The history of additive layer manufacturing
Additive layer manufacturing has its roots in the development of Rapid Prototyping in the 1980s.
Rapid Prototyping (RP) originated in the United States and was first commercialised in the late 1980s. A process called Stereolithography (SL) solidifies thin layers together, using an ultraviolet (UV) curable thermoset polymer liquid with a solid state crystal laser to create the required geometry layer by layer, using Computer Aided Design (CAD) data.
This started the development of different RP processes which came to market during the early 1990s. Processes included Laser Sintering (LS), which consolidates thin layers of thermoplastic powder by heating it to a few degrees below the material's melting point, then using a carbon dioxide laser to fuse scans of the sliced CAD data to create the required geometry.
Another process is Material Deposition Extrusion, where material is heated through an extrusion nozzle and then follows a predefined deposition path, layering the material on top of the previous path to create the 3-dimensional geometry.
By the middle of the 1990s another process, 3D printing, was in development. 3D printing works by laying down thin layers of heated material onto a platform. Either the head or platform will be continuously in order to deposit more material on top of each other to form the 3D object.
Through the rest of the nineties further research and developments in material were undertaken to enable ALM technology to be used in more sectors and applications as demand grow. These developments were mainly focused around the different range of thermoset, thermoplastic, and elastomeric polymers in different forms.
As the new millennium began focus shifted back to improving ALM processes through development in a new generation of systems. This in turn allowed further materials to be developed, including the development of metals within ALM.
Over subsequent years more and more ALM businesses appeared from all over the world, starting to develop their own systems and materials. Many new types of systems and materials became available as the popularity of the technology grows. The industry realised that these processes were not just for RP applications, but developed and applied correctly could become a new form of manufacturing. Thus from this the name “Additive Layer Manufacturing” was born.
In the mid 00s metallic ALM processes, which produce fully dense metallic geometry, became available. One process, called Laser Melting (LM), was developed using the knowledge and understanding from SL and LS processes. New power sources started to be used, bringing about the Electron Beam Melting process which builds within a vacuum.
From this point various ferrous and non ferrous alloys are now either available or being developed. The EBM and LM processes started the development of the blown powder and wire extrusion for metals. Powder and wire feed processes enable new applications and allow systems to be scaled up.
Further developments in the LS process are now capable of processing high temperature thermoplastic powder, which because of its melting temperature has not been possible before.
Within the last five years with the new materials and advances in system developments, industry from all sectors have now realised the potential of using these types of processes to further develop their own products to enable cost savings, new optimised designs, and support their own manufacturing methods and expertise.
Work continues across the world on the international standardisation of processes and materials, industrialising the systems, and preparing the supply chain for potential demand for products using these processes.