Why Machines That Bend Are Better 

Weird flex but okay

As a former student of mechanical engineering I feel like this is the real business. 3D printing is a pretty cool addition to the toolbox but going back and rethinking linkage mechanisms in this way feels way, way more exciting and fruitful to me.

Professor Howell: "Here's my book, it's the most cited book in the field." He's flexing.

I work in an R&D lab of a Swiss watchmaking company, and I can tell you that compliant mechanisms are currently by far the hottest topic in research for mechanical watches. For example, they're used in the form of microfabricated oscillatorsmade of Silicon in the Frederique Constant Monolithic and the Zenith Defy Lab.

11:27 "So are these now being used on nuclear weapons?" "You know, it turns out they don't tell us" Now I know how to take my resume to the next level.

The clutch is actually a centrifugal clutch, exactly like the ones in the chainsaw, but the one in chainsaw have 2 or 3 springs, and those springs break all the time. So these parts would be much more efficient since they’re made out of one piece. Nice!

Such a good vid. You don’t get a sense for how they feel from the video. That’s the only disappointment. Why no haptics, Derek??

I used a chainsaw quite a bit and let me tell you I would've been saved a few headaches if the clutch had been a single compliant mechanism instead of the mess of metal and springs that it is. That is an amazing practical application for this.

This is amazing. As a mechanical engineering student, we are learning all the ways to prevent bending and shear, whilst you guys are taking advantage of it to make advanced mechanisms.

Larry is like literally a clone of my uncle and my grandfather. All engineers, same gestures same glasses the same clothes same hair

Before I retired in 2009, I was talking with an associate in our testing lab that had worked on the safety and arming mechanisms on a particular nuke, in the conversation I asked about the high order of electronics that must be in those devices, to the contrary he said very simple mechanics and simple electric devices are used to keep reliability high.

The fact that they physically have to interact with it on a microscopic level for it to work is amazing

My new favourite video from you Derek!

How cool is that! Actually most materials recover very fast from bending force, where you don't have fatigue or plastic deformation involved. The trick is to design for instance a tool where you can control the direction of the forces involved. If the tool is used as it supposed to be used it can almost last forever. Design and control the forces to work in the right direction and then make sure the design is used correctly. Nice...

I could totally see the plastic vise grips being used as some sort of pliers suitable for cleanroom use

Always great when you can use Veritasium as a source in essays and stuff. Doing a 1st year eng research essay on the possible application of Compliant mechanisms in landing gear for spacecraft. (due in 3 hours as of writing this[almost done]) It is so nice to be able to watch a video and then understand(at least a vague understanding) of what all the papers I'm reading are actually saying. Edit: got an extension, now I can expand my conclusion paragraph

This man-made me to change my major from biochemistry to engineering. I just want to thank you for your inspirational video that kept me going to do things I love everyday.

The thruster control module was probably the coolest thing I've seen all year.

I love how he genuinely just loves his mechanisms, he looks like a kid with his favorite toy. The best way to be.

Another key factor for the increase in precision besides the elimination of play (backlash) is due to friction being almost eliminated. This eliminates hysteris, also known as virtual play. The precision error of a mechanism is the sum of its play and the virtual play components. I think that including some simple force/distance diagrams would have helped alot for understanding these concepts.

This is pretty cool, makes sense for some applications. My major concern would be stress and fatigue issues, of which they are obviously aware, and for which they have done some testing.

Muito obrigado! Excelente vídeo, e agradeço também por estar disponível com legendas em português...

Thanks to incredible people such as Professor Howell we as a species can evolve and get better. Science is amazing

That man was such good sport. Very open with how it works. I personally thank him for being on this episode

I love this guy, he's so nonchalant about mind bending engineering feats.

That could be great in aerospace. Imagine a wing with adaptive flaps that just give you more lift at lower speed through movement by the speed itself.

Amazingly efficient and impressive. The possibilities at the quantum level have suddenly come into perspective. Good video!

I wonder how amazing yet simple those things are! How come anybody couldn't figure this out before?

