Introduction: Rapid prototyping is the techniques used to quickly fabricate patterns and designs using three dimensional computer aided design (CAD). The castings that are then made using investment casting; sand casting and plaster molding method are useful to visualizing and testing the properties of the final cast products.

Various rapid prototyping method are used that better communication between the engineering department, the manufacturers and the clients. In recent years, rapid prototyping casting has received gaining wide spread recognition. In a survey conducted among 90 die casters, it was found that 30% of them were involved in protyping or short-run die casting.

Process: 3-D CAD patterns are made on a computer using the prints or solid modeling provided by the customer, which is converted into STL file. The file is then printed three-dimensionally using photopolymer, thermo polymer, polystyrene and other materials depending upon the rapid prototyping method. The prototype patterns are attached with gating system and processed through different casting methods to produce prototype parts. Patterns that are made of rubber or other materials are then used to fabricate sand or plaster molds. Metals for casting like aluminum and zinc are poured into the mold, to generate prototype parts.

Types of Rapid Prototyping

• Stereolithography (SLA): Parts are produced by laser curing of an epoxy resin based photopolymer.
• Selective laser Sintering: SLS is a cost effective solution for durable and functional parts with end-use performance properties, although the surface finish of the casting may not as perfect as the original products.

Why Rapid prototype cast? When a die casting is made, it is sometimes found that the final product may not be as perfect as it was intended. This may be because of the variety of operations that are done during the casting process. Or, in some instances the final product may fail to impress the customer. It is therefore beneficial to first simulate the final product using low cost rapid prototyping and low volume production runs.

Application: Rapid prototyping enables is generating prototypes of casting that will help in checking the final product for design flaws and other problems. Aluminum, magnesium, and zinc prototypes can be made regardless of the complexity of the design of casting.

Advantage:

• Eliminates design and other problems in castings
• Increases effective communication between the manufacturer and the customer
• Decreases costly mistakes.