Contact condition modelling for machining fixture setup processes

Manufacturing automation often requires high precision and highly accurate equipment to achieve satisfactory performance. In many cases, precision and accuracy depend highly on the surface contact conditions between machine components. Described in this paper is the modelling of the response frequency of a modular fixturing system with multiple components in contact, and it has demonstrated that it is possible to monitor the contact conditions based on a fixture system's dynamic response frequencies. The virtual spring element based on the Hertz theory is used to recapitulate the fixture contact conditions in the finite element modelling. Possible contributing factors to contact conditions, such as material properties, surface finish, hardness and the contact area between the workpiece and fixture device, are investigated in the estimation of the virtual spring constant. Experimental analysis is also conducted to verify the analytical model. The application of this model can be used for control, monitoring, and design of general clamping devices in many manufacturing processes; (C) 1999 Elsevier Science Ltd. All rights reserved.