UM3 crashes into bed after first layer

[Shaggy 0]

Hi guys,

I have a very strange issue. When printing a part with only one nozzle. After some time the UM3 automatically cleans the unused nozzle. That's okay typically this happens after layer 20 or whatever. But when I print a part with a very big initial area the cleanup process starts at the second layer.

Then the head moves back to change the nozzles and crashes/scratches the plate, in addition it gets stuck to the backward holding clips. After a lot of rattling it gets back working but already missed some steps because of the stucks and the second layer differs in position to the first layer.( 2-3 cm)

I leveled the bed manually and in auto mode etc. nothing helps. Slicer is the newest Cura also reseted the UM3. A print right after that with a smaller initial area prints just fine, because the Z axis is high enough after some layers. And the unused nozzle clean works just fine.

Any ideas on that? Seems like a bug, when the first layer is big enough so the nozzle clean procedure needs to start right after that.

Firmware is 3.7.7 ( newest at the moment)

Thanks in advance

Shaggy

Edited August 12, 2017 by Guest

[Dim3nsioneer 557]

I'm not sure if I get your issue correctly as there is no nozzle cleaning but a level switching on the second printcore.

If this is your problem, i.e. the print head does not drive to the level switch correctly, you might want to try to re-calibrate it. There is an assistant for this in System->Maintenance->Calibration (first option) on the printer.

In case I got you wrong, please post a short video.

It might also be a good idea to get in touch with your Ultimaker reseller as driving into the clips is far from standard behavior and hints for an issue which might fall under waranty.

Edited August 12, 2017 by Guest

[Shaggy 0]

Thanks for the answer. I will prepare a video.

Okay maybe cleaning is wrong. When a print starts it squeezes some filament out at the corner (a small blob) with the filament you want to print. Then after the first or some more layers (depending on first layer area) it does the same with the unused nozzle/filament. And when this happens at the second layer it crashes.

[Dim3nsioneer 557]

This might happen if your z calibration is far off. Go to System->Maintenance->Calibration-> Calibrate z and give the machine a reasonable height for the second printcore.

[tomnagel 126]

Squeezing out filament in the blob is called priming.

This sounds like a bug to me.

You write that you want to print with only one nozzle. I think you can circumvent the problem if you only use the left nozzle, and making sure that all functions like brim and support (even if support is turned off) are set to print with nozzle 1.

Nozzle 2 is then not primed