Hopefully someone can help me figure out what’s going on.
I just upgraded to an SKR1.2 pro board with TMC2209 drivers. Everything seems to be working but I’ve been having some issues with some shifting in images when using a laser. See the pic below for an example:
First thing I checked was the grub screws on the X axis. Both motors were fine. I even loosened them and re-tightened them to make sure.
Next thing I did was loosen the belts. At first I thought they might be too loose but as I tightened them it started skipping more, so I loosened them a bunch. The problem is much better now but it still occurs. Not sure if the belts are too tight still but they already feel fairly loose in my opinion.
I decided next to search around and I saw someone suggest for someone else to run M122 to get some of their readings. I ran that and I’m seeing some strange numbers for the RMS. I’m wondering if this might be the problem I’m running into causing the shifting.
M122
X X2 Y Y2 Z
Address 0 0 0 0 0
Enabled true true true true true
Set current 900 900 900 900 900
RMS current 1602 1602 887 887 1602
MAX current 2259 2259 1251 1251 2259
Run current 28/31 28/31 28/31 28/31 28/31
Hold current 22/31 22/31 22/31 22/31 22/31
CS actual 31/31 30/31 20/31 22/31 31/31
The 1602 RMS on the X axis seems odd to me. Is that normal? It seems like most people when they post their M122 results have something similar to the 887 listed for the Y axis.
Any thoughts on this? Anything else I should check?
I had a similar problem with a laser engraver (not my Primo). I never understood the mechanical or electrical source of the problem, but my solution was to enable Scanning Offset Adjustment in Lightburn. This setting completely solved my issue, though it felt like I was masking an underlying cause.
I messed with it all day today and I just cannot figure this out. I loosened belts, tightened belts, checked the grub screws (again), lowered acceleration, etc. I also bumped the stepper current up to 1100 with no change. No matter what I do this keeps happening. Doesn’t seem to matter what speed I use either. Slower speeds still have the issue, it just seems to shift less. One oddity is that it only happens on fills. If I set light burn to line only everything works, no issue whatsoever. Here’s another one I ran a bit ago. You can see that it started going shift crazy at some point on the X axis, and throughout there’s numerous skips(?) on the Y axis.
I should also mention that I was previously running a ramps board until it died over Christmas. I used to run my primo in the series wiring mode and had no issues at all with a router. I picked up the laser over Christmas and upgraded the board to an SKR Pro 1.2 with TMC2209 drivers. Since putting the new board and drivers in I’ve had these issues. All the rest of the hardware is the same as what I had prior.
I just tried turning bidirectional off just to see if it changes anything and the shifts still occur. At this point I’m completely out of things to try. The only other thing I can think of is if the 2209’s I bought are crap. They were a cheaper no name brand that ran about $10 cheaper for a pack of 5. Unless anyone can think of anything else to try, I’m thinking I might order a set of the bigtreetech branded ones and see if that helps anything.
This picture is more enlightening. It does not look like something to be addressed by Scanning Offset Adjustments. It looks like lost steps. Have you changed the acceleration settings? What is your federate? Do you know if, at the end of the job, the laser returns to the same home/origin?
I know nothing about TMC2209 drivers, so hopefully someone else can give you feedback on your RMS settings.
I’ve run it at 15mm/s, and 30mm/s both with the problem. Slower speed still happens but the shift is less. Acceleration is at 125mm/s. Less than that and I’d run into burnt edges as the laser slows down unless I set a really large overscan.
The goofy readings on the rms are making me think these drivers are junk and have me hoping it is the problem.
As mentioned I never had any issues at all with the old ramps board using a4988 drivers but it bit the dust.
Just wanted to quick follow up on this. I think I have finally solved the image shifting issue, and it definitely appears to have been the stepper drivers. As soon as I replaced them the shifting quit occurring. Test images I’ve been doing actually look square now as well so something was definitely amiss with those cheap drivers.
in case anyone comes across this thread and has any other similar issues, these are the drivers that I bought originally and replaced:
I bought the official BigTreeTech ones to replace them and have had no issues so far. Long story short, DON’T BUY CHEAP DRIVERS!! Saving $10 was NOT worth it!
