Prototype milling is a machine production process used to construct prototypes for design projects. The process involves cutting a prototype model from various materials using a three-dimensional computer numerical control (CNC) milling machine. These machines consist of a high-speed machine head capable of three-dimensional movement equipped with a chuck into which a series of cutting tool bits are inserted. The head moves over a block of model material, gradually removing layers from it until the finished prototype is revealed. The prototype milling process is controlled by one of various computer aided design (CAD) programs on which a digital model of the prototype has been drawn up by the design team.
Prototyping is a product design process where models of a proposed product are constructed prior to final acceptance of the product. This is a critical part of the design process that can save a significant amount of time and money during development of the product. Prototype models are built to include varying levels of functionality, allowing designers to assess the product and to demonstrate it to investors and the target market. Prototype milling is one of the processes commonly used to produce these models. It is known as a subtractive modeling method, as material is removed, or subtracted, from a block of modeling medium to produce the model.
The prototype milling process is carried out by sophisticated three-dimensional CNC milling machines controlled by CAD programs. The process begins with the development of a three-dimensional digital computer model of the product. This model is used by a sophisticated CNC milling machine as a map to control its movement during the milling process. The machines feature agile machine heads driving high-speed cutting bits that faithfully follow the profile of the computer model, slowly cutting away layers from a block of modeling material to reveal the finished prototype.
Materials used for prototype milling vary, but typically include various grades of epoxy resin, high-density foam, or metals. Wood and specially-designed laminate sheets are also used in the production of prototype models. The choice of modeling material generally depends on the intended level of detail and the functionality that the prototype is intended to exhibit. In some cases, the milled product will not be used as a prototype at all, but rather as a positive plug to create accurate molds utilized to produce high-quality castings of the final prototype.
