I made custom 3D printing filament with my Logo inside!

[@CNCKitchen]

*QUESTION:* Which material combinations would you like to see and why? Want to get your 3D prints to the next level already today? Check out our Heat Set Inserts and Tools at cnckitchen.store (Free shipping worldwide starting at €100).

[@Some-nerd-who-tinkers]

Mix carbon fiber PETG with ninja flex TPU

[@eskanderx1027]

ABS + chocolate 😋

[@Some-nerd-who-tinkers]

Fiber glass composite pla 😋😋😋

[@RENATINHOBR99]

maybe PLA with a core of water soluble support like polydissolve, maybe to do some really light weight prints, insted of solid lines you will get tubes of PLA

[@lucasverocai1631]

This process can indeed open a path to multimaterial filament such as continuous carbon/glass fiber core embedded (inside an easy to respool material at first, for test purposes), the non strech fiber mechanical properties might be a hassle to deal with though... PA6/12, PC, TPU or Nylon for high end continuous fiber embedded filament, but might be even trickier to process. Anyway, good luck if you try this. Great video as always !

[@timseguine2]

"Yo Dawg, I heard you like layer adhesion problems. So I put layers in your filament so you can have layer adhesion problems while you're having layer adhesion problems."

[@ericwheelhouse4371]

You are having adhesion problems with pla?

[@timseguine2]

@@ericwheelhouse4371 14:28

[@djordjezivic2481]

@@ericwheelhouse4371 never under estimate a bad printer (my 2018 wanhao duplicator i3)

[@stevrgrs]

So basically you’re doing what candy makers have done for over 100 years :P 😂

[@comethiburs2326]

@@stevrgrs candy makers dont make candy with two different plastics and different melting points. Stuffed candy is generally coated or injected, as for hard candy it's rarely if ever done with a mix of, let's say butter based caramel and hard candy, as the butter caramel would leak out of the strip before it hardens, ruining the pattern. Irony or not it's apple to oranges. he's right about temp differentials being a problem with multimaterial printing.

[@dittot]

Roughly every year or so, someone makes a completely game-changing 3D printing video showcasing an inventive new way of doing things which could open up so many new possibilities. This is one of those.

[@StarkRG]

And at least a third of those seem to be done by CNC Kitchen. How many of the things Stephan has showcased over the years have become standard practice?

[@TD-er]

Yep I was wondering which 3D printer manufacturer is also watching this and thinking to add a filament-diameter scanner into the printhead to be able to automatically compensate for under/over extrusion during printing. Maybe this is even more important for flexible filaments to get a really consistent printing results?

[@givemeanameman1]

Its interesting, but its already being done... Continuous Carbon Fiber filaments for high strength parts for example. "fiber" filaments rarely have increased strength, because the fibers have to be chopped up so small that they don't do much. So Continuous Carbon Fiber filament and the like were invented to change this. The game changer is being able to make multifilament at home, even as a proof of concept.

[@mannycrafts]

Wow, this is insane. Mans maxed out his engineering level and just grinding sidequests now.

[@Some-nerd-who-tinkers]

He’s completed the CNC part of his username and will soon begin the Kitchen stage. Edit: tbh he’s already cooking

[@hyozanhades09]

He is manufacturing a new reality for earth in his kitchen !!!

[@ameliabuns4058]

Lol

[@drummerboymaddux]

😂😂

[@brandonsaffell4100]

If you think our man has reached his final form you underestimate him.

[@OldCurmudgeon3DP]

Hard candy is made in a similar fashion. All the design is created in a large (8-9" diameter) chunk then stretched into the final bite-size form. The pattern is retained through the stretching process same as with yours.

[@EFLO3D]

Same with “millefiori” glass art.

[@benjaminvdvyt]

This was the first thing that came to mind. Watching how candy is made, is extremely similar and follow the same principles.

