Methodology for automatic fixture design in a computer-integrated environment
Abstract
The objective of this research is to develop a general methodology for automatic fixture design (AFD) concerning the automation and integration issues in a computer environment. The research effort covers several major topics. These topics are studied as general methodology which can also be extended to solve other manufacturing problems. First, a set of proper workpiece orientations is determined. The orientation information is important for the planning of workholding, machining sequence, and production scheduling. To select the required workpiece orientations for all manufacturing activities, information about the workpiece geometry, the available manufacturing tools, and the job specification in general is considered in the analysis procedure. Second, a methodology for automatic workholding configuration is developed to generate the fixturing points for each workpiece orientation. The Projective Spatial Occupancy Enumeration (PSOE) approach is applied to develop the configuration algorithms which can automatically generate the fixturing points for any workpiece with general (prismatic or non-prismatic) shape. Third, an automatic workholding verification model is provided to verify the fixturing results for any workpiece. This model is developed under the domain of the general workholding; therefore, it can be used to verify other holding applications, such as the robot-hand (grasping) or mechanical manipulators. The model is developed by using non-linear programming to incorporate the fixturing conditions and constraints. These conditions include the force equilibrium, the frictional affects, the workpiece geometry constraints, and the fixturing force limits. Fixture design is one of numerous tasks in a complete manufacturing planning procedure. The AFD results are influenced by planning decisions other than fixturing, and are also used as inputs for these planning activities. Therefore, information integration between the AFD system and the other computer assisted design and planning modules are studied as the fourth research topic. In order to increase the degree of global automation and eliminate the human interaction for information transformation, an integration system shell, called MetaDesigner, is developed. The results of this research provide a global methodology to solve the automation and integration issues in fixture design.
Degree
Ph.D.
Advisors
Liu, Purdue University.
Subject Area
Industrial engineering|Mechanical engineering|Systems design
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