Predictive Modeling for Distortion in Large, Thin-Walled Machined Components

Machining of large monolithic structures is standard practice in today’s aerospace world. Driven by cost and performance, it is becoming necessary for airframe manufacturers to machine parts better, faster, lighter, and cheaper than ever before. When machining these large monolithic structures, however, distortion becomes a significant problem. The typical solution to this problem is to machine with lower than optimum material removal rates, and perform additional fixture rotations – both of which add unnecessary time and cost to the manufacturing process. A finite element model has been developed specifically to predict and control these distortions. The model takes into consideration the machining-induced residual stresses, as well as the bulk stresses in the material from the manufacturer.