Thernally controlled heat plate for laser banks

[Lifetime17]

Hi LPF,
I had this heat plate hanging around for a while just used it on a bank of 06's. Now the melting point for Indium is 156.6 C / 313.9 F'
I started the removal process at 7:00AM at that setting after an hour no go. So I gradually kept increasing the heat by 10 C , the bottom line is that the diodes were out when the heat was at between 240/250 C . The reason is why the Indium didn't melt is because of the heavy brass heat sink that the diodes were in . So basically when the heat sink temp rises enough to get to the diodes thats when the diodes come out easy. had fun with this and a lot of coffee .
Rich

 

[RedCowboy]

Nice temp controlled heating table.
My blocks were gold coated aluminum, you can scratch through the coating and check, both mine were 05 blocks but I would think they are all the same.
Now that you know how hot it needs to be you can get it done quickly, like you say go a little past the setting to reach the needed temp faster, just like soldering to the pins we don't want to linger with the heat or materials can fail, I have removed diodes with a heat gun and a blow torch ( keep it moving along the long side ) but only from blocks I scored for cheap, I really like that temp controlled plate and you can pre heat the plate to a little above the temp you need to get them out quickly, we will get it down to a science about the time they do something different lol



.

 

[Lifetime17]

Hi Red,
Yes it was time consuming for the first time , but better be safe than sorry. Now that I know the capabilities and what temp this is a real plus. I still have an OA bank and an NUBM03 bank to do. The OA diodes can reach 6 W's + with an efficient diode.
Thanks for the post buddy..
Rich

 

[Cyparagon]

Is there any reason this can't be done with an old toaster oven?

 

[RedCowboy]

Nope should work just fine, just don't cook em more than needed.

I've done the job with a blow torch, just keep it moving along the long side and check with a poker every few seconds.

Of course it would be nice to use the temp controlled hot plate and get it down to a science so as to minimize heating the little jewels any more than necessary.......that said a toaster oven would also work well.

 

[Alaskan]

I would have thought heat that high would destroy the diodes, but the diodes must have also been that hot to put them in.

 

[RedCowboy]

Yes they can withstand being installed, removed and reinstalled likely several times but storage temp. is lower and operating temp. is much lower at least at the case.

I think I will use my heat gun to de-solder the hard board next time.......it has worked well for salvaging surface mount electronics.

 

[Alaskan]

Great, I’d like a block of NUBM47

 

[RedCowboy]

47 is the same as 44v2

 

[lasersbee]

Nice Job Rich...
I like the fact that you only increased the temperature by
10 degree increments until you had a result. Much less
Heat stress on the LDs by not going over the temerature
required to remove them.

I've found a toaster over is difficult to control the actual
inside heat precisely without modifying it with some
electronics to monitor and control that heat.
Found that out when I built my SMD PCB Re-Flow Oven.

Jerry

 

[Lifetime17]

Hi Jerry,
It was a great project to determine the specific temp to harvest these diodes from the bank.
If you can modify an electric toaster oven to get these temps needed that would be great for a reflow oven .
Great idea.. By gradually increasing the temp is the way to go. Rushing through a project like this is a recipe for disaster at a great loss.
Rich

 

[hakzaw1]

great info ya'll.
First 'harvest' must be scary... thanks for finding the best temp. need to write that down somewhere..

len