What kind of heatsink is best ?

Hello !
I have a 250mW 650nm laser and I start needing an heatsink to use it for more than 2-5minutes (laser engraving machine).
I found two type of heatsinks for 12mm laser on eBay and I wanted to know which one you think is the best.
Here is the first one and here is the second one.
I think the firs tone is the best but I wanted to get your advice.
Thanks !

The one with fins will dissipate the heat much faster and keep it cool for longer. Refer to the graph on this article.
https://www.pa-international.com.au/index.php?option=com_easyblog&view=entry&id=12&Itemid=177

we had a third test rig with the extruded aluminium heat sink with finns

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shown in yellow



the fins give the heatsink more surface area in contact with the surroundings, therefore there is more exchange of energy and a faster cooling rate.

Those China ones tend to have really bad tolerances which can give poor thermal contact. I really like these. It is a clamp design.
Heat Sink for 12 mm Modules

The one with the fins will cool better. If you really want it to run a decent amount of time I would suggest adding a fan blowing on the heatsink.

HydroSean said:

the fins give the heatsink more surface area in contact with the surroundings, therefore there is more exchange of energy and a faster cooling rate.

Click to expand...

Ok, thank you ! I will buy one with fins !

DTR said:

Those China ones tend to have really bad tolerances which can give poor thermal contact. I really like these. It is a clamp design.
Heat Sink for 12 mm Modules

Click to expand...

Thank you I will probably buy this one then.

Blarg King said:

The one with the fins will cool better. If you really want it to run a decent amount of time I would suggest adding a fan blowing on the heatsink.

Click to expand...

I think a heatsink will suffice but if it gets hot I will do it thanks !

Thought I would mention that a 250mW DPSSL isn't going to engrave anything. It might not even be that high in power if you haven't measured it yourself, or had it measured before you got it.

For a non fan forced air application I would think the blades of grass type would be better than the solid runners, as always the taller the better within reason.

Also some have extra waves built into the fins to add to the total surface area, also I have heard the black coating helps somehow.

532 for engraving.... ? the search bar at the bottom will help with this.. ir diodes are a lot for efficient for this.. even a 445 would be better

Probably, but from the topic start:

The first item isn't really a heatsink, it's a mounting device used to connect a round module to a flat surface like the back of a heatsink. By itself it will do very little since it has little surface area.

The second item has some fins but also tapped screwholes at the bottom so you can connect an extra heatsink there. One thing that puzzles me is why they made the rectangular cutout between module and bottom though, this would severly impede how effective an extra heatsink can be. It seems to be common for similar modules on ebay.

You'd think it saves material costs, but these things look to be machined out of solid stock material so it would only be extra work to cut that slot out. Anyone have any ideas on this?

It could be die cast. Once it has been polished and anodized, or coated, you wouldn't be able to tell.