Effects of Geometric Parameters of Wavy-Edge Bull-Nose Helical End-Mill on Cutting Force Prediction in End-Milling of Inconel 718 under MQL Cooling Strategy

Abstract

This paper presents the results of the development of a mechanistic cutting force prediction model for wavy-edge, bull-nose, helical endmill (WEBNHE), which was validated and used to investigate the effects of the geometric parameters of the WEBNHE on the predicted cutting force components and the resultant cutting force. The mechanistic cutting force prediction model was validated by conducting end-milling experiments on Inconel 718 and incorporating the effect of the Minimum Quantity Lubrication (MQL) cooling strategy through experimentally identified six cutting force and edge force coefficients. The geometric parameters investigated in this research were: the wavelength, wave magnitude, axial shift of the linear part, and the helix angle of the wavy cutting edges. These parameters were varied one at a time, and the cutting force components for each variation were predicted using the mechanistic cutting force prediction model. The results show that the predicted and measured cutting force components were in good agreement in magnitude and shape. The cutting force components generated from the end-milling under the MQL cooling strategy were lower than under the emulsion cooling strategy. The magnitudes and shapes of the predicted cutting force components and the resultant cutting force of the WEBNHE were unique (asymmetric) in magnitude and shape compared to those of standard, bull-nose, helical endmill (SBNHE) due to the uniqueness of the wavy-cutting edge geometry.

The results also show that the predicted cutting force component in the feed direction Fy is the largest and the most affected by the geometric parameters, followed by Fx. However, Fz is insignificantly affected. It was also observed that the maximum magnitudes and ranges of the cutting force component in the feed direction Fy and the resultant cutting force FR increased with an increase in the wave magnitude and decrease with increase of the wavelength, axial shift, and the helix angle. The wavy cutting edge spends more time in the cutting zone than the standard, helical, cutting edge; this extra time affects the frequency content of the cutting force signals generated by the endmill and improves the end-milling dynamics. Additionally, the distribution of the cutting forces on the wavy cutting edges was not equal due to the asymmetric cutting edge geometry.

Department(s)

Mechanical and Aerospace Engineering

Research Center/Lab(s)

Intelligent Systems Center

Keywords and Phrases

Geometric parameters of wavy-cutting edges; Wavy-edge bull-nose helical endmill; Minimum Quantity Lubrication; Mechanistic cutting force prediction; Inconel 718

International Standard Serial Number (ISSN)

1526-6125; 1878-6642

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Elsevier, All rights reserved.

Publication Date

01 Aug 2016

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