Need More Power? How About 3D-Printed Pistons?

Photography courtesy Porsche

Sure, we don't have flying cars or hoverboards (yet), but there's still plenty of proof that we're living in the future.

Case in point: Porsche has found out how to add 30 horsepower to a 911 GT2 RS by 3D-printing its pistons.

Reportedly weighing 10 percent less than their forged counterparts and featuring an "integrated and closed cooling duct in the piston crown," the pistons are assembled by a process called laser metal fusion, or LMF. This process involves melting a "high-purity" metal powder using an actual laser beam into layers that are then built up into the desired shape—in this case, pistons.

Porsche has already been using 3D-printing to produce items such as the bucket seatbacks for the 911 and 718 as well as various hard-to-find parts for classic Porsches. Still, this is the first time the manufacturer has used this method to manufacture engine components.

Read the full press release below:

 In cooperation with its partners Mahle and Trumpf, Porsche is establishing a new milestone in the use of additive manufacturing processes for highly-stressed drive components.

3D printing technology is already used at the sports car manufacturer in prototype construction, manufacturing spare parts for classic sports cars as well as in other areas. For the first time, the pistons for the high-performance engine of the 911 flagship model, the GT2 RS, are now being produced with a 3D printer.

3D printing allows the pistons to be manufactured with a structure that is optimised for the loads acting on the pistons. As a result, the pistons from the advance development project weigh ten percent less than the forged series production pistons. They also have an integrated and closed cooling duct in the piston crown that could not have been produced by conventional methods. “Thanks to the new, lighter pistons, we can increase the engine speed, lower the temperature load on the pistons and optimise combustion,” explains Frank Ickinger from the advance drive development department at Porsche. “This makes it possible to get up to 30 PS more power from the 700 PS biturbo engine, while at the same time improving efficiency.”

Building up parts layer by layer permits realisation of new and improved designs

There are a number of different technologies for 3D printing. All are based on the principle that the components are built up layer by layer without the need to previously manufacture a special tool or mould. Practically any geometric shape can therefore be realised. The printer can be fed with the design data directly from the computer. Additive manufacturing processes are thus ideal for producing structures that have been designed and optimised by means of artificial intelligence (AI).

The pistons of the 911 GT2 RS were manufactured from high-purity metal powder using the laser metal fusion process (LMF). Here, a laser beam heats and melts the powder surface corresponding to the part contour. Porsche initiated the joint project together with cooperation partners Mahle and Trumpf. The quality and performance capability of the components were validated using measurement technology from Zeiss.

Wide application field and new potential uses for 3D printing at Porsche

Porsche already uses additive manufacturing processes in several areas. For example, a 3D-printed bodyform full bucket seat has been available since May for the model series 911 and 718. Here, the central section of the seat, in other words the cushion and backrest surfaces, is partly produced by a 3D printer. Customers will be able to choose between three firmness levels (hard, medium, soft) for the comfort layer in future.

Porsche Classic also uses additive processes to reproduce plastic, steel and alloy spare parts that were previously no longer available. A release lever for the clutch of the Porsche 959, for example, today comes from a 3D printer. Around 20 reproduced parts for Porsche classic models are currently manufactured using additive processes. This manufacturing technology is also technically and economically interesting for Porsche for special and small series as well as motorsports. 3D printing therefore offers significant potential for Porsche with regard to product and process innovations, which will in turn allow customers to benefit from fascinating and individual products.

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Comments
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300zxfreak
300zxfreak New Reader
7/13/20 5:05 p.m.

Perhaps they can 3D print some IMS bearings that live.

rodknock
rodknock Reader
7/13/20 6:12 p.m.

I can't wait until metal 3D printing becomes somewhat affordable. Even the smaller ones still cost about the same as a new BMW. 

californiamilleghia
californiamilleghia Dork
7/13/20 7:50 p.m.

looking at the picture they are not "ready to use" when they come out of the printer , 

I wonder what the time is to CNC them from a forged slug   compared to printing and finished machining ?

Mr_Asa
Mr_Asa Dork
7/13/20 7:54 p.m.

Much less with the 3D printing, probably.  Forgings generally have a lot of excess to be removed.  I'm used to more industrial forgings than performance vehicles though

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
7/14/20 3:42 a.m.
californiamilleghia said:

looking at the picture they are not "ready to use" when they come out of the printer , 

I wonder what the time is to CNC them from a forged slug   compared to printing and finished machining ?

