Machines. Technologies. Materials.
Vol. 11 (2017), Issue 4

Table of Contents

  • MACHINES

    • FUTURE OF MACHINE-TOOL BUILDING — CORE OF ENGINEERING TECHNOLOGY

      pg(s) 148-154

      This article presents the results of scientific research performed by scientists at NTUU Igor Sikorsky Kyiv Polytechnic Institute in the creation and genetic forecasting of the development of a new generation of machine tools and associated mechanisms using the latest advances incorporated into an interdisciplinary intellectual field and based on a unified structured and systematic approach. It is suggested that the revival of the domestic machine-tool building can be done by virtue of an innovation breakthrough and implementation of the "Overdo without catching up!" strategic goal.

    • EULER BERNOULLI THEORY FOR A 3-DIMENSIONAL, VARIABLE-CURVETURE BEAM

      pg(s) 155-156

      The linear theory including the effects of bending-torsion coupling and rotatory inertia is used to derive the equations of motion for a space beam with variable curvature. The governing differential equations of motion are derived based on Euler-Bernoulli beam theory via Hamilton’s principle. The full, coupled system of governing partial differential equations has a total order of 12.

    • INFLUENCE OF THE SOIL PARTICLES ON THE WEAR OF PLOUGHSHARES DURING PLOUGHING

      pg(s) 157-160

      Researchs of the influence of the soil particles were perfomed on the powder loamy soil to powder clay texture. Standard and welded ploughshares were tested. The standard ploughshares are made of steel 50Mn7. The welded ploughshares are made by applying C-Cr-

      Co-Ni-Si additional material on the steel 50Mn7. The ploughshares are tested on the plough roller machine. Researches were perfomed in periods of 120, 240 and 360 hours of ploughing, or 60, 120 and 180 work hours of each ploughshare. After 180 hours of work at least average reduction of the ploughshares lenght was at welded ploughshares and it amounted to 8,27 % of the initial length. At the same time reduced the average length of the top of the ploughshares with standard ploughshares amounted to 19,65 % of the initial length. It was concluded that the application of welded ploughshares can contribute to increased of the productivity.

    • EXPERIMENTAL STUDY TO THE MACHINE FOR DRESSING OF WATER HOLDING MATERIALS INTO THE SOIL

      pg(s) 161-164

      We examined a machine for depositing the water storage materials layer by layer while in subsoil soil. As a result of this activity, improve physical and chemical properties of the soil, and yields have tended to increase sustainable. The article justified basic technological parameters of the machine to achieve the best results. The inclusion of such a machine technology for growing crops tasked along with higher yields reduce the negative impact of the processes that lead to soil degradation.

  • TECHNOLOGIES

    • OPTIMIZATION OF GEOMETRIC PARAMETERS OF HARD METAL MICRO DRILS TO INCREASE TOOL LIFE AND PERFORMANCE OF DRILLING PACKAGE OF PRINTED CIRCUIT BOARDS, DETAILS AND THE UNITS OF MECHATRONIC SYSTEM

      pg(s) 165-170

      In the presented work investigated the changes of power characteristics of deep drilling package of printed circuit board’s hard metal micro drills depending on the drilling depth, cutting data and geometry of the drill. In particular studied the nature of changes in axial efforts and torque depending on the drilling depth drill with different inclinations of the spiral grooves using specially designed highly sensitive devices, enabling direct measurement method. Based on the analysis of the results of the study, changes in the geometry of existing standard drills. Proposed new construction of micro drills vary-angle spiral grooves in such a way that the angle is the maximum value at the top of the drill and uniformly decreases towards the end of the working parts. The drills are manufactured with different inclinations of the spiral grooves. Based on the experiments of them chosen more for its near standing power rates to the standard drill bit and its comparative test with a standard drill bit, bringing them up to the breakage, thanks to which the proven advantages of drills new design. Taking into account the results of the experiments proposed drill elongated structures to improve performance by increasing the processing drilling depth and accordingly the number of plates in the package of printed circuit boards.

    • METHOD OF PREPARATION OF BLEND FOR ALUMINIUM MATRIX COMPOSITES BY HIGH VOLTAGE ELECTRIC DISCHARGE

      pg(s) 171-173

      Changes of dispersity, form factor and phase composition of powder mixtures of 75% Ti + 25% Al, 50% Ti + 50% Al, and 25% Ti + 75% Al mass compositions after treatment by high voltage electric discharge in kerosene are experimentally studied. Regularities of their dispersion and synthesis of TiC, AlTi3, AlTi, Al2Ti, Al3Ti, double carbide Ti3AlC, МАХ-phases Ti3AlC2 and Ti2AlC, Lonsdaleite are found.

