Diamond Coatings for Machining: Coating Thickness Effects

2009 ◽  
Author(s):  
Feng Qin ◽  
Y. Kevin Chou ◽  
Dustin Nolen ◽  
Raymond G. Thompson
Keyword(s):  
Residual Stresses ◽  
Coating Thickness ◽  
Cutting Forces ◽  
Failure Modes ◽  
Cutting Tools ◽  
Cutting Edge ◽  
The Other ◽  
Diamond Coatings ◽  
Coated Tools ◽  
Other Hand

Chemical vapor deposition (CVD)-grown diamond films have found applications as a hard coating for cutting tools. Even though the use of conventional diamond coatings seems to be accepted in the cutting tool industry, selections of proper coating thickness for different machining operations have not been often studied. Coating thickness affects the characteristics of diamond coated cutting tools in different perspectives that may mutually impact the tool performance in machining in a complex way. In this study, coating thickness effects on the deposition residual stresses, particularly around a cutting edge, and on coating failure modes were numerically investigated. On the other hand, coating thickness effects on tool surface smoothness and cutting edge radii were experimentally investigated. In addition, machining Al matrix composites using diamond coated tools with varied coating thicknesses was conducted to evaluate the effects on cutting forces, part surface finish and tool wear. The results are summarized as follows. (1) Increasing coating thickness will increase the residual stresses at the coating-substrate interface. (2) On the other hand, increasing coating thickness will generally increase the resistance of coating cracking and delamination. (3) Thicker coatings will result in larger edge radii; however, the extent of the effect on cutting forces also depends upon the machining condition. (4) For the thickness range tested, the life of diamond coated tools increases with the coating thickness because of delay of delaminations.

The Vertical Agreements Regulation: A Critical Appraisal

2000 ◽  
Vol 3 ◽  
pp. 525-545
Author(s):  
Paul M. Taylor
Keyword(s):  
Competition Policy ◽  
Critical Appraisal ◽  
Cutting Edge ◽  
The Other ◽  
Other Hand ◽  
Progressive Policy ◽  
The One

The Vertical Agreements Regulation may be judged in one of two ways, each yielding a different conclusion. It may be regarded, on the one hand, merely as a limited measure required at a particular time in the development of competition policy to correct some of the more obvious errors of previous Regulations. On the other hand, it may be assessed for its potential as a template for future Regulations. Is it to be regarded as a means of rectifying historic block exemptions or is it at the cutting edge of progressive policy? Without doubt it appears chronologically at one of the most important shifts in competition policy in decades and that is why there is much to be gained from reviewing the Regulation critically for improvements that can be carried forward into future Regulations.

3. Contracts of employment (2): content and wages

2019 ◽  
pp. 138-253
Author(s):  
Ian Smith ◽  
Aaron Baker ◽  
Owen Warnock
Keyword(s):  
Social Media ◽  
Minimum Wage ◽  
Electronic Communication ◽  
Employment Law ◽  
Cutting Edge ◽  
The Other ◽  
Living Wage ◽  
Employment Contracts ◽  
Other Hand ◽  
The Law

This chapter explores where express terms come from, especially if they are not all neatly set out in writing, and then goes on to consider how terms become implied. Here, several significant differences between ordinary commercial contracts and employment contracts will be seen, both in the scale of the use of implied terms in employment law to ‘perfect’ the bargain and in the sheer strength of some of these frequently implied terms that can, in practice, be just as important as express terms. Having looked at where these terms come from, the chapter goes on to consider the principal duties that they impose on employers and employees, some of which are old and obvious, such as the employer’s duty to pay wages and the employee’s duty of obedience to lawful orders. On the other hand, some are more recent and more at the cutting edge of modern employment law, such as the implied term of trust and confidence for the employee and the topical controversies over confidentiality at work in an age of electronic communication and social media. The chapter concludes by considering specifically the law on wages, including the statutory requirements of paying the national minimum wage and the national living wage.

Thermal-Mechanical Contact of a Sphere on a Layered Surface

2010 ◽  
Author(s):  
Wenping Song ◽  
Andrey Ovcharenko ◽  
Guangyu Zhang ◽  
Frank E. Talke
Keyword(s):  
Layer Thickness ◽  
Coating Thickness ◽  
Temperature Rise ◽  
Material Properties ◽  
Mechanical Deformation ◽  
The Other ◽  
Mechanical Contact ◽  
Other Hand ◽  
Transient Thermal

The effect of coating thickness is investigated during transient thermal-mechanical contact between a sphere and a layered surface. The range of coating thicknesses studied was from 0.001≤t/R≤0.1, where t is the coating thickness and R is the radius of the contacting sphere. It was found that for the range of coating thickness and material properties investigated, the coating thickness has only a small effect on the mechanical deformation of the interface. On the other hand, the layer thickness has a large effect on the temperature rise of the interface.

