Exactly HOW is max duty cycle determined?

[JBTexas]

I am guessing that the manufacturers:

(1) Just plug in a tried-and-time tested thing (an assumption), like "90 seconds on, 20 seconds off" or whatever.

(2) Maybe they actually do tests with a thermistor or whatever?

Is there some way we could benefit from this question... is there any hard data (like for a diode / DPSS / driver, it can take x degrees for y seconds?)?

If there IS some reliable data, then maybe as part of the DIY process a thermistor(s) (as small as possible) could be put in certain places, and readings could be made. After all, how do computer manufacturers adjust automatic-fan-speeds?

The thermistor(s) could be taken out when the builder is done with it. OR, *JUST a small thermistor(s) could be permanently mounted, but with access to the leads so that they could be attached to instrumentation.

As a guy just getting into this, I would like to keep a laser on as long as possible... but I'm sure the old-timers could benefit as well.

Food for thought?

 

[Lotus_Darkrose]

http://laserpointerforums.com/f44/how-determine-duty-cycle-63807.html

 

[JBTexas]

Lotus_Darkrose.... Thanks Much! I DID do a search ("duty cycle") but got so many hits... and didn't see this touched on (much) in the existing threads.

That helps.

 

[Lotus_Darkrose]

No problemo.

 

[JBTexas]

Yes; thats a good thread (I think it should be "stickied", if you ask me)(just did a quick, but thorough read-thru).

It yields enough to start thinking about methodology.

 

[Justin]

I can't speak for other vendors but at Laserglow, when we get a new product, we put it on a power meter and a DC power supply and run it until it fails. (Imagine our surprise when the Polaris-1000 just kept going, and going, and going... for hours.) To earn a "100% duty cycle" at Laserglow, a laser has to keep running without losing power for several hours. Lasers listed with 60-90 sec duty cycles (for example) showed power loss or instability around this time, indicating that the laser is not in thermal equilibrium.

 

[JBTexas]

Justin; interesting. The Lyra that I bought from you guys recently (as I recall) is 90/20. I'm a newbie, so it is interesting to me that the pen does actually NEED a duty cycle... that just a 5mw 532 pen NEEDS to cool off. It's hard to explain; but it is part of what makes laser so cool... their intricacies.

Anyway... I was asking mainly for :

(a) The benefit of builders. If *I* ever get around to doing a DIY project, and I decide to go extreme with heatsinking, *how* can I determine if I get a really good/superior duty cycle? ( short of " ...we put it on a power meter and a DC power supply and run it until it fails.")

(b) For those who buy, say, chinese lasers, and those lasers have NO documentation and NO duty cycle posted on the website. The 200mw Gatlin that I purchased recently, for example. O-Like even pushes "This has much a good heatskinking characteristics" (paraphrased); but why mention that if there is no posted duty cycle? Shrug. So I asked here, got some replys, I think I will keep it down to 60/30 or so. From guesswork.

 

[chipdouglas]

your laser glow pen might be ir filtered, and therefore the pump diode will be pushed to get you the 5mw output. Also a factor is the minimal heat sinking in a pen host. so those 2 factors would contribute to a non continuous duty cycle.

michael.

 

[hakzaw1]

You could have found the great thread link given to you by Lotus.
use the search. Bemn has a link in iit that will help you a lot as will most all of the posts there.

here is the link
Merghart.com - Heatsinking laser reference

It a good question and an important one- a good company will give you good answers and a bad one will have no answers. I wrote one china seller about the cycles and they thought I meant bi-cycles---lol


I always want my lasers to live into old age and never run them very long-- that is why we all have more than one. hope this helps. 'when it feels hot (or even warm) or if your laser 'flickers'( could be telling you to re-charge) give it a rest. hak

 

[JBTexas]

Hakzaw1; I *think* I saw that link before, but looked at it again. Yes, and thanks. It's kind of over my head a bit, but only because I don't have any experience with it yet. If I get into a DIY from scratch, I'll make use of it, I have the link archived.

bi-cycles... hehehe... well... um... maybe in a laser that deliberately produces 2+ wavelengths (or is kind of "dirty" ... not chromatically coherent). So there are... lets call them "thermal harmonics", or, simply, bi-cycles. Maybe even tri-cycles ... for the newbie laser builders... because they are not as stable, and their lasers will be even "dirtier", and might fall down. Motor-cycles, of course, are a different story. Gasoline combustion ruby laser drivers. Of course, WE ALL want to make perfect products, so we endevour to have uni-cycles.