I have outlined the type of heatsink. Please see the OP.
Sorry, i overread the setting. So its 4 heatsinks for each K16 board.
I now found what i referred to with the holes under the chips... Its this post:
https://bitcointalksearch.org/topic/m.2179575If i understand it correctly it means the holes are filled with heat dissipating stuff so that the chip can connect to the heatsink. The heatsink doesnt have to reach to the chip, its already done in the pcb.
I dont think that asking for prices for different quantities is bad business behaviour. Often they will give a list with quantity to create and the attached price to it. I thought that you maybe have such list.
Forgive my noobness but whats the problem with such heatsink for example:
http://uk.farnell.com/h-s-marston/890sp-01000-a-100/heat-sink-100mm/dp/4105977Its the first result searching "heatsink 100mm". Wouldnt it be possible to drill in the needed holes to attach it at the pcb? I mean the pcb on the other side is flat, theres no parts built in.
The price for these arent low though... i only wanted to ask why such things wont work.
Yes, the thermal vias are necessary to give channels for the heat to pass through to the heatsink. The heatsink physically attaches to the board at the contact patch located directly behind the chips.
The problem with such a heatsink is the ridiculous cost, and hole drilling costs need to be added on top of that.
Also, please note copper standoffs will be required for attaching the board to the heatsink, in order to raise it above the surface of the PCB.
Any heatsink would work potentially, however having the holes pre drilled is a huge timesaver.
If Bkk gives the go-ahead that these will dissipate the heat well enough, given multiple boards stacked together and a fan blowing at them, I'm in for at least 50.
That is correct, there are plenty of options out there, the purpose of the thread is to find the most cost effective solution, which is made possible by buying in bulk.
This particular heatsink is one of the options I am looking at to have custom made holes drilled in. The goal is sub $6 per heatsink.
Edit: quote fail
$6 per heatsink sounds good... though its a bit strange that even at that price the K16 will cost $35 and the heatsinks for it cost $24... I had thought that such things could be pennyware from china or india or similar. Looks like i had a wrong view.
What do you mean with copper standoffs? I thought the heatsink only has to be flat at the bottom, put thermal paste at it and mount it together with the pcb...
I thought that drilling wouldnt be a big problem. I probably could do it myself in some minutes... marking the holes at the back and drilling... aluminium should be possible to drill very easily.
What i dont like so much at the moment is the inflexibility... one batch has to be ordered, thats it... that means you have to plan everything beforehand which i cant... i dont know how many chips i will buy in total. Thats why i would have preferred if bkkcoins could sell the heatsink together with the sets. So i wouldnt need to plan and i could reorder.
I think i will search a bit now... by the way... the heatsink could be everything from 5cm-the border with the holes at the border... so maybe 4x4cm to 0.1x0.1cm. Ill check if there isnt a very cheap offer.