Printable filament driver grab gear (photo)

I continue to share my ideas I developed for last year.
On the photo you could see grab gear I printed for filament driver.
It is basically plastic pulley with slots for metal inserts.
I cut m3 washers in half and injected them into slots by using soldering gun.

This is much easy to produce for me than hobbed bolt.
And it is perfect for latest extruder designes where metal gear used as driver.

I used 0.5 mm washers but also possible to use shim washers 0.1mm 0.2mm thick.
Also it is possible to put them not at right angle but more sharp angle for better grab in pushing direction.

Looks like a nice simple idea. Have you tested it much to see if there are any wear issues?

Tim

Actually not yet on printer. I just tried it manually on filament. And it has more friction than hobbed bolt. And it not slip on filament. But hobbed bolt slips and makes sanding effect.

At the moment I do not want to change anything in my existing printer just because it is in use.
But I am working on absolutely new 3D printer design and this grab gear will be part of it.

Nice design but I am not sure if having the wheel made out of the same material as being printed will work. Since you want the teeth to sink into the filament being driven you need to have enough force on the idler that I could see the teeth just being pushed into the wheel until they are flush and no longer work.

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Sweet. I can't wait to see if this works.

Sublime Wrote:
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> Nice design but I am not sure if having the wheel
> made out of the same material as being printed
> will work. Since you want the teeth to sink into
> the filament being driven you need to have enough
> force on the idler that I could see the teeth just
> being pushed into the wheel until they are flush
> and no longer work.


Theoretically the surface area of the part of the tooth touching the gear is larger than the surface area grabbing the filament, so the force will be spread out more on the gear side and should not dig in as much as on the filament. You could also glue the metal teeth into the gear. But if you clamp down hard on the idler roller, i could see what you describe happening.

Actually You already add a lot more grip by increasing the diameter of the wheel. So if You would hob lets say a M12 instead of a M8 bolt You would have also more traction/less slippage. What You obviously trade in when You increase the diameter is the resolution of the "E-axis", as well as torque. So You need to have a bigger reduction in gears to achieve same torque and resolution...

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