Critical Review of Some Previous Work on the Mechanics of the Metal-Cutting Process

1968 ◽  
Vol 90 (1) ◽  
pp. 54-62 ◽  
Author(s):  
J. A. Bailey ◽  
G. Boothroyd
Keyword(s):  
Metal Cutting ◽  
Friction Stress ◽  
Rake Angle ◽  
Cutting Process ◽  
Linear Relationships ◽  
The Mean ◽  
The Difference ◽  
Two Parameters ◽  
Relationship Of ◽  
Continuous Chip

A review is presented concerning the mechanics of the metal-cutting process where a continuous chip is produced with the absence of a built-up edge on the tool face. It is shown that previous theories which predicted a linear relationship of the form φ = A − B (β − α) between the angle parameters cannot be used to interpret the experimental data. The apparent linear relationships observed in some previous experimental work are thought to be due partly to the method of presentation of the results. It is suggested that a more significant combination of the angle parameters is the difference between the shear angle φ and the rake angle α, that is, (φ − α). It is pointed out that two parameters which can be used to describe the frictional conditions on the tool face are the mean friction stress and the mean normal stress. Since these can vary independently, it is thought unrealistic to group them together as a single variable. It is therefore concluded that the mean angle of friction is insufficient in itself to describe the frictional conditions on the tool face.

Effects of Strain Rate and Temperature in Orthogonal Metal Cutting

1966 ◽  
Vol 8 (3) ◽  
pp. 264-275 ◽  
Author(s):  
G. Boothroyd ◽  
J. A. Bailey
Keyword(s):  
Theoretical Analysis ◽  
Strain Rate ◽  
Metal Cutting ◽  
Single Phase ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Rake Angle ◽  
Cutting Process ◽  
Strain Rates ◽  
Continuous Chip

A new theoretical analysis of the orthogonal cutting process is described which is based on the known behaviour of a single phase metal at high strains, strain rates and temperatures. The theoretical analysis applies to the case where a continuous chip is produced under non-lubricated conditions with the absence of a built-up edge on the tool face and indicates the important parameters in the cutting process. The theory is examined experimentally and its validity established. Finally, from a knowledge of the effects of strain rate and temperature on the yield stress of a single phase metal, the theory is used to predict the effects of changes in cutting speed and tool rake angle on the tool forces and geometry of the cutting process. These predictions are compared qualitatively with the results of cutting tests.

The Effect of Prior Cutting Conditions on the Shear Mechanics of Orthogonal Machining

1998 ◽  
Vol 120 (1) ◽  
pp. 13-20 ◽  
Author(s):  
R. Stevenson ◽  
D. A. Stephenson
Keyword(s):  
Material Properties ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Rake Angle ◽  
Cnc Machining ◽  
Machining Process ◽  
Depth Of Cut ◽  
Prior History ◽  
Machining Conditions ◽  
The Difference

It has been proposed several times in the metal-cutting literature that the machining process is non-unique and that the instantaneous machining conditions depend on the prior machining conditions (e.g. depth of cut, rake angle etc.). To evaluate the validity of this concept, a series of experiments was conducted using a highly accurate CNC machining center. For these experiments, the machining conditions were changed during the course of an orthogonal cutting experiment in a repeatable manner and the measured forces compared as a function of prior history. Tests were conducted on several tempers of 1100 aluminum and commercial purity zinc to evaluate the effect of material properties on the machining response. It was found that the change in measured cutting forces which could be ascribed to prior machining history was less than 3 percent and that material properties, particularly work hardening response, had no discernible effect on the magnitude of the difference.

scholarly journals RELATIONSHIP OF ELECTRICAL RESISTANCE OF VAGINAL MUCUS DURING OESTRUS WITH POST-AI PREGNANCY IN COWS

2018 ◽  
Vol 15 (2) ◽  
pp. 113-117 ◽  
Author(s):  
M. Ahmed ◽  
M. K. Chowdhury ◽  
M. M. Rahman ◽  
J. Bhattacharjee ◽  
M. M. U. Bhuiyan
Keyword(s):  
Pregnancy Rate ◽  
Electrical Resistance ◽  
Genital Tract ◽  
Conception Rate ◽  
Heat Detector ◽  
The Mean ◽  
The Difference ◽  
Rectal Palpation ◽  
Relationship Of ◽  
In Pregnancy

