Shear Angle Relationship With Variable Undeformed Chip Thickness

1974 ◽  
Vol 96 (4) ◽  
pp. 1272-1276 ◽  
Author(s):  
G. S. Kainth ◽  
R. C. Gupta
Keyword(s):  
Metal Cutting ◽  
Chip Thickness ◽  
Present Theory ◽  
Rake Angle ◽  
Shear Angle ◽  
Surface Slope ◽  
Undeformed Chip Thickness ◽  
Orthogonal Metal Cutting ◽  
Effect Of Surface ◽  
Good Agreement

Effect of surface slope of the workpiece on shear angle has been considered by applying Hill’s [1] deformation criteria to the triangular shear zone in orthogonal metal-cutting process with variable undeformed chip thickness. It is shown that the variation of the shear angle with the surface slope δ can be written in the form φ = φ0 + Cδ where “C” is not a constant but depends upon steady state shear angle φ0, surface slope δ, and rake angle α. It is also shown that the present theory is in good agreement with the experimental results of Boothroyd [2].

Effect of Surface Slope on Shear Angle in Metal Cutting

1970 ◽  
Vol 92 (1) ◽  
pp. 115-118 ◽  
Author(s):  
G. Boothroyd
Keyword(s):  
Metal Cutting ◽  
Chip Thickness ◽  
Shear Angle ◽  
Rate Of Change ◽  
Cutting Condition ◽  
Surface Slope ◽  
Undeformed Chip Thickness ◽  
Work Surface ◽  
Machine Tool Chatter ◽  
Effect Of Surface

The effect of the work surface slope, or the rate of change of undeformed chip thickness, on the shear angle in metal cutting is studied experimentally. It is shown that the results of previous analyses only apply to one specific cutting condition and cannot generally be used in studies of machine tool chatter.

Machining Forces: Some Effects of Removing a Wavy Surface

1966 ◽  
Vol 8 (2) ◽  
pp. 129-140 ◽  
Author(s):  
P. W. Wallace ◽  
C. Andrew
Keyword(s):  
Chip Thickness ◽  
Shear Plane ◽  
Shear Angle ◽  
Surface Slope ◽  
Experimental Conditions ◽  
Undeformed Chip Thickness ◽  
Cutting Force Components ◽  
The Mean ◽  
Force Components ◽  
Made In

Previous work has shown that during the removal of a surface waveform oscillating cutting force components arise which may have a phase difference with respect to the oscillating component of undeformed chip thickness; it has also shown that the shear angle is affected by the slopes of the surface waveform. However, no attempt to predict the oscillating force behaviour from the geometry of cutting has been reported. The present work attempts to achieve such a prediction by means of an analysis of the phase and magnitude of the oscillating force components acting in two directions; in the directions of the mean shear plane and of the tool rake face. In the analysis it is assumed that the shear angle oscillates in phase with and proportionally to the surface slope, and that the curvature of the chip varies with the undeformed chip thickness. An experimental technique for cutting with variable undeformed chip thickness is described, together with a method for recording and measuring the oscillating components of force and undeformed chip thickness. Experimental results are presented which show the assumptions made in the analysis to be substantially valid; the predicted oscillating forces are shown to be in adequate agreement with experiment over a range of experimental conditions. It is shown that the oscillation of the shear angle is primarily dependent on the surface slope and that the frictional force behaviour is consistent with the characteristics of the two regions of friction, sticking and sliding, as found in work on cutting with constant undeformed chip thickness.

