I think that I may change my solder temp!

And a few other things!

Some interesting info in this PDF.

SONY LASER DIODE GUIDE

Here are some highlights...

Temperature is one of the primary factor affecting reliability for semiconductor laser diodes. As the temperature of the diode and the surrounding area increases during use, the rate of degradation increases exponentially.

For every 10°C increase in room temperature lifetime decreases by about a factor of 1/2.

Tolerance to soldering heat: Temperature 265°C for 5 seconds

(Although it says this elsewhere: "Keep the solder iron (30W) tip temperature less than 260°C and do not keep in contact for more than 10 seconds.)


Natural fall: Height 75cm Maple plank strike surface 3 times


Note that deposits or dust on the window glass of a laser diode could cause deterioration of the laser diode performance. The following practices are recommended.

1. Do not touch the window glass with bare hands.
2. Use care to prevent damage to the window glass by tools or other objects.
3. When dust deposited on the window glass is to be removed with an air gun, short circuit the leads or use a moss pack covered with a conductive bag.


This was written in 2000, so some of it (like soldering temp) may be outdated.

Note pages 68-69. That would be a neat soldering station!

If you use clip on aluminium heatsinks on the LD leads when you solder them (between the LD and the solder joint) the LD effectively sees less than 100C, even with a 400C soldering iron temp. That's what I do, as my solder (expensive stuff) melts around 320 but doesn't flow nice until around 350. My default temp setting is 350 for small things and 400 for large items.

The common practice is to press the laser diode first into the housing , then solder the leads within 1-2s , the laser diode doesnt even get pass 100C as Sigurthur said..
What i noticed is that Soldering on a case pin is safer because it makes direct contact with case(obviously) also it is very helpful if u bridge the case pin not just to make negative contact but also in case the diode overheats the heat is transferred from the diode pins to the case directly.. so there is a slightly less chance to break the emitter connections..

tsteele93 said:

And a few other things!

Some interesting info in this PDF.

SONY LASER DIODE GUIDE

Here are some highlights...

Temperature is one of the primary factor affecting reliability for semiconductor laser diodes. As the temperature of the diode and the surrounding area increases during use, the rate of degradation increases exponentially.

For every 10°C increase in room temperature lifetime decreases by about a factor of 1/2.

Tolerance to soldering heat: Temperature 265°C for 5 seconds

(Although it says this elsewhere: "Keep the solder iron (30W) tip temperature less than 260°C and do not keep in contact for more than 10 seconds.)


Natural fall: Height 75cm Maple plank strike surface 3 times


Note that deposits or dust on the window glass of a laser diode could cause deterioration of the laser diode performance. The following practices are recommended.

1. Do not touch the window glass with bare hands.
2. Use care to prevent damage to the window glass by tools or other objects.
3. When dust deposited on the window glass is to be removed with an air gun, short circuit the leads or use a moss pack covered with a conductive bag.


This was written in 2000, so some of it (like soldering temp) may be outdated.

Note pages 68-69. That would be a neat soldering station!

Click to expand...

There are eutectic alloys that melt between 117 degrees F - 144 F - 156F - 180F up to around 200-220F. Look up Wood's metal and Field's Metal(among others). Also, I read that they are adding Gallium to solder mixes to lower the temps. I dont know if using a significantly lower temp solder would somehow be a problem though. Maybe the circuitry heats up and melts the solder or something, who knows, it's all Greek to me at this point. I just got started.

tsteele93 said:

For every 10°C increase in room temperature lifetime decreases by about a factor of 1/2.

Click to expand...

I doubt a derating that high applies to modern diodes. Either way, all bets are off when you run them as high as we do.
If thermal degradation is being attacked by an angry mouse, COD is a small thermonuclear device by comparison.

But what does soldering temperature have to do with COD?

I'm sure most people don't actually solder a diode when its operating, and even wait for it to cool down to room temperature before applying power?

Also, you shouldn't worry too much about it really - if you press a diode into a module and solder the leads on afterwards, the temperature of the laser die will remain much lower then the temperature of the leads.

I think the temps in that PDF may be more applicable to soldering in an oven more than anything..

I solder at 245-250c, but its so fast, the diode will never see this, only the pin to which im soldering.

A higher heat means a faster solder, that is unless you are touching the body of the diode
and take forever to make that bond.

Most of the newer diodes we use like 650nm, 405nm, and 445nm no longer use indium
which melts around 140c IIRC. The only diodes I see that still use it are 808nm c-mounts
and 9mm.

It takes approx 4-500c to get the chip off its mount from what ive tested, and have heard
that they are mounted with a high watt CO2 in the first place.

The gain medium itself can take a beating when it comes to high temps.

Benm said:

But what does soldering temperature have to do with COD?

Click to expand...

Running a laser diode near death but being worried about the solder temp? It's like running your car with copious amounts of N2O, but thinking your engine will still last a long time because you change the air filter often.

Perhaps a bit of an odd analogy, but i makes the point.

Most of us operate laser diodes far beyond what the manufacturer rates them for, and that is what causes them to fail, not running hot briefly during installation.

