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Lattice structures are one way to reduce the weight of a component while respecting its strength requirements. These structures are based on cubic cells, therefore, they are not fully applicable to rotating parts which should be lightweight. This article particularly addresses this issue. A solution is sought for how to adapt lattice structures for a milling cutter. The final redesign of the topology allows a continuous flow of generated stress into the whole body of the cutter. Further, the solid part of the milling cutter is modified for Metal Additive Manufacturing (MAM) and the functionality of the optimised cutter is verified by Finite Element Analysis (FEA). The results of the analysis are compared with a conventional cutter with the same outer shell. The findings from the static analysis indicate that the milling cutter can be considered to be competitive.

In this work the influence of selected elements (Sn, Pb, Bi and Sb) on microstructure and mechanical properties of commercial AlSi8Cu2 alloy at four different temperatures (20, 100, 200, 300 and 350 ° C) was studied. The influence of individual elements and their combinations was studied. The content of elements in the range of 0.1-1 wt% was studied. Significant influence of these elements was found from 0.5% content especially at elevated temperatures.

An aim of the research is mechanical properties evaluation of the polymeric particulate composite based on the pine seeds production residues, i.e. the pinecones. Current trends in composite materials field are a substitution of synthetic fillers by biological fillers. An adhesive modification by biological fillers can improve its mechanical properties and reduce cost, which reduces total costs for composite system production. The polymeric adhesive was modified by the filler with concentration 30 wt. % and tested on mechanical properties i.e. the tensile strength, the elongation at break, the hardness and the impact strength. Results of the statistical analysis proved significant difference between measured values (p

This authors presented article deals with the size of heat affected zone (HAZ) at specific technological processes (cutting and welding techniques). Armox 500 steel was selected and used to perform all realized experiments. Even before the start of the experiments that investigated the effect of HAZ on cutting and welding, it was necessary to subject the investigated Armox 500 steel to basic experimental measurements with regard to its chemical composition, fundamental microstructure and mechanical properties. The microstructure was performed on Neophot 32 optical microscope. Chemical composition was analysed on the spectral analyzer Spectrolab Jr CCD. Mechanical properties, like nanohardness H and reduced Young modulus Er were subsequently measured on Hysitron TI950 Triboindenter with a Cube Corner measuring tip, and evaluated by software Triboscan. Based on the measured values, a 2D nanostructure of the distribution map of s H and Er was evaluated in Matlab. This scientific research, together with all measured and calculated results, is the fundamental that will help to optimizing the quality and used all these results to optimize presented material and technological processes.

The main topic of this paper is the presentation of the keynote of implementation of the newly designed steering mechanism for a tricycle with the electric powertrain with two wheels on the rear axle. On the present, three-wheeled road vehicles with two wheels on the rear axle are wholly dependent on the standard steering mechanism, which main task is the rotation of a front wheel about the steering axis in order to ensure the change of direction in curves. These vehicles are characterised by the relatively poor overturning immunity in a curve. Therefore, in our workplace the new steering mechanism was developed, which is intended to be mounted just in such three-wheeled vehicles construction. The main principle feature of our innovative steering mechanism consists in the additional lateral movement of the front wheel of a vehicle, when it is driving in a curve. Thus, a tricycle using this newly designed steering system can run in curves at greater speed and driving is safer. In this paper, there are presented the working principle of the newly designed steering system as well as dynamic analyses of a three-wheeled vehicle when it is running in curves.

The production of precise castings by investment casting becomes an increasingly important manufacturing technology and many of isues of this method have to be addressed. This paper deals with evaluation of critical points on wax patterns of small blades. After the casting of certain product, the casting had a deviation from the required dimension. Investigation revealed that the effect on the resulting dimensional deviation is not only the casting process but also the wax pattern injection process itself. The engine and turbine blades are one of the most important parts in turbine or aircraft engine machinery. Casting deformation is an important feature of evaluation the quality of the turbine blade. In order to control the deformation of the turbine blade during investment casting, a novel compensation method based on reverse deformation was proposed in this study. The article investigates and evaluates critical points for deformation of the blades after their production on wax-press machine. In addition, the effect of the pre-deformation preparation and the human factor influencing effect during assembly is evaluated with the main aspect of not machining all surface of small blades.

