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Extruder Cleanup Options

Posted by SOI Sentinel 
Extruder Cleanup Options
October 18, 2007 02:23PM
I've read the posts over on the Hydraraptor blog about using a toothbrush head and a knife to clean up the expanding extruder material. nophead's now partially melting his toothbrush, and it still requires you to trek halfway across the machine to clean up. Not a concern when you only do it once or twice a part, but I can see issues if you need to clean up when doing discontinuous extruding.

Here's what I'm hoping to try when I get a chance. Take a very small motor or 180 degree rotary solenoid. Affix a bracket to the shaft with a 45 degree bend. You're probably going to want something that has useable properties in your extruder temperature band for this. Affix a thin (and possibly sharp!) piece of metal to this bracket. Affix this whole contraption on a bracket near your extruder nozzle at 45 degrees. The idea here is that when activated, the solenoid moves the blade from 90 degrees parallel to immediately underneath the nozzle. Control or spring return would reset the system when de-energized. This severs your material and can also act as a block to partially prevent drippy nose syndrome.

Blades extracted from a disposable razor would probably be just right. You'd want it sharp and wide enough to block the nozzle but not so wide as to be unweidly, and thin to reduce plastic displacement and to allow you to trigger the cutoff near the piece, thereby reducing stringing. Very useful for between layers or when non-continuously infilling. The major disadvantage is that you have something ELSE hanging off the extruder now. The blade and motor assembly, when in storage, at least can be made to normally rest above the work zone.

Anyone else have an idea on this?
Re: Extruder Cleanup Options
October 18, 2007 03:15PM

... ther is the fair possibility, that the extruded strings and droplets would stick to the knife and hang around, so they could kontaminate the building area, so a cleaner beside is safer.

I thought about a kind of revolver or endless ribbon, but it's the same, loose particles can fall down and stick to the actual slice ...

Re: Extruder Cleanup Options
October 18, 2007 03:41PM
You also need something for the knife to oppose against, otherwise the severed filament swings upwards and sticks to the side of the nozzle. My next attempt will be 20mm high block with a 2mm slot through it with the knife along one side of the slot. The dangling filament will enter along the slot and then move at right angles across the blade. That will force the offcut to fall.

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