AM technologies developed as a result of improvements in different sectors. As per other manufacturing developments, improvements in computing power and reduction in mass storage costs opened the way for processing the large amounts of data typical of modern 3D computer-aided design (CAD). A CAD based 3D model is the common starting phase of all AM processes and allows the possibility of mass customization, meaning that a single product can be produced in low quantities but at a cost-effective price.
For the last three decades, STL (Stereolithography) file format, created by 3D Systems has been the industry standard for transferring information between design programs and AM equipment. However, STL format can describe only the surface geometry of a three-dimensional object without any representation of colour, texture or other common CAD model attributes. Since 2012, a new format (the AMF Format) has been developed as to overcome STL limitations. The STL/AMT (III) file describes the external closed surfaces of the original CAD model and forms the basis for calculation of the “slices” transferred to the machine, which represent the third phase.
The fourth step in the table below refers to the effective manufacturing and includes the AM machine setup, the building and the removal of the product, which will then finally need post processing (ex. polishing) and adaptation to the final use.
Numerous technologies have been developed for Additive Manufacturing: originally for producing plastic prototypes using a point-wise laser scanning technique, Powder Bed Fusion processes – and specifically Selective Laser Sintering (SLS) - were among the first commercialized and represent today the leading technology for metal parts (IV). AM systems for metal parts are enjoying a strong development worldwide, as per Wohlers Report 2014 (V). : 348 of machines were sold in 2013, compared to 198 in 2012 with a growth of a remarkable 75.8% yty.
Other key technologies relevant for Metal AM are Directed Energy Deposition, Sheet Lamination and Binder jetting.