scholarly journals Analysis of Forces in Vibro-Impact and Hot Vibro-Impact Turning of Advanced Alloys

2011 ◽  
Vol 70 ◽  
pp. 315-320 ◽  
Author(s):  
Riaz Muhammad ◽  
Agostino Maurotto ◽  
Anish Roy ◽  
Vadim V. Silberschmidt
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
Three Dimensional ◽  
Element Model ◽  
Machining Process ◽  
Strain Rates ◽  
Machining Processes ◽  
Machined Surface ◽  
Cutting Zone

Analysis of the cutting process in machining of advanced alloys, which are typically difficult-to-machine materials, is a challenge that needs to be addressed. In a machining operation, cutting forces causes severe deformations in the proximity of the cutting edge, producing high stresses, strain, strain-rates and temperatures in the workpiece that ultimately affect the quality of the machined surface. In the present work, cutting forces generated in a vibro-impact and hot vibro-impact machining process of Ti-based alloy, using an in-house Ultrasonically Assisted Turning (UAT) setup, are studied. A three-dimensional, thermo-mechanically coupled, finite element model was developed to study the thermal and mechanical processes in the cutting zone for the various machining processes. Several advantages of ultrasonically assisted turning and hot ultrasonically assisted turning are demonstrated when compared to conventional turning.

3D Simulation of Laser Assisted Side Milling of Ti6Al4V Alloy Using Modified Johnson-Cook Material Model

2013 ◽  
Vol 554-557 ◽  
pp. 2054-2061 ◽  
Author(s):  
Hassan Zamani ◽  
Jan Patrick Hermani ◽  
Bernhard Sonderegger ◽  
Christof Sommitsch
Keyword(s):  
Tool Wear ◽  
Laser Beam ◽  
Cutting Forces ◽  
Three Dimensional ◽  
Material Model ◽  
Element Model ◽  
Milling Process ◽  
Machining Processes ◽  
Side Milling ◽  
Three Dimensional Finite Element

During machining of hard materials, one approach to reduce tool wear is using a laser beam to preheat the material in front of the cutting zone. In this study, a new concept of laser-assisted milling with spindle and tool integrated laser beam guiding has been tested. The laser beam is located at the cutting edge and moving synchronously with the cutter. In experiment, a reduction in the resulting process cutting forces and tool wear has been observed in comparison to milling without laser. A three-dimensional finite element model in DEFORM 3D was developed to predict the cutting forces in the milling process with and without an additional laser heat source, based on a Johnson-Cook-type material constitutive model adapted for high strains and strain rates. Both in experiment and simulation, the deformation behavior of a Ti-6Al-4V workpiece has been investigated. The comparison of the resulting cutting forces showed very good agreement. Thus the new model has great potential to further optimize laser assisted machining processes.

Finite Element Simulation of Rotary Ultrasonic Machining for Advanced Ceramics

2004 ◽  
Author(s):  
Zhichao Li ◽  
Liang-Wu Cai ◽  
Z. J. Pei ◽  
Clyde Treadwell
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Cost Effective ◽  
Element Model ◽  
Machining Process ◽  
Bottom Surface ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Advanced Ceramics

Rotary ultrasonic machining (RUM), a hybrid machining process that combines diamond grinding and ultrasonic machining, has been utilized as a cost-effective material removal method for hard-to-machine materials such as advanced ceramics. In this study, the stress and deformation fields in a ceramic workpiece (92% Al2O3) and the formation of edge chipping during RUM process are investigated using finite element method. Based on a simplified model of RUM process, a three-dimensional finite element model is constructed using axisymmetric eight-node quadrilateral element. In the finite element model, the areas of the workpiece bottom surface that are in contact with the fixture are defined as boundaries of zero displacement in normal direction. A static load is applied to the cutting zone, which is the contact area between the tool’s end face and the bottom surface of the machined slot in the workpiece. The value of the load is calculated from experimental measurements using a dynamometer. Using this model, the maximum von Mises stresses are computed. Initiation and location of the crack, which leads to chipping in RUM process, are also analyzed and compared with experimental results observed under a microscope.

scholarly journals Three-Dimensional Synthesis of Manufacturing Tolerances Based on Analysis Using the Ascending Approach

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 203
Author(s):  
Badreddine Ayadi ◽  
Lotfi Ben Said ◽  
Mohamed Boujelbene ◽  
Sid Ali Betrouni
Keyword(s):  
Surface Defects ◽  
Three Dimensional ◽  
Tolerance Analysis ◽  
Machining Process ◽  
Dimensional Synthesis ◽  
Machining Processes ◽  
Machined Surface ◽  
Manufacturing Tolerances ◽  
Machining Fixtures ◽  
Set Up

