Forming Principle and Principle Analysis of Lost Foam Casting

(1) The existence of solid mold cavities greatly simplifies the lost foam casting process, significantly improves the surface quality of castings, reduces equipment investment remarkably, and boosts production efficiency substantially. However, solid mold cavities also make the forming mechanism of lost foam castings vastly different from conventional cavity casting. This critically affects the internal quality of castings and becomes the primary cause of various casting defects. This section mainly analyzes the process characteristics of lost foam casting, as well as the forming process and mechanism of castings.

(2) Principle Analysis of Lost Foam Casting FormingThe greatest advantage of lost foam casting lies in the elimination of mold stripping, core setting and mold closing operations, which greatly optimizes process operation and improves production efficiency. Meanwhile, its biggest drawback also stems from solid patterns: they complicate the metal liquid filling process, resulting in diverse casting defects. In addition, negative pressure during pouring further intensifies the complexity of molten metal filling.Lost foam castings are formed as molten metal decomposes and vaporizes the foam pattern by heat, occupies the original position of the pattern, and solidifies into finished castings. At the advancing front of flowing molten metal, intricate physical and chemical reactions occur, with intertwined heat transfer, mass transfer and momentum transfer processes.