Ultimaker stop dual nozzle development

So, Ultimaker & by extension, Cura, have [color=#0000FF]announced[/color] they have abandoned development of a dual nozzle solution for their UM2. Their software engineer [color=#0000FF]gives their reasons[/color]:

[quote]Don’t get me wrong. The other problems are also present. Oozing from the inactive nozzle will make your print look ugly. Printing with PVA clogs the nozzles. Calibrating the height of both nozzles exactly right is hard… But your failure rate on single extrusion prints goes up to 30-50% or something. Not just tall easy to knock over objects. Also large flat things can fail.[/quote]I’ve not had any of those problems and I’ve been printing with two nozzles since the beginning of the year! Not saying that printing with two nozzles is easy - it’s definitely not and you have to have the right model to print, but it’s surely not as bad as they make out?

Does this also mean that printing support with PVA is now also dead in the water? Seems such a shame.

I guess this means the support for dual nozzles in Cura is now frozen?

Same here. I could print with dual nozzle without too much hassle.

Velleman confirmed that PVA is clogging the nozzle. I was expecting using PVA. I’ll try using PLA as support but I don’t have an ultrasonic bath.

Let’s hope not.

During development of the Vertex I also encountered these problems… They are inherent of the dual nozzle FDM process in my opinion and I tried to mitigate them where I could. I think I reached a comfortable compromise between being able to print with dual heads without making it to hard to use or causing every print to fail. We didn’t think a single nozzle with two materials was the way to go as it limits the materials you can use side by side and it also makes the hotend way to complicated.

Regarding the PVA problem, we are working with our filament supplier to make a PVA filament that doesn’t carbonize as much but it is still a very real problem at the moment. Printing with hips and PLA (or ABS) works perfectly but it requires Limonene to dissolve the HIPS. It smells a bit funny though… Dissolving PLA also works but that is a nasty process, but it works. I completed several prints with support material that needed to be dissolved.

[quote=“VEL327”]During development of the Vertex I also encountered these problems… They are inherent of the dual nozzle FDM process in my opinion and I tried to mitigate them where I could. I think I reached a comfortable compromise between being able to print with dual heads without making it to hard to use or causing every print to fail. We didn’t think a single nozzle with two materials was the way to go as it limits the materials you can use side by side and it also makes the hotend way to complicated.[/quote]I think you’ve done an excellent job. However, I guess to some extent it relied on having support for dual nozzles in the slicer. I hope that will continue with Cura.

[quote=“VEL327”]Regarding the PVA problem, we are working with our filament supplier to make a PVA filament that doesn’t carbonize as much but it is still a very real problem at the moment. Printing with hips and PLA (or ABS) works perfectly but it requires Limonene to dissolve the HIPS. It smells a bit funny though… Dissolving PLA also works but that is a nasty process, but it works. I completed several prints with support material that needed to be dissolved.[/quote]Can’t the carbonisation be mitigated to some degree by using a long enough retraction? I know some residue always remains, but would that be enough to clog the nozzle? What about a very low temperature PVA type of support filament?