The present paper develops a new approach for manufacturing tolerances synthesis to allow the distribution of these tolerances over the different phases concerned in machining processes using relationships written in the tolerance analysis phase that have been well developed in our previous works. The novelty of the proposed approach is that the treatment of non-conventional surfaces does not pose a particular problem, since the toleranced surface is discretized. Thus, it is possible to study the feasibility of a single critical requirement as an example. During the present approach, we only look for variables that influence the requirements and the others are noted F (Free). These variables can be perfectly identified on the machine, which can be applied for known and unknown machining fixtures; this can be the base for proposing a normalized ISO specification used in the different machining phases of a mechanical part. The synthesis of machining tolerances takes place in three steps: (1) Analysis of the relationship’s terms, which include the influence of three main defects; the deviation on the machined surface, defects in the machining set-up, and the influence of positioning dispersions; then (2) optimization of machining tolerance through a precise evaluation of these effects; and finally (3) the optimization of the precision of the workpiece fixture, which will give the dimensioning of the machining assembly for the tooling and will allow the machining assembly to be qualified. The approach used proved its efficiency in the end by presenting the optimal machining process drawing that explains the ordered phases needed to process the workpiece object of the case study.

3D Finite Element Analysis of Prestressed Cutting

2012 ◽  
Vol 591-593 ◽  
pp. 766-770 ◽  
Author(s):  
Rui Tao Peng ◽  
Fang Lu ◽  
Xin Zi Tang ◽  
Yuan Qiang Tan
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Bearing Steel ◽  
Arbitrary Lagrangian Eulerian ◽  
Machined Surface ◽  
Element Analysis ◽  
Simulation Techniques ◽  
Ale Formulation

In order to reveal the adjustment principle of prestressed cutting on the residual stress of hardened bearing steel GCr15, a three-dimensional thermal elastic-viscoplastic finite element model was developed using an Arbitrary Lagrangian Eulerian (ALE) formulation. Several key simulation techniques including the material constitutive model, constitutive damage law and contact with friction were discussed, simulation of chip formation during prestressed cutting was successfully conducted. At the prestresses of 0 MPa, 341 MPa and 568 MPa, distributions of residual stress on machined surface were simulated and experimentally verified. The results indicated that residual compressive stress on machined surface were achieved and actively adjusted by utilizing the prestressed cutting method; meanwhile, within the elastic limit of bearing steel material, the higher applied prestress leads to the more prominent compressive residual stress in the surface layer and subsequently the higher fatigue resistance of the part.

Study on the Effect of Tool Geometrical Parameters on Cutting Forces Based on Finite Element Method

2013 ◽  
Vol 663 ◽  
pp. 580-585
Author(s):  
Zhi Tao Tang ◽  
Tao Yu ◽  
Li Qiang Xu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cutting Forces ◽  
Three Dimensional ◽  
Element Model ◽  
Friction Model ◽  
Geometrical Parameters ◽  
Finite Element Software ◽  
Coulomb Friction Model ◽  
Cutting Model

Based on finite element software DEFORM-3D, a three-dimensional oblique cutting model for aerospace aluminum alloy was built. The material’s flow stress behavior was described with Johnson-Cook constitutive equation. The separation of the chips with the workpiece was realized by the combination of adaptive remeshing technique and separation criterion. The material’s failure was defined by adopting Cockcroft & Latham fracture criterion. The tool-chip friction model was the combination of a Coulomb friction model and shear (sticking) friction model. To validate the finite element model, cutting tests were conducted. The effects of tool geometrical parameters such as flank wear, cutting edge inclination and corner radius on cutting forces were analyzed by three-dimensional oblique finite element model.

Analysis of the Machining Process Using a Thermo-Elastic-Viscoplastic Finite Element Model

Manufacturing ◽  
2002 ◽  
Author(s):  
N. Balihodzic ◽  
H. A. Kishawy ◽  
R. J. Rogers
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Machining Process ◽  
Tool Geometry ◽  
304L Stainless Steel ◽  
Stress Distributions ◽  
Temperature Dependent ◽  
Machined Surface ◽  
Orthogonal Machining

A plane-strain thermo-elasto-viscoplastic finite element model has been developed and used to simulate orthogonal machining. Simulations of cutting 304L stainless steel have been carried out using sharp, chamfered, and honed ceramic tools. Employing a combined thermal and mechanical stress analysis with temperature-dependent physical properties, the finite element model is used to investigate the effect of process parameters, tool geometry and edge preparation on the machining process. Stress and strain distributions within the chip and the elastic tool are presented. In addition, trends in the cutting and thrust forces, contact stress distributions and the plastic deformation beneath the machined surface are studied.

Influence of vertical misfit in screw fatigue behavior in dental implants: A three-dimensional finite element approach

2018 ◽  
Vol 232 (11) ◽  
pp. 1117-1128 ◽  
Author(s):  
Mikel Abasolo ◽  
Josu Aguirrebeitia ◽  
Javier Vallejo ◽  
Joseba Albizuri ◽  
Ibai Coria
Keyword(s):  
Finite Element ◽  
Dental Implant ◽  
Fatigue Failure ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Element Model ◽  
Machining Process ◽  
Dimensional Finite Element ◽  
Definition Of ◽  
Three Dimensional Finite Element

Misfit is unavoidable in dental implant-supported prostheses due to machining process or inappropriate assembling, and the definition of an admissible misfit is still a controversial issue. This work aims to understand the behavior of the screws in dental implant-supported prostheses to estimate an admissible vertical misfit value in terms of screw fatigue failure. For that purpose, a finite element model of a dental implant-supported prosthesis was created and analyzed. Vertical misfits were introduced in different positions, the lower and upper screws were tightened to the bolting force values recommended by the manufacturer, and two different occlusal loads were analyzed. In addition, two different prosthesis materials were studied. Screw load variations were reported and a fatigue analysis was performed. As a result, it was observed that the screw tightening sequence closed small vertical misfits (equal to or less than 40 µm), whereas larger misfits (more than 40 µm) remained open. If the vertical misfit is closed by the end of the tightening sequence, it may be considered equivalent to the ideal fit situation in regard to screw fatigue failure. The prosthesis material had no significant influence on the fatigue behavior.

