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QU-BD MBE Extruder Issues

Posted by uMinded 
QU-BD MBE Extruder Issues
July 14, 2013 11:27PM
I am running a QU-BD MBE extruder on my Prusa I3 and having some strange issues. I can print great quality until it seems that an air pocket forms in the heat barel.

I print say 3-5 layers and then the PLA begins to turn dotty as if the temperature was too low and after about a layer it stops extruding. If I pause the print and release tention I can push about 10mm of filament in without any resistance and then I will feel resistance and the nozzle will start to eject plastic. I can then continue to print without any issues for 3-5 layers.

I find printing hotter and faster works better as if I print as 200c and 10mm/s then I can not even get the first layer down. But at 230c and 60mm/s I can print 3-5 layers.

I am not using the stock grub screw tightener but the buildlog.net mods So I have a spring tentioner and a MK7 driver. The entrance to the hot end is as tight to the idler bearing as possible.

Anybody have an idea what causes this "air pocket" sort of feeling?
Re: QU-BD MBE Extruder Issues
July 15, 2013 12:40AM
What is happening is the PLA is swelling from the creep up the barrel.
After hundreds of hours of trying to get PLA to run through the QU-BD extruder I installed PTFE tubing in the barrel.


I have made some one piece barrels and Mike has them for sale for $15 each. Email Mike at

mike at thewoodworker dot net

Re: QU-BD MBE Extruder Issues
July 15, 2013 06:58AM
Awesome thanks, I sent him an email.

While I am waiting would this be an issue with ABS? I imagine the higher melting temp would help with the creeping.
Re: QU-BD MBE Extruder Issues
July 15, 2013 08:45AM

$15ea shipped (lower 48USA only at this time) paypal gift to mike at thewoodworker dot net.

Due to the extreme distances and lovely handlers of packages, We cannot guarentee deliveries to Canada and Hawaii and Alaska or any international shipping so I am not shipping there at this time. When Rodney stocks us way up and we can afford to guarentee the barrel deliveries, then those locations will pay $15ea paypal gift and actual shipping.

Mike Heidrick
Re: QU-BD MBE Extruder Issues
July 15, 2013 11:34AM
Any way I can pay say $20 to get one in the mail? My printer is pretty much useless without this mod.....
Re: QU-BD MBE Extruder Issues
July 15, 2013 12:06PM
We can try it uMinded if you accept the risks. It will just be the same $15 to Canada. Pretty sure the rates do not change for a letter to CA.

Edited 1 time(s). Last edit at 07/15/2013 12:10PM by BloomingtonMike.
Re: QU-BD MBE Extruder Issues
July 15, 2013 12:36PM
Awesome, Thanks.

I will PayPal you right away. I will put my address in the transfers comments.
Re: QU-BD MBE Extruder Issues
July 15, 2013 03:00PM
Barrels are sold out. Thanks guys. We need more Rodney smiling smiley
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