On Wedge Indentation and Its Relationship With Incipient Plastic Deformation in Metal Cutting

1977 ◽  
Vol 99 (3) ◽  
pp. 702-707 ◽  
Author(s):  
K. J. Weinmann
Keyword(s):  
Plastic Deformation ◽  
Plane Strain ◽  
Chip Formation ◽  
Metal Cutting ◽  
Rake Angle ◽  
Wedge Indentation ◽  
Wedge Plate

This paper deals with plane strain indentation of annealed brass by both symmetric and half wedges, and the connection between wedge indentation and incipient chip formation by a positive rake angle tool. Indentation forces and wedge-plate contact lengths were measured, and plastic deformation underneath the indenters was studied by microhardness scanning and discussed. Half-wedge indentations at decreasing distances from the plate corner were shown to result in a transition from wedge indentation to chip formation.

scholarly journals Simulation of plastic deformation and destruction in the process of chip formation

2018 ◽  
Vol 211 ◽  
pp. 17007
Author(s):  
Tanel Tärgla ◽  
Jüri Olt ◽  
Olga Liivapuu
Keyword(s):  
Plastic Deformation ◽  
Formation Process ◽  
Chip Formation ◽  
Rheological Model ◽  
Metal Cutting ◽  
Depth Of Cut ◽  
Key Factors ◽  
Local Zone ◽  
Complex Process ◽  
Relaxing Medium

Metal cutting is a complex process in which several mechanisms are at work simultaneously. The mathematical modelling allows carrying out research into the optimization of machining conditions. This work examines the simulation of chip formation during the process of cutting. The studies demonstrated that the chip formation process, taking into account the plastic deformation and destruction of metal in the local zone, is most appropriately represented by a rheological model in the form of a series connection of elasticductile- plastic relaxing medium of Ishlinskiy (reflecting the process of primary deformation of metal from the cut off layer) and the medium of Voigt with two elastic-dissipative elements (representing the process of deformation and frictions from the convergent shaving). The attained complex rheological model served as the basis for constructing a representative dynamic model for the chip formation process. The key factors that govern the chip formation have been taken into account, such as tool vibration frequency and amplitude, depth of cut, feed rate.

Influence of Rake Angle Tool on Plastic Deformation in Chip Formation when Cutting

2014 ◽  
Vol 682 ◽  
pp. 525-529 ◽  
Author(s):  
A.V. Filippov ◽  
V.V. Gorbatenko
Keyword(s):  
Plastic Deformation ◽  
Shear Deformation ◽  
Contact Area ◽  
Chip Formation ◽  
Maximum Degree ◽  
Experimental Studies ◽  
Rake Angle

The article considers experimental studies of plastic deformation in the area of chip formation when cutting copper M1. According to the results of the research the value of shear deformation was calculated. The change of a rake angle tool γ leads to the change in the process of plastic deformation in the area of chip formation. It was found out that the maximum degree of shear deformation takes place in the contact area of tool tip and deformable sample.

Chip Formation in High-Speed Cutting of Copper and Aluminum

1963 ◽  
Vol 85 (4) ◽  
pp. 365-372 ◽  
Author(s):  
K. J. Trigger ◽  
B. F. von Turkovich
Keyword(s):  
Plastic Deformation ◽  
Chip Formation ◽  
High Speed ◽  
Metal Cutting ◽  
Initial Temperature ◽  
High Speed Machining ◽  
High Speed Cutting ◽  
Work Material ◽  
On Chip ◽  
Cutting Behavior

This paper presents metal-cutting data for the high-speed machining of copper and aluminum, each at two levels of purity, and over a range of workpiece temperatures from −326 deg F (80 deg K) to 550 deg F (560 deg K). It has been found that cutting behavior is influenced by purity of work material, its initial temperature, and extent of tool-chip contact. The influence of plastic deformation on chip hardness has been found to be intimately associated with the purity of the work material.

