ANALYSIS OF TECHNOLOGICAL POSSIBILITIES OF TWO-CHAMBER IMPULSE DEVICES FOR SHEET STAMPING

Проведен анализ технологических возможностей двухкамерных устройств для листовой штамповки с одной и двумя камерами сгорания. В устройствах с одной камерой сгорания штамповка детали происходит в холодном состоянии заготовки под действием на нее гибкой среды за счет кинетической энергии поршня, ускоряемого продуктами сгорания газообразной топливной смеси. В устройствах с двумя камерами сгорания процесс штамповки совершается с нагревом заготовки воздействием на нее горячего газа, образованного при сгорании в верхней камере предварительно сжатой топливной смеси. При этом сжатие смеси осуществляется за счет энергии продуктов сгорания, образованных в нижней камере сгорания. Доказано, что устройства с одной камерой сгорания целесообразно использовать для штамповки из пластичных сортов сталей деталей разнообразной формы толщиной до 4 мм и из пластичных цветных сплавов толщиной до 8 мм. Устройства с двумя камерами сгорания целесообразно использовать для штамповки деталей из малопластичных сортов алюминиевых, титановых сплавов и других труднодеформируемых сплавов. Двухкамерные устройства для листовой штамповки обладают широкими технологическими возможностями и могут быть эффективно использованы в мелкосерийных производствах для штамповки деталей различной формы We carried out the analysis of technological capabilities of two-chamber devices for sheet stamping with one and two combustion chambers. In devices with one combustion chamber, the stamping process is carried out in the cold state of the workpiece by the action of an elastic medium on it, using the kinetic energy of the piston accelerated by the combustion products of the gaseous fuel mixture. In devices with two combustion chambers, the stamping process is carried out with the heating of the workpiece by the action of the hot gas formed during combustion in the upper chamber of the pre-compressed fuel mixture. In this case, the mixture is compressed due to the energy of the combustion products formed in the lower chamber. We established that devices with one combustion chamber are expedient to be used for stamping parts of various shapes with a thickness of up to 4 mm and from plastic non-ferrous alloys with a thickness of up to 8 mm from ductile steels. Devices with two combustion chambers are advisable to be used for stamping parts from low-plastic grades of aluminum, titanium alloys and other hard-to-deform alloys. Two-chamber devices for sheet stamping have wide technological capabilities and can be effectively used in small-scale production for stamping parts of various shapes

RESEARCH OF ENERGY EFFICIENCY OF TWO-CHAMBER PULSE DEVICES FOR STAMPING

Одной из разновидностей устройств, осуществляющих импульсные методы обработки давлением, являются двухкамерные устройства для листовой штамповки, использующие в качестве энергоносителя газовоздушные топливные смеси. Подача сжатого воздуха в камеру сгорания в рассматриваемом двухкамерном устройстве для листовой штамповки осуществляется компрессором. Проведен анализ термодинамических процессов, протекающих в камере сгорания и рабочем цилиндре двухкамерного устройства для листовой штамповки. При этом установлено, что энергия, затрачиваемая на работу компрессора, составляет около 45% от энергии, выделяющейся в камере сгорания. Получена зависимость для определения термодинамического КПД двухкамерных устройств для листовой штамповки, величина его составляет около 0,25. Установлено, что энергоэффективность двухкамерных устройств не уступает энергоэффективности традиционного штамповочного оборудования, при этом затраты на энергоносители двухкамерных устройств ниже за счет использования дешевого энергоносителя. В двухкамерном штамповочном устройстве для листовой штамповки электрическая энергия, используемая на работу компрессора, составляет менее 1/3 общей потребляемой энергии устройства. Поэтому при прочих равных условиях расходы на энергоносители будут значительно меньше, чем в штамповочном оборудовании, работающем на электрическом токе One of the types of devices that carry out pulse methods of pressure treatment are two-chamber devices for sheet stamping, using gas-air fuel mixtures as an energy carrier. The supply of compressed air to the combustion chamber in the considered two-chamber device for sheet stamping is carried out by a compressor. We carried out the analysis of thermodynamic processes taking place in the combustion chamber and the working cylinder of a two-chamber device for sheet stamping. We found that the energy spent on the operation of the compressor is about 45% of the energy released in the combustion chamber. We obtained the dependence for determining the thermodynamic efficiency of two-chamber devices for sheet stamping; its value is about 0.25. We established that the energy efficiency of two-chamber devices is not inferior to the energy efficiency of traditional stamping equipment, while the energy costs of two-chamber devices are lower due to the use of a cheap energy carrier. In a two-chamber die-forging device for sheet metal stamping, the electrical energy used to operate the compressor is less than 1/3 of the total energy consumption of the device. Therefore, all other things being equal, the cost of energy carriers will be significantly less than in stamping equipment operating on electric current

Bending of sheets and profiles on a four-roll machine for rocket bodies, pipe and frame products. Part 7

The theory and calculation of the parameters of the strain-stress state at the stages of pre-bending, calibration, straightening, bending of a straightened section and bending of the subsequent sections, taking into account the hardening of the billet on a roller machine, is developed. Deformations, stresses and forces acting on the billet from the rolls were investigated by CAD/CAE-modeling. Criteria for the formation of cracks, low accuracy and excessive springback of the part after these stages of processing are determined. Recommendations for the elimination of these defects are given. Keywords: sheet stamping, billet, bending, roller machine, pre-bending, calibration, straightening, CAD/CAE modeling. [email protected]

INVESTIGATION OF METHODS OF HEATING WORKPIECES DURING HOT SHEET STAMPING

An overview of new theoretical studies in the field of methods of heating hot sheet stamping of extra-strong metal alloys and the formulation of research tasks is presented

Explosive Stamping Goals and Objectives Historical Transformation (to the 70th Anniversary of KhAI Scientific School)

The sequence and development the impulse stamping goals and production objectives are described. A new idea development from a primitive “field” technology to modern integrated technologies that allow obtaining unique quality indicators of manufactured parts is shown. The article covers the description of pulse technologies for sheet stamping by the blasting agents explosion and an underwater high-voltage discharge.