[@OG-ProfessorFarnsworth]

His old video about the PC core ABS he mentioned actually talks about the same thing. I believe the original researchers made large blanks with the desired pattern that they then had a machine to extrude into a filament. Exactly what you’re thinking! But requires specialized equipment. Assuming I’m remembering correctly! 😅

[@wakafeek]

Beat me to it! I was about to say this is how they do designs in saltwater taffy too

[@dooleve]

Funnily enough, this is mentioned in the subtitles at 13:58, but he doesn't say it out loud

[@whatevernamegoeshere3644]

I work maintenance in a cable factory. The first 5 minutes of the video were pretty much most accessories of an extruder re-invented lol. You should really look up Kabmak extruders to get some inspirations because there are things like vacuum attachments and straightening rollers that could be added even to your machines. You could also add a mechanical brake to the pay-off spool to add pre-tensioning and it would make the plastic more consistent as it would feed through straight. The rollers serve the same purpose, but for wobbly lines. Another important addition would be a hot air blower to pre-heat the filament so you couldn't have to run a volcano type nozzle or anything special. You would need a lot less forces on that filament if it went into the nozzle already at say 50C. As for what you could be adding to it? Oh boy! Make 3 separate filament pay-offs with U-shaped "shells" on 2 of them and one filler. You could just add nylon strings or fishing line to the center spool and print multiple times as much filament at once. Hell, add a caterpillar-type tensioner brake to it and you're gonna have time to change filament on the go without interruption if you find a way to weld them in between.

[@jakeharms1386]

Thank you so much. This is exactly what I wish every comment on KZbin was like

[@shawnalfaro6943]

I agree with all of these suggestions! Preheating the filament is a great idea, even with something simple as a halogen light bulb. And the roller suggestion is also great!

[@Sparkynutz81]

Preheat the filament too was first thing I thought when he was struggling to pull it through too. Can't believe he didn't think of that when he was basically already doing that to stretch down in size to insert it.

[@bastienx8]

Just putting a hot air blower or halogen lamp at the entry is not very energy efficient, for a process that takes hours this is something to consider

[@sementhrower420]

Off topic, but I think you might be the right person to ask this, if you don't mind helping out a random internet stranger :D I'm working on creating coaxial nylon-nichrome wires where I want to embed a nichrome wire in the core of a nylon monofilament line. The ultimate goal is to achieve this with 0.1mm D nylon and 0.01mm D nichrome wire, but I'll first try to do it with larger D nylon. What Stephan built here is roughly what I am also planning on doing, and in addition also feeding the nichrome wire through the core of the nozzle. Do you think this would be workable and do you have any tips? Thanks in advance!

[@lescarneiro]

This TPU core experiment is just GENIUS! That's why I love your channel, you do science with your experiments, not just funny things for likes and subs

[@danilolattaro]

Absolutely genius!

[@zackj997]

Why a solid core instead of the TPU and PLA emulsified together? People already use silk PLA for flexibility in certain applications since it already has TPU in it.

[@rich1051414]

@@zackj997 The solid core unmixed turns it into a composite. When you have two materials with different properties together, their strengths can add together in ways that wouldn't if they were thoroughly mixed. In this case, the flexibility of the TPU functions like dampening rebar, preventing fracture propagation while preserving the stiffness that PLA offers.

[@ronnetgrazer362]

@@zackj997 Really? Most of my silk prints seem more brittle, not less. I'm a sucker for off-brand budget filament deals so that might be a factor.

[@kbee225]

It sounds genius if you know very little polymer science. PU and PLA are not chemically similar so they form what we call non-compatible blends. These blends are basically those that cause boundary layer separation because the two materials are not chemically bonding with each other, this forms a weak material that is worse in most aspects than the homopolymers themself. This is why when making polymers blends with dissimilar materials we use compatibilizers to act as a glue and bind both the materials together.

[@ac281201]

4:13 This phenomenon is actually a result of two combined effects: necking and strain hardening. When tension is applied to the nylon filament, it begins to undergo plastic deformation at its weaker points, leading to a reduction in diameter. At the same time, the nylon string strengthens in these areas of reduced thickness, which concentrates the strain on the thicker segments of the string. The combination of these effects causes the string to shrink to a new, constant diameter before ultimately breaking. Articles for more information: en.wikipedia.org/wiki/Necking_(engineering) en.wikipedia.org/wiki/Work_hardening

[@miqo85]

aka continuous necking

[@hugofernandez8522]

It's kind of right but not quite, the effect is due to the majority of the chains in the polimer getting aligned and because all the chains are in the same orientation they become stronger

[@hugofernandez8522]

In amorfous materials like polymers you don't have strain hardening like in metallic materials

[@ac281201]

@@hugofernandez8522 Yes, you are correct, in the case of polymers this effect is the result of chain alignment and not crystal shifts like in metals, but still, this effect is called strain hardening (or work hardening) in both cases

[@louisvaught2495]

As others have mentioned, this is not work hardening, it's chain alignment. No, they are not the same thing. Work hardening is a crystallographic behavior (polymers do have crystal structure) while chain alignment is just generally the idea that you can do things to the material that cause the long molecules to be oriented in roughly the same direction. Chain alignment doesn't require work-hardening because polymers are viscous and have huge molecules. Things like melt-spinning can also cause higher chain alignment. Chain alignment also doesn't have to interact with the crystal structure of the plastic, and happens even in amorphous materials. It's just about the average direction the polymer chains are oriented.

