Distorted engraving issue

Hi guys,

Have recently started getting this weird issue on some jobs.

It’s like the laser forgets or delays where it should be engraving.

Does anyone know what this is?

Speed is set to 500 with a dpi of 234 and is capable of much more.

You did not indicate where it failed to engrave. We cannot tell what should have appeared based on the writing style. I do see some light areas lightly burned due to wood grain, like in the “e” of Odette in the second image.

1 Like

Apologies, here we go:


If I was a CO2 owner, I might have spotted that right away. I have seen this before in postings, but you need a member with a similar machine to suggest fixes. The person I see most for CO2 issues is @jkwilborn. If he is not the best one, he knows who is.

I don’t think this is the case here. If this was occurring, we’d see a duplicate width burn equal to the text width … we don’t.

This looks much like we’ve seen before with an lps issue. It isn’t exactly the same, but it appears much more like this in the 2nd photo.

In this link, you can see a hardware failure that @ednisley caught on his scope. It clearly shows it lasing when the input controls to the lps have disabled the laser… Clearly a bad lps.

How does this fit your scenario?

Assuming a dc excited co2 machine…

If you look at your lps, it will give you some kind of response specifications… All of the ones I’ve seen are 90% rated voltage at <=1mS. You’d have to know how fast yours is to compute how fast it can toggle on and off.

If you want to stay within the actual limits of the machine and use the 1mS as a response time then …

With a 1mS response time, the best resolution you have at 1000mm/s is 25.4 dpi. At this speed, you can only toggle it off or on over a distance of 1mm…

500mm/s you can double the resolution to 50.8 dpi - at 250mm/s it’s again doubled to 101.6 dpi

This is beside the fact that with a 0.20mm laser kerf, you’re back to 128 dpi as a maximum anyway…


I think it’s something to do with setup/lightbulb/ruida

Basically when I hid send and send via USB on occasion when it faults it’ll transfer the file really quickly.

I then have to cancel it and start the job again which will take a little longer to transmit but will be correct.

Use Ethernet, it’s much more stable.


I think it’s more likely a USB problem than a power supply problem, because the errant burns happen far outside the area where the head should be traveling.

The normal behavior would be a scan back and forth over the name with a more-or-less rectangular overscan region extending a few inches beyond the name on each side. Those errant dots seem far beyond the normal overscan.

When those dots happen, does the laser head make a sudden jog far off to the side, then resume normal scanning? If so, then it’s almost certainly a communications dropout.

Although Ruida controllers can use USB, it was never intended for industrial control (which is what lasers really are) and produces so much trouble it’s always worthwhile to use the controller’s Ethernet connection:

And, obviously, practice on cardboard until you pin down what’s going wrong!