Hello everyone! This is my first post here. I am operating a 1000*1000 leadscrew Ooznest Workbee. I am running it with Fusion360 CAD/CAM and it has a Duet 2 controller. Now I am running into 2 anomalies which might be related. I have searched the internet and I am still breaking my head over it so I hope you can help me. Thanks in advance. 1. Cylinder I am cutting a 26mm diameter straight cylinder out of pine wood with a 22mm depth. Using Fusion 360 CAM: 2D pocket, 2D contour, Circular On the top of the material it is exactly a 26mm circle. On the bottom of the material it ends up as a perfect 25mm circle (but 26mm intended!). When feeling the cilinder with the finger towards the bottom of the stock, some bumps can be felt which explain the shrink in diameter as the milling goes deeper. Checked already: -G-code at Z0 (bottom of stock material): X612,325 - X592,675 + 6,35(tool) = 26mm -Within the Y function in the Gcode there is not as much variation: between Y222.500 and Y223.135 (clue?) -Stock material movement: screwed it onto the spoiler board so excluded. -Tool: Just new: 6,35mm(1/4'') Flat end. Measured and in perfect condition. -There is a strange sound when it moves to XYZ home: it sounds like metal on metal friction. Could it be related to backlash? I have recently tightened a loose nut already, should I check this again? 2. Spoiler board levelling During the levelling of the MDF spoiler board (cutting away a few mm from the top) I encountered strange diagonal humps that occur when the machine starts moving from the left to the right. I have made some photos to make it more clear. The 'bumpline' can be felt from the middle of the board, going down diagonally to the bottom left as shown in the second picture.
Looks like you need to check the tramming Tramming is making sure the endmill is 100% perpendicular to the imaginary XY plane. The XY plane also has to be square and perfectly flat. See cnc tramming - YouTube
Thank you Peter. I am looking into that. Also I will check if there is any Z axis backlash as suggested in another forum. Let's say my machine is not perpendicular: would it lead to any of the symptoms I am diagnosing, and if: how?
It would explain the scalloping pattern on the bottom of your cuts. The hole with the sloping sides is less likely mechanical, and more related to cutting recipe: Do a roughing pass, then a finishing pass to clean up the remaining stock - that should get it to be same size. But before we go there, you want to be sure its true, perpendicular and spoilboard properly surfaced. Accuracy first, then we troubleshoot anything that remains
