About Metal 3D printing...
Metal 3D printers, also known as
metal additive manufacturing machines, use a layer-by-layer approach to create
three-dimensional objects from metal powders. The working principle of these
machines involves several key steps:
Digital Design: The process begins with the creation of a 3D computer-aided design (CAD) model of the object to be printed. This digital model serves as the blueprint for the metal 3D printer.
Slicing: Specialized software takes the CAD model and slices it into thin horizontal cross-sectional layers, often referred to as "slices" or "layers." These slices determine the toolpath and the shape of each layer that the printer will create.
Printing Preparation: The 3D printer operator loads a bed or build platform, typically made of metal, and applies a thin layer of metal powder (usually the same material as the final part) evenly across the platform. The thickness of this layer is precisely controlled and corresponds to one of the sliced layers from the CAD model.
Layer Deposition: The metal 3D printer employs one of several methods to selectively fuse or solidify the metal powder for each layer based on the design:
Selective Laser Melting (SLM): A high-powered laser scans the cross-section of the part, melting and fusing the metal powder in the desired areas. As the laser moves, the metal powder solidifies, creating a single layer.
Electron Beam Melting (EBM): Instead of a laser, an electron beam is used to melt and fuse the metal powder. EBM is typically used for specific materials like titanium.
Binder Jetting: In this method, a liquid binder is selectively jetted onto the metal powder layer, effectively glueing the particles together in the desired pattern. After each layer is completed, a new layer of metal powder is spread, and the process is repeated.
Direct Energy Deposition (DED): DED systems use a nozzle to deposit a metal powder feedstock (usually wire or powder) and a high-energy heat source (often a laser or electron beam) to melt the material and build up the part layer by layer.
Layer-by-Layer Building: Steps 3 and 4 are repeated for each subsequent layer, with the build platform moving down (or in some cases, the print head moving up) to accommodate the new layer of metal powder. This layer-by-layer process continues until the entire 3D object is complete.
Cooling and Solidification: As each layer is deposited and fused, it cools and solidifies. This gradual solidification ensures that the metal part retains its structural integrity.
Post-Processing: After the printing process is complete, the metal part often requires post-processing steps such as heat treatment, machining, and surface finishing to achieve the desired mechanical properties and surface quality.
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