Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Laser Pointer Store

Heat-sink question

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Likes
938
Points
113
Wasn't sure where to ask this so here it is.
I don't understand this heat-sink:


What I mean by that the front half has a small shelf for the 9mm to fit into but it only goes in the lip no more than half way so the rest sticks out and the other half has just a small hole with no lip so when you screw them together there will end up being a gap instead of how a normal press fit is flush. Don't understand why the lip isn't deeper and also the back piece hole is just wide enough that the diode pins are almost touching the wall so you would have to solder the wires to the inside of the pins and still won't be able to get heat shrink tubing over the connections without it rubbing against the wall and likely ripping off the diode pins. ????????
Should I drill the hole a bit wider and lose some heat sinking when the diode is still creating a gap or what? This seems very very strange especially when you are talking about a 3W+ build. If you can't tell the halves screw together.
 
Last edited:

TaterMay

New member
Joined
May 16, 2015
Messages
350
Likes
59
Points
0
I believe it would be best to get Mohrenberg's input on this. This is his heatsink, right? Maybe he can explain the design a little better.
 

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Likes
938
Points
113
He must be out today so I brought the question here as the build just needs an answer to what's up with this. Would be done in minutes if I had a good answer to my questions.
 

TaterMay

New member
Joined
May 16, 2015
Messages
350
Likes
59
Points
0
Yea, I feel ya. I would be a little concerned as well if the diode was hanging out some AND there was space between it and the back half. That's not to say anything is necessarily wrong with this heatsink. There could just be something we are overlooking or are unaware of. Hopefully someone else will chime in.
 
Joined
May 14, 2013
Messages
3,798
Likes
505
Points
0
Well that is an odd one, if the hole is really too small to solder leads and heat shrink them and still fit through the hole, then I guess if it were me I would drill the hole a little larger.

I wonder if Moh had someone in China make a batch of these and maybe they weren't machined quite rite.

Alan
 

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Likes
938
Points
113
He hasn't contacted me yet which is fine. I don't expect anyone to hang out 24/7.
I also asked if maybe I got the back half for a 5.6mm by accident just in case that one is different but the picks look the same to me.
A normal 12mm build would have 5he diode flush with nothing touching the back where the pins are while this just sits perfectly in the hole of the front piece but will fall right out if you tip it. Dont know if there's more heat conducted this way if I make the back piece hole slightly bigger to get the wires through with the rest of the diode back still pressed up against the back half with some air gap between the pieces or the regular way. It's not like I want to blow a 9mm. If I don't hear from him by tomorrow morning I guess I'm going to make the hole slightly wider for now and hope for the best. I can always get the 12mm heat-sink but its not a good idea to keep messing with a diode. Just want to know if this is fine and I would like other seasoned members to weigh in on what they think.
Moh is a great guy and I don't want anyone thinking I've got ANY issues with him.
 
Last edited:

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Likes
938
Points
113
Drilled it out slightly and tightened the heat sink halves and it's working of course but would certainly like to know what others think about it. Don't want to run it long.
 

Laser Chick

Well-known member
Joined
Jan 26, 2015
Messages
1,266
Likes
181
Points
63
My gut feeling is that it was the wrong heat sink for the diode, a part was maybe missing or that it was not machined correctly. I might be totally wrong though :/
Anyways good luck with the build, I can see that you know exactly what you are doing and I wish you the best that it is correct so that you don't pop the diode. Enjoy :beer:
 

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,607
Likes
950
Points
113
The sink sandwiches the diode between the two halfs and is an extremely good sink. You should not have had to drill anything out. The one you pictured is for a 5.6mm diode not a 9mm diode. Was that the problem?

Also it is not press fit the diode slides in the pocked and yes the depth is only half the deepness of the diodes base so the bottom when screwed on sandwiches the diodes base for the best thermal contact possible. I think if the one you pictured is not the one you actually received you did not quite understand the way it works. This is one of the best heatsink designs I have used.:beer:
 
Last edited:

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Likes
938
Points
113
Haven't heard from Moh yet. Hope he is just having a good time somewhere:)
 
Joined
Aug 30, 2008
Messages
6,927
Likes
412
Points
0
I hadn't noticed any difference with the back halves of the heatsinks :/

if there is a larger 9mm version of the back half, I will send you a replacement.

Edit: I was exploring my inner Jesus and pretending to be a carpenter this weekend.
 
Last edited:

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,607
Likes
950
Points
113
The back is the same for both 9mm and 5.6mm diodes only the front with the diode pocket is different.:beer:
 

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,607
Likes
950
Points
113
Yea I think he is talking about how the base of the diode actually stick out a little higher than the pocket of the diode. What he may not realize is that if it was flush or even deeper it would not sandwich the base of the diode and there would be awful thermal transfer. I think he wants the two inside bases of the aluminum to touch.
 

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Likes
938
Points
113
Ummmm I'm right here guys;) If the pins are really supposed to be that close for a 9mm I sure hope no ones pins get ripped off. They will really need to pay attention down the hole that their shrink tubing doesn't catch after making a perfect thin solder connection. Everyone can't solder this well and the shrink tube better be tight. Decided I wasn't going to take any chances and made a VERY slight increase in diameter.
Of couse I wouldn't expect it to be flush or deeper, it would defeat the whole purpose.
 
Last edited:

DTR

Well-known member
LPF Site Supporter
Joined
Jun 24, 2010
Messages
5,607
Likes
950
Points
113
Yea if it is one of the new diodes with the off center pins you do want to be somewhat careful when screwing it together. I usually pull the leads through and sit the diode flat on the base then screw the top down on the diode so the leads will not have any twisting action on them. if you are trying to set it in the pocket then screw the base on the pins that would be tougher.:beer:
 




Top