Automatic Determination Of Part Build Orientation For Fused Deposition Modeling

Fused deposition modeling(FDM)is one of the cheapest and most commonly used additive manufacturing processes.In FDM,the build orientation is one of the key factors affecting the quality of the printed part.However,determining the build orientation of FDM parts often relies on the knowledge and experience of experts in the field.Considerable progress has been made in the study of forming direction selection,but then the use of ontology methods suffers from the following shortcomings when making multi-criteria decisions on printed parts: slower;less stable generated results;inability to be used for complex smooth surfaces;and inability to perform automatic capture and inference representation.This requires a method that can capture,represent,reason about and automatically determine it.This paper presents a study of an FDM-oriented method for the automatic determination of the build orientation of a part,with the following main work and results.(1)An FDM-oriented method for the automatic generation of alternative build orientations for parts has been developed.The method uses a facet clustering method to automatically generate alternative build orientations,dividing the part model into a large number of triangular facets by a facet clustering algorithm,from which a certain number of alternative facet clusters are automatically generated,and the alternative build orientations of the part are obtained based on the unit normal vectors of the facets.(2)A comprehensive estimation model of the five influencing factors of the part is constructed.Five factors that may affect the accuracy and quality of the part are considered,namely support structure volume,surface roughness,volume error,forming time and manufacturing cost.Based on the part model and the type of support,etc.,an estimation model for the support volume and volume error of the part is built;an estimation model for the surface roughness of the part is built based on the print path,printhead size and print speed,etc.;and an estimation model for the forming time and manufacturing cost of the part is built based on the support volume,print speed,material unit price and post-processing unit price,etc.(3)A three-way multi-criterion decision-making method for optimal orientation selection of FDM parts is designed.The three-way multi-criterion decision-making method is used to automatically determine the optimal build orientation of the part from alternative directions.A multi-criteria decision-making method(MCDM)is used to solve the problem of integrated consideration of multiple factor values.The vast majority of decisions are currently achieved by two-way decision making,so a multi-criterion three-way decision making method is developed to introduce the flexible features of three-way decision-making into the MCDM.(4)A description logic(DL)ontology-supported method for automatic orientation of FDM parts is proposed.Determining the build direction of FDM parts currently usually relies on the knowledge and experience of domain experts,the proposed method is able to solve this problem by capturing,representing,reasoning and reusing data and knowledge in the process.First,a set of top-level entities is created to build a DL ontology for FDM parts.Then,a DL ontology-supported alternative orientation generation process,a DL ontologysupported factor value prediction process and a DL ontology-supported optimal orientation selection process are developed successively.(5)An FDM-oriented algorithm for automatic determination of part build orientation is developed.The code for the method was developed using MATLAB and Python.The method was validated by simulation with six models of simple and complex models of freesmooth surfaces,and printing experiments and comparison experiments were conducted to demonstrate the superiority of the method.The demonstration results show that the proposed method is satisfactorily effective and efficient.