At the stage of initial design, prototypes are needed for engineering and aesthetic purposes. In order to get a fast and non-expensive prototype, designers prefer rapid prototyping(RP) to any other means. In driving a 3D CAD model into rapid prototyping, sectioning the model is essential and there are two negotiation-needed targets, enhancing accuracy while taking less build-time, which makes adaptive slicing taken into account. In spite of the advantages of adaptive slicing, it is not yet applied to real RP machines because of the limits of hardwares. In this thesis, a new slicing algorithm which (1)uses several values of thickness available in a RP machine. (2)determines total number of layers to make the prototype within the intended time and (3)arranges the layers using orthogonal arrays to minimize the volume error caused by the difference between a given CAD model and a fabricated model is presented. And the algorithm is expected to have possibility of assisting RP machines to take the advantages of adaptive slicing.