EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: t1d on April 01, 2021, 03:02:56 am
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I am DIY'ing an AC Current Limiter. I need a face plate for it. I have drawn the face plate to scale in LibreOffice Draw. I need to convert the file to whatever file format is needed for a CNC machine to cut it out.
I know nothing about CNC...
- What file format do I need for the CNC machine?
- Where can I find a free file converter to convert it over?
I suspect that some intermediary steps may be needed... Such as convert it to PFD and, then, convert the PDF to the CNC format.
If anybody has a CNC and would be willing to cut it out, I would be glad to swap you for something. I have some extra parts for it, if you want to build up your own AC Current Limiter. Or, I have lots of PCB project boards. Or, I am pretty good at KiCad, if you need help with a project.
Metal would be best, of course, but it is expensive. Luan/plywood would also work. But, this plastic board is cheap/$1, cuts easily and is easily sourced:
https://www.dollartree.com/cooking-concepts-dual-sided-cutting-boards-8x11-in/300767 (https://www.dollartree.com/cooking-concepts-dual-sided-cutting-boards-8x11-in/300767)
I have attached a rough draft of the face plate; I am still tweaking it a bit. And, I would need to remove everything that is not to be cut.
Thank you for your help!
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What we want for CNC be it Laser or Engraved/Routed is a Vector format not a Raster format like Libre Office produces. So SVG or DXF would be the two most common options.
For my own Laser Cutting I use Fusion 360 and even though it is 3D modelling software getting a 2D face out of it in DXF format to process for my Laser is easy. In my case my Laser speaks SVG so I run it through Inkscape for that and save it as an SVG. Generally PDF is not used as a format.
So for your Libre Office file try this. Install Inkscape as it is free :-+ and export your Libre file as EPS and then use Inkscape to save as DXF or SVG depending on who or what is doing your CNC job. Still won't be perfect but it could then be tweaked into shape by others for $.
Personally I would start again in a more CAD (vector) based environment some freebies include :
Libre CAD (clunky but works) https://librecad.org/ (https://librecad.org/)
Inkscape (not ideal for CAD but it will produce a vector format and a whole lot more) https://inkscape.org/ (https://inkscape.org/)
Fusion 360 Hobby License (steep learning curve but worth it for lots of things including PCB's) https://www.autodesk.com.au/products/fusion-360/personal (https://www.autodesk.com.au/products/fusion-360/personal)
Any of these will get the format others will need for a good job back.
With Lasers most will have Ply or Acrylic to 8mm should be fine generally I run 3-5mm for faceplates. If you want Aluminum or Steel then CNC Routing in a hobby machine or you will be looking for the more industrial Lasers or Water Jet Cutting.
Could also be 3D printed but embossed engraving is a bit limited.
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Thanks, Bean, this is exactly the info I needed!
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I'd think that 80% of your faceplate is in designing in where you want all your stuff to go, and 20% or less is in the drawing of the stuff itself.
I would probably not bother to convert your drawing, but re-create it in some CAD program.
I find those web based subscription models abhorrent and quite some years ago I switched to fully Open Source out of principles.
FreeCAD is also a quite powerful 3D CAD program. Recently 0.19 has been released recently, and there are still some valid reasons why the version has not reached V1.0 yet.
But you only need a simple 2D CAD program.
.DXF is indeed a common format (but in lots of dialects & variants) that can be used to exchange vector graphics between different programs. I once had interest in LibreCAD, but it was too buggy and development was too slow so I abandoned it. But more so because my interest lay more in 3D CAD and LibreCAD only does 2D. LibreCAD was forked from Qcad. It has both an "open" and a commercial (EUR33) version. But I'd guess that the windoze market is flooded with simple 2D CAD programs.
And indeed: .SVG is also a usable format as a start to get some CNC done.
I've got a small CNC machine which runs GRBL, and I use bCNC to control it. bCNC can read .svg and .dxf files (and G-code and some others) and it can also do some processing to 2D graphic files such as adding tool offsets to contours, lead-in and lead-out for toolpaths and adding tabs. It's not a very sophisticated program, but it does what it does well enough.
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Create the full scale drawing with a CAD program - I use a free version of AutoCAD. I'm not sure it is still available but any decent CAD program will output a .dxf file.
Run the CAD .dxf file through a CAM program to set up the cutting parameters - I use CAMBam
Take the gcode output of the CAM program and feed it into the hardware's stepper driver. I use Mach3
http://www.cambam.info/ (http://www.cambam.info/)
https://www.machsupport.com/ (https://www.machsupport.com/)
The CAM part is where the rubber hits the road. You need to think in terms of drill diameters, cutting various circles for meters and so on. Not hard but time consuming.
I built the attached panel using clear acrylic sheets. There are two panels machined together and they sandwich a paper copy of the CAD drawing.
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https://www.frontpanelexpress.com/front-panel-designer (https://www.frontpanelexpress.com/front-panel-designer) might be a lighter install than a full-fledged 3D CAD suite. I have used it for mockups, but haven't (yet) sent anything to production. It will export into DFX, SVG, PDF, & STEP ,too.
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One of the advantages in modelling in a 3D environment is it opens up more flexibility and options for manufacturing. This simple panel below is from my Laser which I used to make it on in this case ;)
Part of what I was doing at the time (and still am) is learning how to model items to fit into a project. The switches in this case are a cheap rocker from evilbay so they don't exist as a CAD model but now I have them added to my library for later use. Same thing goes for the Panel meters. Neither are full models they are dimensionally accurate 'place holders' to design around.
This panel model could have been sent off to my Tame waterjet cutter for Aluminium or Steel cutting as is or in this case exported to Inkscape for some colours and fills so the Laser knows what to cut and engrave. Or in this case with the bold typeface could also have been direct exported to my 3D Printers slicing program and printed face down for a gloss finish.
Example shots for references and ideas. 3D printed case for my TS100 is just an example of embossed printing, printed face down on glass on my CR10 so within 'limits' it is still a good home process for panels.
There is no one right bit of software for this sort of job just find the one that suits you best or have a serious think about what might suit later and learn how to drive it better.
(https://www.eevblog.com/forum/3d-printing/3d-printer-yet/?action=dlattach;attach=544250;image)
(https://www.eevblog.com/forum/beginners/helpinfo-with-cncing-a-face-plate-for-an-ac-current-limter-dim-bulb-tester/?action=dlattach;attach=1207328;image)
(https://www.eevblog.com/forum/mechanical-engineering/40w-300x200mm-laser-cutter-engraver-vollerun/?action=dlattach;attach=755436;image)
(https://www.eevblog.com/forum/mechanical-engineering/40w-300x200mm-laser-cutter-engraver-vollerun/?action=dlattach;attach=755442;image)
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Thanks to all of you, for your very excellent input and effort to reply. I am thinking that FreeCAD may be the way to go, because, IIUC, it interfaces with KiCad. And, I am fairly fluent in KiCad.