Cylindrical Part Research Articles

Research on end mill vibration in machining of VT9 titanium alloy

The reason for the failure of carbide end mills is the chipping of the cutting edges at the transition from the radius edges to the helix edges on the cylindrical part of the cutter. One of the reasons for the chipping of the cutting edges are the vibrations of the end mills which arise due to the intermittent cutting process and the variability of forces acting on the end mill. The principle of operation of a vibration measuring device is considered which allows vibration measurements to be carried out when milling with an end mill. The main measuring elements of the device are two eddy current sensors that allow measuring the vibration displacement of the milling cutter in two directions perpendicular and parallel to the movement of the longitudinal feed. The device has a compensation sensor that takes into account the influence of related factors, and a sensor for fixing the instantaneous rotation speed of the machine spindle. The milling cutter itself, fixed in a collet chuck, was used as an elastic element of the oscillating system. The data of measuring the amplitude of vibrations during milling of titanium alloy VT9 with a four-tooth and six-tooth end mill are presented. The study of vibrations of end mills included two stages. At the first stage, the influence of milling parameters and modes, as well as milling schemes (up and down milling) on the frequency and amplitude was investigated. At the second stage, measures were worked out to reduce the intensity of vibrations and increase the reliability and durability of the milling cutters. The research results showed lower amplitude values when working with a six-tooth cutter.

Fabrication of Conically Shaped CuCr1 Chrome Bronze Products by Wire-Feed Electron Beam Additive Manufacturing

The structure and properties of conically shaped products made of CuCr1 chrome bronze obtained by wire-feed electron beam additive technology have been investigated. The studies show that the organization of the structure in the samples fully corresponds to the peculiarities of the printing process and heat removal from the samples. The structure is represented by large grains elongated in the direction of heat removal. Chromium in the samples is mainly localized in the form of particles located between the dendrite arms. Near the substrate, intense mixing of the bronze with the substrate material (steel 321) is observed. The mechanical properties of the conical and cylindrical sample parts material are at a fairly close level. The samples are characterized by low values of yield strength, low values of tensile strength and high plasticity. Near the substrate, the mechanical properties of the specimens increase.

The Effect of Acceleration on the Separation Force in Constrained-Surface Stereolithography

Constrained-surface-based stereolithography has recently attracted much attention from both academic and industrial communities. Despite numerous experimental, numerical and theoretical efforts, the fundamental need to reduce the separation force between the newly cured part and constrained surface has not yet been completely solved. In this paper, we develop a fluid dynamics approach, proposed in our previous work, to theoretically model the separation force in 3D printing of a cylindrical part for flat and patterned windows. We demonstrate the possibility of separation force reduction with an accelerated movement of the printing platform. In particular, we investigate behaviors of transient parameter, its reduction rate, and separation force reduction with respect to elevation speed and time. The proposed approach involves deceleration and acceleration stages and allows to achieve the force reduction for the entire printing process. Finally, we provide implicit analytical solutions for time moments when switching between the stages can be done without noticeable increase of separation force and explicit expression for separation force in case of patterned window.

Фізичні особливості процесу багатоопераційного витягування циліндричних деталей із металевої сітки

In modern mechanical engineering, a method of single-operation extraction of cylindrical parts from a metal grid with a square mesh is known, which, in particular, has found application for the manufacture of microphone casings. Further improvement of the technology of extracting parts from a metal mesh in the direction of increasing the relative height of the stamped part is associated with the use of a multi-operation method of extraction. The study of this process will allow to significantly reduce the limit coefficient of extraction and thereby significantly increase the relative height of the part. Therefore, the work aimed at improving the technology of manufacturing parts from a metal mesh due to the use of a multi-operation method of extraction is an urgent scientific and practical task. The purpose of the study is to improve the technology of manufacturing cylindrical parts from a metal mesh by using a multi-operation method of drawing. The result of the work is the study of physical limitations that determine the limiting coefficient of multi-operational extraction of cylindrical parts from a metal mesh. The phenomenon of elasticity of the mesh wires was revealed, as a result of which the side wall of the part acquires a curved, close to conical shape. The physical similarity between the process of deformation of a single wire of a metal mesh during multi-operation drawing and the process of bending a flat workpiece is shown, which allows determining the technological effort of each drawing operation using formulas for calculating the bending force. In addition, two forms of instability of the process of multi-operational drawing of cylindrical parts from a metal grid with a square mesh were revealed, and a new method of drawing was proposed, which creates such stamping conditions, in which asymmetric deformation of the part (irreparable defect) is not observed, and separate additional means for cutting the edge of the stamped parts are not used.

