Vcarve inlay not fully clearing the pocket

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Bostaevski
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Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

Hi all,

I have two issues:

Issue #1
I am doing vcarve inlays on a Shapeoko 3 XL and when I carve the pocket, I end up with these nubs (see pics). This happens frequently.

I use the following clearance tools in order:
generic 1/4" endmill (the one that comes with a shapeoko 3), followed by
amana 46009-K upcut spiral 1/16"

Then the vbit
amana 45771-K 30 deg

In the Nub pics you can see that it's only maybe the last pass or so where these clearance bits assume the other did (or will do) the work.

Issue #2
Looking at the uneven bottom pic, this is clearly not what I expect but I don't know what causes this? It's not smooth and not all at the same level. This is from a 1/4" endmill. Am I running the feed too fast at 80 ipm? Is 40% stepover too much?
Attachments
Nub2.jpg
Nub1.jpg
Settings.png
uneven bottom.jpg

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adze_cnc
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Re: Vcarve inlay not fully clearing the pocket

Post by adze_cnc »

To be clear, the Amana 30 degree cutter is not a v-bit but an engraaing bit and should be enterered into the database as such.

Also remember that solid wood has tensions that release and causes exposed cut areas to expand and contract.

Bostaevski
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Re: Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

adze_cnc wrote:
Thu May 13, 2021 6:00 pm
To be clear, the Amana 30 degree cutter is not a v-bit but an engraaing bit and should be enterered into the database as such.

Also remember that solid wood has tensions that release and causes exposed cut areas to expand and contract.
I just downloaded the amana tools database so it is entered into vcarve as whatever that database file has in it. I attached a screenshot of the settings - but either way it should work fine for v-carving, no?

For the other issue I wouldn't think it would expand/contract perfectly along the cut lines, especially in endgrain. I'm guessing I need to slow down the feed rate.
30 degree tool.png

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Adrian
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Re: Vcarve inlay not fully clearing the pocket

Post by Adrian »

Have you trammed your spindle/router to make sure it's aligned 90 degrees with the spoil board? If not you will always get ridges in the bottom of a pocket/v-carve.

Also not all endmills are designed to cut cleanly on the bottom. Some only cut cleanly on the sides.

Bostaevski
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Re: Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

Adrian wrote:
Thu May 13, 2021 7:01 pm
Have you trammed your spindle/router to make sure it's aligned 90 degrees with the spoil board? If not you will always get ridges in the bottom of a pocket/v-carve.

Also not all endmills are designed to cut cleanly on the bottom. Some only cut cleanly on the sides.
I have not trammed the router - I will look into how to do that. Do you have any ideas on the first issue? It's clearly missing a small section where none of the calculated toolpaths touch that area, even though one of the clearance bits should have. To be clear I'm talking about the circled artifacts in the bottom of the pocket. When they appear on a carving they are always this shape.
InkedNub4_LI.jpg
InkedNub 3_LI.jpg

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Adrian
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Re: Vcarve inlay not fully clearing the pocket

Post by Adrian »

It's best to attach the CRV file so we can see the exact settings and how the vectors etc are defined.

Bostaevski
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Re: Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

Adrian wrote:
Thu May 13, 2021 8:54 pm
It's best to attach the CRV file so we can see the exact settings and how the vectors etc are defined.
Good point - should have thought of that from the beginning. I had to zip it so it was small enough to attach. I also deleted everything except this specific toolpath because otherwise it was still too large.
Joe Test.zip
(1.43 MiB) Downloaded 14 times

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Re: Vcarve inlay not fully clearing the pocket

Post by gkas »

Bostaevski wrote:
Thu May 13, 2021 9:16 pm
Adrian wrote:
Thu May 13, 2021 8:54 pm
It's best to attach the CRV file so we can see the exact settings and how the vectors etc are defined.
Good point - should have thought of that from the beginning. I had to zip it so it was small enough to attach. I also deleted everything except this specific toolpath because otherwise it was still too large.

Joe Test.zip
You can always upload to Dropbox or Google Drive.

