The Historical Background of AM
The roots of the printing industry have been traced back by some researchers to Gutenberg around 1439. Later, Ottmar Mergenthaler invented the linotype line-casting machine during the industrial revolution. In 1872, The Hyatt brothers invented the injection molding method for polymer parts, which has been widely used by many industries (Figure 1). In 1903, Ira Washington Rubel invented the offset press for printing on paper. In 1978, Xerox and IBM presented the digital black & white printer into the publishing market. In 1993, digital color printers were presented by Indigo and Xeikon.
Figure 1: Examples of products manufactured through injection molding method.
In the 1940s, Numerical controlled (NC) machine tools were used in production processes in many different industries before Computer Numerical Controlled (CNC) machines were presented (Figure 2). In 1946, James Watson Hendry used the first screw injection machine. In 1979, Ross Householder used Selective Laser Sintering for the first time as the first AM technology in a patent. By 1980, the traditional drawing techniques with ink pens and transparencies were still used for designing processes by designers and engineers.
Figure 2: Numerical controlled (NC) machines.
The roots of modern AM trace back about 40 years. However, the early practices of AM go back to the 1800s in topography and to the 1900s in photosculpture. Blanther (1890) suggested a layered method for topographical relief maps. Perrera patented his method for making a relief map. His method cuts contour lines on sheets, stacks and pastes cut sheets to form a three-dimensional map. In the 1970s, Matsubara of Mitsubishi Motors worked on a topographical process that uses photo-hardening materials. “In this process, a photopolymer resin is coated onto refractory particles (e.g., graphite powder or sand). These coated particles are then spread into a layer and heated to form a coherent sheet. Light (e.g., mercury vapor lamp) is then selectively projected or scanned onto this sheet to harden a defined portion of it. The unscanned, unhardened portion is dissolved away by a solvent. The thin layers formed in this way are subsequently stacked together to form a casting mold”. At the same time, DiMatteo suggested that the same stacking techniques can be implemented to produce surfaces that would be difficult to produce by standard machining operations.
Along with the developments in topography, François Willème invented photosculpture technology in 1860. In his study, an object was placed in a circular room and photographed by 24 cameras simultaneously. Then, a silhouette of each photograph was transferred on a panel (Figure 3). After Willème's studies, Baese advanced photosculpture technology using light and water to expand the photograph (Figure 4).
Figure 3: Willème’s photosculpture.
Figure 4: Baese's photosculpture technique.
The first successful AM process was effectively a powder deposition method with an energy beam proposed by Ciraud in 1972. “To produce an object, small particles are applied to a matrix by gravity, magnetostatics, electrostatics, or positioned by a nozzle located near the matrix. A laser, electron beam, or plasma beam then heats the particles locally. As a consequence of this heating, the particles adhere to each other to form a continuous layer” (Figure 5).
Figure 5: Ciraud's Powder SFF process.
Hideo Kodama from the Nagoya Municipal Industrial Research Institute worked on a functional photopolymer rapid prototyping system. Kodama’s method produces a solid model manufactured by building up a part in layers as given in Figure 6.
Figure 6: Kodama’s product.
Herbert worked on a system that directs a UV Laser beam to a photopolymer layer by means of a mirror system on an x-y plotter. In his study, a Laser beam was applied on a layer, and each new layer was created by liquid photopolymer as shown in Figure 7.
Figure 7: Herbert's LASER beam system.
After all these developments and discoveries, 3D Printing was originally developed at MIT. After the 1990s, AM and 3D printing were employed and implemented in relevant manufacturing systems. AM was generated from the Rapid Prototyping era. The first commercial 3D printing technology, Stereolithography (SLA) by 3D Systems, was used to visualize the prototypes in a better way in design and marketing functions. Furthermore, the performance of the 3D printing resulted in producing functional prototypes to be used in fully functioning systems.
In Figure 8, we present a brief summary of the last thirty years of Additive Manufacturing as a way to present the modern history of this technology. It is especially interesting to see how much is expanding in the last years into many disciplines including aerospace applications.
Figure 8: AM Timeline with some of the most important milestones in the last 30 years.
AM has been used in various industries with a huge economic impact on today’s global business world. According to The Economist, a new industrial revolution may be on the way, led by AM.
We invite you to watch the following two videos, the first one is a short description of the modern history of 3D Printers and the second one a more comprehensive documentary about Additive Technologies, past, present and future. Some of the content included in these videos will be presented and expanded in following sections of this module.