kris

I suspect a design flaw rather than a quality problem. Nothing will hold the two halves of the lever together effectively. I guess the casing is meant to do that. There are a few underextrusion problems on the forum where people have traced the cause to the feeder. A screw fixes the problem.

This might be the problem:UM2+ design flaw

A while ago my new UM2+ started suffering from underextrusion. I gave him the normal treatment that I know from the other UM2s; changed the coupler (had lasted for 500h) and cleaned the nozzle. Nothing would help. However I had noticed a single kicking noise from the feeder once. So I opened and checked. Nothing. Assembled it again, inserted new filament and again, a single klicking sound and underextrusion. Opened the feeder again and found this; there is a lever which pushes the filament against the driver wheel with a ball bearing. That lever has two halves and these did separate from each other. The ball bearing got off center incapable to guide the filament. I fixed the problem by drilling two holes and connecting both halves with a screws, thus preventing them from separating again. Prints perfectly again. Hope this will help a few people.

Seit Januar? Ist doch dann ein UM2+, oder? Dort kommt unverstärktes TFM PTFE zum Einsatz. Ist was anderes. Hat bei mir 500h erhalten. Allerdings ist dies nicht die einzige Verbesserung; macht daher eine eindeutige Schlussfolgerung schwierig.

Das ist ein Coupler der ersten Generation. Die aktuelle Variante ist deutlich besser. Glasfaserverstärkes PTFE war beim UM2 vor dem UM2+ standardmäßig im Einsatz, ist also nix neues. Wir haben die Erfahrung gemacht das ein Leckage nicht zwangsläufig auf den Coupler zurückzuführen ist. Vielmehr können sich oben auf der Nozzle Rückstände bilden die eine Undichtigkeit verursachen.

Hi guys Wanted to share some experience on my new UM2+ after 560h of printing. I operate a few UM2s and after approximately 200h of printing I have to exchange the PTFE coupler with a fresh one (30% glass filled). Otherwise; Underextrusion. Apart from that, no major problems. Printing all sorts of materials but never mix on the same machine. For the new UM2+ underextrusion has occurred for the first time after 560h. The new TFM PTFE bushing still looks OK so the cause mighty be found somewhere else. In any case I exchanged the bushing for a new one (not TFM though, still have to source the material). When taking apart the head I noticed that the cylinder which replaces the spring was not installed properly; it was misaligned due to a very tight fit. The TFM coupler had also been squeezed heavily against the nozzle, properly due to thermal expansion. But have to say; a very good performance improvement. I believe it is save to say that Ultimaker listens to people's feedback. Awesome. I use active cooling for the feeders on my old UM2s, so I will not be needing the upgrade kit. But I will upgrade to the new coupler in combination with the constant distance spacer. Cheers Kris

I like what UM did. They have listened to people and improved their products. True to the principal; don't fix it if it ain't broke. And, as I have understood, we are able to upgrade our old machines. I feel this strategy is very fair to customers. Thank you UM.

What is TFM? Still PTFE of some sort?

Hallo Felix Habe gerade Deine Posts gelesen. Wir drucken relativ viel mit ABS und (PLA) auf dem UM2. ABS ist eigentlich nicht schwieriger zu drucken als PLA, wenn man ein paar Dinge beachtet. ABS ist allerdings nicht immer gleich ABS. Gute Erfahrungen haben wir mit Innofil und Easyfil gemacht. Bei Deinem Teil würde ich mal versuchen mit 'retraction off' zu drucken. Ist zwar nachher mehr Arbeit, aber die hast Du bei dem Teil ohnehin. Unter 50mm/s bei 0.1mm musst Du nicht, ist wie man sieht eher kontraproduktiv. Ist Dein build volume geschlossen? Zum Modell selber; ich glaube das es für einen optimalen Druck noch verbesserungswürdig ist. Die Rillen würde ich zb mit einer dünne (0.45mm) Fläche schließen. So bekämen die Stege mehr Stabilität und es entstehen keine Löcher (dh. retraction). Der UM2 ist nicht perfekt, aber alles ist er nicht schuld Wie bei jedem Prozess muss so manches Teil auch dem Fertigungsprozess angepasst werden. Viele Grüße Kristian

Das Problem kann auch Feeder entstehen; Diesen am besten demontieren, reinigen und das Bowden Ende kontrollieren da dieses manchmal stark abnutzt und zu erhöhter Reibung führt.