DESIGNING THE STRUCTURE OF HINGED FASTENING OF THE MULTILAYER COMPOSITE BOARD TO A VEHICLE TRAILER BODY

Steel sides of dump tractor trailers used in the transportation of bulk and semi-liquid agricultural goods are subject to active abrasive wear and corrosion. The article proposes replacing the existing design of the sides, instead of steel sheets to use multilayer composite plates, which will increase the reliability and service life of the machine as a whole. (Research purpose) The research purpose is developing a design and methodology for calculating the hinge fastening of a composite side to the agricultural vehicle. (Materials and methods) The article analyses the existing metalcomposite compounds. When using multilayer sandwich-structured composites, all layers do not adhere to the metal base. We have developed a design of a pivotally movable side support of the trailer, which provides a tight connection due to the introduction of a metal steel element into the prepreg, consisting of a plate with studs and an axle welded to it. Additional tightening of the support due to threaded connections made it possible to connect a multilayer composite with metal plates. (Results and discussion). The article presents the equation of node loading to determine the maximum force acting on the fastener. The calculation of the most loaded part, the fastener, was carried out according to the permissible stresses of the cut of its cylindrical part. (Conclusions) The expediency of using power structures of vehicles of the agro-industrial complex exposed to abrasive wear and corrosion made of polymer composite materials is confirmed. A new design of a detachable swivel joint of a multilayer composite side with a metal frame was created.

Determination of the stress-deformed state of cylindrical parts at circular oscillation of a sectorial working tool

It is described the effect of the frequency of circular oscillations of a sectorial working tool on the stressstrain state of cylindrical parts. As a result of computer modeling, it was revealed that under the same loading conditions, the action of a working tool with different frequencies of circular oscillations creates different values of temporary and residual stresses. In the case of movement in one direction of the tool and the workpiece, the minimum value of stresses is formed, and with their oncoming movement, the value of the maximum stresses increases by 15...40 %. The resulting value of the residual stresses generally increases. With an increase in the frequency of circular oscillation of the working tool, the intensity of residual stresses increases by 1.2...2 times. The intensity of deformation changes in direct proportion to the value of the frequency of the circular oscillation and the depth of plastic deformation reaches 2.1...2.8 mm.

Numerical Simulation of Stagger Spinning of Cylindrical Part with Cross Inner Ribs

Numerical Simulation of Stagger Spinning of Cylindrical Part with Cross Inner Ribs

SIMULATION MODELLING IN THE TASKS OF DIGITAL ENGINEERING IN THE CREATION OF INFORMATION-MEASURING SYSTEMS

The object of this study is virtual measuring systems for shape deviation parameters. The article describes the designed virtual instrument for simulating the process of determining the parameters of the shape deviation of cylindrical shafts. To implement this task, a model for calculating the parameters of the deviation of the shape of the shafts is proposed, which takes into account the effect of random real diameters of the parts processed on metal cutting equipment on their geometric accuracy. The process of modelling the measurement of shaft shape deviation parameters is carried out in two stages. At the first stage, the movement of the plungers of the device to the surface of the shaft and the sound of the drive of the plungers are simulated. At the second stage, the parameters of the shape deviation of the cylindrical shafts are calculated. The shape of the cylindrical part depends on the random values of the actual diameters of the shaft in various intersections of the cylindrical part with planes. To obtain estimated values of shaft diameters in different cross-sections of the shaft by planes, an algorithm for calculating the current position of the profile point of the outer surface of the shaft has been developed. Because of the influence of physical cutting processes, the location of points on the surface of the shaft is random. Therefore, the position of the calculation point is determined by superimposing on the theoretical profile of the shaft a random variable, which is generated according to the law of equal probability. The method of processing the array of profile points coordinates to obtain numerical parameters of shaft shape deviation, such as taper, barrel, bow and ovality, is described.

