Aaah. Both my printers are now out of action.

(Gordon Broom) #1

Aaah. Both my printers are now out of action. Still trying to get the TwoUp to actually extrude. I’ve replaced the wooden extruder body with a printed one (and fastened it to the printed X traveller), got the fan going, but I can’t get any plastic going through other than by hand. Also got homing switches installed so I have repeatable positioning. But now the pulley on my Cupcake’s X axis is slipping so I’m unable to print any more parts. Tried tightening it in situ, but that didn’t work. Have to pop it out.

And I guess I will have to disassemble the TwoUp extruder and see what happened inside. Sigh. It was such a pain to assemble to begin with, because everything has to be put together all at once.
I think I have an old MakerBot gear that I can put on the extruder stepper to give it a bit more grip. Now that the fan is working I don’t think it’s heat creep up into the guide tube, I’m hoping it’s stepper related, or maybe the filament just not lining up after the gear.

(D Rob) #2

maybe a partial clog try a warm pull. is the filament stripping/grinding or is the motor stalling? Is there a ptfe tube in the peek insulator? if so is it cut square? is it fully seated? Try extruding without retraction after a warm pull.if that works, but not with retraction tweak the firmware on acceleration and jerk and retraction speed and distance. without the hotend attached does extrude 10mm give you 10mm(use calipers)? Check filament diameter, several points and at each point check around the radius as it is probably ovoid. just want to make sure at no point is it too wide in any angle,and that you are not trying to over extrude which can also be a jam cause

(Gordon Broom) #3

Unfortunately I’m out of town this week so I won’t be able to try anything until the weekend. I thought the filament was not being gripped enough so I cranked in the tension on the idler spring. That didn’t help.

With the original wooden extruder I ended up with heat creep, the filament just started folding over itself below the gear. I can’t see what’s going on in this printed extruder, so I will need to pull it apart. I do have a fan now, keeping the feed tube cool.

I have not got to the point of calibrating the flow (10cm requested == 10cm delivered), since I can’t get any going through at all. It is on my list to do (as well as convert to volumetric measurements).

(D Rob) #4

feed calibration needs to be done without a hotend attached.10mm =10mm extruded at full diameter. not extruded. this may be your issue. proper e steps

(Gordon Broom) #5

I think the problem was I didn’t get the filament pushed all the way into the heatbreak, so the gear ended up either stripping it or bending it. I tried again with a really straight end and managed to feel it slide into the heatbreak. I can now extrude.