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An approach to increasing the efficiency of the diamond grinding of hard-working materials is shown. A well-founded choice of characteristics of the diamond-bearing layer of the tool can be made through analyzing the results of 3D modeling of the processes of formation and operation of the diamond-bearing layer and stresses upon it. Diamond wheels formed on porous ceramic binders are investigated and discussed.

The given paper is closely connected with the experimental and numerical modal analysis of the carbon composite plate damaged by cut. In relation to the tested carbon composite, modal analysis was performed by help of special measuring device Pulse 12. The mentioned device was supplied by company Brüel & Kjear and the experimental measurements were carried out using damaged and undamaged plate sample which were prepared from the mentioned material hereinbefore. The investigated and analyzed plates of carbon composite were made of six layers of carbon fibres and they were arranged under the angle 90º (it is like fabric material made off carbon fibres). The layers arranged in the given way were joined by epoxide resin MGS 285. The experimental measurement of eigenfrequencies of carbon composite plates was carried out using the undamaged and damaged sample with proportions 78 mm x 78 mm while ten measurements were performed for each one specified site of the sample. In relation to the damaged plate sample, there was cut in length of 20 mm in the centre border. The finite element method in the software system ADINA v.8.6.2 was used for numerical analysis of the eigenfrequencies.

Irradiation of polymeric materials is a modern method of modifying their final properties (for example, improvements in mechanical, thermal and chemical properties). The main used types of radiation to modify polymers include ionic and ionizing radiation. Due to its properties, ionization beta (electron) radiation is the most widely used. The interaction of ionizing radiation with polymeric materials manifests as radiation cross-linking, which is a result of recombination of migrating polymer radicals into the amorphous region. In this type of radiation, electrons are generated under high vacuum using a hot cathode. Electrons emitted from the cathode are then accelerated in the electrostatic field that arises between the cathode and the anode. The depth of penetration into the material rises with increasing energy of electrons. This study examines the influence of ionizing beta radiation on the flammability index and ignition temperature of thermoplastic materials.

In order to successfully acquire knowledge in area of machinery safety for engineering students it is necessary to adopt elementary principles associated with risk assessment. Identification of possible hazards is an important part of risk assessment and engineering students need to take part also in hands-on training to supplement their learning process. It is clear that one major obstacle to improve safety training is the problem of allowing learners to work directly with hazardous equipment. Traditional approach is based on the use of slide show presentations enhanced by animations or videos. This training method is passive in nature and does not allow for an actual realization of consequences resulting from ignoring safety practices during interaction between the student and the machine. In order to improve the educational practice in this context, the Virtual Reality (VR) technologies could be used. The purpose of this study was to conduct a preliminary investigation to determine whether training through VR simulator is comparable to traditional training in developing the skills necessary for performing identification of possible hazards related to lathe operation. The results of this preliminary study suggest that VR based training has the potential to constitute a valid alternative to the traditional training approach.

An adhesive bonding technology is limited by a cyclic loading of an adhesive bond. The paper deals with a testing of a low-cyclic fatigue of single-lap bonds reinforced with glass beads (B159, a fraction size 90 ± 20 μm). The aim of the research is a study of a low-cyclic behaviour of structural adhesive bonds by means of a scanning electron microscopy (SEM). The research will contribute to a clarification of the fatigue behaviour (low-cyclic) of structural adhesive bonds. The aim of the study was to evaluate a service life of the adhesive bond in terms of its fatigue loading at a low-cyclic shear test. Values of a pulsating loading for the low-cyclic fatigue tests were chosen from this reason for tested adhesives from static tensile test determined a reference value of a maximum force gained at a statical test according to the standard CSN EN 1465. The number of cycles was 1000 at the 30 % strength reached at the static tensile test of the adhesive itself. The cumulative effect of the shear cyclic loading after 1000 cycles showed micro- and nanocracks in the area of the adhesive. The experiment results did not confirm the assumption that repeated cyclic loading could lead to the premature failure of the adhesive bond.

