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Transportation Printer Technology

Porsche Found a Way To 3D-Print Lightweight Pistons That Add More Horsepower (thedrive.com) 67

An anonymous reader quotes a report from The Drive: With select bucket seats from the 911 and 718 as well as various classic car parts -- including clutch release levers for the 959 -- already being produced using 3D printing, Porsche is more familiar with the technology than most. Now, the automaker is taking things even further, 3D printing entire pistons for its most powerful 991-gen 911, the GT2 RS. Although it doesn't sound like these 3D-printed pistons will actually be found in many production Porsches anytime soon, they represent a bit more than just an engineering flex. There are some very real mechanical benefits here. For starters, they weigh 10 percent less than their forged equivalents and feature an integrated and closed cooling duct in the piston crown that's apparently unable to be reproduced using traditional manufacturing methods. The decrease in weight and temperature results in an extra 30 horsepower on top of the GT2 RS's already mighty 700.

Produced in partnership with German auto part maker Mahle and industrial machine manufacturer Trumpf, the pistons are made out of a high-purity metal powder developed in-house by the former using the laser metal fusion process, essentially a laser beam that heats and melts the metal powder into the desired shape. The end result is then validated using measurement technology from Zeiss, the German optics company best known for camera lenses.

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Porsche Found a Way To 3D-Print Lightweight Pistons That Add More Horsepower

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  • It's about economics (Score:4, Interesting)

    by MasseKid ( 1294554 ) on Tuesday July 14, 2020 @08:16AM (#60296766)
    This is not something that couldn't have been physically done without 3D printing, however it was not economical. Most car parts can be substantially improved if you don't mind a car costing $400,000 instead of $40,000. It is nice seeing 3D printing becoming affordable enough to include in car parts, even if they are luxury car parts.
    • Not true (Score:5, Informative)

      by Wdi ( 142463 ) on Tuesday July 14, 2020 @08:47AM (#60296826)

      The reason for using 3D printing in this project is that the new piston contains optimized twisted oil-cooled channels which could not have been added by drilling into a solid block of metal, or casting.

      • Re:Not true (Score:5, Informative)

        by SharpFang ( 651121 ) on Tuesday July 14, 2020 @09:23AM (#60296918) Homepage Journal

        Stuff like that is doable by casting, though hard to do on bulk scale, and probably more expensive than 3D printing. You prepare the die from a material that is destructible by means the final cast is not, say, a reactive metal that can be dissolved in a kind of acid that won't damage the piston.And obviously you must produce a new die for every single piston you make, can't cast a thousand of them in one die like in normal casting. So they aren't inventing the wheel here, they just apply a new technology that is rapidly becoming affordable, to a problem that had a prohibitively expensive solution.

        • Re:Not true (Score:5, Informative)

          by Smidge204 ( 605297 ) on Tuesday July 14, 2020 @09:42AM (#60296988) Journal

          Except now you have case aluminum pistons heads, instead of billet or forged heads. Cast aluminum isn't as strong since you need to use specific alloys for good quality parts, meaning you'd need to use more material, and you'd have to watch out for internal stresses and shrinkage that all castings have problems with.

          If something like this could have been done, then it would have been done already even if it was ridiculously expensive... high performance motorsport has deep pockets for R&D and a ~5% boost in power is not something they would pass up trying for.
          =Smidge=

          • That is what I wondered. I am sure with 3d printing they can make shapes which are lighter and more complex, provided they are strong enough. But as a rule they are less strong.
            So what is the reasoning? Maybe there are advances in strength? ? Maybe there is something about the GT2 RS which is relevant: it's turbocharged with a rev limit at 7200 . Maybe the improved cooling is more important than extra strength.

            • Pistons' strength don't need to change much for high RPMs, the valvetrain does. Turbocharging increases the cylinder pressure more than using a high compression engine, because a really high compression engine is still under 22:1 (IDI diesels used to regularly be around there) but turbocharged engines regularly get more than 20 psi of boost now.

              Making the pistons lighter reduces vibration, though, and Porsche mostly runs flat engines which are not Boxer engines (although I believe they have built some Boxer

              • The claim is that the lighter pistons allow to increase rpm. But you say the limiting factor is the valvetrain. That seems like a contradiction. I don't see how lighter pistons benefit the valvetrain but I can imagine that when turbocharging there is extra stress on the valves and that this has to be compensated by lowering rpm.(I believe the GT3 does up to 9000 rpm)

                That lighter pistons reduce vibrations I can see. But what is the limiting factor there? The rod bearings?

