Dim3nsioneer

@Yellowshark: Thanks for the link. It's a quite nice summary of all possible effects. It might be worth to include it into the troubleshooting guide at some point. However, I'm aware of all these effects and I'm pretty sure that one of them is indeed the case for my issue. The thing is, I'm using really high-quality filament (Diamond Age) with very low fluctuation of the diameter (1-2um). But still it might be these fluctuations. Next thing I will do is to repeat the print on the UMO with settings as similar as possible. And what could I do if it is the leadscrew itself? On my UMO, I replaced the leadscrew with a ballscrew and really got rid of such effects. Unfortunately, I can't use a ballscrew in the UM2 as there is no space for a coupling between a standard NEMA17 motor and the ballscrew (due to the fact that the print bed goes really down to the bottom). @Mikey: Lowering the speed is a work-around but no solution IMHO. And in my case with this exact filament it does not make the banding disappear completely. I'll let you know when I have the solution...

I just found something which might help to solve this case: When I switched off the fans to test something for a different issue, a close top surface was suddenly not closed (compare the middle and the right print in the picture below). So it has something to do with cooling...

I continued on this issue and switched to a Sky Blue filament which seems to show the effect best. In the meantime I got a new z nut from Ultimaker as the old one showed some significant play in all directions. The new nut hasn't got the play but doesn't solve the case neither. The following picture shows three test prints. From left to right: old nut, new nut, new nut without fans. The print settings were: The=210°C, Tb=60°C, 3731mm/s. Obviously the filament is very sensitive to cooling compared to other colors. Shutting the fans off is not a solution as I got a very nasty line spacing at the top fill. I already tried: - Increasing flow by decreasing filament diameter settings to produce rather over extrusion - Higher (220°C) and lower (205°C) temperature - setting up new PID parameters for the hotend (achieved stability +/-1-2°C) Nothing of that worked... So I'm open for new ideas... :???:

You may try to put the white dial of the feeder into a middle position as this is the best setting for UM2s since March this year.

@arapp: You may try if you can push the filament through the heated hotend manually. If you feel a significant resistance, your problem is with the hotend. If you don't, it's likely with the feeder. Don't forget to test with and without the Bowden tube. If the filament is changed with the 'change filament' option, a very fine string is deposited in the Bowden tube. This string can make your filament being stuck in the Bowden.

Yep. After double-checking: Same here.

Dachte schon, da hat jemand etwas im Sinn... Stichwort Dual Extruder...

@Jonny: Did you cross-check with an old Cura version? I remember that I had many small movements during printing of the Ultirobot at a certain height. It might have been the height you showed in the image.

Realistisch gesehen wahrscheinlich etwa Dezember/Januar. Das hängt natürlich davon ab, viele Interessenten vorhanden sind und wie gross die Summe des Bedarfs ist. Am besten schicken Interessenten mir eine PM mit der anvisierten Menge und wie dringend es ist. btw: Steht das SH bei Deinem UM2 eigentlich für 'Single Head'?

I recommend to search the Ultimaker forum with Google instead of the (useless) internal search: just use the term "1.75 site:umforum.ultimaker.com" and you will find many posts about this topic.

The odds are close to 100% if both strips are from the same lot and the whole lot is faulty... Could it be that your second printer was assembled by fbrc8 and they have a different source for the LED strips than the production in the Netherlands?

It will be interesting to see if the filament gets stuck or not. According to information I have from the Ultimaker R&D department they tried some ceramics but had the problem that PLA got stuck to the ceramics when melted.

IMHO there are indeed exactly these two applications which are worth running a dual extruder setup. However, both of them need a slicer software which is capable to have different settings for the two extruders such as infill percentage, print speed, retraction on/off etc. Cura is not yet there. The pink unicorn edition will be able to do this most probably. But this piece of software will take some time to be finished. Until then one has to use e.g. Slic3r. That's maybe the reason why not many people are using dual extrusion on their UMOs. @mjmdavis: Before you decide for an UM2 you have to know that the present UM2 hotend is optimized for printing PLA. To my personal experience the quality of PET-prints (including various materials like XT, PET+,...) is better on an UMO. I guess it is due to the higher heat capacity of the UMO hotend which results in a more stable temperature.

Bei Diamond Plastics sind Rollen einfach 100m aufgerolltes PLA und Spulen sind besagte Kunststoff-Karton-Vorrichtung (die durchaus mal auseinanderfallen kann). Den exorbitanten Preisunterschied zwischen 3mm und 1.75mm kann ich Dir leider nicht erklären. @Visual (etwas off-topic): Dieser Thread könnte Dich ev. interessieren: http://umforum.ultimaker.com/index.php?/topic/5712-pla-von-diamondage-plastics-sammelbestellung-schweiz/

This behaviour is indeed intended. Usually the bed needs more time to heat up than the nozzle. So the bed can be selected alone, e.g. if you use a filament which should not stay too long heated up (e.g. Woodfill or Lay-Wood). Don't forget, it's a preheat option and not a maintenance option for the hotend.

AFAIK there is PP filament but it needs something like 290°C IIRC. I doubt that it will ever work with a standard UM2 hotend.

@cadsign: Du kannst ihn Dir ausdrucken: https://www.youmagine.com/designs/alternative-um2-feeder-version-two Wenn ich Deinen anderen Post richtig verstanden habe, druckt Dein UM2 ja mindestens zeitweise ok. Damit müsste es für die Teile von Robert's Feeder reichen. Bis auf zwei M3-Schrauben sind die Teile entweder gedruckt oder im Original-Feeder vorhanden.

@Dirkels: Be aware that PU is not in a shape yet where you can really test. As Daid mentioned it is far from complete.

Bei Ultimaker direkt kostet das Kit 'nur' €245.

I guess it depends on the material. I get more hairs with one color of a high quality filament brand than with another color of the same brand with exactly the same print settings. The nozzle of my printer is clean.

There is one major difference between the belts on the UMO and on the UM2: the first ones are of the type MXL and the second ones of the type GT2 (trapezoidal profile vs. half-round profile). Backlash is significantly smaller for the GT2 belts. Thus, direct drive isn't really necessary on the UM2. Furthermore, tightening the belts is easier and better defined on the UM2 due to special distance holder parts for the motors and integrated belt tensioners in the xy-blocks.

They forgot 'dedicated', 'superior' and 'unique' ...

I recently saw the Robox at an event. It's print quality is not comparable (yet) with an Ultimaker. But the dual-nozzle feature is indeed quite interesting.The printer uses the small nozzle for the outer shell and the large nozzle for the rest, except for very small prints where it uses only the small nozzle. But the swapping of the nozzle also takes some time as changing the extruder on other machines.

Sorry, I didn't check it there. In most cases I want to access a site on Youmagine I get an error message (from the Youmagine server, not from my browser...) So I usually don't even try Youmagine-Links anymore... but thanks for the information!

@gr5: Nick and me are still hoping to get the PLA brand...