3d printing an engine block

[gadabout]

Hi,
I’m thinking to get an engine block 3d printed, say a Seal block, what alloy would be good to get it done in ? 6061 or the ALSiMg ?
Thanks
Mark

[Jasonb]

I've only had Aluminium parts done in the ALSiMG but they all had quite thin sections compared to their length so the stronger alloy seemed the way to go. For something quite chunky like an engine block would probably opt for the 6061.

Treat the print a bit like a casting with machining allowances on the flat surfaces and crank/cam shaft bores. I would not print any of the tapped holes.

[gadabout]

Jason, thanks
The ALSiMg works  out at 84$ the 6061 at 135$, wondered if it was worth the extra cost
Mark

[Jasonb]

Probably not, machining of the 6061 may be a bit easier but I've not had problems with the other.

[gadabout]

Jason,
Would you print it with the drilled holes in place ( undersize) but not threaded ?
Thanks
Mark

[Jasonb]

I think I would leave all the small tapped and clearance holes solid, just put an undersize one each end for the end covers and possibly the camshaft

[gadabout]

Jason,
Do you think they wouldn’t form well or be out of place slightly?
Thanks
Mark

[Jasonb]

Placement seems OK but they do come out about 0.2mm undersize so as you end up having to drill them out anyway may as well have the flexibility of slight positional adjustment if needed.

I don't think it would make a lot of difference to the costing a s the amount of powder used won't be much less than printing solid.

[Jasonb]

I believe Model Engineer & Workshop Mag is soon to publish a series of articles where test prints were subject to various tests, I understand the results are more than promising.

As for pull out of studs, I did a basic test with a M4 x 0.5 metric fine thread 3mm long into the ALSiMG and was quite happy with how well it held up. the way the part is orientated is how it was printed so the load would be trying to pull the layers apart.

<a href="https://www.youtube.com/watch?v=zSeL2acqw5A" target="_blank">http://www.youtube.com/watch?v=zSeL2acqw5A</a>

I have also been quite happy with machined surfaces, as I almost exclusively use carbide these days it did not bat an eyelid and no signs of excessive tool wear that was with uncoated cutters. not needed to file them much, just knock off slight burrs around the edge of machined surfaces but did not seem to affect my needle files and have not noticed any problems with HSS drills or taps..

My grains seemed to come off in curls much like aluminium castings, not as stringy as 2014 or 6082 but definately not granular like cast iron. Surface is smooth but not as reflective as a similar cut on solid block, certainly can't see grains with the naked eye. Nearest I would say to it is if you have ever machined the angle brackets that come with the DROs then the 3D prints machine much like those aluminium brackets.

Crankcases that I have seen 3D printed have tended to be for model aircraft. Some are for top class pylon racing which will certainly see far more extrems of heat and compression ratios than a seal sat on a display stand. The one pictured is good for 34,000rpm without blowing the cylinder/head off the crankcase.

[petertha]

Crankcases that I have seen 3D printed have tended to be for model aircraft. Some are for top class pylon racing...

Very interesting, Jason. I'm familiar with that class of racing. Can you direct me to any links, articles etc. describing the engine/print details?
I seem to recall Profi was based in Ukraine, maybe thats all messed up with the conflict. The 3DP says 'England' - maybe a design collaboration with Profi or nod to original design or...?

[Jasonb]

The cylinder is a Profi one, the crankcase was printed.

https://www.homemodelenginemachinist.com/threads/3d-printed-metal-engine-parts.36152/page-2#post-425872

https://www.homemodelenginemachinist.com/threads/metal-3d-print.36238/page-2#post-413997

https://www.homemodelenginemachinist.com/threads/metal-3d-print.36238/#post-413387

[petertha]

The cylinder is a Profi one, the crankcase was printed.

https://www.homemodelenginemachinist.com/threads/3d-printed-metal-engine-parts.36152/page-2#post-425872

https://www.homemodelenginemachinist.com/threads/metal-3d-print.36238/page-2#post-413997

https://www.homemodelenginemachinist.com/threads/metal-3d-print.36238/#post-413387

Thank you. Sheesh, I even posted in one of the links, no wonder it seemed familiar. Must remember to take my memory pills

[lohring]

I'm not sure how the latest Profi 40 pylon engines are made, but they were investment cast in the past.

Lohring Miller

[AlexS]

If you want to reduce brittleness and improve strength/hardness of printed parts. Could add an T6 heat treatment, but would increase price (most batch price not per piece).