Electron Beam Melting (EBM)
Electron beam Melting (EBM) is a technique that consists of preheating and then fusing together thin layers of metallic powders using an electron beam to obtain a part directly from its 3D model. A magnetic field focuses the beam to the desired diameter and another magnetic field is used which directs the electron beam to desired coordinates on the print bed.
The working principle is basically the same as Powder Bed Fusion technology. It is a hot process, during which the powder is kept at high and constant temperatures throughout the melting process. The fusion beam is concentrated, accelerated and directed towards the powder with a particle size of 45-80 µ, it offers a more concentrated fusion power than the laser beam and can easily reach temperatures between 700 ° C and 1400 ° C, or even beyond. The parts should be produced in a vacuum chamber. The fusion by electron beam provides a high productivity and a greater freedom of forms, particularly for components with lattices structures.
With EBM technology, components can be produced from materials that are difficult to melt by traditional methods such as titanium Aluminide (Ti-Al), titanium-niobium alloys or other elements. EBM is a lot faster as compared to SLM/DMLS because of the high energy density of the electron beam. The components produced by electron beam melting are not subjected to residual stresses and tensions. They can be immediately used for processing or mechanical assembly. The parts obtained have very good strength properties because of the even temperature distribution in the part during its fusion and building process. CNC machining, sandblasting, plating, electro polishing are some of the post processes that can be used to refine the final part.
Advantages of EBM
• Very less lead time.
• Energy efficient compared to Laser-based technologies in Additive Manufacturing.
• High standard parts used in airplanes are manufactured.
Disadvantages of EBM
• Process requires significant amount of validation.
• Post process is mostly required.
• Machines need a high level of maintenance.