[@tomallo99]

That's insane, really, creathing a visible logo INSIDE of a filament spool, with hardware that's DIY and accessible to a hobbyist? Man, you just keep on delivering bangers, your ingenuity is amazing

[@XVRickXV]

You could think of the TPU as muscle and the PLA as bone and have them switch places. The tpu absorbing more impact on the outside and the PLA receiving less shock because of being shielded by the flexible TPU the same way that flesh protects bones most of the time. Awesome experiment!

[@lickytime9683]

The outside of the filament would also be bending more than the core, so having the outside made of tpu must be beneficial too

[@cfeigel]

The WInFiDEL sensor lets you measure filament diameter. Now you can implement a PID loop to automatically figure out the proper temperature at a given speed. If you want faster production, turn up the speed and the PID should correct for the change.

[@AndrewAHayes]

This is why I love this channel, most of the other channels I used to watch are either all doing Voron builds or reviewing the same printer that's been done a hundred times already. This channel is unique!

[@cmbaz1140]

I think 3d printer experts should learn more from candy makers...the more i learn the more i am convinced...

[@not2unknown1]

A PLA core with a water soluble PVA mantle could create interesting structures or grids when you print it and put it in water. Kind of like how aerogel is made, but bigger.

[@ziocrielo6148]

3d printed sponge lol

[@paulpoleon8570]

Aero light plastic for rc plane wings or something

[@ericbuchner2982]

Unfortunately with the constant cross-section shown in the video I don't think this would give useable results. The core never bonds to itself, so if you dissolved the outer layer the entire print would just fall apart. It might work if you could vary the cross-section so the core sticks out in places, but that would be much harder to get working.

[@markswayne6326]

If you printed it with stripes of PVA that are diagonal edge to edge but left solid PLA layers between, the PVA might be able to dissolve out while leaving behind a structure that wouldn’t come apart.

[@MarcStollmeyer]

Embedding your logo in the filament is such a flex and extra way of tagging your prints as genuine.

[@capslfern2555]

I love that, watermarked 3D prints

[@lucianoag999]

Except that everyone can do it.

[@greenboy3d]

What a coincidence that we both made a video about mixing TPU with PLA at the same time hahaha 😅 But I was a bit faster 🙃

[@Craftlngo]

Upvote for more awareness. Your idea to mount a corkscrew extruder on a 3D printer could be a real game changer!

[@mr.shplorb662]

Not to brag or anything

[@csforesman]

Wow. So glad I saw this comment and went to check out your channel. As cool as the idea in this CNC kitchen video is (and no slight to Stefan, this really is a great idea), I think your pellet extruder has way more potential to revolutionize 3d printing. Amazing work.

[@Nachtschicht1]

I've recently seen your video about that and I think you deserve a lot more attention. What would you think about about combining your idea of direct printing from pellets with Stephan's filament-extruder and Thomas' thickness-sensor to regulate the speed of the extruder to match the amount of filament that the printer needs to build a printer which makes its own filament on the fly? That would solve the problems with the much heavier printhead and reduced printing-quality.

[@greenboy3d]

I think this idea might work, there are also ideas like implementing a real-time pressure sensor or AI camera to measure the flow and to automatically adjust it in real time. The only thing that needs to be done is the research & development which is costly and since I have spent most of my savings on R&D for the extruder itself... For this reason I keep all these things in mind but for now focus on releasing the extruder so everyone can benefit from it... 🙂

[@loganluckless372]

I work at a company called Hills inc. where we do cross section logo fibers and other wild multi extrusion projects. Cross section logo fibers like that are used a decent amount in industry by basically making a dot matrix on the core of each fiber and routing the colored polymer to it's place in the matrix.

[@janbeck8269]

How about filaments with an embedded cf or Kevlar strand. Is that done?

[@Kronash]

used work in a factory making plastics. the speed of the puller is Very important for final dimensions

[@lukesmith9059]

I would love to see more videos on metamaterials! If the stiffness of the tpu-pla is close to normal pla it would truly be the king of all printing materials for parts that don't need high temperature resistance.

