kit for qubd extruder that works

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kbot3d
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kit for qubd extruder that works

Post by kbot3d » Sun Jun 09, 2013 9:29 pm

I have had a number of locals bring me their printers who have all purchased the $34 qubd extruder. Like everyone, I too bought a couple as you can't beat the price. The problem is the pressure screw in the white block is a joke. it just doesn't work. especially when you change from one filament to the next and find the same variations in filament i do. some are 1.6mm and the next 1.78mm even from the same manufacturer. I have about 40 rolls on hand and no two are exactly the same.

Which brings me to this post.

I spent the last 18 hours working on a simple solution to a simple problem. I tried ideas from the web and a few were promising. From there, I worked up my own borrowing from the best solution I could find and changing the leverage points. It uses a strong spring from Ace hardware and one 608 bearing I had on hand and replaces the white block and leaves the rest in place. The only issue I've found so far is setting it up is like threading a needle blind. You have to go by feel.

I would like to offer it to 5 people at cost plus shipping for testing. Roughly 5 to 10 dollars. I would prefer it go to someone that is already familiar with printing with one catch. I need feedback. Let me know if you are interested

kbot3d
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Re: kit for qubd extruder that works

Post by kbot3d » Mon Jun 10, 2013 4:10 am

for you makerslide fans, you may find this interesting or even amusing. my solution turns out to be a derivative of a derivative of a part modeled by bart dring. seems Im always two steps behind this guy lol.

Enraged
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Re: kit for qubd extruder that works

Post by Enraged » Mon Jun 10, 2013 6:03 am

my qubd mod was called the trash can.

cvoinescu
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Re: kit for qubd extruder that works

Post by cvoinescu » Mon Jun 10, 2013 10:04 am

Bart's mod is a derivative of yet another mod (but Bart's is simpler). These mods fix the QU-BD for ABS, but, as far as I can tell from the reviews, not always for PLA. PLA is trickier because it has very different flow properties (less viscous) and a sharp transition temperature (unlike ABS, which softens gradually). It flows up the barrel around the filament, solidifies, and jams it.
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kbot3d
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Re: kit for qubd extruder that works

Post by kbot3d » Mon Jun 10, 2013 4:12 pm

good to know. I've never bothered with pla. I stick to abs and nylon

JuiceBox
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Re: kit for qubd extruder that works

Post by JuiceBox » Tue Jun 18, 2013 5:34 am

Could ya perhaps post a picture of what you've done ?

bjbsquared
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Re: kit for qubd extruder that works

Post by bjbsquared » Tue Jun 18, 2013 10:01 am

cvoinescu wrote:Bart's mod is a derivative of yet another mod (but Bart's is simpler). These mods fix the QU-BD for ABS, but, as far as I can tell from the reviews, not always for PLA. PLA is trickier because it has very different flow properties (less viscous) and a sharp transition temperature (unlike ABS, which softens gradually). It flows up the barrel around the filament, solidifies, and jams it.
PLA is my preferred material. I keep the hot end temperature on the low side and a fan pointed at the top of the extruder barrel. Ive never had this flow reversal issue.
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kbot3d
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Re: kit for qubd extruder that works

Post by kbot3d » Tue Jun 18, 2013 6:26 pm

Two ideas for a fix. The first is a slightly modified version of a fix I found online. I simply adjusted two lengths from the original to improve leverage for better clamping force. The second will be tested this week when I can take down one of my printers. Why waste a perfectly good hotend? The feed is the problem. It will have three heatsink washers which are 1/8 sheet alum milled down to 1mm starting from 10mm off center to 25mm out. I retained the center section to tap for more material on material improving heat transfer and to eliminate need for nuts. Not a lot of room to work with here. Then I add my feed system and voila. The great part about this setup compared to using the hotend I currently use is both cost($15 compared to $65) and the ability to change tips on the fly. Some jobs need .5mm while others need finer like .35. That and many of us wasted money on the qubd only to throw it in a drawer. I know I did
Attachments
qu.jpg
qu.jpg (40.13 KiB) Viewed 2970 times

kbot3d
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Re: kit for qubd extruder that works

Post by kbot3d » Wed Jun 19, 2013 1:40 am

Update for hotend. 3 spacers milled and tapped from 1/8 alum. Yes washers could be used but I have the mill so why not use it. It also gives more contact to the stainless rod to draw out the heat.
Attachments
qu1.jpg
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