Extruder Motor getting too hot  

Re: Extruder Motor getting too hot

While the motor will work just fine at the "too hot" temperature, the problem will be when that heat travels down the shaft. It heats up the bond tech gears which then softens the filament. This softened filament will then flex, deform and cause jams.

I know that and that's why this thread is still alive and discussed. But we have also people here which are new and don't have any jams/clogs but are worried about hot extruder. My recommendation is never change a running system.

Re: Extruder Motor getting too hot

For the moment I didn't experience any problem with printing. But the fact that my previous printer was able to extrude perfectly as well without the extruder motor running that hot makes me think something's not right. Even if the temperature is within the maximum temperature of the stepper, clearly this is not ideal.

I'm no expert in stepper motors so I'll leave it like this, but I'll add heatsinks on it to help a little bit.

Re: Extruder Motor getting too hot

Question to all who installed heat sinks on the extruder motor.
How effective are they? How much cooler does the extruder gets after the upgrade?

Re: Extruder Motor getting too hot

I too have been experiencing the problems others have outlined in this thread. Jams, clicking extruders, extruder motor that is too hot to touch, etc. Completely frustrating. This doesn't seem like a corner case either, as many people are experiencing this same thing. I've done everything from update firmware to replace the Noctua with a stronger Sunon fan, printed and installed R3 / B7 parts, install a new E3D hotend, and alter many of the settings within Slic3r to reduce the max volumetric speed and retraction settings. Nothing works.

While I know some forum goers are trying to help when they say "mine is just fine, not hot at all," and I appreciate their help, the situation is getting more and more infuriating since those of us with the problem have no way of solving it aside from maybe treating the symptoms with heatsinks or fans on the extruder motor. It seems totally unacceptable that this is the product we're left to deal with. Prusa support asked me go revert to v3.1.3 firmware as a test, but that was just as bad. Waiting to hear back from them again now. 🙄 😥

Re: Extruder Motor getting too hot

My hot-extruder issue seemed to be fixed for the most part :
Mostly by re-doing the gear tightening and making sure the idler frame can move smoothly. Make sure the idle gear is lose and is easy to move, if not, unscrew the idler frame holding axis screw going into one of the corners of the stepper motor frame a bit. If the idle frame does not (almost) fall down on its own weight check if you have installed the included washers to make sure the 3d printed idler frame and extruder frame are not touching and grabbing into each other. Then re-tighten the idle gear following the prusa guide. I did end up tightening it like 2 or 3 full rotations more after that, but not as much as I did before. My screw heads now stick out of the frame just a tiny bit.

0.25mm nozzle :
So I stepped the game up a notch and installed the 0.25mm nozzle and set of to print some small DND characters.
I was amazed by the detail you can get! But I started to have problems again with printing. Specially when printing multiple characters in one go.

On thing I noticed is that when pulling out the jammed filament it did not grind the filament, and you could hear the motor stepping. It has perfect grip without grinding out the filament. Also when I would cut of the end of the pulled out filament and reload it again it would directly load without problems or jams. So the nozzle itself doesn't seem to get jammed with something. I inspected the pulled out filament pieces and noticed they all had a rather large bigger diameter chunk.

It almost seems like the filament is not getting liquid enough anymore to get pushed through the 0.25mm nozzle and starts to collect in the heating chamber. I tried to increase the temp from 210 to 220. It would print a bit longer in general but still get stuck. This all is with the prusa filament it came with (lovely silver for detailed DND character prints btw!)

So I started to think again it could be the filament, but it also printed fine a few day's ago... so that would be kinda strange.
I now have an other theory what might be the problem. My printing environment now is a bit high on humidity (61%). So it could be the filament cought up to much water? I opened a fresh spool of colorfabb PLA white. First print went perfect! See also the picture above, the white filament doesn't build up as much as the silver one.

Humidity test :
So I will try out an spool drying trick with the prusa PLA silver spool and see if that solves the problems I have with that spool.

Re: Extruder Motor getting too hot

Lovely DND figures you got there!

Regarding the jams - are you printing in a warm/hot environment?
I read about jams caused wit PLA in hot conditions, where the extruder cooling was not sufficient and caused light jams.
That's said to happen only with a combination of PLA and warm ambience.
Would explain that the PETG printed fine.

