There are also different types of AM, the most common in use today is known as Fused Deposition Modeling. In this method, plastics, polymers, or even cement, is very carefully ejected from a nozzle to build a layer of the object. As each layer dries, a new layer is placed on top of the previous one, building up the three-dimensional shape one very thin layer at a time. This method of AM was developed in 1988 by S. Scott Crump and his company Stratasys.
Visual example of fused deposition modeling
Another common method of printing, and actually the oldest, is known as Stereolithography, a process by which a vat full of liquid polymer or resin is hit by very precise beams of ultraviolet light. The UV energy causes the polymers to bond to each other and form a solid, and the device uses this method to create thin layers of solid polymer built upon one another to create the desired object. Modern Stereolithography was invented in 1981 by Japanese researcher Hideo Kodama though the process was further refined by researchers in France and the US. It was American researcher Chuck Hull who coined the word Stereolithography when he filed for a patent in 1984 for his device that uses that technology.
Visual example of Stereolithography
The term 3D Printing originally referred to a single type of AM that utilized powder beds and inkjet print heads that resembled regular printers, hence the name. This is now referred to as a “Dot-on-Dot.” A bed is filled with a layer of powdered plastics or polymers. Precision inkjet nozzles with a binding agent sprays a pattern into the bed, which binds the powder into a solid. A new layer of powder is added and the process is repeated until the object is finished. This process was developed by MIT in 1993 and later commercialized.
The newest process is for metal sintering, that is, using AM to manufacture metal objects. There are various methods of sintering that are too long for this blog post, but the end result is creating metal objects in a similar fashion to the other methods discussed here. These processes were developed in the 1990s by researchers at Stanford and Carnegie Mellon, but it wasn’t until the 2010 onward that metal components created using AM processes were used in high stress parts like engines, brackets, and large nuts.