80 watt Reci laser beam problem

[OK Robotics]

Hi,

In April of last year, I bought an 80 watt Reci tube and a 1800x1200 x-y stage and all the other parts to build a large laser system. It took me a few months to get it all put together, and I have been using it since, but something has always bothered me. When cutting through thick material, the left edge always gets the surface scorched, and the cut always leans to the left. I cannot get this to go away no matter what I do with the alignments and focus. Yesterday, I took the tube out of the machine to do some burn tests to see what might be causing this, and discovered that the beam is actually 2 beams that are a few millimeters apart and one is much stronger than the other. These beams diverge slightly over distance, and by 8 feet away, I have to double the power to be able to mark the paper. I am attaching a photo of the burn mark left by the laser about 2 inches from the output optics.

Any idea as to what may be causing this and how to correct it?

Thanks,
Nathan

beam.JPG (5.59 KiB) Viewed 2925 times

[Tech_Marco]

Nathan

Take a look of the output "window" and check the lens if any dirt can be found. Then, clean it with very fine & soft cloth but never scratch it by any mean


Marco

[OK Robotics]

Marco,

I checked that when I found the problem. There were a few specks of dust on the window, but after cleaning I still got the same results. The photo from the original post is after cleaning. I used the microfiber cloth that came with the laser glasses and wrapped it around a q-tip to get inside the aperture and clean the window. The window is clean with no scratches.

This tube has been causing this problem since I first bought it, I just finally figured out that the problem was the tube and not my alignments.

Nathan

[Tech_Marco]

Look like there is an issue on the mirror (inside of the tube). If so it is impossible to fix it without the manufacturer involved. I have an idea but not sure if it work. I'm thinking that by using two short focus lens line up with gap distance of two focus length may be able to correct the issue. But doing so, it cost to buy two lens and may lost 3~5% power. Plus, I never done it before so I'm not sure it will fix the problem

Marco

[OK Robotics]

laser.png (8.51 KiB) Viewed 2885 times

I have drawn a picture of what I think you are suggesting. Please correct me if I am wrong, but isn't this simply going to invert the beam and waste power? I don't think there is any way to fix this problem with external optics as it is something wrong inside the tube itself. Is there any way to have it replaced or repaired be Reci?

[swamidog]

that looks doesn't even look like a TEM01 profile. if you're confident the external optics are clean and you're not clipping on anything, try the same burn test at various power settings and see if the burn pattern changes.

i have seen, on occasion, beam quality change as power levels are increased.

Hi,

In April of last year, I bought an 80 watt Reci tube and a 1800x1200 x-y stage and all the other parts to build a large laser system. It took me a few months to get it all put together, and I have been using it since, but something has always bothered me. When cutting through thick material, the left edge always gets the surface scorched, and the cut always leans to the left. I cannot get this to go away no matter what I do with the alignments and focus. Yesterday, I took the tube out of the machine to do some burn tests to see what might be causing this, and discovered that the beam is actually 2 beams that are a few millimeters apart and one is much stronger than the other. These beams diverge slightly over distance, and by 8 feet away, I have to double the power to be able to mark the paper. I am attaching a photo of the burn mark left by the laser about 2 inches from the output optics.

Any idea as to what may be causing this and how to correct it?

Thanks,
Nathan

beam.JPG

[Tech_Marco]

laser.png

I have drawn a picture of what I think you are suggesting. Please correct me if I am wrong, but isn't this simply going to invert the beam and waste power? I don't think there is any way to fix this problem with external optics as it is something wrong inside the tube itself. Is there any way to have it replaced or repaired be Reci?

Therotically speaking, if it is going through a high quality lens set for image or video, yes it could be duplicated to the output. But over here, we're talking about high power CO2 beam going through a ZnSe focus lens, but not passing through a high pecision focus lens you found in the camera. Considering the beam may diffuse itself rapdily when leaving from the focus point due to inferior in quality of focus lens. So, the beam after being compressed and expanded, I believe that the "flaw" could be absorted away by the beam itself. Well, it's my theory only. I can't proof unless I can test it on a faulty tube like yours.

Regarding the warranty, it is over 6 months and I can't get you replacement. Reci local warranty is 9months. When I imported those tube, there was 2 weeks needed for packing, 30 days for ocean shipment , and about 1 month (roughly) stock time. That's why I offered 6 months warranty to offset those lost from shipping. You purchase April 2013 and it's been a year (12 months). Sorry I really can't do nothing about it .


Marco