Dim3nsioneer

Can you please give us some more details about your printer? You refer to preheating which is usually used for a heated bed. Do you have an UMO with the heated bed upgrade kit or an UMO+?

Can you exclude someone was manually aborting the print?

No it's protected by the double heat break. Afaik it never got warmer than 100°C in the stress tests Ultimaker performed before the UM3 launch.

Hilfreich bei der Auswahl ist wahrscheinlich das Angebot an frei erhältlichen Ersatzteilen, die ein Hersteller macht. Beim Ultimaker 2+ kann man sich das z.B. am Ultimaker 2+ Maintenance Kit orientieren.

Do you use the recommended settings or do you have some customization? If you want to make sure it is not heated, remove the PVA from printcore 2 with the assistent so the printer has "no material" in printcore 2. Then the second printcore should not be heated, not even during active leveling.

From some practical tests I can say that PP does not stick on PVA as @Tomhe wrote. So forget this combination for large horizontal overhangs or 'islands'. However, I managed to print a small object with PP and PVA support which had well connected PP layers and just needed the PVA as a bed so no PP line hangs on the bottom side.

In Cura 2.6.x gibt es ein kleines Durcheinander beim PVA. Du hast vermutlich 'PVA natural' ausgewählt und der Drucker hat 'PVA' geladen. Einfach ignorieren in diesem Fall. Du solltest bei der Meldung auch Details einblenden können, welche Dir darüber Aufschluss geben, was genau das Problem ist.

Na, ich lasse das den Kollegen @foehnsturm auf http://www.magnetic-tool-changer.com machen...

Achtung: Der UMO+ hat MXL-Riemen und die UM2-Familie GT2-Riemen. Das sind unterschiedliche Riemenprofile, die nicht gemischt werden sollten. Es gibt aber für den UMO+ ein Belt-Pack (UM-Artikelnummer 1561) das jeder gute Ultimaker Händler im Angebot hat und sicherlich jeder Distributor.

Meinst Du, dass über den UM3 viel Mist geschrieben wird oder dass Vieles am UM3 Mist ist? Hast Du ev. auch die Mark2-Erweiterung für Deinen UM2+ in Betracht gezogen?

As @labern pointed out, Diamond Age had very nice PLA filament. It now has a new owner who sells the filament under his brand, Imagin Plastics.

Colorfabb verwendet maschinelle Aufspulvorrichtungen, die man sich auch auf einigen Videos im Netz anschauen kann. Es ist recht unwahrscheinlich, dass dabei Verknotungen auftreten. Diese sind typischerweise das Ergebnis, wenn man eine recht volle Spule vom Drucker runternimmt und beim Ausfahren nicht gleichzeitig die Spule von Hand dreht. In selteneren Fällen kann ein längerer Rückzug (Retraction) auch schon dafür ausreichend sein.

Do you have firmware version 3.7.7 installed?

Please make your choice: https://www.google.com/search?q=wrench+5.5

Shell vs. infill: No; not yet. It's high up in the Cura priority list afaik.

The calibration data remains on factory reset; at least from fw 3.6.3 upwards.

Indeed Cura 2.6 needs more time to load and to switch profiles than 2.5. We are still far from where we were with 2.4 but it doesn't go in a nice direction.

Same problem here. Others have it as well.

Yes, HT is very nice for transparent prints. Just play around a bit with temperature and choose layer height and line width wisely.

Some of you may have submitted feature requests to Github/Ultimaker, most of them probably for Cura or the Curaengine. That's cool and exactly what's the idea of the repository there. But you should understand that you have to fight a bit for your ideas. Ultimaker seems to have implemented a procedure which downgrades feature requests on their priority list when there are no further comments for a request for more than three months. They had to do this because the number of feature requests is about five times the capacity they have. So, please do not just submit your ideas but make sure they are heard by the community. Share it here on the forum and get others to comment your idea on Github so Ultimaker sees that there is a common interest for the feature. Read other users' request and comment them if only with a +1 or -1. I'm confident this will also make life easier for the Ultimaker devs when they see what the most asked features from this community really are in addition to the information they get back from distribution.

@rhoogenboom: The problem with the USB you describe appeared with 3.6.2; 3.6.3 fixed it.

Which firmware are you guys running on your machines? If not yet 3.6.3, try upgrading it to the current version.

Upgrade the firmware to the current 3.6.3. It's anyway no fault to do this.

Are both boards genuine UM boards? If your machine is still under warranty, please contact your reseller.

TweakAtZ has been ported to Cura 2.x but it might well be it has problems with the Griffin flavor of the UM3. As the Cura devs think the current code base is not well structured I already suggested to implement the functionality into Cura itself and make TweakAtZ obsolete.