                • by modecx ( 130548 )

                  Piston velocity long been the basic limiting factor to RPM. You can only push a piston so fast before the rings weld to the cylinder wall / or eat up the fancy coatings they put in modern engines. It's a surprisingly low speed, given the RPM some engines turn.
                  That's why really high RPM engines are short stroke / oversquare, whereby the piston accelerates less in its travels, and reaches a lower maximum velocity for any given RPM. On a high revving sportbike, for instance, that number can be as high as in th

          • by Shark ( 78448 )

            Well, the 3d printed piston isn't billet or forged either... It obviously is resistant enough to do the job but I wouldn't compare the resulting material to billet or forged either. In fact, my guess is that it would quite comparable to an alloy casting.

        • It is most likely not a new technology but an old one: laser sintered 3D printing.
          German engineer are doing 3D printing since 30 - 40 years.

          Hobbyist small scale "maker" 3D printing, that is relatively new.

        • Stuff like that is doable by casting, though hard to do on bulk scale, and probably more expensive than 3D printing. You prepare the die from a material that is destructible by means the final cast is not, say, a reactive metal that can be dissolved in a kind of acid that won't damage the piston.And obviously you must produce a new die for every single piston you make, can't cast a thousand of them in one die like in normal casting. So they aren't inventing the wheel here, they just apply a new technology that is rapidly becoming affordable, to a problem that had a prohibitively expensive solution.

          Agreed. I've designed quite a few 3d printed metal parts. Typically we only turn to 3d printing when casting or machining becomes too expensive, or because of lead time. Unless unless it's being designed for aesthetics, the printed parts always come out heavier than the machined equivalents due to the inferior material properties.

      • That's not true. This could be investment cast, it would just be exceedingly expensive.
      • by Luthair ( 847766 )
        There is a company called CZinger which has developed a prototype supercar similarly - https://www.topgear.com/car-ne... [topgear.com]
    • by AmiMoJo ( 196126 )

      The Porsche Taycan, their first EV, is very good. Best handling of any EV, decent range, fastest charging of any EV. Rather expensive but it is a Porsche I guess.

      Hopefully they continue to develop that technology and move away from fossil fuels.

      • by spth ( 5126797 )

        It is not their first EV.

        Their first EV was the P1 in 1898.

        • Right, kinda.

          Except that was Dr. Ferdinand Porsche (VW guy), not Dr Ferry Porsche of Porsche cars (356 guy). And don't forget Butzi (the grandson, 911 guy).

          Personally for what a 718 would cost, I'd rather get a 356, 912, earlier 911, or 914 and have the zelectric company out in California do their Tesla drive train conversion.

          No, sorry, that is a lie. For what a 718 would cost I'd restore my rusty 356C coupe (one of the last made) and pay off my mortgage.

    • by thegarbz ( 1787294 ) on Tuesday July 14, 2020 @08:59AM (#60296852)

      Not true. The specific design absolutely can't be done without 3D printing. In many cases your alternative is only to forge and drill which puts serious constraints on the *internal* design of a semi-solid object. You can't machine them this way (physically not possible), you can't forge them this way (physically not possible).

      It's not just economics. 3D printing metal has opened up new possibilities for internal construction which literally have no other possible alternative when a requirement is to maintain a single solid piece of metal in the end.

      • by Anonymous Coward

        Quick, cheap, durable.

        Pick any two, that's what you will get.

        • Quick, cheap, durable.

          Pick any two, that's what you will get.

          That comment has only ever applied as a trade-off to using a technology available. It has never applied to technology improvements or new technologies being developed.

          I'll take all three, just as I constantly have. Hell my last car is cheaper, more durable, and rolled off the production line faster than the Ford Model T ever did. And don't be under the delusion that laser sintering somehow makes parts less durable, depending on application you most definitely get both the cheapest, fastest and most durable

      • by Ogive17 ( 691899 )

        It is absolutely possible. You can 3D print the mold negative (1 time use) that is then melted away (or dissolved) once the piston cast is complete.

    • by ranton ( 36917 )

      This is not something that couldn't have been physically done without 3D printing, however it was not economical.

