COMBINED TECHNOLOGIES FOR MANUFACTURING PARTS IN SOLID ELECTROLYTES

Рассмотрены вопросы изготовления открытых и полуоткрытых полостей в труднообрабатываемых деталях путем использования твердого электролита, наносимого на заготовку перед установкой удаляемой вставки. Показаны особенности протекания процесса анодного растворения припуска при статическом состоянии рабочей среды. Такие исследования выполнены впервые. Разработаны и проверены на практике изготовления типовых деталей режимы обработки для реализации процесса. Показано, что твердые электролиты имеют перспективы для дальнейшего использования при проектировании технологических процессов изготовления сложнопрофильных изделий из металлических труднообрабатываемых материалов, в том числе внедряемых на создаваемых образцах ракетно-космической техники. Они расширяют технологические возможности комбинированных методов, в которых одним из воздействующих факторов является электрическое и электромагнитное поле с высокой концентрацией мощности в импульсе. Впервые достигнута возможность разделять сборочные единицы путем образования зазора между сопрягаемыми деталями без доступа в зону обработки жидкой рабочей среды, определяющей возможность локального съема припуска в месте сопряжения и удаления слоя материала, достаточного для разборки узлов. Заложены основы использования для нанесения твердого электролита аддитивных технологий путем наращивания равномерных слоев перед сборкой изделия. Предлагаемая технология перспективна для изготовления сборных конструкций с ограниченным доступом инструмента в зону выполнения операции. Кроме того, новая технология может успешно применяться в процессе ремонта машин We considered the issues of manufacturing open and semi-open cavities in difficult-to-machine parts by using solid electrolyte applied to the workpiece before installing the removable insert. We show the features of the process of anodic dissolution of the allowance at a static state of the working medium. Such studies have been performed for the first time. We developed and tested in practice the processing modes for the implementation of the process for the manufacture of standard parts. We show that solid electrolytes have prospects for further use in the design of technological processes for the manufacture of complex-profile products from metal hard-to-machine materials, including those introduced on the created samples of rocket and space technology. They expand the technological capabilities of combined methods, in which one of the influencing factors is an electric and electromagnetic field with a high concentration of power in a pulse. For the first time, the ability to separate assembly units by forming a gap between mating parts without access to the processing zone of a liquid working medium has been achieved, which determines the possibility of local removal of the allowance at the mating point and removal of a layer of material sufficient for disassembling the units. We laid the foundations for the use of additive technologies for applying solid electrolyte by building up uniform layers before assembling the product. The proposed technology is promising for the manufacture of prefabricated structures with limited tool access to the operation area. In addition, the new technology can be successfully applied in the process of car repair

METHOD FOR CALCULATING CUTTING FORCES BY MODELING CAD WITH A SYSTEM OF GEOMETRIC CUTTING PARAMETERS WITH RADIAL MILLS

The accuracy of processing surfaces of a complex profile largely depends on the selected processing strategy, which will allow creating the same, within certain limits, power characteristics of the shaping process at the intervals of the programmed tool path. In this case, it becomes possible to include tuning modules in programs for CNC machines that form vector values of corrections in certain areas, as reactors for elastic deformations of the cutting process. Therefore, it is especially important to know the modulus and direction of the resulting cutting force vector, which does not necessarily coincide with the feed direction. The purpose of this work is to build a method for calculating cutting forces by modeling the geometric parameters of a cut with a CAD system, a cutter with a nonlinear generatrix. Solid modeling of the process is based on the Boolean operations of "intersection" and "subtraction" of 3D objects: the teeth of a radius cutter with a helical cutting edge and a workpiece "moving" at a feed rate. The tool for the implementation of this method is a software module created on the basis of API functions, the input data for which are: a 3D tool and a workpiece, the equation of the trajectory of its movement and the parameters of the infeed movement. Targeting API properties, the application makes it possible to simulate various trajectories, helical or trochoidal, when machining complex surfaces. In the future, it is possible to take into account the plastic deformation processes in the chip formation zone in the model by connecting external modules. In the course of the conducted research on milling with radial end mills with a helical cutting edge, when two or more teeth are within the arc of contact, it was determined by 3D modeling how much thickness and width the layer cuts off each of the teeth during the feed per revolution. Consequently, in the process of shaping, normal and tangential cutting forces, which are different in direction and modulus, are present as a function of the angle of rotation of the cutter. Therefore, the concept of "circumferential force on the cutter", accepted in the theory of cutting, as a certain constant component of the process, can introduce an error when considering the causes of the excitation mechanism of vibrations of different nature that arise in the processing zone.

