Omitted material between roughing and finishing passes

Hi everyone,
I have a long-standing issue that I need some help with. See the red circles? Within the circle(s) is a section of omitted material (material that should have been removed on either the roughing or finishing passes). If the roughing pass didn’t remove it, the finishing pass should have, correct? Please let me know if you have a suggestion that I can try.
Easel, 1/4" downcut roughing, 60 degree bit finishing
Triquetra touch plate was used to set x,y, and z on both passes (though the problem persists when using other zeroing methods)

Capture


Is there any way that you can share the project?

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Brandon Parker

Published:

The toolpaths are correct.

I took a little closer look at your image and it looks like the areas of concern are not the only ones. All of the areas where only the roughing bit carved are higher than where the V-Bit carved. It looks like the Z-Zero was not set correctly for the V-Bit resulting in it carving deeper than the roughing bit.

Did you zero the roughing bit as well as the V-Bit?

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Brandon Parker

1 Like

Yes, I did, in all 3 axes.

The V bit is a 1/8" diameter and comes to a sharp point. Is it possible that the zeroing process failed to set the depth of the V bit correctly due to the point?

This would normally not be an issue with the default probing speeds. You are using the probe?

Is it possible that one of the bits became loose in the collet? Doubtful as this would have likely caused more varying depth issues.

Is it possible that after you ran the roughing pass and the large pocket was removed that you zeroed the V-Bit on a portion of the stock that had been removed? This would account for the V-Bit Z-Zero being lower into the stock material. My bet is that one…

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Brandon Parker

Also, do you have a 1/8" endmill? Using that as the roughing pass will reduce your overall cut time by just over 4 hours based on Easel’s approximation of the carve time.

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Brandon Parker

No, the portion of the material where the zeroing plate sat has not been cut by either tool. I was a machinist for several years, so I’m well versed in things like that. The odd part (to me) is that it seems to only be affecting the z axis.

I do have an 1/8" endmill, and yes, on the programmed feed rate, it will cut down on the time. I often run the machine harder than the value I put in for the feed rate, and the 1/4" tool is stronger, and will hold up to it better, so I opt for it occasionally. Will it make up for the time difference? Probably not.

Maybe something is loose on the Z-Axis? The belt or pulley maybe? Check pulley set screws if you have them on your pullies. The Z could have lost steps, but typically, I would expect the depth issue to be more erratic. The difference looks very uniform from the image…

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Brandon Parker

That’s a good point. I’ll check that when the machine is idle. Kinda weird that it would behave so consistently with something loose.

On a positive note, I found a workaround.


I would just check because it saves loads of time for the V-Bit since the 1/8" endmill can get to many more places than the 1/4" can. You would be surprised how hard you can push the 1/8" endmills in wood or softer material as long as your X-Carve is dialed in and as rigid as it can be.

Either way, that is up to you and how you want to operate your machine. Everybody has their own methods…

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Brandon Parker

Ignore the darker color on the roughing pass. The depths will be the same when I run it.

I figured as much…

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Brandon Parker


Looks good from the pictures thus far…

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Brandon Parker


That’s much better.

Marc,
Do you have nuts on the bottom of these bolts? The bolts should come in from the bottom. There is one picture in the install instructions that appears to show them being installed from the top, but they should be screwed in from the bottom unless you use nuts on the bottom so that the heads of the bolts can hold the bearing in place.
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Unless something changed, this is how the bottom should look…
image

I presume you pulled the lead-screw up and tightened the pulley. Did you tighten the nut on the top down as well? You should tighten that down as well since it is what sandwiches the pulley & bearing to the top of the lead screw.

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Brandon Parker