scholarly journals High-Speed Cutting of Synthetic Trabecular Bone– A Combined Experimental-Computational Investigation

2021 ◽  
Author(s):  
Macdarragh O'Neill ◽  
Ted J Vaughan
Keyword(s):  
Trabecular Bone ◽  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Computational Modelling ◽  
Isotropic Hardening ◽  
Test Machine ◽  
Modelling Framework ◽  
Wide Range

Orthopaedic surgical cutting instruments are required to generate sufficient forces to penetrate bone tissue, while minimizing the risk of thermal and mechanical damage to the surrounding environment. This study presents a combined experimental-computational approach to deter-mine relationships between key cutting parameters and overall cutting performance of a polyu-rethane-based synthetic trabecular bone analogue under orthogonal cutting conditions. An ex-perimental model of orthogonal cutting was developed, whereby an adaptable cutting tool fix-ture driven by a servo-hydraulic uniaxial test machine was used to carry out cutting tests on Sawbone® trabecular bone analogues. A computational model of the orthogonal cutting process was developed using Abaqus/Explicit, whereby an Isotropic Hardening Crushable Foam elas-tic-plastic model was used to capture the complex post-yield behaviour of the synthetic trabecu-lar bone. It was found that lower tool rake-angles resulted in the formation of larger discontin-uous chips and higher cutting forces, while higher rake angles tended to lead to more continu-ous chip formation and lower cutting forces. The computational modelling framework provided excellent predictions of both chip formation and axial cutting forces over the wide range of cut-ting parameters, when compared to experimental observations. This represents the first experi-mentally-validated computational modelling framework for orthogonal cutting of trabecular bone and excellent potential to be applied to more complex three-dimensional cutting processes in the future.

scholarly journals High-Speed Cutting of Synthetic Trabecular Bone—A Combined Experimental–Computational Investigation

2021 ◽  
Vol 2 (3) ◽  
pp. 650-666
Author(s):  
Macdarragh O’Neill ◽  
Ted J. Vaughan
Keyword(s):  
Trabecular Bone ◽  
Chip Formation ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Computational Modelling ◽  
Cutting Parameters ◽  
Isotropic Hardening ◽  
Test Machine ◽  
Modelling Framework ◽  
Wide Range

Orthopaedic surgical cutting instruments are required to generate sufficient forces to penetrate bone tissue while minimising the risk of thermal and mechanical damage to the surrounding environment. This study presents a combined experimental–computational approach to determine relationships between key cutting parameters and overall cutting performance of a polyurethane-based synthetic trabecular bone analogue under orthogonal cutting conditions. An experimental model of orthogonal cutting was developed, whereby an adaptable cutting tool fixture driven by a servo-hydraulic uniaxial test machine was used to carry out cutting tests on Sawbone® trabecular bone analogues. A computational model of the orthogonal cutting process was developed using Abaqus/Explicit, whereby an Isotropic Hardening Crushable Foam elastic-plastic model was used to capture the complex post-yield behaviour of the synthetic trabecular bone. It was found that lower tool rake angles resulted in the formation of larger discontinuous chips and higher cutting forces, while higher rake angles tended to lead to more continuous chip formation and lower cutting forces. The computational modelling framework provided captured features of both chip formation and axial cutting forces over a wide range of cutting parameters when compared with experimental observations. This experimentally based computational modelling framework for orthogonal cutting of trabecular bone analogues has the potential to be applied to more complex three-dimensional cutting processes in the future.

Experimental and FEM Study of Serrated Chip Formation in High Speed Turning Processes

2011 ◽  
Vol 264-265 ◽  
pp. 1021-1026
Author(s):  
U. Umer ◽  
Li Jing Xie ◽  
Syed Jawid Askari ◽  
S.N. Danish ◽  
S.I. Butt
Keyword(s):  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Serrated Chip ◽  
High Speed Turning ◽  
Serrated Chip Formation

The finite element method (FEM) has been used to model high speed turning processes with orthogonal cutting conditions. In most of the situations, continuous chip formation is used to analyze the turning process due to its stability and allowing many conditions to simplify the process. However with the increasing applications of high speed turning, serrated chip formation is becoming a more common phenomenon in metal cutting. Serrated chips usually occur in machining of difficult to cut materials at or above a threshold speed. An updated Lagrangian formulation has been used in this study which works with element deletion technique based on a failure criterion. The Johnson Cook strain-hardening thermal-softening material model is used to model serrated chip formation. In addition high speed turning experiments were conducted on AISI H13 tubes using PCBN to analyze serrated chip phenomenon. The chips were analyzed after surface treatment using scanning electron microscope. It has been found that the length of cuts in the chip increases with the cutting speed and the chip changes from serrated to discontinuous. Different process variables like cutting forces, chip morphology, stress, strain and temperature distributions are predicted at different process parameters using FEM. The results show cyclic variation in the cutting forces at high cutting speeds due to varying chip load.

