After recently discovering Meerk40t (v0.9.4), I’ve been really impressed with the features and possibilities it opens up for a K40 with an M2 board.
However, when raster engraving relatively small text over much of the build area, I’ve noticed the machine incrementally losing position and subsequent vector burns being significantly misaligned with the raster burns. This is not something that has occurred when using K40 whisperer.
My current thoughts about this relate to an audible clunk when the y axis moves between letters and I was speculating whether the y axis is losing steps with each of these clunks. I’ve retensioned the y axis belts and adjusted rastering speed but the clunk still occurs.
If anyone has any suggestions with regards to general improvements to the laser position consistency or more specifically about Meerk40t rastering and clunking noise on the y axis, that would be greatly appreciated.
I did have a play with that acceleration control setting and forcing it to the lowest setting, but it didn’t seem to make any difference. Thank you for the suggestion though.
In GRBL systems there are acceleration and speed settings for BOTH travels and for cutting/engraving. Sounds like you’re losing steps during the travel process so I would look to see if there’s a setting for that and try lowering the speed and acceleration.
I think it’s also traditional to note that loose grub screws on the belt pulleys (securing them to the shaft flats) can also be a source of clunks and misalignment. These show up most when an axis reverses direction.
As suggested, here are some images and a video showing my results and some of the settings used.
First of all, here is a link to the clunking sound on the Y-axis which I’m currently believing to be the primary issue.
The first image (in red) shows the result when using MeerK40t and the second image (in yellow) shows the result from K40 Whisperer. Since initially posting about my problems, the misalignment seems to be getting worse. Important to note is that the K40 Whisperer results also show signs of misalignment but to a much less significant level.
I think my next steps will involve completely removing the mechanical components from the laser and having a good look at everything. The laser was purchased second hand so I don’t know when it last had anything done to it.
Sounds like some sort of issue with the belt. But aside from that I have no idea what it might be. 250mm/s is a reasonable rastering speed - I can raster up to 450mm/s without losing position, so 250mm/s should be fine.
Remember that the Y axis on the K40 has the stepper motor mounted at the front of the machine and there are 2 drive gears(with grub screws) on left and right sides along with likely having a union to extend the motor shaft across the front of the machine.
When I listen to the video… it ‘sounds’ like a stepper motor missing a step… In My Opinion…
Eg; this is a specific sound that I associate with missing steps, which I have experienced mostly when pushing 3d printer extruders too fast. In my very subjective opinion this sounds like that, rather than a loose part.
So, I’d also suggest to check, with the power off, moving the Y axis by hand-turning the drive shafts. move it back and fourth in the region where you see problems. Does the shaft ‘bind’ at all? You should be able to ‘feel’ the stepper motor steps as a regular ‘roughness’ when rotating the shaft but that is all.
