small waves in upper and lower corners when cut

[Martin Safranek]

Hi all,

now i have small issue with my weike LC1612. When i cut square i have small waves in upper right and lower left corner.
I will welcome any hints because i dont have any clue.

Thank you.

Martin

[Kev Williams]

First thought is always that the X belt may be too loose or too tight, but the wobble is actually a function of the Y axis... I have a feeling the accel/decel settings need adjusting, as the head is probably only barely slowing if at all before it changes direction. I'm betting it's cutting CCW and the wobble is the result of the whole gantry shaking briefly as the Y motion suddenly stops as the head turns 90°. I'm also guessing if you slow the speed down to about 1/3 of what you had it, the wobble will just about disappear ;)

[Dave Sheldrake]

Kev's on the money, it's butt wobble, like trying to drive a car round a 90 degree corner at 80mph, steppers don't like doing violent direction changes

[Michael Hunter]

Also check that the head/lens assembly is all done up firmly!

[Rich Harman]

...now i have small issue...

What speed were you using? It looks like you simply have the speed setting too high but you say "now" you have the issue - does that mean in the past you have cut at the same speed without those wiggles?

Your 1612 has a real long gantry, that's a lot of mass to stop instantly at a corner.

[Martin Safranek]

Thanks to all for Hints. Problem was solved by lowering acceleration parametr in lasercut. I had 40mm and now with 20 problem disappeared. It seems that some screw must loose tight because week ago was everything OK. I found this problem during cutting 1.6mm rowmark sheet with speed 40mm/s.

Thank you very much.

Martin