Cutting Forces and Surface Roughness in High-Speed End Milling of Ti6Al4V

2013 ◽  
Vol 589-590 ◽  
pp. 76-81
Author(s):  
Fu Zeng Wang ◽  
Jun Zhao ◽  
An Hai Li ◽  
Jia Bang Zhao
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Cutting Forces ◽  
High Speed ◽  
End Milling ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Wide Range ◽  
Radial Depth ◽  
Coated Carbide

In this paper, high speed milling experiments on Ti6Al4V were conducted with coated carbide inserts under a wide range of cutting conditions. The effects of cutting speed, feed rate and radial depth of cut on the cutting forces, chip morphologies as well as surface roughness were investigated. The results indicated that the cutting speed 200m/min could be considered as a critical value at which both relatively low cutting forces and good surface quality can be obtained at the same time. When the cutting speed exceeds 200m/min, the cutting forces increase rapidly and the surface quality degrades. There exist obvious correlations between cutting forces and surface roughness.

Research on Adiabatic Shear during Serrated Chip Formation of High Speed Turning of Hardened Steel

2010 ◽  
Vol 139-141 ◽  
pp. 743-747
Author(s):  
Chun Zheng Duan ◽  
Hai Yang Yu ◽  
Min Jie Wang ◽  
Bing Yan ◽  
Yu Jun Cai
Keyword(s):  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Rake Angle ◽  
Adiabatic Shear ◽  
Cutting Condition ◽  
Serrated Chip ◽  
Serrated Chip Formation

The development of chip morphology, critical cutting condition of adiabatic shear during serrated chip formation and cutting forces were observed and measured by high speed turning experiment for 30CrNi3MoV hardened steel. Results show that the cutting speed and rake angle are leading factors to influence chip morphology and cutting forces. With the increase of cutting speed, the continuous band chip transforms into serrated chip at a certain critical value. As the rake angle is changed from positive to negative, the critical cutting speed of adiabatic shear significantly decreases, the cutting forces abruptly reduces when the serrated chip forms. The results from predicting critical cutting speed using the critical cutting condition criterion of adiabatic shear in metal cutting process show that the leading reason of serrated chip formation is that the adiabatic shear fracture repeatedly occurs in the primary shear zone.

FEA Simulation of the Influence of Cutting Parameters on Serrated Chip Formation in Machining Titanium Alloy Ti-6Al-4V

2012 ◽  
Vol 500 ◽  
pp. 152-156
Author(s):  
Zeng Hui Jiang ◽  
Ji Lu Feng ◽  
Xiao Ye Deng
Keyword(s):  
Titanium Alloy ◽  
Chip Formation ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Element Model ◽  
Serrated Chip ◽  
Wide Range ◽  
Serrated Chip Formation ◽  
Fea Simulation

A finite element model of a two dimensional orthogonal cutting process is developed. The simulation uses standard finite software is able to solve complex thermo-mechanical problems. A thermo-visco-plastic model for the machined material and a rigid cutting tool were assumed. One of the main characteristic of titanium alloy is serrated shape for a wide range of cutting conditions. In order to understand the influence of cutting parameters on the chip formation when machining titanium alloy Ti-6Al-4V. The influence of the cutting speed,the cutting depth and the feed on the chip shape giving rise to segmented chips by strain localisation is respectively discussed.

FEM Analysis of Residual Stress Distribution and Cutting Forces in Orthogonal Cutting with Different Initial Stresses

2014 ◽  
Vol 800-801 ◽  
pp. 380-384 ◽  
Author(s):  
Yuan Ma ◽  
Ding Wen Yu ◽  
Ping Fa Feng
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Compressive Stress ◽  
Cutting Forces ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Cutting Parameters ◽  
Initial Stresses

Machining induced residual stress is influenced by many factors. Extensive studies on the influence of cutting parameters, tool parameters, as well as basic properties of materials have been carried out during the past decades, while another important factor, initial stress distribution in workpiece, was often ignored. In this paper a relatively complete FEM simulation on the formation mechanism of machining induced residual stress in high speed machining is carried out, illustrating the three stress zones affected by mechanical and thermal loads, and their influence on ultimate residual stress. And the influence of initial compressive stress on stress formation and cutting forces is analyzed. Initial compressive stress weakens the tensile effect caused by the shear deformation, and the residual stress tend to be more compressive with larger initial compressive stress. Cutting force becomes larger with the increase of initial compressive stress. And the results in this FEM study can be used to explain some unaccounted experimental phenomena in former researches.

