CAD, 3D printer, intake manifold

[merccom]

So I’ve been thinking pretty deeply lately about technology and fuel mileage and suddenly I had an epiphany.

Is there some reason you couldn’t design an intake manifold in CAD and just print it up with a 3D printer?

Manufacturers have been building ABS manifolds for years so why not.

I figure use one of the pro versions of desktop dyno to figure out the specs you need to maximize performance in whatever power band and then just put it into CAD and print it.

I realize it would be better if you could change the cam to go with it but, one step at a time.

Thoughts?

[Duffman]

When I was doing Formula SAE back around 2000, one of the other teams had done it.

[ProDarwin]

Yes and no.

As a Mechanical Engineer who uses CAD all day with extensive experience in 3D printing (I owned my own printer at one point), I offer this: You could use it to test, but not as a permanent solution.

-It likely wouldn't handle the stresses.
-The ABS printing material also absorbs moisture, oil, gas, etc. which would seep out the underside of the manifold over time creating a mess in your engine bay.
-Many intake manifold have coolant flowing through them, at least briefly, which creates a whole new set of problems combined with the above
-Given the heat in the engine bay, the mounting surface/close to the head would be very likely to deform in certain conditions

[Sven7]

Not to mention you'll have a nasty stepped surface inside and out.

[ProDarwin]

Originally Posted by Sven7

Not to mention you'll have a nasty stepped surface inside and out.

Not really. A 0.005 step wont do much of anything. I've made some pretty complex curves with a 3D printer that did 0.010 layers (including a UAV wing).

[merccom]

Originally Posted by ProDarwin

Yes and no.

As a Mechanical Engineer who uses CAD all day with extensive experience in 3D printing (I owned my own printer at one point), I offer this: You could use it to test, but not as a permanent solution.

-It likely wouldn't handle the stresses.
-The ABS printing material also absorbs moisture, oil, gas, etc. which would seep out the underside of the manifold over time creating a mess in your engine bay.
-Many intake manifold have coolant flowing through them, at least briefly, which creates a whole new set of problems combined with the above
-Given the heat in the engine bay, the mounting surface/close to the head would be very likely to deform in certain conditions

so kinda but you would need to coat it in some kind of high temp sealer and probably need to use a phenolic flange that actually bolted to the head.

would also have to figure out how to deal with EGR.

i guess the other option would be to use it for a limited amount and then use it as a template or mold so you could cast a real one.

[graydonengineering]

I am a 9 to 5 CAD user with rapid prototype experience as I would agree with what as been said. 3D prints tend to be brittle and fragile. The layering/cooling of the material leaves a part that is not completely homoginous so cracking is a big problem when trying to use 3D prints as actual parts. It is very powerfull technology but has some major limitations. If you have the ability to cast off one to make the final product, I would go for it!

[NachtRitter]

Sounds like if you could print it in wax and then use lost wax sand casting, it could be beneficial?

[merccom]

Originally Posted by NachtRitter

Sounds like if you could print it in wax and then use lost wax sand casting, it could be beneficial?

just print the negative an cast it out of JB weld

[ProDarwin]

Regarding coatings, the ABS used by most FDM printers can be "blended" using a paint brush and acetone, it melts/welds the surface together making it significantly stronger and smoother. It takes a lot of time to do this though, unless you have a misting chamber.

You could certainly get away with one for a while, depending on the car. V-engines, where the manifold is supported equally on both sides by the head would be much easier. Engines like the 4-cyl in my Saturn would be difficult as the manifold pretty much hangs off the back of the engine.

Originally Posted by NachtRitter

Sounds like if you could print it in wax and then use lost wax sand casting, it could be beneficial?

You can investment cast directly off ABS. I use it for prototype stuff at work. You'd still need a finishing operation on the mating flanges and and screw holes though. In the end it would still cost as much as or more than making a custom manifold out of sheetmetal.

Originally Posted by merccom

just print the negative an cast it out of JB weld

You can't, unless you print a multi-part mold, which would be a total *****.