An application of an adhesive bonding technology is limited by cyclic loading of an adhesive bond. The aim of the experiment is to clarify a fatigue behaviour (low-cyclic tests of the fatigue) of four structural two-component epoxy adhesives applied to an alloy AlCu4Mg. The aim of the research was to evaluate a service life of the adhesive bond in terms of its fatigue stressing at the quasi static shear test. From that reason values of a passing loading for low-cyclic fatigue test were chosen for tested adhesives, i.e. 25 %, 50 % and 75 % from a reference value of a maximum force gained at the static test according to CSN EN 1465. The critical value at the low-cyclic fatigue test was determined from the experiment results for the adhesive bond as 75 %. Most of the adhesive bonds did not reach 100 cycles at this value.
It is obvious from the results that the considerable change of the adhesive bond strength did not occur after 100 cycles at the passing loading corresponding to 25 % and 50 % of the average maximum strength of the adhesive bond. The average fall of the resultant adhesive bond strength was in the interval 3 % to 11 %.

This paper focuses on the structural design of screw tools in briquetting presses used for the production of solid, high quality, bio fuels. The primary objective is to analyse the screw tool geometry and determine a procedure for its design, specifically the theory involved with the pressing tool and force relations which are necessary for the verification of the proposed tool geometry and its strength analysis. In designing the main drive of the press, procedures for determining frictional performance of the screw press are used. Familiarity with the above mentioned procedures forms the basis for research into new tools in screw briquetting presses that will improve the service life and competitiveness of the technology.

Aluminium bronzes can find use in many engineering applications thanks to their excellent properties, predominantly high corrosion resistance, good ultimate tensile strength, fatigue strength and creep strength. Yet, their mechanical properties can still be improved, most importantly by appropriate heat treatment. The type of heat treatment is typically chosen with regard to the desired properties of the product and its service conditions. This paper attempts to summarise the microstructural changes which take place in aluminium bronzes during heat treatment. Another objective of this study was to map the potential of a certain type of aluminium bronzes for undergoing martensitic transformation. The methods, which were chosen for assessing the results of heat treatment with regard to their availability, included measurement of hardness and observation of microstructure using light and scanning electron microscopy, Additional tools for evaluation of microstructure comprised measurement of microhardness and chemical analysis by EDS.

This paper deals with evaluation of the controlling processes service reliability of degradation processes leading to embrittlement, fracture at elevated temperatures, fatigue and fatigue fracture with the possible effect of corrosion and with interaction of all the previously mentioned processes.

The paper deals with the strength conditions assessment of new design of modern railway bogie through FEM analysis. The bogie, which was developed as part of European structural funds project, is characterized mainly by better dynamic properties while driving on the track, higher safety against derailment and lower negative effect on the track (reduction of wear). For analysis of bogie frame, there has been created a substitute simulation model. Results from calculations and prototype tests prove, that investigated design of new construction satisfies strength conditions.

Integral stringer panels can attain weight reduction in primary aircraft structures, but do not contain the physical barriers for a fatigue crack growth. One of the promising techniques for prolonging a fatigue crack growth is bonded crack retarders made of materials with high stiffness. An experimental study was done on two specimens with different geometries. High strength bonded straps made of corrosion resistant steel AISI 301 were adhesively bonded to Center-Cracked Tension (CCT) specimens made of aluminium alloy 2024-T351 and fabricated by a high-speed machining process to promote fatigue crack growth retardation. Specimens were tested at a constant amplitude load. The study concludes that the fatigue crack growth life can be significantly improved. Experimental results were compared with a prediction based on the VCCT technique and the NASGRO equation.

This paper enhances an innovative way of preparation of the composite materials by powder metallurgy. Magnesium-fluoride composite material prepared by spark plasma sintering exerted improved corrosion resistance. Magnesium powder was coated by boiling of Mg powder in concentrated NaOH and subsequent immersion in HF. Treated powder was successfully compacted via spark plasma sintering. The composite material with a continuous network of MgF2 is prepared and it exerts improved mechanical and highly enhanced corrosion resistance compared with the pure magnesium.

With increasing complexity of machinery and products manufacturing the strict requirements for quality and, reliability of the measurement equipment and systems plays significant role in production system and quality assurance in terms of customer satisfaction. In nowadays automotive industry in connection to ISO/TS 16949:2009 there has been observed a strong confrontation with request for proof of suitability for use of selected gauges for a specific operations. An appropriate methodology allowing to determine a gauge the most suitable for a given operation is Gauge Reproducibility and Repeatability study (GRR or R&R). The GRR takes into a consideration the variability of produced parts, operator`s approach, and whole measurement system. The article deals with a description and the adequate methodology, and the experimental implementation of GRR in manufacturing quality process assurance in order to set up and continuously improve the quality level in automotive parts production.

