[bergy]

OK - rainy day here & I just got off the phone with Mark B. Mark asked some questions about the foundry molding process, so I figured it best to post some info for the community. Conveniently, I had the pattern shop make up a gift for Jim McLernon (GM of all Chevrolet manufacturing) that I gave to him when he visited our plant. when I left Chevrolet - the plant gave me the same gift (a miniature cylinder block) along with the molds that it took to produce it. I dug them out & can use them for illustration.

First - the top (cope) and bottom (drag) halves of the molds were produced in "green" sand (silica sand bound together with bentonite clay & water). A container (flask) was placed over the pattern, and sand was automatically dumped on top of the pattern/flask assembly. Next, hydraulic squeeze heads compressed the sand/clay mixture against the pattern. When the flask was lifted off of the pattern, it contained a perfect impression of the pattern in the sand/clay material. Using my miniature parts - here's what the bottom mold and some of the cores that had to be set into the mold looked like: