Why Machines That Bend Are Better

  • Published on Mar 12, 2019
  • Compliant mechanisms have lots of advantages over traditional devices. SimpliSafe is awesome security. It's really effective, easy to use, and the price is great. Check out SimpliSafe here: simplisafe.com/veritasium
    I visited the Compliant Mechanisms Research group at Brigham Young University and spoke to Professor Larry Howell:
    At the above link, you can download 3D-print files to make some of the objects in the video, plus learn more about compliant mechanisms.
    What I learned about compliant mechanisms I summarize in the 8 P's of compliant mechanisms:
    1. Part count (reduced by having flexible parts instead of springs, hinges)
    2. Productions processes (many, new, different enabled by compliant designs)
    3. Price (reduced by fewer parts and different production processes)
    4. Precise Motion (no backlash, less wear, friction)
    5. Performance (no outgassing, doesn't require lubricant)
    6. Proportions (reduced through different production processes)
    7. Portability (lightweight due to simpler, reduced part count designs)
    8. Predictability (devices are reliable over a long period of time)
    Special thanks to Patreon supporters:
    Donal Botkin, James M Nicholson, Michael Krugman, Nathan Hansen, Ron Neal, Stan Presolski, Terrance Shepherd
    Animation by Alan Chamberlain

Comments • 5 795

  • Jingle Jangle
    Jingle Jangle Day ago

    Some. Not all.

  • Dr. M. H.
    Dr. M. H. Day ago

    His first compliant mechanism looks like 2 spoons in missionary position
    Who else clicked the vdo bcuz of this fact? 😄

  • Don Vittorio DiMaggio


  • heresteven
    heresteven 2 days ago

    Good for an artificial heart or lung

  • Mike Fletcher
    Mike Fletcher 2 days ago

    1:37 oh hey

  • Seth Hartson
    Seth Hartson 2 days ago +1

    Congratulations engineering majors you get 4 new required 4 credit classes to learn this

  • Taner Kiral
    Taner Kiral 2 days ago

    how many cycles can a normal light switch take? he said those could take over a million
    how many cycles do any of these things last? that's what I'm wondering right now. This all seems so incredible but my concern with a material bending is always how long it lasts
    those devices are so cool

  • Kimiko Tanaka
    Kimiko Tanaka 2 days ago

    Wait....this isn't Aphex Twin....

  • Ludo Mites
    Ludo Mites 2 days ago

    could these be used to knit spider silk?

  • Roddy Dykes
    Roddy Dykes 2 days ago

    *Samsung:* *sweats nervously*

  • HiTechDiver
    HiTechDiver 2 days ago

    So, one question I have always had, is concerning duty cycles vs duty cycles over time; I've always wondered if how much a factor time was. Simply put, has there been any comparisons of a component going through ten thousand duty cycles, and a like component going through ten thousand duty cycles over 7 years time? Certainly technology and the development of new materials makes these compliant mechanisms more feasible, though my question still stands.

  • Aquila Rondina
    Aquila Rondina 2 days ago

    Samsung: *breathing intensifies*

  • Tree Time
    Tree Time 3 days ago

    Does spring counts as compliant mechanism?

  • Archie
    Archie 3 days ago +2

    9th P should be printable.. 3D that is..

  • fuzzywzhe
    fuzzywzhe 3 days ago

    This moron made a system around nuclear bomb safety that is dependent on pliability of materials over the course of decades?
    Doesn't this man realize that pliability changes drastically over time, and that's not predictable at this point?
    This is why exact mechanisms were preferred. It is entirely understood. It's just simple Newtonian mechanics, not interactions at the atomic level regarding pliability. This man is dangerous.

  • Nathan Lambert
    Nathan Lambert 3 days ago

    I thought most people in mechanical engineering type roles would have already been familiar with flexure based mechanisms.

  • S30V
    S30V 3 days ago

    Build the mantis shrimp supercavitation punching apparatus.

  • the strange gentleman 404A

    Makes you think that in the future robots made completely out of metal will have the flexibility of rubber

  • lxlcentric Val
    lxlcentric Val 3 days ago

    Grab my iPhone ;-)

  • Seu Jorge
    Seu Jorge 3 days ago

    this is the usa i prefer. awesome engineering.

  • Nocturnal RS
    Nocturnal RS 3 days ago

    Titanium is 3d printable? wtf

  • J. Renard
    J. Renard 3 days ago +1

    i was 100% NOT AT ALL READY for this video. my mind is so blown, it is currently floating outside of my body right now 🤯!

  • fomalhaut86
    fomalhaut86 3 days ago

    That is cool.

  • MrOopee
    MrOopee 3 days ago +1

    Title of this video was just weird that I wasn't going to watch it.
    I'm glad I did.

  • DoggeBoi
    DoggeBoi 3 days ago +1

    Wired FLEX, but ok.

