Vacuum Casting Service: 5-100 Custom Plastic Parts with Silicone Molds

Vacuum casting is a versatile manufacturing process that produces high-quality plastic parts in quantities ranging from five to one hundred units. The process uses silicone molds that accurately capture surface details from a master pattern, making it ideal for bridging the gap between 3D printed prototypes and injection molded production parts.

The vacuum casting process begins with creating a master pattern, typically produced using SLA 3D printing due to its excellent surface quality and dimensional accuracy. This pattern is placed inside a container, and liquid silicone is poured around it. After the silicone cures at elevated temperature, the pattern is removed, creating a cavity that exactly replicates the original geometry. The silicone mold can typically produce twenty to fifty parts before needing replacement.

Two-part polyurethane resins replicate the mechanical properties of production thermoplastics including ABS, polypropylene, polyethylene, and nylon. Material selection depends on the required stiffness, impact resistance, heat resistance, and surface finish of the final part. Colorants can be added during mixing to achieve specific colors, and surface textures can be replicated from the master pattern.

Typical dimensional tolerances for vacuum cast parts range from plus or minus 0.1mm to plus or minus 0.3mm depending on part size and geometry. Wall thickness can be controlled between 1.5mm and 6mm in most cases. Draft angles of one to two degrees facilitate part removal from the mold, though undercuts can be accommodated with more complex mold designs. The process handles complex geometries with internal channels and recessed features that would be impossible to produce with conventional machining.

Lead times for vacuum casting typically range from five to fifteen business days depending on part complexity and current capacity. The process is significantly faster than injection molding tooling, which can take eight to twelve weeks to produce. For functional testing, market validation, or small-batch production, vacuum casting provides an economical solution that closely approximates the appearance and properties of injection molded parts.