Analysis and Evaluation of Process Planning for Prismatic Machined Parts with Multiple sets of Features

• Main Authors: Lin, Chwan-Cherng, 林傳城
• Other Authors: Yuan-Jye Tseng
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/39306508869730069071

碩士 === 元智工學院 === 工業工程學系 === 84 === In this thesis ,we develop a method to analyze and evaluate the multiple sets of features in the prismatic machined parts. In feature-based design, alternative sets of features can exist to represent the same part model. The main goal of this research is to analyze and evaluate these multiple sets of features in order to find a better set or the best set suitable for manufacturing process planning. In this research ,firstly, a volume decomposition method is used to build basic machined components from feature volumes. Then, a systematic method is developed to reconstruct the basic machined components to generate multiple sets of features. These multiple sets of features are then analyzed and evaluated from process planing point of view. There are two stages in this research. In the first stage, the multiple sets of features are generated by connecting the BMC with the same level and then connecting the blocks along three possible directions to build 3D features and generate the multiple sets of features. In the second stage ,the multiple sets of features are analyzed and evaluated from process planning of view by considering two factors, tool paths and fixturing design. Machining a part by using different feature sets requires different sets of tool paths that may differ in length of paths. A method for cutting tool path and non-cutting tool path planning and calculation of these prismatic features are developed. The multiple sets of features are then analyzed and evaluated by calculating the length of different tool paths. The total cutting time of each of these multiple sets of features is also evaluated. A method for feature-based fixturing design by using 4-2-1 location principle is developed to evaluated the fixturing requirement for machining the multiple sets of features . Since machining a part by using different set of features may produce different intermediate shapes during machining, there may require different fixturing methods for different intermediate shapes in machining different sets of features. The multiple sets of features are then analyzed and evaluated based on the times of the fixturing changeovers resulted from the different shape of the intermediate workpieces. Finally, all the above factors are combined to conclude a better set or a best set of features. The contribution of this research is to find a better set of features from the multiple sets of features. Such that a better way to integrate CAD and CAM can be found.Keywords:CAD, CAM, tool path, fixture design.