EXPERIMENTAL TESTING OF PLUNGER RECOVERY MODES BY COMBINED PROCESSING

Stainless steel parts are widely used in milk processing equipment. The condition of these elements determines the operability of the equipment and the quality of the product. The most susceptible to wear are parts of the plunger type, the failure of which is by the loss of the cylindricity when changing geometric dimensions in longitudinal and cross sections. (Research purpose) The research purpose is developing a method for restoring cylindrical parts of the plunger type during combined processing; reducing the complexity of the restoration process and increasing the durability of the plunger (Materials and methods) Samples of 40Kh13 steel imitating the shape of a plunger with a diameter of 45 millimeters were studied. Three samples were produced with different pre-treatment: shot blasting, finishing turning and manual grinding. The study was as follow: initial measurement of the diameter in four sections at three levels; electric spark buildup, electromechanical processing and grinding before the preparing the working surface; measuring geometric parameters before and after each treatment; making slits for microstructural analysis, and measuring microhardness. (Results and discussion) As a result of the experiment and sample processing, there achieved an increase in diameter by 1.10 ± 0.08 millimeters when applying from 15 to 20 layers by the electric spark method with an electrode of the brand 308L-16. After deformation during electromechanical processing, the layer ranged from 0.36 ± 0.03 to 0.47± 0.07 millimeters, during grinding, the thickness of the final layer was from 0.04 ± 0.02 to 0.26± 0.02 millimeters. Measurements of the microhardness of the structural zones showed that the microhardness of the residual layer is 250-400 Vickers, the transition zone has a compacted structure and a hardness of over 550, and the core is 200-250. (Conclusions) Based on these data, the article proposes recommendations for the building of a compensation layer to restore the cylindrical working surface of the plunger type part.

Experimental investigation and optimization of turning process of EN8 steel using Taguchi L9 orthogonal array

Turning is a process of material removal from the external diameter of a rotating cylindrical work piece. It also referred as the process of machining that renders cylindrical parts. This article proposes an experimental investigation on turning process of EN8 steel as work piece at three distinct levels with various input process parameters like speed, cutting fluids and cutting depth with CNC lathe machine. Surface roughness is used as an output response parameter for determining the quality of turning operation. In addition, Taguchi approach, which is a powerful tool for optimizing the quality and output response of machining process with the consideration of parameter designing also employed for the optimization of process parameters for optimal machining operation. Experiments are conducted using L9 orthogonal array with three different levels of input process parameters and the analysis of test results is done using “smaller-the-better” standard for the signal-to-noise ratio (SNR). Finally, analysed, and confirmation test results obtained good enough surface finish.

Определение деформаций цилиндрических образцов оптическим способом с использованием метода цифровой корреляции изображений

