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

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

news.mit.edu

136 pointsDoreenMichele45 comments

Read somewhere that there’s a whole field of research dedicated to mathematically designed, non-flat textiles.

If you think of it, all we do currently is cut and sew flat tiles of deformable cloth to approximate whatever curvature, but if you can print the material with the curvatures embedded it’s an interesting path to explore

Nike Flyknit shoes have this technology: https://www.nike.com/flyknit

They weave different densities and materials in different sections of the upper to make some areas stronger, some more breathable, some stretchy, etc. You may have seen it referenced in some of the recent furor over the Next% carbon midplate.

North Sails' 3Di tech? They make precisely curved sails for racing yachts. https://www.northsails.com/sailing/en/innovation/3di-technol...

Finally someone solved the problem of sold out toilet paper in the pandemic

PLA toilet paper - It has holes, no absorbtion, sharp edges, and takes an hour per square to print.

Sign me up!

I transitioned to sea shells to fix this problem

3 3D printed sea shells?

Wood infused for that all natural feeling

Bidets are a worthwhile investment.

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

This is fantastic. I'm reminded of the 3D printed broom from a few years ago. I remember being blown away in a similar fashion then. This type of under extrusion can create very thin filaments, but the Gcode to generate these structures isn't easy to create with the traditional model=>slicer=>Gcode software stack.

I've been out of the loop for a couple of years though, so I'm interested to know if this has evolved much.

I think it's fair to say there have been sweeping changes.

I wrote a G-code Importer for Blender recently. Having access to the toolpaths directly lets you do some interesting things conventional slicers can't do. [link redacted]

I've been experimenting with storing extrusion multiplier info inside Blender to make weighted extrusion values based on a texture.

I wonder if they just used a custom slicer. In undergrad, I wrote my own slicer and used it to do silly things (less "can I make this?" than "What would happen if?").

I would imagine they took a similar (though, obviously, much more intelligent) approach here, just thinking directly in terms of slicer features, rather than in terms of models.

Gcode for this type of 3d printer is very easy to understand and generate.

Some years ago I did some experiments with 3d printing in 3d (printing wire frames in 3d).

But it takes time to get the feed rates and print speeds right.

Edit: an example of wireframe printing: http://www.creativeapplications.net/wp-content/uploads/2014/...

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?

From my limited expirience, temperature of the extruded material must be in some narrow window, too cold or too hot and it will clump. Even within the window, the production of sticky hairs (what one would aim for in this case) varies a lot with temperature.

I can also imagine that the material plays a huge role, but I cannot say because I've only really used PLA.

The desired result is that you get a series of pulses of extrusion rather than random under-extrusion, so if you can't get consistent pulsing by adjusting temperature and extrustion rate, you could always hack Marlin to do it on purpose. I expect that is what they've done.

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.

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.

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.

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

Out of curiosity, what printer would they be using for something like this? I've been considering getting a 3D-printer for a while, but I don't know enough to decide which one to get.

It looked like they were using the Prusa I3 MK3S.

Just get Prusa. It’s used both by professionals and amateurs. In case it won’t be enough for your use, you will already know enough details about 3D printing to choose your next printer.

If you have the money and want a high quality FDM printer, buy a prusa. If you are on a budget get something like an Ender-3

This model is what I first got, and liked. Fun to put together and mess with. Won't print anything crazy, but will be plenty fun to play with.

https://shop.prusa3d.com/en/upgrades/183-original-prusa-i3-m...

I did an Ask HN [0] on this topic a few months ago and the answer was a Prusa I3 MK3S if you can afford it and the Creality Ender 3 if your budget is smaller.

I did get the Prusa I3 MK3S and it's just incredible, I'm astounded by the quality of the prints and the printer itself. I've already designed a number of parts in Fusion360 and printed them with a variety of different filaments (Flex, PLA, PETG) and having a lot of fun creating things!

[0] https://news.ycombinator.com/item?id=24032659

If you want to print fast get a delta.

Is the extruder speeding up and slowing down for each "blob" in the texture? Or is the extruder going constant speed and you're relying on surface tension to make the blobbyness?

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.

Hmmm, I wonder if a dual extruder printer using conductive filament in one nozzle could print flexible fabric circuit boards? Embed cabling for leds/elwire directly into the fabric?

I suspect it would be exceedingly difficult to get enough conductive materials in the mix, while also sufficiently purging to insulate between different traces/threads.

Perhaps printing an outfit entirely from conductive threads could be used to create a grounded Faraday cage suit/dress.

Purging might not be a probelm with dual extruders? The "trick" that makes it possible might not work without all the filament coming out of a single extruder nozzle in a connected spiderweb though...

Such conductive garments already exist in the form of fencing lamés, and other special-purpose wear which is used by electricians.

A fun fact is that whilst wearing a fencing lamé, one is generally impervious to tasers and stun guns.

Also as a cheaper alternative one can wrap themself in foil tape.

This seems cool but my imagination doesn’t seem to be working today. I can’t seem to think of any interesting applications of this.

There is literally a video with applications in the link.

I skimmed it. I guess I missed that.

Very interested in the badminton shuttlecock implementation. Wonder if it can be superior to current plastic shuttlecocks.

Wow. Mind blown.

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