3D printing has eliminated much of the tedium of the 3,000-year-old sand casting process
Excerpt from the September 2020 The Additive Report article by Kip Hanson.
Humans began pouring the first sand castings approximately three millennia ago. And until recently, that technology has remained virtually unchanged:
• A replica, or "pattern," of the desired object is placed in an open-ended, steel molding box.
• A special type of sand is poured around the pattern, which is pounded firmly into place and then removed.
• A sprue is cut to allow molten metal to flow into the mold, along with a gate that joins the sprue to the mold cavity.
• A core is used to replicate parts having internal features.
• Molten metal is poured into the mold; when the metal cools, the completed part is removed.
That's sand casting in a nutshell, although journeyman pattern maker Dave Rittmeyer will tell you there's far more to it than that. Rittmeyer, the customer care and additive manufacturing manager at Hoosier Pattern Inc., Decatur, Ind., also will tell you the industry has undergone a dramatic shift over the past decade or so, thanks in part to AM.
