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print failure - any guess?

Posted: Sun Jun 02, 2013 3:45 pm
by uwes
hi,

i was attempting to print http://www.thingiverse.com/thing:67071. I've used slic3r0.99+RepetierMax Firmware+RepetierHost and apparently the print is showing good quality initially.

in total this are ~210 layers. i got ~180 correct layers and then something happened. process parameters (temp, speed) have not changed manually, filament did move "normally",...
20130602_200106.jpg
also the layers do not stick together (as if it would be too cold)
20130602_200247.jpg
in addition i noticed the following:

1. after ~200 layers of 210 stopped and homed all axes, switched off bed+extruder pretending to be finished (current height is 61.65)
2. with a kiss slicer .gcode i saw "printing layer 310 of 300" (basiclly more layers than in the file)

- does this look like a mechanical/extruder/etc problem or a slicer/firmware/host issue?
- are these known issues?

/uwe

Re: print failure - any guess?

Posted: Sun Jun 02, 2013 4:02 pm
by foshon
The de-lam could be temp related, but since the print gave up the ghost all together at that point I think you may have slipped a belt. In my opinion, it looks like z missed a step and you started printing into the air. Not much .5mm or so, one tooth? You went from great layers to nothing sticking in one layer... odd.

Re: print failure - any guess?

Posted: Sun Jun 02, 2013 4:45 pm
by Broose
Could be an extruder issue that developed causing filament starvation. Its unlikely that you could skip along the Z axis on a Rostock without also shifting X or Y because all three motors would have to loose steps.

Re: print failure - any guess?

Posted: Sun Jun 02, 2013 5:57 pm
by foshon
Broose wrote:Could be an extruder issue that developed causing filament starvation. Its unlikely that you could skip along the Z axis on a Rostock without also shifting X or Y because all three motors would have to loose steps.

I agree, but the very definitive layer height the issue starts causes me concern.

Re: print failure - any guess?

Posted: Mon Jun 03, 2013 12:07 pm
by JohnStack
I've had that happen a couple of times but never twice in a row - because I kill the software and recycle the printer between prints.

You may also want to try running that STL through a fixer like Meshlab.

Re: print failure - any guess?

Posted: Mon Jun 03, 2013 3:08 pm
by Eaglezsoar
JohnStack wrote:I've had that happen a couple of times but never twice in a row - because I kill the software and recycle the printer between prints.

You may also want to try running that STL through a fixer like Meshlab.
Do you like Meshlab better than Netfabb to repair STL files?

Re: print failure - any guess?

Posted: Mon Jun 03, 2013 3:17 pm
by dbarrans
Recycle the printer? That's a bit drastic, don't you think? :-)

Does that go in the paper, plastic, metal, or glass bin?

- dan

Re: print failure - any guess?

Posted: Mon Jun 03, 2013 4:06 pm
by JohnStack
Haven't used NetFabb.

Looks feature rich!

Recycling, yeah, old term I guess. My first computer project was done with punch cards if that tells you anything.....

Re: print failure - any guess?

Posted: Mon Jun 03, 2013 6:40 pm
by uwes
hi,

i did restart the rostock as normal today after yesterdays failure. But extruding material did not yield a reliable/good flow at all. Before when extruding into the air it was a consistent flow but now it was just thin curling material. After disassembling the hotend i've found that the inner ptfe tube did shrink in the 5mm section inside of the nozzle. the inner diameter is now ~1.7mm (instead of 2mm before). Inside that section of reduced diameter i've found a stuck piece of ABS where only the outer shell remained forming kind of an internal nozzle. i assume this in total reduced the flow almost to a full starvation. I'll clean the rest of the hotend and then we'll see.

regards
/uwe