i3 MK3S+ looks like it's jamming mid-print  

RE: i3 MK3S+ looks like it's jamming mid-print

It does indeed look like a clog.  However as you indicate it could be the Bontech gears loosing grip.  Have you checked the tension on the gears?  Too much grip is just as bad as too little.  I find that setting the tension as recommended in the assembly manual works just fine.

As for unclogging the extruder, how have you done that?  Have you tried changing out the nozzle?  I had a nozzle clog due to a tiny piece of metal that was in the filament, normal cleaning methods didn't work for me, I had to replace the nozzle.

Cheers

-Bob

RE: i3 MK3S+ looks like it's jamming mid-print

I think the tension on the gears was off. Set it according to the assembly manual and I'm not getting PLA dust in the extruder the same way I was before. It's a bit surprising because I haven't adjusted the tension in well over a year and it hadn't been a problem until now.

For unclogging the extruder, I've done a hot pull, cold pull, unclogged with the needle tool that came with the printer, and pushed an appropriately sized hex key as far down into the extruder as I could (it bottomed out) and some filament came out, but I have a proper unclogging tool on the way to see if there's anything else that needs to get pushed out.

What has happened to that print sheet?  It looks terrible.

There are signs that the belt tension(s) might need adjusting but that wouldn't cause your immediate problem.

Please save your project as a .3mf file

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

Cheerio,

RE: i3 MK3S+ looks like it's jamming mid-print

Posted by: @diem

What has happened to that print sheet?  It looks terrible.

There are signs that the belt tension(s) might need adjusting but that wouldn't cause your immediate problem.

Please save your project as a .3mf file

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

Cheerio,

To me it looks like its been sand papered down, yes indeed people do that, why, i have no idea.

RE: i3 MK3S+ looks like it's jamming mid-print

Here's the zipped .3mf file:

jam diagnosis

As Hello suggested, the print sheet has been sanded down. These are classroom printers that get used by large groups of 15-17 year old students and I've found the simplest way to guarantee good adhesion to the build plate is to occasionally wipe the surface with rubbing alcohol then to gently sand the surface (and clean it) if there are still issues.

Thanks for offering to help with diagnosing the problem and for suggesting I look into the belt tension(s)!

Oops, I should have been clearer:  Load your file, setup the print and slice as you would for printing; then save the project, it will carry the settings you use along with the part.

BUT:

Your part has over a thousand file format errors - notice the warning triangle next to the part name in the right hand pane - it is never going to print as you expect ... and it doesn't look much like the failed print pictured above..?

What CAD software are you using?  I suspect a preference setting has been set to output for videogame or movie assets and not 3D printing.

* * *

Print this:   https://www.prusaprinters.org/prints/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus

It MUST be printed in Prusament PETG or the spring tension will be wrong.

Also, I suspect your filament is damp which isn't helping.

I've found the simplest way to guarantee good adhesion to the build plate is to occasionally wipe the surface with rubbing alcohol then to gently sand the surface

Oh dear, the simplest way to guarantee good adhesion is to keep the build sheet scrupulously clean, wipe with alcohol between every print and use diswashing detergent (Dawn/Fairy) and HOT water at the first sign of problems.

These are classroom printers that get used by large groups of 15-17 year old students

And I've found the best way to get kids to respect the machines is to supply cheap plastic gloves (fuel station type) and insist they are used when handling the build sheets.  Yes, that is way over the top but it keeps the stickier substances off the machine, gives them a trophy of their responsibe use (to use irresponsibly) and makes them look on the machines as special.

Cheerio,

RE:

Oh dear, the simplest way to guarantee good adhesion is to keep the build sheet scrupulously clean, wipe with alcohol between every print and use diswashing detergent (Dawn/Fairy) and HOT water at the first sign of problems.

To add to what I originally said: I took a leave last year and came back to build plates completely covered in glue with dents and other signs of misuse. Cleaned it all off with alcohol then let the build plates soak in hot, soapy water and cleaned them off with alcohol again and there were still issues with adhesion. Sandpaper was a last resort. It's not pretty but it's been working. You're right that I should have students cleaning the build plate with alcohol before every print and will add that to required procedures for printing.

What CAD software are you using?  I suspect a preference setting has been set to output for videogame or movie assets and not 3D printing.

We're using TinkerCAD and Ultimaker Cura is our slicer. TinkerCAD because (1) students with Chromebooks can still use it (2) it's free and (3) we can also use it to breadboard circuits (this is a Robotics & Design class). It streamlines things nicely and 4/5 printers have yet to have any issues. Ultimaker Cura instead of Prusa Slicer because it gives students clear, visual feedback saying whether their model is likely to print successfully or if the print is likely to fail which is invaluable.

I assumed PrusaSlicer as you are posting here - and I was expecting a .3MF from PS; I'm out of date with Cura - but it too will have problems slicing this part.

To have a decent chance of diagnosing your failing print(s) we need to eliminate upstream issues - if you can source and slice a correctly formed mesh file, print it and show us any remaining issues we may still be able to help.

Cheerio,