When comparing the merits of rapid prototyping (RP) and CNC machining, opinions abound. RP and CNC machining both have staunch supporters that tout the benefits of their preferred technology.

However, those who are familiar with both technologies generally agree that each has its own merits.

In the past 15 years, prototype development has changed significantly. In the early days, most RP technologies offered an obvious speed advantage, but were limited by accuracy and material property issues. Since the launch of RP, CNC has advanced, in part due to the competitive threat, to become faster while offering many well-known benefits. Likewise, RP has improved in areas such as accuracy, material properties and surface finish. As the technologies come closer in capabilities, the selection process becomes increasingly difficult.