  • habirton
    habirton 3 days ago

    Is BYU still a church pretending to be a University or have they evolved?

  • felix crab
    felix crab 3 days ago

    watch escapements have done this for 100s of years and the modern silicon ones are also very impressive

  • 송다훈
    송다훈 4 days ago +5

    this is why I like youtube.
    It gives me amazing information I couldn't even imagine

  • Sir Bomb
    Sir Bomb 4 days ago +1

    I'm sure this has been thought of, but wouldn't flexibility be affected by temperature? Id be worried those titanium pieces would snap in space.

  • Prince
    Prince 4 days ago +1

    This is the most amazing video I have ever seen.

  • Luis Alegría
    Luis Alegría 4 days ago

    that guy I think he doesnt have patience..

  • Rahul Singhal
    Rahul Singhal 4 days ago +4

    I'm a mechanical engineering student studying mechanisms and this video made me realize it's importance.

  • Will Fishing
    Will Fishing 4 days ago

    1:08 It's a pointer finger to thumb stand off...

  • Jared Landers
    Jared Landers 4 days ago

    RIP headphone users (2012 throwback thursdays)

  • Turcan Fred
    Turcan Fred 4 days ago +1

    very nice vid keep it up

  • hollo dollo
    hollo dollo 4 days ago +1

    That guy is definitely not straight.

  • Bleack
    Bleack 4 days ago

    This is the same reason why the old plastic phones with the buttons were more durable than modern smartphones. The plastic in those phones make them able to absorb the force of the impact, which is also a lot of them would scatter into pieces. That way individual pieces that got scattered absorbed a bit of the impact and distributed it among themselves - unlike smartphones that take the hit like a brick and break at slightest bit of pressure

  • Marek Sýkora
    Marek Sýkora 5 days ago

    Looks like Veritasium guy saw a little about mechanical engineering when he is so suprised about flexible iron automatic clutch. This thing is more than one hundred years old. The only inovative thing is that it is made of one peace of iron instead of three peaces joined together by screws. And it is only because of possible laser cutting methods used these days so the production is cheap. And same for that NASA thrusters holder. Thanks to 3D printing it makes sense to do it that way. Otherwise it would be made of several metal pieces weld or screwed together.

  • Marek Sýkora
    Marek Sýkora 5 days ago

    These are exactly the things inside our home appliances that act as stoppers of their life after three years us usage. The producer saved three cents to use this plastic sh*t instead of small iron spring and your wash machine/hairdryier/vacuum cleaner stops working after three years. 'Thank you' for your planned obsolence. Machines build to fail.

  • Socrates Alexander
    Socrates Alexander 5 days ago +1

    Yes, but when you bend a plastic a few times, it breaks.

    • Aadit Doshi
      Aadit Doshi 2 days ago

      3:43 . They stress tested it a million times

  • S J
    S J 5 days ago

    What about its limitations, are there any? why aren't such brilliant innovations not being used in objects we require daily

  • Azriel Jale
    Azriel Jale 5 days ago

    The future looks good

  • mick steinlage
    mick steinlage 5 days ago

    how do you even create something like this

  • Mozart
    Mozart 5 days ago

    But how about material fatigue and maintainability? Unibody parts have to be serviced too, how do you service them?

  • ivan calderon
    ivan calderon 5 days ago +1

    Wow this was amazing, thank you

  • Arjun Jha
    Arjun Jha 5 days ago

    Danaerys - I know this for sure .

  • Galileo
    Galileo 5 days ago +1

    wouldnt the wear and tear of compliant mechanisms be off the chart

    • Aadit Doshi
      Aadit Doshi 2 days ago

      3:43 . They said it was stress tested and works for a million cycles.

  • Nashton
    Nashton 6 days ago +5

    I got so inspired by this video that I went out, bought two textbooks on this stuff, and have now started 3D printing tons of things using this design philosophy. This is why I'm subscribed to you, for showing me these amazing concepts that revolutionize my thinking, thank you!

  • HAQx . org
    HAQx . org 6 days ago

    I absolutely hate that this guy acts like he doesnt understand basic physics, like Wooooow

  • HAQx . org
    HAQx . org 6 days ago +1

    TLDR; metal hinges and plastic bends which can be used in assemblies where regular movements are required.

  • WeesGegroetOnderdaan

    Supercool! No replacement by parts is something of a downside though, isn't it?

  • ClayZ
    ClayZ 6 days ago +1

    OK, RU-clip. I’ll watch it. I guess.

  • Berkeley Pickell
    Berkeley Pickell 6 days ago

    When asked "How long do they last" he talks about fatigue testing, which is great, but my concern with plastics would be more about loss of elasticity as it ages or encounters weather.