[@thomasmascitelli5159]

I love material science. The phenomena where the filament shrinks under tension is called "necking"

[@TurboSunShine]

Oh god i was so young back then... excellent technique! love the 4mm to 1.75 downsizing!

[@Deveyus]

I could imagine some tweaked slicer settings to optimize the use of these properties yielding some fantastic results.

[@kylebuffington7673]

So many new ideas continue to pop up in 3D printing. Non-planar printing, arc overhangs, and now you are showing off multi-material filaments. Ten years from now, 3D printing is going to be absolutely off the charts.

[@RolandKnall]

This is just crazy and unbelievable cool! I think Filament recycling will become more affordable quite soon as a side-effect of more and more such videos popping up. But in any case, as an Austrian: saugeile Technik!

[@FTBT3D]

That TPU/PLA is so cool! what a great experiment

[@antirez]

Doing material research at home with cheap equipment and just an insane amount of smartness and dedication? Very cool.

[@Avets610]

Always pushing the limits of 3d printing, great job. The watermark filament honestly blew my mind.

[@MatrixRay19]

Why not PLA core TPU shell?

[@sephrosemary]

Imagine finding a way to embed continious carbon fiber in a filament this way!

[@UnCoolDad]

This exists already in the high end commercial printer world.

[@olafschermann1592]

Yeah, thats the way! And opensource it

[@thenextlayer]

As always, you're living in the year 3,000, and the rest of us are just trying to catch up. I don't know how you come up with these ideas, but keep it up :)

[@skelliton_67]

The nylon string reducing in diameter when tensile force is applied is called "necking". I got this definition from google, "In engineering and materials science, necking is a mode of tensile deformation where relatively large amounts of strain localize disproportionately in a small region of the material. The resulting prominent decrease in local cross-sectional area provides the basis for the name neck."

[@JakeWitmer]

Can this be modeled in a bottom-up simulation?

[@aymericbiancopelle1149]

TPU + PLA looks like forbidden candy

[@startedtech]

If its ever sold that TPU/PLA combo should be named Wagyu beef!

[@Dwonis]

Having a flexible core and a hard surface is what makes teeth so tough... so it could be called Wagyu Teeth! 😂

[@martinsmith2948]

Once again he has changed the 3D printing world

[@peterkiss1204]

I would drill that nozzle up to at least 1,8-1,9mm and pull the filament at above the breakpoint of the diameter/pulling force curve to achieve correct diameter and fuse the layers together properly. Also a loadcell controlled motor driver circuit would help keeping the pulling force constant.

[@ZeFoxii]

For the layer adhesion issues why not pull it twice once to get the diameter and then again at a higher speed and hotter temp just to make sure it fused together.

[@thomasleftwite]

You are a pioneer in expanding the possibilities for 3D printer users.

[@thetheflyinghawaiian]

I was just watching that artisan candy stretching youtube before this was suggested to me, similar concept in some ways!

[@umikaliprivate]

I dare you to print on a regular fdm 3D printer using solder. I mean it would be liquid af, but if you could cool it fast enough, this could be revolutionary.

[@richardmillhousenixon]

Solder melts significantly hotter than FDM filament, it's not really that feasible

[@umikaliprivate]

@@richardmillhousenixon I actually tried this, and it did seem to melt, but I wasn't able to find solder with a diameter of 1.75mm, or anything close to that, and my printer had it's extruder not attached to the print head, so I never got anywhere with it.

[@yzkn8848]

for anyone who is willing to make a cursed filament, lemme give you a idea. LW Any material outside and any carbon fiber filament in the core or tpu in the core. not only this will make LW prints more stiff or flexible depending on application, it will make them more durable too while maintaining LW properties. Thank me later

[@SamChaneyProductions]

This is one of the coolest advancements in consumer 3D printing tech I've seen in a long time. What a great innovation. Even as a mechanical engineer I'm a little surprised how well you got this to work with such a simple setup, especially getting such disparate polymers into a single filament!

[@ferrumignis]

Rather than pulling the filament through the nozzle, I suspect a 3mm extruder pushing it into the nozzle is going to be faster and give much more repeatable diameter.

[@jkachele]

Hexagons are the best-agons! CGP Grey Reference!!!

[@GinoTubaro]

Abs outside, pva or any other soluble material inside could be a crazy tubing situation worth to research!

