Trouble with new laser

[closeracing]

Hello everyone, I purchased a machine from Unichcnc with a Ruida RD6442S control system + software for a monument business. The trouble I am having is that dark areas are not visible in the engraved image on granite. If I increase power enough to show darker areas, the light areas are way too bright, usually burnt. These are files that look great when engraved with other machines, I even sent the file to the manufacturer to run and it looked very good, so it's not the files. Here are a few of the things I've tried. Checked alignment, cleaned mirrors, cleaned the focal lens, replaced the focal lens, installed the latest version of RDworks, changed sweep and cut parameters to recommended settings from the factory. What would cause the laser to fire too weak or not at all in darker areas?

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[wmgeorge]

When I do granite the dark areas are not touched by the laser beam and the light or white/ grey areas are the ones hit by the beam, correct? So the detail in the shaded in between area depends on the dithering or spacing of those dots. It could be and just guessing the space between the dots, the beam goes off and then does not come on fast enough or at enough power. To prove, I would try slowing down the speed a little at a time until you get that detail Do some testing on some scape pieces or purchase some at Home Depot. . I have no idea of the power and speeds your running but it does not take a whole lot of power to do granite.... at least what I have seen anyway.

[closeracing]

When I do granite the dark areas are not touched by the laser beam and the light or white/ have tried greyI areas are the ones hit by the beam, correct? So the detail in the shaded in between area depends on the dithering or spacing of those dots. It could be and just guessing the space between the dots, the beam goes off and then does not come on fast enough or at enough power. To prove, I would try slowing down the speed a little at a time until you get that detail Do some testing on some scape pieces or purchase some at Home Depot. . I have no idea of the power and speeds your running but it does not take a whole lot of power to do granite.... at least what I have seen anyway.

I have tried speeds between 100 and 400 mm sec, power from 16 to 54% and everywhere in between. You are correct, I was referring to dark gray areas where the laser should be firing but is not. Last night I was on skype with the technician in China and they had me run a crappy file of a tiger at 100 mm sec. it was bright and didn't ruin the light areas, but the quality was pretty bad and the dark areas didn't show. Any idea what could cause this? Could it be a weak power supply or tube?
My laser is a 60w 1318 btw.
Thank you for your response

[wmgeorge]

If you had a weak tube or PS the tube would not have as much power, but since your able to do the white area without issue I do not think that's the problem. Not sure how your doing the mirror alignment but it has to be done in a certain sequence to make the end result correct.

I still think its a timing or on-off problem and that could be from the Controller or HV PS. Does the motion control work without issues no jerky movement or rough spots?

Try the same file on some smooth birch or pine, is it ok?

[closeracing]

If you had a weak tube or PS the tube would not have as much power, but since your able to do the white area without issue I do not think that's the problem. Not sure how your doing the mirror alignment but it has to be done in a certain sequence to make the end result correct.

I still think its a timing or on-off problem and that could be from the Controller or HV PS. Does the motion control work without issues no jerky movement or rough spots?

Try the same file on some smooth birch or pine, is it ok?

The files look pretty good when I reverse them and engrave wood.
It will even do a decent photonegative on granite that way. The only trouble I've had with the controller is with an extremely large file. It would go haywire and I'd get an error saying something like "not enough space" it did do that once today on a smaller file though. It made the image look like something out of a hall of mirrors at a carnival.

[wmgeorge]

The files look pretty good when I reverse them and engrave wood.
It will even do a decent photonegative on granite that way. The only trouble I've had with the controller is with an extremely large file. It would go haywire and I'd get an error saying something like "not enough space" it did do that once today on a smaller file though. It made the image look like something out of a hall of mirrors at a carnival.

How are you getting the file into the controller? Not by USB drive I hope they can corrupt files at times IF they go bad.. If so try just the direct USB cable download to controller. Same problem> your controller is bad.

[closeracing]

How are you getting the file into the controller? Not by USB drive I hope they can corrupt files at times IF they go bad.. If so try just the direct USB cable download to controller. Same problem> your controller is bad.

I load files directly from the computer via a cable. Is there a way to check the controller?
Thank you very much fir taking the time to help me out btw. This was a big investment and an even bigger disappointment

[wmgeorge]

I load files directly from the computer via a cable. Is there a way to check the controller?
Thank you very much fir taking the time to help me out btw. This was a big investment and an even bigger disappointment

I do not know of a way unless the seller or manufacturer have a method? While you still have access to the controller, take some screen shots or saves of the set up and parameters screens. When or if you replace the controller it has to have those same settings.

[closeracing]

Ok I spent all day yesterday perfectly aligning the mirrors and troubleshooting laser tube. The beam on mirror 3 was not dead center when at the closest point to mirror 2 (though very close). Now all 3 mirrors are dead center everywhere, of course, it made no difference.
The tech seems to think it's the tube, so I had to make a continuous video of Reci's troubleshooting procedure and send it off. The factory will get back with me Monday. I'm with you, I think it's a bad controller, but maybe they are right.
I noticed something strange today. While attempting to run a test file, the tube was firing fairly bright but there was no firing at the nozzle. I did a pulse test and it fired fine, still dead center. I restarted the laser and put a piece of cardboard between number 2 and 3 mirrors and nothing.
I should know more Monday, thanks for your help, I'll keep you posted

[abyss]

While attempting to run a test file, the tube was firing fairly bright but there was no firing at the nozzle. I did a pulse test and it fired fine, still dead center.

(All - if I good understand you). If tube is glowing pink "normally" when firing and you can't mark fair anything outside tube there are 2 options in my opinion: - you have not enough free oxygen atoms in your tube and nitrogen (which is glowing pink) can't "charge" oxygen (Reason: old or used tube, oxidation on internal tube electrodes, other damage inside the tube). If the laser is firing almost normally, but shape of the beam is unusual that can be mechanical problem with internal mirrors in the tube or mechanically over- stressed tube (way too tight clamp etc). Generally - bad prognosis.

[closeracing]

Hmmm. Thank you for your input. The machine is supposed to be brand new, It uses rubber bands for clamps and they are not super tight, possibly a used tube in a new machine or just a bad tube. Hopefully, I will know something Monday. Thank you!