For diode legs, I run my mini 25 watt iron HOT. I quickly tin all leads with 63/37 solder and flux. It takes me under a second to reflow the connections. The diode never gets hot at that short exposure.
Soldering is an art.
HMike

Unless you're worried about your soldering heat destroying the bond wires (unrealistic), then I don't see how you would expect the emitter to be impacted to any unreasonable degree (horrible pun).

Think about how the heat would have to move. Through the pin, onto the other side of the can, up into the bond wires, and down into the emitter. I'll grant you that the case pin operates differently, but even still, that's a very indirect heat path to the emitter. More importantly, if the diode itself is already in a module then it should be hard pressed (another horrible pun) while in that module to see much heat hit the emitter.

I have about 80cc of gallium in a bottle. Maybe I can use it for extreme cold temperature builds. Although I can't seem to get the stuff to freeze even in the freezer because it can supercool so well.

Hemlock_Mike said:

For diode legs, I run my mini 25 watt iron HOT. I quickly tin all leads with 63/37 solder and flux. It takes me under a second to reflow the connections. The diode never gets hot at that short exposure.

Soldering is an art.

HMike

Click to expand...

I am this artist...


Girl With Green Cat by tsteele93, on Flickr

tsteele93 said:

I have about 80cc of gallium in a bottle. Maybe I can use it for extreme cold temperature builds. Although I can't seem to get the stuff to freeze even in the freezer because it can supercool so well.






I am this artist...


Girl With Green Cat by tsteele93, on Flickr

Click to expand...

If you cant get gallium to re-solidify even in the freezer, then the other option would be to 'seed' it with a small piece of solid gallium. That will cause the rest to solidify...... You can buy gallium at rotometals.com.

But....I have about 60grams of gallium, and it was double wrapped in plastic bags, and put into my storage unit, where it is not climate controlled, and since gallium melts at 85 F, it wouldve melted over and over every day during last summer, but when I went to get it and the rest of my elements out of storage in January, it was solid. It was clear that it had melted at some points. So I dont know why yours isnt solidifying even in the freezer, because mine solidified at temps never going under 30 F.

I have it in a drawer right now and it stays liquid even though we keep the house in the low 70's all the time. (Us fat guys like it cold!)

I put a little in a petri dish and put it in the fridge thinking it would freeze and it didn't so I put it in the freezer and it didn't freeze.

When it arrived at my house it was a solid though.

I was hoping it would be fun like mercury but not dangerous like mercury, but it is way messy and leaves a gray coating on everything it touches.

Not sure what to do with it now. I'd like to silver some mirrors or something with it, but I don't see how that would work either with the low melt point. It is all kind of shiny though!

I don't think pure gallium would make solder joints between gold plated pins and copper wire really, at least not at room temperature or slightly above. Soldering requires the metals to dissolve into eachother to some degree.

Metals like coper are actually slightly soluble in normal 60/40 solder, yielding a very strong connection ones the solder joint cools down. This is substantially different from just 'casting' the two wires into some volume of low melting metal.

tsteele93 said:

I have it in a drawer right now and it stays liquid even though we keep the house in the low 70's all the time. (Us fat guys like it cold!)

I put a little in a petri dish and put it in the fridge thinking it would freeze and it didn't so I put it in the freezer and it didn't freeze.

When it arrived at my house it was a solid though.

I was hoping it would be fun like mercury but not dangerous like mercury, but it is way messy and leaves a gray coating on everything it touches.

Not sure what to do with it now. I'd like to silver some mirrors or something with it, but I don't see how that would work either with the low melt point. It is all kind of shiny though!

Click to expand...

Oh there's cool stuff you can do with gallium! One old trick is to buy a spoon mold, pour your gallium into the mold so it solidifies(but thats the problem here isnt it?), then keep it in the frig til needed. When someone comes over, give them a cup of tea, and the gallium spoon to stir it with. The spoon will melt in their tea! You can retrieve the gallium later too.

Also, gallium readily alloys itself with many metals, so a cool trick is on youtube, where you put a small amount(1gram maybe) of gallium liquid onto the top of an aluminum can, then scratch the aluminum through the gallium puddle to break the oxide coating over the aluminum, then wait. The gallium will literally soak into the aluminum like water soaking into paper, and it will dramatically weaken the aluminum, to where you can push your finger right through the aluminum like it was wet paper! The entire top of the can will be weakened. There'a another video of the same guy doing this to the heatsink from a computer, and it turns the thick aluminum into unbelievably weak material. I mean the whole heatsink too!

Gallium is also used to alloy with aluminum at about 10% Ga ratio, and it prevents Al from instantly forming its protective oxide coating, so the alloy will liberate Hydrogen from water, and you can put a tank of water with this Ga, Al alloy inside, and it will constantly produce Hyrdrogen for your car! After its done and broken down, you can still extract all the Ga from the tank and use it over and over.

Ga will wet glass(and skin), and other stuff too. There is a Ga alloy called Galinstan(Ga, In, Tin(Sn), which becomes liquid at around -25 F or so, and its used as a safer filling for thermometers, among other things.

But if you want to solidify it, add a small solid piece, or sell it to me in liquid form!