XT-CF druckt sich prima, erst recht mit dem Olsson Block. Hier kann die Düse schnell ersetzt werden. XT-CF ist deutlich steifer aber die Festigkeit ist in etwa dieselbe; um die Festigkeit zu erhöhen bedarf es Lang- oder sogar Endlosfasern (siehe Mark Forged)

Ein komplett geschlossener Bauraum führt nicht zum Hitzestau. Betreibe zahlreiche UM2, alle komplett geschlossen. Wer dazu druckbare Lösungen sucht wird auf Youmagine fündig. Die Haube kann aus Acrylglas komplett ohne zusätzliche Teile verklebt werden.

Had the same problem one; changed the teflon coupler, changed the nozzle, changed the temp. sensor, nothing would help. I then dissasembled the feeder. The bowden tube inside the feeder was pretty demolished. I cut off 10mm and made sure the transition form the feeder box into the bowden was smooth. No problems after that. Cheers

Used to be ok, but now its back again with 15.04.02: After changing material mid print (pause function) the material retracts 5mm and the machine prints with nothing. The issue was fixed with 15.02.02. Can you fix this?

Did you go through gr5's checklist and maybe give some feedback?

Has the problem been solved?

Mein Feeder ist original. Habe den Fan bei Bronze und Messing verwendet, zu Kupfer bin ich noch nicht gekommen. Aber es hat super funktioniert. Vg

Hatte das gleiche Problem, gerade jetzt bei den hohen Temperaturen. Lösung: ein 60mm Ventilator der bei 12v direkt auf den Feeder bläst. http://ultimaker.com/en/troubleshooting/view/16647-cooling-the-feeder?page=1#reply-112725

Jees...I just realised that I forgot a very important aspect: 6. Turn cooling fans OFF I operate a dedicated UM2 with only ABS and have no problems with warping this way. I didn't touch material settings for ABS, except for the print temperature. That should be as low as possible. Again, everything in order to maintain a constant temperature gradient inside the build volume. There needs to be a fair amount of glue stick on the glass (several passes), absolutely no need to use ABS slurry. This way I regularly print ABS parts to the size of almost the entire build volume.

Indeed, this solved the problem. Cheers

By the way; does anyone know if I can run an additional fan (12V) from the mainboard? It has got a 3Pin Molex connector. If not I'll just use an external power supply.

I have purchased two 60mm fans and designed a printable fan mount. My UM2's are all enclosed with acrylic and I will simple cut out a piece of the acrylic and mount the fan to blow directly onto the feeder. I guess it cannot hurt to cool PLA even below 30C. I have noticed that there is a small deformation of the filament even below that temperature. That causes unnecessary friction in the bowden.

Hi Has anybody considered cooling the feeder? Tried several prints during the weekend. All prints failed fairly early on; at first material flow was OK. After a while every print experience underextrusion that would culminate in 0% material flow. As usual I suspected a clogged nozzle. Cleaned it...several times. Didn't help. Finally I realized that the PLA filament had been flattened by the feeder. The feeder could still grab on to it, but with the new shape the filament would cause significant friction in the tube. No chance for the feeder to able to push it to the hotend. I had previously notice on my UM2's that the feeder wheel would get very warm because it is directly connected to the stepper motor. In addition, due to the climate we had close to 30°C in the room. I then put a fan behind one of the printers to help cool the feeder. Problem solved. I am no considering placing small fans to the rear of the prnter to help keep the feeder/ filament cool. What do you guys think? Any similar experiences? Cheers, Kris

Hi 1. Allways use prim 2. Close up build volume ('green house) 3. Raise bed temperature to 110C 4. Turn of fan (in cura) Constant and relatively high temperature inside the build volume is the key Cheers

In order to minimise warping to an acceptable level you need to do the following: Minimise temperature gradients! 1. Hence increase build plate temp to 110C (only do so once the print has started, otherwise it will take forever to heat up. 2. Reduce print temp as low as possible without compromising strength 3. Most importantly; close the build volume so that heat cannot escape. You can do so preliminary with cardboard. 4. Brim is a must. 5. The provided glue stick is absolutely adequate. Cheers Kris