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Skewed engrave

Posted: Tue Mar 02, 2021
by Gary Hillis
Hi,

My laser is pretty new and does not get used much. It cuts great but the engraving is skewed on all engrave tests I have run. Everything I engrave looks italicized. it engraves at the same angle every time. It seems to only affect the x-axis. Your help would be appreciated.

Thank you and stay safe.

Gary

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by sebastien laforet
the most probable cause is "lost steps".. on each line, the acceleration/speed is too much for the motor, so it moves less than expected by the controller.

you can decrease the speed, and/or check your acceleration values. the acceleration is pretty irrelevant for cutting, but when you set a high engraving speed, it counts a lot.

setting an acceleration too high is a recipe for failure. you can lose steps, and it will mechanically stress the machine (belt, pulleys, vibrations ...) for no real gain.

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by Gary Hillis
My engraving speed is 1.5" per second. So not really that fast. Would there be any other issue?

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by sebastien laforet
it seems incredibly slow, especially for a 150W machine. are you engraving stone or corian?

for co2 machines (not diode lasers), speed in the order of 200 or 300mm / s are usual for engraving. some can achieve 500 or more mm/s with correct tuning of backlash, reverse interval.

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by Gary Hillis
I have ran the engraver at 200 and the result is still the same. please advise.

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by sebastien laforet
well... are you really sure there is no skewing where cutting also? i might be less visible especially on small parts. cut a large square and see if it's really square as expected. if not, check the alignment of the gantry.

also, do you have a photo of the result?

you can try to engrave a plain square, large enough, with a large interval (like 2 or 3mm), so you could see each line and try to measure if the skewing is homogenous or not.

are you using bidirectionnal engraving? if so, have you tuned the reverse interval (see https://cartonus.com/how-to-improve-eng ... r-machine/ especially at step 4)

does the machine move laterally when engraving? does it vibrate? is the movement on the rails fluid or does it have friction points?

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by Gary Hillis
Thanks for the update. I will look into theses issues and get
back to you.

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by Pete Cyr
viewtopic.php?f=105&t=3528&hilit=100mm

Check out the link above as well

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by Frank Small
Gary

I ran into this on my machine while trying to engrave. It was like reversed italics.



Cutting was fine but engraving looked like this. I found it was caused by going to fast (like 400mm a second) and having bidirectional fill off. With bidirectional fill on I had what looked like double hit in the text (top right corner) still to fast.

I hope this helps.
792914F8-A2C6-4836-ADA2-9E2368BB08BE.jpeg

Re: Skewed engrave

Posted: Tue Mar 02, 2021
by Gary Hillis
Hi Frank,

That is pretty much the same issue I have only the skew is the opposite direction. I will look into your suggestion. Thank you