Machine Tool Chatter: Effect of Surface Slope on Machining Forces During Wave Removing

1974 ◽  
Vol 96 (4) ◽  
pp. 1202-1206 ◽  
Author(s):  
J. F. Sarnicola ◽  
G. Boothroyd
Keyword(s):  
Chip Thickness ◽  
Rate Of Change ◽  
Surface Slope ◽  
Phase Component ◽  
Undeformed Chip Thickness ◽  
Machining Forces ◽  
Work Surface ◽  
Tool Force ◽  
Machine Tool Chatter ◽  
Effect Of Surface

The effect of work surface slope (rate of change of undeformed chip thickness) on machining forces has been measured. The results of these experiments are used to develop equations for the cutting and thrust components of the resultant tool force during wave removing. It is found that the work surface slope effect gives rise to a significant out-of-phase component of the oscillating tool force which should not be neglected in stability analyses.

scholarly journals Influence of the Rake Angle on Nanocutting of Fe Single Crystals: A Molecular-Dynamics Study

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 516 ◽  
Author(s):  
Iyad Alabd Alhafez ◽  
Herbert M. Urbassek
Keyword(s):  
Molecular Dynamics ◽  
Chip Thickness ◽  
Mass Conservation ◽  
Friction Angle ◽  
Rake Angle ◽  
Shear Angle ◽  
Dynamics Simulation ◽  
Burgers Vector ◽  
Edge Dislocations ◽  
Cutting Direction

Using molecular dynamics simulation, we study the cutting of an Fe single crystal using tools with various rake angles α . We focus on the (110)[001] cut system, since here, the crystal plasticity is governed by a simple mechanism for not too strongly negative rake angles. In this case, the evolution of the chip is driven by the generation of edge dislocations with the Burgers vector b = 1 2 [ 111 ] , such that a fixed shear angle of ϕ = 54.7 ∘ is established. It is independent of the rake angle of the tool. The chip form is rectangular, and the chip thickness agrees with the theoretical result calculated for this shear angle from the law of mass conservation. We find that the force angle χ between the direction of the force and the cutting direction is independent of the rake angle; however, it does not obey the predictions of macroscopic cutting theories, nor the correlations observed in experiments of (polycrystalline) cutting of mild steel. Only for (strongly) negative rake angles, the mechanism of plasticity changes, leading to a complex chip shape or even suppressing the formation of a chip. In these cases, the force angle strongly increases while the friction angle tends to zero.

Process-Independent Force Characterization for Metal-Cutting Simulation

1997 ◽  
Vol 119 (1) ◽  
pp. 86-94 ◽  
Author(s):  
D. A. Stephenson ◽  
P. Bandyopadhyay
Keyword(s):  
Metal Cutting ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Baseline Data ◽  
Empirical Equations ◽  
Machining Processes ◽  
Workpiece Material ◽  
Bar Turning ◽  
Force Data

Obtaining accurate baseline force data is often the critical step in applying machining simulation codes. The accuracy of the baseline cutting data determines the accuracy of simulated results. Moreover, the testing effort required to generate suitable data for new materials determines whether simulation provides a cost or time advantage over trial-and-error testing. The efficiency with which baseline data can be collected is limited by the fact that simulation programs do not use standard force or pressure equations, so that multiple sets of tests must be performed to simulate different machining processes for the same tool-workpiece material combination. Furthermore, many force and pressure equations do not include rake angle effects, so that separate tests are also required for different cutter geometries. This paper describes a unified method for simulating cutting forces in different machining processes from a common set of baseline data. In this method, empirical equations for cutting pressures or forces as a function of the cutting speed, uncut chip thickness, and tool normal rake angle are fit to baseline data from end turning, bar turning, or fly milling tests. Forces in specific processes are then calculated from the empirical equations using geometric transformations. This approach is shown to accurately predict forces in end turning, bar turning, or fly milling tests on five common tool-work material combinations. As an example application, bar turning force data is used to simulate the torque and thrust force in a combined drilling and reaming process. Extrapolation errors and corrections for workpiece hardness variations are also discussed.