[@TheToelle]

A CNC-Kitchen Video 🎉 my Evening is saved.. Why my evening? Because each one of them teaches me enough to continue reading for hours… thank you!

[@dummypg6129]

hmm would it be possible to get a very thin magnetic wires as core material for meta filament?... so basically print the 4mm with hollow core, then when extruding to 1.7mm add the wires? this could be a nice electronics application...

[@sleeptyper]

I have an idea. Make the filament have a clear core with transparent coloured shell, print a cool vase model on vase mode and find a way to send light thru the extruded filament. Maybe one of those 60mm LED pucks from eBay under the vase would do it. On the other hand, a black core with transparent shell could be very interesting as well.

[@properprinting]

Man, this is genius! The most interesting use case I've seen for the Prusa XL and this really inspires!

[@martinsmith2948]

Babe wake up! CNC Kitchen just uploaded

[@jercki72]

4:25 I remember something like this, a quick google search tells me it's called "necking". Don't remember that term but on the tensile strength curve it's the part where force stops increasing with deformation due to the section becoming smaller.

[@maxlott4029]

Thanks

[@arcrad]

Dude you are the GOAT of 3d printing experiments. Is there anyone else out there doing stuff as cool?

[@zootsuitpenguin]

Added a like as ‘Hexagons are the Bestagons’

[@ChrisHarmon1]

The wilder the hair gets, the better the engineering?

[@PaulDominguez]

How about PETG with a TPU core since those materials bind better

[@ouansungyidan]

Omg he made his own metamaterial at home. Kind of freaking out right now. That's a research gold mine.

[@louisvaught2495]

It's not particularly useful due to the high shear during production. That imparts unfavorable structure on the material.

[@ouansungyidan]

@louisvaught2495 That's a great point, the production method can be improved. But the concept is still amazing. Hobbyist accessible metamaterials. That's still got me excited.

[@louisvaught2495]

@@ouansungyidan You can work a bit to remove the molecular alignment, but in general the process being used to *make* the structure is what limits the final properties. This particular process being so accessible and macro-scale means you don't have much molecular control over what's coming out. The part of the video where Stefan discusses having to keep the filament from getting too soft is a great indication that the process is really dependent on the molecular order of the polymer, rather than the process having any control over it.

[@epilepsianfall]

Try the opposite, TPU with a stiff PLA core for strength. Might give you a strong "skeleton" to the floppy TPU.

[@DrakeTain]

Now that is neat.

[@MooreAnalytical]

Seems like you need some post processing to keep the filament from delaminating. You think you could print in a heated chamber with the Prussia XL?

[@TheOneAndOnlySatan]

And again Stephan changed the 3D printing world again! What a legend!

[@That_Gunner560]

If you printed a small tube blank and manually ran a thread of carbon fiber or fiberglass through it, could you make FRP prints?

[@luke_fabis]

I wonder if this method could be used to make weird composites like Kai Parthy's experimental filaments from ~8 years ago, but in a more controlled manner. Say you could lay a bead of PVA or HIPS inside of a different filament to make printable capillaries. Or if you took an expanding filament like varioShore TPU and embedded it inside the same material without a blowing agent (plain old TPU in this example). Another possibility might be to include to take several materials that are chemically related, melt at similar temperatures, and are known to bond well, but which have substantially different properties. Like PETG, Hytrel, Arnitel, and other copolyesters. Or perhaps PLA and PHB. There might be an opportunity to start experimenting with 3D printed fiber optics, or at least crude light pipes, by embedding clear material inside opaque. In a similar vein, a strand of shape memory TPU embedded inside of a softer, more elastic TPU might have some interesting properties. One final idea. Existing composite filaments might be happier to bond together than plain virgin plastic. For example, PLA and TPU don't like to bond, but what about CF-PLA and CF-TPU? If you could coax the carbon fibers to tangle up or even migrate between layers, you might get much better bonding.

[@r2c3po2]

Never done any 3d printing myself and so I am approaching this from a point of pure ignorance, but is there a different material that mixes better with both TPU and PLA, which could act as a buffer for better adhesion?

[@sebastiendine4834]

What about extruding a thin copper wire within a pla filament? I am not sure how it would behave inside the extruder of the 3D printer. You could try with other metal wires. I think a 0.5mm or .25mm diameter copper wire could work. It could be useful to stiffen the 3D printed parts or add some electromagnetic properties (shielding, polarization, meta-material) or make coils? You could create some strongly anisotropic electromagnetic properties due to the intrinsic layer structure of the 3D printed parts.

