Milling lines and Photo Edges

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scotta73
Posts: 3
Joined: Sat Apr 07, 2018 5:09 am
Model of CNC Machine: Xcarve

Milling lines and Photo Edges

Post by scotta73 »

I am getting started trying to make some lithophanes, and I'm running into a few issues. I was hoping someone might be able to point me in the right direction.

I have a few questions.
How do I get rid of the milling marks?
How do I get rid of the little round pockets around the image?
How do I get rid of the "fuzzies" in the corners?

For the attached example, I used candlestone. I measured the thickness with a set of calipers, and the material was .195" thick. I used Vcarve desktop to flatten it down to .15" thick, using a 1/4" endmill.
Then, in PhotoVCarve I used a 1/8" ballnose bit to make a roughing pass, and then a 1/16" tapered ballnose for the finish pass.

The final pass ran at .1 inch max depth, 10% stepover with a distance between lines at .006. My feed rate on the finish pass was 50 ipm, with a plunge rate of 20. The material is only a small piece 2 x 3 1/2", there were 677 lines to mill.

The image had the background removed in Photoshop, and the resulting area was cleared in PhotoVCarve using the "Make Color Transparent" feature.

I am milling on an X carve, with the DeWalt 611 router to power it.

I've been using Vcarve Desktop at home, and have gotten satisfactory results in other wood projects, but this seems to require a little more tweaking.
Any help you can give me would be appreciated. Thanks!
Attachments
Mill marks and border
Mill marks and border

NormanAlbert
Vectric Wizard
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Location: Dunnellon, Florida

Re: Milling lines and Photo Edges

Post by NormanAlbert »

The smaller the Lithophane, the smaller the bit used. I would have used a.040 or .020 diameter ball nose for the finish cut. And a 8 % step over. A feed rate of 30 imp is sufficient, the machine will rarely get that fast because of the z drive. Minimize Z clearance to a couple thousandths. For a piece that thin, You don't need the rough cut because at the diagonal direction of the cut the bit sees very little material per pass. Norm

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Xxray
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Re: Milling lines and Photo Edges

Post by Xxray »

No way to get rid of the lines once they are there.
If you use a 1/32 or at least 1/16 tapered ballnose with 8-12% line spacing, lines should not be visible.
If you in fact did that [hard to tell with variance of terms line spacing, stepover ect], then it boils down to you need to use a smaller bit to achieve greater resolution.

As stated, no need for a roughing pass.
Doug

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adze_cnc
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Re: Milling lines and Photo Edges

Post by adze_cnc »

scotta73 wrote:I used Vcarve desktop to flatten it down to .15" thick, using a 1/4" endmill.
I expect that what you're seeing are the ghostly remains of this pass. After you milled it to thickness did you do anything to remove those milling marks (e.g. "sanding")?

scotta73
Posts: 3
Joined: Sat Apr 07, 2018 5:09 am
Model of CNC Machine: Xcarve

Re: Milling lines and Photo Edges

Post by scotta73 »

Thanks for the info! I've not had a chance to run another litho as I'm out of material! Looks like I'll grab a smaller ballnose with my next Amazon order. I appreciate the feedback, and post back here when I get a chance to run some more!

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