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Quick attach or remove nozzle, so we can change from 1mm to 0.3mm hole

Posted by casainho 
Quick attach or remove nozzle, so we can change from 1mm to 0.3mm hole
March 19, 2010 03:48PM
Hello :-)

I think many of us would like to have a few extruders, so we can quickly change from printing PLA to ABS, etc. Also changing the nozzle hole size would let use printing with more quality VS printing time.

If someone could build a system where nozzle is quick replaceable (and no need to change the thermistor) ...

NOTE: Makergear have one kind of thing for the heater.

Edited 1 time(s). Last edit at 03/19/2010 03:52PM by casainho.

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Re: Quick attach or remove nozzle, so we can change from 1mm to 0.3mm hole
March 19, 2010 04:22PM
Its probably easiest to use a whole separate heater/barrel/nozzle for each plastic, or you'll have to somehow purge the system each time you want to change plastics. As far as I can see, this gives you two main options:

Make multiple bowden extruders. The small size of the nozzle apparatus means they could easily be switched mid-build, so support materials would become possible.

Make each extruder very modular, so they can be swapped by hand when needed. This saves on electronics and steppers and is easier, but arguably less useful.
Re: Quick attach or remove nozzle, so we can change from 1mm to 0.3mm hole
March 22, 2010 10:04AM
casainho

Have you ever see the microscope with three or more magnifications? The have a rotating part with each bottom stage optics in one tube. The whole stage rotates at an angle, and each tube is angled out so that when it is in place, it looks straight down, and the other two are rotated well out of the way to prevent accidentally bumping the slide or object being examined.

I think the same rotating stage with 3 different size nozzle tips would work great for getting different flow rates from a single type of plastic. For switching from ABS to PLA, I would strongly suggest a separate extruder head for each, which eliminates cross contamination. Then you can also optimize it for temperature and nozzle sizes.

Still haven't built my own 3 size nozzle, but getting a good start on me very first extruder. I will make a wiki page on how to make the extruder without a lathe.

Mike


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Re: Quick attach or remove nozzle, so we can change from 1mm to 0.3mm hole
March 22, 2010 12:07PM
That's a really good idea about the microscope changing thing, I've been thinking about it but I can see some problems that personally I can't see how I'd get around. Firstly, the transition bit between movable barrel and fixed body - It either has to be where the filament is solid, but it then has to crunch/cut the filament and PLA is pretty tough, plus you then need some non-reprappable blades and a geared stepper for the torque. If its where the filament is molten, particularly with PLA, it will leak through /any/ gap. I've had it escape up 1cm of M6 thread, so it'd be pretty difficult to contain, especially with moving parts. The other potential problem is that PLA will keep dribbling under gravity even with the motor off, so you'd have to block the end of each nozzle, and make sure not to introduce air bubbles when you resume printing.

Please don't think I'm bashing ideas, I'm hopeful someone can think around these problems.
Re: Quick attach or remove nozzle, so we can change from 1mm to 0.3mm hole
March 22, 2010 10:49PM
If the tip-switching process was motor-controlled, you could switch from a fine-detail extruder for the outline to a coarse, large-diameter nozzle for the infill. Just a thought. smiling smiley

But I don't see 3D printed parts being suitable for this application, since the nozzle tip is subjected to high heat. Therefore, parts will either need to be custom-machined, easily sourced from other things (mechanical pencils, spare microscopes...), or provided by a supplier like Makerbot.
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