I want copper copper copper! (well... maybe not)

[lasersbee]

Heck, you might even check eBay.



I disagree. As long as you use the same host for each one. Especially if you use a common host that has seen a lot of use.



That's just it, we already know all these things. What we want to know is which of those characteristics makes a better sink for our application. It is no problem to find out the thermal conductivity and heat capacity of the metals. We're just trying to see which combination of specific heat and thermal conductivity works better to keep the running temperature of a high power laser diode lowest.

I bold that because Cyparagon's sig is a good point, "A problem well stated is a problem half solved."




Again, this is not true for what we are trying to do. We aren't testing the metals, we are testing the different metal's ability to heat sink our application.



That might be ideal, but I think the differences are either going to be big enough that it is clear that one or two metals are doing such a better job that you won't need that level of detail, or you will have them so close that it will be clear that it just doesn't matter which metal you are using.

It is like your laser power meters. Ideally you should have different calibrations for different wavelengths, but we all accept the industry standard +/- 5% and ignore that if we are testing red or green or violet, that we aren't in the ideal zone of ~445. (I think that is right.)

We just accept that it is close enough for our application.



As long as he doesn't have a ceiling fan cranked up in one test or an ambient of 60F one day and 80F another, I don't think air currents are going to be abig factor.

With all due respect (and I'm not being sarcastic - I mean this honestly) I think you are applying some of the things that are important in designing and using your power meters to a test here that is much less delicate.

I think temp gradients are going to be significant enough that those elements will be negligible unless there are big differences in ambient or air flow.

:beer:

Well... I guess you are right and I am wrong....

I stand behind what I posted...
It must be because I'm a hands on perfectionist...:beer:

You guys can do the tests any way you want.... I don't
build Lasers and have no clue about heat transfer and
heat differentials...


Jerry

 

[piferal]

If you want to experience, I think is fine and funny.

But I do not understand why experiment with a nickel heatsink, when we know that apart
from being expensive, hard to find, Etc. but mostly it has a very poor thermal conductivity
compared to other materials with which you want to experiment, aluminum and copper.

The Steel is a bad idea also because it also has a poor thermal conductivity.

Thermal conductivity

Nickel 91 W/m-K

Steel 43 W/m-K Depends on the metal alloy

Aluminum 237 W/m-K

Copper 401 W/m-K


These data are approximate, as it depends on the purity of the metal or some alloy, temperature, etc.

But serve to give an idea of ​​the differences, especially between the nickel and the other 2 metals.


I suppose that the thermal conductivity for an heatsink for the type we needed here, is very important, or the most important.

If we need evacuate effectively outward the heat generated by the diode, and we put the
heatsink in the midway of the system (between the module and the host) and if it has a
poor thermal conductivity, and furthermore is one that has the largest mass, the heat will
not evacuated outwards effectively, then the disaster will be insured.

Maybe I missed something here :thinking:

 

[BShanahan14rulz]

I still say doing away with modules would net more gains, but I do have several PC heatsinks that can be donated to the cause, if they can be of use. From the looks of it, it looks like you will be needing bar stock, not pre-made and useless for our purposes heatsinks, but the offer is there, PM if needed. Standard celeron and low end amd heatsinks made of extruded alu of unknown alloy. Copper server sinks with copper soldered stacked fins for 2U server.

 

[tsteele93]

Well... I guess you are right and I am wrong....

Well thanks for taking the time to read it and agree with me.

I stand behind what I posted...

Wait... :thinking:

It must be because I'm a hands on perfectionist...:beer:

So... How does that work with the compromises you must make in your laser power meters?

Does it eat at you that they are only really calibrated accurately at around 445nm and yet people use them to measure 405, 532, 635, 650 and up?

Does it eat at you that the LPM's are +/- 5% which means a 1.5 watt laser as measured by your meter might be putting out anywhere from 1350-1650mW?

Does it eat at you that people scratch their coatings and you tell them it won't make much difference in the readings?

Does it eat at you that people use your LPM in a room with a ceiling fan on, or an air conditioner or heater kicking in during the test?

Because it seems like laser metering is kind of an inexact process at the hobbyist level.

You seem comfortable with some pretty big swings in data there, but testing the heat of a diode needs to be more controlled?

You guys can do the tests any way you want.... I don't build Lasers and have no clue about heat transfer and heat differentials...

