Heatsink for Extruder motor?
I've been printing with my new Mk3 for a little over a week. Both PLA and PETG. With PETG in particular, the extruder stepper motor gets really hot. I have yet to measure it (on my list of things to do), but I wonder if that has been the cause of a couple of jams (plastic getting just a bit mushy in the wrong places). It doesn't seem like that kind of heat can be good for anything.
I was considering getting some 40x40mm passive heatsinks and attaching them on 3 sides (top, left right) to see if it would cool things down a bit. But I'm also afraid of the impact of adding any mass to the extruder assembly. That is why I was thinking passive aluminum heatsinks. But even those add mass and could impact print quality.
I'm using the latest RC2 firmware and I know it was supposed to reduce the extruder motor temps a bit (probably turned down the max current or something), but it is still really hot. I know Joe himself said that all should be fine up to 100C, but it just seems like things would be better if it was < 60C.
What do you guys think? What have you done to deal with the excessive heat in the extruder motor?
Re: Heatsink for Extruder motor?
With 3.2.0-RC2 my extruder is noticeably colder than in 3.1.3. 😕
Are you sure that your filament path above the gears is free and that the gears are aligned etc. pp.?
Re: Heatsink for Extruder motor?
The filament alignment is good, but after fighting the first jam for a while I think the PTFE tube on top of the sensor needs replacing (and maybe the other one). I think I found the cause to be not having enough pressure on the bondtech gear tensioner. The assembly manual just said "top of bolt should be close to the surface" which is vague. Any suggestions for testing tension so it isn't too little or too much?
Still seems like reducing the temp on the extruder motor would be good. But I will try to measure the temp sometime and see how bad it is before trying heatsinks. Thanks.
Re: Heatsink for Extruder motor?
The filament alignment is good, but after fighting the first jam for a while I think the PTFE tube on top of the sensor needs replacing (and maybe the other one). I think I found the cause to be not having enough pressure on the bondtech gear tensioner. The assembly manual just said "top of bolt should be close to the surface" which is vague. Any suggestions for testing tension so it isn't too little or too much?
Still seems like reducing the temp on the extruder motor would be good. But I will try to measure the temp sometime and see how bad it is before trying heatsinks. Thanks.
Depending on how fast you print, with 3.1.3 you should be between 55c and 65c.
If you are above 75c, you have a problem, and putting heat-sinks on it, does NOT fix that problem.
eg: My Pickup keeps overheating. I'm gonna put a bigger radiator on it. <--- Totally a stupid thing to do. It might prevent it from overheating, but it shouldn't be in the first place.
Hi, I'm Sean. I used to work on CNC machines.
I try to not make mistakes, but the decision is YOURS.
Please feel free to donate to my filament/maintance fund.
Re: Heatsink for Extruder motor?
Excellent points Sean. Thanks for the 75C max temp suggestion. I'll try to measure it tonight during a PETG print if I'm home long enough. (I have one of those cheap infrared with laser pointer thermometers, but I'm not sure how much to trust it's reading)
Assuming it is printing hotter than 75C, what are some things to do to try to fix the root of the problem? With older stepper drive hardware I would reduce the driving current with the adjustment pot, but the Mk3 has new fangled firmware controlled ones :-). Would too much tension on the bondtech gears cause the extra heat? Should I just run at 80% speed or something? (I was using default slic3r configs in the beta PE).
Thanks for the help.
Re: Heatsink for Extruder motor?
I have the same issue with my MK3. When te room temperature goes up to 30ºC I have continous PLA jams as you can see at these images:
https://www.dropbox.com/sh/6q26njesrvz3nj3/AABttiKzbLdW2-CG0k4SvqASa?dl=0
The extruder motor is totally aligned and I've remplaced the PTFE tube of the extruder and clean the extruder using cleaning filament during 15 minutes.
Re: Heatsink for Extruder motor?
It's getting hot in that enclosure... printing PLA in an enclosure with LEDs in a room that is 30 degrees C will cause issues.
Re: Heatsink for Extruder motor?
I think I pinned down the problem. I was downloading the new 3.2.0 firmware and realized that in the zip file the only *.hex file included is for the Rambo1.3, but in github there is also a Rambo1.0 and more importantly an Einsy *.hex file. I went back and checked and when I updated to RC2, I only downloaded the zip file and therefore only had the Rambo1.3 hex file, so that is what I installed on the printer. Ooops. I'm surpirsed it worked as well as it did (prints were coming out OK).
So last night I upgraded to the official 3.2.0 for Einsy and the extruder motor ran much, much cooler. I grabbed my cheap IR thermometer and it showed right around 50C. Much better :-).
The moral of this story is to make sure you install the hex file version that matches your electronics :-).