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

 

 

fidelity101 (Forum Supporter)
fidelity101 (Forum Supporter) UltraDork
7/14/20 9:58 a.m.
californiamilleghia said:

looking at the picture they are not "ready to use" when they come out of the printer , 

I wonder what the time is to CNC them from a forged slug   compared to printing and finished machining ?

this is the big part left unanswered. they show a shiney machined OD and top which is not the case. post processing is required to get the pistons to where they are now. 

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) MegaDork
7/14/20 10:05 a.m.
rodknock said:

I can't wait until metal 3D printing becomes somewhat affordable. Even the smaller ones still cost about the same as a new BMW. 

Having seen these printers in action, I think speed is the key.

In the time it would take to print one piston, a conventional forging method could probably do hundreds.  Engine plants make over 1000 engines every single day- and average of 6 cyl (even 4/6/8 production) that's 6000 pistons a day for one plant.  Call it 24 hour production- that's just over 4 pistons per min made.

Some huge advancements would have to be made for that 3d printed pistons are a reasonable way to make pistons for the masses.

cyow5
cyow5 New Reader
7/14/20 10:24 a.m.
Pete. (l33t FS) said:
californiamilleghia said:

looking at the picture they are not "ready to use" when they come out of the printer , 

I wonder what the time is to CNC them from a forged slug   compared to printing and finished machining ?

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

 

 

Diesel guys can forge two halves and then friction weld them together with some pretty quick production speed, but that also requires post-machining like the printed ones.  

ProDarwin
ProDarwin UltimaDork
7/14/20 10:27 a.m.
Pete. (l33t FS) said:

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

I don't think they could be cast either.  The hollow jacket could not be formed either way.  I think the only 'traditional' method to make something like that would be to assemble a multi-piece piston.

cyow5
cyow5 New Reader
7/14/20 11:00 a.m.
ProDarwin said:
Pete. (l33t FS) said:

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

I don't think they could be cast either.  The hollow jacket could not be formed either way.  I think the only 'traditional' method to make something like that would be to assemble a multi-piece piston.

No idea who uses it, but there is a patent on using a molded salt ring during the casting process. The salt is then dissolved out afterwards, leaving the cooling gallery. 

captdownshift (Forum Supporter)
captdownshift (Forum Supporter) UltimaDork
7/14/20 11:09 a.m.

In reply to Pete. (l33t FS) :

That's what lead Koenigsegg to develop and utilize 3D printing for manifolds less than a decade ago. It's crazy that it's now at a Porsche pricepoint. It honestly means that within the next 10-15 years, if not sooner, it'll be the production norm. 

All I can think of is a 4age or KL series motor fitted with lighter, more efficient 3D printed pistons with better thermal tolerances. Let alone if Lexus were to decide to implement and test the development of the technology in creating a second generation LFA. 

 

 

And we haven't even gotten to it's practical uses in suspension arm applications yet. 

buzzboy
buzzboy Dork
7/14/20 11:13 a.m.

I've read up on 3D metal printing and it sounds like there are issues getting uniform metal layers. Like there are pockets of different grain structure inside the metal. That sounds like a bad thing in a piston?

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
7/14/20 3:20 p.m.
cyow5 said:
ProDarwin said:
Pete. (l33t FS) said:

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

I don't think they could be cast either.  The hollow jacket could not be formed either way.  I think the only 'traditional' method to make something like that would be to assemble a multi-piece piston.

No idea who uses it, but there is a patent on using a molded salt ring during the casting process. The salt is then dissolved out afterwards, leaving the cooling gallery. 

IIRC the 6.7 Cummins uses something like that.

And when the operator lets the oil changes go and it sludges up inside the piston, the crown melts down.  They NEED the piston cooling to function.

cyow5
cyow5 New Reader
7/14/20 3:33 p.m.
Pete. (l33t FS) said:
cyow5 said:
ProDarwin said:
Pete. (l33t FS) said:

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

I don't think they could be cast either.  The hollow jacket could not be formed either way.  I think the only 'traditional' method to make something like that would be to assemble a multi-piece piston.

No idea who uses it, but there is a patent on using a molded salt ring during the casting process. The salt is then dissolved out afterwards, leaving the cooling gallery. 

IIRC the 6.7 Cummins uses something like that.

