Material characterization for finite element simulation of orthogonal cutting and drilling.

Abstract

Machining is used extensively in many industries and is one of the most common manufacturing processes. Research in the field of machining and drilling modeling has spanned the past few decades. Open research issues include material and frictional properties for use in finite element models, machining temperature measurement, and drill temperature model. A coupled mechanical-thermal finite element model of orthogonal cutting process is developed to predict machining forces and temperature. Two critical inputs to the finite element model are the material flow stress property and the tool-chip interface frictional property. Iterative schemes based on simple analytical equations were first developed to determine the flow stress and frictional parameters for use in finite element simulation. A two-stage finite element simulation of the machining process is carried out next using those material and frictional parameters. The model predicts machining forces, temperature distribution of the tool, as well as stress, strain, and temperature distributions of the chip for various cutting conditions. Temperature distribution of the tool is measured by an infrared thermal imaging system. The predicted and experimental machining forces and temperatures are shown to be in good agreement. A drill temperature model, which includes both the chisel edge and main cutting edges of the drill, is presented. The model uses a new method of calculating the heat flux load, which significantly reduces errors in the chisel edge region. Contrary to most previous drill temperature models, which predict that the maximum temperature always occurs at the outer cutting corner of the drill, the current model predicts that the maximum temperature can sometimes occur on the chisel edge of the drill. The predicted temperature profile by the current drill temperature model agrees with the measured temperature profile.