Different nozzle shape = long slot?

I'm curious if there has been any experimentation with different extruder nozzle shapes.

My thought was to have a slotted nozzle instead of a circle. Consider a rectangular slot with a width comparable to a current nozzle, but about 1cm in length.

Now, mount the nozzle so that the slot can be rotated through 90 degrees using a servo.

Think about using this nozzle as you would a calligraphy pen. Extrude with the nozzle traveling in line with its narrowest dimension, you could get a plot of similar width to one from a conventional nozzle. Extrude along the long dimension and you could lay down large fills in a fraction of the time of a conventional nozzle.

There would be some plot limitations imposed by the nozzle, but not really that many with some creative software and perhaps a few tweaks to existing designs.

Anyway... just brainstorming.

Cheers,
Al

The implementation issue I could see is how you would maintain the seal between the nozzle and heater barrel, assuming its just the nozzle you're rotating. Or if you're rotating it from the thermal break downward, how do you avoid catching the unmelted portion of the filiment and torquing it.

There's actually no need for a servo, if you use two print heads and are willing to lay down parallelograms instead of squares. I mentioned idea like this a while ago but I haven't tested it yet. Hoping to get around to that this year...

It should be extremely easy to make this kind of nozzle. The slicing software will need to be changed; that would take the most work. But the algorithm itself isn't too difficult; you can subtract the wide parallelograms from the original slice and send the resulting shape back to the original algorithm to fill in the smaller lines.

Trying to use a servo to orient the nozzle along the narrow dimension would probably be a poor substitute for a small round nozzle. For one, when you try to go around a tight-radius bend, the line will get smeared out. It would also present more difficulties when trying to move in a straight line... The plastic coming out of the rear end of the nozzle would always be running overtop of the plastic coming out of the front end, which might cause it to spread outwards.

Edited 2 time(s). Last edit at 09/02/2011 10:18PM by jbayless.

jbayless Wrote:
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> There's actually no need for a servo, if you use
> two print heads and are willing to lay down
> parallelograms instead of squares. I mentioned
> idea like this a while ago but I haven't tested it
> yet. Hoping to get around to that this year...

But if you're going for two print heads, why not just have two different round nozzles? The latest Skeinforge developments already know how to construct the object skin from thinner layers than the inside. That would work even better if you could use a thinner nozzle for the object skin and a thicker one for the infill. The slotted nozzle might have uses in some cases, but wouldn't two differently sized round nozzles be a more generally useful solution?

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The latest Skeinforge developments already know how to construct the object skin from thinner layers than the inside.

Do they or is this just the bodge that Josef Prusa originated? What happens when the wall steps in or out, how does it fill the sloping void with filament that is twice the height?

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