      Well they did say it couldn't be reproduced using traditional manufacturing methods, not that it was impossible without 3D printing. There is probably nothing 3D printing can do which is literally impossible without 3D printing. It is simply a manufacturing method with its own set of pros and cons. Almost every story we ever see that says 3D printing has made something possible is really saying 3D printing has made something economically feasible.

      Although I guess a slightly different reason is when 3D print

      • by Sique ( 173459 )
        There are things you can't do without 3D printing of some sorts: Internal holes for instance without a connection to the outside world. You could try something by forging different layers with the holes previously cut out together, but that is just another way of 3D printing it: with pre-printed layers, and for practical reasons, you have to resort to some minimum thickness for the layers, which makes the resolution of the result worse and costs more material for the same strength.
    • This is not something that couldn't have been physically done without 3D printing, however it was not economical. Most car parts can be substantially improved if you don't mind a car costing $400,000 instead of $40,000. It is nice seeing 3D printing becoming affordable enough to include in car parts, even if they are luxury car parts.

      I would guess as the tech matures it will become cheaper and make its way into more cars; I remember being at a trade show 20 years ago and seeing a demo of a 3D printing setup designed for use by deployed military forces. When I asked them about the quality vs. normal parts they said they are equal or better. Then, cost was not the issue but the ability to produce a part to satisfy a need without having to load a one off part on a plane and ship it; saving a significant amount of time.

      • by Jaime2 ( 824950 )
        Mass produced vehicles will probably never do this. Forging is an excellent way to produce pistons, and forging is well suited to high volume for several reasons: initial cost is high, but unit cost is low and production rate is very high. The four percent power boost will never be worth it for a engine that is produced by the tens of thousands.
    • by sconeu ( 64226 )

      This part IS for a $400,000 car.

    • Porsche doesn't even put the 911 GT2 RS on their website, so it's hard to get direct, current information, but the 2019 model had a *starting* price of $294,450 [caranddriver.com], so this particular car is quite a bit closer to $400,000 than $40,000 in cost, though the technology being implemented at all is hopefully a sign that things are heading in the right direction.
  • Just the Start (Score:5, Interesting)

    by ytene ( 4376651 ) on Tuesday July 14, 2020 @08:19AM (#60296774)
    On the one hand, I suspect that this is just the start of what can be done with 3D printed metal parts for engines and other high-stress environments. Bugatti have successfully 3D-printed brake calipers from titanium, for example, again getting better strength for less weight.

    And imagine what it would be like to be able to 3D-print an engine block and head, which means that all the oil and water ducting could be perfectly formed, examined "in build" and tuned and flowed perfectly.


    On the other hand: I really feel that we should be transitioning to EVs now. That doesn't mean that we should stop this sort of R&D, but maybe we should take a look at how we prioritize R&D for internal combustion engines. On balance, I guess we should applaud this: "more power" can probably also be read as "same power for less fuel".
    • This isn't really new in the manufacturing world, it's just new specifically to pistons. There are already several major mechanical equipment producers using 3D printing processes in their production equipment. The off the top of my head I can think of is Rolls Royce who have been 3D printing components of their Advance engines.

      It's not like this technology can't also be used for EVs. I mean technically Tesla used 3D printing in their cars ... though to fix a minor design flaw in a piece of plastic rather t

    • Although I share your opinion about electrical propulsion, I think the heavy batteries will remain a show-stopper for commercial aviation for a long time. But this could make aviation engines lighter and probably even improve the weight of electrical engines. I can imagine that synthetic fuels, made from carbon dioxide and water, and combustion engines are the most viable option for aviation.
    • by lazarus ( 2879 )

      Porsche is putting a lot of R&D into materials science right now. They recently invented a new brake rotor using thin layers of tungsten carbide [youtu.be] which is a nice middle ground between iron rotors and carbon ceramics.

      re: EVs. A lot of this development is flow-through. Lighter rotors make a big difference (unsprung weight) to fuel economy / range for instance.

    • On balance, I guess we should applaud this: "more power" can probably also be read as "same power for less fuel".

      I don't think so. Power is energy per unit time. Lighter pistons (and presumably valves) means the engine can hit a higher RPM. That is, it generates more power because it's burning fuel faster. Not more efficiently.