Wow, that is odd. I would think that you WOULD know about that with your laser power meter business.

 

[tsteele93]

If you want to experience, I think is fine and funny.

But I do not understand why experiment with a nickel heatsink, when we know that apart from being expensive, hard to find, Etc. but mostly it has a very poor thermal conductivity compared to other materials with which you want to experiment, aluminum and copper.

The Steel is a bad idea also because it also has a poor thermal conductivity.

Thermal conductivity

Nickel 91 W/m-K

Steel 43 W/m-K Depends on the metal alloy

Aluminum 237 W/m-K

Copper 401 W/m-K


These data are approximate, as it depends on the purity of the metal or some alloy, temperature, etc.

But serve to give an idea of ​​the differences, especially between the nickel and the other 2 metals.


I suppose that the thermal conductivity for an heatsink for the type we needed here, is very important, or the most important.

If we need evacuate effectively outward the heat generated by the diode, and we put the heatsink in the midway of the system (between the module and the host) and if it has a poor thermal conductivity, and furthermore is one that has the largest mass, the heat will not evacuated outwards effectively, then the disaster will be insured.

Maybe I missed something here :thinking:

I agree with you, but RHD's angle is that we really Rent carrying much of the heat out to the air. Mostly we are just trying to fill up a chunk of metal with as much heat as it can hold and since metals with decent thermal conductivity are out there that have higher specific heats, perhaps they could store more heat and be a better sink.

His angle - if I understand correctly - is that the heat sink in our application really is THE sink for our diode and so little air exchange is taking place that it is more important how much heat the metal can hold vs how fast it can move the heat away.

I am not on the same page with him on this, but I like the idea of testing to see if it could be true, it is thinking out of the box and an interesting exercise that might help understand heat sinking our lasers better.

:beer:

 

[rhd]

Since all hosts are made differently it is not important
to place the Test Heatsinks into hosts. As a matter
of fact your Metal Heat properties tests would be more
accurate without the hosts....

I disagree. Part of my initial theory is that the nature of the host itself changes our primary concern from being one of heat transfer, to heat absorption. If you leave the host out of the equation, then you've just got the heatsink itself exposed to the outside air. I have no doubt that copper would perform the best in this scenario. However, once you encapsulate our heatsinks inside a host (often a host made out of steel), then my hypothesis is that the host itself becomes a limiting condition that changes the game from one of "rapidly moving heat" to one of "holding as much heat as possible". The essence of my argument surrounded the scenario that we actually encounter here frequently, which is a heatsink inside of a host, as opposed to a heatsink directly exposed to air.

But I do not understand why experiment with a nickel heatsink, when we know that apart
from being expensive, hard to find, Etc. but mostly it has a very poor thermal conductivity
compared to other materials with which you want to experiment, aluminum and copper.

I think we're at the stage with this thread where people are jumping in late, and no longer reading the OP. If you had read the OP, you'd understand why I think Nickel will perform better than copper as a heatsink in many of our build scenarios. You don't have to agree with me (a number of people in this thread don't), but in terms of why I want to experiment with nickel, it is very thoroughly explained.

I still say doing away with modules would net more gains (...)

I agree. One of the largest benefits that we could implement now would probably be to go entirely press-fit.

Does it eat at you that the LPM's are +/- 5% which means a 1.5 watt laser as measured by your meter might be putting out anywhere from 1350-1650mW?

That math can't be correct.... ?!?

 

[lasersbee]

So... How does that work with the compromises you must make in your laser power meters?

Does it eat at you that they are only really calibrated accurately at around 445nm and yet people use them to measure 405, 532, 635, 650 and up?

Does it eat at you that the LPM's are +/- 5% which means a 1.5 watt laser as measured by your meter might be putting out anywhere from 1350-1650mW?

Does it eat at you that people scratch their coatings and you tell them it won't make much difference in the readings?

Does it eat at you that people use your LPM in a room with a ceiling fan on, or an air conditioner or heater kicking in during the test?

Because it seems like laser metering is kind of an inexact process at the hobbyist level.

You seem comfortable with some pretty big swings in data there, but testing the heat of a diode needs to be more controlled?

Wow, that is odd. I would think that you WOULD know about that with your laser power meter business.

