An Experimental Investigation on Micro End Milling with High-Speed Up Cut Milling for Hardened Die Steel.

Haruki Kino,Hitomi Kojima,Keiji Ogawa,Heisaburo Nakagawa,Takumi Imada

doi:10.3390/ma13214745

Abstract

The importance of micromachining using small diameter end mills and the dies used for them has been increasing in the machining of small parts. However, the reality is that there are various requirements to improve the machining surface, machining accuracy, machining efficiency, and tool life. Therefore, this paper discusses the possibility of satisfying these requirements by high-speed up cut milling in side cutting. The goal of this study was to solve the aforementioned problems, by conducting a detailed analysis of the machining phenomena in order to understand their mechanisms. In particular, the effects of high-speed cutting using a high-speed air-turbine spindle with highly stiff rolling bearings were analyzed. Moreover, cutting experiments were conducted by measuring the cutting force and flank wear of the tool, to reveal the differences in the cutting phenomena relative to the cutting direction in high-speed micro end milling. Description of the machined surface and the measurement of its profile were also included in the discussions. On the basis of the results, high-speed up cut milling is a better choice than down cut milling; furthermore, a high-feed rate further increases machining efficiency and improves tool life.

Highlights

In recent years, there has been a continuous drive toward miniaturization and high-precision platforms for medical; optical; and electronic devices, parts, and equipment
In order to investigate the effect of high-speed up cut milling, we first observed differences in tool wear with cutting length as a basic cutting phenomenon
In our past research [21], it was found that the cutting phenomenon becomes unstable and the tool life was reached when the average flank wear width reaches only 12 μm in the case of the same 0.5 mm diameter end mill as the present one

Summary

Introduction

There has been a continuous drive toward miniaturization and high-precision platforms for medical; optical; and electronic devices, parts, and equipment. To meet the demand for shortening the delivery time of dies required for the manufacture of these products and parts, high accuracy and high-efficiency machining is imperative. It is desirable to establish an effective machining method such as an advanced micro end milling technology. The most commonly used method in end milling on high-speed machining centers is down cut milling. In the past, up cut milling was sometimes used because of the backlash of the machine and the characteristics of the cutting tool material. It is only in recent years that down cut milling has been recognized as the normal machining method, owing to its longer tool life and better machining accuracy. In the case of precision machining of a vertical wall profile, it is often more practical

Objectives

Methods

Results

Conclusion