Experiment Modeling of Response Parameters and CBN Tool Wear in Continuous and Interrupted Hard Turning of AISI D6 Steel

Manoj Nayak,Rakesh Sehgal

doi:10.17485/ijst/2019/v12i19/143902

Abstract

Objectives: This study aims at providing solution to shop floor engineers on parametric selection of hard machining during reconditioning of damaged tools and dies after a certain period of life. Methods/Statistical Analysis: Experiments were conducted for hard turning of continuous and interrupted surfaces using Cubic Boron Nitride (CBN) tools on a highly automated all geared lathe using force dynamometer and surface roughness tester. In this experiment the influence of cutting speed, feed and CBN tool material properties on main cutting force, thrust force, surface roughness and cutting temperature has been experimentally investigated in continuous and interrupted turning. A total of 54 experiments were conducted for both continuous and interrupted surfaces and standard statistical methodology is applied. Findings: Statistical checks (ANOVA analysis, R2 statistics, p-values) indicated that the models were adequate. Thrust force is higher and surface finish is better in case of interrupted cutting as compared to continuous cutting. The results also showed that the feed strongly influences the main cutting force and surface roughness; cutting speed strongly influences the cutting temperatures; feed strongly influence the surface roughness in both continuous and interrupted machining. The predicted responses were close to the experimental values and the proposed experimental models can be used to improve the hard turning processes. Chipping of the cutting edge was predominantly found in continuous turning but did not occur in interrupted turning at 102 m/min. The tools failed mechanically at very low speed in both the cases. Abrasion, adhesion, diffusion and chemical wear are the different wear mechanisms observed during hard turning of AISI D6 steel. Application/Improvements: This research establishes the capability of hard turning as an alternative to grinding process so as to avoid use of cutting fluid due environmental hazards. By selecting proper process parameters of speed, feed and depth of cut, selection of tool grade, dry hard turning can be accomplished economically. Keywords: Continuous, Cutting Force, Hard Turning, Interrupted, Surface Roughness

Highlights

Precision finish hard turning has the potential to replace the grinding operation in some applications
The thrust force is the dominant force as compared to the main cutting force
The thrust forces in interrupted cutting were of higher magnitude than that in continuous cutting

Summary

Introduction

Precision finish hard turning has the potential to replace the grinding operation in some applications. In some cases components are hard turned to remove the distortions due to hardening and tempering, to achieve a better. Experiment Modeling of Response Parameters and CBN Tool Wear in Continuous and Interrupted Hard Turning of AISI D6 Steel surface finish. With the advent of CBN tools technology, these processes, were successfully carried out in industries, thereby resulting in less grinding operations, low cutting fluid consumption, lead time reduction in manufacturing, flexibility in the process planning, good surface finish and higher material removal rates according to[1]. Research on assessing machinability of work material, monitoring tool wear and tool lives, evaluating surface integrity, experimental modeling and analysis are done to give a new direction to metal cutting research

Objectives

Methods

Results

Conclusion