Extruder clogged in a weird way
Good day. I left a print and went to bed last night only to find the printer printing in mid-air. Using gold silk PLA. Everything was going fine before I went to bed. I heated up the nozzle and tried to do a cold pull, but the filament broke right at the PTFE tube. How on earth do I go about unclogging the PTFE tube and by extension the heat break and nozzle?
RE: Extruder clogged in a weird way
Pretty simple, really. Heat the nozzle to 230c, then use tweezers to lift the end on the filament you see up out of the hot end. A bit tedious, but simple, and once there is enough normal filament showing, use needle nose pliers to help guide the end out the idler door.
When you get the piece of filament out, snap a photo of the stub and post it here. The stub can indicate where the jam occurred.
Also - you MUST keep the enclosure doors open when printing PLA. The printer must have an ambient (on LCD screen) below 40c or your extruder motor will be too hot for PLA.
RE: Extruder clogged in a weird way
I had that happen to me. For me it was copper silk PLA. The model had lots of retractions and the environment was unusually warm. I ended up Taking the nozzle off hot. And then taking the Extruder body apart to be able to disconnect the heat sink from the extruder body. At that point I could pull the filament and the PTFE tube out of the top of the heat sink. I ended up trashing the PTFE tube. Good thing that Prusa ships a spare.
My thoughts on the root cause. The Prusa specific heatbreak design has a step toward the hot end. 2.0mm dia toward the nozzle and 2.2 elsewhere. I changed that part out for a standard E3D heatbreak with no step and haven't had the problem since. Once you get it apart if there is a section of melted filament that' is 2.2 mm diameter above a section that is 2.0 that was in the hot end of the heat break then that is the problem I had.
There are some who attribute this issue to the extruder stepper getting too hot and melting the filament in the bond tech gears. Personally I think that is a secondary issue if it is an issue at all.
Good luck.
Paul
RE: Extruder clogged in a weird way
I am still confused. How exactly do I get it out. Do I have to remove the heatsink/hot end assembly first?
RE: Extruder clogged in a weird way
Filament broke right at the surface of the PTFE tube. 😔
What can I do now?
RE: Extruder clogged in a weird way
You can heat and try pushing the filament down with a metal rod (an allen wrench has worked for some). When it is far enough along new filament will work.
Or, remove the hot end. Once it is out of the extruder you can unscrew the heat sink from the heat break and gain access to the PTFE, and any filament in the heat break.
But you haven't answered the simple questions about printer environment: enclosure, room temp, etc. That really would be helpful to know.
RE: Extruder clogged in a weird way
I live in the tropics. Room temperature is always about 25C and the enclosure is about 42C. Nozzle temp at the time was 210C.
I built this kit from scratch, yet it is daunting to fix this issue.
The filament is right at the PTFE tube just bearly over the tip of the PTFE. What temp is ideal to heat at? Should I push hard?
Also, how do I clean the bondtech gears?
RE: Extruder clogged in a weird way
Someone answer the above please.