SURFACE ROUGHNESS OF PARTS MADE TITANIUM ALLOYS MACHINED WITH FACE MILL OF ORIGINAL CONSTRUCTION

Importance of the use of titanic alloys is shown in many industries of engineer. Problems which arise at their processing are described that negatively affect process productivity and indicators of surface quality and etc. This is especially important when machining plane surfaces of parts by face milling. The surface roughness depends first of all on geometrical parameters and the shape of the cutting edge of the tool insert that contacts the processed surface. Therefore it was developed an original design of face mill with a stepped insert arrangement with a cylindrical front surface, and at the same time process productivity was improved. Expediency of use of the proposed design of a face mill it is proved by comparative experimental studies of influence of a form of a front surface of round inserts on roughness of the machined surface of parts from titanium alloy VT1-0. The comparison was made between the machining of the face mill with a cylindrical front insert surface and a standard face mill with round inserts (ISO 6462:2011). A non-composite second-order plan was received results of the study were obtained for the conditions of machining titanium alloy. The profile of the machined surface was investigated to evaluate the roughness Ra and it was determined that, with the maximum cutting modes, the face mill of the original design provided a lower roughness of the machined surface than a standard mill. The optimum cutting modes are determined by the criterion of the roughness of the machined surface of parts made of titanium alloy VT1-0 and the process productivity of face milling. The proposed face mill provides a 1.26 time increase in productivity compared to machining a standard face mill while obtaining minimal roughness

Generation of mechanical characteristics in workpiece subsurface layers through milling

The generation of mechanical characteristics in workpiece subsurface layers as a result of the cutting process has a predominant influence on the performance properties of machined parts. The effect of the end milling process on the mechanical characteristics of the machined subsurface layers was evaluated using nondestructive methods: instrumented nanoindentation and sclerometry (scratching). In this paper, the influence of one of the common processes of materials processing by cutting-the process of end tool milling-on the generation of mechanical characteristics of workpiece machined subsurface layers is studied. The effect of the end milling process on the character of mechanical property formation was evaluated through the coincidence of the cutting process energy characteristics with the mechanical characteristics of the machined subsurface layers. The total cutting power and cutting work in the tertiary cutting zone area were used as energy characteristics of the end milling process. The modes of the end milling process are considered as the main parameters affecting these energy characteristics. The mechanical characteristics of the workpiece machined subsurface layers were the microhardness of the subsurface layers and the total work of indenter penetration, determined by instrumental nanoindentation, and the maximum depth of indenter penetration, determined by sclerometry. Titanium alloy Ti10V2Fe3Al (Ti-1023) was used as the machining material. Based on the evaluation of the coincidence of the cutting process energy characteristics with the specified mechanical characteristics of the machined subsurface layers, the milling mode effect of the studied titanium alloy, in particular the cutter feed and cutting speed, on the generated mechanical characteristics was established.German Research Foundation (DFG

Interaction of mechanical characteristics in workpiece subsurface layers with drilling process energy characteristics

The performance properties of various types of parts are predominantly determined by the subsurface layer forming methods of these parts. In this regard, cutting processes, which are the final stage in the manufacturing process of these parts and, of course, their subsurface layers, play a critical role in the formation of the performance properties of these parts. Such cutting processes undoubtedly include the drilling process, the effect of which on the mechanical characteristics of the drill holes subsurface layers is evaluated in this study. This effect was evaluated by analyzing the coincidence of the energy characteristics of the short hole drilling process with the mechanical characteristics of the drilled holes’ subsurface layers. The energy characteristics of the short-hole drilling process were the total drilling power and the cutting work in the tertiary cutting zone, which is predominantly responsible for the generation of mechanical characteristics in the subsurface layers. As mechanical characteristics of the drill holes’ subsurface layers were used, the microhardness of machined surfaces and total indenter penetration work determined by the instrumented nanoindentation method, as well as maximal indenter penetration depth, were determined by the sclerometry method. Through an analysis of the coincidence between the energy characteristics of the drilling process and the mechanical characteristics of the subsurface layers, patterns of the effect of drilling process modes, drill feed, and cutting speed, which essentially determine these energy characteristics, on the studied mechanical characteristics have been established. At the same time, the increase in the energy characteristics of the short-hole drilling process leads to a decrease in the total indenter penetration work and the maximum indenter penetration depth simultaneously with an increase in the microhardness of the drilled holes’ subsurface layers.This study was funded by the German Research Foundation (DFG) in the project HE-1656/153-1, “Development of a Concept for Determining the Mechanical Properties of the Cutting Material in Machining”.German Research Foundation (DFG

