A fast interference checking algorithm for automated fixture design verification

Fixtures are tooling devices used to locate, support and hold workpieces du ring a manufacturing process. The major purpose of a computer-aided fixture design (CAFD) system is to provide a fixture design based on fixturing pri nciples and,workpiece information. interference checking between the machin ing tool and fixture units, as well as between fixture units, is one of the important functions of automated fixture design. This paper presents a fas t interference checking algorithm for automated modular fixture design vali dation. It is based on the study of the geometric characteristics of modula r fixture components and the machining tool. The fixture component model is simplified into a 2D contour model with height information. The tool-path model is represented by a moving dot for 3-axis operations, or a moving lin e segment in 5-axis operations, as the fixture component model is expanded according to the tool radius. The method is different from the popular coll ision detection procedure using swept volume and is more efficient for fixt uring verification. Application of this method will greatly reduce the comp utation complexity for fixturing interference checking. The method is imple mented with a CAFD system. An example is given at the end of the paper.