Tubes of super-heaters and heaters used in conventional power plants are exposed to coolant and high temperatures. The growing oxide layer on the inner surface reacts over time as a heat insulator on the water side and reduces heat transfer through the wall of the tube. A relatively thin oxide layer already contributes to the boiler efficiency and causes a permanent overheating of the tube wall. As a result of overheating at the site, the intercrystalline cracks leading to the bursting of the tube are developing. The secondary problem of the growth of oxide layer thickness is so-called exfoliation. For non-destructive evaluation of the thickness of the oxide layer directly at the power station, ultrasonic method (UT) can be used with a high frequency probe. In order to verify the accuracy of the measurement and the qualification of the ultrasonic testing methodology, light and Scanning Electron Microscopy (SEM) was used on specimens that were removed from the super-heater after the UT measurement. The standard longitudinal cut surface imaging in BackScatter Electrons (BSE) and Energy Dispersive Spectroscopy (EDS) analysis for accurate thickness determination with the chemical composition of the layer confirmed the accuracy of the UT measurement.

This paper discusses the possibility of increasing the surface load capacity in C60E steel gearings by applying DLC thin coating. It describes the effect of tribological characteristics, such as friction coefficient, wear, adhesion and hardness of DLC coating on convex-concave gearing (C-C). The average thickness of DLC coating is 1.2 μm. Delamination of the DLC coating was recorded at a load of approximately 50 N. The friction coefficient of the DLC coating was 0.09. The nano-hardness of the DLC coating was 14.4 GPa. The results of the tests to scuffing on C-C gearings on the Niemann tester show that the DLC coating deposition occurred at load level 5. The complete removal of the coating was preceded by gradual thinning. After its removal, the wear continued substrate, where the traces after milling filled-up with the substrate metal.

A constantly growing competition in world economy results in an increasing demand for solutions enhancing both the effiiency of enterprises and the quality of goods produced. A solution which meets both requirements is robotization of production processes, i. e. replacing human labour with the work of industrial robots on the positions where tasks are monotonous, onerous or dangerous. The paper presents the economic analysis of the use of robots in production processes, as well as its technological conditioning. On the example of robotization of processes in the enterprise producing semi-trailers, the method of calculating the re-turn on investment was presented and an analysis of the labor costs of the worker and the robot at a given workplace was made.

This paper will investigate the changes in size and amount of the microstructural features in secondary aluminium casts associated with different wall thickness. The experimental samples were casting into the sand mould. The changes were documented and assessment by using optical microscope and methods of quantitative analysis. The results shows that increasing wall thicknes lead to formation larger second phases and coarsening of the matrix, which lead to decreasing mechanical properties.

Electronic Speckle Pattern interferometry (ESPI) is a non-destructive optical method for studying surface deformations. It relies on the interference between diffusely reflected light from the test object and a reference beam. This is one of the most sensitive interferometric technique, so that we can measure sub-micron level displacements either in plane or out of plane. In this study, experimental investigation of vibration behaviour of square copper alloys plates by electronic speckle pattern interferometry is employed. Resonant frequencies and corresponding mode shape are obtained experimentally using the introduced method. Frequencies of resonant vibrational modes depend on elastic properties of material, especially on Young's modulus E, Poisson ratio μ and density of material ρ. This fact gives us in principle the possibility to estimate th e elastic constant of materials from the vibrational measurement. The numerical calculations by the finite element method are performed and the results are compared to the experimental measurements.

The paper deals with the physical-chemical effects of a blowing agent on production the cellular metal systems (in this case aluminium foams). Based on the isothermal concertation and pressure curves for the H-Ti system and by using the maximum gas volume obtained from equation of state, there was applied the blowing agent to 1 kg of AlSi12 aluminium alloy. Moreover, using relation to determine aluminium foam relative density (ρ REL) from alloy AlSi12, there was done prediction to determine density of 1 kg metal foam from AlSi12 alloy at different blowing agent contents from 0.1 up to 1.5 wt% of titanium hydride TiH 2. These isothermal calculations were compared with the density of aluminium foal from alloy AlSi12, which was produced by an industrial process. Basic mechanical properties were subsequently measured on the produced foam samples.

During design process materials and their shapes selection is usually performed unsystematically, selection is mostly based on previous experience, although this is the most influencing part during mechanical design. This paper is devoted to the application of the material-shape factors and indexes to the standard bicycle frame. Paper to show the method with material-shape factors and indexes and how to use it for a simply and fast redesign for a different material and shapes. The whole method is descripted in detail for two examples and the results are verified by FEM analysis.

