Slight X Axis variation

Assembly questions and answers for the Shapeoko 3 CNC Mill
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jlangemak
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Joined: Tue Feb 20, 2018 11:49 pm

Slight X Axis variation

Post by jlangemak » Sat Apr 07, 2018 1:43 am

Hi All! I ran into somewhat of a curiosity that Im looking for feedback on. I recently attempted to make a Go board and encountered what appears to be slight variation when cutting in a straight line in the X Axis You can see that in the picture below of the maple checkerboard cutout.

Image

Notice along the top you can see a slight waver in the edge line. Noticing this, I thought perhaps it was being caused by some dust or debris on the rail or in the v-Wheel. So today I took the whole carriage off and cleaned all of the vwheels with a tooth brush and ensured the rail looked fine. Put it back together and ran some test cuts. In the image below you can se the results.

Image

Whats interesting to me is that when I measure this - the imperfections in the line are ~70mm apart. When I measure a vWheels circumference, I come out at around 65mm. Is it possible that I have a deformed vWheel that's pushing the carriage out of square briefly? Any other ideas what could be causing this?

AnonymousPerson
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Re: Slight X Axis variation

Post by AnonymousPerson » Sat Apr 07, 2018 3:11 pm

It does sound like it could be something along those lines.

As a general thought... if the waviness is along the X axis, doesn't that mean it's probably the Y axis wheels not being 100% right?

Kind of thinking they'd be the ones most likely to cause something like this if one of them is a bit off. :)
Shapeoko 3 #516

jlangemak
Posts: 13
Joined: Tue Feb 20, 2018 11:49 pm

Re: Slight X Axis variation

Post by jlangemak » Sat Apr 07, 2018 7:35 pm

Yeah - likely a matter of terminology. Im thinking its the vWheels that are running on the rail that extends across the X axis. That is - the ones that are holding or supporting the Z Axis carriage. Thing is - there's 4 of them and Ive already taken them al off once to clean them. If it was an obvious issue with the vwheels I didnt see it on the first try.

So do I just look to replace them all and see if that helps?

jlangemak
Posts: 13
Joined: Tue Feb 20, 2018 11:49 pm

Re: Slight X Axis variation

Post by jlangemak » Sat Apr 07, 2018 9:17 pm

So I just took them all off again and inspected them. One of the wheels happened to have a bit of black plastic sticking to it - maybe from the manufacturing process. I removed it and put it all back together. Test cuts still show a slight variation every 70mm. The only thing I can think of is that one of the wheels is out of true but that seems like a stretch.

Any other ideas? Im sort of tearing my hair out. I've got a project I want to cut that has that long straight line and I'd like to sort this out before I cut it.

AnonymousPerson
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Re: Slight X Axis variation

Post by AnonymousPerson » Sat Apr 07, 2018 10:30 pm

Ahhh. Terminology wise, I was thinking of the other wheels. The two sets (left side and right side) that run from the front to the back of the machine, which the "Y" axis goes along.

Looking at the photo's I was thinking maybe there's something slightly off with one of them, which is causing it to move a fraction (either forwards or backwards) at some regular interval. Same as what you're thinking (I think) but we're thinking at 90 degree angles to each other.

Anyway... take a look at those wheels too (yep, all 8), just in case? :)
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WillAdams
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Re: Slight X Axis variation

Post by WillAdams » Sun Apr 08, 2018 2:02 pm

If it's a new machine, contact support@carbide3d.com

If you're out of warranty, my suggestion would be to make a small test stand, get a set of calipers pull all the wheels and then measure them in the test stand --- if you find that some are noticeably out of spec due to wear, then get https://shop.carbide3d.com/collections/ ... enance-kit
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

jlangemak
Posts: 13
Joined: Tue Feb 20, 2018 11:49 pm

Re: Slight X Axis variation

Post by jlangemak » Sun Apr 08, 2018 4:45 pm

Thanks - I reached out to support as well. I just realized that the variation moves between my test cuts (taking off the wheels and checking them) so that tells me it isnt the rail - Im almost dead set that its the vwheels at this point but I just need to narrow down which one it is.

LTEPM
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Re: Slight X Axis variation

Post by LTEPM » Mon Apr 09, 2018 2:09 am

I see your correlation and it appears repeatable. How much deflection are you experiencing?

Do you experience the same issue when doing a pocket cut? For example using a 1/4” bit for a 5/16” wide pocket with multiple passes?

Have you checked the belt idler pulley bearings on the back of the X axis plate to see if they are rubbing?

Have you checked your Z axis wheels to make sure they are tight all?

Are you doing conventional cut or climb cut?

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