Experimental Study on the Minimum Undeformed Chip Thickness Based on Effective Rake Angle in Micro Milling.

Xian Wu,Yuan Li,Jianyun Shen,Li Liu,Mingyang Du,Feng Jiang,Yiyang Lin

doi:10.3390/mi11100924

Xian Wu, Yuan Li + Show 5 more

Open Access

https://doi.org/10.3390/mi11100924

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Abstract

Micro milling is widely used to manufacture micro parts due to its obvious advantages. The minimum undeformed chip thickness, the effective rake angle, and size effect are the typical characteristics and closely related to each other in micro milling. In this paper, the averaging method is proposed to quantitatively estimate the effective rake angle in the cutting process. The minimum undeformed chip thickness is explained based on the effective rake angle and determined to be 0.17 rn (tool cutting edge radius). Then, micro milling experiment was conducted to study the effect of the minimum undeformed chip thickness. It is found that the minimum undeformed chip thickness results in the unstable cutting process, the uneven peaks on cutting force signal, and the dense characteristic frequency distribution on frequency domain signal. The dominant ploughing effect induces the great specific cutting energy and the deteriorated surface roughness due to the minimum undeformed chip thickness.

Highlights

In recent years, the requirements for miniaturization of part and device have become increasing with the rapid development of many fields, such as communications, electronics, biomedicine, etc
The machining parameters are downscaled to several microns level, and the undeformed chip thickness is comparable to the cutting edge radius of micro end mills
Shi et al [14] reported that the minimum undeformed chip thickness is 1.4 μm for micro milling of Inconel 718 based on the acoustic emission signal

Summary

Introduction

The requirements for miniaturization of part and device have become increasing with the rapid development of many fields, such as communications, electronics, biomedicine, etc. The tool cutting edge radius cannot be ignored and becomes an important factor [4] The induced problems, such as the size effect, the minimum undeformed chip thickness, and effective rake angle, have significant effect on the cutting process and machining quality [5,6]. The size effect mainly is caused by the tool cutting edge radius, the change of material properties, and micro friction at the downscaling undeformed chip thickness. Shi et al [14] reported that the minimum undeformed chip thickness is 1.4 μm (tool cutting edge radius of 6 μm) for micro milling of Inconel 718 based on the acoustic emission signal. The Determination of Minimum Undeformed Chip Thickness Based on Effective Rake Angle

The Calculation Model of Effective Rake Angle

The Determination of Minimum Undeformed Chip Thickness

Experimental Procedure

The Effect of the Minimum Undeformed Chip Thickness on Cutting Process

The Effect of the Minimum Undeformed Chip Thickness on Cutting Force Signal

Conclusions