The influence of the process parameters on the surface integrity during peripheral milling of Ti-6Al-4V

Abstract

The titanium alloy Ti-6Al-4V represents a significant metal portion of state-of-the-art aircraft structural and engine components. When critical structural components in the aerospace industry are manufactured with the objective to reach high reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of machined surfaces. The residual stresses and the surface alteration induced by machining titanium alloys are critical due to safety and sustainability issues. In this paper, a series of end milling experiments was conducted to comprehensively characterize the surface integrity at various milling conditions. The experimental results have shown that the surface roughness value increases with the feed and the cutting velocity. However, the residual stress state in the surface layer zone is influenced by the variation of the process control variables. Here, compressive residual stresses occur both in cutting and in feed direction. In addition, a new type of sensory tool holder is presented, which should enable the indirect measurement of residual stresses during the milling process.

Parameter Identification for Thermo-Mechanical Constitutive Modeling to Describe Process-Induced Residual Stresses and Phase Transformations in Low-Carbon Steels

“…The experimental parameters for the stress measurements with XRD are shown in Table 2. The residual stresses were measured in between the non-uniform ribs of the rebars using the sin 2 ψ method [36,37]. The penetration depth of the Cr K α radiation was calculated to be 11 µm in this alloy using the software xraylib [38].…”

Determination of the Cutting-Edge Microgeometry Based on Process Forces during Peripheral Milling of Ti-6Al-4V Using Machine Learning

“…During the peripheral milling experiments, a tool holder with integrated sensors was used to measure the forces [27]. The occurring forces generated a bending moment in the tool holder, which can be converted into the cutting forces in the Cartesian coordinate system, F x , F y , and F z .…”

“…The stresses were determined using the sin-2ψ method. This method is based on determining the elastic lattice strains, which are converted to stresses by the 3D form of Hooke's law [27,31]. The macro stresses distort the crystal lattice, resulting in an angular shift of the diffraction peak selected to measure the residual stresses.…”

Machine Learning of Surface Layer Property Prediction for Milling Operations

“…Influence of cutting parameters on SLP are mentioned in standard reference works for different machining processes [1,16,17]. Several researchers report relations between cutting speed vc, tool feed fz, cutting width ae and the resulting SLP [3,[18][19][20][21][22]. Microhardness and residual stresses are influenced differently depending on the feed direction [23,24].…”