Transient Thermal Stresses in the Quarter-Plane and their Relation to the Thermal-Cracking of Cutting Tools

1974 ◽  
Vol 16 (5) ◽  
pp. 322-330
Author(s):  
P. F. Thomason
Keyword(s):  
Metal Cutting ◽  
Thermal Stresses ◽  
Cutting Tool ◽  
Crack Nucleation ◽  
Cutting Tools ◽  
Thermal Cracking ◽  
Quarter Plane ◽  
Metal Cutting Tool ◽  
Transient Thermal ◽  
Cemented Carbide Tools

The transient thermal stresses in an insulated quarter-plane, subject to an instantaneous heat source on a segment of the surface, are determined with the aid of the Green's function for a two-dimensional infinite space. Numerical results for the transient thermal stresses at the surfaces of the quarter-plane are superimposed on previous isothermal results for cutting-load stresses in a π/2 wedge, to provide a model for a metal-cutting tool in the transient stages of a cutting process. The results are related to the problem of the thermal-cracking of cutting tools, and mechanisms of crack nucleation and propagation are proposed for both ceramic and cemented-carbide tools.

Methods of Forecasting Wear Resistance of Cutting Tools Based on the Properties of their Materials

2014 ◽  
Vol 682 ◽  
pp. 491-494 ◽  
Author(s):  
Vladislav Bibik ◽  
Elena Petrova
Keyword(s):  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Chemical Properties ◽  
Tool Material ◽  
Composition Structure ◽  
Metal Cutting Tool ◽  
Physical And Chemical ◽  
Thermo Physical Properties

The author considers methods of forecasting metal-cutting tool life based on characteristics of cutting tool material. These characteristics depend on differences in numerical values of physical and chemical properties of tool material due to changes in its composition, structure, and production process variables. The described methods allow obtaining the information necessary for forecasting the tool life beyond the process of cutting, for example at the stage of cutting tool manufacturing. The author suggests using the method of registration of thermo-physical properties of the tool material as a promising forecasting technique.

Report 9: Measurement of Transient Surface Temperatures in Metal Cutting

1967 ◽  
Vol 182 (7) ◽  
pp. 68-70
Author(s):  
P. M. Braiden
Keyword(s):  
Metal Cutting ◽  
Thermal Stresses ◽  
Cutting Tool ◽  
Temperature Record ◽  
Carbide Cutting Tool ◽  
Tool Surface ◽  
Temperature Records ◽  
Metal Cutting Tool ◽  
Intermittent Cutting ◽  
Cooling Part

This report is concerned with measuring the varying thermal stresses in a metal-cutting tool, due to the temperature variations occurring at the tool-chip interface, in the course of intermittent cutting operations. During cutting, the tool is rapidly heated, developing compressive thermal stresses in addition to the mechanical stresses due to the cutting action, but during the non-cutting, or cooling, part of the cycle these latter stresses are absent, and a tensile stress develops on the tool surface. It is believed that these rapidly alternating stresses lead to tool failure by eventual chipping of the cutting edge. The temperature at the interface is measured by means of the tool-work thermocouple technique, in which a tungsten carbide cutting tool contacts a steel workpiece, thereby forming the hot junction of a thermocouple system. The technique is well established for temperature measurements during continuous cutting operations, but care must be taken if it is to provide reliable results. The extension of the technique to include intermittent processes is described, and results are shown for processes having a frequency of 15 c/s. Cutting times as small as 0·026 s have been used and temperature records for this, and greater cutting times, are presented. A disadvantage of this method is that a temperature record is obtained only whilst the tool and work are in contact, and a method to overcome this is outlined.

scholarly journals Influence of Thickness of Multilayer Composite Nano-structured Coatings on Tool Life of Metal-Cutting Tool