We are not discussing Laser Power Meters. We are discussing
the suggested use of metals other than copper or aluminum
for heatsinks because it was suggested they could "hold" more
heat...

It seems it eats at you that have no clue as to how we acually
calibrate our LasereBee Products or all the wavelengths that
were used to design our products.

It seems to eat at you that >$2000.00 Profesional LPMs can have
5% tolerances.

I seems that our LPM products eat at you enough to post inaccurate
information about scratched surface coatings...

I seems that you have never read the User Instructions supplied
with our hobbyists LPMs because warnings about air currents are
clearly stated on page #3 of your LaserBee A LPM...

It seems to eat at you that our LaserBee products read within
2% of our Lab quality Newport LPM...

BTW... +/-5% on 1500mW is 1425mW-1575mW...

I seems to eat at you that your TROLL attempt was a FAIL....

Wow.... maybe you should get back on track on this thread
rather than try to derail it by attacking myself and our
products...

I disagree. Part of my initial theory is that the nature of the host itself changes our primary concern from being one of heat transfer, to heat absorption. If you leave the host out of the equation, then you've just got the heatsink itself exposed to the outside air. I have no doubt that copper would perform the best in this scenario. However, once you encapsulate our heatsinks inside a host (often a host made out of steel), then my hypothesis is that the host itself becomes a limiting condition that changes the game from one of "rapidly moving heat" to one of "holding as much heat as possible". The essence of my argument surrounded the scenario that we actually encounter here frequently, which is a heatsink inside of a host, as opposed to a heatsink directly exposed to air.

So a 2nd series of tests could also be done with insulation on the Heatsinks
to keep the heat in the sink... Then in a host and it would let us know how
much the Hosts aids in heat removal.


Jerry

 

[jakeGT]

Does it eat at you that the LPM's are +/- 5% which means a 1.5 watt laser as measured by your meter might be putting out anywhere from 1350-1650mW?

I agree with RHD and Jerry.... you might want to try that one again...

For someone who knows an awful lot about everything basic math shouldn't be hard...

 

[rhd]

So a 2nd series of tests could also be done with insulation on the Heatsinks
to keep the heat in the sink... Then in a host and it would let us know how
much the Hosts aids in heat removal.

That's a good idea.

For that 2nd series, what would you use as insulation for something small like a heatsink?

 

[lasersbee]

You could use Fiberglass wool or even the Foam sleeves
they sell to insulate copper hot water pipes... They come
different diameter sizes and are cheap..


Jerry
(12100)

 

[electron]

A While back the CEO of 4sevens had a very limited number of Maelstrom S12's with copper heat sinked LED's made, I think that was the model number; as he wanted to see how much cooler those high powered LED flashlights would run at.


I believe he said afterwards, it wasn't worth the extra money cause they only noticed a couple of degree's difference on those limited production units, compared to using aluminum heat sinks for the LED's. Thus they won't offer anymore with copper heat sinked LED's. Maybe somebody could contact him and he'd be willing to share some real world experience about them.

 

[tsteele93]

It seems it eats at you that have no clue as to how we acually calibrate our LasereBee Products or all the wavelengths that were used to design our products.

Please enlighten me. I was under the impression that they were calibrated based on a specific wavelength (440nm?) and we just (for the sake of making it affordable) accepted that we were some degrees of error when we were using them to test other frequencies.

Perhaps I am misinformed. Please let me know how it really works.

It seems to eat at you that >$2000.00 Profesional LPMs can have 5% tolerances.

Not at all, I was just pointing out that there are degrees of inexactness that are going to occur when you don't have unlimited funds, and sometimes when you DO have funding.

I seems that our LPM products eat at you enough to post inaccurate
information about scratched surface coatings...

I'm sorry, I just read through this thread and it seemed like you were saying that a small scratch wouldn't significantly affect the readings, just lower them a little. Maybe I didn't understand the thread fully?

I seems that you have never read the User Instructions supplied with our hobbyists LPMs because warnings about air currents are clearly stated on page #3 of your LaserBee A LPM...

Don't be silly! Of course I read them, once you sent me the link to the pdf after I had gotten my unit. I was just thinking that not everyone reads their instructions completely. Again I may be wrong then - perhaps you have never had any problems with your customers not reading the instructions then? I'm sure all your customers follow the instructions carefully.

http://laserpointerforums.com/f64/f...a-logging-stock-now-61644-25.html#post1039850

It seems to eat at you that our LaserBee products read within 2% of our Lab quality Newport LPM...

