A fast interference checking algorithm for automated fixture design verification

Fixtures are tooling devices used to locate, support and hold workpieces during a manufacturing process. The major purpose of a computer-aided fixture design (CAFD) system is to provide a fixture design based on fixturing principles and,workpiece information. interference checking between the machining tool and fixture units, as well as between fixture units, is one of the important functions of automated fixture design. This paper presents a fast interference checking algorithm for automated modular fixture design validation. It is based on the study of the geometric characteristics of modular 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 line segment in 5-axis operations, as the fixture component model is expanded according to the tool radius. The method is different from the popular collision detection procedure using swept volume and is more efficient for fixturing verification. Application of this method will greatly reduce the computation complexity for fixturing interference checking. The method is implemented with a CAFD system. An example is given at the end of the paper.