Automated Verification of Clamping Stability in Computer-Aided Fixture Design

Abstract This paper presents a method for automated verification of clamping stability in computer-aided modular fixture designs. When a modular fixture design is conducted by using a CAD system, equilibrium between clamping forces and locating responses needs to be evaluated for a reliable locating. If the positions and directions of locating and clamping components are not appropriately placed, the clamping action may not secure the locating but destroy it. In this paper, two technical problems related to clamping stability verification are studied: automated extraction of positions/directions of clamping forces and locating responses, and evaluation of clamping equilibrium of the fixture design. The automated extraction of the locating/clamping positions/directions is implemented by adding special attributes into a fixture component CAD database based on an analysis of locating and clamping methods using modular fixture components. To verify the clamping stability of a fixture design, the clamping forces are assumed as active and known input forces, and the locating responses are passive and variables to be solved. In the solution, all locating responses should be non-negative for a stable clamping, and the friction should be in a feasible range for a stable clamping.