Fredl wrote: ↑
Sun Nov 12, 2017 6:02 am
Here's a pic of the entire printer:
That's kinda weird. I thought they shipped as direct drive printers. I guess modding it to a bowden would lighten the print head and help with ringing, though it introduces its own set of issues. Must be a grass-is-greener thing - people with bowden printers seem to envy those with a direct drive because of their ability to print flexibles.
Anyway... with that setup, you can definitely remove the fan and heatsink from the extruder motor up top. They are doing absolutely nothing for you. In the long run, it might be worth re-locating that fan back down to the hot-end, especially if you're printing PLA. But obviously, that's after you get it running.
The hot end is getting hot, the printer heats it to 190°C and all filament I have is PLA!
I'd try going hotter. Try 210 or 220. It's probably not going to solve the problem, but it might help.
I didn't check, since there's only a stub of filament left. Instead I tried to change the filament the way you explained it, but it is stuck. Even after squeezing open the gears, I tried to pull it out with force to the point where the filament broke. Now I'm left with ~1mm of filament to work with
If the nozzle is getting hot enough to melt the plastic, it means that either something is preventing the filament from coming out the nozzle (blockage), or from feeding it through the extruder. Unfortunately, that short stub of filament is going to complicate testing both.
I think your best bet would be to remove the bowden tube so you can troubleshoot more easily. It's actually not about removing the bowden per se (it's just a tube; it's not the problem), but disconnecting the filament from the extruder and giving you more filament to work with.
To release the tube from the brass fitting, you need to press the blue plastic ring down, towards the fitting, then pull out the white tube. Since you've got filament in the tube, you will also need to hold the lever on the extruder open, so it's not grabbing the filament. This will be a lot easier to do with two people.
If you can't release the tube (they can be a pain in the ass), you may need to unscrew the brass fitting.
Once the filament is completely free from the extruder, you can test the extruder to make sure it's working. Go into the menus on the printer and manually move the extruder - if it turns, it's fine.
You'll also have a longer length of filament to grab onto, so you can check the nozzle. Heat it up to print temperature, then try pushing a bit of filament through. Not a lot - a few mm should be enough - you just need to see if anything comes out the nozzle. If plastic comes out, then at least you know the filament is moving, so you should be able to pull it out of the printer now. If *nothing* comes out, you've probably got a serious blockage. For blockages, this is a really good video: https://www.youtube.com/watch?v=g8uvh6kvr54
Ok so why is the filament so heavily stuck?
Depends where the problem lies. If the extruder is broken, it may not be stuck at all; the motor just might not be pushing it forward. If the nozzle is clogged, it could be that the printer sat for too long, too hot, and cooked the filament inside. It could also be heat creep - you only want the rectangular block on the nozzle to heat up, the heatsink - the part with the cooling fins above it - has to stay cool. The fan on top of the extruder is probably designed to blow over the heatsink to help cool it (hence, moving it back down by the nozzle). So without it, the heatsink could have gradually warmed up, hot enough for the filament to melt inside, then get locked in place when it cooled down. Now, when you heat up the printer, you'd be heating up the heat block (as you're supposed to) but not the heatsink (again, as it's supposed to be), so the filament remains stuck.