Machinability study of steels in precision orthogonal cutting

Leonardo Roberto Silva,Paulo Faria,João Paulo Davim,Alexandre Mendes Abrão

doi:10.1590/s1516-14392012005000071

Abstract

The miniaturization of components and systems is advancing steadily in many areas of engineering. Consequently, micro-machining is becoming an important manufacture technology due to the increasing demand for miniaturized products in recent years. Precision machining aims the production of advanced components with high dimensional accuracy and acceptable surface integrity. This work presents an experimental study based on Merchant and Lee & Shaffer theories applied to precision radial turning of AISI D2 cold work tool and AISI 1045 medium carbon steels with uncoated carbide tools ISO grade K15. The aim of this study is to evaluate the influence of feed rate on chip compression ratio (Rc), chip deformation (ε), friction angle (ρ), shear angle (Φ), normal stress (σ) and shear stress (•) for both work materials. The results indicated that the shear angle decreased and chip deformation increased as the chip compression ratio was elevated without significant differences between both materials. Additionally, higher cutting and thrust forces and normal and shear stresses were observed for the tool steel. Finally, the Lee & Shaffer model gave shear plane angle values closer to the experimental data.

Highlights

Micro-machining is becoming an important manufacturing technology due to the increasing demand for miniaturized products in recent years
It can be noticed that when machining AISI D2 steel, the cutting and thrust forces present higher values owing to its superior hardness and tensile strength
Correlations between the chip compression ratio and shear plane angle or chip deformation were obtained for both materials

Summary

Introduction

Micro-machining is becoming an important manufacturing technology due to the increasing demand for miniaturized products in recent years. This is mainly driven by the needs for: greater reduction in size and weight; higher energy efficiency and higher portability in commercial and non-commercial applications. The value of many products can be substantially increased as their size and weight are reduced. Micromachining by shearing is capable of producing high dimensional and geometric accuracy, surface finish quality and sub-surface integrity at reasonably low costs. It should be the first choice amongst various manufacturing processes. As the feed rate and depth of cut are reduced, special attention must be paid to the cutting edge preparation, otherwise the chip will not be generated owing to the side flow effect

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Conclusion