The new R3 extruder design is supposed to improve cooling and solve this issue.

Cheers!

Re: Extruder Motor getting too hot

hi georg.s2

I have already upgraded to R3 (even made my own modded version : https://www.thingiverse.com/thing:3032939 ). I also replaced the PTFE tube inside the heatbreaker (and made it a tiny bit longer). But when inspecting the old PTFE tube it looks totally fine so I guess that wasn't really the problem either.

I know printing PLA in closed enclosure results in stepper motor getting really hot, close to the glass temperature of PLA (and so do the bondtech gears), resulting in molten jams at the entry of the PTFE tube right under the gears. But the jams that I'm having now are (what seems like) inside the hot-end and not the nozzle as the nozzle continue's to ooze out for some time. See my first picture of my previous post, the last few layers are all small droplets of liquid filament still oozing out, but no new filament is being molten. The ends of the pulled out filament also seem not fully molten. They still show the a bit of the teeth markings on them, but deformed or folden over.

Re: Extruder Motor getting too hot

Update :
Yesterday I put the gray filament in the oven @50C for a few hours (~3). Started the print again. But this morning (~12 hours in the print) it jammed again. I also see no noticeable difference, maybe a bit less stringy. Pulling the filament out it has an other one of those bigger diameter tips (like on the photo's before. And the nozzle itself oozed out fully. When loading white filament it directly started extruding white.

So, putting the filament in the oven and reducing the water % in the filament did not help with it getting stuck. I think the silver prusa filament is just not that good for 0.25mm nozzles. And might contribute to hotter motor's since it will create an growing half molten blob on the end of the filament that it needs try to move to the point where it causes so much friction that it won't move down enough anymore to be molten again.

Again a blocking tip, nozzle oozed out fully as can be seen direct extruding white as I loaded white filament (only little dot of gray at the start).

Re: Extruder Motor getting too hot

I'm seeing pretty much exactly the same thing on my MK3, no enclosure used. With no filament load my E-axis motor gets too hot to touch. I haven't tried the GCODE to drop the motor current, but that was where my mind was looking so I'll try that tonight. My newly upgraded MK2.5 never gets past barely warm, even after a 26 hour print with heavy use of retraction, and it and the MK3's extruder are setup the same with R3 parts. This has been the most frustrating part about my MK3, and has cost lots of filament. I love most of the other features, but I really have a problem with stepper motors that are too hot to touch when not printing in an enclosure. I'll give the GCODE a try and report back.

Chief

Last night I tried several prints . . . in my case the extruder motor was reaching it's peak temp about 30% in to my hour long print. So I used this as the sampling point for all 3 tests.

1) With PETG filament reached 55c, could not hold on to the motor. Bed 90c / HotEnd 240c
2) No filament, still reached 55c, Bed 90c / HotEnd 240c.
3) BondTech 2nd gear flipped up, so there was zero drag on Extruder Stepper, reached 52c, Bed was at 30c and HotEnd at 240c, I should have kept the bed at 90c, but wanted to get a good IR pic of the stepper. Will try it again tonight with the Bed at 90c.

So it's not a stretch now to say the motor is getting very hot with zero drag !! Can someone else confirm this please, thanks
Test 3.jpg

Re: Extruder Motor getting too hot

Just adding a data point, my extruder motor gets to around 50C when working on long prints (24hr+), and I've found keeping the alignment and tension on the extruder gear important to maintaining a good feed without the filament riding up one side of the gear causing over-extrusion and twisting.

Re: Extruder Motor getting too hot

My motor was getting insanely hot, so I replaced it with a much better motor. For those in the US (or who can find a similar thing), I would absolutely recommend this motor off Amazon:

https://www.amazon.com/gp/product/B00PNEQKC0

It was all of $14, and stays NICELY cool even while printing the longest of print jobs. It's much stronger than the stock motor, and as such, it's a dash longer. But it fits fine on the extruder to the degree that I will likely replace my other motors with this one as well. Wiring is perfect. It's not noticeably louder. And the wiring is easily long enough to reach.

For the cost savings, I was thinking there might be a caveat, but I haven't found one, and I've had much fewer problems with this one.

