Warpage/Distortion in Machining 7050-T7451 Alloy Components

Investigation of the feasibility of development of a mathematical model that will have the capability to provide machine operators with specific guidelines for efficient machining, while minimizing any distortion and warpage, is the main objective of the proposed Phase I effort. The most challenging aspect of this project is the development of a validated mathematical model for the effects of machining-induced residual stresses (MRS). Previous investigation indicated that the influence of machining-induced residual stresses increases with decreasing part thickness. Furthermore, machining-induced residual stresses depend on tool sharpness, corner radii, machining pattern, feed rate and other controllable parameters. It will be necessary to develop a mathematical model capable of predicting the effects of end mill process parameters, specific to alloy and part geometry. MRS caused by metal cutting and grinding operations are confined to a very thin surface layer. Convincing correlation was found between tool diameter, tool sharpness, corner radii and machining pattern. These correlations are likely to be size-dependent and there is statistical variability, yet to be quantified. It is expected that the residual stress pattern is periodic.