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.

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.

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].

Chip Formation With Varying Undeformed Chip Thickness at Very Slow Speed

1964 ◽  
Vol 86 (4) ◽  
pp. 389-394 ◽  
Author(s):  
Shiro Kobayashi ◽  
A. Shabaik
Keyword(s):  
Free Surface ◽  
Chip Thickness ◽  
Shear Plane ◽  
Shear Angle ◽  
Slow Speed ◽  
Angle Variation ◽  
Undeformed Chip Thickness ◽  
State Of Stress ◽  
Rolled Specimen ◽  
Cold Rolled

Steel S.A.E. 1112 cold rolled specimen was cut orthogonally at slow speed of 0.625 ipm, and the shear plane formation was examined from a series of photographs taken during a cut for cutting triangular wavy surface and for the case where the straight surface is cut by the tool moving along the triangular wavy path. It was found that the shear angle variation is approximately given by equation (3) of the text. An explanation for this shear angle variation is provided by the consideration of the state of stress around the singular point at the free surface.

scholarly journals Copaiba oil in experimental wound healing in horses

2017 ◽  
Vol 47 (4) ◽  
Author(s):  
Flavia de Almeida Lucas ◽  
Adriana Lima Kandrotas ◽  
Eugenio Nardin Neto ◽  
Carlos Eduardo de Siqueira ◽  
Gabriela Santo André ◽  
...  
Keyword(s):  
Wound Healing ◽  
Sodium Chloride ◽  
Treatment Group ◽  
Control Group ◽  
Wound Therapy ◽  
Experimental Conditions ◽  
Therapeutic Possibility ◽  
Copaiba Oil ◽  
The Mean ◽  
Made In

ABSTRACT: The aim of this study was to evaluate the effects of 10% copaiba oil in experimentally induced wounds in horses. Four wounds were made in the lumbar and metacarpal regions of eight adult horses. In the treatment group, the wounds received 10% copaiba oil and in the control group 0.9% sodium chloride, in the daily dressing for 21 days. The wounds were evaluated three, 7, 14, and 21 days postoperatively. No significant differences were observed between the groups. The mean lumbar wound contraction rates were 80.54% and 69.64%, for the control and treated groups, respectively. For the wounds in the metacarpal region, these averages were 44.15% and 52.48%, respectively. Under the experimental conditions of the present study, it is concluded that 10% copaiba oil has beneficial in wound healing in the equine species and suggest that copaiba oil can be used as a therapeutic possibility in equine wound therapy.

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.

Experimental Investigations in Cutting Dynamics

1993 ◽  
Vol 115 (4) ◽  
pp. 508-511 ◽  
Author(s):  
K. Marchelek ◽  
J. Tomko´w
Keyword(s):  
Transfer Functions ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Experimental Investigations ◽  
Process Dynamics ◽  
Cutting Force Components ◽  
Force Components ◽  
Additive Influence ◽  
Process Transfer

This paper presents the results of an investigation of cutting process transfer functions in orthogonal cutting. An empirical model of cutting process dynamics with respect to the inner modulation of the chip thickness has been developed. The hypothesis about the independent and additive influence of both inner and outer modulation on the cutting force components has been confirmed.

scholarly journals An investigation of force components in orthogonal cutting of medical grade cobalt–chromium alloy (ASTM F1537)

2017 ◽  
Vol 231 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Szymon Baron ◽  
Eamonn Ahearne
Keyword(s):  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Lifestyle Changes ◽  
Ageing Population ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Undeformed Chip Thickness ◽  
Force Components ◽  
Medical Grade

