Does anyone use his Pololus stepper driver with passive cooling?

3D Printing
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1

Does anyone use his Pololus stepper driver with passive cooling? Like mounted on a big heatsink or something like that?
I know that sometimes the A4988 work with no active cooling on prusas and stuff, but want to talk about steppers that need cooling like TMC2100 or RAPS128

2

Most chips come with little stick on heat sinks nowadays. They work fine for me but my printrboard has no cooking and it is fine. Drivers run slightly warm at most.

3

The problem is the thermal pad for most of those drivers goes to the board. The plastic package isn’t going to get cooled very well with something stuck to the top of the chip.

4

@Jeff_DeMaagd is right. Many people also run a fan on theirs to ensure that they don’t overheat.

5

Panicatt and Waterott have the right idea for the little driver carrier boards. For the chips with the thermal pad on the bottom, put the chip on the bottom side of the board. That way, you can use a heat sink effectively.

That said, I’ve gotten best results from boards that put the driver on board. I’ve driven a genuine RAMBo hotter and more aggressively, for longer, than any step stick I’ve ever seen, because they use the copper layers of the board to spread the heat like the chip designers intended.

6

Thanks for the info, but I knew all that already. I was explicitely asking for cooling drivers that need cooling with a passive method.

7

TMC2100’s current rating is for fanless, heatsinkless operation.

8

What current rating? 1,2A? Never ever do they operate with no heatsinks… They are the hottest drivers I ever had in my hands…

9

Yes, 1.2A. Trinamic rates them at 1.2A RMS (pulled from TMC2100 data sheet) and Trinamic rates all their stepper drivers without heatsinks or additional cooling - see here:

http://www.trinamic.com/_articles/_common/_files/TRINAMIC_Product_Guide.pdf

on page 8. “As all TRINAMIC stepper drivers have lowest power loss and do not require heatsinks in their full specified current range,”

The TMC2100 is rated for use up to 105C, well beyond what you can hold in your hand.

10

Bet, Trinamic doesn’t had in mind that they will packed on miniature PCBs to fit pololu-sockets :wink: They even convert their own-logic voltage what get them hotter even more. They really can not be handled without cooling…

11

I’ve been hearing lots of reports lately from various people getting thermal shutdown skipping with TMC2100s set somewhat below the rated current limit.

It’s really all about the current setting relative to the rating. Every Mightyboard and clone in the world (~100k of them) runs 4982s or 4988s with just a heatsink and no need for active fan cooling. They also only push about 0.8-0.9A, so it’s not much heat generation.