Optimization of Fixture Layout and Clamping Force in a Concurrent Environment to Improve the Part Quality in Milling Operations

Abstract

Fixture layout design (FLD) determines the specific position of locators and clamps to position and support the workpiece with respect to a machine tool. The FLD approaches that use Finite Element Analysis (FEA) are widely used in previous works, and it becomes computationally expensive and specific to a particular problem. Further, the FLD and clamping force optimization were often performed separately, ignoring their interdependence. In the present work, to maximize the dimensional and form quality of the part, the reaction forces of the locators are made uniformly distributed by suitably varying the fixture layout and clamping force. The parametric rigid body model is used to depict the behaviour of the workpiece-fixture system, and it is incorporated with the genetic algorithm to optimize the design variables. A prismatic workpiece with slot milling operation is considered to validate the proposed methodology. Stability criterion and tool-fixture interference are considered constraints. Subsequently, FEA is used to verify the integrity of the proposed approach. The results infer that the uniformity in distribution of maximum elastic deformation of the workpiece is achieved due to the uniform distribution of reaction forces. Further, the effects of cutting forces on fixture layout and clamping forces are studied.