Re: Extruder Motor getting too hot

Wow its the price of a meal! I had assumed that these were expensive based on the cost of the kit. It makes me curious what parts of the kit brings it up to cost a grand?

Re: Extruder Motor getting too hot

All told, you have to factor in a markup for customisation and profit. They have the motors labeled with the Prusa name (Prusa loves to see his name on things 😉 ), and the cables are made in lengths to fit the design. But also, in the kit, there're a LOT of parts. The Einsy board isn't cheap. Nor is the heat bed or the power supply. Those are your biggest expenses apart from the basic metal frame.

Add in parts here and there (printed parts for about $80), bolts and nuts and screws (easily $40 worth or more), linear bearings, good quality steel rods.

You get to about $550 or so. Which leaves a reasonable markup for profit that helps pay for design work and administration and support. When you get to the assembled kit, the additional $250 pays for assembly, testing, and the additional warranty.

You could buy and assemble the parts yourself for less if you went piecemeal, but given that you'd be buying one-offs, and generics, you might only JUST come out ahead (no volume discounts). And you'd still have to factor in your time for sourcing all the parts and replacing the ones that don't meet up to spec.

That said, once you HAVE the kit itself, you can find replacement parts and/or upgrades as needed relatively cheaply.

Re: Extruder Motor getting too hot

The only business I've ever run failed in a few years, so I have no business second guessing Prusa. I was out of order to make that comment about cost, I apologize.

Re: Extruder Motor getting too hot

The only business I've ever run failed in a few years, so I have no business second guessing Prusa. I was out of order to make that comment about cost, I apologize.

I don't see the need for an apology. It is a fair question to ask, you just may not get an answer. I do know that the Einsy board and the BondTech gears, if purchased retail, will set you back $160 which is 20% of the cost on just 2 parts.

Re: Extruder Motor getting too hot

The only business I've ever run failed in a few years, so I have no business second guessing Prusa. I was out of order to make that comment about cost, I apologize.

I don't see the need for an apology. It is a fair question to ask, you just may not get an answer. I do know that the Einsy board and the BondTech gears, if purchased retail, will set you back $160 which is 20% of the cost on just 2 parts.

The BIGGEST markups I've found on parts have been on the motors and the LCD display (which is a $10-$15 display at best). But part of that could be tariffs or different part costs in the CR vs here in the US, and part of it could be QC requirements (i.e. it has to meet a particular specification to be considered 'worthy' to sell). But hard to say.

The Einsy is definitely the big ticket item. I've found bondtech gear variants like those for $5-$10 retail. But nothing replaces the Einsy board. It's the most specialised piece of the lot.

Re: Extruder Motor getting too hot

I started running into this issue on my MK3 purchased about a month ago. The motor is getting uncomfortably hot, extruder is skipping and prints are jamming. Can anybody confirm a solution?

Looking at dropping the Vref on the extruder stepper and/or getting a new motor. Have disassembled and cleaned the entire extruder complex and nothing seems amiss.

Re: Extruder Motor getting too hot

My motor was getting insanely hot, so I replaced it with a much better motor. For those in the US (or who can find a similar thing), I would absolutely recommend this motor off Amazon:

https://www.amazon.com/gp/product/B00PNEQKC0

It was all of $14, and stays NICELY cool even while printing the longest of print jobs. It's much stronger than the stock motor, and as such, it's a dash longer. But it fits fine on the extruder to the degree that I will likely replace my other motors with this one as well. Wiring is perfect. It's not noticeably louder. And the wiring is easily long enough to reach.

For the cost savings, I was thinking there might be a caveat, but I haven't found one, and I've had much fewer problems with this one.

Does it have the same specs as the original motor, as in micro stepping ability, etc?

Re: Extruder Motor getting too hot

Looks like the above posted motor is rated at 2A but the stock one is 1A and you are likely underpowering the new motor unless you have made Einsy adjustments. Not to mention the added weight of the larger motor.

Re: Extruder Motor getting too hot

I downgraded my firmware from 3.4.1 to 3.2.1 and managed to finish a 7h22m lithophane print where previously I could only get about 2 hours into the same print before jamming. The extruder motor was too hot to touch when I checked on it around 4h, seemed to be hotter than when it was jamming previously, I'm thinking maybe it's something else in the firmware?