V-process casting and lost foam casting share common features: they use dry sand, vacuum pump suction, a vibrating table to compact the dry sand mold, and plastic film to seal the sand box, forming a sand mold with a pressure difference between the inside and outside for compaction. V-process casting has a cavity, while lost foam casting has a solid cavity—the foam pattern serves as the solid cavity, which disappears after molten metal is poured in.