2019 ◽  
Vol 224 ◽  
pp. 05011
Author(s):  
Catherine Sotova ◽  
Nikolay Sitnikov ◽  
Jury Bublikov ◽  
Gaik Oganyan ◽  
Andre D.L. Batako
Keyword(s):  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Coated Tools ◽  
Tool Coating ◽  
Cutting Inserts ◽  
Metal Cutting Tool ◽  
Different Thickness ◽  
Cutting Modes ◽  
Strength Of Adhesion

The paper is focused on turning of structural steels C45. Cutting tools were represented by carbide cutting inserts without coatings, with reference coating TiAlN, as well as with multilayered composite nano-structured coatings Ti-TiN-(TiCrAl)N and Zr-ZrN-(ZrCrNbAl)N (of different thickness of 3-7 μm). The following studies of the properties of coated tools were carried out: measurement of microhardness and strength of adhesion bonds in the “tool-coating” system and investigation of elemental and phase compositions of coatings. The cutting tests were carried out at the following cutting modes: f = 0.2 mm/rev; аp = 1.0 mm; vc = 200, 250, 300, 350 and 400 m/min.

scholarly journals Processing of critical parts of marine vessels and structures by metal cutting tools

2021 ◽  
pp. 13-17
Author(s):  
Б.Я. Мокрицкий ◽  
В.М. Давыдов
Keyword(s):  
Service Life ◽  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Software Environment ◽  
Machined Surface ◽  
Metal Cutting Tool ◽  
Marine Vessels

Актуальность. Изложены результаты совершенствования токарной обработки заготовок ответственных деталей морских судов, особенно подводных, и сооружений, подвергаемых в процессе эксплуатации агрессивному воздействию морской воды, например, валопроводов судов. Такие детали, как правило, выполняются из специализированных труднообрабатываемых нержавеющих сталей. Специфические свойства таких сталей создают серьёзные сложности при их обработке лезвийным металлорежущим инструментом. Например, период стойкости типового токарного резца отечественных или зарубежных изготовителей не превышает 40 минут. Это не приемлемо для сегодняшнего уровня высокопроизводительной обработки. Целью работы является повышение эффективности токарной обработки таких сталей. Решение этой задачи достигнуто за счёт разработки новых покрытий для таких режущих пластин. Методы исследования. Для разработки использовано имитационное моделирование как метод исследования. Оно выполнено в программной среде Deform. Она адаптирована под решаемую задачу. Результаты. Разработан металлорежущий инструмент с покрытиями, обеспечивающий повышение периода стойкости в 2 и более раз. Вывод. Поставленная цель достигнута. Обеспечено повышение периода стойкости металлорежущего инструмента в 2 и более раз без снижения производительности обработки и с повышением качества поверхности обработанной заготовки детали. The relevance of the research is due to the fact, that a number of parts of marine vessels and structures must be made of corrosion-resistant steels. These are specialized stainless steels. They have a lot of chrome and nickel. It makes difficult to process blanks of details by metal-cutting tools. Its durability period is insufficient. The aim of the research is to increase the efficiency of turning such steels. Efficiency here means an increasing of the service life of a metal-cutting tool without decreasing of the processing performance and the quality of the machined surface of the detail. The software environment Deform was used as a method of the simulation research. Initial and output criterias have been developed for it. For this purpose, the software environment is adapted to the solving problem. As input parameters, the architecture of the coating is set, when applied to the hard-alloy material, an increase of the tool life is expected. The following results were obtained. Coatings for turning tools, providing the increase of the tool life to 2 or more times, were designed. The output. The setted goal has been achieved. The service life of the metal-cutting tool is increased to 2 or more times without decreasing of the processing performance and with an increase of the surface quality of the processed details.

Steady-State Thermal Stresses in Wedge-Shaped Cutting Tools

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Equivalent Stress ◽  
Cutting Tools ◽  
Thermoelastic Stress ◽  
Plastic State ◽  
Steady State Heat

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.

