Penn State Lion

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dvaskie127
Posts: 13
Joined: Fri Jan 13, 2017 10:14 am

Penn State Lion

Post by dvaskie127 »

Here is my latest project. It needs a little cleaning up but came out pretty good. The small lettering on the bottom came out a little rough. If there are any suggestions on how to make it better they would be greatly appreciated. Wondering if cutting them a little shallower would be better. I used a Vcarve bit 60 degree 1/2 inch 16000 rpm's and feed rate of 100 in/sec.
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PennState Lion.jpg

Rando
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Re: Penn State Lion

Post by Rando »

For the smaller lettering, a 30- or 45-degree bit might help you get cleaner, deep letters. And of course, the size of the very tip of the bit also determines the smallest feature size. When the letters look rough, it might also be a dull bit. Sharp bits cut better, but wood is a stringy stuff, so some little bit on the top of a v-carving is pretty normal to some extent. A light sanding is usually easier than a third, or fourth pass to clean up the last little bits.

One thing I'm curious about are the indentations at the inflection points along the longer curves, like at the top of the cat. This is usually the result of out-of-order vectors in a very small space. If you're using the Vectric software, you can use node-editing mode and then zoom way in, and you'll see paths like this:
StrangeVectors.jpg
That can be a pain to find and fix if there are a lot of them. OTOH, it could be an intentional part of the design :D.

Regards,

Thom
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

dvaskie127
Posts: 13
Joined: Fri Jan 13, 2017 10:14 am

Re: Penn State Lion

Post by dvaskie127 »

Rando wrote:For the smaller lettering, a 30- or 45-degree bit might help you get cleaner, deep letters. And of course, the size of the very tip of the bit also determines the smallest feature size. When the letters look rough, it might also be a dull bit. Sharp bits cut better, but wood is a stringy stuff, so some little bit on the top of a v-carving is pretty normal to some extent. A light sanding is usually easier than a third, or fourth pass to clean up the last little bits.

One thing I'm curious about are the indentations at the inflection points along the longer curves, like at the top of the cat. This is usually the result of out-of-order vectors in a very small space. If you're using the Vectric software, you can use node-editing mode and then zoom way in, and you'll see paths like this:
The attachment StrangeVectors.jpg is no longer available
That can be a pain to find and fix if there are a lot of them. OTOH, it could be an intentional part of the design :D.

Regards,

Thom
Thom,
Thanks for the advice. I attached the file with the tool paths and it looks like the bit is actually moving in a line towards the outside outline instead of cutting in a fluid motions. Would the node editing fix that?

Don
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PennState Lion.crv
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Rando
Posts: 757
Joined: Tue Jan 06, 2015 3:24 pm
Location: Boise, ID
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Re: Penn State Lion

Post by Rando »

Don:

Taking a look at the file, this one looks like a different thing, maybe good, maybe bad, depending on how you want it to all come out.

The ones you're seeing are VCarve's attempt to "dress" a sharp corner. By bringing the bit from the bottom upward along the apex of the angle, it can create a more accurate "faceted" bevels. It might look better with a smooth bevel, so I'll see if that changes things..yup. Got rid of those extraneous lifts.

What I did was use the "Fit curves to vectors" command (circular arcs, 0.01" tolerance, no sharp corners, yes replace), with the Keep Sharp corners turned off. Note that you don't have to do this will **all** the vectors, just the ones that are causing those corner gouges. I did this to the entire design, and it gently smoothed out the top of the head, and the toolpath doesn't show those corner lifts. The two images below show how that affected the toolpath. And yeah, I agree the simulator is a bit optimistic about quality ;-).
The original. Note the two dark lines heading "up" in the image (right side), trying to make a sharp corner.
The original. Note the two dark lines heading "up" in the image (right side), trying to make a sharp corner.
With all vectors smoothed. 0.01" tolerance keeps the curves close to the original drawing. Note the smoother curve and that the lion's top is smoothed, not faceted.
With all vectors smoothed. 0.01" tolerance keeps the curves close to the original drawing. Note the smoother curve and that the lion's top is smoothed, not faceted.
But again, you'd have to decide whether that changes your design in a good or bad way.

Regards,

Thom
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

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