Operating conditions of DPPS lasers. Overheating problem ???

[pishtak]

Hello,

I'm from Slovakia, I'm 29 years old electrical engineer, and I started to build my first laser projector one year ago. My budget is not very big so at the moment I use laser head from Viasho VB-150 532nm, open-loop scanners G124 driven by Accelerator 124 Amps. I'm pretty old Amiga Freak so I use at the moment LSD1000 from Pangolin running on Amiga and LaserMax by Anthony Barret.

My laser head is sitting on heatsink with installed fan and there is also
temperature sensor on heatsink. When the temperature reaches
30 deg. C the laser head is switched of to avoid overheating.

As I saw on the web that manufacturers of DPSS recomends to operate DPSS laser at ambient temperature from 20 to 35 deg. C (some specifies 40 deg. C). I used my projector cca 4 times for 4-6 hours continuously.

Last time was the room teperature probably high becuse overtemperature was detected and laser head was switched of automaticaly (after few minutes it started to work again).

When I switched it on again after few days I recognized that power is only 20mW (not 150mW as specified). Manufacturer accepted it as warranty claim. I was happy with it, because I think I operated it according their instructions. I asked manufacturer to advise if I did something wrong.
It was only recomended by manufacturer to operate it not more than 4 hours continuously. No advices about heatsinking, cooling etc.

The only company which informs about cooling and choosing heatsink is
Coherent. Also Medialas informs that life time of xxx hours is specified by max 8 hours / day of continuous operation.

I would like to ask about your experiences in operating DPSS lasers (operating temperature, heatsinking etc.)

Is my approach in avoiding overheating acceptable ?

Best Regards from Slovakia.

pishtak

[Hatschi]

Halli Hallo

I can not see a problem for using the laser more then 4h couse there is a overheat protection.
But when the manufacturer says only 4h you have to do so (is it standing in the manual that was comming with the laser?).
What will going deamged they said?

On their homepage I can only see

Output Power stability < 5% over 4 hours

And these lasers have also TEC´s.

Very straingh.

Hatschi

[pishtak]

Hallo Hatchi,

The manufacturer only said:

"You should keep the laser well cooling down with a heatsink, and also you'd better operate it within 4 hours continuously, then rest the laser. That will be good for the laser."

They didn't send me manual. All specifiactions are on their website.

I asked also for recomended thermal resistance of the
heatisnk Rth [°C/W] but no advice from them.

I don't know if manufacturers are measuring thermal behaviour of the laser head. They always specify Tambient = 20 to 30°C but no Rth.

Maybe it is on laser show producers to evaluate right heatsink's Rth

I was in a contact with laser projector producer which is using their laser heads, but they also didn't tell me more details. They are even not sensing heatsink's tempreature.

So will see when I get the laser back, how will it be working. Maybe the laser head from Viasho is producing more heat because driver and power supply is installed in laser head (compact block). Maybe I will have to choose another manufacturer like Lasever or CNI They have dirver and power supply separated form laser head, thus less heat produced ...

Will see.

Best Regards

pishtak