Terry Wohlers is the President, Founder and Principal Consultant of Wohlers Associates Inc., an independent consulting firm that works closely with manufacturing organizations to identify the best approaches to rapid product development and additive manufacturing. Additive manufacturing (AM), also referred to as additive fabrication, is a process of joining materials to make objects from 3D model data, usually in successive layers, as opposed to subtractive manufacturing methodologies. The parts produced can be models, prototypes, tooling components, and increasingly, series production parts. They are generated from 3D computer-aided design (CAD) data, medical scans, or data from 3D scanning systems. Based on thin horizontal cross sections taken from a 3D computer model, AM systems produce plastic, metal, ceramic, or composite parts, layer upon layer. The Wohlers Report 2009 shows that the global market for additive manufacturing grew to an estimated $1.183 billion in 2008. According to studies that have been conducted, it is expected that the AM industry will more than double by 2015 in total machines sold annually. 3D printing technology is the fastest growing segment of additive manufacturing. Seventy-eight percent of rapid prototyping systems installed in 2008 were classified as a 3D printer. This AM technology is typically more affordable, easier to use and office friendly. Three market segments make up the principle uses of AM technology. The largest is consumer products and electronics which include handheld devices, followed by motor vehicles and finally the medical and dental industry.