Generate pocket toolpath from heightmap

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oaktree
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Generate pocket toolpath from heightmap

Post by oaktree »

This is my first post to this forum, so thanks in advance for your patience!

I am an artist working on milling 3D panels produced from pixelated images.

Image
Image

I have been using a script to generate an STL from the pixel values, and then I use PartWorks 3D to generate a toolpath and mill it on the ShopBot. This workflow results in really long milling times and me doing a lot of sanding because the surface finish isn't the best. The forms are very blocky (intentionally!)...I think it would be much faster and nicer looking if I could somehow do this in PartWorks 2D as a pocket toolpath, but this is overwhelming to do manually in PartWorks 2D. Does anyone have any ideas of how I could do this efficiently?

Thank you much!

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Adrian
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Re: Generate pocket toolpath from heightmap

Post by Adrian »

The tricky bit is creating the actual vectors. Once you've got those it's fairly straightforward and repeatable for fast toolpathing. Assuming each cut is the width of the tool, you would need to draw a broken line for each with the breaks coming at the height change.

Put each set of vectors for each height onto a layer. Create a toolpath associated with that layer that has a cut depth and start height which lines up with the overall vertical positioning in the piece. Repeat for each height. The toolpaths can be saved as a template and the re-loaded for any future jobs.

For future reference PartWorks2D is the same program as VCarve rather than Cut2D.

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scottp55
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Re: Generate pocket toolpath from heightmap

Post by scottp55 »

Surface finish can be improved a LOT with various options/bits. Maybe post another thread with pics/ bits/wood used (as well as your settings)?
Bound to be some excellent suggestions for you :)
scott
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oaktree
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Re: Generate pocket toolpath from heightmap

Post by oaktree »

Thanks so much for the quick replies!

Generating a vector image from the png is no problem...it's just a lot of shapes to deal with in PartWorks, and each one of these pieces I make starts with a different image. I will try what Adrian suggests today. I'm sure to have some follow-up questions.

Choosing materials/tools is a whole other problem, and I'll post specifically about that elsewhere too. So far, I use a flat end mill with the most cutting depth I can find...1/4" usually though 1/8" would be better if I could find longer ones and not break them. :) I also have been using wood, which is a terrible choice, and I'm investigating some prototyping materials now.

Thanks!

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scottp55
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Re: Generate pocket toolpath from heightmap

Post by scottp55 »

What is deepest point in the toolpaths?
I've learned my lesson well. You can't please everyone,so you have to please yourself
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ChrisInEstes
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Re: Generate pocket toolpath from heightmap

Post by ChrisInEstes »

oaktree wrote:
I have been using a script to generate an STL from the pixel values...
I'm interested in this "script" you're using to convert the pixel image to .stl. Could you share some more about that?

Thanks,
Chris
Aspire 9.5 - FlexiEXPERT 11 - Vytek Rebel 4' x 8' - 5HP Perske Spindle

oaktree
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Re: Generate pocket toolpath from heightmap

Post by oaktree »

Because it's an artwork and not a precision part, I adjust the height of my model to the tools I have available. The last one I tried was:

Freud 04-108 Double Flute Straight Router Bit 1/4" SH 1/4"D 1"CL

The one I used in the pictures I posted was shorter...I can't remember what it was. The taller I can make these, the more interesting I think they would be...

I was thinking more about the toolpathing...the roughing toolpathing is almost what I want to happen except it doesn't quite mill to the edges of my model...if that makes sense. The ridges on the vertical surfaces caused by the finishing pass are the problem (also the finishing pass takes forever and doesn't really help me all that much). During the roughing pass when the tool loops around the perimeter of each shape, the vertical surfaces look very good.

oaktree
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Re: Generate pocket toolpath from heightmap

Post by oaktree »

I'm using this to generate my .stl files: http://sourceforge.net/projects/heightmap2stl/. I use MeshLab to fix any problems in the model. Rhino and some other CAD programs can do this too though I haven't tried them for that.

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Adrian
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Re: Generate pocket toolpath from heightmap

Post by Adrian »

Not sure if it's practical or not now that I know a bit more about what you're doing but I've attached a file that uses the ideas I explained in my first post. It might give you some ideas.
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TheoryTest.crv
(268 KiB) Downloaded 138 times

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Mike-S
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Re: Generate pocket toolpath from heightmap

Post by Mike-S »

I'm not familiar with Cut2D's features, but can you do a Z-level rough with no allowance?
Attachments
pixelart2.jpg

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Adrian
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Re: Generate pocket toolpath from heightmap

Post by Adrian »

Mike, PartWorks3D = Cut3D and PartWorks = VCarve.

The post is in the wrong section really as it's nothing to do with Cut2D.

oaktree
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Re: Generate pocket toolpath from heightmap

Post by oaktree »

Sorry for posting to the wrong section...I didn't realize PartWorks was the same as VCarve!

Mike-S's idea is a good one, I will play with that too! Thanks for all the suggestions!

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