    • METHOD FOR TECHNOLOGY PROCESS CONTROL OF ALIGNMENT TO

      pg(s) 174-177

      Processing of thin-walled parts with large dimensions in conditions of wide range production poses a number of technological problems. One of the most important among them is the provision of alignment on both sides of the hole who passing through the opposite walls of the part. Is essential the alignment of the spindles while processing of the hole , if used for this purpose machining center with two horizontal spindles . In the publication is presented research about possibilities to solve the problem by controlling of spindles alignment. For this purpose are carried out contact coordinate measurements of the hole in one spindle using 3D touch probe which is fixed in the other spindle.

    • INFLUENCE OF TEMPERATURE ON DIELECTRIC BREAKDOWN OF WORKING FLUID VAPOR IN HEAT PIPE

      pg(s) 178-180

      The paper deal with heat pipe technology which is often used in electronic cooling from small voltage microchips to the high voltage electric elements. In case of cooling the high voltage electric elements have to be evaporator part and condenser part of heat pipe a separated by electrical nonconductive material, because the heat pipes are most often made of metallic materials, and thus, are electrically conductive. As a working fluids in this applications are used dielectric fluids such as fluorinert liquids. But there is still risk of the dielectric breakdown between evaporator and condenser of heat pipe. The task of the experiment is to find how the ambient temperature effect on dielectric breakdown of vapour phase of working fluid in heat pipe. In experiment was investigated dielectric breakdown between copper pipes inserted in to glass heat pipe in distance of 70 and 65 mm and temperature range -10 to -40°C. This distance simulate electric insulator distance of heat pipe used for real application of high voltage electric element cooling. For this experiment was used glass heat pipe with working fluid Fluorinert FC 72. The choice of this fluid is mainly due its excellent dielectric properties and unique combination of the thermodynamic and others properties, which makes the Fluorinert FC – 72 ideal fluid for electronic cooling used in many electronic applications.

    • FAILURE ANALYSIS OF RUPTURED PIPE IN BOILER OF THERMO POWER PLANT

      pg(s) 183-185

      Pipe from the boiler of thermo power plant with diameter φ45was ruptured in exploitation conditions. In order to determine the reasons for this accident, very complex investigations of the pipe were performed.

      As first chemical composition was determined. Ovality and visual inspection of pipe were performed. Mechanical testing include tensile test at ambient and increased temperature of 350 0C. Thickness measurement of the wall pipe was made too. As technological testing flattening test of pipe segments was done. Metallographic investigations consist of determination of non-metallic inclusions, analyse of microstructure and grain size determination. Performed investigations didn’t indicate to defects in material and its processing. So, it can be concluded that working conditions in the boiler mainly overheating temperature caused damage of pipe.

    • ESTIMATION OF CUTTING FORCES IN HIGH PRESSURE JET ASSISTED TURNING USING PSO AND SA BASED APPROACH

      pg(s) 186-189

      Modelling and prediction of cutting forces in metal cutting is very important, due to their significant impacts on quality of machined surface, tool wear, self-excited vibrations, etc. However, accurate modelling of the cutting forces in high pressure jet assisted machining is not a simply task due to complex relations between many highly interlinked variables of cutting process influencing these forces. The objective of this study is to utilize two artificial intelligence methods, namely particle swarm optimization (PSO) and simulated annealing (SA), for prediction of the cutting forces components in high pressure jet assisted turning of carbon steel Ck45E. A study of effect of various process parameters including feed, cutting speed and depth of cut on the cutting forces was carried out. The results obtained from the PSO and SA based models were compared with experimental results for their performance. The analysis reveals that developed models are able to make accurate prediction of cutting forces by utilizing small sized training and testing datasets.

