Before you play with settings too much, make sure your rails are all clean and lubricated. If you’ve had the machine for a while and don’t clean it regularly, gunk can build up on the rails or in the bearings. Any binding in the motion system can mean the steppers have to work harder to do their jobs, and at some point they’ll slip.
If you’ve done that already, there are a few settings to play with that can help:
Idle speed is how fast the laser head moves between cuts. Idle acceleration is how fast it gets to that speed.
Min and Max acceleration control the acceleration during cutting. (I don’t have a good understanding of what Min acceleration does).
Stepper motors have poor torque at high speeds, but high torque at low speeds, which makes this a little more complicated.
If you reduce the maximum speed, but leave the acceleration, it will move short distances quickly, but long travel moves will take a little longer. If you reduce the acceleration, but leave the speed alone, it will take longer to get to full speed. Short moves will take a little longer, but long moves will still happen faster.
In my experience, lowering the acceleration usually does a better job of preventing slips overall, and reduces the amount of shake you get from the machine when doing jobs with lots of small rapid jumps. Try dropping idle acceleration by 25% and running a low power test. If that doesn’t work, drop the idle speed 25% too. If that doesn’t help, do it once more. My red/black machine from China shipped with very “optimistic” settings, so depending on where you got yours, it might need a bit of tuning.
If it’s a recent purchase from China, they sometimes (often) set the speeds a little optimistically. I know my own generic red/black was set way too high and slipped a fair bit until I dialed it down. Didn’t affect the job time much, but improved the reliability quite a bit, and got rid of a few little wobbles in the lines to boot.
It’s closer, certainly. You might just have a loose set screw or something mechanical. If the machine is new, it’s not uncommon for the little grub screws that hold the belt pinions on the steppers to loosen out a little. It doesn’t have to be much to cause slip.
Here is the engrave in the middle and then cut rectangles around the engraved rectangle
You can see it’s not a simple shift in alignment from the engrave to the cut it looks like it’s getting worse as the engrave continues(possible slipping but only when it engraves at higher resolution)
Also I slowed the machine down to as slow as 300 and it’s the same results as the original 3000mm
I checked backlash but that didn’t help and my line scan offset is perfect at 0.8 but the finer I get the more it skews
I’m lost and I’m sorry my technical terms/speak is that of a noob
Is this a new machine? If so, check everything mechanical first. Make sure everything is tight, including (especially) set screws holding the belt pinions in place. If those slip a little every time you change direction, it wreaks all kinds of havoc.
After checking everything mechanically, the next thing I would check is the motor pulse polarity:
Don’t assume it’s software or configuration until you’ve eliminated everything else. If the settings were actually correct when it arrived and you change a bunch of them, it’ll be hell to figure it out later.
