A rapid prototyping machine system which combines three axes PC-based controller with thermal extrusion method is presented. The main features of this system are to build up a physical object model through the extrusion of thin thermal plastic material and building it up layer by layer. User can use this system to turn CAD model into physical object model. Hardware design includes three axes working table, a thermal extrusion head, and a PC-based control system. The rapid prototyping system software includes CAD-model slicing process and 2D-layer cross sectional fill generation algorithms. The process begins with the design of a conceptual geometric CAD model of an object. The cross sectional STL format data is interfaced to the rapid prototyping machine system. The system can be extended to use other plastic materials from the thermal extrusion head and build up the model layer by layer.