A Predictive Method for Cumulative Tool Wear in Variable Cutting Speed Turning Operations

This study investigates cumulative tool wear in turning operations, focusing on the machining of AISI 1045 steel. Tool wear is a critical factor in determining the overall efficiency of machining processes. While current standards such as ISO 3685 provide guidelines for constant cutting speed, real industrial applications frequently involve variable cutting speeds, which leads to cumulative tool wear. The aim of this research is to develop a robust method for predicting tool-life when using variable cutting speeds. The proposed method is based on conducting tool-life tests at constant speeds, followed by the plotting of empirical tool-wear curves for each speed. These curves are then combined to build a cumulative tool-wear model that accounts for variations in cutting speed throughout a machining cycle. Experimental tests were conducted using coated carbide tools, and the wear was monitored using flank wear width (VB) as the primary criterion. Results show that nonlinear effects, which are often presumed to complicate tool-life prediction under variable speeds, have a marginal impact on tool wear progression. The proposed method effectively predicts the useful tool-life by combining the wear curves from different cutting speeds, making it suitable for practical industrial applications. Validation through variable cutting speed tests confirmed the accuracy of this method, as the predicted tool-life closely matched the experimental results. This approach provides a reliable alternative for estimating tool-life in complex machining operations with varying cutting conditions.