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Lost Foam Casting is a process in which a foam pattern is made of what ever object is desired then the part is cast and the foam is burned off in the process. It is a type of investment casting, similar to lost wax casting. Since one of the types of foam used is ABS, I thought I would try lost ABS casting where instead of foam a thin filament of ABS is used. So using a Think-o-Matic 3D printer, which extrudes ABS, I printed up a few things to try casting. My first attempt did not go well, actually the results were dismal. Since I was using greensand and I did not vent the sand well enough, the ABS did not have enough oxygen to achieve combustion properly and the smoking continued. Back to the printer.

My second round of testing I received more of the results that I was looking for. First, I limited the amount of ABS in the print (no more than 5% fill) and I reused the sand that had dried from the first attempt. The first part, an android head, came out with good detail and only minor artifacts.

The android body did not do as well. I did not settle the sand well enough and the result was a compressed casting, something else to watch out for. I will be doing some more testing in the near future to refine my process and see how patterns with thin sections will turn out. Maybe a T.I.E Fighter Advanced will be the test for that.