This guy and his work should be in school books! He is the definition of thinking outside the box.

Please, just pause for a moment and reflect on the fact that the phrase "3D-printed titanium" is, in fact, an ACTUAL THING. That is freakin' awesome... what a time to be alive!

This is absolutely amazing! Thank you for bringing this to our attention!

I agree with similar comments that this topic intrigued me like no other. It is almost like modeling an exoskeleton but in a future modernistic manner. This seems like future tech that is so cool that it has come back in time for us mere mortals to marvel over.

I was mind blown by the first titanium hinge. My jaw legitimately dropped, and I’ve only done that 3 times before in my 21 years of life.

Pretty cool. I would have liked to hear about it's limitations right now as well.

Smaller part count is potentially useful for manufacturing but for longevity it would mean having to replace the entire thing after any operational failure

That thruster control for the satellite is a thing of beauty. I'd love to see an animation of how it works!

It would be amazing if they made a Compliant mechanisms for slingshots or cross bows.

This should be part of every mechanical engineering education.

I really loved the idea of these machines and this type of mechanisms seriously need to be used more...thank you for the enlightenment.

Why can't we have professors like Dr. Larry Howell? Life sucks

I would have loved him as a professor! If I had the opportunity to switch to compliant mechanisms for my speciality, I definitely would.

This is honestly one of, if not the best video you've made. Was great to learn so much about a topic I didn't even know existed.

My dad was a professor at BYU. We lived in a neighborhood that had a lot of engineers and scientists that were notable but humble like this guy. It’s one of the reasons I went to BYU.

Love the use of compliant mechanisms! Great work guys, soon we will 3D print a glass compliant mechanism :O

The extrusion process sounds very cheap for some parts. I'm very impressed. I've worked with a few items made like this and I had concerns about the part wearing out prematurely. However, my concerns have been eliminated. The once-piece clutch was very nice.

The only thing I'm concerned with is the breakage due to fatigue in the 'bendy' zones. If that is not a problem then I'm sold on the idea.

This is crazy good. Opens the door for my brain to think of many cool mechanisms that I did not think of before. Really awesome. Thank you so much!

_Any machine is flexible if you're just strong enough_

You, your team, and all the people that you feature are so very talented. thank you for sharing as always brother

Love that you and PhysicsGirl are friends! Also super proud of myself when, while watching Harry Potter, I realized what Veritasium means! Love this channel. Keep up the amazing work. I teach STEAM in elementary and my students benefit from my learning from you.

Professor Howell's patents must be quite lucrative to BYU. This video could have been 3 hours long and kept me engaged.

very cool. I would be interested in knowing more on the life cycle of the micro switches. Silicon!? Bet they are great at static, interested in knowing how to combat hi-Vibe!

My professor made a lot of components for electrical devices... feeling lucky to be learning with him! Mechanics of Materials

"you would scream in pain " *puts his finger and then scream * they don't call him a scientist for nothing bud

"machines that bend are better" Bender: "shut up baby, i know it."

This is so cool. Compliant mechanisms really take advantage of the elastic deformation in materials.

In 1968 I did research to try to put a machine, a molecular beam, on a glass slide, that could then be rotated to get three way velocity specification. The microchip etching needed had not yet been invented (I tried to use asphalt and HF). But there were mechanical components too. These kind of etchable devices could serve for controls. So far as I know, the device has never been made or researched. Maybe it's time to try again using these advanced mechanisms.

I have a pet peeve with battery compartment covers on remotes and other small battery powered devices. They can be hard to operate and quickly fail. My favorite is a compliant U-shape latch that always works easily and never fails!

This is awesome! The implications for chip tech are huge. Well actually huge for everything.

A video about 3D printable nanomachines is, somehow, focused on nuclear weapons and sponsored by home security. It's both exciting and very terrifying.

The professor is so humble , i like it

I legit used to think of this concept and was wondering if there was an actual term for it and now I've come across this video.