  • Erika Reglin-Hormann

    Don't know why but this reminds me of origami. Once you've formed a two-dimensional piece of paper into a three-dimensional body and you're finished, you can't tell the beginning and the end. Sometimes I imagine the cosmos as an "object" within which many objects are contained, which is folded in itself so many times that it is impossible to see the original folding with the naked eye. If, for example, one would fold a piece of surface the size of a football field in origami manner into a body, it would shrink and at the end be as big as a table tennis table, but look like a hazelnut.
    The flexibility and willingness of the shown material in this video to adapt and at the same time develop great forces is remarkable. The more flexible the less quickly resistors can destroy it. However, I'm a little sceptical about plastic ...
    In any case, if a piece of paper were very large, its flat surface could pop up three-dimensional bodies like water lilies on a pond. And yet the two-dimensional would inevitably be connected to the three-dimensional. The "empty surface" would then be the space that holds everything together.

  • Gab Garcia
    Gab Garcia 6 days ago


  • PebblesChan
    PebblesChan 7 days ago

    From experience compliant mechanisms can fail from grit, dirt sand, frozen moisture and other contaminants - just like the butterfly key switch.

    • Jared Landers
      Jared Landers 4 days ago

      Would higher design tolerances account solve this?

  • AesopsRetreat
    AesopsRetreat 7 days ago

    How silly. We've had centrifugal clutches for at least 1/2 a century and this guy has never heard of it? I'll bet that engineer just dropped his perception of this guy down several IQ points. Like he's talking to a child. We used those back in the '60s when we home made mini bikes out of thrown away bikes, rims and lawn mower sideshaft engines. A centrifugal clutch was expensive back then. About $15. That was big bucks back then for a kid. Gas was 25 cents.

  • mahilley
    mahilley 7 days ago

    terrible explanation of backlash

  • Snowleopard75
    Snowleopard75 7 days ago

    at first glance i thought the thumbnail was two spoons having sex

  • skatenec
    skatenec 7 days ago

    Aphex twin logo

  • Andrew Goss
    Andrew Goss 7 days ago

    "That's pretty cool!" "yeaaaahhh....."

  • Rik van der Mark
    Rik van der Mark 7 days ago +2

    I watched this with an almost continuous smile interrupted by periodic surprise ^^

  • stonewall 138777
    stonewall 138777 7 days ago

    I am bender! Please insert girder!

  • Davos Holdos
    Davos Holdos 7 days ago

    4:59 how is that trippy? It plastic.

  • Stanton Moore
    Stanton Moore 8 days ago

    RIP the spot on the camera lens

  • BeAn BeAn
    BeAn BeAn 8 days ago

    Wow things are going to be so cheap and have less replacement-need.

  • Kian Cameron
    Kian Cameron 8 days ago

    Veritasium is starting to sound like PBS

  • anton tan
    anton tan 8 days ago

    Am i the only one that thinking this video is about iphone...

  • Carol Norton
    Carol Norton 8 days ago

    And I thought I didn't like plastic.

  • Karthik C
    Karthik C 8 days ago +71

    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.
    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

    • Karthik C
      Karthik C 3 days ago +1

      +PebblesChan I agree with you on the fatigue testing. Fatigue testing in the lab are not exact representation of real world loading conditions, but it is one of the best ways of estimating usable life through accelerated testing. Regarding the car window switch it is most likely planned obsolescence. Many a times manufacturers follow the "Razor and blades business model". The reason why spare parts are so costly is that, the spares themselves are not expensive as you mentioned but the manufacturer recovers part of the initial cost through spares. Spares also provide a continuous revenue for the manufacturer. It is worth mentioning that the flexure that holds the pendulum in my grandfather's clock works perfectly after close to 70 years of use. It is made of spring steel. I doubt a plastic flexure would last even a decade. Flexures really come in handy in disposable products like foldable plastic forks, food containers etc. They are indispensable when stiction comes into play. The uncertainties posed by friction are completely negated when you use a flexure for a standard pivot. I am not saying flexures are a panacea for all design problems but in most cases they do outperform conventional hinge/pivot.

    • PebblesChan
      PebblesChan 3 days ago +1

      Many are not properly designed and having machines cyclically repeating the same action does not emulate real life where there are substantial differences, variances and exposure to idiots. (No one can engineer against stupidity). I have a car window switch that comprises of the simplest possible machine essentially being just a rod of flexible plastic that pushes onto a copper leaf switch. Just with normal use the end shortens being unable to make the copper leaves to make contact. The biggest problem is that the replacement price of that switch is about $250. In the same vehicle there is a plastic combination stalk mechanism (its second) that now fails to invoke the fast wiper speed unless one deliberately over twists the switch and holds it there. The price for that is about $600. The original plastic combination stalk mechanism failed by not being able to invoke high beam. It's amazing that something that costs cents to make can cost so much as replacement parts.
      What I find most amazing is how pressed metal sheeting can outperform solid cast metal structural components.