On the Plane Stress to Plane Strain Transition Across the Shear Zone in Metal Cutting

1988 ◽  
Vol 110 (4) ◽  
pp. 322-325 ◽  
Author(s):  
B. E. Klamecki ◽  
S. Kim
Keyword(s):  
Plane Strain ◽  
Shear Zone ◽  
Plane Stress ◽  
Central Region ◽  
Chip Formation ◽  
Metal Cutting ◽  
High Strain ◽  
Surface Characteristics ◽  
Workpiece Material ◽  
Element Analysis

The effects of the stress state transition from plane stress at the workpiece surface to plane strain in the central region of the chip formation zone were studied. A finite element analysis of the incipient chip formation process was performed. The model included heat generation and temperature induced workpiece material property changes. The primary result is that the unique high strain, high strain rate, large free surface characteristics of the metal cutting process can result in qualitatively different deformation behavior across the shear zone. Temperatures are higher in the regions near the surface of the workpiece than in the central region. In extreme cases, this will result in strain hardening behavior in the plain strain regions and thermal softening of the work material near the surface.

scholarly journals THE INFLUENCE OF MATERIAL MICROSTRUCTURE ON THE CHIP FORMING PROCESS

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Pavel Kovač ◽  
Borislav Savković ◽  
Lepa Siđanin ◽  
Ondrej Lukač ◽  
Ildiko Mankova
Keyword(s):  
Plastic Deformation ◽  
Chemical Composition ◽  
Chip Formation ◽  
Metal Cutting ◽  
Crack Formation ◽  
Forming Process ◽  
Material Microstructure ◽  
Workpiece Surface ◽  
Deformation And Fracture ◽  
Extensive Plastic Deformation

For a number of alloys the process of metal cutting is accompanied by extensive plastic deformation and fracture. In the paper we investigate quick stop samples of the chip formation of materials with different chemical composition and microstructure. The type of chip formation is classified according to the mechanism of crack formation and propagation. During cutting, most samples that are used, quasi-continuous chips with built-up edge (BUE) are obtained. The formation of BUE is undesirable since it is a highly deformed body with a semi stable top which periodically breaks away giving rise to poor workpiece surface quality.

An Explicit Finite Element Model to Study the Influence of Rake Angle on the Discontinuous Chip Formation During Orthogonal Metal Cutting

2009 ◽  
Author(s):  
Pradeep L. Menezes ◽  
Michael R. Lovell ◽  
Jeen-Shang Lin ◽  
C. Fred Higgs
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
Metal Cutting ◽  
Numerical Models ◽  
Rake Angle ◽  
Internal Crack ◽  
Work Piece ◽  
Machining Processes ◽  
Explicit Finite Element ◽  
Orthogonal Metal Cutting

Understanding the tribological aspects of machining processes are essential for increasing the dimensional accuracy and surface integrity of products, as well as gaining a better control of tool wear, chip handling and power consumption. The objective of this investigation is to develop numerical models that accurately predict the chip formation and stress profiles in the work-piece during orthogonal metal cutting using the explicit finite-element method (FEM). In our simulations, a damage material model was utilized to capture the work-piece chip separation behavior and the simultaneous breakage of the chip into multiple fragments. In the simulation, the rigid steel cutter of different rake angles was moved at different velocities against a stationary aluminum work-piece at constant friction for a cutting depth of 1 mm. Overall, the results indicate that the explicit FEM is a powerful tool for simulating metal cutting and discontinuous chip formation. The rake angle had a significant effect on the formation of chip during metal cutting. The formation of discontinuous chip along the contact interface was hypothesized to be due to the internal crack initiation and propagation in front of the tool and above the cutting edge, rather than from the free surface.

