Print blockage issues
I had what seemed like a partial blockage. Filament was not extruding and there was a clicking noise. I was due to upgrade to the mk3s so I did this. I preheated and fed filament through without a problem. I ran z live and immediately the same problem occurred. I did a cold pull but am having the same problem.
Has anyone else had a similar experience where the filament flows no problem when loading but hardly comes out when printing? If so did you diagnose the problem. What was your solution?
thanks Alan
RE: Print blockage issues
Maybe check that your idler tension is proper, if it is then take a look at the bondtech gears make sure that the one attached to the stepper motor is not slipping and check that the other is still seated in the hole for its axle.
that's all I can think of
The Filament Whisperer
RE: Print blockage issues
Having just had this problem I suggest checking that the grub screw on the extruder gear is tight.
RE: Print blockage issues
Today I developed the same problem, after a day of doing decent prints on and off with no problems.
If I autoload filament, it does so, at the appropriate temperature, and pulls it in strongly, squirting it out at the nozzle enthusiastically. If I answer "no" to the question about the right colour coming through, then the gears do their bit again and a whole load more filament is extruded silently, with no clicking or problems.
If I ask it to unload the filament, then it does so correctly, ejecting it back out with no problem. The gears are doing exactly what they should.
But every time I give it something to print, or ask for a first layer test, then the gears click briefly, and nothing whatsoever comes out after the 9 point test. Not even on the bit where it usually prints a line outside the print area. Nothing.
I can go back to the previous two states with no problem, and everything is as it should be with the gears and hotend and nozzle performing as they ought, but I can't get any actual printing to happen.
This is most frustrating, and I am really unsure where to look - this seems to be a logic error, as the gears etc. function normally as long as I'm not printing. The gears are clean and correctly positioned, the grub screw on the extruder flap is adjusted as it has been since I had the machine, and has not changed - the tip of the screw is just proud of the surface of the flap.
I've done a factory reset, which sadly has changed nothing.
Again, after 3 months of printing with no problems (except for a failed X stepper motor, which Prusa replaced very rapidly indeed, I wonder if this is someting I have caused: Yesterday, I downloaded CURA, et it up for a Prusa i3 Mk3, and use it a couple of times to compare how the printer performs with both. Could this have screwed something up? Actually the Cura prints worked well today, and produced good results from the SLT file, although slower than the Prusa Slicer got from the same file.
If it were the Cura gcode causing the problem, then I would expect a factory reset to sort things out nicely, but it hasn't.
So my gears and extruder perform fine during filament loading and unloading, but as soon as I ask the machine to print a file, there is a short period of clicking when printing should start, and then silence with no extrusion at all, and no evident attempt to push filament through the hotend. I am stumped by this one.
Some advice if anyone has any ideas would be very gratefully received.
Cheers,
Pad
RE: Print blockage issues
Just to be clear, the the screw or screw's that go through the flap on the extruder are the ideler screws, they provide tension to the filament.
The grub screw as its being referred to, is a small Allen screw that goes through the Bondtech gear that rides on the stepper motor that drives the filament, if its loose one of the first signs can be inconsistent extrusion. how it might act can depend on the speed and torque the stepper motor is applying at a given time, vs how loose the screw might have become. checking that screw is snug and sitting on the flat part of the stepper arbor is a good first step when experiencing the symptoms your describing.
Hopefully that's all it is since its an easy fix, if not move on from there.
Regards
Dan
The Filament Whisperer
RE: Print blockage issues
Thanks for the clarification, @dan-p12; I was using the wrong words for the wrong parts.
But I had checked the idler screw, which I described before and it was in the usual position.
I checked the grub screw, and it was quite as tight as I made it when I put the kit together, which was both disappointing and affirming!
I heated the hotend up to 250 and poked about for some time with a 0.14 steel wire, getting out some surprisingly solid junk from the nozzle. I thought that'd fix it, but it didn't.
I then replaced the nozzle, following which it worked (and has done all afternoon) fine.
I'm chuffed that it's working, but I'm not sure why replacement of the nozzle sorted it out. Perhaps there was some residual junk left inside which softens, and is pushed by the flow of melted filament into the orofice, blocking the flow.
I can't think of a good way of cleaning the inside of the nozzle except for a cold pull, which I don't fancy trying with PLA, as it is quite prone to breakage.
Is PETG OK for the cold pulls, or should it just be nylon?
But I'm back in business, so I'm a lot happier.
Pad
RE: Print blockage issues
I'm not surprised about the blockage, the one and only time I had a blocked nozzle it seemed like a mystery to me how it became blocked, just like yourself I changed it out and things where flowing great again. since that time I started doing cold pulls as general maintenance, and to date I've not had another block. you can buy a length of nylon filament on amazon and several other places and just keep it around for doing pulls. I'd stay away from using PETG or ABS for pulls. I bought the eSUN printer cleaning filament, It doesn't say what it is but it looks like nylon to me, it was about $12 US and I think it was about 100 feet\30 meters
The Filament Whisperer
RE: Print blockage issues
No sooner said than done - I've ordered a part-roll of nylon filament which should do the job nicley.
Pad
RE: Print blockage issues
[...] I bought the eSUN printer cleaning filament, It doesn't say what it is but it looks like nylon to me, it was about $12 US and I think it was about 100 feet\30 meters
I'm also a fan of the eSun cleaning filament. My favorite was rigid.ink's, but they've ceased production.
I don't think it's nylon because it will also melt out at lower PLA temps, which is ideal for cleaning filament. If any gets left behind in the nozzle, it will melt out the next time I print. With higher-temp nylons, any residual filament left behind in a cold pull can itself cause a partial blockage.
I also don't worry about cleaning filament absorbing moisture. A bit of "foaming action" is beneficial for cleaning. The rigid.ink cleaning filament was fantastic for this and would really expand as it extruded.