Net-Shaping of Ceramic Components by Using Rapid Prototyping Technologies

The application of rapid prototyping (RP) in ceramics was motivated by the advances in engineering ceramics and traditional ceramics where methods of creating complex shapes are limited (Cawley, 1997). Ceramics have many outstanding physical and chemical properties and attract lots of researchers’ attentions to find new industrial applications for this kind of material such as components resistant to the high temperature, piezoelectric sensor and actuators (Safari et al., 2006; Miyamoto, 2004). But ceramics often cause high machining costs for products in limited quantities and high tooling costs in injection molding of large batches. Moreover, ceramic components with complicated structures cannot be shaped by the conventional forming processes such as casting, forging and machining. High temperature ceramics are also hard and difficult to machine. Even for the simple geometries which can be produced by the traditional fabrication process, the time needed for the mould preparation drastically enlarges the period between the design and the first prototyping verification of the new production. Industrial applications of ceramic materials especially for the jobbing work and complicated components are largely restricted by the lack of the net-shaping capability for the components with complex structures. Rapid prototyping came into being at the end of last century when the first Stereolithography Apparatus (SLA) was invented as the first RP machine in 1984 by 3D Systems (Hul, 1984). It begins with a CAD model, usually a solid or a surface model which can be designed by the users. The CAD model is imported into the rapid prototyping system in which there is special software slicing the solid model to define a group of layers. The layer information including the process route, parameters and material properties is read by the computer. A computer controlled laser scanner realizes the laser scanning process to form each layer according to the respective layer information. Since the object grows layer by layer, it is possible to realize material and process combinations which are impossible to achieve with conventional methods. The general purpose is just to make prototypes in order to reduce the time of products development by shortening the period between design and test and then cut the development cost of new products. In recent years a pronounced method diversification has resulted in a large variety of different rapid prototyping techniques allowing for the generation of prototypes made of polymers, metals and ceramics. Now functional components, specially using metal or