The abrasive wear of pulley surfaces at winding of the ropes causes changes of the shape and quality surface of the groove and has influenced lifetime of the skidding machine. The pulley is made of steel C45E without heat treatment and its structure is not suitable for the abrasive wear of the pair metal-metal. Contribution describes a research aimed to changes in material structure by the heat treatment. The pulleys (first one in original state and second one after heat treatment) were tested in operating load at skidding during 320 hours. After experimental test, measurable properties as weight loss, groove dimensions of the pulleys were compared. On the samples from the pulleys, material resistence to wear was tested too. Another alternative for change of material properties would be an aplication of various types of weld deposits on the steel C45E. We have examined the quality of weld deposits and compared their hardness and microstructure. The results of experimental tests resulted to recommendations for practice.

The article deals with hardness tests and dimensional and shape precision analysis of construction and agricultural machinery components, namely with the clamping head and case of hydraulic hammer. The clamping head is made of 41 4220 class (1.7131, 16MnCr5) construction stainless steel and the case is made of 41 5130 class (1.7218, 25CrMo4) construction stainless steel. The micro hardness was measured on VICKERS LM 700 AT hardness tester, according to the national standard STN EN ISO 6507-1: this procedure includes injection of a diamond regular four-bladed pyramid with a 136° peak angle into the tested material with following parameters: objective lens X50, load 10 N, indentation time 10 s. The average HV micro hardness value was determined from 10 measuring points (distances) on 70 samples of the hydraulic hammer case and from 10 measuring points (distances) on 200 samples of the hydraulic hammer clamping head. To measure dimensional and shape accuracy, Perthometer MAHR, equipped with PCV 350 slider unit with sensors with 350 mm length range and a mobile 6-axis 3D measuring arm Romer Absolute Arm 7535 with a working range of 3.5 m were used. This way, basic contour elements were determined: radii, distances and angles. Using the mobile 3D measuring arm, the tolerances of circularity, coaxiallity and perpendicularity were also measured. Technical drawings, contourrograph measuring protocols and tables of dimensional and shape precision deviations are listed in the conclusion of the article.

The paper deals with the design of a special machining tool for efficient production of detail on the T-groove of the clamping part. The introductory part of the paper is focused on introducing the Czech company. The practical part of the paper deals with the analysis of the existing state of machining of the clamping body and of the production of the T-groove detail and proposes an innovative solution in the form of more efficient machining process (partial production modification), which consists in the development and production of a special tool with replaceable inserts. The main reason for this partial modification is a significant reduction in unit machine time in the production of the T-groove detail on clamp body parts. Part of the contribution is in the process of streamlining the innovation made in the form of changes to the manufacturing process and the design of the cutting conditions required to produce the T-groove detail on the clamp body parts. The contribution is completed by a technical and economic evaluation, which is related to the analysis and comparison of both proposed production variants in terms of machine times, tool consumption / replaceable inserts and total production costs for the T-groove detail production on the clamp body parts.

In this work, the microstructure and mechanical properties of three types of high-speed tool steels (Vanadis 60, ASP 2052 and S 705) were studied. The steel S 705 was made by conventional ingot metallurgy technology, and other types of steels were manufactured by powder metallurgy technology. The studied steels were examined both in the soft state and further in the hardened condition with subsequent tempering. Microstructure of metallographic cuts and fracture areas was studied by electron microscopy. Hardness, tensile properties and notch toughness were determined. Significant differences in the properties of steels in both studied states have been documented.

Paper is focused on the area of the energy devices working under the higher temperatures and pressures. It deals with repair of new and operational-loaded components of steam and gas turbines (valve and turbine chamber, transmitters, vane carriers, flap-lockable valve bodies and so on). Generally, there occur different types of defects at production and operating of these parts. Many defects are caused by casting (shrinkage cavities, pores, cracks) and fatigue defects. Eventually, there can occur also production defects. Moreover, most of the defects in the mentioned parts generally take effect not until during the subsequent technological operations. However, in such phase of production, only welding technology can be used to repair the given part. That's why as a goal of this paper there was to find such repair welding procedures which ensure the serviceability of mentioned devices in the standard mode indeed at application of the lower tempering temperatures in comparison to the commonly requirements for material GX12CrMoVNb9-1. Lower tempering temperatures have a strong influence on elimination the deformation as well as on the surface oxidation of the machined components.

