Troubleshooting advice needed for interesting print issue

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Troubleshooting advice needed for interesting print issue

Post by Polaris » Sat Feb 15, 2014 7:54 pm

Hi fellow 3DPer's

My current setup has been in operation over a year now without issue until now

The feeder stepper motor (FSM) on my Up1 printer is having hiccups... it's backing and forthing like a DJ's Jazzy's turntable track.

In the vids, take a close look at the stepper motor jagging back and forth - kinda hard to see but that clunk sound you hear is the stepper reversing momentarily suddenly then rotating forward again.

The times the FSM would normally reverse would be at the end of a pass in which it stops the thread from being over-extruded.
And usually does so quietly, not this rapid change in rotation direction.

Now the interesting part... is the action is semi consistent.
these two vids to show the difference &
and a photo or two
This one printed ok until last third or so
VIRB0_Print_Issue01-25%.jpg (137.64 KiB) Viewed 4211 times
regular pattern of forward/reverse feed leaving gaps
VIRB0_Print_Issue02-25%.jpg (104.83 KiB) Viewed 4211 times
Problem occurs...
during extrusion : some times
during raft building : yes, the first layer down run especially
during print : halfway through usually tho some times not at all, and some times in the first half and sometimes in the second half.
..seems to mess up an entire layer (or series of layers) with a dash-dot-dash-dot-dash pattern, but not partial layers.

Things I thought it could be : nothing comes to mind... not a single thought even.
I've Changed the filament and cleaned the whole head including nozzle and heating block thoroughly.
Checked the USB cable, tho there's no issue communicating with the UP - all requests (pause, etc.) are fairly instant.

It seems it may be electronic or perhaps data related (some models print fine 1st time, then fail next time around ).
The stepper is still in very good condition and never gets hot.
If the stepper failed I would expect a degradation type failure, rather than an intermittent failure like this issue (perhaps I'm wrong here, but due to my stepper having a modified shaft I cant swap it over to check).

My printing has been ongoing for the last 2 years and this is the first time this particular issue has come up.

Any idea's welcome... Cheers Matt
|=Polaris D+sign =||= designing the bleeding obvious since 2005 =|

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Re: Troubleshooting advice needed for interesting print issu

Post by wackojacko » Sat Feb 15, 2014 11:26 pm

Hi Matt

My 5c would be the rainbow ribbon cable from the motherboard to the head has a small break in it.
Or the stepper is on it's way out.

Need help with your printer, check out our Youtube channel. ... /playlists

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Re: Troubleshooting advice needed for interesting print issu

Post by roller » Sun Feb 16, 2014 2:57 am

I couldn't see your issue ... I hear the clunking of the extruder missing steps (you might see a slight twitch backward) which is simply caused by the nozzle jamming (normal on first layer when the bed is too close and the backpressure causes the nozzle to skip). I saw not other abnormal clunking or weird behaviour though blurry photos and low res videos do nothing to help understand your issue. You should see the stepper motor step backwards in normal printing ... this is a retract and the extruder will do it whenever it is doing a rapid so the extruder doesn't ooze during the move.

If you still are sure you have an issue please post a video that is clear and higher res (youtube compression doesn't help much with such fine detail at 480p)

Also, if you are generally having problem with adhesion and your bed is as level as you can get it chek the forums for solutions such as using elmers glue, abs paste etc. If it's just an occasional issue (with an especially troublesome print) I use a blow torch style lighter to melt the rogue filament that has pulled up so it sits flat on the bed to stop the extruder catching on it next time.

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