Laser assisted additive manufacturing process starts from the creation of 3D CAD model of desired part. This model is then sliced into layer. Manufacturing itself can be separated in two steps: 1) powder spreading and 2) building up desired shape from powder by solidifying it layer by layer with laser beam. By lowering the sintered layer and recoating the first layer with powder, second layer is then solidified by laser beam and then connected together with the previous layer. These two steps are repeated continuously to build the product layer by layer.
Advantages of laser assisted additive manufacturing are e.g. wide selection of powder materials including metals, ceramics and polymers, no need for additional structures for support, automation is very high, very complex shapes and parts are possible and often just as easy to make as simpler parts, rapid prototyping of products. Disadvantages of laser sintering are e.g. roughness of the surface and shrinkage of the work piece which might cause distortion and cracks. Accuracy of processing depends on the size of the powder particles (ranging from 0.05-0.35 mm).
Most often used lasers in laser assisted additive manufacturing are fiber laser and CO2-laser. Power range is from 30 W to 400 W. CO2-laser (wavelength 10.6 µm) has good absorption to polymers and fiber laser (wavelength 1.07 µm) is better for metals and ceramics.
Laser sintering