Advantages / disadvantages of direct press fit?

[Multimode]

Hi All,

Looking at most builds and custom heat sinks, they appear to use the axixs module.
A direct press 'must' give better heat transfer, so why aren't there more direct press out there?
I'm about to fit a M140 and will machine up a sink to make this a direct press, but if there is a good reason not to then I may use a axixs

ATB
MM

 

[Blord]

Advantage direct press : better heat transfer, lesser parts, better finishing of the thread.

Advantage module : change module with diode if you don't like the output/beam, etc.

others may add more arguments

 

[TheReddish]

I love direct press, for one reason, the duty cycle becomes limited by the driver at that point on most heat sinks. Good driver sinking you get a laser you can leave on till the batteries do dead. if you don't like it, press it out and replace it with another diode .

 

[Eudaimonium]

Direct pressfit heatsink designs are mechanically more secure. With module design you always risk the set screw failing and have your module fly out of your laser, or being crushed into it, and damaging the driver or diode or both.

While thermal solution of direct pressfit method is marginally better, in practise it's not something to genuinely worry about.

As Blord said, direct pressfit heatsinks generally have a higher quality machined M9 threads for the lens, unlike Aixiz modules which are made of brass then nickel electroplated.

 

[sinner]

Direct Press also refers to "NO AIXIZ MODULE REQUIRED" type of heatsinking, thus eliminating the use of BRASS As a Primary Heatsink, and replacing with a higher thermal capacity Aluminium OR Copper..

This helps with Keeping you Laser Diode to Run Less hot as it will conduct the heat in much efficient fashion, however on other hand if you're using aixiz housing the heat generated will be LD<---->Aixiz Module<---->Secondary heatsink<---Set Screw

 

[Eudaimonium]

Direct Press also refers to "NO AIXIZ MODULE REQUIRED" type of heatsinking, thus eliminating the use of BRASS As a Primary Heatsink, and replacing with a higher thermal capacity Aluminium OR Copper..

About that,
http://laserpointerforums.com/f54/i-want-copper-copper-copper-well-maybe-not-72698.html

Y'know maybe there is a reason why all the big companies like CNI use brass as primary heatsink material?

 

[TheReddish]

http://laserpointerforums.com/f44/why-does-aixiz-make-thier-modules-out-brass-52092.html also about why brass

 

[Multimode]

As discussed, the material the module or heat sink is made from is less of an issue than having a low thermal resistance path to the outside.
I've never liked the idea of the Axixs module being side locked with a grub screw, this pushes the module to "the other side" of the hole effectivly thermally isolating one side of the module from the main heat sink. (bar thermal compound)

OTOH, If the module was a tapered fit into the heatsink, it could be locked in from the front and give good thermal conductivity as the tapers would be in contact round the whole diameter and length...be a pig to make accurately though.

I'll make a DP from ali and see how it goes.

ATB
MM