Complete, new, Austin 7 Engine?

[Tony Griffiths]

OK, sorry, one is not available - but this amazing video does show the possibility of 3D printing one. If an entire rocket engine including the complex pipework, etc. can be made in this way, why not the structural parts of an IC one? https://www.youtube.com/watch?v=kz165f1g8-E

[Chris KC]

It's a process I'm sure we'll be hearing more about, even in the A7 world.

I'm by no means up to speed on the topic, but as I understand it the kind of printing which is commercially available here and now could potentially make small batches of small metal parts reasonably economically, with something like the strength and quality of a sintered part. Perhaps better for fixtures and fittings than for con rods.

Where it really is useful is prototyping - say you design a part and you want to test the fit in the vehicle before committing to make a real one - draw it up in CAD and print one off in plastic and it should be dimensionally accurate.

Rockets are basically big tin cans, not sure we'll be seeing fully 3D-printed IC engines for a while...

[dickie65]

I have seen some stunning parts made from metal powder fused together by multiple laser beams.
I would not describe the process as printing though.
Laser welding of cast iron is now a useful thing. I have been brave and had a Nippy Chromidium block Laser welded.
All the valve seats have been built up some of the deck stud holes have been filled and the side water branch stud holes have been filled
The best repair is of a hole in the lower part of one cylinder inside the valve chest.
With Lazer welding there is no pre heating needed as the heat concentration is tiny and very fast to heat up.
I would have bought a new block but as none are available at the moment I decided to repair the 9E Chromidiun block, it worked out to cost less than a new block and has saved a genuine part from scrap.
Sorry for the slight Hi Jack of post, But this is an offshoot of the metal fusing /sintering / printing.

[jansens]

They already use it for some parts such as manifolds. Basically it's powder laid down in tiny layers then laser welded together. Currently it is extremely slow and very expensive.

I have used plastic 3D printing at home to make wax models then used them to cast aluminium but just small, simple things. There are commercial machine around that can 3D print the sand cores used in casting and they definitely use them to make up the patterns for engine blocks and the like: https://www.voxeljet.com/industrial-3d-p...ng/vx1000/

You can see the metal 3D printing of the manifold in action here. The Papadakis films are always excellent. They 3D print an aluminium intake manifold and later some Iconel exhaust headers.




I am currently making a working 3D printed Polish Enigma machine from plastic with the idea that I can eventually have parts reprinted in metal to make a much more solid and long lasting replica machine.

Simon

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It is printing even if it's layers of powder laid down and fused with lasers. That's how laser printers work, a layer of toner is transferred to a piece of paper then fused in place by heat. The laser in a laser printer is there for forming the image, the fusing is done with conventional heater elements.

In 3D printing there are slightly different process. One is process is called SLS, Selective Laser Sintering. They build up layers of powder, then the laser fuses the particles together then they do the next layer on top. They typically heat up the base powder to just under melting point then the laser gives it that little push to sinter the stuff together. There is also SLM, Selective Laser Melting. Here the laser is actually fusing or welding the powder together. I think the main difference is with sintering you can fuse different materials together where as with the melting you do single pure materials.

Normal plastic type printers use a process called FDM, Fused Deposition Modelling, where a nozzle squirts out the material in layers on top of each other.

The beauty of the SLS/SLM process, apart from being able to do metal parts, is you can sometimes build things without what's called support. In normal FDM printing if you print over hanging parts you also have to print a support structure underneath them. You can't squirt out layers of stuff into thin air (well, you can to some degree). You have to take this into account when designing and printing your parts. Once printed you then need to remove the support and clean up the parts. I have modelled my entire Enigma machine to not need support on any parts which was quite a challenge.

With SLS/SLM because it is building up layers of power but only fusing the solid bits you can sometimes do away with needing support because the unfused powder provides that function to some degree. Heavier parts will still need some support so they don't settle in the powder. You can see they use support in the model of the manifold above.

There is also SLA, stereolithography, which is using lasers to fuse together materials in layers but using a bath of liquid resins set with a laser.

Then you get into Electron Beam Melting, EBM, but I think that is for metallic parts only.

When I worked in the film industry we used a lot of FDM printing for simple bulky things, SLA for very find props and details and sometimes had things done in metal using SLS (we had to send those out).

Simon