Моделювання завантаженості безвершинних різальних кромок торцевої фрези із спірально-ступінчастим розташуванням ножів

A mathematical model of loading of the nose-free cutting edges of each insert of the face mill with a spiral-stepped cutting scheme was created. It was established that the size of the cut elements depends on the feed magnitude, the design parameters of the mill and the position of inserts on the contact arc. Variable factors of simulation included the feed magnitude, the clearance angle of the inserts and slope angles of the cutter assemblies. This made it possible to determine the chip thickness and width of cut, the depth of cut, the maximum value of the main cutting edge angle and the cut area at an arbitrary position of the face mill on the contact arc. Simulation in the SolidWorks Motion environment has confirmed reliability of mathematical modeling of loading of the cutting edges of the mill. The relative error in determination of the cut area was in the range from 1.8 % to 5.7 %.Calculation of the cut elements in the arbitrary position of the cutter insert on the contact arc was made in the Maple environment. Analysis of influence of the design parameters of the cutter and the magnitude of feed on the values of the cut elements was made. It has been established that an increase in feed caused a linear increase in the chip thickness and width of cut and the depth of cut for the inserts of all steps. Optimal values of the clearance angle of the mill inserts (16°) and slope of the cutting assemblies (6°) were determined for the milling depth of 3 mm. Recommendations on the choice of rational values of design parameters of the face mill for its effective operation at various depths of cut were given.Thus, there are grounds to assert the possibility of improving productivity of machining flat surfaces at a required quality due to the use of nose-free face mills with a spiral-stepped cutting scheme.Рассмотрена задача аналитического определения загруженности безвершинных режущих кромок торцевой фрезы со спирально-ступенчатым расположением ножей. Разработана математическая модель определения элементов среза в произвольном положении ножей фрезы на дуге контакта, достоверность которой подтверждена имитационным моделированием. Выявлены зависимости величины элементов среза от конструктивных параметров фрезы и подачиРозглянуто задачу аналітичного визначення завантаженості безвершинних різальних кромок торцевої фрези зі спірально-ступінчастим розташуванням ножів. Розроблено математичну модель визначення елементів зрізу в довільному положенні ножів фрези на дузі контакту, достовірність якої підтверджена імітаційним моделюванням. Виявлено залежності величини елементів зрізу від конструктивних параметрів фрези та подач

Моделювання завантаженості безвершинних різальних кромок торцевої фрези із спірально-ступінчастим розташуванням ножів

A mathematical model of loading of the nose-free cutting edges of each insert of the face mill with a spiral-stepped cutting scheme was created. It was established that the size of the cut elements depends on the feed magnitude, the design parameters of the mill and the position of inserts on the contact arc. Variable factors of simulation included the feed magnitude, the clearance angle of the inserts and slope angles of the cutter assemblies. This made it possible to determine the chip thickness and width of cut, the depth of cut, the maximum value of the main cutting edge angle and the cut area at an arbitrary position of the face mill on the contact arc. Simulation in the SolidWorks Motion environment has confirmed reliability of mathematical modeling of loading of the cutting edges of the mill. The relative error in determination of the cut area was in the range from 1.8 % to 5.7 %.Calculation of the cut elements in the arbitrary position of the cutter insert on the contact arc was made in the Maple environment. Analysis of influence of the design parameters of the cutter and the magnitude of feed on the values of the cut elements was made. It has been established that an increase in feed caused a linear increase in the chip thickness and width of cut and the depth of cut for the inserts of all steps. Optimal values of the clearance angle of the mill inserts (16°) and slope of the cutting assemblies (6°) were determined for the milling depth of 3 mm. Recommendations on the choice of rational values of design parameters of the face mill for its effective operation at various depths of cut were given.Thus, there are grounds to assert the possibility of improving productivity of machining flat surfaces at a required quality due to the use of nose-free face mills with a spiral-stepped cutting scheme.Рассмотрена задача аналитического определения загруженности безвершинных режущих кромок торцевой фрезы со спирально-ступенчатым расположением ножей. Разработана математическая модель определения элементов среза в произвольном положении ножей фрезы на дуге контакта, достоверность которой подтверждена имитационным моделированием. Выявлены зависимости величины элементов среза от конструктивных параметров фрезы и подачиРозглянуто задачу аналітичного визначення завантаженості безвершинних різальних кромок торцевої фрези зі спірально-ступінчастим розташуванням ножів. Розроблено математичну модель визначення елементів зрізу в довільному положенні ножів фрези на дузі контакту, достовірність якої підтверджена імітаційним моделюванням. Виявлено залежності величини елементів зрізу від конструктивних параметрів фрези та подач

