GE Additive Centre in Ohio 3D prints parts for it’s aircraft engines ! Profound as that may seem, where reliability and caution in manufacture is paramount in the aerospace industry, it is today’s reality. In fact 35% of components in it’s Advanced Turbo Prop engine are 3D printed. Not just GE are moving in this direction, Airbus are making the largest ever 3D printed cabin component in the form of a partition wall that locates between the seating area and the gallery.

Advantages of 3D printing are: weight saving, zero material wastage in manufacture (compared with ~ 90% wastage for traditional methods), shorter lead times from design concept to finished operational part, and lastly but most importantly the  manufacture of complex parts that cannot be made any other way.

Materials that can be printed are: plastics, carbon, aluminium, titanium, stainless steel

3D printing is a collective term for a host of different additive manufacturing methods to make a part. A 3D CAD model is sliced up into layers – as thin as 20 to 30 µm. A machine then uses these to build up a 3D design. Methods fall into 3 different categories:

1. Direct Energy deposition – a nozzle pushes out a solid wire of metal, a laser beam shines directly on to material creating a focused melt pool on top of a substrate. Robots manipulate these to create 3D part.
2. Powder-bed electron beam melting – an electron beam focuses on a powder bed of material. As it moves the beam melts the powder forming a solid layer. Layers build and part is created.
3. Fused deposition modelling – most commercial – a nozzle heats up and deposits a thermoplastic filament to create the part in a number hours. A traditional method would take weeks.

Rightly though, some large companies are cautious, such as Rolls Royce, in adopting this technology for mission critical parts in their engines because mechanical properties are still suspected to be inferior to parts made from tried & tested manufacturing methods – fatigue stress in service is probably the highest concern. Potentially lives are at stake here and reliability is paramount, and any failures ultimately hit reputation and then share price.

Conversely though Siemens are 3D printing turbine blades for their gas turbines that run at twice the speed of aircraft engines at a temperature of 1250 °C ! Injury or fatalities due to a failure though, would be near to zero or limited in this case.

As the technology becomes more accepted & proven, I think we can expect more of our aircraft to be made from 3D printed components, producing lighter and less expensive aeroplanes !

Hope you have a good month

All the best

Mike

A little light relief

some more alternative exam answers …  !