New project : 5-axis CNC hotwire foam cutter running GRBL

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FlyCAD
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Joined: Mon Mar 08, 2021 3:26 pm

Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by FlyCAD »

Hi,

very nice project.

Since I have also gotten my 4-axis foam cutter back to operation, I was looking for a way to "feed" it using FreeCAD.
I´m using LinuxCNC and therefore also G-Code to drive it.

Apart from your project, this is what I found, probably could be used as input or reference?!

NiCr Workbench by JMG: https://github.com/JMG1/NiCr
Nice interface and simulation, just does not work witch current FreeCAD (0.19) since it´s 5 years old.
Tryed to fix according to error messages but got stuck at some point.
The workbench still integrates and opens, though, so probably this could help with your project?

Foamblade (programmed by a friend of mine): https://sourceforge.net/projects/foamblade/
The version on sourceforge is not the latest, but it would be available...
Probably some ideas regarding synchronising, handling airfoils and automatic block generation can be of interest.

Looking forward to a nice solution for hotwire in FreeCAD!
Willing to contribute, help and test.

Regards
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onekk
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Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by onekk »

I think that link a 3d modeler to a CNC machine is not the best idea in the world.

Let me explain.

Driving a CNC machine is generally a Realtime Task, so it is not a very bright idea to pair with some extensive calculations, that could make the machine freeze when doing tasks.

It is generally a good idea to separate the calculation from driving the machine, plus RAMPS generally have a SD slots, so it is relatively safe to generate the code and write on to the SD card and leave the machine to work.

I have destroyed a and Arduino Mega + Ramps connecting it to the computer, due to some gound loops., and it is not a rare case.

To adapt the Workbench to the new 0.19 I think it is not a impossible task, I think it is not even a bigger task, something is changed in the GUI, but not a totally different things, and the FreeCAD core has been not evolved in a totally different thing.

Regards

Carlo D.
Blog: https://onekk-maker.blogspot.com/

GitHub Page: https://github.com/onekk/freecad-doc with:
  • Introduzione a FreeCAD in Italiano
  • FreeCAD Scripting Guide in English
To contribute see on GitHub
HardRock
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Joined: Tue Mar 13, 2018 5:50 am
Location: Russian Federation

Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by HardRock »

I know NiCr workbench and it "dead" not only because it not works under current FreeCAD versions, it not fits my needs like handle 5-th axis (rotary table), wire on/off, and dynamic wire power management. Also I'm not satisfied with workflow, user experience, and algo for path generation, so thats a reasons for me to create my own set of tools for hotwire.

Simulation is very simple to implement, but this feature just interesting and really not very usefull.

Now I have this objects:
1. Path - Cut movement by curve-curve and point-curve
2. Enter - Move to entry point on safe height and then enter path
3. Exit - same as enter, but reverse direction
4. Rotation - rotate table by given degree
5. Move - Something like path, but offset (X, Z) from point (usually from path endpoint). To make custom paths upon generated.
6. Route - Set of objects above, selected in proper order.

To generate GCODE, you need to select route (or number of routes in needed order) and execute "MakeGCODE" command.
Its good idea to make separate routes for inner cut, outer cut and side cuts, then select them in willing order and make GCODE for CNC.

Now it already allow to simply and predictably create GCODE for parts like that (below). Each part created with one pass, like in 3D printing :)

ImageImageImage

Also photo about how parts feets together :)

Image
onekk wrote: Mon Mar 08, 2021 4:08 pm Let me explain.
You absolutely right.
Stepper motors should be served by separate hardware. As mentioned in theme topic, foam cutter running GRBL on 3D printer board MKS GEN 1.4 (something like RAMPS, but in "professional design" for same money on AliExpress). SD card now not supported, but I plan to modify GRBL to make able to use screen and SD card like a 3D printer firmware.

For sending GCODE to controller, I'm using Candle (https://github.com/Denvi/Candle) it fast, light, and user-friendly relative to most known UGS (Universal Gcode Sender)
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onekk
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Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by onekk »

For a use similar to those you mention, I prefer to use something different, and more taylored for the task.

As the main problem are ground loops, I will avoid them using a SOM (System on Module) or a Raspberry PI, powered from the same power source of the GRBL Board, in this manner there is no risk of ground loops, as they are on the same power line, and if properly taylored they could also run a Linux distribution on It ARM based, so it is easy to have some helpers software on it and even WiFi connection to the machine, to transfer data.

The cost is not too heavy as a Raspberry Pi will cost under 50EUR and an old monitor could be purchased for less than 40 EUR, generally monitors are decent grounded and isolated so "ground loops" are "not too frequent".

I know MKS GEN I own a v1.2 to drive my 3d printer.

Regards

Carlo D.
Blog: https://onekk-maker.blogspot.com/

GitHub Page: https://github.com/onekk/freecad-doc with:
  • Introduzione a FreeCAD in Italiano
  • FreeCAD Scripting Guide in English
To contribute see on GitHub
HardRock
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Joined: Tue Mar 13, 2018 5:50 am
Location: Russian Federation

Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by HardRock »

For me, using RPi or any other signle board computers for driving stepper motors, sounds like overkill and also it do not sovle this task well because linux is not a real time operating system. This like using PRi as controller board for 3D printer... If i do not misunderstood you :)

I dont know why you so afraid about "ground loops". Problem may happent only in case of wrong wiring. For proper wiring - there is no problems.

So i'm using MKS GEN as CNC controller (with own power supply), and my desktop computer, running Ubuntu for creating models and prepare GCODE in FreeCAD, and send gcode over USB to CNC. This like 3D printing over USB.
Of course, RPi may be used to make CNC wireless.
outworld
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Joined: Mon May 10, 2021 1:33 pm

Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by outworld »

Beautiful project !!! i am building something similar, a 5 axis styrofoam cutter, but i am missing how to generate the GCODE.
Can you link the videos, becouse i can't see them?
Have you a site more detailed?
could you give me you mail address so i can send you pictures of my project?
let me know :)
rclemente1989
Posts: 1
Joined: Mon Nov 29, 2021 1:15 am

Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by rclemente1989 »

Good evening !, very interesting project, I am wanting to build a similar machine but with towers, and I wanted to add a turntable to increase the capabilities, is it very difficult to create a Gcode generator in FreeCad? is there any tutorial to see how to start?? since the 250USD that commercial software costs is very far from the possibilities of someone from an underdeveloped country, that money is 2 monthly salaries
HardRock
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Location: Russian Federation

Re: New project : 5-axis CNC hotwire foam cutter running GRBL

Post by HardRock »

No, it's not hard to generate GCODE for 5 axis cutter using freecad.
Above thereis a video with proof how to do it, first version.

Since first version, I had done few improvements in GCODE generator. But I have not published this workbench yet. You can't generate GCODE for hot wire cuter in freecad itself. Additional workbench required.

Now there is 4 different rc airplane models (MiG-3, La-9, IL-2, La-5) in scale 1:7 made by this cutter. Fw-190 in development.
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