Electron Beam Powder Bed Fusion
Electron beam powder bed melting is a high-vacuum melting process where metal powder is melted layer by layer with a high-energy electron beam. This reduces thermal stresses and allows processing of reactive materials.
Physicochemical mechanism of action
A high-energy electron beam is fired at metal powder in a vacuum. The beam's energy detaches the atoms of the powder and forms a liquid melt phase. Since the process takes place in a high vacuum, there is no air or other gases to react with the metal, which minimizes thermal stresses.
Metallurgical relevance & risks in welding
This process is particularly useful for processing hard-to-melt or reactive materials such as titanium or cobalt alloys. It prevents thermal stresses that could lead to cracks and deformation. However, it requires high precision in beam energy and powder distance to ensure a homogeneous structure.
Workshop practice & action instructions
To perform electron beam melting in a powder bed, the equipment must be placed in a highly evacuated chamber. The metal powder is layered and fired with an electron beam typically at 10 to 50 kV. Process time varies by material but is usually between 30 seconds and a minute per layer. It is crucial to precisely regulate beam energy and powder distance to achieve a homogeneous and finely structured part.