    • Karthik C
      Karthik C 4 days ago

      +PebblesChan Yes certain consumer products do have badly designed living hinges and I have had similar experience. However, a properly designed living hinge should last thousands of cycles if not more. They would fail prematurely if they are not designed properly, use of wrong type of plastic, if they are bent over their design limit/excessive force, if they are subject to extreme heat, or if they are subject to UV light(sunlight). Please do not get me wrong. I use them all the time. If you design, use them properly they are shown to last at least a million cycle as the Professor in the video claims. Even a 3D printed flexure lasts hundreds of cycles for me when I use them in my lab for my experimental setups. Often times they simplify design with no assembly required. They are indispensable in applications where you cannot use lubricants. for e.g. MEMS, certain medical devices.

    • PebblesChan
      PebblesChan 4 days ago +1

      Yes and many are crappy with the flexible hinges easily overstressed thus failing and breaking off.

    • Karthik C
      Karthik C 5 days ago

      +skullee Yes They are omnipresent. They are most widely used in disposable food containers to single use clamps used in IV lines. Please keep a close eye on everyday objects and you are bound to find them everywhere!

  • Michael Robins
    Michael Robins 8 days ago +1

    Yet blacks are obsessed with sex, drugs and crime

  • Partly Cloudy
    Partly Cloudy 9 days ago

    Does anyone else look at the title image for this video and "Rorschach style" see one person choking another person?

  • pyrokazama
    pyrokazama 9 days ago

    This was awesome.

  • BillyGnosis
    BillyGnosis 9 days ago


  • Cameron Cox
    Cameron Cox 9 days ago

    Thought Works

  • Sixta16
    Sixta16 9 days ago

    7:05 I was like... wait a minute... WOW!

  • Tower guy
    Tower guy 9 days ago

    5:39 😎

  • M Si
    M Si 9 days ago

    Very interesting. Maybe a bit unnecessary interrupting here and there ;D

  • Fraxlevein
    Fraxlevein 10 days ago +2

    Bender B. Rodriguez liked this video.

  • Sinister Strawberry
    Sinister Strawberry 10 days ago +1

    It's really interesting TBH. It blown my mind away man!

  • Bradley Underhill
    Bradley Underhill 10 days ago

    1:39 the people spying round the corner 😆

  • Jimmy Hendrix
    Jimmy Hendrix 10 days ago +3

    Won't the initial friction of the spin disc possibly damage the drum?

  • Engineering Society
    Engineering Society 10 days ago

    Centrifugal clutches were used from last decade!! Though I loved the mechanism

  • Christopher Ostuni
    Christopher Ostuni 10 days ago +1

    Bender Bending Rodriguez approves this message.

  • Mr. Boma's Balloons
    Mr. Boma's Balloons 10 days ago

    The Apple "butterfly" keyboards use flexible joints like this, and they have a ton of failures and a large number of customer complaints. I like the low profile and minimized key travel, but I had two keys fail and had to take my MacBook in for repairs after less than 2 years.

  • Rad Byte
    Rad Byte 10 days ago

    the elephant I was right

  • idworkhard
    idworkhard 10 days ago +23

    Man, this professor is cool. Big respect!

  • MisterPinhead
    MisterPinhead 10 days ago

    I hate questions where they give you a choice of answers, but it's none of the above. My initial thought was that it would stay in place for that elephant, but then he said "right, left, up, or down".

  • Fahrenheight
    Fahrenheight 10 days ago

    I could learn about this all day.

  • Itzibitzi Satan
    Itzibitzi Satan 10 days ago


  • pianoten
    pianoten 10 days ago

    So you are telling us that the galaxy fold and huawei mate x is 100% better than normal smartphones

  • Daniel Hixson
    Daniel Hixson 10 days ago +1

    I thought this was going to be an Aphex Twin video.

  • Nandakumar Rajamanickam

    one of the best or if not the best.

  • Ron Morales
    Ron Morales 10 days ago

    Zenith has produced the most accurate mechanical wristwatch, Defy Lab, using the same principle in producing a monobloc oscillator taking the place of ~30 components in a traditional balance spring system.

  • E
    E 10 days ago

    Props to you for telling us your ad pitch is at the end of the video so we can skip it. +1 For all of you out there who hate ads, it starts at 11:45.

  • JFK Global
    JFK Global 10 days ago

    that is cool

  • Jacob Taylor
    Jacob Taylor 10 days ago

    I could see a yes in that dudes face at the end.

  • Marko Feller
    Marko Feller 10 days ago

    must be proud of himself, making the world a safer place by making a nuclear bomb safty mechanism.

  • Manan Awasthi
    Manan Awasthi 11 days ago

    My iPad Pro is flexible too!!

    IIIIIawesIIIII 11 days ago

    Wouldn't this suffer in accuracy?