Accurate detection of oestrus is a common problem for farmers to do AI timely resulting in conception failure in cows. The objective of the present study was to know the electrical resistance of vaginal mucus (ERVM) during oestrus to determine the best time of AI for improvement of conception in cattle. A total of 28 cows were inseminated with frozen thawed semen after detection of ERVM with Draminski estrus detector at Kendua Upazila Livestock Office under Netrakona district of Bangladesh. Pregnancy was diagnosed by per rectal palpation of genital tract 8-10 weeks after insemination. The mean ERVM in pregnant cows was 208.5 ± 31.2 Ω (163.3 to 263.3 Ω) and the ERVM in non-pregnant cows was 214.4 ± 36.6 Ω (153.3 to 280.0 Ω). Moreover, the pregnancy rate was higher in cows (80.0 to 83.3%) when ERVM during oestrus varied from 150 to 220 Ω than that of 221 to 280 Ω counterpart (36.4%). The difference in pregnancy rates between groups was significant (P<0.05). The present study indicates that Dramniski electrical heat detector may be used for prediction of time for AI in cows of Bangladesh. Up to 220 Ω ERVM during oestrus is better for higher conception rate than that of more than 220 Ω counterparts. Further studies with high number of inseminated cows should be conducted before wide application of this electrical heat detector under field conditions in Bangladesh.

Multi-Constrained Analysis of Metal Cutting and its Application

2013 ◽  
Vol 589-590 ◽  
pp. 38-44
Author(s):  
Gang Liu ◽  
Ming Chen ◽  
Peng Nan Li ◽  
Qing Zhen Bi ◽  
Bao Cai Guo
Keyword(s):  
Thermal Conductivity ◽  
Stainless Steel ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Rake Angle ◽  
Cutting Process ◽  
Optimization Strategy ◽  
First Time

The concept of multi-constrained analysis of the cutting process is presented for the first time in the paper. The paper adopts a method to solve an important problem which is how to judge the influence of constrains during the cutting process. The research results are applied for HSS drills for cutting stainless steel. On the basis of the multi-constrained analysis combined with methods of simulations and standard experiments, the optimum methods are provided for structure, coating and cutting parameters of cutting tools. For geometric structure of tools, optimization is to increase thickness of cutting and rake angle. Coating optimization strategy is choosing high temperature hardness and low thermal conductivity coating. Optimization of cutting parameter is to adjust feed fate, then select proper cutting speed. The conclusion of paper is helpful for the cutting optimization.

Simulation Research on the Metal Cutting Process

2013 ◽  
Vol 641-642 ◽  
pp. 277-280
Author(s):  
Cheng Lei ◽  
Shou Ne Xiao ◽  
Shi Hui Luo
Keyword(s):  
Finite Element ◽  
Metal Cutting ◽  
Three Dimensional ◽  
Element Model ◽  
Rake Angle ◽  
Friction Model ◽  
Cutting Process ◽  
Simulation Research ◽  
Finite Element Software ◽  
Explicit Analysis

The three-dimensional explicit dynamic analysis of metal cutting process is done using the non- linear finite element software LS-DYNA. In the finite element model, 8- node 3D solid element based on one- point integration Lagrangian formulation is adopted, metal material is modeled with Johnson-Cook constitutive model, chip separation is simulated using the material failure criterion of Johnson and Cook proposed and combing the failure element deletion method, friction model of chip-tool contact interface is developed to simultaneously account for sticking and sliding situation. Through explicit analysis, rake angle, cutting depth, and cutting width on the shape of the chip influence are obtained.

scholarly journals A Technique to Determine the Radius of Maximum Wind of a Tropical Cyclone

2008 ◽  
Vol 23 (5) ◽  
pp. 1007-1015 ◽  
Author(s):  
France Lajoie ◽  
Kevin Walsh
Keyword(s):  
High Resolution ◽  
Tropical Cyclone ◽  
Simple Technique ◽  
Cloud Data ◽  
Maximum Wind ◽  
Wind Structure ◽  
The Mean ◽  
The Difference ◽  
Two Parameters ◽  
National Hurricane Center

