Leveraging a 3D printer “defect” to create a new quasi-textile • Hacker News Board

Re: Leveraging a 3D printer “defect” to create a new quasi-textile

#41

Post by Cactus2018 » Fri, Oct 30, 2020, 4:38 PM UTC

eigenvalue wrote: post #31

Seems to me like this works on the same principles as these big machines used to make plastic netting for fruits: https://www.alibaba.com/product-detail/Fruit-net-machine_620... But $300 is a lot more accessible than $5,000, and it's a lot more customizable.

There are some great 'how its made' videos on youtube under combinations of search terms like

    circular loom weaving machine

Plastic netting for fruits https://www.youtube.com/watch?v=4FG2d97nxSg

Lexus CF printing promo https://www.youtube.com/watch?v=kttvDaUIWCs

Re: Leveraging a 3D printer “defect” to create a new quasi-textile

#42

Post by lylecheatham » Fri, Oct 30, 2020, 5:26 PM UTC

himinlomax wrote: post #28

londons_explore wrote: post #12

I've run a 3d printer with the extrusion rate way down before (to try and produce very thin surfaces), and the results were far less consistent. I got big holes in my parts and massive dribbles and blobs in other places. I wonder how these results can be so so so much better in comparison?

It looks like it works not by constantly underextruding, but only intermittently. The parts where the strands join are overextruded if anything.

I'm pretty sure it's actually just a continuous under extrusion. It becomes periodic in nature because material gathers under the nozzle and then it hits the blob from the previous layer and gets pulled off. It's a similar effect to how droplets form and fall off of your faucet when the flow rate is low. This also leads to the diagonal angles seen as the Z-height goes up.

It's usually hard to get this to happen consistently, which they've done quite well.

I've got no citations, but I worked in FDM Additive Manufacturing for a few years, and spent 4 months of that designing extruders for a name brand company.

Re: Leveraging a 3D printer “defect” to create a new quasi-textile

#43

Post by lylecheatham » Fri, Oct 30, 2020, 5:32 PM UTC

curiousllama wrote: post #21

rhklein wrote: post #13

Earlier quoted context omitted.

Most like some postprocessing in the gcode to multiply the extrusion rate by some factor for each blob.

Probably some combination. They used a cheap printer - I can't imagine those little prusa motors and gears are particularly precise with high-frequency, micro changes, even if they can get good consistency

You'd be surprised actually! Prusa uses no gearing between the motor and the primary drive gear and it's a 200 step/rev NEMA 17.

You can transmit high frequencies quite easily, and I've actually seen bad stepper motors with high cogging torque transmit that periodic torque as an extrusion defect into walls with the correct thickness.

Re: Leveraging a 3D printer “defect” to create a new quasi-textile

#44

Post by eudes_ochoa » Fri, Oct 30, 2020, 6:15 PM UTC

londons_explore wrote: post #12

I've run a 3d printer with the extrusion rate way down before (to try and produce very thin surfaces), and the results were far less consistent. I got big holes in my parts and massive dribbles and blobs in other places. I wonder how these results can be so so so much better in comparison?

here's the author explaining how to achieve the print: https://twitter.com/FormanForm/status/1315759308450062336?s=...

Re: Leveraging a 3D printer “defect” to create a new quasi-textile

#45

Post by londons_explore » Fri, Oct 30, 2020, 10:29 PM UTC

lylecheatham wrote: post #42

himinlomax wrote: post #28

Earlier quoted context omitted.

It looks like it works not by constantly underextruding, but only intermittently. The parts where the strands join are overextruded if anything.

I'm pretty sure it's actually just a continuous under extrusion. It becomes periodic in nature because material gathers under the nozzle and then it hits the blob from the previous layer and gets pulled off. It's a similar effect to how droplets form and fall off of your faucet when the flow rate is low. This also leads to the diagonal angles seen as the Z-height goes up. It's usually hard to get this to happen consi…

What surprises me is quite how consistent it is. The blobs look perfectly consistent over thousands of layers, which seems very unlikely - even a tiny perturbation would grow bigger in each successive layer and eventually cause the blobs to be chaotic in nature, even if the first row was consistent.

Re: Leveraging a 3D printer “defect” to create a new quasi-textile

#46

Post by himinlomax » Sun, Nov 01, 2020, 8:52 AM UTC

lylecheatham wrote: post #42

himinlomax wrote: post #28

Earlier quoted context omitted.

It looks like it works not by constantly underextruding, but only intermittently. The parts where the strands join are overextruded if anything.

I'm pretty sure it's actually just a continuous under extrusion. It becomes periodic in nature because material gathers under the nozzle and then it hits the blob from the previous layer and gets pulled off. It's a similar effect to how droplets form and fall off of your faucet when the flow rate is low. This also leads to the diagonal angles seen as the Z-height goes up. It's usually hard to get this to happen consi…

I wouldn't be so sure, I saw a video of variable infill extrusion and it looked somewhat like this, although over a greater distance but otoh much faster. Speaking of which, it seems to be printing quite slowly.