The rolling process is widely used to manufacture high-performance splined shaft components. However, there is a convex at root on free end of spline formed by rolling with round dies. However, the analysis and representation of this forming problem are difficulty due to the complexity of motion and multiplicity of processing parameters. This paper concentrates on the corner filling problem, and a physical analog experiment was designed to investigate the problem. The physical experimental results indicated that the designed experiment can reflect the formation of convex during spline rolling process. The finite element analysis of the physical analog experiment process was carried out to study the influences of friction condition and end shape of billet on convex at root of rolled spline. The results indicated that the height of convex will be reduced with increasing friction condition; the height of convex can be reduced by optimizing the end shape of billet. The results of present study provide a basis for optimizing and controlling the forming quality on free end during spline rolling process.

In the article the issue of perspective running parts for freight cars of new generation is considered and additions to the outdated existing classification of bogie are developed, namely introduction of such types of suspension is suggested.The results of theoretical studies are presented by means of modeling the movement of the car in the software "Universal Mechanism" to determine the influence of the first stage of spring suspension in Barber type bogie (type 18-100 and analogues) on energy efficiency (resistance to movement) and the estimated value of the decrease in resistance to movement.A concept for a fundamentally new design of a freight car bogie for high-speed traffic has been prepared, based on fundamentally new technical solutions with elastic-dissipative bearing elements, as well as a concept for the modernization of the Barber-type bogie (type 18-100 and analogues) by introducing axle suspension on the 1520 mm gauge.

This article is interested about drilling the holes to the alloy wheels. Tested were drills to drilling holes for screws and service holes. For screw holes was tested the three-stage drill with inserts from polycrystalline diamond. Drilled are two different diameters and the transition spherical or conical surface. The service holes were drilled with cemented carbide drill availible from Mapal labeled Mega-drill-Alu-180. During test, was modified the geometry of the drill and we watched what will be the effect of applied modification. Tested was seven variants of regrinding the drill. We evaluate the surface roughness, but also if the drill has the right position and not be pushed away from its axis. Finally was tested drill with three edges. This drill bit is from company Mapal labeled Tritan.

Quality of high-pressure castings is influenced by many factors. Structure and mechanical properties of these castings are mostly influenced by properties of casted material, technological parameters and thermal conditions in die casting mould. Thermal conditions in system casting - die casting mould is ensured by tempering system. However there is problem with thin cores and thin protrusions of die casting mould which is not possible to keep on the optimal temperature during casting by commonly available methods. Thus there is overheating in these places. It leads to the porosity of casting and also to the unsufficinet treatment of critical places of moulds which causes the lowering of their service time. With regard to the increasing requires on the castings quality is in practice searching still new possibilities how to cool down these critical places. One of the possibilities is to ally cooling by liquid CO2 into such places. This paper deals with the monitoring liquid CO2 cooling effect that is applied into the die casting mould core.

Adhesive bonds are very often applied in various climatic conditions and environments. Each environment is of specific properties which basically influence entire strength and reliability of an adhesive bond. The influence of the surroundings temperature on the strength and service life of the adhesive bond is one of the most important factors which has to be taken into regard by a designer when designing the bond. However, during a transit or a storing the adhesives can meet much higher or lower temperatures than it is recommended by a producer. The aim of the experimental part is a determination of the influence of the storing temperature in the interval -20 to 100 °C on the resultant strength of the adhesive bond. Two-component epoxy and acrylate adhesives which are used as the constructional ones were used for experiments. The subject of the research was the adhesives which are not specially determined for using in high or low temperatures. From the results it is obvious that the packing type is essential for a transfer of surroundings temperature into the adhesive. Higher storing temperatures (temperatures exceeding 60 °C) affect in a negative way the adhesive bond strength.

The paper describes the surface roughness measurement of functional parts of tools for minting coins. The coining dies were coated with three types of coatings - CrN, TiCrN and WC/C. Roughness of the coining die surface is a very important factor for the quality of a struck coin. The quality of specific coatings on the coining die surface was evaluated by a contact (Hommel Tester T500 roughness measurement device) and contactless method (microscope Sensofar PLu neox) by using optical interferometry and confocal microscopy. Results from the shop measurement gained by using the roughness measurement device were compared to the laboratory measurements gained by using microscope. Moreover, results were illustrated in the graph. Measured values were identical. Only the CrN coating showed bigger difference. Minimum roughness value was measured on the coining die with the TiCrN coating. The WC/C coating reached the maximum roughness value. 3D visualization method of surface roughness using software Gwyddion proved inappropriate for burnished surfaces.