Hard Nano-Crystalline Coatings for Cutting Tools

2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Dry Cutting ◽  
Nano Crystalline ◽  
The Right ◽  
Machining Productivity ◽  
Hard Cutting ◽  
Cutting Tool Materials

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.

scholarly journals SYSTEM FOR CONTROLLING MASS BALANCE OF GASES AND REAGENTS DURING FORMATION OF ION-PLASMA COATINGS

2020 ◽  
pp. 67-75
Author(s):  
K. V. Diadiun
Keyword(s):  
Mass Balance ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Tool Material ◽  
Automated System ◽  
Effective Control ◽  
Ion Plasma ◽  
Physical Deposition ◽  
Plasma Coatings ◽  
Metal Cutting Tool

Providing an increase in the working capacity of a metal-cutting tool, it is possible to significantly increase the productivity of mechanized labor, thereby reducing the cost of purchasing a new tool and saving on other accompanying technological components. During the operation of the cutting tool, the main load is transferred to its working part, this, as a rule, leads to partial wear or complete destruction of the planes and cutting edges. There are a number of technologies for processing working surfaces, which provides them with additional strengthening, the most effective of which is the method of applying special coatings to the surface of the cutting tool. Taking into account the specifics of the processes of formation of coatings, they can be divided into three main groups [1]. The first group includes methods in which the formation of coatings is carried out mainly due to diffusion reactions between saturating elements and structures of the instrumental material. The second group includes methods of forming coatings by a complex mechanism. The third group includes methods of forming coatings due to chemical and plasma-chemical reactions of particle flux simultaneously in volumes of space immediately adjacent to the saturable surfaces of the instrumental base. One such technology is the CIB (condensation and ion bombardment) method, which is a physical deposition of coatings. The most characteristic feature of coatings produced by this method is the absence of a transition zone between the coating and the tool material. This makes it possible to obtain a complex of properties on the working surfaces of the tool without deteriorating its original properties. The article is devoted to the issues of increasing the efficiency of ion-plasma technologies through the development and implementation of an automated system for analyzing and controlling the mass balance of reagent gases under conditions of several gases supply. Thus, the improvement of the technology of coating the working surfaces of the cutting tool, namely, the effective control of the process of applying ion-plasma coatings with the introduction of an automated system for analyzing and controlling the mass balance of reagent gases under conditions of supplying several gases is an urgent task.

scholarly journals The influence of hydrojet surface processing on the adhesive strength of wear-resistant coatings deposited on a metal-cutting tool of oxynitride ceramics

2018 ◽  
Vol 224 ◽  
pp. 01066
Author(s):  
Anton Seleznev ◽  
Anton Smirnov ◽  
Pavel Peretyagin
Keyword(s):  
Metal Cutting ◽  
Cutting Tool ◽  
Surface Defects ◽  
New Approach ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Cutting Ceramics ◽  
Nitride Ceramics ◽  
Cutting Inserts ◽  
Metal Cutting Tool

The work represents a new approach of preliminary surface treatment of replaceable polyhedral cutting ceramics inserts for significant increase of adhesion strength with deposited wear-resistant nitride ceramics. By this method the hydrojet treatment was used to repair surface defects occurring during manufacturing process of any required geometry of cutting inserts.

scholarly journals Construction of a specialized control system for brush machine and rounding the cutting edges of a metal cutting tool

2019 ◽  
Vol 298 ◽  
pp. 00064
Author(s):  
Petr Nikishechkin ◽  
Nikita Grigoriev ◽  
Nadezhda Chervonnova
Keyword(s):  
Control System ◽  
Metal Cutting ◽  
Structural Model ◽  
Cutting Tool ◽  
Wear Resistant ◽  
Wear Resistant Coatings ◽  
Machine Control ◽  
Metal Cutting Tool

The basic aspects of preparing a cutting tool for applying wear-resistant coatings to it, in particular, the use of brush technology to round its cutting edges, are investigated. A structural model for constructing a specialized brush machine control system has been developed and the basic aspects of its development have been determined.

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