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QU-BD open source extruder

by Modpod, published

QU-BD open source extruder by Modpod Jul 25, 2012

Description

QU-BD's extruder converted from QU-BD's STL files

Recent Comments

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I've been waiting for more people to give feed back on how well the QU-BD unit works.  I have already seen a few say they have stalled the motor when they tighten the set screw.  Her instructions were to tighten the set screw until it feeds and than give it an additional 1/4 turn.  Maybe?  Would be nice if it worked well and was that simple. 

On the other hand - now that I've figured out what a Bowden drive is - I would love to mount the feeder off on the side like a mig welder to save some weight and pack double heads really close together.  From what I've read the one big draw back is that the filiment can flex or compress in the tube like a spring - creating pressure on the nozzle even when the extruder pauses.  Maybe not the best option.

The only places I can see that the heat sink makes contact on the QU-BD head is with the UHMW piece and the the other piece (i think aluminum) that the stainless tube threads into.  I do not see the heat sink physically in contact with the stainless tube.  

Do you have any proven back ground on what really works best?  I have read where some guys want a long heat area to reduce tip pressure and I have read where other guys try to keep the heat at as close to the tip as possible to reduce jams.  Who's right?  If we use peek or glass filled PTFE we have a great insolator and force all the heat in the tip. 

Can you define why the Bowden re-design would require the changes you mentioned below.

 
It would be interesting to see what you come up with as a replacement for the set screw. There has been some discussion on the buildlog.net forum, but I dont think anyone has made anything yet.

I have been holding off on the bowden re-design since Chelsea (QU-BD) hinted that they may be doing something.

A bowden re-design would require a replacement to the stainless tube that connects the hot end with the heat sink above, as well as a  replacement for the heatsink, and an insulated holder. something like the PEEK holder that the J-head uses would be ideal.
I would appreciate seeing what you come up with.  I have not seen enough extruders apart to compare this QU-BD version.  Looks like they use a flat set screw to push the filament into the gear - hard to believe that works very well.  Not to many people with feed back yet.  She is selling the parts at fair prices though.

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Instructions

QU-BD have been reluctant to publish usable solids files of their open source extruder, so I downloaded their STL's and rebuilt, then created an assembly file.

The asssembly also contains two mounting plates that are not shown in the screenshots.

There are two files: The STEP file is 951kb and a .SAT file which is 1mb.

I will be working on converting this to a bowden type extruder and will publish once I have something worth sharing.
I've been waiting for more people to give feed back on how well the QU-BD unit works.  I have already seen a few say they have stalled the motor when they tighten the set screw.  Her instructions were to tighten the set screw until it feeds and than give it an additional 1/4 turn.  Maybe?  Would be nice if it worked well and was that simple. 

On the other hand - now that I've figured out what a Bowden drive is - I would love to mount the feeder off on the side like a mig welder to save some weight and pack double heads really close together.  From what I've read the one big draw back is that the filiment can flex or compress in the tube like a spring - creating pressure on the nozzle even when the extruder pauses.  Maybe not the best option.

The only places I can see that the heat sink makes contact on the QU-BD head is with the UHMW piece and the the other piece (i think aluminum) that the stainless tube threads into.  I do not see the heat sink physically in contact with the stainless tube.  

Do you have any proven back ground on what really works best?  I have read where some guys want a long heat area to reduce tip pressure and I have read where other guys try to keep the heat at as close to the tip as possible to reduce jams.  Who's right?  If we use peek or glass filled PTFE we have a great insolator and force all the heat in the tip. 

Can you define why the Bowden re-design would require the changes you mentioned below.

 
It would be interesting to see what you come up with as a replacement for the set screw. There has been some discussion on the buildlog.net forum, but I dont think anyone has made anything yet.

I have been holding off on the bowden re-design since Chelsea (QU-BD) hinted that they may be doing something.

A bowden re-design would require a replacement to the stainless tube that connects the hot end with the heat sink above, as well as a  replacement for the heatsink, and an insulated holder. something like the PEEK holder that the J-head uses would be ideal.
I would appreciate seeing what you come up with.  I have not seen enough extruders apart to compare this QU-BD version.  Looks like they use a flat set screw to push the filament into the gear - hard to believe that works very well.  Not to many people with feed back yet.  She is selling the parts at fair prices though.
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