QU-BD jamming

Hey guys, pretty new to 3D printing, I am converting my zentoolworks 12x12 into a 3D printer, then using it to build a TAZ so I can still use the mill
I bought the QU-BD dual head print head not realizing how many problems they have. I read up and made a couple upgrades right off the bat with my makibox. I added a MK7 gear and made the spring tensioner with a ball bearing.
The problem I am running into it this.
Using Repetier host I turn on the fan and the hot end, I feed in the 1.75mm filament and it pushes thru fairly easily.. extrudes out the bottom just fine. I then click on the extrude button in the manual manual and it pushes out some plastic. The problem comes in when I let it sit for like 10-20 seconds, it then will not extrude any more, I cant even push the lever to release the preasure on the filament and manually push the filament thru. I pull the filament out and the end of it is buldged out about 3mm up (as per the image uploaded)

So, is this the barrel on the hot end getting hot to high? I thought thats what it was, so I took it apart, added some artic silver to the heatsink between it and the black mounting block, and that seemed to give it a little more time (not sure tho)

Any help would be appreciated I wanna get printing! (my makibox died right after printing the upgrade parts for the qu-bd)

I too am getting the exact same issue. I have the QU-BD extruder on my Ord Bot printer. Trying to print ABS black at 230 degrees C. the nozzel is .5 diameter.

Shreddin, how long does it usually take for your hotend to heat up? what do you mean by this: made the spring tensioner with a ball bearing.? attached is the gear that i am using. is this the same as the MK7 gear? it seems like the gear I have does not have enough tension to even pull the 1.75 filament down

Any advice from the forum Pros gladly appreciated. Should i just buy a different extruder?


Janski

Quote
Janski
I too am getting the exact same issue. I have the QU-BD extruder on my Ord Bot printer. Trying to print ABS black at 230 degrees C. the nozzel is .5 diameter.

Shreddin, how long does it usually take for your hotend to heat up? what do you mean by this: made the spring tensioner with a ball bearing.? attached is the gear that i am using. is this the same as the MK7 gear? it seems like the gear I have does not have enough tension to even pull the 1.75 filament down

Any advice from the forum Pros gladly appreciated. Should i just buy a different extruder?


Janski

That looks like the stock gear.. the MK7 gear is from the makerbot.. it looks like this.


I have since found more information.. what I was looking for here was more of a confirmation that this is a heat too far up issue before I embarked on another mod..
So here is the mod I was talking about that I did.. you print some replacement parts for your extruders to get rid of the white plastic block and the set screw tensioner.. so you use a more makerbot style.. like this (seems to work pretty well so far..
qu-bd extruder mod

The last mod I am going to do, which should finish it off and make it work fine is this

qu-bd extruder ptfe liner mod

Edited 1 time(s). Last edit at 02/25/2014 02:33PM by ShreddinPB.

Or, if you dont have the skills to make the ptfe lined barrel, this guy is selling them on ebay
qu-bd ptfe lined barrel