СТРУКТУРА ДОСЛІДЖЕННЯ ЕНЕРГОСИЛОВИХ ПАРАМЕТРІВ ПРОЦЕСІВ ЛИСТОВОГО ШТАМПУВАННЯ

One of the main tasks of theoretical research is to identify optimal conditions for deformation. The greatest interest for practice is determination of main technological parameters of shaping process and their connection with external factors. The solution to the problem is a very important and crucial stage of theoretical investigation. It is inextricably linked with choosing theoretical method of analysis and design scheme, which most fully meets requirements and particular case of shaping conditions. The article discusses structure of complex theoretical and experimental investigations sheet drawing energy-power parameters of technological processes. Mathematical model has been proposed based on the constructed structural-logical scheme for effective forecasting of energy-power parameters, which determines methods and sequence of theoretical and experimental researches. It reflects correlation between functional characteristics of machining and technological parameters of the sheet stamping-drawing. The character of shaping has been determined, which is provided by plastic deformations in the processes of metal working by pressure. It has been determined that loss workpiece stability or its destruction impose restrictions on allowable deformation degree, which is defined in the deformation zone by stress field. Method for calculating processes of plastic deformation metals is proposed which it is using to theoretical investigation energy-power parameters of technological processes of sheet stamping. It is based on closed system equations of continuum mechanics. The form of particles velocity functional dependence of plastically deformable material on coordinates in stamping-drawing process of sheet has been determined. Expressions are analyzed which make it possible to make the spatial picture distribution of deformation in metal during sheet stamping. This allows visualizing deformation mechanism and simplifying the analysis material deformed state. The relationship between velocity and energy dissipation function is shown at total work deformation is found, which makes it possible to determine force parameters of sheet stamping-drawing process. A functional relationship between the deformation power and the parameters of processing modes during sheet stamping has been investigated. Approaches to determining deformed material state are considered.

Bending of sheets and profiles on a four-roll machine for rocket bodies, tubular and frame products. Part 6

The theory and calculation of the parameters of the strain-stress state at the stages of pre-bending, calibration, straightening, bending of a straightened section and bending of the next section, taking into account the hardening of the workpiece on a roller machine, is developed. Deformations, stresses and forces acting on the workpiece from the rolls were investigated by CAD/CAE-modeling. Criteria for the formation of cracks, low accuracy and excessive springback of the workpiece after these stages of processing are determined. Recommendations for eliminating these defects are given. Keywords: sheet stamping, billet, bending, roller machine, pre-bending, calibration, straightening, CAD/CAEmodeling. [email protected]

Theoretical aspects of obtaining a helical surface from a thin strip during sheet stamping

В статье рассмотрены теоретические аспекты получения винтовой поверхности из тонкой полосы при листовой штамповке. Также предложена модель для расчета компонентов напряженно-деформированного состояния полосы и отдельных технологических параметров. Для удобства расчетов предполагается, что полоса имеет достаточную длину и угол закручивания по всей длине полосы одинаков. Несмотря на значительные упрощения геометрического характера, задача о кручении полосы остается сложной, вследствие двумерности напряженного состояния, геометрической и физической нелинейности процесса деформирования. Ее дальнейшее решение целесообразно основывать на методе конечных элементов, ориентируясь на применение ЭВМ. Для замыкания системы уравнений, описывающих поведение дискретной модели полосы на шаге нагружения, необходимо связать напряжения и малые приращения деформаций в середине каждого элемента. Для этого используем теорию пластического течения, пренебрегая упругими составляющими деформаций вследствие их малости по сравнению с большими пластическими деформациями. The article deals with the theoretical aspects of obtaining a helical surface from a thin strip during sheet stamping. A model is also proposed for calculating the components of the stress-strain state of the strip and individual technological parameters. For convenience of calculations, it is assumed that the strip has a sufficient length and the angle of twisting along the entire length of the strip is the same. Despite significant geometric simplifications, the problem of band torsion remains complex due to the two-dimensionality of the stress state, the geometric and physical nonlinearity of the deformation process. Its further solution should be based on the finite element method, focusing on the use of computers. To close the system of equations describing the behavior of the discrete band model at the loading step, it is necessary to relate the stresses and small increments of deformations in the middle of each element. To do this, we use the theory of plastic flow, neglecting the elastic components of deformations due to their smallness in comparison with large plastic deformations.

Study and analysis of stress-strain state of shearing operations of sheet stamping

The analysis results of the effect of the inter-tool gap and the material on the quality of the punching products are presented. The issues for determining of the rational values range of the inter-tool gap, taking into account the result of the shearing process simulation in the LS-DYNA system.

Research of stamping of unequal channel bars. Part 1. Comparison of technological capabilities of existing methods of channels manufacturing

By comparison of the technological capabilities of extrusion, sheet stamping, rolling, profile bending and pressing it is shown the advantage of extrusion processing in the manufacture of channels with elements of different thickness. Keywords: pressing, extrusion, channel. [email protected]