Determination of optimal build direction in rapid prototyping with variable slicing

Several important factors must be taken into consideration in order to maximize the efficiency of rapid prototyping (RP) processes. The ability to select the optimal orientation of the build direction is one of the most critical factors in using RP processes, since it affects part quality, build time, and part cost. This study aims to determine the optimal build-up direction when a part is built with the variable layer thickness for different RP systems. The average weighted surface roughness (AWSR) that is generated from the stair stepping effect, the build time, and the part cost using the variable layer thickness are all considered in the process. Using the multi-attribute decision-making method, the best orientation is determined among the orientation candidates chosen from the convex hull of a model. The validity of the algorithm is illustrated by an example. The algorithm can help RP users select the best build-up direction of the part and create an efficient process planning.