I have an 80w CO2 laser. Yes, I clean the lens and mirror after every use.
The issue is scoring in a project results in wavy lines, every time.
I have been fighting this problem for quite a while now and have done all sorts of troubleshooting.
Scoring is where the issue comes up. Engraving and cutting don’t have this issue.
It doesn’t matter what the project is, scoring always does this.
It looks like it will go away at certain speeds right? Well no. In this test it did, however, when I use the very same speeds that are ok in the test for a project, the issue still crops up consistently.
Very low speed and power help get rid of the wavy lines, around 25 speed, 11 power. With my laser, I can’t go much lower than that.
However, at that speed then the score lines and cut lines do not match up. In this photo, I marked that with red.
You’re seeing the flexibility of a large gantry accelerating after direction changes. The wobbles occur after corners where the Y axis changes direction, so they’re most obvious on straight lines running generally parallel to the X axis.
Reducing the controller’s Y axis acceleration will reduce, but not eliminate, the wobbles.
On a Ruida, that value is in Edit → Machine Settings → Vendor Settings → Y Axis Settings → Maximum Acceleration:
Because the controller modulates the power based on the speed, you may find a lower acceleration requires a lower Min power level for more headroom.
The controller has several other acceleration limits that may also affect the outcome. I think:
Cut Parameters apply to motions with the laser on
Idle Parameters apply to motions with the laser off
Engraving Parameters apply only to back-and-forth engraved areas (duh)
Documentation on those parameters is basically nonexistent, so careful experimentation is the only way to fly. I think the Cut acceleration caps the X and Y values, but I haven’t done any careful measurements.
Well, I did a bunch of testing and those settings didn’t work.
It still seems that the only thing that gets rid of the wavy lines is to slow down to like a 25 speed. But then, the cut lines and scores lines do not line up at that speed.
As I wrote earlier, the gantry / Y axis acceleration matters more than the speed, so you might have more success (or at least different success) by varying the acceleration at normal speeds.
This test pattern may be help pin down the changes:
Scale it to fit the platform and run it as fast as it will go in Line mode with optimizations turned off and power set to mark a sheet of cardboard.
If the acceleration is now 3000 mm/s², cut it down to 100 mm/s² and it’ll take forever to get up to speed, but will likely track perfectly. Increase the acceleration by factors of two until the problems creep back in; if you can live with a lower acceleration, that’s the solution.
Also, make sure the Ruida controller has the proper Step signal polarity (a.k.a. PWM Rising Edge Valid), as described in this discussion:
The symptoms don’t exactly match what you’ve shown, but it’s worth verifying.
