Recommendation for Soldering Heatsink for sensitive components (laser diode)

[LiquidLife]

Hi all,

I searched for this on the forum, but couldn't find anything, so here is the question:

I've heard that laser diodes are very sensitive, so I'm figuring I should be using a soldering heatsink to attach to the leads in between the diode and the metal to be heated up and soldered...

Anyone have any recommendations?

 

[Jimmymcjimthejim]

You don't need any special equipment to solder wires to laser diodes. A very hot soldering iron will do the trick if you are able to solder the wires in less than a second. If you've never soldered before, then I would recommend getting some practice first as soldering to something so small can be quite a task.

 

[paulzimm]

I always use a "heatsink clip" when soldering leads onto a diode. But from what I hear from others, once the diode is pressed into the module it is unessary. Better safe than sorry...

 

[Vaporizer]

Heat can certainly damage one. Practice and a clean soldering tip with extra flux works well here. One pin in many cases solders to the diode case pin. It's the other one (isolated) that you can easily over heat. If it get to hot, the heat transfers up the pin to the fine gold wire inside damaging it or its connection. Tin all 4 connections 1st (2 diode & both wires), let them cool and then its just a matter of tacking them together.
The faster you can get in and out the less risk.

 

[Toke]

Heat can certainly damage one. Practice and a clean soldering tip with extra flux works well here. One pin in many cases solders to the diode case pin. It's the other one (isolated) that you can easily over heat. If it get to hot, the heat transfers up the pin to the fine gold wire inside damaging it or its connection. Tin all 4 connections 1st (2 diode & both wires), let them cool and then its just a matter of tacking them together.
The faster you can get in and out the less risk.

Good advice.

Try to heat/melt the tinned wire before touching it and the iron to the tinned pin.

 

[Benm]

Its best to have the diode installed in the aixiz module before soldering, but thats all that is required... provided you have some soldering skills, ofcourse. If you don't, try soldering cheap things first, like wires onto resistor or led leads. It takes time to learn - don't be disappointed if you make a total mess of it the first couple of attempts.

 

[LiquidLife]

I'd rather be safe then sorry; what type of soldering heatsink clip do you use, paulzimm? (Heatsink clip was really what I was asking for.)


All good stuff, thank you everyone.

 

[jkardon1992]

okay just to get this straight;

with the soldering iron, touch the pin of the diode that is in contact with the pad on the driver or wire, do this for a second and then quickly touch the solder to the pin and let it melt over the connection?

so like, you touch the heat to the pin, then touch the solder to the pin after the heat has been applied for a short time? the shorter the time heat is applied the better.

to be safe would you suggest soldering wires in between the diode and the drive?


Or was the alternative suggestion to basically put a blob of solder on each end of the connection (diode pin and wire/driver) then put them together and apply the iron?

 

[Toke]

Or was the alternative suggestion to basically put a blob of solder on each end of the connection (diode pin and wire/driver) then put them together and apply the iron?

Yes.

You put solder on the iron first, just a small blob.
The wire is tinned by touching with the iron, then applying the solder to the contact point and let the wire suck it up.
Tinning pins is done by quickly running the blob on the iron over the pin.

And for FSM's sake, practice on something else than diode and driver first.

 

[jkardon1992]

Yes.

You put solder on the iron first, just a small blob.
The wire is tinned by touching with the iron, then applying the solder to the contact point and let the wire suck it up.
Tinning pins is done by quickly running the blob on the iron over the pin.

And for FSM's sake, practice on something else than diode and driver first.

Okay, i thought putting a small amount of solder on the iron was tinning it. i didnt know you can tin the actual solder, as that is what you use to tin the iron.
So basically, put solder on iron, put iron on contact (where the diode touches the wire) and let the wire soak up the solder from the tinning which connects the two? i thought you would touch the iron to the pin, heat it, then touch the solder wire to the connection


oh and i deffinetly plan on practicing, but connecting two wires seems very easy in instructional videos, is there anything could practice that would help in this specific application?

 

[jkardon1992]

and would you guys also suggest putting hot glue over the whole thing to keep it sturdy?
i heard that suggestion somewhere but i forget where

 

[LiquidLife]

Yeah, that makes sense...

Put the blob of solder on the pin of the diode to tin it which will make it easier to heat it up quick when you actually solder the wire to the pin, as the solder acts as a heat bridge.

Probably want to put some flux on it first though, that way you don't have to heat it up as much the first time, keep the heat at a minimum.

Yes.

You put solder on the iron first, just a small blob.
The wire is tinned by touching with the iron, then applying the solder to the contact point and let the wire suck it up.
Tinning pins is done by quickly running the blob on the iron over the pin.

And for FSM's sake, practice on something else than diode and driver first.

 

[Bionic-Badger]

What they mean by tinning the leads is that you just coat the pins and the wires with some solder beforehand. That way when you do the final soldering, the solder you add just bonds to and melts the solder that has already attached itself to the wires and pins.

The thing with heatsink-clips or whatnot is that you're apt to fry your diode with additional objects you attach to them because of ESD, or other problems. You may even end up welding the heatsink to the solder blob and need to desolder it. Then you'll be pissed to death having to apply much more heat to the diode to get your heatsink off or deal with other problems. These laser diodes can take quite a bit of heat punishment. Hell they're passing 500mA of current through like a 50 gauge wire without burning up. They'll stand a half second of heat to melt some solder a few millimeters away.

The best way to do it? First, practice on some dead diodes or other components. Then after you're comfortable with that, make sure your diode is in the heatsink (aixiz module or whatever), tin the leads, and then get your helping hands to hold the heatsink and the wire (one at a time) exactly how you want them to be positioned. Then you can either put some solder on the iron and bond the wire and pin together, or feed it some solder while you touch the two with the iron. Just do it quickly, and you won't need to worry about heat issues.

 

[jkardon1992]

just ordered a pair of helping hands, im gunna practice on some other stuff to get the hang of soldering. i feel better now