RASTER/Dither issues

Ok, recently purchased a cohesion3d laserboard. I have expanded the bed size and such and had everything running perfectly with the mk2nano. I made sure it was perfect as I know the cohesion is a drop in replacement pretty much.

Swapped in the cohesion board and everything works well. Tweaked the voltages up and bed size. All good.

Clustering enabled in lightburn. Latest version.

I can engrave a solid box set to fill at any size, for example 300x300mm at 400mms and it’s very happy. Same with vectors, any speed/file is fine and doesn’t have a single a problem.

But as soon as I try and do any image I have issues, let’s say a 300x300mm image. 240dpi and 400mms. X axis stutters gets stuck, stops and farts about. 300mms, same 200mms same, 100mms works but I can still hear the head micro stuttering. As if it’s stopping.

This is not a hardware issue as I can place a square box exactly round the image set to fill, click laser at 400mms and it runs like butter. With smooth sound at any speed.

Windows 10, tried 4 diff cables and used 2 different laptops.

It’s as if anything over 80 to 100mms causes the board to get stuck an not process it.

Yet again, I can swap the m2nano back in and 500mms raster is like butter. Machine is all linear rails and well aligned. Machine runs very fast and smooth.

Reloaded config file back to stock to test and exactly the same. If 80mms is my limit something’s got to be wrong.

Hi Adam,

Welcome to the forum!

Higher DPI means more GCode commands to process, and the board limits (with Clustering enabled) at about 2400 instructions a second, or 800 without. 254 - 300 DPI would be at the higher end of that based on our tests, so you’re below the range. Some image modes take longer. ‘Newsprint’ dither mode helps, as it clusters the shading in a way that reduces the amount of code sent to the machine. From what you’re saying, it sounds like you’re maxing at the old firmware rates.

In the LightBurn console, type version and hit return. Copy and paste the output here, please.

You might find this topic useful. It’s a different board, but the concepts talked about throughout refer to Smoothie and clustering limitations: Laser Head Stutters

I want to look at your config file to see if there is anything else we could potentially dial in. Please provide a copy of your configuration file for review. Copy and paste the content of the file in a reply with 3 backticks (on the tilde key in the upper left corner of the keyboard) ``` above and below the content. Example:

Paste content here

Alternatively, you can paste the contents to Dropbox, Google Drive, or Pastebin and provide the link here.