Pultrusion not Extrusion

The most successful technology, as Bowyer postulated, is that which draws from nature. I've always admired spider webs. Yes, I said spider webs. Am I crazy? Maybe, but that's another discussion.

A spider excretes 2 substances, that mix together to form silk. The spider excretes the silk in a process called pultrusion. This "pultrusion" forms the web which the spider uses to eat it's breakfast, lunch, and dinner.

This is very different from the process of 3D printing, in which plastic is extruded. However, the reprap model is to draw from nature to advance the machinery of 3D printing. Now, the first 3D printers were arachnids, not homosapiens, therefore, the next logical step of the reprap project should be to emulate the chemical process of pultrusion.

This might not be the easiest way to go about things, but I think it's an avenue which has been overlooked. How exactly to go about it, I'm not sure. I was thinking of using a canister of hairspray to mix with some other substance, through a standard extrusion nozzle. Any input would be appreciated.

I don't think pultrusion is the appropriate word. Pultrusion (see Wikipedia) involves something being pulled through a die and doesn't have to involve the combination of two chemicals. I can't see how a spider could "pultrude" because the component chemicals are unlikely to have any tensile strength until they have left its body and mixed.

However the idea of extruding one or two liquid chemicals which harden when mixed (epoxy and hardner perhaps) or which harden on contact with air (superglue?) is intriguing. Another possibility might be extrude a stiff paste that has sufficient "body" to hold its shape until it hardens.

I think the challenge will be to find something that hardens fast enough but not so fast that it ruins the extruder. And I suspect it will be more difficult as the extruded diameter decreases.

...R

amide bonds, polyamide. such as nylon?

Printing with 2-part thermosetting polymer

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Robin2
I don't think pultrusion is the appropriate word. Pultrusion (see Wikipedia) involves something being pulled through a die and doesn't have to involve the combination of two chemicals. I can't see how a spider could "pultrude" because the component chemicals are unlikely to have any tensile strength until they have left its body and mixed.

However the idea of extruding one or two liquid chemicals which harden when mixed (epoxy and hardner perhaps) or which harden on contact with air (superglue?) is intriguing. Another possibility might be extrude a stiff paste that has sufficient "body" to hold its shape until it hardens.

I think the challenge will be to find something that hardens fast enough but not so fast that it ruins the extruder. And I suspect it will be more difficult as the extruded diameter decreases.

...R

How about the UV curing resins? A UV light outside of the extruder shining on the part as it is being printed would allow the resin to set almost immediately and also would not require any heat in the process.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

The problem with 2 part solutions and uv curing is that it doesn't achieve the necessary "pull" or downward force to bring the resin out of the nozzle. The adhesion to the substrate, the print bed on the first layer and the extruded plastic on the rest of the layers, would need to provide all of the force necessary force to draw the filament out.

Given that that force is extremely small, I think it could only be possible with extremely small filament. However, the advantage would be that it wouldn't require a motor to drive the filament, or it'd use just a small dc motor to get it started.

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ohioplastics
The problem with 2 part solutions and uv curing is that it doesn't achieve the necessary "pull" or downward force to bring the resin out of the nozzle. The adhesion to the substrate, the print bed on the first layer and the extruded plastic on the rest of the layers, would need to provide all of the force necessary force to draw the filament out.

Given that that force is extremely small, I think it could only be possible with extremely small filament. However, the advantage would be that it wouldn't require a motor to drive the filament, or it'd use just a small dc motor to get it started.

That's not an issue if you extrude the components. In my view this thread is poorly named.

...R