Surface integrity reflects the properties of a material after it has been subject to some type of manufacturing process or modification during machining process and surface integrity can also have a great impact on a parts function. The changes limit the component quality or in the same cases performed the surface as an unacceptable. It has long been known that the method of surface finishing and combination of surface roughness, residual stress, cold work, or phase transformations strongly influence the service performance of manufactured parts as fatigue or corrosion. The main aim of the article is testing a high-productive reaming tool type MT3 with respect to different values of tool-life because holes making among the most important operation in machining and one of the most common in drilling operation.

Plastic injection process is one of the techniques used to manufacture plastic products. The technique is widely used due to its higher and faster production capacity and low cost. However, production process problems are often found, one of which is inappropriate process parameters settings, which may cause product defects. This paper presents a method using combination of Taguchi method, Moldflow simulation and PSO to optimize plastic injection molding process parameters. Moldflow simulations were run to obtain volumetric shrinkage values resulting from each combination of parameters setting selected by means of OA. In adopting S/N ratio technique of the Taguchi method, the study adhered to the principle of "the smaller the better". The ANOVA method was also used to analyze the effect of each process parameter on volumetric shrinkage and a regression analysis was used to establish the equation used for the application of the PSO method to optimize plastic injection process parameters. This method was applied for the production of number plate brackets from PP AZ564 material. The study concluded that the application of the combined Taguchi-Moldflow-PSO method could reduce volumetric shrinkage from 6.05% to 4.24%.

Under the influence of heat load and Zn diffusion in resistance spot welding of galvanized steel sheets, significant changes occur on the contact area of CuCrZr welding electrodes which lead to their erosion damage. Changes, causing wear of electrodes not only affect the welding process but also the quality and properties of the weld. Apart from the traditional solution (for example, the so-called "Slope" welding current) the wear of the contact surfaces can be affected by using the barrier layers - coatings. Main goal for the use of material barrier is to minimize the structural changes caused by Zn diffusion, erosion and higher heat resistance of the electrode. Recent studies have shown that such a suitable coating is a multilayer system (Ni/TiB2).
This paper is focused on the assessment of changes in the contact area of the electrodes and the barrier layer Ni / TiB2 after compila-tion 0, 1, 5, 20 and 100 welds on galvanized steel sheets type HX220BD Z100MBO.

The main aim is testing the basic properties of cobalt super alloys, under its own brand name HAYNES, marking No. 188, at machining and propose the most suitable cutting materials and machining parameters. The superalloys are developed for elevation of temperature service where relatively severe mechanical stressing is encountered and high surface stability is frequently required. The cobalt-based alloys have been in use for several decades in the manufacturing of various components. Although technology development rises in chipless machining such as moulding, precision casting and other manufacturing methods, the machining is still number one, at piece production which is typical for energy and chemical engineering. The driving force for their development still has been requirement of higher operating temperatures for many manufacturing fields in industry area.

This article deals with simulations of the welding process for applications of practice using SYSWELD software. Simulation of welding at the repair of high-pressure gas pipeline with steel sleeve with composite filling is presented in this paper. Two welds connecting the distance ring and gas pipe were simulated. Structure of programme SYSWELD and repair of high pressure gas pipeline with steel sleeve is described in theoretical part of article. Preparation of boundary conditions for numerical simulation on real sample and numerical simulation of welding is in experimental part. Thermal fields, residual stresses and hardness were simulated. The results of the numerical model, which are listed in article except for residual stresses are compared to real experiments. This article mainly describes the numerical simulation capabilities in welding simulation programme SYSWELD.

Welding of the dissimilar weld joints is allied with some technological difficulties that might affect the operational time of the construction. Between the main problems belong presence of residual stresses and inappropriate microstructure of the heat affected zone on the side of ferritic steel resulting to increased hardness. These factors are significantly influenced by heat input during welding, its appropriate control and welding sequence. Optimisation of the heat input and welding sequence requires large amount of experimental work. Recently, numerical analysis of welding based on finite element models became a successfull tool for prediction of material behaviour during the process. This article deals with numerical analysis of austenitic X5CrNi18-10 and ferritic S355J2H steel welding.