Two-stage magnetic-elasto-pulse stamping of thin sheet parts

The article substantiates the use of preliminary static loading and subsequent forging force when stamping thin sheet parts of complex shape with an elastic punch. The static load provides a relative deformation of the order of 20– 30% in the processing zone, which guarantees the stability of the position of the workpiece during subsequent pulsed loading. This technique is very important in the manufacture of asymmetric parts with a thickness of 0.01 – 0.3 mm. As a result, the accuracy of the products obtained corresponds to the 7th grade.The article provides a schematic diagram and a description of the proposed design of a double-action press, and analyzes the cyclogram of the device.It is recommended to carry out a static load with an electric drive, a pulsed one with a magnetic hammer, which is connected to a generator of impulse currents with a capacitive storage with an energy capacity of up to 40 kJ with a natural discharge frequency of the current of 20 kHz.

FLOW OF WORKING MEDIA THROUGH THE CHANNELS IN THE BODY OF THE ELECTRODE-TOOL

Рассмотрен механизм течения жидких и газожидкостных рабочих сред через профильный инструмент для комбинированных методов обработки. Приведены типовые детали, для которых применимы электроды-инструменты с регулируемой подачей рабочей среды в зону обработки, обеспечивающей массовынос продуктов обработки из межэлектродного зазора. За счет применения аддитивных технологий решена проблема изготовления инструмента с внутренними каналами расчетного переменного сечения, обеспечивающими стабильную подачу жидкой (газожидкостной) среды и массовынос продуктов обработки. Предложены новые (на уровне изобретений) способ и электрод-инструмент с управляемой подачей по внутренним каналам рабочей среды, параметры которой рассчитаны с учетом специфики чистовой электроабразивной обработки по схеме копирования профиля детали. Расчетные зависимости для описания механизма течения рабочих сред и методы их использования позволили проектировать электроды-инструменты с профильными каналами, обеспечивающими применение технологических режимов для чистовой обработки инструментом с регулируемой подачей сред и выполнением критерия массовыноса продуктов обработки. Приведенные результаты расчета параметров течения рабочих сред через каналы в инструменте позволили расширить область эффективного использования аддитивных технологий и создать новые (на уровне изобретений) инструменты для электроабразивной обработки по методу копирования и высокопроизводительного одновременного профилирования нескольких поверхностей. Доказана возможность использования энергетической модели для расчета потенциальной составляющей энергии от реализации мощности, затрачиваемой на подкачку рабочей среды, и кинетической энергии от вращения инструмента для получения в зоне обработки требуемой скорости течения жидких (газожидкостных) сред We considered the mechanism of flow of liquid and gas-liquid working media through a profile tool for combined processing methods. We present typical parts for which electrodes-tools are applicable with an adjustable supply of the working medium to the processing zone, which ensures the mass removal of processing products from the interelectrode gap. Through the use of additive technologies, we solved the problem of making a tool with internal channels of a calculated variable cross-section, providing a stable supply of a liquid (gas-liquid) medium and mass removal of processing products. We propose a new (at the level of inventions) method and electrode-tool with a controlled feed through the internal channels of the working medium, the parameters of which are calculated taking into account the specifics of finishing electro-abrasive machining according to the pattern of copying the profile of the part. Calculated dependencies for describing the mechanism of flow of working media and methods of their use made it possible to design electrodes-tools with profile channels that ensure the use of technological modes for finishing with a tool with controlled supply of media and fulfillment of the criterion of mass removal of processing products. The presented results of calculating the parameters of the flow of working media through channels in the tool made it possible to expand the area of effective use of additive technologies and create new (at the level of inventions) tools for electro-abrasive processing using the copying method and high-performance simultaneous profiling of several surfaces. The possibility of using the energy model for calculating the potential component of energy from the implementation of the power spent on pumping the working medium and the kinetic energy from the rotation of the tool has been proved to obtain the required flow rate of liquid (gas-liquid) media in the processing zone

