Hi experts! After 10 years of dust I finally found room to setup my Ooznest OX. It has a 1000x750mm bed, a Spark xpro v2 controller board, and 4 NEMA23 steppers. The Y & X-axis are belt driven. I have trouble with finding the right setting for a smooth mill experience. See attached video's. I use 1/8 microstep for the steppers. The most important GBRL settings I use are: ----- Grbl 1.1h $0=10 (Step pulse time, microseconds) $1=25 (Step idle delay, milliseconds) $2=0 (Step pulse invert, mask) $3=7 (Step direction invert, mask) $4=0 (Invert step enable pin, boolean) $5=0 (Invert limit pins, boolean) $6=0 (Invert probe pin, boolean) $10=1 (Status report options, mask) $11=0.010 (Junction deviation, millimeters) $12=0.002 (Arc tolerance, millimeters) $13=0 (Report in inches, boolean) $20=0 (Soft limits enable, boolean) $21=1 (Hard limits enable, boolean) $22=0 (Homing cycle enable, boolean) $23=0 (Homing direction invert, mask) $100=107.256 (X-axis travel resolution, step/mm) $101=107.256 (Y-axis travel resolution, step/mm) $102=200.000 (Z-axis travel resolution, step/mm) ----- As can be seen in the vid (and esp. heard in the sound), every step is distinguishable, were you would expect a more smooth operation. It harms the final result, it makes the tool bite the wood. Are people here with similar challenges? Are these solvable? Any tips are much appreciated!
I don't think you're seeing individual steps - The feedrate *looks* very slow and it seems the tool is 'grabbing' at the work, then waiting for the machine to catch up, rather than cutting continuously. FWIW: I would try increasing the feedrate by at least 50% and see if it makes any difference. If nothing changes, go up by 50% again, etc. What feedrate are you using? (What 'feed per tooth' ?). It needs a *very* stiff machine to run low feedrates smoothly.
Could be runout on that "DC motor with a collet adapter pressed on" (those motors doesn't have sufficient bearings to be called a spindle)
Backlash somewhere, feedrate way too slow, depth of cut too much. On a belt drive OX you want to be using more of a 'high speed machining' approach, high feedrate with low depth of cut, high RPM. Sharp carbide tools. Try this, set the Z higher than the material so you can run the Gcode without it doing any cutting. Is that motion smooth?
Hi Misterg, David and Peter, Thanks a lot for reacting. I implemented both you solutions and right now I'm getting the results I expected! Couldn't believe switching from my 100$ spindle to Makita would make such a difference. Especially since no play was noticeable on the bearing. Right now I'm somewhere between 500-1000 m/min, with ~15000rpm and 5/6mm tool. This seems to work fine. Although I think I could even step it up after lowering micro stepping to 2 instead of 8. I turned it down since overheating of my spark xpro2 was causing x-axis to freewheel. Added a fan as well to solve this.