On the Metal Physical Considerations in the Machining of Metals

1972 ◽  
Vol 94 (4) ◽  
pp. 1215-1224 ◽  
Author(s):  
S. Ramalingam ◽  
J. T. Black
Keyword(s):  
Plastic Deformation ◽  
Strain Hardening ◽  
Chip Formation ◽  
Metal Cutting ◽  
Dynamic Equilibrium ◽  
Experimental Studies ◽  
Second Phase ◽  
Transmission Electron ◽  
Second Phase Particles ◽  
Strain Hardening Behavior

Experimental studies of plastic deformation produced during metal cutting have shown that a dynamic equilibrium is established between strain hardening and recovery during chip formation. Recrystallization studies on interrupted cut specimens show that the chip is formed by shear on a thin plane or surface which segments the chip into a lamella structure. Scanning and transmission electron microscopy studies on the lateral surfaces of prepolished interrupted cut specimens substantiate the evidence obtained from the recrystallization studies. The chip formation process has thus been found to be strongly sensitive to the metal physics and defect strticture of the material undergoing plastic deformation. The important variables involving dislocation interactions during chip formation are the number and orientation of operable slip systems, certain characteristic dislocation parameters such as stacking fault energy, the interaction of dislocations with vacancies and solute atoms or with second phase particles (both coherent and noncoherent types), the short and long range order of the material, and the temperature of the deformation, all of which affect the strain hardening behavior of the material. In addition, those factors which govern the kinetics of dynamic recovery such as outright collision of dislocation segments, cross slip, and climb induced by a supersaturation of point defects produced in the course of deformation must be considered.

Shear Stress in Metal Cutting

1970 ◽  
Vol 92 (1) ◽  
pp. 151-157 ◽  
Author(s):  
B. F. Von Turkovich
Keyword(s):  
Plastic Deformation ◽  
Shear Stress ◽  
Chip Formation ◽  
Main Parameter ◽  
Metal Cutting ◽  
High Strain ◽  
Energy Requirement ◽  
Large Strains ◽  
Dislocation Theory ◽  
Rate Processes

Since the shear stress is the main parameter influencing the energy requirement in machining, the estimation of this stress remains one of the principal problems in the theory of chip formation. An insight in the behavior of the shear stress can be obtained by considering the process of plastic deformation from the viewpoint of dislocation theory. The theory is developed for high strain rate processes and very large strains.

Numerical Simulation of Cutting Force and Temperature Field in High Speed Machining of Titanium Alloys

2010 ◽  
Vol 37-38 ◽  
pp. 731-734 ◽  
Author(s):  
Cong Ming Yan ◽  
You Xi Lin
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
Chip Formation ◽  
High Speed ◽  
Metal Cutting ◽  
Rake Angle ◽  
Maximum Temperature ◽  
High Speed Machining ◽  
Force Fluctuation ◽  
Cutting Force Fluctuation

Improvements in manufacturing technologies require better modeling and simulation of metal cutting processes. A fully thermal-mechanical coupled finite element analysis (FEA) was applied to model and simulate the high speed machining of TiAl6V4. The development of serrated chip formation during high speed machining was simulated. The effects of rake angle on chip morphology, cutting force and the evolution of the maximum temperature at the tool rake were analyzed with the finite element model. The simulation results show that the segmented chip formation results in cutting force fluctuation. Although the segmentation frequency of the chip increases with the increase of the rake angle, the degree of segmentation becomes weaker and the cutting force fluctuation amplitude decreases. The predicted temperature distribution during the cutting process is consistent with the experimental results given in a literature.

Deformation in Orthogonal Cutting

1970 ◽  
Vol 92 (1) ◽  
pp. 93-102 ◽  
Author(s):  
S. Ramalingam
Keyword(s):  
Plastic Deformation ◽  
Chip Formation ◽  
Deformation Process ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Shear Surface ◽  
Grid Deformation ◽  
Plastic Deformation Process ◽  
Surface Active

This paper examines the plastic deformation process involved in chip formation during orthogonal cutting. Results of the grid deformation studies carried out on polymeric workpieces are reported. Chip formation is shown to result from the action of a curved shear surface, and it is shown that the configuration of the deformation volume during orthogonal cutting is fully determined by the orientation and curvature of the shear surface active during the cutting process. Implications of this model in metal cutting are discussed.

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