Centrifugal Clutch on my old go cart (driven wheel) had a cylindrical aluminum housing. Driving through the woods one day, caught a branch in the chain sprocket. I surmised turning the wheel in reverse could free it, but more leverage if I could spin the clutch body & sprocket to release the branch. My bare thumb & fore-finger slid off the clutch housing with a sizzle, so fast that it didn’t hurt, but the white char endured for a while (no scar remained), but lesson learned.

I had two garlic mincers in my life. One was not bendable metal that my mother bought in 1978 and one was a bendable plastic one I got in 2012. I still use my sturdy metal mincer that is older than me because the plastic one broke within 5 days.

In the military we use a lot of carbiners [sic] and S clips and about 2007 they changed from using springs to bendy part to be a piece of steel with offset connection to the solid bit.

Dr. Howell is an amazing Professor and a great guy. I was lucky enough to take his compliant mechanisms class. I'd highly recommend reading his book and learning about how to design compliant mechanisms using pseudo-rigid-body models. That's when your mind will really be blown! To think that we can take complex mechanical systems and make them compliant using a simple formula is what is really quite amazing. Great video!

Really cool! The metals have an initial elastic deformation, which allows them to revert back to their original shape. As long as the devices printed do not go into plastic deformation, it would work really well for a very long time. So brittle materials like glass and ceramics become extremely difficult to work with in these applications. Thanks for the video.

Very cool and inspiring. Time to get to the CAD and make something amazing.🤖

That clutch design could improve so many designs. One part that can be swapped instead of annoying mechanisms would save time and money!

I've seen plastic mesh tires that seem to benefit from this principle. Next step, of course, would be similar suspenison... If you can control to such a degree what movements are allowed, this could save a lot of weight.

This really calls for much respect for this research group and Professor

Practical examples of use of compliant mechanisms in everyday products 1. Every shampoo bottle uses a live hinge made by injection molding - very cheap, durable and assembly free. 2. Computer mouse buttons use flexures (those bendy things you see throughout the video). The microswitch inside it has a diaphragm flexure and the top casing flexes when you press on it to transmit the compressive force. Older mouse models had separate distinguishable buttons, now its all one piece. 3. Cable ties have a very small tooth with a flexure that engages a rack. You can often reuse cable ties by disengaging the tooth from the rack using a pin and pull out the rack while holding tooth off the rack with the pin. 4. All plastic components of every product you use has a snap fit for assembly - no requirement of fasteners. 5. Every book uses live hinges (crease where you bend) for opening and closing. 6. Some cheap click type ball point pen (e.g. Bic retractable pen) uses flexures to keep the extended pen nib in its position. 7. Tic tac box uses living hinge for the lid. 8. Volume rockers on your cell phone uses flexures instead of springs to bounce back 9. If you have a wind up pendulum clock, the pendulum is suspended by a flexure for avoiding friction caused by use of a pivot. 10. Snap fit locks for straps in duffle bags/backpacks etc. 11. Some shot microphone mounts uses flexures for vibration isolation. 12. Camera lens covers uses flexures for springs for holding the cover on the lens. 13. Disposable food containers, clamps for IV lines. 14. Paper clips. 15. Foldable plastic forks found in ready to eat noodles have a living hinge in the middle for folding. 16. Leaf springs in vehicle suspension (Thanks to Heartycoffee in the comments for suggestion). 17. Tweezers and forceps (Thanks to randal gibbons in the comments for suggestion) 18. Safety pins (Thanks to DrBrainSol in the comments for suggestion) 19. Accordion-style toilet plunger (Thanks to Gary Young in the comments for suggestion) p.s. I will add more to the list later. I love flexures and thank Derek for making a video on compliant mechanisms with Dr.Howell

I was thinking of making something similar to the NASA thruster joint shown here as my final Engg. Paper even though I'm a second year Mech. Student but this inspired me alot . Thanks Alot ❤️

Normal people : Any machine is flexible if you are strong enough. Engineers: Any machine is flexible if you are smart enough.

Amazing video! I love the innovations insanely smart people come up with!!

