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Slotted Heat Sink Instead of Set Screw Heat Sink?

smana

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Joined
Nov 2, 2022
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Has anyone tried to machine an aluminum heatsink with undersized bore (slightly smaller ID than the OD of the copper module for an interference fit) and cut a slot lengthwise through the aluminum heatsink to produce an open gap.

When pushing the copper module into the aluminum heatsink bore, open the gap with a large blade screwdriver, push the copper module into the center, and then pull out the screwdriver and let the tension hold the copper module in place?

This would produce greater contact all the way around the two metals when compared to a set-screw which pushes the copper module to one side of the aluminum bore.

However, it is possible that when the slot is cut, the precisely machined aluminum bore may expand or contract slightly due to the stress relief provided by the slot (internal work-hardening stresses which the aluminum heatsink rod experienced during the original cold-roll process).
 





smana

Member
Joined
Nov 2, 2022
Messages
50
Points
8
Gentlemen, thank you for those examples of heatsinks! All of them are much better, IMHO, than a set screw which leans the entire copper module to contact only one side of the aluminum heatsink bore (which, IMHO, is less than ideal).

However, I was wondering if any of us who have used a round aluminum heatsink at the head of a laser pointer ever used a slotted heatsink (with undersized bore) instead of a set screw. There is no room at the head of a laser pointer for bolts to cinch the slot closed - this would make the aluminum heatsink too big for most laser pointer hosts. The copper module must be held by expanding the slot, pushing in the copper module, and releasing the tension - and thus, no bolts needed.

This way, no bolts are required and no press-fit is needed - although press-fits are nice, it becomes much more difficult to separate the copper module from the aluminum heatsink if a burned-out diode needs to be replaced.
 
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I don't know if it will help, but I have also used these, otherwise you may want to have your ideal parts made.

Also you should consider the clamping force you can get without the addition of a gap closing screw based on the material characteristics and your tolerances and the thickness of the mount, remember a little heat sink compound goes a long way.

 




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