The pattern halves are removed and the mold is assembled with or without cores. Better as-cast surfaces. Improved dimensional repeatability Less skill and labor required then in conventional sand molding. Better dimensional control. Disadvantages Sand temperatures critical.
Patterns require additional maintenance.
Pattern halves are bonded together with or without cores. Ejector pins enable the mold to be released from the pattern and the entire cycle is completed in seconds depending upon the shell thickness desired. The two halves of the mold, suitably cored, are glued and clamped together prior to the pouring of the metal. Shell molds may be stored for long periods if desired. Because of pattern costs, this method is best suited to higher volume production.