Circle pocket not ending up a circle

CNC Machines Shapeoko
1

Hey everyone,

I’ve got the Shapeoko 3 XL and whenever I attempt to pocket a small-ish hole (~1" diameter) using a large-ish endmill bit (0.25"), I get bad results (see image below). I have tried decreasing the plunge rate, feed rate, and depth/pass without improvement. The bit seems to just hover in place when it should be moving to create the proper profile. I am able to make larger curves with no problem. Is this just an issue of trying to do too small of a pocket with too large of a bit or are there other settings I should be tweaking to improve the functionality?

Thanks!

Caleb

IMG_3173.JPG1224×1632 992 KB

2

What happens when you make a square?

3

Backlash like this is usually a pulley set screw — http://docs.carbide3d.com/article/169-shapeoko-3-how-to-check-the-pulley-set-screws

Another possibility is a motor which isn’t working — slacken the belts on the Y-axis and make certain that both motors turn.

Also check belt tension, and that it’s even on both Y-axis belts.

Which CAM tool are you using? Can you control the orientation? Force it to start in the center and work its way out? Leave a roughing clearance and then make a finishing pass?

4

Thanks Will, I will check the set screws. I am just using Carbide Motion for CAM so I don’t think I can control the starting point outside of creating two paths, but I’m fairly certain this path began centrally.

5

@SwapmeetPete

With the power on to the machine, are moth Y motors locked?

Check the tightness of bolts that hold the V-wheels. specifically on the X carriage.