Dual Extrusion Support - Nozzle hits the print

Discussions about firmware/slicing software, tweaks and settings
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Joined: Fri Mar 21, 2014 7:27 am

Dual Extrusion Support - Nozzle hits the print

Post by hanscl »

Hello All,

I've had my Felix Printer 2.0 for a couple of months now and I love it. These past couple days however I have gotten stuck trying to print support using the 2nd extruder.

I use the registered version of kisslicer and select "Ultra" support. I double checked the calibration of the bed and the hotends of both extruders. I also just did a print with a raft using the 2nd extruder and it worked fine.

In this current print, the nozzle (tip) of the hotends hits the print when it comes back from the home position to print the support. I believe the problem is that it prints three regular layers with hotend 1 (which in normal quality is 0.6mm), so when it adjusts the print head for the support layer the tip of the hotends are probably 0.2mm-0.4mm above the print bed (or the last support layer). This of course is lower than the last regular printed layer and the nozzles will "scratch" over that last layer, which damages the print and probably won't be great for the extruders in the long run. :?

During the last print I tried increasing the z-distance a little bit, but while the hot ends were still hitting the print, the layers wouldn't stick anymore (which I did expect unfortunately).

I think the solution would simply be to print one regular layer and one support layer right after another, rather than multiple layers with each extruder before switching. Needless to say this will increase the print time as the head will move to the home position much more frequently, but it should work.

My problem is that I couldn't find any setting in kisslicer that would achieve what I am thinking.

Has anybody here dealt with the same problem? Any suggestions for Kisslicer settings that will work for dual-extrusion support would be much appreciated. Or is there another software that supports dual extruders at this time?

Thanks so much,

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Joined: Sun Jan 04, 2015 12:45 pm

Post by neep »

I have the same problem with my brand new DIY Felix 3.0 + dual extruder upgrade. The second extruder is very close to the first one, so when for example printing lots of round objects (chess pieces right now, for example) I find that the second extruder nozzle keeps hitting the print even if it isn't used. I raised the second extruder by accident the other day by crashing into a print on homing. It's not 0.5mm higher than the first extruder. However, it is /still/ hitting the prints.

I find the second extruder to be totally useless like this and I'm considering removing it altogether. A shame I wasted €129.50 on it. Removing it will also get better inertia characteristics for the total print head. I was hoping to be able to do PVA supports with the second extruder, but if it keeps hitting the print then it's useless.

My ideal FFF printer would have retractable extruders that are pulled completely out of the way when not being used. Like the old "multi color" pens, if anyone remembers those.

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Joined: Fri Dec 05, 2014 11:14 pm
Location: Luxembourg

Post by fesch »

I pulled down the first extrude a little bit, so the problem is solved. Printing with two extruders is very slow anyway, although it depends a lot on the slicer's strategy.

The idea of retractable extruders is great, but that would mean that each extruder would need another motor to make it move?

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Joined: Thu Nov 27, 2014 4:45 pm
Location: California, USA

Post by jjlink »

I had the same issue with the second extruder nozzle keeps hitting the print. So I temporary removed the second hot-end.

Also keeping the two extruder hot-ends aligned to the same point at the peak needs some better solution as well.
Felix 3.0 with E3D Dual direct drive extruder conversion. (http://forum.felixprinters.com/viewtopic.php?f=9&t=1630)
Software: simplify3d

Posts: 19
Joined: Sun Jan 04, 2015 12:45 pm

Post by neep »

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