Shell Molding

shell molding

[′shel ‚mōld·iŋ]
Forming a rigid, porous, self-supporting refractory mold by sprinkling molding sand blended with thermosetting plastic or resin over a preheated metal pattern and then curing in an oven.

Shell Molding


a method for the production of shaped castings from metal alloys in molds that consist of a mixture of granular sand (usually quartz sand) and a synthetic powder (usually phenol-formaldehyde resin and Bakelite powder). The use of clad grains of sand (covered with a layer of synthetic resin) is preferable.

Shell molds are made by one of two methods. The mixture is spread onto a metal pattern that has been heated to 300°C and held for a while, until a thin, hardened layer forms; the excess mixture is then removed. When using a clad mixture, it is blown into the space between the heated model and the exterior contour plate. Both methods require subsequent hardening of the coating on the model in a furnace at temperatures up to 400°C. The resulting shell half-molds are fastened together, and the liquid melt is poured into the mold. To prevent deformation of the molds when the melt is poured into them, they are placed in a metal jacket before casting, and the space between the mold and the jacket walls is filled with metal shot, whose presence also affects the temperature conditions during cooling of the casting.

Shell molding is used to produce castings weighing up to 25 kg. The advantages of this method are higher productivity than casting in sand molds, control of the mode of cooling of the casting, and the possibility of mechanizing the process.


References in periodicals archive ?
In the mid-90s, Osco Industries saw it would not be able to keep up with the organic growth of its customers with the existing single green sand casting facility (along with the shell molding plant), so it opted to build a second, new plant four miles away in New Boston, Ohio.
1) stainless steel cast parts by shell molding (25 Unit)
He concluded, "Recent exhibitors added to the online exposition, in addition to existing offerings, include nearly 50 suppliers of shell molding, no bake mold, manganese, investment, aluminum, Ni hard, zinc, Meehanite, sand and investment castings primarily from the United States and China, but not limited to such markets." Torres continued, "ArriveNEWS is committed to being the premier source for all kinds of castings for a broad range of industries custom made from virtually every available material offered in low, medium and high production quantities."
The final stop for the raw dough is one of six trough dumpers, where the dough is tipped onto a belt conveyor to the pie shell molding machine, where the actual pie shells are created.
For the frame shell molding, TowFlex fabric is cut into flat pattern plies using a computer-controlled automated cutting table.
For the frame shell molding, TowFlex fabric is cut into flat pattern plies by means of a computer-controlled automated cutting table.
For these two reasons, manifold makers throughout the world have increasingly embraced "shell molding," a process that uses vibration welding to assemble manifolds from two or more conventionally injection molded parts.
The Megashell Process is a ceramic shell molding and casting process.
of manufacturing space to its existing shell molding facility, with a portion of the addition devoted to thermal sand reclamation.
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It can handle green sand, no-bake and shell molding. It will clean aluminum, brass, bronze, ductile, gray, malleable, and steel castings.
However, engineers at Eagle Alloy, a steel shell molding facility, recently decided to determine the benefit of reducing the size of the gate area, challenging traditional methods.