    • REVERSIBILITY IN AN INNOVATIVE DUAL MEMBRANE FUEL CELL DESIGN

      pg(s) 190-193

      A promising direction in the development of solid oxide fuel cells (SOFCs) is the reversible approach in which the device operates as fuel cell, producing electricity and heat, and as electrolyzer producing the hydrogen fuel. Reversibility strongly increases the device efficiency. It is very convenient for coupling with Renewable Energy Sources and for off grid applications. Although being very important, this direction of SOFC development still needs serious research efforts for the increase of durability, performances and efficiency and decrease of the switching time. A definitive breakthrough is the separation of the water production/consumption from the two electrodes. This work presents systematic studies on a new design of SOFC with a separate compartment for water formation in fuel cell mode and water injection in electrolyzer mode, named monolithic dual membrane fuel cell. It is based on the discovered property of some proton conducting ceramics to behave as mixed ionic conductors. The first tests of laboratory cells show promising performance with excellent reversibility which opens a pathway for further developments on higher technology readiness level.

    • Computer aided design (CAD) tools for analysis and design of integrated circuits

      pg(s) 194-197

      The design of electronic integrated circuits (ICs) can be achieved at many different levels from the most detailed layout to the most abstract architectures. This survey presents an overview of recent advances in CAD tools for analog and mixed-signal ICs. Due to the increasing levels of integration available in silicon technology and the growing requirement for digital systems to communicate with the continuous-valued external world, there is a growing need for CAD tools that increase the design productivity and improve the quality of analog ICs. In today’s market, there are plenty of CAD tools, however, most of them are expensive and require high performance platforms. Selecting an appropriate CAD tool for academic use is considered as one of the key challenges in teaching Microelectronics design. In this paper, number of open-source and freeware CAD tools are presented and evaluated. Based on the objectives of the user, this paper furnishes guidelines that help in selecting the most appropriate open-source and freeware CAD tool for teaching. The paper describes the motivation and evolution of these tools and outlines progress on the various design problems involved: simulation and modeling, synthesis and optimization, layout generation and tests.

  • MATERIALS

    • DIMENSION CHANGES OF IRON POWDER MATERIALS ALLOY WITH PHOSPHORUS DEPENDING ON THE PROCESS PARAMETERS DURING SINTERING

      pg(s) 198-202

      As a result of sintering the powder workpieces large part of the separated free energy leads to higher density of sintered body. This in turn is accompanied by a change in linear dimensions of workpieces. These linear changes in addition to the alloying elements in iron matrices largely depend on the technological parameters of the sintering process – temperature, duration, protective atmosphere and others. This study monitored the impact of the type of protective atmosphere and duration of sintering on the size change of powder workpieces of iron powder ASC 100.29 alloyed 0,15 ÷ 0,60% P. Sintering is conducted at 1150ºC a duration of 15 ÷ 90min in two protective environments – endothermic gas and dissociated ammonia. Presented are graphical relationships of the relative change in the diametric dimensions of the workpieces in dependence on the concentration of phosphorus in them, the type of the protective atmosphere and the duration of sintering.

    • GEOMETRY AND SURFACE ROUGHNESS OF POLYMERIC SAMPLES PRODUCED BY STEREOLITHOGRAPHY

      pg(s) 203-205

      The purpose of the present paper is to evaluate the geometric accuracy and surface roughness of polymeric samples manufactured by Digital Light Projection (DLP) Stereolithography. The standard cubic samples with dimensions 5 mm х 5 mm х 5 mm were printed of two polymers: NextDent C+B (white-yellowish color A3.5, VITA shade guide) and NextDent Cast (dark-red color), in two ways of placement to the base – horizontally and inclined at 45о. The samples were printed with two different layer’s thickness – 35 μm and 50μm. It was established that the samples of both polymers, manufactured in horizontal position with the lower layer’s thickness (35μm) possess highest dimensional accuracy and lowest interval of deviation. The most accurate are the dimesons parallel to the basis, while these, parallel or inclined to the print direction, have the highest deviations. The interval of the deviations of the dimensions of samples, manufactured inclined at 45o, is nearly 2-3 times higher, as the interval of the samples, made of NextDent Cast, is more than 50% higher than that of NextDent C+B. The horizontally printed samples have 1.5-2 times lower surface roughness compared to the samples, printed inclined at 45o. The surface roughness of the samples, made of NextDent Cast, is 30-50% higher than that of NextDent C+B independently of the layer’s thickness. The increase of the thickness from 35 μm to 50μm leads to 1.5-2 times higher surface roughness in the two samples’ positions. The optical properties of both polymers in the research strongly influence the geometric characteristics, dimensional accuracy and surface roughness of the objects, manufactured by DLP stereolithography.