Abstract A simple technique is developed that enables the radius of maximum wind of a tropical cyclone to be estimated from satellite cloud data. It is based on the characteristic cloud and wind structure of the eyewall of a tropical cyclone, after the method developed by Jorgensen more than two decades ago. The radius of maximum wind is shown to be partly dependent on the radius of the eye and partly on the distance from the center to the top of the most developed cumulonimbus nearest to the cyclone center. The technique proposed here involves the analysis of high-resolution IR and microwave satellite imagery to determine these two parameters. To test the technique, the derived radius of maximum wind was compared with high-resolution wind analyses compiled by the U.S. National Hurricane Center and the Atlantic Oceanographic and Meteorological Laboratory. The mean difference between the calculated radius of maximum wind and that determined from observations is 2.8 km. Of the 45 cases considered, the difference in 50% of the cases was ≤2 km, for 33% it was between 3 and 4 km, and for 17% it was ≥5 km, with only two large differences of 8.7 and 10 km.

scholarly journals Relationship of Physiotherapy Intervention and the Level of Community Reintegration of Stroke Survivors In Accra, Ghana

2021 ◽  
Vol 3 (1) ◽  
pp. 31-39
Author(s):  
Dorcas Kyela Yusuf ◽  
◽  
Samuel Koranteng Kwakye ◽  
Jonathan Quartey ◽  
◽  
...  
Keyword(s):  
P Value ◽  
Stroke Survivors ◽  
Community Reintegration ◽  
Chi Square ◽  
Disability Score ◽  
End Point ◽  
Physiotherapy Intervention ◽  
The Mean ◽  
The Difference ◽  
Relationship Of

Background: Stroke is one of the major causes of death and disability in the world. During rehabilitation, there appears to be little or no emphasis placed on reintegrating the stroke survivors into their communities.The study sought out to determine the relationship between physiotherapy and the level of community reintegration among stroke survivors.Method: This observational study involved51 stroke survivors referred to physiotherapy departments of selected hospitals in Accra. Participants completed the Reintegration to Normal Living Index and the Modified Rankin Scale at baseline and after 8 weeks of physiotherapy sessions. Wilcoxon’s test was used to assess the difference between the baseline and end point scores for reintegration and disability while Chi square and Spearman correlation were used to test for associations between physiotherapy intervention and community reintegration. A p-value of 0.05 was set.Results: The mean reintegration score at baseline was 55.5±17.00 and 76±14.00 at end point (p = 0.001) while the mean disability score at baseline was 3.43±0.67 and 2.31±0.68 at end point (p = 0.001) showing a significant level of improvement from baseline to endpoint of the reintegration and disability scores. There was a low association between duration of stroke (p=0.008) and duration of physiotherapy (p=0.038) with regards to reintegration 8 weeks post physiotherapy.Conclusion: Physiotherapy plays a role in the reintegrating of stroke survivors into their communities. Incorporation of community reintegration into rehabilitation programmes for stroke survivors could be useful. Efforts to include physiotherapy to reintegrate stroke survivors could therefore be strengthened

scholarly journals Finite Element Modeling of the Effect of Tool Rake Angle on Cutting Force and Tool Temperature during High Speed Machining of AISI 1045 Steel

2014 ◽  
Vol 939 ◽  
pp. 194-200
Author(s):  
Shamsuddin Sulaiman ◽  
Mohd K.A. Ariffin ◽  
A. Roshan
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
High Speed ◽  
Metal Cutting ◽  
Rake Angle ◽  
Cutting Process ◽  
High Speed Machining ◽  
Tool Temperature ◽  
Aisi 1045 ◽  
Cutting Speeds

A finite element model (FEM) of an orthogonal metal-cutting process is used to study the influence of tool rake angle on the cutting force and tool temperature. The model involves Johnson-Cook material model and Coulomb’s friction law. A tool rake angle ranging from 0° to 20° and a cutting speed ranging from 300 to 600 m/min were considered in this simulation. The results of this simulation work are consistent optimum tool rake angle for high speed machining (HSM) of AISI 1045 medium carbon steel. It was observed that there was a suitable rake angle between 10° and 18° for cutting speeds of 300 and 433 m/min where cutting force and temperature were lowest. However, there was not optimum rake angle for cutting speeds of 550 and 600 m/min. This paper can contribute in optimization of cutting tool for metal cutting process.

