Investment casting (IC) can be a very economical method of producing metal parts in a rapid prototyping scenerio. Parts with undercuts, thin walls, or complex core features often times can only be produced with an IC process. Modern Cam has worked with a foundry knowledgeable in using Fused Deposit Model (FDM) parts made in ABS plastic usiing our Stratasys, Inc. Dimension 3D printer.

The traditional  IC foundry creates wax patterns made from machined aluminum tooling . For small quantities, the tooling cost of the aluminum molds can be expensive to machine and carry a long lead time to produce. An alternative approach to making a wax pattern is to create a pattern directly from the printed ABS plastic model. For small quantities, the advantage of using an ABS model vs. tooling is cost and time.

 Modern Cam produced a replica of a carburetor bowl taken off a 1938 John Deere tractor by reverse engineering it using our PCMM, CAD software and Stratasys 3D printer. The original bowl was cracked, John Deere no longer supplies replacements, and as a project to perfect our reverse engineering skills and gain experience with IC and ABS models, we produced a replacement casting after working with our local foundry source.

The actual ABS model that we submitted to the foundry was modified using our CAD package to account for a shrinkage factor and the finished features that were machined into the part afterwards (eg. the tapped holes). Stock was also left to machine gasket surfaces on the bowl as well. The result was a virtually identical reproduction, completely functioning , cast iron part . This whole process was done in two weeks-begining to end.