Additive Manufacturing – What is it?

Posted January 17th 2017

Additive Manufacturing (AM), also known as 3D printing, rapid prototyping or freeform fabrication is a process in which layers of material are used to form three dimensional objects under computer control; opposed to Subtractive Manufacturing such as machining.

The use of AM with metal powders is a new and expanding industry, with the ability to now produce complex metal parts rather than just prototypes as before. This is enabling a design revolution in various sectors such as automotive, medical, tooling and energy among others. There are currently a wide range of metal powders being used in AM such as, Steels e.g. 316L, Nickel & Cobalt super alloys, titanium alloys & aluminium alloys. Many more powders are being developed including; copper alloys, magnesium alloys, precious metals and Tungsten alloys.

Using AM over more traditional production methods has the following benefits:

  • Reduction in waste (Net shape process) – In standard aircraft manufacture up to 90% of material can be cut away
  • Increased design freedom
  • Possibility of lightweight structures e.g. lattice designs
  • Potential for several parts to be constructed as one
  • Reduced assembly operations e.g. welding
  • Shorter production cycles
  • No other tools needed e.g. molds

However this new technology also has several limitations:

  • Only suitable for smaller parts up to 2-3kg
  • Not yet suitable for mass production; the current capability for smaller parts is around 25,000 parts per year
  • Design limitations – removable support structures can be required if an overhang is less than a 45° angle
  • Material type – it is not yet possible to use non-wieldable metals in AM
  • Porosity – can be some residual internal porosity
  • Mechanical properties – the parts tend to be inferior to those which are wrought

Additive Manufacturing – What is it?