Workflow recommendation? STL object to milled mold.

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Levi Kornelsen
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Workflow recommendation? STL object to milled mold.

Post by Levi Kornelsen »

Using TinkerCAD, I've produced a whole bunch of chess-like pieces over the last few years. I've printed these in resin, turned them into molds of themselves and printed those to cast them in a plaster/concrete mix, and other fun stuff.

Now I'm aiming to make aluminum molds of them to use for plastic injection molding. I've acquired my little desktop CNC, as well as a number of upgrades both already made and on the way, and am currently mucking about with various software (which as of about an hour ago includes FreeCAD), trying to sort out a good workflow for doing this.

I'd be very interested in "Here's how I'd do that" recommendations, if anyone has one!

(For reading level, I'm *very* conversant with TinkerCAD, a few other way of mucking with STLs, resin 3d printing, and such, but am at the "have made a few simple CNC cuts, read the manuals, watched a bunch of YouTube videos" level regarding CNC work.)
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Roy_043
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Re: Workflow recommendation? STL object to milled mold.

Post by Roy_043 »

Move to Path/CAM.
GeneFC
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Re: Workflow recommendation? STL object to milled mold.

Post by GeneFC »

Levi Kornelsen wrote: Tue Mar 28, 2023 7:36 pm
That is a pretty open-ended question, but a couple of comments would apply in almost any case.

* STL is a difficult format to import and turn into a useful solid for further CAM processing. It can be done, but importing a STEP file is likely to result in a much smoother process.

* The general nature of the shapes will determine the suitability for CAM conversion in FreeCAD. If the shapes are highly organic with lots of splines and non-simple curves it could be quite difficult to accomplish very much. If the shapes are more rectangular, circular, etc., then the CAM process could work. The Path WB has some 4th axis capability, but it is a bit limited. It is not possible, for example, to move in all 4 directions at once. This limits surface profiling in many cases.

If you give a bit more detail, including some sketches or photos, it would be helpful.

Gene
Abc12098
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Re: Workflow recommendation? STL object to milled mold.

Post by Abc12098 »

I think I have a similar situation to yours, though I'm wanting to mill parts directly rather than mill negative molds for parts. Hopefully an answer to your question might solve my first post question, or vice-versa.
Levi Kornelsen
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Re: Workflow recommendation? STL object to milled mold.

Post by Levi Kornelsen »

GeneFC wrote: Wed Mar 29, 2023 12:33 pm If you give a bit more detail, including some sketches or photos, it would be helpful.
Sure!

Here are three of the pieces, cast in plaster; there are about 30 different pieces in all:

https://photos.app.goo.gl/5kAbgaAJ1BxhQSpx5

PXL_20230303_233750741.jpg
PXL_20230303_233750741.jpg (185.08 KiB) Viewed 444 times
...

I've managed to get Easel to give me a set of toolpaths for one of these on their free trial by turning a piece into a hole in TinkerCAD and half-embedding it in a block the same size as the work material (same way I made plaster molds), and then importing that and overlaying it on a material, which looks like it should work, but I'd generally rather learn the basics of a skill than pay a monthly subscription...
GeneFC
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Re: Workflow recommendation? STL object to milled mold.

Post by GeneFC »

I took the liberty to add the photo directly to your post.

The following link shows a recent update on the 3D capability.

viewtopic.php?t=75112

Gene
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