100w Laser tube or PSU dying?

[prcdslnc13]

I have been having issues with my laser for the last couple weeks. I cant tell if its my Tube or PSU. I replaced the PSU in hopes that it would be the culprit but I am still having issues and Im guessing I need a new tube which sucks. My tube is about 17months old according to the date on it and probably has about 50 hours of cut time.

I get some cut power but not really much at all at 25ma. I cant even get through 1/8" MDF. The pictures are of Unfocused Beam spots the one on the MDF is about a half in wide which is about double what it used to be. On the blue tape the full "circle" is on the first mirror. The partial is on the second mirror.

Not really sure what went wrong but boy did it go fast.

[Tech_Marco]

It looks like to me that the tube is dying. With a 100W laser tube running at 25mA, I believe that we could cut through 1/8" MDF at speed of 20mm/s.

There are four major factors that affect a laser tube the most: how old of the tube, how many work hours applied to the tube, water temperature, and current applied to the tube. Most laser manufacturers offer 6~9months or 2~3000hrs working hrs. To me, the working hours is insignificant because there is only 1,728hrs in six months if the laser is running 12hrs per day.


Marco

[prcdslnc13]

The tube is an EFR-F4 100w I got from you guys. I see that its not on the website anymore. Did you have issues with them?

Im trying to understand what would cause such are early failure. Im running a CW-5000 Chiller that never gets over 25degC when operating, Ive never pushed it over 28ma and like I said I probably have less than 50 hours total on the tube. I just run projects in my garage. This isnt production.

[Tech_Marco]

There is high pressure gas inside of the tube. And the gas may leak little by little from time to time. Even though many manufacturer claims that their tube last 5000~10,000hrs nowadays, but I won't take it in serious. In most time, they offer either 6months or 9months warranty only. For small tubes like 40W, they offer 3 months warranty only.

I found that ERF tube doesn't has good beam spot and the beam divergence is a bit more. Therefore, I dropped it about 2 years ago. Now I found a great tube with an excellence beam spot and the divergence is great. The beam from a 100W is about 4mm or 5mm from a 130W or 150W. The beam divergence is less than 0.5mm in about 8ft which is way better than Reci tube. The Reci tube 100W has beam diameter about 7mm or 12mm at 8ft away. When I received my tube on the mid August, I'll test it again.

We have better testing center and equipment: Molectron and NewPort


Marco

[Techgraphix]

Seen from the shape, i would say that one, or both of the "mirrors" inside the tube is broken or even loose.. I have seen simmilar effects with cracked mirrors.
IMHO you can better set your cooling temperature as low as 20 degrees Celcius max. Keep in mind that the temperature at the hottest spot can exceed the temperature that will melt the glue.
I run my tube at 15 degrees but my workshop's temperature almost never raises above 18 degrees in summer.. so condensation or thermal stress is not the case..
What i understood from some lasermanufacturers is that there are a few kinds of gasses in the tube that interact and will form an unusable gass in time so a tube stored for a few years can be almost dead without ever been used, even if there was no leakage.
This is definitely the tube that needs replacement. A good tube gives a dot with the most energy in the middle, diameter approx. 4-5mm for 60-100W. 40W tubes give a somewhat smaller dot, about 3mm

Kees