GOALI/Collaborative Research: Thermomechanical Investigations of High Speed Machining of Aluminum

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

During the machining of metals, plastic deformation and friction lead to the production of heat in the workpiece, which results in complex deformation in the cutting zone. Recently, several numerical models of this highly coupled process have been produced in response to the increased interest in high speed machining. However, while a small number of researchers, in the past and recently, have examined temperature fields during cutting at low or traditional cutting speeds, few if any experimental studies exist that measure temperature fields in the work piece during cutting at high speeds, i.e. 20-100 m/s. It is important to characterize the thermal field in the cutting zone during high speed machining in order to characterize friction and wear characteristics in this area and to understand the heat generated there, which affects chip formation and possibly residual stress formation as well. Ultimately, such investigations should direct further advancement in materials development for high speed machining applications. In this work, infrared detectors are used to experimentally measure the temperature distribution at the surface of a workpiece during high-speed orthogonal cutting, and complex numerical models are developed to predict and understand the active mechanisms of deformation and failure. Finally, from these temperature measurements and models, the heat generated in the primary deformation zone is examined, characterized and related to the residual stress distribution in the workpiece. The main thrust is to better understand, and therefore reduce, the effects of residual stress on distortion of high-speed machined, thin walled components. The approach draws on the experience of experimental, numerical and industrial researchers to attack this difficult, economically relevant problem with a comprehensive experimental, theoretical and developmental approach. Specific benefits of the proposed work are: (1) Detailed understanding the interplay between finished product quality, material behavior and heat generation in high speed machining; (2) New efficient and accurate computational algorithms to model high-speed machining in order to facilitate full understanding of the observed interactions between tool, material and cut quality or residual stress formation; and (3) New directions in aluminum alloy design for high-speed cutting with emphasis on minimizing the effects of machining and alloy processing parameters on the formation of residual stresses in the finished product. Overall, an integrated materials-mechanics/modeling-experimentation approach to the problem will be used throughout the work leading to a multidisciplinary solution to the problem of residual stress distortion of parts machined at high-speed.