Hotend jams on every print, no idea why
The Problem: I cannot figure out why my printer keeps jamming. Every print I will get a perfect first layer, it will print perfectly until the extruder gears dig grooves into the filament and just start clicking. This happens anywhere between 20 minutes in and several hours, but usually within 40 minutes.
What I have: I have a MK3s-MMU2s extruder assembly, but the MMU2s has been removed due to it never working properly. I planned on working to get that reliable once I can get the printer to actually print. I have a MK3s+ extruder upgrade on order, along with all new hotted hardware and if nothing else maybe that will fix my problems.
What I've tried:
- Used new filament, including prusament. Also used multiple filament types (PETG, PLA)
- Changed to a new nozzle
- Changed to a .8mm nozzle. This worked, but I don't want to print with a .8mm nozzle all the time, I prefer .4mm.
- Slowed the print way down. This usually makes it take longer to jam, but it kinda sucks to have to print things at half speed to get them to work
- Replaced the PTFE tube in the extruder. I heard those wear out over time.
- Tried higher and lower temperatures
- Tried tightening the spring loaded extruder screw to extreme loose, extreme tight and everything in between.
- Im sure many other things, I can't remember them all since I've been at this for months now.
Every time it jams I pull it out, snip it just before the grooves, load it and it loads fine. Attached is what the filament looks like pre-snip. 
Thanks in advance for any help!!
RE: Hotend jams on every print, no idea why
Are you using Prusa Slicer
Is your printer in an enclosure, or a high ambient temperature?
Are you using more than 0.8mm retraction?
what extrusion multiplier are you using
can you attach a .3mf for a project which always fails?
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend jams on every print, no idea why
@joantabb
It says the 3mf file type is not permitted for security reasons?
Anyway I am using the default retraction, which is 1.4mm. Do you think reducing that will help?
Not in an enclosure, I am trying to finish the prints to create my enclosure.
My extrusion multiplier is 1.
Thanks again for your help
RE: Hotend jams on every print, no idea why
@joantabb
To clarify, I am using all default settings for generic PETG, on the default settings for my mk3s. Only setting I changed for this one was to reduce retraction from 1.4mm to .8mm, and it failed same as all the others. The file is the 60 degree hotbed cable mount for the mmu2s enclosure.
RE: Hotend jams on every print, no idea why
you need to zip compress .3mf files so that they can be attached!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend jams on every print, no idea why
@joantabb
Oh gotcha. Here you go!
RE: Hotend jams on every print, no idea why
Hi Travis,
I have just done some 12 hour plus PETG Prints and pretty much the only differences are,
I used Gyroid infill at 30% (it's a model for outdoors and I would like it to be vandal resistant
I used 4 perimeters at 0.6mm extrusion width, (this shouldn't make a difference to your print)
I used 0.95 extrusion multiplier and
I used 0.4mm retraction
Is there a reason why you used 0% infill?
Could you try re printing with extrusion multiplier .95 and retractions 0.4mm and see if it makes a difference for you?
Regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Hotend jams on every print, no idea why
I did encounter the same problem when I fresh build a clone MK3s several months ago. It is a Chinese clone kit. the Problem is located at the heat block
1. be sure you have a little gap between nozzle and heat block
2. make sure applying thermal grease on the throat when attach to the heatsink.
3. make sure the PTFE tube is pressed all the way down to the bottom of heatsink and locked properly
This work for me on PETG filaments, but for PLA my extruder temperature is too high(50degrees) that melt the PLA at the gear position...