Of all your videos this has me perplexed the most. Funny thing, back in my university days studying engineering, compliance’s where everyone’s enemy of precision. Even worse, bending components like the one you show were a BIG no-no because of premature failure due to material fatigue. To further the point,knuckles and joints are the preferred way of nature (look at animal kinematic). To say that this actually works is a very bold thing.

You sometimes feel things like these were already made… I had this in mind years ago how the centrifugal force could be used in a clutch and turns out, it wasn’t really being used until now. The problem with new ideas is, you do not know if they are already being researched upon or not… So simple yet so sophisticated.. its so cool to watch such innovations!

This is mind-bending, but luckily, my mind is flexible and compliant.

I used the mechanism shown at 6 minutes in to make a patent application in my former company. We printed this particular geometry from the video to show off the principle.

seeing Diana made me want to cry, shes in such a hard place right now and just seeing her being so happy makes you realise how unfair this world is

FASCINATING! In slow motion some of these components are still deceptively clever. Modeling the 'snap' point of such materials must be complicated, to the point that trying different materials, widths, and angles are no doubt exhaustively checked during prototyping.

very cool. informative and entertaining. but what im most impressed with is how easily you can keep a clean shot/frame without looking.

The Thrusters titanium inputs look fairly similar to the same mechanism that controls the joysticks on remote controllers!

8 P's 1.) Part Count (Less) 2:42 2.) Production Processes (Various) 3:28 3.) Price (Inexpensive) 3:33 4.) Precise Motion (no backlash) 5:21 5.) Performance (no backlash) 5:38 6.) Proportions (smaller) 7:18 7.) Portable (lightweight, space application) 7:33 8.) Predictability (safing & arming WMDs) 10:17 in case you missed them :)

Unmentioned but this seems perfect for robotics too, as an intermezzo step towards the so very complicated tensegrity-type tendon-based musculoskeletal systems.

my grandfather worked for Boeing in Seattle as an engineer and was then invited to work at NASA from early 1960's until his retired, he would love this channel!

Also known as living hinges or built to fail devices for mass production, however in some situations they are a great solution

Imagine letting AI experiment on compliant mechanisms and the infinite possibilities we have not thought of yet. Once we let AI run our world (this will happen in a matter of 50-100 years btw), it will accelerate humanity to levels beyond our imagination.

I had a complain mechanism class last year during my Bachelor in Microtechnic at EPFL, and I loved it!

I am stunned by this level of mechanical and dynamical precision.

I am not an engineer, but I have dealt with them, and Larry Howell fits the stereotype perfectly. Dilbert comes to mind.

Respect to this professor

the mechanism at 10:44 reminds me of the way a bulova accutron works (analog to a balance spring.).there is a tuning fork which vibrates with 360Hz. this is transformed to a gear with 300 teeth and makes it turn 1,2 times per second as a time base. you can hear the watch humming with that frequency.

More fascinating machines. Even some that just make peculiar sounds but I couldn't see what their function was apart from that. Perhaps this could lead to inventing new kinds of musical instruments or at least different percussion or sound effects !

i would want a more detail of this. this seems quite interesting

That prof looks so humble. All engineering profs should be this cool.

another advantage is that because there are less moving parts they’re more reliable

I find it really hard to believe that those tiny plastic parts (the parts in the demo models that actually bend) are more stable and longer lasting than a traditional bearing + axle. All plastic stuff I know of that was tried to replace "expensive" metal hinges/bearings broke after short time. And how about metal fatigue (don't know the proper word - it is the phenomenom that metal that is bent frequently changes its inner structure and becomes sort of brittle and weakens over time) - isn't this effect setting in faster than when using traditional (again) bearing + axle?

Absolutely love it. The medical applications will be tremendous.

It looks cool, but I'm not entirely certain about the benefits. For one there's a big difference in replacing a single standardized nut or a whole unique mechanism. Another point would be the strength of those flexible parts under unexpected loads. But I expect the ones in charge of product design to take such factors into account at least to some extent.