A provision of location tolerances and their retention in the postoperative period is one of the main hard-hitting process tasks when producing long-length low-rigidity shaft-type parts. Mixed treatment – tensile straightening or thermal-power treatment is one of the technological methods intended to provide this group of geometrical indicators, including axle linearity. The efficiency improvement of this technology is impossible without knowing the features of the formation of plastic deformations distribution along the length of long-length blank parts. The paper considers the application of an optical method for controlling deformation on the surface using the method of digital image correlation at axial deformation of cylindrical parts. The work describes an experimental device for optic control of deformations when loading a specimen using digital cameras. The authors studied the influence of various modes of paint deposition to a sample (deposition rate, distance, deposition mode – continuous or pulsed) on the features of a produced speckle in the form of random distribution of mixed-size paint spots over the specimen surface; obtained histograms of the intensity distribution of various speckles. The authors carried out the experiments to identify deformations based on the technology of the local gradient digital image correlation method for the specimens of polymer tubes with different speckle types. The study identified the distribution of the deformation over the length of samples within the deformable area selected for analysis with the specified degree of smoothing provided by choice of correlation kernel size and the choice of its displacement step for fixing deformation processes with a precise error. The authors obtained distributions of axial deformations along the length of specimens and errors of deformations determination depending on a speckle nature. The study specifies necessary speckle parameters ensuring minimal error for long-length samples up to 200 mm in length and appropriate technology for paint depositing. It is a speckle with a wide range of spot sizes rarefied with their locations and the Gaussian filter image smoothing before the analysis.

Расчет энергофизических параметров плазменной печи с использованием цилиндрической модели дуги Меккера

The method of universal arc characteristics developed for calculating the electrical and thermal characteristics of the cylindrical part of the Mecker model column allows simple algebraic methods to calculate the characteristics of the arc column at a distance from the cathode and, thereby, to concretize the mathematical model of Mecker. The proven conservativeness of the arc as a result of the formation of a spatial layer with increased volumetric viscosity on the surface of the column allows, in accordance with the provisions of the boundary layer theory, to apply a boundary condition of the third kind to the surface of the cylindrical part of the arc column. The method of universal arc characteristics also helps to link the boundary value of the linear heat flux density on the surface of the cylindrical part of the column with the temperature profile of the column and, thereby, to specify the dependence of the electrical, geometric and thermal characteristics of the column plasma on the conditions of arc heat exchange in the working space of the installation with electric arc heating. The proposed method makes it possible, based only on the external voltage characteristics of the arc, to identify the Mecker heat exchange model and calculate by a simple algebraic method the structure and values of the heat fluxes generated by the arc during heat exchange with the plasma torch gas jet in the melting space of the plasma arc furnace. Examples of arc characteristics are given when working on different gases for different stages of melting — at the beginning of melting and during the melting of the charge.

Influence of process parameters on the forming results of large-sized cylindrical parts during counter-roller spinning

Influence of process parameters on the forming results of large-sized cylindrical parts during counter-roller spinning

Steam Generator Strength Computation for Nuclear Electric Power Plants of a Low Power

Today, the world oversees an explosive development of the nuclear power stations (NPS) of a low power. Most projects deal with pressurized water reactors and as a matter of fact with steam generators (SG). Ukraine has a well-developed engineering industry backbone that can be used for the production of the equipment required for the nuclear power plants of a low power. This scientific paper delves into the computations of the strength of elements used for the monotube steam generator with cylindrical coils that is the most presentable of all the projects in question in IAEA materials. Appropriate methods were developed to perform structural computations and steam generator strength computations. The mathematical model was developed that allows us to perform strength computations of the SG elements making use of the analytical method with reference to the Regulations and do simulations using the ANSYS software code. The specified elements include the body elements, in particular the cylindrical part, the flange, the bottom and the cover, including the heat carrier branch pipe and heat exchange tubes. The comparison of the data obtained by both methods showed their similarity and accordingly, the accuracy of the data that are indicative of the need for an increase in the wall thickness of the cylindrical part of the external branch pipe intended for the heat carrier. The body bottom strain for calculated dimensions exceeds the permissible value by 1.56 %. Since this value is 5 % lower than permissible values it is deemed that the strength condition is passed through. The simulation proved that the strength conditions are met for heat exchange tubes, for the body, the body cover, the body flange, the conical part of the external branch pipe intended for the heat carrier. Based on the analysis done, we would like to recommend performing strength computations using the normative method with the subsequent check out by the simulation using the computer code.