An ageing population, increased physical activity and obesity are identified as lifestyle changes that are contributing to the ongoing growth in the use of in-vivo prosthetics for total hip and knee arthroplasty. Cobalt–chromium–molybdenum (Co-Cr-Mo) alloys, due to their mechanical properties and excellent biocompatibility, qualify as a class of materials that meet the stringent functional requirements of these devices. To cost effectively assure the required dimensional and geometric tolerances, manufacturers rely on high-precision machining. However, a comprehensive literature review has shown that there has been limited research into the fundamental mechanisms in mechanical cutting of these alloys. This article reports on the determination of the basic cutting-force coefficients in orthogonal cutting of medical grade Co-Cr-Mo alloy ASTM F1537 over an extended range of cutting speeds ([Formula: see text]) and levels of undeformed chip thickness ([Formula: see text]). A detailed characterisation of the segmented chip morphology over this range is also reported, allowing for an estimation of the shear plane angle and, overall, providing a basis for macro-mechanic modelling of more complex cutting processes. The results are compared with a baseline medical grade titanium alloy, Ti-6Al-4V ASTM F136, and it is shown that the tangential and thrust-force components generated were, respectively, ≈35% and ≈84% higher, depending primarily on undeformed chip thickness but with some influence of the cutting speed.

Forces and Energy in Circular Sawing and Grinding of Granite

2000 ◽  
Vol 123 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Xipeng Xu ◽  
Yuan Li ◽  
Stephen Malkin
Keyword(s):  
Normal Force ◽  
Tangential Force ◽  
Chip Thickness ◽  
Undeformed Chip Thickness ◽  
Unit Width ◽  
Wide Range ◽  
Grinding Conditions ◽  
Cutting Zone ◽  
Circular Sawing ◽  
Force Components

An investigation is reported of the forces and energy in circular sawing and grinding of gray granite. Measurements were made of the forces and power over a wide range of sawing and grinding conditions. Calculated tangential force components were found to be much different than the measured horizontal force components for sawing, but the two forces were almost identical for grinding. The location of the resultant force was proportionally further away from the bottom of the cutting zone with longer contact lengths. For sawing, the normal force per grain was nearly proportional to the calculated undeformed chip thickness. The G-ratios at different sawing rates reached a maximum value at the same intermediate undeformed chip thickness, which was attributed to a transition in the diamond wear mechanism from attrition to fracture at a critical normal force per grain. SEM observations indicated material removal mainly by brittle fracture, with some evidence of ductile plowing especially for grinding and to a lesser extent for sawing. The corresponding fracture energy was estimated to constitute a negligible portion of the total energy expenditure. About 30 percent of the sawing energy might be due to the interaction of the swarf with the applied fluid and bond matrix. Most of the energy for sawing and grinding is attributed to ductile plowing. Analogous to recent studies on grinding of ceramics and glass, the power per unit width was found to increase linearly with the generation of plowed surface area per unit width.

Machining Forces: Some Effects of Tool Vibration

1965 ◽  
Vol 7 (2) ◽  
pp. 152-162 ◽  
Author(s):  
P. W. Wallace ◽  
C. Andrew
Keyword(s):  
Thrust Force ◽  
Chip Thickness ◽  
Experimental Results ◽  
Tool Vibration ◽  
Undeformed Chip Thickness ◽  
Speed Range ◽  
Theoretical Predictions ◽  
Thrust Forces ◽  
Good Agreement ◽  
Made In

When tool vibration occurs during machining both the undeformed chip thickness and the cutting forces have oscillating components. An examination of previous work reveals that both the relative phases and amplitudes of the oscillating forces and the oscillating undeformed chip thickness can be affected appreciably by changes in frequency. The explanations for this behaviour which have been put forward are not entirely consistent with previous experimental evidence. In the present work an analysis of the thrust forces occurring during tool vibration is proposed. The analysis is based on the assumption that there are two components to the oscillating thrust force: (1) a component proportional to, and in phase with, the oscillations in undeformed chip thickness and (2) a component, caused by contact between a small area of the tool flank and the freshly cut work surface, which leads the oscillation in undeformed chip thickness by 90°. Experimental results are presented which validate the assumptions made in the analysis. On applying the analysis to present and past experimental results, there is good agreement between theory and experiment when cutting at sufficient speed to prevent the formation of a substantial built-up edge: when cutting within the built-up edge speed range the theoretical predictions are less satisfactory, though still qualitatively correct. The results also show that changes in undeformed chip thickness have a smaller effect on the tool forces under vibratory conditions than under steady conditions.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

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