Results 21 to 30 of 31
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07-06-2016, 05:02 PM #21
I have been thinking about retracting the hot ends for a while. The video below didn't work for me, so I'm not sure what it shows. [Edit: Ahh...beerdart, so this is the spring-loaded hollow-bolt hot ends?] There is at least one rocking extruder system on Thingiverse that uses a servo and a cam to rock the whole assembly left and right, pushing the unused tip onto a metal spring to stop the ooze. There are also various hot end setups that use the filament pressure to force the hot end downward against spring pressure.
I have looked at the rocking option, but didn't immediately come up with anything I loved. The biggest challenge with is the pivot. Getting something rigid, precise and repeatable with off-the-shelf parts (3D printed and common bearings) is tough. Maybe I'll keep playing with it.
Another idea that's floating around out there is independent hot end assemblies that can be picked up by the carriage with electromagnets and parked at the side of the printer when not in use. This would pretty much have to be a bowden setup.Last edited by clough42; 07-06-2016 at 05:06 PM. Reason: Added more detail
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07-07-2016, 07:50 AM #22
The hollow bolt was v1 the vid is v2. Its a E3D hotend with the top groove machined off and a new top hat attached with a hollow flat head screw. The mounting plate was thickened and a tight tolerance brass bushing pressed in and a wave spring is used for retract. Ill snap some pics next time one is off.
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07-07-2016, 10:01 AM #23
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I would really like to see improvements for multiple filament printing. Maybe I just haven't spent enough time tuning my printer, but the inevitable ooze from the unused hot-end almost always ends up with a nib that breaks the print loose, or drips some unwanted color/material into the print. The temperature drop/retraction method for the inactive extruder works fairly well, and the pillars method wastes too much filament to be practical in my opinion. The retracting hot ends I have seen seem unduly complicated and I question repeatability with reasonable accuracy.
I have seen a couple of clever servo mounted wipers for the nozzles on delta printers, but have not seen it implemented in a prusa frame as of yet. Would it be possible to mount something like that on the X carriage (so as to move with the Z axis)?
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07-09-2016, 10:28 PM #24
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07-09-2016, 10:37 PM #25
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Hi
One "obvious" solution to the drip drip drip might be to drop the temperature on the hot end when it's not in use. Yes that has zip to do with extruder design ...
Bob
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07-18-2016, 12:37 PM #26
Most slicers that support dual extrusion have this option. It definitely helps, at the expense of print speed.
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10-01-2016, 03:13 PM #27
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10-02-2016, 01:27 AM #28
Have to get you and anvil and a forge. Hehe
I know what you mean though. I would love to be able to print strong metal parts. It would solve some issues on the farm when something obscure breaks and you need a replacement in a short amount of time not a week or more.Editor in Chief
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10-02-2016, 01:35 AM #29Editor in Chief
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10-03-2016, 09:01 PM #30
Thanks for posting the photos. That looks really good. How much vertical motion does it produce, and how does it register? Does the washer bottom consistently? Do you get any X/Y artifacts?
I was thinking about something like this over the weekend, and this is very similar to what I was designing in my head, except my imaginary design had a much longer vertical stroke. Perhaps it isn't needed?
What's with the nozzle? That doesn't look like an E3D part.
James
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