, 2021 8:05 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by troyp76 »

To start things off here is a video showing Path Simulator enhanced with Axis Mapping support.
Still early stages and experimental but quite functional and rewarding to see working. :D

This model is created using:
- InkScape to convert a BMP to SVG
- Draft WB to convert to a Sketch
- Curves WB Sketch on Surface tool to map the sketch to the pipe’s surface.
- PathWB Engrave operation + AxisMap “Y->A”

Note the existing AxisMap did not work as it assumed the point of rotation was Z0 minus the radius.
AxisMap needed to be enhanced to address this and place the center of rotation at 0,0,0
https://github.com/troyp76/FreeCAD/comm ... bedcb4dc42

Path Simulator then needed to be adapted to rotate the operation's path and solid model.

phpBB [video]


sliptonic wrote: Wed Sep 22, 2021 4:31 pm Oh that is BEAUTIFUL!
Petert wrote: Thu Sep 23, 2021 3:17 pm Looks great and thank you for your effort.
I am glad you both like it and to know that I am not the only one that finds tool path simulation "BEAUTIFUL"! :D
Last edited by troyp76 on Fri Sep 24, 2021 5:08 pm, edited 1 time in total.
troyp76
Posts: 32
Joined: Thu May 06, 2021 8:05 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by troyp76 »

Pipe Cope cutting
This model seems simpler than the previous one but actually required considerably more effort.

- It is based on Part / PartDesign shapes that were Boolean cut together.
- These shapes where then processed to produce a “Normal Cut” so the profiles would represent the cutting action of a 4 axis Tube cutting machine.
(will post more about this later)
- A macro adapted from the forum (posted by Chris_G) to unroll the pipe’s face as a set of wires (minus the seams)
- PathWB Engrave operation + AxisMap “Y->A”

The simulation did not work as expected due to the first G1 “cut off” move not being shown at all.
To address this, code was added to limit a move’s length per update period to be no more than the distance it would travel at the given feed rate.

phpBB [video]
Last edited by troyp76 on Fri Sep 24, 2021 5:10 pm, edited 1 time in total.
troyp76
Posts: 32
Joined: Thu May 06, 2021 8:05 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by troyp76 »

2D cutting

Steps taken:
- Pre-processed an existing DXF file in QCAD
(deleted duplicate and zero length entries, exploded splines into lines and arcs and then simplified the polylines to reduce complexity)
- Imported the DXF as Draft shape then to a Sketch
- Edited the sketch to add tangent constraints on the spiral to ensure it is processed as a single wire.
- Use the sketch validate tool to find and fix open wires
- PathWB Engrave operation

Further development was required to allow G2/G3 commands to be smoothly simulated.
(mostly involved changes the previous changes made to be based on curve parameters rather than assuming the path was in distance units)

phpBB [video]
RatonLaveur
Posts: 991
Joined: Wed Mar 27, 2019 10:45 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by RatonLaveur »

It very much looks like you should be talking to Russ. He works on 4th axis indexing at the moment, I'm sure there are synergies with your pipe simulator.
https://forum.freecadweb.org/memberlist ... le&u=20523
troyp76
Posts: 32
Joined: Thu May 06, 2021 8:05 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by troyp76 »

RatonLaveur wrote: Mon Sep 27, 2021 7:59 pm It very much looks like you should be talking to Russ. He works on 4th axis indexing at the moment, I'm sure there are synergies with your pipe simulator.
https://forum.freecadweb.org/memberlist ... le&u=20523
Yes, good idea.
skal
Posts: 22
Joined: Fri Nov 08, 2019 7:15 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by skal »

Hi all,
else if I'm not as advanced as some others, I'm also trying to create path for laser cutting & engraving, I would like to provide some inputs / questions.
I started from a basic (half) box example (created with laser cut interlocking workbench), with a logo on it:
Box.png
Box.png (58.34 KiB) Viewed 5796 times
It can be then easily flattened (the logo is for now just a clone, not attached to the top part):
Flatten.png
Flatten.png (12.7 KiB) Viewed 5796 times
Therefore, if it sounds pretty easy to create the cutting path by profiling pieces or by engraving, I'm still looking for a solution to handle the engraving of the logo.
The outline of the logo could be easily engraved, and a milling face path could be used to fill in the logo; but in case a real picture is used, I didn't find yet a way to do a kind of grayscale (adjusting laser power) engraving.
Is this something possible ?
troyp76
Posts: 32
Joined: Thu May 06, 2021 8:05 am

Re: Using FreeCAD + PathWB for Laser cutting workflows

Post by troyp76 »

skal wrote: Thu Oct 21, 2021 8:57 am The outline of the logo could be easily engraved, and a milling face path could be used to fill in the logo; but in case a real picture is used, I didn't find yet a way to do a kind of grayscale (adjusting laser power) engraving.
Is this something possible ?
I am not aware of any direct way to do this within FreeCAD.
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