Analysis and Modeling of the Micro-Cutting Process of Ti-6Al-4V Titanium Alloy with Single Abrasive Grain

Łukasz Rypina,Błażej Bałasz,Dariusz Lipiński,Tomasz Szatkiewicz,Wojciech Kacalak

doi:10.3390/ma13245835

Abstract

Modeling of material displacements in the microcutting zone is complex due to the number and interdependence of factors affecting the results of the process. An important problem in the modeling process is the selection of the constitutive model and its parameters, which will correctly describe the properties of the material under the conditions of triaxial compression, which is characteristic for the areas of the contact zone of the blade and the processed material in abrasive machining processes. The aim of the work was to develop computer models (with the use of the finite element method) of the microcutting process with a single abrasive grain, which were verified with the results of experimental tests. The paper presents the methodology of modeling the processes of microcutting with abrasive grains, whose geometrical models were created based on optical scanning methods. Observations of the microcutting process were carried out with the use of a high-speed camera and an optical profilometer. This enabled a detailed observation of the chip formation process, as well as the analysis of the surface topography of microcutting traces. The results presented in the paper indicate the convergence of the results of the numerical and experimental simulations with regard to the geometric parameters describing the scratches formed in the microcutting process and the compliance of the chip-forming process. Thus, the correctness of the selection of the constitutive model (Johnson Cook equation) and its parameters was demonstrated, as well as the correctness of the applied methodology for creating a geometric model that allowed for a reflection of the geometrical parameters of the abrasive grains that coincided with the real objects, thanks to which it was possible to reflect in detail the phenomena occurring in the vicinity of the abrasive grain tip.

Highlights

In precise abrasive machining, its result is determined by the phenomena occurring in the vicinity of an abrasive grain
In the processes of cutting with the single abrasive grains ZS1 and ZS2 recorded with a highcamera, three stages can be observed that are typical for the plowing process (P1), in which the speed camera, three stages can be observed that are typical for the plowing process (P1), in which the processed material has a large predominance of plastic deformation, the transition area (P2), where the processed material has a large predominance of plastic deformation, the transition area (P2), where grain starts cutting, and the material separation stage in the form of a chip (P3)
The chip separation process is influenced by the geometric features of the single abrasive grain and the grain orientation in the is influenced by the geometric features of the single abrasive grain and the grain orientation in the cutting direction

Summary

Introduction

Its result is determined by the phenomena occurring in the vicinity of an abrasive grain. The material separation processes are complex due to the structure and properties of abrasive tools [1], varied geometry of abrasive grain vertexes [2], abrasive grains size, high cutting speeds, locally variable specific cutting resistance and physical properties of the processed material. The recognition of all the phenomena occurring in the vicinity of abrasive grain vertexes [3], despite advanced measuring techniques, is difficult and in some cases impossible. In order to explain the mechanisms of material removal, research is carried out on the processes of cutting by a single abrasive grain [3,4] by analyzing three phases: rubbing, ploughing and cutting. During the grain operation in the rubbing phase, the material deforms mainly elastically and only slightly plastically.

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