[@Eric_In_SF]

It’s actually 3 phenomena Necking: Localized thinning and formation of a narrow region that can propagate. Cold Drawing: Stretching that aligns polymer chains and reduces diameter in a wave-like manner. Viscoelastic Behavior: Combined elastic and viscous response leading to slow deformation.

[@jan_harald]

I think one interesting way to use this, is with multi-extrusion/dual-nozzle printers, themselves, printing a multi-layer spool as the nozzles are fixed, extruding from both, would mean the base printed spool would already have a changing pattern when printed with, but also, it should probably help with metamaterials, as you can have each material as their own perfect temp, without letting the other material cool down, both the changing position, not being in perfectly straight layers, and having both of them be hot while laid down, should greatly decrease the risk of delaminating, imho

[@CatMan36]

4:27 The phenomenon is based on the crystallization of thermoplastics. To summarize: when a thermoplastic is pulled apart, the polymer chains in it lie next to each other, making the thermoplastic stronger, as more intermolecular attractive forces can be formed. As a result the crystalline part of the thermoplastic isn‘t pulled apart, but the weaker non-stretched gets stretched. Have a look here: de.wikipedia.org/wiki/Kristallisation_(Polymer)

[@xankersmith9194]

You should try putting the Winfidel sensor in the feedback loop of an automatic controller for detecting filament thickness. It could actually be accurate compared with the pulling-a-paper-clip-and-hoping method.

[@gustavoheck2378]

I think you should try TPU with a core of PETG for printing airless basketballs. So the TPU would get the perfect layer adhesion, while the PETG would make it bounce

[@elongatedmuskrat5170]

This effect is called necking. It comes from the alignment of polymer chains. The modulus of elasticity of the material also greatly increases when necking occurs as the aligned chains creates higher crystallinity. This can also occur in multiple steps of necking down the diameter until the stress required to force the diameter down via aligning the chains further is greater than the yield stress of the filament at that point. PS: as a polymer engineering student, i love your videos.

[@CrassKitten124]

Such a cool concept! I wonder if you could print the pulled TPU-core filament into a second 4mm blank, and then repeat the pulling process to get even smaller TPU fibers

[@WillPower311]

I know when they do aluminum extrusions they stepped down sizes gradually so if you were going from 3 mm to say 2.5mm to 2.mm to 1.75mm would be easier on the filament

[@jamesalewis]

4:19 the phenomenon is called "necking" most commonly, at least when considering metallic materials, but I see no reason a new term should be invented for polymers.

[@jessicarussell2712]

Put copper wire in it to make 3d printed coils for motors use the plastic bottles that makes a tube to thred the wire through while extruding on your filament making machine

[@ReassuredPrimrose]

mabye resize it in 2 steps, with the final one being much hotter but like 2 mm to the 1.75mm. this could help the bonding problem

[@RooMan93]

Imagine having a binary stream of conductive or IR sensitive filament inside and it becoming a type of DRM.

[@briannewman6216]

Composite filaments could be used to significantly improve the mechanical properties of FDM printed objects.

[@coleabbott3432]

You should use the tpu core pla to try and print one of those 3d printed basketballs. Everyone complains pla is too stiff, and tpu is too soft.

[@domkri9502]

Every time you publish a Video it takes two days and your content is featured by all the 3D printing/ Maker Websites, this is amazing. Thanks for your R&D work and making it open to use for everyone Danke 🎉

[@xilw3r]

The effect of diameter reducing under tension is called necking

[@Souliset]

weave it like a multicolored rope before pulling it

[@jellevandergraaf9303]

I believe the thinning phenomena that occurs when pulling polymers like TPU is called "necking"

[@lincolnsiebelink6628]

make a carbon fiver core around nylon and rig a servo with a razor to cut it off each time you lift the print head.

