Lithophane Tutorial Revisited

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kristenanne77
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Lithophane Tutorial Revisited

Post by kristenanne77 »

I keep going back to the lithophane tutorial (Cute Puppies)
http://www.vectric.org/video/photovcarv ... arted.html

And just when I think I "get it", a week later I have another question.

In the tutorial it shows doing a roughing out with a Carving Max depth .1 inch and then a follow up fine pass with a smaller bit with a Carving Max depth .1 inch.
I am assuming that the roughing pass cuts out the bulk making way for the smaller bit in the finishing pass., and that the Z zero point of the finishing pass is the same as the zero point of the roughing pass.
If this is true then the depth from both roughing and finishing passes is .1 inch. (and .15 inch left uncut to equal a total distance of .25 inch.

Then the tutorial mentions that if the material is only .125 inches, and the Carving maximum depth maximum depth remains at .1 inch, that only a finishing pass is all that is necessary.
If the Carving Max depth is the same at .1 inch, why isn't a roughing pass needed?

Although the thickness of both materials are different, the total amount cut (Max Carving Distance) for both is .1 inch ... So why is a roughing cut needed in one example and not in the other?

Thanks
K




So the depth

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Mike-S
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Re: Lithophane Tutorial Revisited

Post by Mike-S »

Graphic1.jpg
I can't answer the specific question, but the roughing pass is normally used to get rid of excess material that the finish bit would struggle with. For lithos I don't use a roughing pass since the finish bit is only taking 8 per cent or so of a bite. The only place that's not true is on the first pass where it would obviously take 100 percent. So two ways to not strain the bit: 1) Cut a boarder around the litho first, down to about 90 percent of the max cut depth, or 2) Start the litho in a corner and cut out with 45 degree angle passes. So only the initial plunge cuts 100 percent of the bit diameter and all other passes are at 8 percent. I like the boarder method as I think it looks more classy.
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kristenanne77
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Re: Lithophane Tutorial Revisited

Post by kristenanne77 »

Sorry but I still don't understand.
Two Questions
1)
Isn't the goal to cut the corian almost all the way through?
If using a .1 inch total delta of bit movement from the surface, then 0 inch would be the surface (the darkest areas when light shining through the back) and .1 inch depth being the deepest cut area (the lightest area when light shining through the back).... this still leaves .15 inch of corian under the deepest cut of .1 inch. and .25 inch of material at the darkest are where nothing is being cut. Isn't this .15 inch to .25 thickness under the lithophane too much material for light to shine through?

2)
How do you cut the border in Photovcarve. I don't think I saw an option for this.

Thanks
K

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Re: Lithophane Tutorial Revisited

Post by Bob Reda »

go back and look at the pdf file. In the video they forgot to mention one very important step.

Bob

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Re: Lithophane Tutorial Revisited

Post by kristenanne77 »

I looked at the pdf file. Let me know if I passed the test!
From what I gathered , for a piece of material .25 inches thick. the roughing toolpath's "zero point" starts at at -0.08 inch.
Then if its maximum cutting distance is .1 inch (below the .08 inch), then it so will end up cutting from -.08 inch to - .18 inch.
Then the finishing toolpath's zero point is at -0.1 inch (which is a deeper starting point than the roughing toolpath) and will cut down to -0.2 inch, leaving .05 inch material left on bottom.


Question:
This makes more sense, except I do not understand why the finishing pass starts at -0.1 instead of -0.08 (the same as the roughing cut).

Thanks
K

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dhellew2
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Re: Lithophane Tutorial Revisited

Post by dhellew2 »

Lithophanes are all about what's left not what you cut away.
I posted a downloadable pdf for Aspire and V-carve that gives a lot of information about setup and cutting Lithophanes that may be of some help.
Dale
http://forum.vectric.com/viewtopic.php? ... ns#p169220

or just search for lithophane instructions
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kristenanne77
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Re: Lithophane Tutorial Revisited

Post by kristenanne77 »

Thanks, but unfortunately your instructions deviate greatly from what I can do in Photovcarve.
I also have VCarve desktop , which has some of the 3D modeling functions, but unfortunately cannot do lithohanes.

It would be great if someone had instructions as detailed as yours but for Photovcarve.

Thanks
K

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Re: Lithophane Tutorial Revisited

Post by calgrdnr »

Here is tutorial on oval lithophane in PVC it has all the steps to make great lithophane in Photo V Carve

http://forum.vectric.com/viewtopic.php? ... hilit=oval any question fell free to ask :)

its 6 years old but do believe no changes to PVC ....


Kent

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Re: Lithophane Tutorial Revisited

Post by bill565 »

There are a couple of ways to skin the proverbial cat. (Poor Thing)

You could consider the different tooling approaches that could be utilized. I use a single tool single pass strategy with a 30Deg V-Bit configured like a very small ball nose.

I use a small step over and cut in a single pass with a diagonal cut to minimize the load for the first cut.

I only have to set z to my reference and then I can control the depth of cut where ever I want for the material. Works great for me and there are a lot of posts regarding this approach.

Good Luck

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kristenanne77
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Re: Lithophane Tutorial Revisited

Post by kristenanne77 »

bill565 wrote:There are a couple of ways to skin the proverbial cat. (Poor Thing)

You could consider the different tooling approaches that could be utilized. I use a single tool single pass strategy with a 30Deg V-Bit configured like a very small ball nose.

I use a small step over and cut in a single pass with a diagonal cut to minimize the load for the first cut.

I only have to set z to my reference and then I can control the depth of cut where ever I want for the material. Works great for me and there are a lot of posts regarding this approach.

Good Luck

Bill

How would you configure a 30 degree V bit as a ballnose?
(Although not entirely related, I also made a separate post with a question about ballnose bits)

Thanks
K

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Re: Lithophane Tutorial Revisited

Post by calgrdnr »

Just tell vectric software you are using 0.03 ball nose but use vbit instead :)

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