US 12,350,735 B2
Lost foam and sand casting with polylactic acid- based foam articles
Saumitra Bhargava, Clarksville, MD (US)
Assigned to LIFOAM INDUSTRIES, LLC, Greer, SC (US)
Filed by Lifoam Industries, LLC, Greer, SC (US)
Filed on Sep. 28, 2023, as Appl. No. 18/476,909.
Claims priority of provisional application 63/386,676, filed on Dec. 9, 2022.
Prior Publication US 2024/0189888 A1, Jun. 13, 2024
Int. Cl. B22C 7/02 (2006.01); B22C 9/04 (2006.01)
CPC B22C 7/023 (2013.01) [B22C 9/043 (2013.01); B22C 9/046 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A method for forming a metal article, the method comprising:
producing a foam casting mold, wherein producing the foam casting mold comprises:
producing expandable foam beads formed from polylactic acid,
molding the expandable foam beads into a foam article having a first shape, wherein the foam article corresponds to the metal article,
drying the foam article,
conditioning the foam article, and
exposing a surface of the foam article to heat and pressure to form a skin from the expandable foam beads on the surface of the foam article to form the foam casting mold;
investing the foam casting mold in sand;
casting molten metal into the invested mold;
removing the cast metal from the sand; and
treating the cast metal to produce the metal article.