An application of external fixator is a surgical method for the treatment of large bones fractures. This method has been proposed already a century ago, but despite the extensive development of science and technology, the fixator is often used in the original state of the proposal. [1] Therefore the patient and surgeons are dissatisfied with high weight and poor mobility of fixator during surgery and healing process. [2] Due to this fact it is necessary to apply new 3D technologies into this field of orthopedics and thus improve the current state of this tool. [3] In an account of this information, the 3D model of a new composite external fixator was created. In the research, the composite fixator was analyzed by the finite element method (FEM). Based on the results of FEM and the surgeon's requirements, the composite fixator was further improved and the final results show that the composite fixator proposed by the FEM is able to transfer the applied load from a patient. Therefore the data indicates that the implementation of composite material will further improve patients comfort, the healing process and the precision of surgery. Based on this fact, the mold has already been manufactured and the process of completing the product has started.

Tool life changes according to a curve presenting two extreme values depending on the cutting speed. Besides the well-known Taylor formula, several other functions describe tool life, mainly for the 3rd speed range beginning with a tool-life maximum. In earlier studies the authors suggested a tool-life function valid for the whole speed range. Here the machinability of hardened steel is being investigated in a wide range of cutting speeds. The intention of this study is to work out a method for the physical interpretation of tool degradation defining the tool life. For this purpose the nonlinear differential equation of wear rate is applied. During the experimental work the tool life was measured when boring a 100Cr6 hardened workpiece of 75 mm diameterin the speed range vc=10…120 m/min with a feed rate of f=0.075 mm/rev, depth of cut ap=0.1 mm, γr=-5° and the life criterion Wcr=0.4 mm. The results proved the supposition that at a speed smaller than the tool-life maximum it is abrasion and adhesion that causes the tool deterioration, while above this speed, the thermo-activated degradation process plays an increasingly large role as speed increases. Calculating from the results of the cutting examination, the activating energy of the degradation process is Q=136±29 KJ/mol, on the basis of which it is likely that the degradation of the tool material occurs through the recrystallization of the surface layer from cubic into hexagonal, causing the surface layer to wear out more rapidly.

Determining transformation temperatures of novel steels is an important step towards finding parameters for their heat treatment. In advanced high-strength steels for Q&P processing (Quenching and Partitioning), the crucial processing characteristics are the temperatures of the start and end of austenitization and the Ms temperature. Q&P processing is characterized by quenching from a full-austenitization temperature to below the Ms, and subsequent holding at the partitioning temperature. This leads to martensitic microstructures with retained austenite between martensite needles and to ultimate strengths above 2000 MPa and elongation levels up to 10%. Several AHS steels containing 0.4% C were manufactured and cast for this experiment. Their main alloying additions were manganese, silicon, chromium, molybdenum and nickel. Their transformation temperatures were first calculated using the JMatPro software. The values were validated by dilatometry measurements. Based on these results, a Q&P process route was designed and put to test. The resulting microstructures were documented using optical and scanning electron microscopy. Strengths of more than 2300 MPa and up to 11% elongation levels were obtained.

The main goal of this paper is to present experiments exploring the effect of cryogenic treatment on the properties of cemented carbides. The experimental materials were chosen from three basic groups of cemented carbides with different binders and different WC grain sizes. One half of the specimens were cryogenically-treated, whereas the other half were in the as-received condition. The specimens were ground and polished using metallographic procedures. Effects of cryogenic treatment were studied by metallographic observation using light and scanning electron microscopes, by X-ray analysis of phase composition and by measuring Vickers hardness and KIC fracture toughness. It was found that residual stresses in specimen surface decreased after cryogenic treatment. The KIC fracture toughness of the specimens increased.

This paper demonstrates the new multi criterion decision making (MCDM) techniques were used, i.e. the weighted aggregated sum and product assessment (WASPAS) technique. This involves the modified air abrasive jet machining (MAAJM) of Nickel 233 alloy using carbide coated nozzle in 3mm dia with three responses are considered as against the process variables of injecting pressure, standoff distance, and abrasive mesh size. The optimal combination of MAAJM process parameter for simultaneous minimization of taper angle, surface roughness and maximization of MRR are injecting pressure of 0.686MPa, standoff distance 9mm and abrasive mesh size 400μm with 3 diameter carbide coated nozzle. The optimal results attained with the WASPAS technique demonstrated to good relation with another technique multi objective optimization rational analysis (MOORA).

