Choosing the best prototype material for your particular product or invention depends on a number of factors including budget, presentation, time frame, and quantity. The final function of a prototype part or product usually determines the material from which a prototype is made. Building a working prototype may be as simple a cobbling together some simple materials or items found around the house. The materials used in rapid prototyping (RP) can provide a more detailed prototype needed for presentation to investors, engineers, marketers, designers, or manufacturers. Other prototype material includes patterns made with silicon molds and various types of plastics or combinations of resin and other materials.
Initially, prototype material may be wood, clay, resin or a combination of these and other materials. Consider cost before deciding what prototype materials or processes will be used. Some of the most successful products have initially been made from very crude prototype materials or items found around the house, like cardboard, wire, and duct tape. As long it shows how the product works, any type of material can be used for a prototype. One type of inexpensive prototype material is a special plastic that becomes soft and moldable when heated in a microwave or with a hairdryer.
Rapid prototyping uses a technique called stereolithography (SLA) to create tangible prototypes from a computer-aided design (CAD) drawing. The prototype material used in this process is a liquid resin which is roughly formed using ultraviolet laser radiation and cured in an ultraviolet oven. The finished SLA prototype is then finished by hand to meet the designer's specifications. These SLA prototypes look and function like the real thing and provide a hands-on, working model of the finished product, ready for presentation. The biggest advantage to using these resin materials is the quick turnaround and the low cost of even multiple design iterations or revisions.
Silicon molds and liquid plastic are probably one of the most cost-effective of all prototype materials when only a small number of prototypes are needed. Referred to as room temperature vulcanization (RTV), this process uses an RP model to create a master mold from silicone rubber. Liquid silicone is poured around the RP model or master pattern to create a negative mold. This process is best suited for prototypes that are needed in a short amount of time. The finished prototype material is usually a combination of two-part polyurethane, wax, and silicone rubber.