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Adrian
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Re: Vcarve inlay not fully clearing the pocket

Post by Adrian »

If you run the toolpaths individually in the preview you can see where the machine is going wrong. Each toolpath should be clearing out the steps of the previous one as shown in the previews. In your actual cuts it's not which means you're either losing steps (pushing the machine too hard, binding on an axis) or the bit/machine is deflecting.

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Re: Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

Adrian wrote:
Fri May 14, 2021 8:53 am
If you run the toolpaths individually in the preview you can see where the machine is going wrong. Each toolpath should be clearing out the steps of the previous one as shown in the previews. In your actual cuts it's not which means you're either losing steps (pushing the machine too hard, binding on an axis) or the bit/machine is deflecting.
Thank you,

Yes I think this makes sense for the uneven bottom and I will slow down the clearance toolpaths next time... the 1/4" I run at 80 ipm and 16000 rpm.
But I don't think it would explain those nubs from the first issue... they appear frequently but only where vectors converge, and it only ever seems to happen on the final pass(?) In this project I have two different images of a deer (not the same image) and both of them have that nub thing in one of their hind legs where the vectors are converging and that 1/4" bit can no longer fit, so the 1/16" bit needs to do the clearance. Like you said, those nubs don't appear in the preview. Also I would think if my belt slipped a tooth, for example, the rest of the carve would be messed up but everything else is the correct dimension for the plug to fit seamlessly.

I don't know if it matters but I'm using the Shapeoko (mm) postprocessor.

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Re: Vcarve inlay not fully clearing the pocket

Post by Rcnewcomb »

The nubs would appear like that if the Z on the 1/16" end mill was set slightly too high or if the bit slipped upward into the collet.
Screen Shot 2021-05-14 at 3.41.18 PM.png
Personally, I'd just use the 1/4" end mill and the engraving bit. The bit change for the 1/16" end mill adds an additional opportunity for error.

You can probably increase your plunge rate and feed rate on the engraving bit since it isn't removing much material.
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Bostaevski
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Re: Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

Rcnewcomb wrote:
Fri May 14, 2021 11:46 pm
The nubs would appear like that if the Z on the 1/16" end mill was set slightly too high or if the bit slipped upward into the collet.
Screen Shot 2021-05-14 at 3.41.18 PM.png

Personally, I'd just use the 1/4" end mill and the engraving bit. The bit change for the 1/16" end mill adds an additional opportunity for error.

You can probably increase your plunge rate and feed rate on the engraving bit since it isn't removing much material.
If the bit slipped then the rest of the cut would be off I think?... I would swear if I didn't know better (and I don't) it's something wrong with how the toolpath is being processed in the postprocessor or how it is being interpreted by the shapeoko, for the fact that there's two of these nub things on this particular cut where the 1/16th bit just avoids that little area on its final pass , but otherwise everything else is cut perfectly. Anyway, yeah I agree probably should just skip the 1/16th and live with the extra time. I use the bitzero thing from shapeoko to re-zero my Z access between tool changes.

Well tomorrow I will tram the router thing and make sure the belts are all tight and maybe just stop using two different clearance tools.

Bostaevski
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Re: Vcarve inlay not fully clearing the pocket

Post by Bostaevski »

Rcnewcomb wrote:
Fri May 14, 2021 11:46 pm
The nubs would appear like that if the Z on the 1/16" end mill was set slightly too high or if the bit slipped upward into the collet.
Screen Shot 2021-05-14 at 3.41.18 PM.png

Personally, I'd just use the 1/4" end mill and the engraving bit. The bit change for the 1/16" end mill adds an additional opportunity for error.

You can probably increase your plunge rate and feed rate on the engraving bit since it isn't removing much material.
After rereading what you wrote I get what you mean by the bit being not at the correct Z. But in this picture you can hopefully see what I think I see, that the 1/16" bit is low enough to scallop out wood on the back side (red arrow) and it scribes a line around the orange circle, as if it assumes the other bit had cut that. The other nub thing on this cut looks exactly the same. So I assume the 1/16th is at the correct z level. Thanks for looking!
InkedInkedNub4_LI.jpg

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