The aim of this experiment was to investigate the influence of the Sr modifier in the Al-Si eutectic alloy on the structure change and its mechanical properties. For this reason, an Al-Si7Mg0.3 hypoeutectic silumin alloy was modified with the aim of improving the mechanical properties of the material, mainly by increasing the ductility and strength. The subject of investigation was analysis of morphology of excreted eutectic silicon. In order to investigate the surface, metallographic cross-sectional specimens were prepared using light and electron microscopy. A static tensile test was performed for detailed examination. It has been found that the addition of the AlSr10 modifier and, over the time of modification of 1 to 2 hours, has increased the mechanical properties, in particular the ductility.

Present work is focused to determine the cause of higher wear of castings made of secondary (recycled) AlSi12Cu1 cast alloy after switching supplier and the morphological evolution of Fe-rich phases has been documented. As recycling of Al-alloys becomes more common, sludge will be a problem of increasing importance due to the concentration of Fe, Mn and Cr in the scrap cycle. The tendency of Al-Si-Cu alloys to form sludge Fe-rich particles can be predicted by the sludge factor (SF) equation, which represents an attempt to gather the combined effects of Fe, Mn and Cr. Sludge phases are hard and brittle phases which can compromise the machining operations, with a considerable effect on the cutting tool life, and even more degrade the mechanical and physical properties of the component. For study and identification of intermetallic phases' was utilized standard etching (Dix -Keller, H2SO4) and for element composition was used X-ray analysis. The results show that coarse sludge Fe-rich phases appear in the alloy with 0.945 wt. % Fe combined with higher content of Cr, while the Chinese script or needle-like Fe-rich phases appear combined with Mn. At the same time, a higher sludge factor was calculated and the ratio between the amount of Fe and Mn was not respected.

Al-Cu-Mg based alloys are often used in the automotive industry. There are characterized by high strength characteristics but poor corrosion resistance, which appears to be problematic in this sector. The manufactured blanks of these alloys may be protected by some of the barrier protection methods, including cladding. Semi-finished products made of these methods can be protected against corrosion by a thin layer of aluminium oxides - called clad Durals. The surface layer creates a stable and durable Al2O3 layer, which provides corrosion resistance, which leads to an extended service life of the piece.
However, this type of protection is adversely affected by the effect of copper diffusion, which is dependent on the heat treatment mode of the alloy. Temperature and temperature hold are the main factors influencing the diffusion process. In the solution annealing of aluminium alloys, the temperature is in the range of (470-500) ° C, resulting in intense diffusion processes at the inter phases interfacial.
The paper deals with the analysis of the influence of the heat treatment regime on the corrosion resistance of Al2024 alloy sheets (AlCu4Mg1 type alloy) provided with an Al1050 alloy clad coating on both sides in a corrosive salt mist environment in accordance with EN ISO 9227, which is supposed to have a positive effect on extending the service life of a car component.

There are a large number of special methods for exploring the internal condition of materials on the basis of eddy currents. A major use of this method can be seen in surface engineering, particularly in studying some state quantities of surface integrity. It is also an irreplaceable tool in surface engineering. The reason is that no other affordable method provides information on both the surface and the sub-surface regions, as the latter are difficult to reach by most other inspection methods. It must be noted that the sub-surface region is significant, and dictates, to a large extent, the behaviour of the overlying surface. This article explores another non-traditional application of eddy current inspection. The study presented here involves a use of this non-destructive testing method for carburizing verification and for detecting of amounts of retained austenite.

In the production of plastics tools, due to the high mould price, high demands are placed on cost reduction or shortening mould production times. The price of the injection mould is reflected not only in the price of used injection material but also in the price of its own production.
Mould form cavities were made with different materials and different machining technology (finishing methods). Various polymeric materials were injected into the cavities thus prepared, and the surface quality of the samples was evaluated and compared to the quality of the surface cavities, thereby verifying the copying of the surface of the mould cavity onto the surface of the polymer product. The aim of this article is to determine the impact of technological conditions on the quality of the plastic tool (injection mould) and the future polymer product. In this experiment, they were made by different technological conditions of the shape cavity and their influence on the resulting roughness parameters of tested samples was determined.

