Desperate3D

thank you.

Hi Sander, I think the problem is the front fan, it seems that it is not working reliable anymore (starts and stops and does not run smoothly) It seems that the fan was damaged by the nylon incident. I will replace the fan and will see if the problem is solved (most likely yes). The reseller could not help to solve the nylon issue. They said it was due to my negligence, I need to obey the print and stop it if something strange happens which could cause damage to the printer! But I think you will agree, that it is not feasible sitting 26 hours beneath your printer and watch everything is going well. I can very well live with the fact, that the print itself is not coming out well, but the printer should not destroy himself but stop working. Since the reseller (and Ultimaker) did not accept this as a warranty case (the printer is only 4 month old) I bought new print cores and a new print heat (just in case) myself. But I have to admit: My confidence in Ultimaker suffered a lot (using an UM2 for quit some time successfully) and with the UM3 I had only bad luck (so far).

I think I found the cause why the filament is not being pulled back. For whatever reason the end part of the filament was thickened (see picture) and it was not possible anymore to pull the filament through the transparent plastic hose. I removed the plastic hose along with the filament and pulled it the other way around out of the tube. What can be the reason for the thickening ?

Thanks for the hint. I'll give the wedgebot a try. I have never forced the printer to skip this step. And I am using PLA.

General printing in regard of the grinding issue is ok. So I think the pressure (tension) on the feeder seems to be ok, too. Please see a picture of the "nylon" incident. That was really terrible and happened over night during the print of a large part. I think the printer should have some sort of sensors (e.g. the camera) to prevent this kind of problems. Anyway, I managed to remove the destroyed print core and had replaced them through new ones. The print head still seems to be intact. P.S At the moment I am using PLA.

Hello SandervG, it is an UM3 Extended. I mean that the filament is not being pulled back (it sticks still somewhere in the Print-core). When I do heat up the Printcore (Menu->MATERIAL->PrintCore1->Temperatur) than I am able to pull it back and change the material (but this is a very annoying procedure) It worked in the beginning more reliable but now it is not woking at all. I am using a new Printcore because the old one got completely destroyed by the attempt to print nylon. Generally I think it is not a good idea not heating the print core before retracting the material. Look at the picture what happens if you try to change material and repeat this procedure 2-3 times. (at least on my printer)

On our UM3+ Model, we have the problem that on material change the printer will immediately retract the material without waiting for the nozzle to heat up. As a consequence the material will not be ejected. When I do manually heat up the nozzle we can retract the material. Anybody has a hint what went wrong (or is damaged) ? I have already checked the temp. sensor in "Diagnose" and they seem to work. Michael.