[@deliziosetiefkuhlkost2463]

Please do a dedicated video about the strength and toughness of some filament combinations. I am definitely interested in the mechanical properties and think that it could lead to some promising future filaments

[@LeFranzMan]

Mixing the materials (PLA+TPU) is cool, but limits the recyclability :(

[@cbpcbpcbp]

Use the multicoulered matirial to print a fillament for recising and you will get an amazing fillament

[@CaptainSlug]

Wait, if tricolor PLA were used through one of those experimental printers with a rotational axis extruder you could setup the slicer to change the rotational position of the extruder during printing in order to change and vary which color is visible on the outside of the print. This would actually allow you to print out those FEA models in full representative color. You would however have little or no control of the color output for dithering purposes beyond the available color gradient in the filament itself. Orientation would only allow you to control the portion of the filament that's shown on the outside of the part. So filament color blends with high contrast might allow for some in-model color variation without having to do any of the filament changes that a multi-material setup would otherwise need to perform to switch colors. Purge towers or other inbetween-material purge methods would no longer be required for switching colors. The major hurdles to the above would be setting up the slicer to understand how the rotation relates to the colors available, and more complicated from the hardware/firmware side would be the need to monitor the orientation of the filament color itself as it either enters or exits the extruder. It would be a very challenging but unique project.

[@JonS]

Really interesting work. This opens up a lot of new possibilities. Although maybe not as much as your new mathematics at 11:51 (four halves) 😂

[@Doile911]

9:08, No, but 3mm filament is usually cheaper, since its not as widely used.

[@Markfps]

What a crazy idea PLA + TPU core, amazing job man! This is surely a neat improvement for prints that will face a lot of physical stress

[@cfeigel]

I think your PLA with TPU inside needs a core of carbon fiber inside that.

[@-Xaverius]

This is reminiscent of the process which is used by candymakers to create pattern in hard candy

[@PLr1c3r]

There's so many interesting possibilities mixing different materials within one extrusion. This is definitely one of those ah-ha moments for the technology. CF Nylon with TPU or ASA with TPU could make interesting case studies. Delving further in mixing multiple materials to harness more properties is another product of these types of explorations. GJ Stefan always keeping us on our toes!

[@erokfussell]

A couple of weeks ago I printed a TPU/PETG filament. It worked great for the printable balls! Improved bounce compared to TPU and much more durable than PETG.

[@JD2jr.]

I feel like you should have an extruder on that nozzle that pushes the filament through at an equal rate (volume/time) as the spool so you can really melt the stuff together and just spool it instead of actually stretching it.

[@JD2jr.]

Could also try stepping the size down more slowly, do 3>2.25 and then 2.25>1.75 or something. I would think a smaller change would also result in less inconsistency.

[@forrestliew]

Instead of pulling the filament from the nozzle, maybe you can try pushing it through like how a 3D printer normally works?

[@Bdcrock]

Bro has discovered common sense congrats you’re smarter than this guy when it comes to this type of common sense you should be proud

[@evilratchet777]

Extrusion process engineer here. The phenomenon where you can stretch hot plastic is known as "drawdown." That's also the name of the process you are using. The simple explanation is that this phenomenon occurs due to internal tensions pulling material from the "corners" of the part to fill in the middle, where the material is splitting under tension. It helps to visualize it as a continuous landslide from the hilltops into a valley that keeps growing longer. You can also get something known as "die swell" as plastic expands due to the pressure drop at the die openings. Die swell isn't really something we have to consider with 3d printers, but it should be considered if you are extruding filament with an Archimedes type extruder. As for your filament layer bonding problems, you may be able to solve that by preheating the filament before drawing it down. Also try over-extruding your print by 3-5%, this should help layer bondability. Also, tension is everything. Pre-tensioning will help both the bondability, and help keep the filament from rotating during drawdown. The more aligned and balanced the tension is on either side of the nozzle, the more consistent the final filament turns out. Good luck, and keep up the amazing videos! "Like everything else in life, 3d printing is just a primitive, degenerate form of extruding." -Bender

[@WF3D]

Absolutely insane engineering! Great Idea! The PLA TPU could be great to make bouncy stuff I guess? Stiffness of PLA combined with inner flexibility 😮 What about an inlay of PVA in PLA? You could have really tiny channels in every layer creating a sponge like material 🤔

[@jonathan3518]

4:28 Necking. When it draws to a smaller diameter it is called necking.

[@supercurioTube]

This is absolutely amazing, I'm so impressed with what you came up with, so creative and well engineered at the same time. You ended on what you would try differently after exploring the reforming method and I can't wait for the next step.

[@donaldburkhard7932]

Can you mix a hard center soft outside to use for prosthetic hands?

[@klazzera]

the phenomenon is yielding and chain alignment. when it stretches to the point that polymer chains are fully aligned, it reaches a higher modulus and strength and stops being the weak point so the thicker sections continue to stretch