And when the operator lets the oil changes go and it sludges up inside the piston, the crown melts down.  They NEED the piston cooling to function.

Yep, that's why oil galleries in general can be problematic on production vehicles. The gradual crud build-up reduce the cooling effectiveness until ka-blooey. The friction-welded approach I mentioned also produces protrusions into the cooling channel (although there are also patents that help), and this can pose problems down the line, too. 

Recon1342
Recon1342 Dork
7/14/20 4:46 p.m.

Cool!

Honsch
Honsch New Reader
7/14/20 5:16 p.m.
rodknock said:

I can't wait until metal 3D printing becomes somewhat affordable.

It's called skill with a MIG welder.

fidelity101 (Forum Supporter)
fidelity101 (Forum Supporter) UltraDork
7/15/20 8:19 a.m.
ProDarwin said:
Pete. (l33t FS) said:

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

I don't think they could be cast either.  The hollow jacket could not be formed either way.  I think the only 'traditional' method to make something like that would be to assemble a multi-piece piston.

Is it Turbo to want more out of life?

these specific parts due to their internal geometries cannot be produced another method, this is how you use additive manufacturing correctly whereas normally someone wants you to copy something with the technology then complains about the cost. 

oldeskewltoy
oldeskewltoy UberDork
7/15/20 9:53 a.m.

Not just pistons.........

 

ProDarwin
ProDarwin UltimaDork
7/15/20 10:11 a.m.
fidelity101 (Forum Supporter) said:
ProDarwin said:
Pete. (l33t FS) said:

Given that it sounds like they have a hollow cooling jacket under the crown, I'm going to guess the design can't be forged, just cast, if traditional manufacturing processes were to be used.

I don't think they could be cast either.  The hollow jacket could not be formed either way.  I think the only 'traditional' method to make something like that would be to assemble a multi-piece piston.

Is it Turbo to want more out of life?

these specific parts due to their internal geometries cannot be produced another method, this is how you use additive manufacturing correctly whereas normally someone wants you to copy something with the technology then complains about the cost. 

Well, you could make any of these designs another way, they might just be painfully expensive to do.  You could machine layers and weld them together, etc.

 

Agreed, doing geometry that is otherwise way to complex/expensive is a great use. OR for prototyping or production runs of very low numbers - that's what I use it for.

 

And yes, a connecting rod is a great place to do it.  Make a box section instead of an I beam...

GIRTHQUAKE
GIRTHQUAKE Dork
7/15/20 11:02 a.m.

Can you imagine the number of forelorn, old/odd engines this now can return to working order? Like old flatheads especially with their awful bores (looking at you, Buick straight 8!) and huge lug pistons could now chop literal POUNDS of rotating mass out of the engine. This could lead to some wild stuff if the cost comes down to our hobbyist level.

Mr_Asa
Mr_Asa Dork
7/15/20 11:14 a.m.
buzzboy said:

I've read up on 3D metal printing and it sounds like there are issues getting uniform metal layers. Like there are pockets of different grain structure inside the metal. That sounds like a bad thing in a piston?

I'd think that post process heat treating would solve that.

BikingEngineer
BikingEngineer New Reader
7/17/20 10:05 a.m.
Mr_Asa said:
buzzboy said:

I've read up on 3D metal printing and it sounds like there are issues getting uniform metal layers. Like there are pockets of different grain structure inside the metal. That sounds like a bad thing in a piston?

I'd think that post process heat treating would solve that.

Heat treating can help a little bit with cleaning up the grain structure but it can't do everything. Most heat treatments are designed to either temper brittle phases, manipulate precipitation hardening alloys, or add surface treatments. It's nearly impossible to add anisotropy or grain recrystallization to a structure, which are the main benefits to forging.

The process that Porsche is using is better than most 3D metal printing, it uses a high powered laser to sinter metal powder together to build layers. Cheaper metal printers (ones that cost less than a house) use a metalized polymer filament, then remove the polymers with chemicals, then sinter everything in an oven leaving a very uniform structure throughout though not necessarily a strong one. The laser sintering printers let you somewhat manipulate the grain structure throughout the part, as well as giving you some localized alloying control with some setups, they also have much finer resolution for greater dimensional control (on the order of ~50 micrometers for the really high end printers). This comes at a buy-in on the order of $1,000,000 or so (and up, of course). 

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