Proceedings of the 7 th Cairo University International Conference on Mechanical Design & Production, MDP-7, Cairo– Egypt, February 15- 17, 2000, pp. 251-260 Framework for Computer Aided Fixture Design and Manufacture System Gadalla, M. A. E*., Kridli, G.T.**, Orady, E. A.**, Yoon, D.** *Cairo University, Faculty of Engineering, Cairo, Giza 12316, Egypt. **University of Michigan-Dearborn, Dearborn, MI 48128-USA. e-mails: orady@umich.edu & gadalla@alpha1-eng.cairo.eun.eg ABSTRACT Currently fixtures can be divided into two main categories: flexible (modular) and dedicated fixtures. In the former, the structure of the fixture is built based on a set of modular components that are selected from off-the-shelf components. This type of fixture is commonly used on milling machines, CNC machines, and coordinate measuring machines (CMM). In the latter category, a fixture structure is built using dedicated specially designed components. This type is mostly built to meet certain functional criteria such as the ease of loading and unloading of workpieces, adjustable and programmable fixtures that are suitable for robotic assembly, and/or complex shaped parts. The objective of this work is to provide a design framework for a computer-aided system design and manufacture of machining fixtures. The main characteristics of the system is to provide the capability to identify locating and fixing surfaces on the workpiece to determine the safe and proper holding forces, the capability to relate holding forces to the machining forces to determine the effect of the holding forces on the critical dimensions of the workpiece, and the ability of extending to other manufacturing fixtures. KEYWORDS Computer-Aided Fixture Design (CAFD), CAPP, Flexible Fixture, Dedicated Fixtures 1.0 INTRODUCTION A fixture is a work holding device used in manufacturing and assembly operations to serve in locating, clamping, and supporting the workpiece. Currently, fixture design is based on the knowledge and experience of the tool design and manufacturing engineers. Verification of the workability of the fixture is often carried out by trial and error. Fixture design is a three-step activity: (1) setup planning, (2) fixture planning, and (2) determination of fixture configuration [1]. The setup planning process is designed to determine the number of the setups needed and workpiece orientation in each setup. It can be considered as a subset of the process planning activity hence it can be searched in computer-aided process planning (CAPP) work. Fixture planning was the focus of many research studies in the area of computer-aided fixture design (CAFD) [1, 2]. It mostly focuses on determining the locating and the clamping points. Automatic generation of fixture configuration would reduce the design efforts and secure consistency of products.