Modeling and Analysis of the Effect of Fixture-Workpiece Conformability on Static Stability

Abstract

This paper presents a model for analyzing the effect of global and local conformability on fixture-workpiece system static stability. Global conformability is defined as the geometric similarity between a workpiece and the smallest envelope fit over all contacts. Two conformability metrics, C1 and C2, are introduced to quantify only global, and global plus local conformability, respectively. The model considers all stiffness components of the fixture-workpiece system, including workpiece bulk stiffness. The effect of both conformability metrics on fixture-workpiece static stability is analyzed by means of examples. These examples show that static stability can either increase or decrease with conformability depending on the position of the fixturing elements with respect to the line of action of the externally applied loads. The model is experimentally validated using a pin-array type flexible machining fixture.