Random parts missing from Print  

RE: Random parts missing from Print

Posted by: @cncrc

HI 

 

I have had my I3 Mk3 for 2.5 years now and it has been great up until the last few days.

It calibrates fine reports no issues on self test etc however it randomly appears to stop extruding.

There is no clicking of the extruder and no damage to the filament.

I'am quite stuck on this have checked the bondtech are aligned free form debris etc 

This can happen 1st layer or 3 hours into a print.

The room conditions are the same as they have been for 2.5 years I also have a Mini and have swapped the fillament form the I3 to the Mini to rule out the filament. 12 hour print with same filament no problems on the mini. Have also tried different filaments cold pull changed nozzle etc.

Hoping someone can point me in the right direction

Many thanks

Mark

At first view, this seems to be a first-layer problem. I would first look for the cause (closer to the print bed).

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/

RE: Random parts missing from Print

@karl-herbert

Thanks for the recommendation however I have several examples now as stated in my original post that the first layer is fine and the issues occur much later in the print.

I have attached some photos.

Regards

Mark

RE: Random parts missing from Print

@cncrc

Ok. This looks like a partially clogged hotend or extruder problem. have you worked through the tips on this Prusa page?
If the hotend and nozzle are ok, I would look at the short PTFE piece in the hotend and replace it if necessary. Possibly the extruder drive gear is dirty or the screw to fix the gear is not tight.

RE: Random parts missing from Print

my vote goes towards nozzle replacement, sounds like a clog.

RE: Random parts missing from Print

Check the srews on the extruder pulley, if not loose. Because when nozzle is cloged, it usually cause the clicking sound of extruder gears. But if you can not hear anything, it might be because it just not turn at all.

RE: Random parts missing from Print

Do a few cold pulls, look on prusa website for the manual on how to do this. PLA and with low temperature....

RE: Random parts missing from Print

Hi All

Ok gone through so many different things here doe 3 cold  pulls new nozell new PTFE liner renewed the thermal paste on the heat break stripped down the bondtech gears checked them over they are fine.

Is it possible that here is a intermittent cable break in the extrude cable.

Printer has done 300 days of printing in total.

I have checked the cables as best I can with a multi meter can not detect a brake when flexing them but that is not always a conclusive test due to angle of movement heat etc when printing.

Thinking that all there is to try now is cable replacement.

Does anyone have any idea on the print time on average before failure ?

Kind regards

Mark 

RE: Random parts missing from Print

@cncrc

Try calibrating the extruder. This should uncover any irregularities in the extrusion:

https://all3dp.com/2/extruder-calibration-6-easy-steps-2/

Are the esteps/mm set correctly for the Bondtech?