Odd Shaped Bore Holes

[ALSjosh]

Hi Everyone,

Newly converted Shapeoko 5 Pro to Acorn here! I am really just starting to get into the CNC12 software and things have been running great. I was machining a plate today and noticed some less than smooth movement of the machine on a bore operation. It almost looked a little "jerky" as the machine was boring a very small (2.5mm) hole. After the operation was complete and I looked at the hole, I could tell they were not nice and round. I am not sure how to describe this other than the hole just looks lumpy. I cant tell if its oblong in any certain axis or not. I have Oldham style ball screw couplers and the X and Y axis ball screws are 16/20 pitch. Everything seems mechanically sound and runs great but the holes are a big issue. Hopefully someone here can shed some light on what might be happening. In the picture, how I am holding the part is how is was oriented in the machine. Thank you!

[ShawnM]

There could be several reasons for this. Please post a current report from your machine so we can see how it's setup. The first two that come to mind are It could be a mechanical issue or your overall turns ratio is not setup correct. There are several more reasons but a report would help narrow it down. Also, start a Google photo album of your machine and share the link here so we can see what you are working with.

[ALSjosh]

Thank you Shawn. I was able to get back to the machine today and dialed in the overall turns ratio even tighter of a 12" travel on X and Y. 4" on Z. All of which were repeating within .0005". I checked all of the anti-backlash couplers (Oldham style Sewa couplers) and they were all tight. None of the ball crews and nuts had any amount of slop or play. I have been using this machine with the controller it came with for the past 9 months and have never seen this problem so I am wondering if I dont have some software parameter set correctly. Here is a fresh report from today and a link to my OneDrive folder with pictures and video. Could it be the Fusion Post processor?

https://aerologicsolutions-my.sharepoin ... A?e=EOlgWW

report_3484E42757CB-0506248229_2024-09-20_17-57-19.zip

(964.38 KiB) Downloaded 7 times

[cncsnw]

Could it be the Fusion Post processor?

Possibly. What do the circles look like, when you zoom in close using F8/Graph, F7/Zoom In?

Post a copy of the offending CNC program. The only CNC file in your above sharepoint folder appears to be something entirely different.

[ALSjosh]

Here is a picture from Fusion and I will get you a picture of the CNC12 display today. Also, here is the NC file for that particular project. The one I uploaded into the OneDrive folder was the one running in the pictures and videos in the folder. It seems to do this on all circular operations.

OP2_Top.nc

(417.17 KiB) Downloaded 9 times

[suntravel]

G-Code is ok.

I suppose the feedrate is too high for the stability of the machine.

Uwe

[ALSjosh]

Thats the strange part. I've been running these feedrates and higher with the stock controller and it was fine. Now that I've switched to Centroid I am getting these weird movements. I can run adaptive toolpaths at 120IPM with no problems and its smooth as butter.

[tblough]

The test is to run those holes at 10% of the feedrate you previously used. If the holes turn out round, then it is a machine issue.

[ALSjosh]

How could it be a machine issue if I have previously run this on a different controller with the same tooling and programs with zero issues? That makes no sense. This machine is not a new build, I have been running it since January and have never seen this issue until the controller swap.

[tblough]

Have you machined holes this size at the same feedrate with the same size cutter? Cutting 12" at 100" a minute, is quite a different thing than cuttind a 0.1" square at 100ipm.