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This is not my video, but this is exactly how I do it.

Make certain your laser diodes can fall free from the block when you push them out..... because if you set the block on a flat surface, the indium on the edge of the diodes backing plates will re-solidify in the bottom of the sleeve..... not good.

I don't bother with the ir thermometer although I do own one, I just heat the back of the block with my heat gun and just keep checking with your pick and when the indium melts the diodes will push right out and fall free into your aluminum foil catcher..... you can favor one end of the block then the other to make it easier, just keep checking with your pick.


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Alien Laser said:
I have 3 brand new NUBM-71 diode blocks i can not extract any i try 400C and nothing the not coming out any suggestions!!
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I used my smd hot air gun and sat the array on wood blocks rather than clamping it in a vice or anything thermally conductive.

Even tested the raw output of each diode before and then after extraction to see if I had damaged any.

Really had my nerves shot for the first one, but all was good.
 
Put your heat gun close to the diode block, don't hold it way back ..... The block will absorb heat and melt the indium.

I have also used a blow torch, but put the flame on the sides of the block and keep it moving back and forth and constantly push with your pick so the moment the indium melts you can push the diodes out.
 
Alien Laser said:
I used a blow torch for 5sec and all fell out i was waiting to push it out 😂 i will see to sell some since the are new 0hrs $40 NUBM47-A4
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I wonder what is better for the diodes, the longer process and prolonged exposure of a heat gun or the rapid heating and shorter duration of a torch 🤔
 
Alien Laser said:
I used a hand torch and all pop out in 5sec i touched one diode and it was not even hot pretty 😎
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Sounds like the torch may be a safer method.

Been a while since I extracted one of these blocks, but I remember it taking 5mins or more and everything including the diodes were hot 🥵

I saw no degradation running my heat gun at its max of 500c, and will definitely be trying a small torch next time around.

Did you happen to do any before and after power tests?
 
paul1598419 said:
I have a reflow station as well. You might want to get one of these.
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I think an argument could be made in favor of using a a torch in this situation.

It looks like the diodes are exposed to less heat for a far shorter duration of time.

When we solder diode pins the goal has always been to keep the heating time as short as possible.

From what alien posted above, his diodes fell out and weren't hot. This happened in seconds vs several minutes.

High heat to the mount for a super short duration may be the way to go for a safer extraction. Granted the mount is heated and not hitting the back of the diodes.

Seems counter intuitive at first, but the more I think of it, I'm liking this idea.
 
The reflow station is good for other purposes than just to remove diodes. Mine has a temperature controlled iron which is great for what it was intended to do.
 
paul1598419 said:
The reflow station is good for other purposes than just to remove diodes. Mine has a temperature controlled iron which is great for what it was intended to do.
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Agreed. I have an 852D workstation and it's a great tool for pretty much 99.9% of the work I do.

Bought it to reflow PS3 graphics chips, and then used it on these diode blocks to extract.

My point was that it may be more stress to the diodes using this tool given the mass and surface area of the mount used.

Other than that, it's my go to tool for depopulating pcbs, and soldering smd components.

Definitely a must have🍺
 
Alien Laser said:
How long will it take to extract diodes using a reflow station hot air gun ?
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Mine has a max temp of 500c and takes approx 4-7mins of heating evenly with the largest tip and airflow set to its highest.

By the time the diodes break loose, both the block and the diodes are at the melting temp of the indium.

This is why I like the idea of rapidly heating the block, it's much faster and from what I gather, the diodes internal components aren't seeing the full temperature.

The block and the contact points are seeing that heat briefly, which theoretically would be less stress.

The only issue I see is if not careful, one could far exceed a safe temp.

As long as the block is upside down and level they will just fall out anyway. Just have to be careful not to hit the back or face of the diodes with the open flame.
 
Careful with excessive heat you will either melt bondwires or the LD crystal will become detach from base both leading to low power or dead diode. I'll fetch the pictures of the heat curve used to solder/desolder them. Heatplate is your friend. And also careful when you eject them a hard drop will also move LD cystal out of place while hot.

Here is the soldering temperature all take a total of 4-5 minutes
And no more than 1 minute at high heat.
1000036857.png
 
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Darktron said:
Careful with excessive heat you will either melt bondwires or the LD crystal will become detach from base both leading to low power or dead diode. I'll fetch the pictures of the heat curve used to solder/desolder them. Heatplate is your friend. And also careful when you eject them a hard drop will also move LD cystal out of place while hot.

Here is the soldering temperature all take a total of 4-5 minutes
And no more than 1 minute at high heat.
View attachment 78084
Click to expand...
If I remember correctly, with the blue diodes the chip is not bonded with indium as seen in NIR 808's for example.

I read a discussion here on the forum some time ago where it was mentioned that the chip is fused with silver using a high energy pulse from a laser to mount them.

To my understanding the chip would burn up long before you could break it lose with heat.

A simple experiment could be performed on a dead LD to confirm.
 
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