Research On Metaheuristic Algorithms-based Toolpath Planning And Optimization Of Additive Manufacturing

In recent years,Additive Manufacturing(AM)has been widely used in many fields such as aerospace,automotive,medical and educational industries.However,the processing of fabricating workpiece by AM is by means of layer by layer from bottom to top.The tool path has great impact on the precision and efficiency of manufacturing process.For those workpieces with hole-structure,the forming tool in the process needs to transfer a long distance in each layer,which is wasting time and energy.Therefore,reducing the unnecessary non-filling tool path in the process of manufacturing is of great significance to improve efficiency and save energy.This thesis proposes a three?dimensional tool-path planning algorithm which is combined with Metaheuristic?algorithms.Meanwhile,part splitting recognition and aggregation algorithms,interference detection and adaptive layer-level lifting algorithms are proposed to assist the three-dimensional tool path planning.These algorithms are able to realize the tool path planning and optimization of a non-filling tool path for AM,and to solve the problem of the large number of non-essential non-filling paths in traditional AM routes.The research content of this topic is as follows:1.There is a problem of having no mature and reliable visualization tool for AM which do not meet the requirements in display effect,data displaying and interactive operation at present.To solve this problem,this thesis develops a stable,reliable and fast visualization tool based on the VTK library to complete the task of path visualization with data statistics,and facilitate the study of AM path planning.2.For the traditional AM route planning method,there exists the problem of non?essential non-filling plane transfer path,and a three-dimensional path planning algorithm combined with metaheuristic algorithm for path planning is proposed.The algorithm preferentially selects the air toolpath in the Z direction to reduce the transition between the filling paths in the plane,and employs the metaheuristic algorithms to the air toolpath planning to realize the planning of the three-dimensional path.The experimental results show that this algorithm effectively reduces a large amount of unnecessary empty paths,and effectively increases the efficiency of AM processes.3.For the situation of using the metaheuristic algorithms directly to calculate the toolpath,the computation scale is too large,the calculation time is too long and the planning effect is not good.Based on the local continuity and dependency of the model,a subpart identification and aggregation algorithm using centroid matching of island polygons and graphical coincidence matching.Experimental results show that the algorithm effectively and accurately identifies and aggregates the isolated polygons belonging to the same subpart of the model.It makes a significant reduction in the computational scale of the three-dimensional path planning.4.There is a potential interference between the forming tool and the part of the workpiece that has been manufactured,this topic proposes an algorithm for traversing the polygons to check distance if it is lower than limit distance.And an adaptive layer number enhancement algorithm is proposed to achieve adaptive layer increasing.The experimental results show that the algorithm can accurately calculate the position of the possibility of interference,and realize the adaptive layer increase according to the shape of the model.