Influence of Reground Tool Sharpness on Micro-Cutting Process

2010 ◽  
Vol 37-38 ◽  
pp. 550-553
Author(s):  
Xin Li Tian ◽  
Zhao Li ◽  
Xiu Jian Tang ◽  
Fang Guo ◽  
Ai Bing Yu
Keyword(s):  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Cutting Process ◽  
Micro Cutting ◽  
Temperature Distributions ◽  
Edge Radius ◽  
1045 Steel

Tool edge radius has obvious influences on micro-cutting process. It considers the ratio of the cutting edge radius and the uncut chip thickness as the relative tool sharpness (RST). FEM simulations of orthogonal cutting processes were studied with dynamics explicit ALE method. AISI 1045 steel was chosen for workpiece, and cemented carbide was chosen for cutting tool. Sixteen cutting edges with different RTS values were chosen for analysis. Cutting forces and temperature distributions were calculated for carbide cutting tools with these RTS values. Cutting edge with a small RTS obtains large cutting forces. Ploughing force tend to sharply increase when the RTS of the cutting edge is small. Cutting edge with a reasonable RTS reduces the heat generation and presents reasonable temperature distributions, which is beneficial to cutting life. The force and temperature distributions demonstrate that there is a reasonable RTS range for the cutting edge.

Regenerative Chatter Vibration Occurring in Turning With Different Side Cutting Edge Angles

1995 ◽  
Vol 117 (4) ◽  
pp. 551-558 ◽  
Author(s):  
E. Marui ◽  
M. Hashimoto ◽  
S. Kato
Keyword(s):  
Energy Supply ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Edge ◽  
The Other ◽  
Chatter Vibration ◽  
Regenerative Chatter ◽  
Edge Angle ◽  
Regenerative Effect ◽  
Two Factors

This paper deals with the regenerative chatter vibration occurring in cutting tools with different side cutting edge angles. The occurrence of regenerative chatter vibration of the cutting tool is influenced by two factors, which are closely related to the vibratory energy supply or consumption. One factor is the interference effect between the tool flank and the workpiece. Of course, this factor exists in the primary chatter, too. The other is the regenerative effect. The influence of both factors on the regenerative chatter vibration of cutting tools with different side cutting edge angles is examined experimentally. The vibratory energy supply is simulated, considering the dynamic cutting process. As a result, the property of the regenerative chatter vibration and the influence of the side cutting edge angle on the regenerative chatter vibration are clarified.

scholarly journals RESEARCH ON SHEAR PERFORMANCE OF COMPONENTS CONNECTED BY BEECH AND SELF-TAPPING SCREW COMPOSITE DOWELS

Wood Research ◽  
2021 ◽  
Vol 66 (6) ◽  
pp. 955-968
Author(s):  
XUDONG ZHU ◽  
YINGYING XUE ◽  
XUEWEN ZHANG ◽  
PENGFEI QI ◽  
JIE SHEN ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Linear Equation ◽  
Failure Modes ◽  
Maximum Load ◽  
The Other ◽  
Test Results ◽  
Other Hand ◽  
Shear Performance ◽  
Group B ◽  
Better Than

This study examined the properties of components connected by beech and self-tapping screw composite dowels (group C). As a contrast, the components connected by beech dowels and self-tapping screws individually were tested. The test results indicated that the properties of the components connected by beech dowels (group B) were better than those connected by self-tapping screws (group S), except the ductility coefficient, final displacement, and energy consumption. On the other hand, the main failure modes of groups B and S were the broken beech dowel and the bent self-tapping screw, respectively. For group C, two peak values could be found which were larger than the maximum load of groups B and S, respectively. The properties of group C were better than those of groups B and S, except that the final displacement and energy consumption were located between those of groups B and S. Meanwhile, the linear equation in two unknowns have be found between groups B, S and C.

scholarly journals An analysis on paradoxical gender equality+ policies and the violence in Brazil

2020 ◽  
pp. 291-308
Author(s):  
Renan de Souza
Keyword(s):  
Gender Equality ◽  
Violence Against Women ◽  
Cutting Edge ◽  
The Other ◽  
Gender Based Violence ◽  
Far Right ◽  
Other Hand ◽  
The World ◽  
Gender Based ◽  
Made In

