Additive Manufacturing and Fabrication

Building up instead of cutting away

Additive manufacturing, better known as 3D printing, builds an object by depositing material layer by layer from a digital design, in contrast to traditional subtractive manufacturing, which starts with a solid block of material and cuts, drills or machines away everything that is not part of the final shape. That single reversal in direction, adding material rather than removing it, is what lets additive manufacturing produce complex internal structures (hollow lattices, internal channels) that would be difficult or impossible to cut out of a solid block, and what lets it produce a one-off custom part cheaply, since no separate cutting tool or mould has to be made first.

One process, a genuinely wide spread of real applications

3D printing's applications span a deliberately wide, and genuinely real, range worth knowing precisely rather than assuming the technology is limited to plastic prototypes. It has been used to manufacture confectionery and food items, printed for novelty shapes and precise portion control. Researchers have created bionic ear implants by 3D-printing a structure that combines biological tissue with embedded electronic components, an early example of the broader field of bioprinting. Automotive manufacturers use 3D printing to produce actual vehicle components, not only prototypes, taking advantage of the technique's ability to make complex, lightweight parts on demand. And surgeons use 3D-printed models and implants in reconstructive surgery, building patient-specific anatomical models from medical scan data to plan a procedure, or printing implants shaped to match a specific patient's anatomy exactly. None of these four applications is a hypothetical or future use; each is a real, already-demonstrated one, which is precisely why a question listing them tends to have "all of the above" as its answer rather than a subset.

Quick revision points

• Additive manufacturing (3D printing) builds objects layer by layer from a digital design, the reverse of subtractive manufacturing, which cuts material away from a solid block. This reversal is what enables complex internal structures and cheap one-off custom parts.
• Genuine, already-demonstrated 3D printing applications: confectionery/food items, bionic ear implants (an example of bioprinting, combining tissue with electronics), automotive components, and reconstructive surgery (patient-specific models and implants from scan data).