A PROPELLER BLADE MANUFACTURING BY HYBRID ADDITIVE MANUFACTURING SYSTEM

Hybrid Additive Manufacturing (Hybrid-AM) describes multi-operational or multi-functional additive manufacturing systems. In industry, the increasing tendency in applications of Hybrid-AM brings up the challenge of improving novel methods for the manufacturing of new or hybrid parts. Hybrid AM can produce fully functional assemblies without any assembly operation. In this study, the hybrid additive manufacturing system means that an object is to be designed partly made from prefabricated or off-the-shelf parts and added by the WAAM process. For this purpose, a prototype Hybrid-AM system using the pulsed TIG-Wire-Arc technique was designed and constructed. The constructed SMD system has three drivers on the x, y, and z-axes and an additional rotary driver (fourth axis). Using the Hybrid-AM machine the wire form material can be deposited on an existing primitive profile i.e., a rod, pipe, a profile, or any 3D surfaces with reducing production time. In this way, spiral-shaped features or twisted blade shapes can be added to cylindrical parts. In this study, a stainless- steel propeller blade was deposited on a pipe by using the developed prototype Hybrid AM machine. A non-planar toolpath was used to deposition the subsequent layers and the surface of the propeller blade was finished using 4-axis CNC machining.

Improving the technology for manufacturing hollow cylindrical parts for vehicles by refining technological estimation dependences

This paper shows that the technological preparation of production accounts for 20‒70 % of the total labor intensity of technical preparation. An important role belongs to the applied programs of finite-element modeling. However, such software packages often cannot be purchased by small-scale industrial enterprises for various reasons. Therefore, special empirical and analytical calculation models are used, which have proved to be quite effective in typical metal processing processes. Drawing a cylindrical hollow part was used as an example of the improved analytical dependence to calculate meridional tensile stresses. Existing analytical models of the process accounted for the bending moment through additional stresses. However, this approach only roughly described the deformation process. It was possible to refine the existing analytical dependences by introducing a term into the differential equilibrium equations that takes into consideration the bending moment that acts in the meridional direction when a workpiece passes the rounding on the matrix edge. Analysis of the obtained expression revealed that the bending of a workpiece gives rise to the stretching meridional stresses, which depend on the ratio of the squares of the thickness of the workpiece and the radius of the matrix rounding. The results of the estimation data from the numerical and theoretical models coincided for small values of the radius of the matrix rounding of 1‒2 mm, which confirms the adequacy of the analytical solution. In the numerical model, there is an extreme point where the tensile stresses have a minimum and, after it, begin to increase; this corresponds to the matrix rounding radius of 5 mm

Investigation of influencing factors of wear in a sandblasting machine by CFD-DEM coupling

In order to study the effect of particle characteristics and operating conditions (particle diameter, density, shear modulus, initial stacking height and inlet pressure) on the wear of the sandblasting machine, the gas-solid two-phase flow inside a sandblasting machine under different operating conditions was simulated by coupling the CFD and DEM methods in this work. Combining with the Archard wear model, the erosion was calculated and the erosion distributions were obtained in different sandblasting machine parts, including the top cover, inlet pipe, cylindrical part, conical part and lower pipe. The simulation results demonstrate that severe erosion in the sandblasting machine occurs at the lower pipe near the outlet, the conical part and the joints between different parts. The erosion volume order for different parts from high to low is: the lower pipe, conical part, cylindrical part, inlet pipe and top cover. The erosion volume of the sandblasting machine increases with the increase of particle diameter, density, shear modulus, stacking height and inlet pressure. Comparatively, the initial stacking height and inlet pressure have more influence on the erosion, while the particle density and shear modulus have less influence.