Effect of Dynamic Bridging on Homogeneous Grain Movement in a Microwave Processing Zone

This article describes the influence of dynamic bridging in the unloading of a hopper at a processing plant on the grain flow homogeneity in a convective-microwave zone. In accordance with calculation methods for unloading hoppers, the parameters of the hopper unit and those of the outlet hole insuring that grain flows without static bridging formation is defined. It was found that moisture content fluctuations do not affect the process of grain transport. The equation for dynamic bridging rise depending on its position on the vertical axis of the unloading hopper has been deduced that enables the definition of the inhomogeneity of grain flow from its outlet hole. Calculations show that a certain inhomogeneity occurred between the right and the left parts of the unloading hopper in relation to its vertical axis in the course of grain discharging. This effect underlies the inhomogeneity of grain processing and reduction of its effectiveness in convective-microwave zones. An experimental model of unloading the hopper has been manufactured in order to perform investigational studies. The results of studies have completely confirmed the hypotheses. It has been found that dynamic bridge formation in unloading of the hopper results in the inhomogeneity of grain flow in convective-microwave zone.

Tool Wear Analysis during Ultrasonic Assisted Turning of Nimonic-90 under Dry and Wet Conditions

Nickel-based superalloys are widely used in the aerospace, automotive, marine and medical sectors, owing to their high mechanical strength and corrosion resistance. However, they exhibit poor machinability due to low thermal conductivity, high shear modulus, strain hardening, etc. Various modifications have been incorporated into existing machining techniques to address these issues. One such modification is the incorporation of ultrasonic assistance to turning operations. The assisted process is popularly known as ultrasonic assisted turning (UAT), and uses ultrasonic vibration to the processing zone to cut the material. The present article investigates the effect of ultrasonic vibration on coated carbide tool wear for machining Nimonic-90 under dry and wet conditions. UAT and conventional turning (CT) were performed at constant cutting speed, feed rate and depth of cut. The results show that the main wear mechanisms were abrasion, chipping, notch wear and adhesion of the built-up edge in both processes. However, by using a coolant, the formation of the built-up edge was reduced. CT and UAT under dry conditions showed an approximate reduction of 20% in the width of flank wear compared to CT and UAT under wet conditions. UAT showed approximate reductions of 6–20% in cutting force and 13–27% in feed force compared to the CT process. The chips formed during UAT were thinner, smoother and shorter than those formed during CT.

Use of Digital Twins for Mathematical Modeling of Ultrasonic Cutting of Titanium Blanks

The paper presents the results of numerical experimental studies of cutting titanium blanks using mathematical modeling programs, which make it possible to completely repeat technological processes in a computer (digital twin). The LS-DYNA product was used as a program to simulate the process of stock removal from titanium blank. It has been established that the use of this method adequately describes the cutting processes, including with the introduction of the energy of an ultrasonic field into the processing zone, can significantly reduce the duration of experimental research and evaluate the influence of the elements of the cutting mode and design parameters of the tool on the thermal power aspects of the formation of new surfaces of machine parts.

INFLUENCE OF THE OVERLAP COEFFICIENT ON THE CONTRAST IN LASER MARKING OF C110W STEEL

The laser marking process by melting samples of C110W carbon tool steel was studied. The experiments were performed with a fiber laser and a CuBr laser. A field of squares is marked in a raster method for different values of the overlap coefficient and power density. The contrast of the marking is determined on each marked square. From the obtained experimental data, graphs of the dependence of the contrast on the overlap coefficient for three power densities were drawn. The obtained results for the two lasers are compared and the influence of the wavelength is indirectly analysed. The working intervals of the overlap coefficient for the studied power densities for the two lasers at which the optimal contrast in the processing zone is obtained are determined.