A New Model and Analysis of Orthogonal Machining With an Edge-Radiused Tool

1999 ◽  
Vol 122 (3) ◽  
pp. 384-390 ◽  
Author(s):  
Jairam Manjunathaiah ◽  
William J. Endres
Keyword(s):  
Shear Stress ◽  
Deformation Zone ◽  
Lower Boundary ◽  
Chip Thickness ◽  
Rake Angle ◽  
Shear Angle ◽  
Force Model ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Machining Force

A new machining process model that explicitly includes the effects of the edge hone is presented. A force balance is conducted on the lower boundary of the deformation zone leading to a machining force model. The machining force components are an explicit function of the edge radius and shear angle. An increase in edge radius leads to not only increased ploughing forces but also an increase in the chip formation forces due to an average rake angle effect. Previous attempts at assessing the ploughing components as the force intercept at zero uncut chip thickness, which attribute to the ploughing mechanism all the changes in forces that occur with changes in edge radius, are seen to be erroneous in view of this model. Calculation of shear stress on the lower boundary of the deformation zone using the new machining force model indicates that the apparent size effect when cutting with edge radiused tools is due to deformation below the tool (ploughing) and a larger chip formation component due to a lower shear angle. Increases in specific energy and shear stress are also due to shear strain and strain rate increases. A consistent material behavior model that does not vary with process input conditions like uncut chip thickness, rake angle and edge radius can be developed based on the new model. [S1087-1357(00)01302-2]

On the Effects of a Built-Up Edge on Acoustic Emission in Metal Cutting

1990 ◽  
Vol 112 (2) ◽  
pp. 184-189 ◽  
Author(s):  
D. V. Hutton ◽  
Qinghuan Yu
Keyword(s):  
Acoustic Emission ◽  
Experimental Evidence ◽  
Deformation Zone ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Rake Angle ◽  
Shear Angle ◽  
Cutting Conditions ◽  
Effective Rake Angle

Experimental evidence is presented which indicates that the presence of a built-up edge can significantly affect the generation of acoustic emission in metal cutting. Results for machining SAE 1018 and 4140 steels show that the built-up edge can mask the generally accepted AE-cutting speed relation when cutting tools having small rake angles are used. Under cutting conditions conducive to development of a built-up edge, it is shown that increased acoustic emission is generated as a result of increased effective rake angle and corresponding increase of shear angle in the primary deformation zone. Three distinct types of built-up edge have been observed and classified as immature, periodic, or developed, according to effect on acoustic emission.

Finite Element Modeling of Chip Formation in the Domain of Negative Rake Angle Cutting

2003 ◽  
Vol 125 (3) ◽  
pp. 324-332 ◽  
Author(s):  
Y. Ohbuchi ◽  
T. Obikawa
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Undeformed Chip Thickness ◽  
Element Modeling ◽  
Single Grain ◽  
Serrated Chips

A thermo-elastic-plastic finite element modeling of orthogonal cutting with a large negative rake angle has been developed to understand the mechanism and thermal aspects of grinding. A stagnant chip material ahead of the tool tip, which is always observed with large negative rake angles, is assumed to act like a stable built-up edge. Serrated chips, one of typical shapes of chips observed in single grain grinding experiment, form when analyzing the machining of 0.93%C carbon steel SK-5 with a rake angle of minus forty five or minus sixty degrees. There appear high and low temperature zones alternately according to severe and mild shear in the primary shear zone respectively. The shapes of chips depend strongly on the cutting speed and undeformed chip thickness; as the cutting speed or the undeformed chip thickness decreases, chip shape changes from a serrated type to a bulging one to a wavy or flow type. Therefore, there exists the critical cutting speed over which a chip can form and flow along a rake face for a given large negative rake angle and undeformed chip thickness.

Experimental Study on the Chip Geometry and Shear Angle in Micro-Cutting Aluminum 7050-T7451

2010 ◽  
Vol 443 ◽  
pp. 657-662
Author(s):  
Jun Zhou ◽  
Jian Feng Li ◽  
Jie Sun
Keyword(s):  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Shear Angle ◽  
Micro Scale ◽  
Effective Rake Angle ◽  
Al 7075 ◽  
Chip Geometry ◽  
Cutting Experiments ◽  
Machining Characteristics

In this paper, the micro-scale machining characteristics of a non-ferrous structural alloy, aluminum 7050-T7451 is investigated through a series of cutting experiments. The effects of cutting speed and undeformed chip thickness on the chip geometry, cutting ratio, effective rake angle and shear angle in orthogonal micro-scale cutting of Al 7075-T7451 are presented. Explanations for the observed trends are also given.

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