Replacement extruder motor sd3

You just need a decent NEMA 17 motor.  I replaced the original one that came with my SD3 a while ago with a Kysan 11124090.  This is a much more powerful motor than the original one, but it's also longer, so you might not be able to use the original heatsink and fan because it would hot the rods, when fully at the back.

I say might, because I no longer have the original carriage, so my current setup interferes with the rods by about 1/4", but on the original carriage or other designs, it might not.

Because this is a more powerful motor, it doesn't need to work as hard, so it doesn't get as hot as the original.  Therefore the heatsink and fan can be smaller.  I bough a heatsink/fan intended for chipsets, with a total depth of about 5/8", and it works great.

Do  search for that kysan model on ebay, there must be thousands of them.  You could always pay $15 for one and get it in a couple of days from places like Printrbot, or Amazon.

http://www.robotdigg.com/product/37/Nem … r-heatsink

http://www.makrtoolbox.com/nema-17-size-heatsink.html

Just look at any place that sells  3d printer parts or  Google NEMA 17 hear sink . these are about 40 x 40

a fan would work better than a heatsink.

I re-purposed one of the stock SD4 fans for the X motor (the one that was on the back of the case). a simple printed fan mount that friction fits the bottom of the motor, attach the fan, and no more overheating X motor...

this is the fan mount I used: http://www.thingiverse.com/thing:128526

A fan by itself without a heatsink is inefficient.  If you don't care about noise, then a high peed pan should work, but if you do care about it, then add a heatsink, and you can use a lower speed fan.

You could pick up Something like this, cut it to size and drill the holes. It's aluminum, so I don't think that will be very hard:

http://m.newegg.com/Product/index?itemn … lsrc=aw.ds