Generation of Mechanical Characteristics in Workpiece Subsurface Layers through Milling

The generation of mechanical characteristics in workpiece subsurface layers as a result of the cutting process has a predominant influence on the performance properties of machined parts. The effect of the end milling process on the mechanical characteristics of the machined subsurface layers was evaluated using nondestructive methods: instrumented nanoindentation and sclerometry (scratching). In this paper, the influence of one of the common processes of materials processing by cutting—the process of end tool milling—on the generation of mechanical characteristics of workpiece machined subsurface layers is studied. The effect of the end milling process on the character of mechanical property formation was evaluated through the coincidence of the cutting process energy characteristics with the mechanical characteristics of the machined subsurface layers. The total cutting power and cutting work in the tertiary cutting zone area were used as energy characteristics of the end milling process. The modes of the end milling process are considered as the main parameters affecting these energy characteristics. The mechanical characteristics of the workpiece machined subsurface layers were the microhardness of the subsurface layers and the total work of indenter penetration, determined by instrumental nanoindentation, and the maximum depth of indenter penetration, determined by sclerometry. Titanium alloy Ti10V2Fe3Al (Ti-1023) was used as the machining material. Based on the evaluation of the coincidence of the cutting process energy characteristics with the specified mechanical characteristics of the machined subsurface layers, the milling mode effect of the studied titanium alloy, in particular the cutter feed and cutting speed, on the generated mechanical characteristics was established

Interaction of Mechanical Characteristics in Workpiece Subsurface Layers with Drilling Process Energy Characteristics

The performance properties of various types of parts are predominantly determined by the subsurface layer forming methods of these parts. In this regard, cutting processes, which are the final stage in the manufacturing process of these parts and, of course, their subsurface layers, play a critical role in the formation of the performance properties of these parts. Such cutting processes undoubtedly include the drilling process, the effect of which on the mechanical characteristics of the drill holes subsurface layers is evaluated in this study. This effect was evaluated by analyzing the coincidence of the energy characteristics of the short hole drilling process with the mechanical characteristics of the drilled holes’ subsurface layers. The energy characteristics of the short-hole drilling process were the total drilling power and the cutting work in the tertiary cutting zone, which is predominantly responsible for the generation of mechanical characteristics in the subsurface layers. As mechanical characteristics of the drill holes’ subsurface layers were used, the microhardness of machined surfaces and total indenter penetration work determined by the instrumented nanoindentation method, as well as maximal indenter penetration depth, were determined by the sclerometry method. Through an analysis of the coincidence between the energy characteristics of the drilling process and the mechanical characteristics of the subsurface layers, patterns of the effect of drilling process modes, drill feed, and cutting speed, which essentially determine these energy characteristics, on the studied mechanical characteristics have been established. At the same time, the increase in the energy characteristics of the short-hole drilling process leads to a decrease in the total indenter penetration work and the maximum indenter penetration depth simultaneously with an increase in the microhardness of the drilled holes’ subsurface layers

Комп’ютерне моделювання силового навантаження ножів торцевих фрез з циліндричною передньою поверхнею при різанні важкооброблюваних матеріалів

