<title>Laser-assisted direct manufacturing of functionally graded 3D objects by coaxial powder injection</title>

Abstract

The overview presents the state-of-the-art in application of laser assisted Rapid Prototyping (RP) methods and their possibility to produce Functionally Graded Material (FGM) models. As Rapid Prototyping is a stepwise process constructing the object layer by layer, material composition may be changed from layer to layer and/or within the layer, this way a FGM object with 3D material gradient can be created. The free-form FGM model with engineered shape, composition, structure and even protective coating can be manufactured within one single process. Several techniques are analyzed and particular attention is paid to the lateral and coaxial powder injection into the laser beam. These technologies are shown as most effective tool for creation of FGM parts. The best results are obtained in laboratory conditions: spatial resolution of fabrication up to 200 μm with Ra up to 5 μm, transition zone between layers of different composition can be varied in a wide range starting from 10 μm.