The Determination of Workpiece Fixturing Scheme Based on Gray Relation Analysis Method

Abstract

The design of machining fixtures is a highly complex process that heavily relies on designer experience and his/her implicit knowledge to achieve a good design. The determination of fixturing scheme is an optimizing problem with multi-objective and multiconstraint. In order to evaluate the fixturing scheme objectively, a fixturing design scheme selection objective system is developed according to the feature of multi-level and multi-index of fixturing design scheme. With location accuracy, contact force, workpiece deformation and successive fixturing as the objective functions, the optimization selection of mathematical model of fixturing design scheme is established, then it is solved by gray relation analysis and analytic hierarchy process. The method provides a qualitative and quantitative combining analysis for a fixturing design scheme: (a) verifying whether a particular fixturing scheme is valid with respect to locating stability, deterministic workpiece location, clamping stability and total restraint and (b) determining the optimal fitness value based on integrate performances. An example is presented to demonstrate the effectiveness and the capabilities of the methodology. The study shows the gray relation analysis and the analytic hierarchy process can improve selecting quality for determination of fixturing design scheme.