Investigations of Nonlinear Forces in Metal Cutting

2006 ◽  
Vol 2 (1-2) ◽  
pp. 59-79 ◽  
Author(s):  
Emily Stone ◽  
Abe Askari ◽  
Hong Tat
Keyword(s):  
Metal Cutting ◽  
Penetration Rate ◽  
Cutting Speed ◽  
Rake Angle ◽  
Type Model ◽  
Vibration Direction ◽  
Effective Rake Angle ◽  
Force Variation ◽  
The Difference ◽  
Chip Load

During chatter in metal cutting the tool vibration would cause a variation in “effective” rake angle of the cutter, generating a force variation that depends on penetration rate: a kind of process damping. This effect is examined for forces computed both from a theoretical Merchant-type model, and from a numerical database of forces for metal cutting constructed from a suite of AdvantEdge simulations. Since the tool can potential vibrate at any angle relative to the workpiece, the forces for varying angle of vibration were computed, and the dynamic stability consequences considered. It is found that the two models lead to similar forces for varying vibration angle, at least through first order. Depending on the vibration angle the force will either increase or decrease with both chip load and penetration rate, reflecting the difference in the effect on the chipload and cutting speed with varying vibration direction. Second order terms in penetration rate were different in the two formulations, possibly a result of approximations used in the calculations involved in the Merchant formulation. Dynamically this means that the linear stability of each vibration angle is the similar for the two models, while the differences in nonlinear terms results in differences in the type Hopf bifurcation observed upon loss of stability.

Automated Detection of Neutrophil Dysplasia for the Screening of Myelodysplasia and Myelodysplastic Syndromes.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4892-4892 ◽  
Author(s):  
Thilo Wiesent ◽  
Ludwig von Weikersthal ◽  
Nuria Pujol
Keyword(s):  
Bone Marrow ◽  
Myelodysplastic Syndromes ◽  
Hodgkin Disease ◽  
Staining Procedure ◽  
Clinical Value ◽  
Reference Limit ◽  
The Mean ◽  
The Difference ◽  
Hematopoietic Disorders ◽  
Two Parameters

Abstract The myelodysplastic syndromes (MDS) are clonal hematopoietic disorders characterized by cytopenia and bone marrow dysplasia. This is the result of proliferation, differentiation and apoptotic processes of hematopoietic precursors and it frequently evolves to acute myeloid leukemia (AML). The diagnosis of MDS is essentially morphological and is based on the presence of dysplastic features in peripheral blood and bone marrow. The most reliable features of MDS include the presence of micromegakariocytes in the bone marrow and trilineage dysplasia with a high precentage of blast, or cytogenetic abnormalities (1). One of the morphological features that is easily assessed and therefore often used is the presence of dysgranulopoiesis, such as degranulation of the neutrophil population and/or Pelger-Huët-like anomaly. The Coulter LH750® is an automated hematology analyze, that reports a CBC and a six part WBC differential. The technology of the WBC differential use a combination of three measurements, Volume, Conductivity and Scatter, to measure the WBC in a near native state. The possibility to detect the degranulation with the Mean Conductivity of the Neutrophils (MNEC) and the Mean Scatter of the neutrophils (MNES), measured with the LH750® (2,3) and the difference between degranulated neutrophils and immature netrophils (3) has been published. We were interested to investigate other aspects of these parameters, firstly to determine the variability and the positive predictive value of MNEC and MNES, and secondly to assess the clinical value of measuring them on all routine samples. We determined the reference values for the parameters and applied the lower reference limit (2.5th percentile) for MNEC (<138) and for MNES (<139) to 200 samples from a routine daily worload. Five sample had both low MNEC and low MNES and the history of these patients were: Patient 1) NHL in CR after Chemoterapy (CHT) (5 months without treatment). Patient 2) Hodgkin Disease in CR after 3 year of BEACOOP (dysplasia) Patient 3) Hodgkin Disease in CR receiving ABVD (2 years without treatment). Patient 4) Severe Reumathologic disease in treatment with Methotrexate Patient 5) Vasculitis in treatment with Cyclophosphamid and secondary MDS. We reviewed the granulation of the netrophils in the 5 positive cases and also in 5 normal controls from the same day, using the same staining procedure. There was a significant decrease of neutrophil granulation with more than 10% of degranulated neutrophils in all of the positive cases compared to the contols. The variability of the two parameters were analyzed in a patient with a myelodysplastic syndrome (see case used for that in he figure enclosed), and the coefficient of variation for the MNEC was 1,5% and for the MNES was 1%. The Mean Conductivity and the Mean Scatter of the neutrophils, measured using VCS technology, appear to be useful in screening neutrophil dysplasia and their reproducibility suggests that they could be used to screen myelodysplastic syndromes. Figure Figure

Sign in / Sign up

Export Citation Format

Share Document