Brazil records alarming rates of epidemic violence against women and LGBTQ+. According to statistics, the country ranks as the fifth most violent for women and the deadliest in the world for homosexuals. On the other hand, progressive policies to support both groups have been implemented by different public administrations in the last decades generating remarkable milestones. Despite being considered as cutting-edge, those actions have not necessarily translated into a reduction of violence. One explanation for these paradoxes between progressive policies to protect women, LGBTQ+ and the frequent violence against these groups, might be found in historical, cultural, and religious roots. This article highlights that, notwithstanding that some progress was made in Brazil, the rise of conservative and far-right groups may undermine all the advancement reached in the last decades, which could lead to the aggravation of the gender-based violence in the country

A Numerical Study to Investigate the Influence of Edge Preparation in Vibration Assisted Machining

2018 ◽  
Author(s):  
Salman Pervaiz ◽  
Sathish Kannan ◽  
Wael Abdel Samad
Keyword(s):  
Cutting Forces ◽  
Small Amplitude ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Numerical Study ◽  
Cutting Tools ◽  
Cutting Edge ◽  
Internal Stresses ◽  
Machining Performance ◽  
Edge Preparation

In machining operation, cutting tool performs a central role towards the overall machining performance. A user from metal cutting community always look for better cutting tools that can enhance productivity by reducing tool wear and cost. Modification in the micro-geometry of cutting edge is termed as edge preparation, and it is performed to improve the machining performance by strengthening the cutting edge, reducing internal stresses of coating and lowering the edge chipping etc. Edge preparation has a controlling influence on the formation of deformation zones, cutting temperature, cutting forces and stresses at the cutting interface. Vibration assisted machining (VAM) concept is gaining fame in the metal cutting sector community for machining difficult-to-machine materials. In VAM, cutting tool moves with a small amplitude vibration instead of moving with a constant cutting velocity. This small amplitude vibrational movement provides better machining performance for difficult-to-cut brittle materials. The current numerical study utilized different edge prepared micro-geometries such as sharp edge, round edge and chamfer edge etc. cutting tools, and then these cutting tools were used in the numerical simulations of VAM. The study shows higher magnitude of cutting forces under VAM with tools with modified geometry. The study is beneficial for the metal cutting community and opens new areas of industrial applications.

Effect of tool wear on chip formation during dry machining of Ti-6Al-4V alloy, part 2: Effect of tool failure modes

2015 ◽  
Vol 231 (9) ◽  
pp. 1575-1586 ◽  
Author(s):  
Shoujin Sun ◽  
Milan Brandt ◽  
Matthew S Dargusch
Keyword(s):  
Plastic Deformation ◽  
Tool Wear ◽  
Failure Modes ◽  
Flank Wear ◽  
Cutting Tools ◽  
Cutting Edge ◽  
Machined Surface ◽  
Tool Failure ◽  
Geometric Ratio ◽  
Cutting Speeds

Variation in the geometric and surface features of segmented chips with an increase in the volume of material removed and tool wear has been investigated at cutting speeds of 150 and 220 m/min at which the cutting tools fail due to gradual flank wear and plastic deformation of the cutting edge, respectively. Among the investigated geometric variables of the segmented chips, slipping angle, undeformed surface length, segment spacing, degree of segmentation and chip width showed the different variation trends with an increase in the volume of material removed or flank wear width, and achieved different values when tool failed at different cutting speeds. However, the chip geometric ratio showed a similar variation trend with an increase in the volume of material removed and flank wear width, and achieved the similar value at the end of tool lives at cutting speeds of both 150 and 220 m/min regardless of the different tool failure modes. Plastic deformation of the tool cutting edge results in severe damage on the machined surface of the chip and significant compression deformation on the undeformed surface of the chip.

Sources and Consequences of Residual Stresses due to Welding

2014 ◽  
Vol 783-786 ◽  
pp. 2777-2785 ◽  
Author(s):  
Thomas Nitschke-Pagel ◽  
Klaus Dilger
Keyword(s):  
Residual Stresses ◽  
The Other ◽  
Production Factor ◽  
Other Hand ◽  
Welding Processes

A detrimental parameter which is always connected with welding processes is the distortion which may occur in welded components. The reduction of distortion is a very costly production factor and in complex constructions the disposal of the distortion might be very complicate or even impossible. On the other hand we know that every step which is done to increase the stiffness of a welded component in order to avoid distortion is connected with the possibility of the generation of higher tensile residual stresses.

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