I’ve written about this issue before but still haven’t found a solution. I bought a Redsail 150W laser and replaced the original controller (which used a parallel port) with an MKS DLC32. Since then, I’ve been having problems getting the laser to engrave the way I want. The setup uses external stepper drivers (Leadshine MD556).
After a lot of experimenting — adjusting motor current, changing microstepping, increasing logic voltage, and so on — it now seems that acceleration is the main issue.
With low acceleration, I get one kind of problem, and with high acceleration, another. Different feed rates cause different problems, but generally speaking, a high acceleration (20,000 mm²/sec) combined with a low feed rate (20 mm/sec) gives the best results — though that’s an unreasonably slow speed.
I would think that the MKS DLC32 should be able to handle this setup even with external stepper drivers. The drivers and motors are factory-installed — the only thing I replaced is the controller board.
Does anyone have any tips on how to get my laser working properly?
To me it looks like you have mechanical issues that are just more apparent at higher speeds. Also, what is your min power? , what is the thickness of your material? Has the machine been able to run at the desired speeds before?
What does a test (engraving) look like at high speeds with your machine?
I might be one step closer to a solution, but I don’t understand why. If I double the laser power, the results improve significantly. You can often compensate by running at high speed and higher power, but many times I need to engrave at lower power — and that’s when the problem becomes worse.
What seems to work is either very low speed with low power, or relatively high speed with high power — but not high speed with low power.
However, there are still issues with some lines becoming slightly wavy at higher speeds.
I’m starting to understand the problem now, although I haven’t solved it yet. When I drastically increased the laser power, the results improved significantly. It seems that my relatively powerful laser performs best at somewhat higher power levels.
To compensate for this, I increased the feed rate and started experimenting with acceleration in both the X and Y axes. I’ve found a decent “sweet spot” at a certain speed. However, I still get slightly wobbly lines at times, which may be caused by some form of oscillation or vibration during rapid direction changes. At lower speeds, this issue goes away—but then there’s a greater risk that the laser doesn’t stay on continuously instead.
