Experimental Analysis of Cutting Forces in Actuated Face Milling of Micro Patterns

Abstract

This article presents an experimental analysis on cutting forces in fast tool servo-based face milling of micro structures. These structures can be used as a binary information carrier [1]. For a proper process design on a wide range of materials, knowledge of the cutting forces is necessary. The analysis was conducted on the materials Al7075, AISI4042 and TiAl6V4. The investigated parameters are cutting speed, feed, depth of cut, variable depth of cut change and frequency of change. The experiments were conducted according to a full-factorial design using two levels for all parameters and with the tool in full engagement. The used tool system is based on a piezoelectric actuator, enabling tool tip deflections up to 4.5 kHz with an amplitude of 30 μm. A precise linkage to the angular spindle position allows adjusting the deflection over the width of the rotatory tool tip movement. In analogy to the information carrying micro patterns, sinusoidal structures are generated in the engagement range from 45 to 135 degrees angular tool tip position. In order to minimize possible superimposed vibrations of the dynamometer and amplitude gains of high frequency force signals, a filter is used. The filter is based on an inverse function of the force measurement transfer behavior system with mounted specimen. The effects are evaluated on the mean values of the extracted force signals between 45 and 135 degrees engagement range and compared to the effects of machining without variable depth of cut.