Vat Photopolymerization of Cemented Carbide Specimen

Numerous studies show that vat photopolymerization enables near-net-shape printing of ceramics and plastics with complex geometries. In this study, vat photopolymerization was investigated for cemented carbide specimens. Custom-developed photosensitive WC-12 Co (wt%) slurries were used for printing green bodies. The samples were examined for defects using quantitative microstructure analysis. A thermogravimetric analysis was performed to develop a debinding program for the green bodies. After sintering, the microstructure and surface roughness were evaluated. As mechanical parameters, Vickers hardness and Palmqvist fracture toughness were considered. A linear shrinkage of 26–27% was determined. The remaining porosity fraction was 9.0%. No free graphite formation, and almost no η-phase formation occurred. WC grain growth was observed. 76% of the WC grains measured were in the suitable size range for metal cutting tool applications. A hardness of 1157 HV10 and a Palmqvist fracture toughness of 12 MPam was achieved. The achieved microstructure exhibits a high porosity fraction and local cracks. As a result, vat photopolymerization can become an alternative forming method for cemented carbide components if the amount of residual porosity and defects can be reduced.

Combined Lubrication of Surface Texturing and Copper Covering for Broaching Tool

The broaching tool is an efficient and precisely heavy-loaded metal-cutting tool, widely used in the mass production of key components related to the aerospace and automobile industries. However, the heavy load, intense squeezing, and friction in the tool-chip contact area prevent the cutting fluid from entering the desired location. Consequently, insufficient lubrication gives rise to a high-temperature built-up edge, thereby lowering machining accuracy and efficiency. To reduce frictional force, three textures (i.e., micro-pit, stripe, mesh) are prepared on the rake face of broaching tool with laser processing technique. Afterward, textured grooves are covered with copper using the reciprocating rotational friction; this artifact enhances the system’s wettability and heat dissipation ability. Experiments approve that compared to the non-textured cutting teeth, the cutting force with the stripe-textured teeth is reduced by 7.6%. Nevertheless, the cutting force is decreased by 14.6% after covering the tool surface with copper. Obtained results indicate that the wettability of cutting fluid on the surface is improved. In addition, convex peaks on the tool surface are passivated during the reciprocating rotation of the copper bar.

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

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.

Study on the Influence of Silicone-Based Magnetorheological Elastomer on Tool Vibration During Turning of Hardened SS410 Steel

In metal cutting, tool vibration is a significant parameter, which results in high cutting force, increase in tool wear and poor surface quality of the finished product. To control tool vibration, an innovative and a robust damper was required. In this regard, a magnetorheological elastomer was fabricated, and the effect of parameters like the ratio of iron particles to elastomer; plunger shape and intensity of current were studied. Cutting experiments were conducted to arrive at an optimum set of parameters, which can suppress tool vibration during turning of hardened SS410 steel. From the experimental results, it was observed that the use of magnetorheological elastomer has reduced the tool vibration by 60% and also improved the cutting performance significantly.

EFFICIENCY OF APPLICATION OF THE COMBINED METAL CUTTING TOOL

Проблема и цель. Одним из элементов успешного функционирования организаций в современных условиях рынка является цель – повысить эффективность производственных процессов и конкурентоспособность выпускаемого продукта. При этом многие предприятии задумываются о применении новых инновационных технологий или методик организации производства, в частотности, внедрении концепции «бережливого производства». Методология. «Бережливое производство» в современном варианте – многогранная концепция, насчитывающая более 35 инструментов. Многие из инструментов решают вопрос по сокращению потерь времени на производстве. В качестве одного из вариантов для сокращения времени выполнения операций можно рекомендовать применение комбинированного инструмента. Результаты. Приведено сравнение комбинированного металлорежущего инструмента для нарезания метрической резьбы, М6 шаг1, совмещающего в себе операции по сверлению, нарезанию резьбы и зенкованию отверстий с классической технологией нарезания резьбы, включающей использование таких инструментов, как сверло, метчики (первый и второй номер, М6, шаг1) и обработку края отверстия зенкером. Сравнения проводили при нарезании метрической резьбы в стальной пластине и в профильной трубе. При сравнении оценивались такие показатели, как затраты времени, себестоимость операции и производительность. Заключение. По результатам проведенных сравнений выявилось преимущество комбинированного инструмента, позволившего за одну операцию произвести 3 действия, затратив при этом в среднем 1,5 минуты; та же операция, выполняемая 4-мя инструментами, потребовала более 6 минут. Технологическая себестоимость при использовании комбинированного инструмента была ниже в 1,5 раза, а производительность увеличилась в пять раз. Problem and purpose. One of the elements of the successful functioning of organizations in modern market conditions is the goal - to increase the efciency of production processes and the competitiveness of the product. At the same time, many enterprises are thinking about the use of new innovative technologies or methods of organizing production, in frequency the introduction of the concept of "lean production". Methodology. "Lean Manufacturing" in its modern version is a multifaceted concept with more than 35 tools. Many of the tools address the issue of reducing lost time in production. One of the options for reducing the time for performing operations can be recommended using a combined tool. Results. A comparison is given of a combined metal-cutting tool for cutting metric threads, M6 step1, which combines the operations of drilling, threading and countersinking holes with the classic threading technology, including the use of tools such as a drill, taps (frst and second number, M6, step1) and processing the edge of the hole with a countersink. Comparisons were made when cutting metric threads in a steel plate and in a profle pipe. The comparison evaluated metrics such as time required, cost of operation, and productivity. Conclusion. According to the results of the comparisons, the advantage of the combined tool was revealed, which made it possible to perform 3 actions in one operation while spending an average of 1.5 minutes (the same operation performed by 4 tools required more than 6 minutes), the technological cost when using the combined tool was 1.5 times lower, and the productivity increased fve times.

