X-Y direction different sizes!
I have a nicely assembled Ratrig 3.1 400x400 printer. I made a calibration star with flat measuring tips, where the two diagonals and the vertical and horizontal dimensions should be 250mm. While I managed to adjust the diagonals nicely with belt tension and rotation distance fine-tuning to 250.00 mm, the horizontal and vertical dimensions (x-y) differ from this. It doesn't matter if the belts are stretched like guitar strings or hanging like pants strings, the vertical dimension is larger: 250.25mm and the horizontal dimension is smaller: 249.90. The difference decreases if the calibration print is smaller. My question is what kind of physical component movement (jerking, tension, inaccuracy, etc.) can cause the difference that a different size occurs when both motors step the same amount in one (X) or the other (Y) direction? (The machine components are visually fine, no software skew correction or other mischief has been set.) Please help, accuracy is important. X-Y 0.3mm difference is not allowed in my projects, I would not change the slicing of the 3d file to eliminate the hardware error just for this one machine, since I use the G-Codes on other machines and the X-Y-A-B dimensions are good there. Thank you for helping with your ideas and experience!
3 Replies
just use the skew adjustment
https://www.klipper3d.org/Skew_Correction.html
though I am fond of https://vector3d.shop/products/califlower-calibration
We are discussing this issue here and we suspect bad quality on pulleys. See thread here
https://discord.com/channels/582187371529764864/1324815117292011570
thank you I will follow it!!