Printing Patterns for sand casting
Posted: Tue Dec 15, 2015 11:32 pm
I occasionally build running model engines. One kit that I bought a while ago was the Atkinson Engine kit designed by Joe Tochtrop. Joe unfortunately died a few months ago and the kit is no longer available. The model is very detailed and accurate with the exception of the cylinder. On the original engines, the cylinder was round with a couple of flanges on it:
http://m8.i.pbase.com/u8/captain_carl/u ... _orig.jpeg
But, in Joe's version he substituted a water hopper type cylinder which is not correct for this engine:
http://m5.i.pbase.com/u47/captain_carl/ ... model.jpeg
I designed a new cylinder that is more authentic, then added draft angles, fillets and shrink allowance. The cylinder was then split it in-half and patterns were 3D printed for casting. I also designed and 3D printed a core mold so that the cylinder could be cast hollow with all water passages. Here are the core mold and pattern in the first pic. The second pic shows a printed mockup of the cylinder to test fit as well as the cast aluminum part that resulted. Patterns and core box were printed in PLA with a 30% infill.


cheers,
c
http://m8.i.pbase.com/u8/captain_carl/u ... _orig.jpeg
But, in Joe's version he substituted a water hopper type cylinder which is not correct for this engine:
http://m5.i.pbase.com/u47/captain_carl/ ... model.jpeg
I designed a new cylinder that is more authentic, then added draft angles, fillets and shrink allowance. The cylinder was then split it in-half and patterns were 3D printed for casting. I also designed and 3D printed a core mold so that the cylinder could be cast hollow with all water passages. Here are the core mold and pattern in the first pic. The second pic shows a printed mockup of the cylinder to test fit as well as the cast aluminum part that resulted. Patterns and core box were printed in PLA with a 30% infill.


cheers,
c