An Investigation into the Dependency of Cutting Forces on the Volume Fraction and Fibre Orientation during Machining Composite Materials

2017 ◽  
Vol 882 ◽  
pp. 61-65
Author(s):  
Fadi Kahwash ◽  
Islam Shyha ◽  
Alireza Maheri
Keyword(s):  
Cutting Forces ◽  
High Speed ◽  
Volume Fraction ◽  
Fibre Orientation ◽  
Orthogonal Cutting ◽  
Fibre Volume Fraction ◽  
High Speed Steel ◽  
Fibre Volume ◽  
Force Model ◽  
High Dependency

This paper presents an empirical force model quantifying the effect of fibre volume fraction and fibre orientation on the cutting forces during orthogonal cutting of unidirectional composites. Glass fibre plates and high speed steel cutting tools are used to perform orthogonal cutting on shaping machine whereas cutting forces are measured using platform force dynamometer. The analysis of forces shows almost linear dependency of cutting forces on the fibre content for both cutting and thrust forces. High dependency of cutting forces is also observed on fibre orientation with high percentage contribution ratio (up to 95.31%). Lowest forces corresponded to 30o and highest to 90o fibre orientation. Multivariate regression technique is used to construct the empirical model.

Identification of Material Constitutive Laws for Machining—Part II: Generation of the Constitutive Data and Validation of the Constitutive Law

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Bin Shi ◽  
Helmi Attia ◽  
Nejah Tounsi
Keyword(s):  
Shear Zone ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Orthogonal Cutting ◽  
Material Behavior ◽  
Constitutive Law ◽  
Primary Zone ◽  
Wide Range ◽  
Static Conditions ◽  
Secondary Shear Zone

This paper presents an integral methodology to obtain a wide range of constitutive data required for the identification of the constitutive equation used in simulating cutting processes. This methodology is based on combining the distributed primary zone deformation (DPZD) model developed in Part I (Shi et al., 2010, ASME J. Manuf. Sci. Eng., 132, p. 051008.) of this study with quasi-static indentation (QSI) tests, orthogonal cutting tests at room temperature (RT) and high temperature. The QSI tests are used to capture the material properties in the quasi-static conditions, which solve the unstable solutions for the coefficients of the constitutive law. The RT cutting tests are designed to fulfill the assumptions embedded in the developed DPZD model in order to provide the distributed constitutive data encountered in the primary shear zone. To capture the material behavior in the secondary shear zone, the orthogonal cutting tests with a laser preheating system are designed to raise the temperature in the primary zone to the level encountered in the secondary zone. As an application of the generated constitutive data, the Johnson–Cook model is identified for Inconel 718. This constitutive law is further validated using high speed split Hopkinson pressure bar tests and orthogonal cutting tests combined with finite element simulations. In comparison with the previous approaches reported in the open literature, the developed DPZD model and methodology significantly improve the accuracy of the simulation results.

Investigations on the Nature of Surface Finish and Its Variation With Cutting Speed

1964 ◽  
Vol 86 (2) ◽  
pp. 134-140 ◽  
Author(s):  
K. L. Chandiramani ◽  
N. H. Cook
Keyword(s):  
Surface Finish ◽  
Chip Formation ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Relative Importance ◽  
Cutting Mechanism ◽  
Low Speed

An attempt has been made to investigate the nature and cause of the variation of surface finish with cutting speed during orthogonal cutting operations. It is found that the variation of cutting speed alone is sufficient to give rise to the three different mechanisms of chip formation, conventionally known as discontinuous, continuous without “bue” (built-up-edge) and continuous with bue. The transition from low-speed, nonbue cutting to high-speed, bue cutting is found to greatly influence the surface finish and in fact the entire cutting mechanism. Photomicrographs of the cutting zones, the chips, and the profiles of the finished surfaces have been taken to observe these changes closely. Tests have also been carried out to determine the relative importance of cutting speed and cutting temperature in affecting the surface finish of the workpiece being machined.

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