Ultimaker 2+ suddenly not feeding

[davek17 0]

I have been 3D printing for about 3 years now and have 3 printers. I upgraded my U2 to a 2+ about 2 months ago, as soon as the kit became available and have been really chuffed with it. Prints were great, reliability good, 10+ hour prints with no issues.

I then tried my hand at some rubber printing and had some good success with that. Changed back to PLA for a customer project and cannot get the printer to work any more.

So the issue is a little odd. basically the filament is not feeding but I am getting no kick back, the actual wheel just stops rotating. If I give the filament a little push underneath the feeder box then things work OK, however if the filament comes up against any resistance all at the knurled wheel stops rotating. Normally you get the clicking as the wheel is biting into the stuck filament but this is different.

So i double checked i'm not using rubber settings.

I moved the tension on the feeder right back up to the top (Although tried bottom, middle and in between)

I have changed the nozzle, rebuilt the hot end, checking everything there, all brand new really since the upgrade.

Filament easily pushes through the nozzle if I manually push it.

Filament moves easily through the tube if I unattach the tube from the hot end.

But if i put it all together it just stops feeding, like I said above, no clicking, just stops.

I read something about the motor being the wrong way, but it has been fine so it can;t be that. Everything feeds the right way anyway.

Just hoping someone can shed some light on it as this is the first time I have been beaten by what is otherwise a wonderful piece of kit.

Any help is much appreciated.

[gr5 2,172]

Most likely the motor is turning but the gnurled sleeve is not. I have a plus but haven't taken the gnurled sleeve off and I'm not sure how that works but for the non-plus machines that is most likely. Possibly mark the sleeve and shaft with a sharpie and then try turning just the sleeve without the stepper moving. If you power up the stepper (have it move 1mm) it will stay "locked" for a minute so you can put more force on the sleeve.

Alternatively the extruder driver is weak. It's common - especially if the electronics get warm and especially with the newer circuit board for um2 printers that the stepper drivers overheat and then they get very wimpy. Removing the cover over the pcb and then blowing a fan on the circuit board helps (you can tilt the printer to get airflow under there while printing - it doesn't matter - it will even print upsidedown). Warm weather hurts (if you don't have air conditioning).

[gr5 2,172]

Oh! Also the gears can strip or get misaligned or what have you.

[davek17 0]

TY for the reply.

So it was a warm day here yesterday in the UK, but 21 degrees I think so not warm really! I'll check the temps of the motor and PCB and try to cool them and see if it helps but I don't think its that because its happening ASAP after startup.

I'll take another look at the feeder box on the back and check out the gears and the knurled wheel too.

Will get back to the thread as soon as i can, busy day here though today (7am in the UK right now)

[davek17 0]

Hi There

So I have been rooting around in the feeder box at the back of the UM" and think I have the root cause here.

If you look at the image, what I did was to remove the back cover and then put the UM2 into filament loading mode, just so I knew the knurled knob was turning the right way slowly.

I then hold the knurled knob and I can easily stop it with my fingers.

So I took a look at the gears, the smaller one can move a little freely along the motor axle, however not enough to lose connection with the larger gear.

The gears are aligned and the teeth in good health.

Then I saw the slippage. It is the small gear that is just stopping and slipping around the motor axle.

So the motor seems fine as it is not stopping, the small gear however is stopping and spinning around the axle instead of being fixed to it. I can see that the axle and gear have a flattened side to ensure they stick together, my smaller gear is simply too easily able to be pushed around and I can freely spin it around the axle with my fingers, like well easily able to do that.

So that's the issue. I have not really done all that much printing since the upgrade so I think this part is suspect.

Does anyone know of a place I can get a replacement or better part?

[davek17 0]

So I have found what might be a temporary solution, not sure how temporary, I will come back and comment in a few days as I have a fair few hours to do on this UM2+.

I slid the small gear off the motor axle and saw that there was some grease on the axle so I cleaned everything up, put a blob of super glue on the spindle and then re-fixed the gear.

Loaded some filament up and as I did that I held the filament going into the bottom of the feeder and heard the normal feint click. Good news as this means the gear is no longer slipping.

So the above might just be some of the tooth oil getting caught on the spindle, it might be a design flaw, or we might just need metal gears or a screw to stop slippage?

[IRobertI 520]

Get in contact with the place you bought the printer from and ask for a free replacement gear under warranty. The newest gears are slightly redesigned to help prevent sliding along the shaft as well.

[spirou 0]

Discovered the same issue last weekend. The printer stopped feeding material at all but with me it was a bit different. The drive gear was not spinning freely on the axle it was only slipping forward and backward. I think grease got onto he stepper axle and lubricated a place that shouldn't. In my case the gear wanted to be as close to the stepper as it could get so I was able to print a little spacer to hold the gear in place. I had to pause the print once to reposition the gear.

https://www.youmagine.com/designs/spacer-bfea204e-7ccd-42e8-a199-dfaf2901bc72

is a little spacer to go between the drive gear and the stepper. Fits tight to the axle.

- Carsten

[gr5 2,172]

And whomever you contact - give them a link to this topic. IRobertI works for one of those resellers and has fixed many of these machines.

[jmoney 1]

man I thought I had a heating problem or something. Was driving me crazy..

same thing just happened to me it was pretty far down.

Gotta print the mod out so it won't happen again.

cheers!!!

[jmoney 1]

oh the good news was that I swapped for draft nozzle, just to see how that works let the filament eating begin