      3D printing could still be used to increase efficiency. In a gasoline engine, the combustion pulse expands out as a wave emanating from the spark plug [youtu.be], so some of the energy ge

      • Engines are rated in both IHP (indicated horsepower) and BHP (brake horsepower). IHP is a calculation based on the cylinder pressure, and engine configuration (bore, stroke, number of cylinders) and BHP is what you measure on the Dyno (brake) and it includes all of the internal losses of the engine. The higher the ratio of the two are, the more efficient the engine is.

        Lighter pistons will not necessarily increase IHP, but they will increase BHP but they do allow you to extract more power from the fuel beca

  • When it comes to sintered processes, there are two keywords you have to look for:

    1. Densification - sintered objects as-sintered have low material density. This negatively affects material properties, because there's low mechanical adhesion between grains. Densification (forging, pressing, rolling, cold or hot isostatic pressing), is used to increase the density and radically improve mechanical properties of as-sintered objects.
    2. Heat treatment - sintered objects require some sophisticated heat treating,

    • by sremick ( 91371 )

      I doubt they are sintered. That's just used for prototypes. Likely they're using Selective Laser Melting, which is different and fully melts the metal together.

      https://en.wikipedia.org/wiki/... [wikipedia.org]

      Electron Laser Melting is a similar process, but TFA does explicitly mention lasers.

      • the summary mentions laser melting. The video indicates strenght is good which woudl be my only question.

  • The Chinese last month. You will soon see economical, quality 3D printed pistons for every car on the road today on ebay in just a few weeks.
  • by sinij ( 911942 ) on Tuesday July 14, 2020 @09:12AM (#60296892)
    I am glad Porsche pioneering work, but I wouldn't want to be an early adopter of this technology. Cost of pistons, plus increased chances of having replacement short block when one of these pistons grenades the engine as a result of stress fracture. Last but not least, what is going to happen when sludge forms inside oil passages?
    • by Anonymous Coward

      Last but not least, what is going to happen when sludge forms inside oil passages?

      If you aren't willing to tear down, clean and rebuild your engine every 10,000 miles to keep it at top operating efficiency, you don't deserve to even own a car.

      • by sinij ( 911942 )
        Exactly. Rod bearings is a maintenance item on some M BMWs. Why would I expect anything different from Porsche?
      • Pah, if you didn't forge your own car from bare rock that you dug up with your naked fingers, squeezed liquid in you buttcheeks, and ground with your eyelids, you don't deserve to even think about cars!

  • This is like inventing a better buggy whip in the year 1900.

  • Pistons? We don't need no stinking pistons! Next thing, they'll be adding a bridle and a bit!
    • But you need lithium and other nasty chemicals that go up in flames if they even touch water or even air.

      We should have gone fuel cell. Gasoline has an unbeatable energy density. Synthetic gasoline is pure and can be made cleanly. Fuel cells convert the energy cleanly. CO2 can and should be recovered and recycled.
      It's really the smart choice.

      But hey, "people" are buying iPhones and fixies and voting DemocRepublicratan, so what do I know...

      • Lithium battery fires are in the news because they are new. There are many more gasoline fires every day.
      • by Sique ( 173459 )
        Fuel cells are just a very inefficient way to use electricity in cars. Yes, the storage density is great, but that's about it. Instead of 95% energy efficiency as with accumulator batteries, you are at 40%. And you know that recovering and recycling CO2 costs at least as much energy as you got from in the first place?
    • by jlv ( 5619 )

      Darn, I came here to post the same thing. None of my cars have pistons anymore.

  • You can see it with tools. And gears.
    Sure, it is usable, but sintered stuff always breaks easier, doesn't last as long, and generally the crystal structure is Chinesium-grade.

    The main reason it's done, is actually that it's much cheaper.

  • This is truly the final golden age of ICE cars. Just about every manufacturer makes a 700 HP vehicle. With computers controlling traction, suspension, steering, fuel burning, comfort, entertainment, navigation, safety features, etc.

    However the next generation of cars and trucks will be electric, just about anyone can see that (although some are still in De Nile).
    • That's just your perception. You don't actually expect progress to stop at one technology and somehow jump onto another. Progress drives everything and progress in a technology only ends when the technology has been made obsolete by another technology.

      So for example do people make bows and improve their designs, because these are still used in sport, even when guns and rifles have obsoleted their use as a weapon a long time ago.

      And as long as we keep pumping up oil and refine it will there be combustion eng

  • What's the point in marginal improvement to a soon to be obsolete ICE age technology?

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