Net shape manufacture

Rolls-Royce are actively pursuing the development and application of Net Shape Technologies, targeted at the manufacture of component shapes as close as possible to the finished part.  These technologies can realise some significant cost and lead-time reductions, compared to traditional manufacturing routes, characterised by:

• More efficient use of raw material, resulting in a lower ‘buy:fly’ ratio
• Avoidance of high levels of machining
• Increased freedom to modify component designs

Some specific Near Net processes that are being actively developed by Rolls-Royce and their extended partnership network are:

Powder Hot Isostatic Pressing (HIP) – where metal powder is contained within a mild steel canister that relates to the finished shape of the part. The canister is then subjected to high temperature and pressure, which results in compaction of the powder into a solid metal with near net shape. The technique is particularly suited to making large complex parts.

Blown Powder – where a laser spot forms a molten pool in substrate material, into which a stream of powder particles is injected by a flow of carrier gas. The substrate is moved relative to the laser spot, forming a track of deposited metal which can build up a 3D shape. The technique is particularly suited to the repair of engine components.

Powder Bed – where a thin layer (typically 20 microns) of powder is spread over a baseplate.  A small, high-energy dense laser or electron beam spot is rastered over the bed, which then fuses the powder into a solid metal lamina. The process is repeated layer by layer, until a 3D shape is produced. The technique is particularly suited to making small complex parts, which require high precision of deposition.

Metal Injection Moulding (MIM) – where a mixture of metal powder organic binder is compressed in a mould to form a green shape. This is then fired in a furnace to burn off the binder and fuse the metal powder into the solid part. The technique is particularly suited to making large quantities of small parts.