Multiple filament driver

Hi,

I'm just posting this here for posterity, since I don't plan to pursue it (at least, for quite a while). Stratasys' print heads have a mechanism for swapping between two filaments with a single drive motor. Here's a plan for a variant of Wade's extruder that can swap between an arbitrary number of filaments with a single drive motor.

The image below shows the view from two different angles. In grey is the drive motor and gear train. Green is the drive shaft, hobbed in multiple places. In this illustration, there are three different filaments (red, blue, yellow). They each pass through two ball bearings (instead of one). One ball bearing acts just like in Wade's extruder, to squeeze the filament against the drive shaft. The second bearing is just for pulling the filament away from the drive shaft. It can easily be a solid rod rather than a bearing, as rolling contact is not needed. These bearings are mounted on plates, and the plates are all hinged about a common point. This allows each filament to independently be engaged or disengaged from the drive shaft. Each one of these can be independently actuated, but it's more economical to drive them all from a single motor. In this illustration, a camshaft is used to engage or disengage the various filaments, so only a single actuator is required for selecting filaments.

Let me know if the description is too vague and I can post some clarifications.

Edited 1 time(s). Last edit at 08/20/2011 01:37PM by jbayless.

Looks good, jbayless. Especially this camshaft thing.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

[www.thingiverse.com]

I've been doing some work on a similar concept myself. I have an almost working prototype. Getting there...

Ah, cool! That's a neat stepper motor cam-attachment; where did you find that?