A concurrent fixture design and assembly methodology for computer-integrated manufacturing systems

Shahid Saleem Ahmed, Purdue University

Abstract

The objective of this research is the integration of automated fixture design and automated fixture assembly activities. This is an important requirement due to the continually growing demand for efficient and agile manufacturing technologies. The concurrent fixturing approach developed in this research provides a framework for the integration and capability enhancement in these two areas. A one to one functional mapping of workholding capability to the fixture design domain has been devised. This is utilized in the hierarchical development of innovative fixturing hardware solutions which meet automation, integration and concurrency criteria. Issues of cost, complexity and rigidity are addressed. A device for programmable assembly assistance to the operator is proposed. At the CAD based automated fixture design stage, the same functional mapping is utilized to impose workholding constraints on a 3D solid model representation of the workpiece. Design criteria used includes modeling of cutter path interference and surface conditions of the workpiece. Accessibility, surface incidence and topological constraints of the workpiece are processed. Optimal placement of the workpiece over the pallet is determined by shift and scan evaluation of all constraints based on which the fixture layout is automatically generated. The design approach has been implemented using the TWIN solid modeler on a Silicon Graphics workstation. Very fast processing times are demonstrated for 3D workpieces of industrial complexity, using fixturability algorithms developed in this research. The output generated can be directly used as instructions for automated fixture assembly. ^

Degree

Ph.D.

Advisors

Major Professors: Moshe M. Barash, Purdue University, C. Richard Liu, Purdue University.

Subject Area

Engineering, Industrial|Engineering, Mechanical

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