What is near-net shape?
Near net shape is a layer-additive process, which is used to build parts using a controlled high energy electron beam to melt a pool on the substrate whilst the wire feed system adds material to build up the required part.
The electron beam provides the energy source used for melting metallic feedstock, which is typically wire (powder can also be used). The electron beam is a highly efficient power source that can be both precisely focused and deflected using electromagnetic coils at rates well into thousands of hertz.
How does near net shape work?
With near net shape, the feedstock material is fed into a molten pool created by the electron beam. Through the use of CNC, the molten pool is moved about on a substrate plate, adding material just where it is needed to produce the near net shape. This process is repeated in a layer-by-layer fashion until the desired 3D shape is produced.
What are the advantages?
A major advantage of using metallic components with electron beams is that the process is conducted within a high vacuum environment of 1×10-4 mbar or greater, providing a contamination-free work zone that does not require the use of additional inert gasses commonly used with laser and arc-based processes.
- Parts are 100% dense and structurally sound without moulds or tooling
- Intricate, complex geometries can be made in a single operation whilst minimising scrap and manufacturing time
- Metal feedstock can be wire fed or powder
- Electron beam outperforms lasers with higher integrity coupling and better deposition rates
- Reduces scrap material wastage
- Final machining time reduced
Figure 1. Near Net Shape
Figure 2. Near Net Shape