I have a Chinese galvo fiber laser with a JPT YDFLP-E2-100-M7-M-R laser.
Hi David, welcome to the forum!
My initial guess is that the lens is not parallel to the work area, and therefore the laser spot goes out of focus in the upper area
Does the outcome change at all in the front compared to the back?
I’d be interested in seeing four circles in each corner engraved at the same focal height.
You could also try tilting the metal plate forward slightly by placing something thin underneath it to see if that makes a difference.
How is the galvo head mounted on the Z axis? There might be set screws for adjustment.
Thanks for the tests and pictures.
I can’t really tell the difference between the front and back circles the way I was hoping.
These “glitches” here are kind of strange.
The brass plate looks very shiny. I’ve also had some strange results with pre-polished sheet metal, depending on the shine and reflection.
Can you try doing some tests with black paper?
That might give a clearer picture.
This first picture tells a different story. At least in the image, that looks very askew.
If you use the red dot assist lasers for focussing, I’d recommend doing a “focus test by eye and ear”, as instructed in the video on this docs page:
Then check whether the two red dots actually converge at this focal height.
I’m curious to hear the results!
Here’s a video with adequate filtering so you can see what I see with my eyes. Where the beam turns purple I presume that’s infrared as its not visible to my naked eye. https://photos.app.goo.gl/wZ2iLEW7jEXYUTBn7
I forgot to add that I did verify that red dots and the auto focus are all correctly calibrated.
No I didn’t, not well at least.
Did refocussing improve the result?
I still believe, that the lens and bed aren’t perfectly parallel.
This test with the black cards shows a gradual decrease in engraving strength from the bottom left to top right.
While the inconsistent engraving on the individual brass coin looks like a timing mismatch.
Which “Delay Defaults” are you using in the Device Settings?
If they are all at 100 μs, those are the defaults if your config file didn’t hold any timing information.
Delay defaults are all 100.
Did you import the manufacturer’s config file, when adding the laser, as instructed on this docs page?
That would be either a markcfg7, or markcfg0 file located in the a subfolder of the EZCad2 software.
If you did import it, that would mean it didn’t hold any timing settings, so LightBurn defaults to 100μs.
I’d suggest tuning the timing settings. This post will be of help:
I did import the markcfg7 file when I setup this machine. I opened it in notepad and anything with timing is indeed 0.
Oh nice!
Yes, definitely try those timing values.
Best to duplicate the existing device and name them apropriately.
Was this the first time you opened EZ2?
It’s possible, that the config file in the config subfolder only gets populated with those settings after the initial run. (I’ve seen that happen)
If you could perform an engraving test in EZ2, that would be interesting to see. (You would need to restore the driver. See here for instructions)
Your frequency of 30kHz is completely wrong for your laser source, its well below the cut-off frequency . The laser is running in protection mode (reduced power) to stop it damaging itself.
For your laser, do not go below the cut-off frequency of 75kHz/200ns unless you have a good reason too.