PROSPECTS FOR THE USE OF VIBRATION DURING CUTTING MATERIAL

Vibration is considered one of the effective ways to sharpen billets from difficult materials. The rational purpose of cutting modes with such a process allows you to increase the resistance of the metal-cutting tool, contributes to the creation of conditions to ensure constant crushing of chips. When cutting materials on the lathes of a turning group with the imposition of oscillations to the cutting tool, processes occur in the cutting zone, which differ from the processes arising from sharpening without oscillations. The article discusses the possibilities of using vibration oscillations when cutting materials. Currently, new materials that have high strength characteristics, viscosity and plasticity are widely used in mechanical engineering, with an increase in the processability: cutting force increases and efficient power spent on cutting; The quality of surface roughness is worsen; the resistance of the cutting tool is reduced; The amount of heat formed in the cutting zone increases and the character of its distribution on the surfaces of the workpiece and the tool changes; the process of forming chips, its shrinkage and type; The intensity of the process of formation of outflow and its form. In this regard, the question arises about the search for rational processing methods, in particular, mechanical processing with cutting on lathes. In this scientific work, the use of low-frequency oscillations is substantiated, which is the complex vibrational effect on the cutting process with the enforcement of solid chips, removal from the top of the cutter and preventing its formation, while ensuring the presence of a given roughness of the treated surface and an increase in the cutter resistance period. Research work in this direction is relevant and requires further research.

Implementation of a Group Cutting Scheme during Processing of Large-Module Gears with a Prefabricated Tool

Currently, when machining gears, the main problem arises - the resistance of a standard worm mill. In the current conditions of sanctions, import substitution and the launch of the State program for the development of its own metal cutting tool designs by tool companies, the creation of prefabricated structures can be considered a promising and effective solution, since this has been repeatedly confirmed by leading Russian researchers [1-8].

Predicting the Durability Period of a Metal Cutting Tool Based on a Neural Network

Рассматривается задача прогнозирования периода стойкости металлорежущего инструмента при заданных параметрах режима резания. Для решения поставленной задачи предлагается использовать нейросетевую модель. Предложено использовать в качестве структуры нейронной сети многослойный персептрон. Обучающей выборкой при обучении нейросетевой модели прогнозирования служат накопленные статистические данные системы «Инструментальный шкаф». Входными данными нейронной сети служат значения параметров режима резания (тип материала заготовки, значение глубины резания при технологической операции, значение подачи при технологической операции, значение скорости резания) и значения параметров конструкции металлорежущей пластины, указанных в маркировке пластины согласно ISO 1832-85. Программная реализация предложенной нейронной сети выполнена с использованием библиотеки машинного обучения «DeepLearning4J».При обучении нейронной сети формировалось 5 обучающих подвыборок, содержащих по 20 % от количества образцов в обучающей выборке. Для решения проблемы переобучения нейронной сети использовался метод перекрестной проверки. Использовалась обучающая выборка общим количеством 500 записей по множеству металлорежущего инструмента, состоящему из 10 пластин. Проведенные эксперименты показали работоспособность предложенного подхода. В работе представлены графики, показывающие зависимость прогнозируемого периода стойкости от одного из параметров режима резания.Цель работы заключается в повышении эффективности планирования закупок металлорежущего инструмента.