Rapid Finite Element Prediction on Machining Process

2013 ◽  
Author(s):  
Long Meng ◽  
Xueping Zhang ◽  
Anil K. Srivastava
Keyword(s):  
Finite Element ◽  
Programming Model ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Machining Process ◽  
Fe Model ◽  
Machining Processes ◽  
Machined Surface ◽  
Element Analysis ◽  
Python Language

Finite Element Analysis (FEA) is widely used to simulate machining processes. However, in general, it is time consuming, error-prone, and requires repeated efforts to establish a verified successful Finite Element (FE) model. To rapidly investigate the effects of parameters such as tool angle, feed rate, cutting speed, and temperatures generated during the machining process, an efficient approach is proposed in this paper. The technique has been used to achieve rapid FF simulation during turning and milling processes using Python language programming of Abaqus. Sub-model 1 is programmed to simulate the chip formation process in Abaqus/Explicit. Sub-model 2 is programmed to simulate the cooling spring-back process by importing the machined surface into Abaqus/Implicit. The proposed method is capable of simulating the chip morphology, stress, strain and temperature of the machining process with different parameters immediately. The established FE models are automatically solved in batch by programming script. Post-processing is programmed by Abaqus script to easily achieve and evaluate the simulation results. The Programmed FE models are validated in terms of the predicted chip morphology, cutting forces and residual stresses. This method is extraordinarily efficient saving more than 33% simulation time in comparison to existing FEA approach used for machining processes. Moreover, the script is concise, easy to debug, and effectively avoiding interactive mistakes. The rapid programming model provides a novel, efficiency and convenient approach to thoroughly investigate the effects of a large number of parameters on machining processes.

scholarly journals Finishing Titanium Alloy Cutting Zone Analysis Via Multifunction Measuring System

2015 ◽  
Vol 12 (1) ◽  
pp. 31-33 ◽  
Author(s):  
Czán Andrej ◽  
Šajgalík Michal ◽  
Mário Drbúl ◽  
Jozef Holubják ◽  
Jozef Mrázik ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Cutting Forces ◽  
Machining Process ◽  
Measuring System ◽  
Machining Processes ◽  
Simultaneous Observation ◽  
Thermal Spread ◽  
Cutting Zone ◽  
Biomedical Industry

Abstract With the development of automotive, aerospace and biomedical industry, there is higher demand for exotic alloys, often based on titanium or nickel, though they are hard to machine. Therefore, it is essential to thoroughly understand their behavior during machining. Processes in the cutting zone of said materials are due to the complexity and dynamics defined by specific models. These include some deviations, thus it is essential to improve machining observation methodology, so exhibited errors and deviations are minimal or none. Based on the observations, multifunction measuring system has been designed, which allows simultaneous observation of characteristics such as e.g. cutting forces, deformations and thermal spread without uninterrupting machining process.

scholarly journals Cutting Zone Temperature Identification During Machining of Nickel Alloy Inconel 718

2017 ◽  
Vol 14 (2) ◽  
pp. 24-29
Author(s):  
Andrej Czán ◽  
Igor Daniš ◽  
Jozef Holubják ◽  
Lucia Zaušková ◽  
Tatiana Czánová ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Inconel 718 ◽  
Cutting Temperature ◽  
Cutting Edge ◽  
Cutting Process ◽  
Maximum Temperature ◽  
Machining Processes ◽  
Machined Surface ◽  
Cutting Zone

Abstract Quality of machined surface is affected by quality of cutting process. There are many parameters, which influence on the quality of the cutting process. The cutting temperature is one of most important parameters that influence the tool life and the quality of machined surfaces. Its identification and determination is key objective in specialized machining processes such as dry machining of hard-to-machine materials. It is well known that maximum temperature is obtained in the tool rake face at the vicinity of the cutting edge. A moderate level of cutting edge temperature and a low thermal shock reduce the tool wear phenomena, and a low temperature gradient in the machined sublayer reduces the risk of high tensile residual stresses. The thermocouple method was used to measure the temperature directly in the cutting zone. An original thermocouple was specially developed for measuring of temperature in the cutting zone, surface and subsurface layers of machined surface. This paper deals with identification of temperature and temperature gradient during dry peripheral milling of Inconel 718. The measurements were used to identification the temperature gradients and to reconstruct the thermal distribution in cutting zone with various cutting conditions.

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