WLASER 50mW Handheld: Ehh.

[daguin]

Ahh. I've been operating under the assumption that the shorter the distance between the diode and a chunky bit of heatsink the better. My bad, then.



When first turned on, it would lase briefly in TEM00. After it hopped, was turned off and allowed to cool for ~10 seconds and turned back on, it lased for maybe a second or two in TEM00 then switched to TEM01. This leads me to believe that it may be a manufacturer defect (like you said) being exacerbated by a buildup (even within acceptable limits) of heat - what's your take on this hypothesis? Forgive me if I'm beating a dead horse; I observed this behavior and am just curious.

-Trevor

I absolutely agree that your laser was defective and should be replaced.

TECHNICALLY, this mod hop was caused by the crystal or crystal mount heating up. It just was not cause by excessive heat. It was caused by "normal" heat. That's what identified it as "faulty."

The "proximity" of the heat sink to the heat source is a factor. However, heat travels through a good heat conductive metal (brass, silver, aluminum, etc.) MUCH faster than we can easily imagine. It also travels MUCH faster through the metal than it does from metal into the air. That's why it is so important for the heat sink to be as massive as possible. The heat sink must "hold" the heat long enough for it to dissipate into the air to cool.

Peace,
dave

Peace,
dave

 

[Trevor]

TECHNICALLY, this mod hop was caused by the crystal or crystal mount heating up. It just was not cause by excessive heat. It was caused by "normal" heat. That's what identified it as "faulty."

Okay, that makes sense. When I said "even within acceptable limits," I meant normal (since any normal buildup of heat is still a buildup). Glad I'm not going crazy.

The "proximity" of the heat sink to the heat source is a factor. However, heat travels through a good heat conductive metal (brass, silver, aluminum, etc.) MUCH faster than we can easily imagine. It also travels MUCH faster through the metal than it does from metal into the air. That's why it is so important for the heat sink to be as massive as possible. The heat sink must "hold" the heat long enough for it to dissipate into the air to cool.

Great explanation, I felt bad not quoting it.

Thanks. :beer:

-Trevor

 

[sandidgepatrick]

ive got a few 50mw like this coming from wlaser...we power test ect....

 

[Crashpc]

In a short therm use, there is needed high specific thermal capacity of the material. This feature is directly connected to the type, mass and amount of the material. You have to get the heat out of heat source quickly. The heatsink should be able to do it. But If you don´t radiate this heat out into air, you fill this capacity, which will make stop cooling the heat source. This is why you need good radiator (great surface area of the heatsink) to get the heat out to not acumulate. This is good for long term use.

If I´d build some custom laser, It would have massive head with shape like this:
PicFront - heatsink.jpg

 

[electron]

That would be pretty hard to do with most of your lasers since they don't have all the safety features the FDA requires. I would just like to know how this is possible without aperture shutters, key locks, led indicators, 5 seconds delays etc...

That maybe be so, but there are other vendors selling similar and have no issues.

 

[Pontiacg5]

That design is still crap, if the diode was contacting the heatsink like it should than the heat could dissipate into the larger thermal capacity of the metal host without having to move across the crystals and everything else. It probably was a crystal alignment issue as fast as it started hopping, but the design did not help it out at all.

And no, heat does not just instantly move to all points of a metal object when one spot is heated. If so then eating hot soup with a spoon would be very difficult, as well as many other things, mostly to do with cooking. The tailcap, aparature cap, and battery sleeve for that matter really add negligible heat dissipation capabilities to a host design.

 

[sandidgepatrick]

this unit ( 50mw) was a new product of wlaser..it soon will be eliminated .....i first wanna see whats going on inside the host...we be recieving some soon for testing..

 

[UKNOW]

lol,packed in a padded envelope,means a failure activity,look forword to getting some good news from this kinda testing

 

[brtaman]

Thanks for the review twhite. Your utter shock at the insulated module reminds of this: http://laserpointerforums.com/f45/wth-newwish-you-use-your-brain-31174.html

VERY old thread in which I ranted about the insulating air surrounding the module in a NewWish style pointer. Quite a shock to see isn't it? :crackup:

Basically the conclusion, with less heatsinking the crystals heat-up faster, allowing for a burst of high but unstable power. Perhaps a favoured characteristic of the more questionable brands in photonics.

Some modules which I later tested (inline with Igors results), could not "peak" with the added heatsinking. Characteristics were slow ramp-up with relatively stable albiet low Po, of course with a greatly diminished "peak" and general power output.

 

[daguin]

That design is still crap, if the diode was contacting the heatsink like it should than the heat could dissipate into the larger thermal capacity of the metal host without having to move across the crystals and everything else. It probably was a crystal alignment issue as fast as it started hopping, but the design did not help it out at all.

And no, heat does not just instantly move to all points of a metal object when one spot is heated. If so then eating hot soup with a spoon would be very difficult, as well as many other things, mostly to do with cooking. The tailcap, aparature cap, and battery sleeve for that matter really add negligible heat dissipation capabilities to a host design.

reductio absurdium

I didn't say instantly. I didn't say to all points of a metal object. A green handheld pointer is designed to be used in short burns with a "rest" in between. The "rest" is to allow the heat to be distributed to the rest of the sink. They are NOT designed to be burned like a labby.


Your cooking utensil analogy is flawed

You can use a metal spoon with hot soup because you put it in for a short time and then take it out. Just like the "duty cycles" of a green pointer. If you left it sitting in the hot soup, your spoon would soon be the temperature of the soup along its entire mass.

Any other objects used in cooking that are designed to be continuously in contact with the heat source have insulation on the "handles" so they can be used. The entire metal of the utensil is heated.

Peace,
dave

 

[wlaser]

Thank you for great advice, becuase it is new, we need ur suggestion to improve our quality! Promise for ever, totally refund includingshipping fee if u do not satisfy THE quality! Appreciate THE supporter here!

 

[sandidgepatrick]

i like the 50mw units in this discussion....they are great....way overspec. no heating problems that i see.. i will will for sure be buying more...for the price vs output...awesome..

 

[Pontiacg5]

You would buy that laser? The one that has absolutely no heatsinking?

This is just the same cheap china lasers from a different reseller. The only thing I can say that is good as that this reseller at least has excellent customer service. I guess you could try to get a good one, but I wouldn't count on it.

 

[daguin]

You would buy that laser? The one that has absolutely no heatsinking?

You continue to exaggerate to extreme. I do not know why, but you do.

Your statement, above, is patently false.

Peace,
dave

 

[Pontiacg5]

Obviously you do not know much about thermal dynamics or heat capacity, so I will leave the above statement as it is, unedited.

 

[daguin]

Obviously you do not know much about thermal dynamics or heat capacity, so I will leave the above statement as it is, unedited.

LOL! Fair enough

Peace,
dave