Research on Automatic Generation Algorithm for the Supporting Structure in FDM Process

According to the forming characteristics of FDM process in the Additive manufacturing, an algorithm for automatic generation of thin plate structure support based on the slice projection method is proposed. For the closed surface model (such as STL model, NURBS model), the algorithm uses slice projection method to automatically generate a series of crossed and parallel and spaced thin plates to provide external support. The algorithm reduces the computation problem from three-dimensional support area to the calculation of two dimensional support areas. The algorithm is stable and reliable, and the supporting structure has smaller volume and better stability. The supporting structure and part structure are independent to each other. Different path planning methods can be used for FDM path planning, and different materials can be used for the supporting structure and part structure. It is easy to dismantle the supporting structure in the postprocessing and greatly improves the flexibility of FDM process. Introduction The design of the supporting structure is one of the key technologies in FDM (Fused Deposition Modeling) process in the Additive manufacturing. When the parts have a suspended structure, it is necessary to have a supporting structure to support the suspended structure, otherwise collapse deformation will occur, which will leading to the failure of forming. The rationality of supporting structure has a great influence on the accuracy and efficiency of FDM parts, especially for large-scale building structures. At present, the most common supporting structures including complete supporting structure and incomplete supporting structure. For example, the unsintered material in the SLS process forms a complete supporting structure. In the FDM process, taking into account the removability of supporting structure, incomplete supporting structure is usually used. Incomplete supporting structures usually are tree-shaped, wall-shaped, gallows-shaped, etc. The wall-shaped and gallows-shaped supporting structures have good stability, but more consumables. Tree-shaped structure are few consumables, but poor stability[1-2]. The construction algorithms for supporting structure can be divided into two categories, one is based on the 3D model of closed surface structure, such as STL model and NURBS model, according to its geometric characteristics (such as the direction of the outer normal vector), the supporting areas are calculated and the complete or incomplete supporting structures are constructed[2-6]. The other is based on the two-dimensional slice contour model, boolean operation is used to calculate the supporting area of each layer and to construct a complete supporting structure [7-9]. In this paper, an automatic generation algorithm using thin plate supporting structure based on the slice projection method is proposed for the closed surface model (such as STL model, NURBS model). In the supporting direction of the solid model, the slice projection method is used to automatically generate a series of thin plates with longitudinal and horizontal parallel intervals, which are used to provide external support. The algorithm reduces the dimension of the calculation from three-dimensional support area to that of two-dimensional support area. The algorithm is stable and reliable. The supporting structure obtained is incomplete, small and stable. The supporting structure and part structure are independent to each other. Different path planning International Conference on Modeling, Analysis, Simulation Technologies and Applications (MASTA 2019) Copyright © 2019, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Intelligent Systems Research, volume 168