Justification of the Application of Resource-Saving Technology for the Restoration of Metal-Intensive Rear Semi-Axles of Trucks Using Hot Plastic Deformation

The article is devoted to the substantiation of technological foundations for the restoration of extremely worn-out, metal-consuming, and resource-consuming parts, in a method consisting of applying a compensating metal wear with subsequent plastic deformation. Currently, there are no technologies for their restoration in a repair facility that guarantee the resilience of the factory product. The proposed technological process of repair consists of butt welding onto the end of the spline semi-axle shank, compensating for the wear of the metal, the volume of which takes into account the losses resulting from the wear of the slots, as well as allowances for their machining. In the example of forging the axle shaft of a truck’s driving axle, the regularities of the plastic flow of metal during part deformation in the stamp are revealed. In the process of hot volumetric upsetting of long cylindrical parts with a variable diameter, it is important to know the possible directions of metal movements, as well as the energy-power characteristics of the process at various stages of forging. The evaluation criteria of the level of perfection of the technology were indicators of resource conservation and efficiency of the recovery route. The technological direction of the conducted research was analyzed, step by step, from the standpoint of saving repair materials and energy resources. The results of theoretical studies are crucial in the design of die tooling, for the manufacture of blanks, when restoring the rear axle shafts of trucks with pressure. Production tests carried out on the models, obtained as a result of mathematical processing of experimental data, confirmed the reliability of the experimental information. The introduction of the proposed set of repair equipment for the restoration of semi-axles will allow the formation of additional production in the region for the recycling of worn-out metal-intensive steel parts of agricultural machinery.

Numerical investigations of protective shells of NPP evergy units with pressurized water reactor (VVER)

Most of the energy units of nuclear power plants in Ukraine are at the stage of exhausting their design lifespan. Therefore, the issue of extending the lifespan of energy units of nuclear power plants (NPP) and, consequently, assessing the residual life of protective shells is very acute. State Enterprise "The State Research Institute of Building Constructions" developed universal computer models of NPP energy units from VVER-1000 type V-302 and V-338, taking into account all the design features of protective shells, load connections and the possibility of varying the level of pre-tensioning of ropes. The developed models made it possible to evaluate the operability of a localizing safety system - a hermetic enclosure system in all operating modes, including a combination of loads during a design basis accident and a maximum design earthquake. The purpose of this work is: on the basis of numerous studies of the load-bearing capacity of the protective shells of energy units in all operating modes, to develop a methodology for determining the rational tension of the ropes in rows, at which the forces in the ropes of all three rows under the action of emergency load coupling during normal operation plus design basis accident plus the maximum design earthquake (NO + DBA + MDE) is distributed most evenly and, as a result, the probability of breaking the ropes of the outer row during an accident is reduced.
 As a result of numerous studies of the load-bearing capacity of the protective shells of energy units in all modes of operation and the determination of the rational tension of the ropes in rows under the action of NO+DBA+MDE, the following has been established: minimum allowable tensile force of reinforcing ropes in the cylindrical part of the protective shell of the energy unit in the absence of two ropes; minimum allowable tensile force of reinforcing ropes in the cylindrical part of the protective shell of the energy unit in the absence of three ropes. The rational distribution of rope tension between the rows is determined, in which the efforts in the reinforcing ropes of all three rows under the action of NO+DBA+MDE are distributed most evenly and, as a result, the probability of breaking the ropes of the outer row in case of an accident is reduced.

Computer-Aided Design of Traditional Jigs and Fixtures

Conventional design of jigs and fixtures has become unsuitable given the requirements of modern technology and complexity and diversity in the production with the rapid update of products. Computer-aided design (CAD) of jigs and fixtures is an effective solution in this direction. The current paper focuses on a computer-aided design of the traditional jigs and fixtures and developed a system containing tailor-made software, created using the Visual Basic programming language and installed on it the viewer screen to show the part. The developed system has been built by connecting Visual Basic programming language to the SolidWorks software on which the part is drawn and saved as STEP AP-203 file format, and the system reads and extracts the data from the STEP AP-203 file. Heuristic rules of feature recognition are pre-prepared for checking the extracted geometric data and deciding which data shape will represent the machining feature; then, the system provides the optimum design of the traditional jigs and fixtures for a group of hollow cylindrical parts that contain a group of cross-holes on the cylinder body, whether perpendicular or offset from the cylinder’s axis, (inclined or inclined offset, or blind or through, by applying pre-prepared heuristic rules for the design of traditional jigs and fixtures.