Why would that eat at me? :thinking: I was just wondering if that stuff bothered you since you were telling us what a perfectionist you were with RHD's test.

BTW... +/-5% on 1500mW is 1425mW-1575mW...

I seems to eat at you that your TROLL attempt was a FAIL....

Wow.... maybe you should get back on track on this thread rather than try to derail it by attacking myself and our products...

Jerry,

I am so sorry that you took my post the way you did. Nothing above "eats at me." Why would I care about any of that stuff? Can you imagine me laying awake at night, unable to fall asleep because an LPM isn't accurate enough? :crackup:

I simply didn't understand how you could be so "perfectionist" about a simple heatsinks test when in your business there are so many real-world imperfections that are considered standard business practice.

I specifically stated that it was the industry standard to have +/- 5% tolerance because I wasn't calling out YOUR LPM. I was just pointing out that in the real world there are lots of inexact measurements we are forced to deal with all the time.

So I just didn't understand why you were so picky about the precision of this test...

As for the +/- 5%, I apologize. I accidentally did +/- 10% for some reason.

Anyway, I am terribly sorry that you took that as an attack on you or your LPM's! I tried to be very careful not to do any such thing.

I hope you understand that a disagreement doesn't constitute a trolling. I would never intentionally troll someone by doing things like poking fun at their choice of words in a post without making any other useful contribution to the post or anything like that! That would be trolling, and I don't do things like that.

:beer:

So a 2nd series of tests could also be done with insulation on the Heatsinks
to keep the heat in the sink... Then in a host and it would let us know how
much the Hosts aids in heat removal.


Jerry

WHY would you make the test further from our reality? Using a known host (or hosts) would better approximate what is happening. I don't think any of us are using hosts that INSULATE the sink. That doesn't make any sense to me!

 

[tsteele93]

A While back the CEO of 4sevens had a very limited number of Maelstrom S12's with copper heat sinked LED's made, I think that was the model number; as he wanted to see how much cooler those high powered LED flashlights would run at.

I believe he said afterwards, it wasn't worth the extra money cause they only noticed a couple of degree's difference on those limited production units, compared to using aluminum heat sinks for the LED's. Thus they won't offer anymore with copper heat sinked LED's. Maybe somebody could contact him and he'd be willing to share some real world experience about them.

That is interesting. It would be great if it is true. Aluminum is without a doubt the most economical choice and if it performed that closely to copper. My curiousity is whether our situation is different enough from those high wattage LED's that it might be different.

As RHD said, the fact we aren't getting as much sink-to-air transfer as some applications might put us in a situation where the specific heat makes more difference than in a situation where you primarily want the sink to be a conduit to some fins or to the air.

Again, I am on the other side of the fence with RHD on this one, but I a, open minded enough and curious enough to be interested in testing his theory.

 

[tsteele93]

I agree with RHD and Jerry.... you might want to try that one again...

For someone who knows an awful lot about everything basic math shouldn't be hard...

I'm sorry, I confess Jake, I am not perfect. I made an error and did +/- 10% for some reason.

It must be very frustrating to those of you who are perfect to have to deal with the occasional error from someone here on the forum?

Thank you for pointing it out so politely to me.

:bowdown:

 

[Wolfman29]

Just a point of input: all of this speculation is based on how long we can keep the laser on before we have to turn it off. That's all fine and dandy - maybe nickel really will help with the amount of time a laser can be kept on. However, we also know that it will drastically increase the amount of time it must be kept off before it can be turned on again for another full duty-cycle.

The question: is that what you want? For my builds, I prefer shortish duty-cycles (45 seconds-60 seconds on) with 30-45 seconds off. That's why I typically use copper when I can - it aids in transfer to the host a lot more than anything else (especially when getting a tight fit to the host), thus allowing it to dissipate that heat faster and be able to be turned on more quickly.

 

[tsteele93]

That math can't be correct.... ?!?

No, I had a brain fart and did +/- 10% for some reason. The correct numbers for a 1.5 watt reading would be that the laser might actually be putting out anywhere from 1425mW-1575mW, assuming that there are no errors for wavelength calibrations.

My mistake. Several people have pointed it out to me!