Additive Manufacturing What is it?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