Using 2 extruder with a single stepper

audryhome

Hi there,

I am trying to figure out how to drive an hypothetic double extruder whose stepper would be mechanically switched from a single driver, who could be mapper to, for instance E0 and E1 with a separate macro that would drive some clutch through, say , a servo.

Could not try this for the moment, my printer has only one extruder.

Many thanks for help

fcwilt

It could be done.

You might have to issue the extruder stepper configuration commands when switching from one to the other.

The multiple tool handling features of the firmware would be used for this.

Frederick

theruttmeister

@audryhome
https://patents.google.com/patent/US7604470B2/en

audryhome

@theruttmeister Thanks for the info, that's more or less the same idea, using Orbiters extruders, which use lightweight steppers with an epicycloidal gearbox.

BatLord

@theruttmeister A really great guide!

theruttmeister

@audryhome said in Using 2 extruder with a single stepper:

@theruttmeister Thanks for the info, that's more or less the same idea, using Orbiters extruders, which use lightweight steppers with an epicycloidal gearbox.

Ahem... its an ordinary planetary gearbox

The Stratasys design probably uses a brushless servo with integral multi-stage planetary gearbox... they aren't too worried about costs.
The advantage of a common motor might be cost, but its more likely size. That head is significantly more compact, plus if done correctly, registration between nozzles should be really good.
Its a very elegant way to move the unused nozzle out of the way.
That aspect is probably out of patent (as the whole 'moving the nozzle up and down' concept is in an earlier one that I think has passed) but using a single motor for two extruders is still covered for a few years.

Their earlier designs used a strange single/double nozzle. Slightly better than two separate nozzles that don't move, but still not great.

The real challenge for using a single motor with two extruders is coming up with something that isn't just as heavy, complicated or expensive as using two motors.

zapta

@theruttmeister said in Using 2 extruder with a single stepper:

... using a single motor for two extruders is still covered

Looking at the claims of this patent, it also require that each of the two will work on a reversed motor direction, so if you find a different way, it will be a valid workaround. (not that it matter for makers and hobbyists).

Anybody knows if this design actually works and used in a product? Sometimes companies file patents just to be on the safe side.