Printing has always been a manufacturing process that dates back to the invention of the first printing press by Johannes Gutenberg in 1440. However, today the printing is being done in three dimensions (3D) and it is predicted to fundamentally transform the nature of manufacturing.
Additive not subtractive manufacturing
Traditional manufacturing has been “subtractive” in nature. Machine tools take large pieces of metal or wood and then cut, drill or shave away significant portions of the original material to create finished parts. This produces substantial waste and most products must be made in separate parts and assembled.
Early manufacturing required highly skilled craftsmen who could make the finished product from end to end largely by hand with some assistance from tools. Industrialisation of manufacturing from the late 18th Century onwards shifted to semi-skilled labour and mass production. The ability to build machine tools and automated production lines helped to lower cost and produce goods in bulk, but at a standard of quality that was uniform.
Throughout the 20th Century the focus of manufacturing has been on how to design products for mass production at a cost and quality that is competitive. Total Quality Management (TQM), “Just in Time” and “lean manufacturing” focused on improving quality while lowering cost. Coupled with these concepts has been the notion of “agile manufacturing”, or the ability to quickly reconfigure the production line to produce customised products.
However, the most recent development has been the emergence of “rapid manufacturing” or what is also referred to as “additive manufacturing”. This employs the technology of 3D printing to rapidly create finished parts or even full products in a variety of materials. Unlike earlier subtractive techniques, 3D printing is additive because it adds layers of material that is usually fused together into a solid object. This process produces significantly less waste. It is also highly accurate in its assembly.
3D printing – from rapid prototyping to finished products to self-replicating machines
The first 3D printing was developed by Charles Hull in 1984 in a process known as stereo-lithography for which he secured a patent in 1986. These stereo-lithography apparatus (SLA) devices employ a UV laser beam to trace thin layers within a vat of liquid photo-curable polymers. As each slice is created a solid object is built.
These SLA were soon complemented with a series of alternative systems such as fused deposit modelling (FDM) and selective laser sintering (SLS). The FDM system employs a semi-liquid material (e.g. plastic) that is extruded from the printer head and builds the final object. The SLS system uses fine powdered substances (e.g. glass, aluminium, titanium, nylon) that are blown from the printer head and fused into a solid object via lasers.
The Massachusetts Institute of Technology (MIT) patented a 3D printer system in 1993 that employed a similar process to 2D inkjet printers. By the mid-1990s a series of industrial 3D printers were being sold and used in manufacturing, but in 2005 Z Corp launched the “Spectrum Z510” (see image below). This was a full colour, high-definition 3D printer capable of rapidly producing prototypes and models to a high level of accuracy.