I have a random dot problem. I came across this thread but there is no resolution! Dots appear all around engraving
Everything was going great and then my laser died. I wasn’t sure if it was the laser or the PS so I replaced both from light object. I bought a 45w SPT tube and a LO branded power supply. Everything else is exactly the same. I see it when engraving leather. For the most part you can’t see it in the final product after some oil or dye. But it is there and driving me nuts. It is outside the scan area too. Basically anywhere the laser head travels. No issue when cutting. Optics are aligned pretty darn good.
I did 3 test engraves. First one was 10% power which is where I like to engrave patches. Middle was 25% power. Bottom is 14% power. Air assist off for all engrave and on for the cut.
I would think that the dots would be worse on the higher power but they basically are absent.
Not sure how to attach an image that you can make bigger and zoom in. Hard to see it in the little picture.
Also, leather seems like it wouldn’t have too much of a problem with scatter or anything like that.
Not much showing up in your image. Are you sure you aren’t getting little pieces of burnt material flying off the engrave area?
If they were actual burnt spots, I would think oil would make them darker.
If you open the image on a new tab and expand it, they’re quite visible:
I would check the wires between the controller and the power supply to make sure the connections are secure and not too close to 120v wires or stepper wires, as both of those could induce electrical noise into the wires and cause the PSU to fire when it’s not supposed to.
Just thinking out loud here…
If it was electrical noise on the signal to the PS, why would that noise exist in a small window of power output? Once the power is sufficiently high the noise is almost completely gone.
Either way I’ll check that!
the oil darkens the leather around the burn marks bringing the difference in color down a little bit. They are still visible but the engraved/burnt areas don’t change much in color with the treatment I am doing.
The power output signal varies between 0 and 5v. If you’re running at 100% output, it’s 5v and going higher will not produce higher output.
If you’re engraving, the laser “trigger” is on, but the analog power setting is basically 0, so even a small noise spike in the line at that point can cause the power supply to fire.
That is very helpful information!
I will report back in a couple weeks when I have some time to dig in.
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