Вирішено задачу визначення силових характеристик процесу торцевого фрезерування шляхом комп’ютерного моделювання в середовищі DEFORM 3D. Досліджено вплив форми передньої поверхні круглих ножів торцевих фрез на площу контакту стружки з передньою поверхнею ножа, умови стружковідведення, динамічні силові навантаження як під час входу ножів у заготовку, так і після врізування. Підтверджується доцільність використання ножів із циліндричною передньою поверхнею в конструкції торцевих фрез, оскільки це зумовлює зменшення площі контакту стружки з передньою поверхнею ножа та покращення умов стружковідведення, в результаті чого забезпечується зменшення динамічного силового навантаження на ножі, як у момент врізування в заготовку, так і під час різання. Оскільки застосування генераторної схеми різання для торцевих фрез з циліндричною передньою поверхнею ножів накладає обмеження по глибині різання, то для умов оброблення з глибиною різання понад 1 мм запропоновано ступінчасту схему різання. За допомогою комп’ютерного моделювання процесу фрезерування плоских поверхонь деталей із загартованої високоміцної сталі й титанового сплаву визначаються силові характеристики для умов роботи ступінчастою торцевою фрезою з циліндричною передньою поверхнею ножів та стандартною фрезою з круглими пластинами. Для ступінчастої фрези підтверджується зменшення як ударних навантажень під час врізування ножа, так і середніх значень складової Pz сили різання порівняно зі стандартною фрезою для різних оброблюваних матеріалів. Зменшення крутного моменту від дії складової Pz створює передумови до зменшення ефективної потужності привода головного руху верстата, що може бути використане для оброблення зі збільшеними глибинами різання на верстатах малої потужності. Це може бути ще одним напрямом підвищення ефективності торцевого фрезерування важкооброблюваних матеріалів.The paper deals with the problem of determining the power characteristics of face milling process by computer modelling in DEFORM 3D environment. The influence of the rake face shape of round face mill inserts on the contact area of the chips with the inserts surface, the conditions of the chip removal, the dynamic power loads both during the inserts entry into the workpiece and after the cutting are investigated. The efficient use of inserts with cylindrical rake face in the face mills designs proved, as these results in the decrease of the chip contact area with the inserts surface and improvement of the chip removal conditions. It results in the reduction of the tool dynamic force load, both at the time of entrance to the workpiece, and during cutting. Using computer modelling of the milling process for parts flat surfaces made from hardened high-strength steel and titanium alloy, strength characteristics are determined for the operation conditions with the stepped face mill with cylindrical rake face of the inserts and the standard mill with round inserts. For the stepped face mill the reduction of both impact loads during the entrance the insert to the workpiece and the average values of the component Pz of the cutting force is confirmed in comparison with the standard mills for the various processed materials. The reduction of torque from component Pz action creates the premises for reducing the effective power of the main movement of the machine drive, what can be used for machining with increased depth of cutting on low power machines. This may be another way of increasing the efficiency of the face milling of difficult-to-cut material

Структурне удосконалення конструкцій торцевих фрез на основі системного підходу

Присвячено удосконаленню конструкцій торцевих фрез із круглими пластинами на основі системного підходу. Торцеві фрези з круглими пластинами знаходять широке застосування в машинобудуванні, оскільки вони є універсальними та використовуються як для складного торцевого фрезерування, так і для профільної обробки. Підвищення ефективності різання торцевими фрезами можливе через удосконалення їх конструкцій за такими напрямками: підвищення стійкості інструмента, точності та продуктивності обробки, покращення якості поверхневого шару обробленої поверхні деталі. Аналіз умов роботи ТФ здійснюється поелементно (корпус, хвостовик, ножі, їх розташування тощо). Ці складові розглядаються як одна система. Технологічна система (верстат, пристосування, заготовка, інструмент) представлена як надсистема, яка перебуває під впливом активних, проміжних діючих, реактивних та похідних чинників. Проведено декомпозицію на елементи (різальна, корпусна, базова і кріпильна частини) стандартної торцевої фрези з круглими пластинами та виконано їх системний аналіз щодо виникнення несприятливих умов різання. На основі цього розроблено схему напрямків структурного вдосконалення конструкцій торцевих фрез. Запропоновано технічні вирішення, спрямовані на суттєве підвищення стійкості інструменту, точності та продуктивності обробки, а також покращення якості обробленої поверхні деталі. Наведено основні пропозиції щодо вдосконалення конструкцій ТФ: виконання корпусу торової форми, ступінчасте розміщення ножів по спіралях Ферма, застосування циліндричної передньої поверхні ножів та виконання хвостовика з підвищеною жорсткістю з’єднання. В результаті структурного вдосконалення та синтезу варіантів розроблено концепції удосконалених конструкцій ТФ для різних умов обробки.The article is devoted to the designs improvement of face mills with round inserts on the basis of a systems approach. The increasing a cutting efficiency with face mills is provided by improving their designs in the following aspects: increasing the tool life, accuracy and productivity, improving the quality of the machined parts surface. Analysis of the operating conditions of the milling cutters is carried out element by element (body, shank, inserts and their location, etc.), these components are considered as one system. The technological system (machine, holder, workpiece, tool) is presented as a supersystem, which is under the influence of active, intermediate acting, reactive and derivative factors. The article decomposes into elements (cutting, body, base and fastening parts) of a standard face mill with round inserts and performs their system analysis relatively the occurrence of adverse cutting conditions. On the basis of this the scheme of structural improvement aspects of face mills designs is developed. As a result of structural improvement and variants synthesis, the authors propose concepts of face mills designs for different machining conditions