The subject of this article is the study of influence of sintering time and sintering additives on mechanical properties and wear resistance. Si3N4 with Al2O3+Y2O3 additives (YAG) and Si3N4 with MgO additives was used as an experimental materials. Compositions sintered for 30 min achieved optimal combination the hardness and fracture toughness - 15.05 GPa and 6.87 MPa.m1/2 for Si3N4-MgO and 14.65 GPa and 5.71 MPa.m1/2 for Si3N4 -YAG. Wear was mostly influenced by the hardness of ceramic materials. The specimen with the highest hardness achieved the highest wear resistance. Wear resistance of ceramics decreased with the grain growth and with the transformation progress of narrow α- Si3N4 phase to prismatic β- Si3N4 phase. The wear resistance of the studied ceramics can be described by model V ~ HV-1. Si3N4 -YAG in comparison to Si3N4-MgO has several times greater wear resistance.

This paper presents some advanced techniques on CAD modelling and CAM programming for 5-axis machining of free-form surfaces. In the CAD stage, based on surface partitioning, the design surface can be created with separate regions such as convex, concave and saddle. Point-based techniques are used to create the original surface and the boundary curves of the regions. Some other CAD/CAM techniques for determining tool sizes and tool orientations are also proposed to generate gouge-free tool paths for each region. A simple B-spline surface was given as an example to demonstrate the proposed techniques implemented in Creo Parametric. The points on the design surface and on the boundaries were generated by a Matlab program developed by the author.

Piston parts of a shipborne labyrinth compressor are mainly composed of a piston and a coated piston rod. In recent years, many studies have shown that the vibration response of coating structure is significantly reduced. Because of the non-contact of the piston, the cylinder case and guide support entirely depends on the piston rod. The lateral jitter can be regarded as the vibration of cantilever beam. However there is no effective method to separate the contribution of hard-coating damping from the damping of composite system. In this paper, based on separating the damping contribution of hard coating, the method of creating the damping mechanism model of piston rod is studied. Firstly, the piston rod before and after coating are tested and the characteristic parameters of vibration, such as natural frequency, damping ratio, vibration response are acquired. Moreover, according to the analysis of the storage and dissipation energy in the uncoated and coated rod, the damping contribution of hard coating has been confirmed. Finally, the Oberst beam theory is adopted to create the damping mechanism model of piston rod which includes both material damping and viscous damping. The correctness of analytical model is also verified by the experiment results.

Crystal segregation is taken as chemical heterogeneity under the micro-scale and it develops during the crystallization process. Alloy crystallization does not take place under a particular temperature, as it happens in the case of pure metals, but it runs under a certain temperature interval. When cooling the melt, various places start development among dendritic cells which differ in their chemical composition. Crystal segregation can be generally defined as chemical heterogeneity developing during the alloy crystallization process, and it can be either en-riched or in contrast depleted with alloying elements and impurities, which are unevenly segregating over the en-tire dendritic surface. In the central part of the dendritic cells there is an alloy, which is depleted with alloying elements, while the edge areas of dendritic cells and interdendrite space present higher concentration of alloying elements. This concentration shows a hyperbolic development; when the central part of dendritic cells area has the lowest alloying elements concentration, while the edge part of a dendritic tree and the interdendrite space show the maximum concentration. The distance between two main axes of dendritic cells is affected by the temperature interval running between the liquid and solid phase of the chosen alloy, as well as by melt cooling rate and temperature gradient during the solidification phase. The shorter distance between the axes of dendritic cells appears under faster cooling, which allows very fast heat dissipation and creates very fine structure of the resulting alloy. The longer distance between the main axes of dendritic cells stimulates greater segregation appearing under slow melt cooling.
Crystal segregation formation of aluminum alloys enriched with alloying elements and impurities cannot be prevented, only its extension can be regulated and it can be suppressed with the correct choice of heat treatment parameters. To suppress the crystal segregation the casts should undergo heat treatment which is called homogenization annealing.

The article discusses the problem and importance of the study of the parameters of interaction between the wheel and the rail. The analysis of the test rig equipment for conducting research was carried out. Conventionally, the methods of conducting research are divided into 3 groups: physical and mathematical models, full-scale test rigs, field tests. Technical solutions for the modernization of the rig equipment of different types are proposed and the results of experimental studies using some of them are presented. For the approximation of rig equipment to the real conditions of operation it is proposed to cool the rail rollers through the use of the Ranque-Hilsch tube; to simulate the stiffness of the track on the rig it is effective to use leaf springs. Tests on a friction machine showed the effectiveness of sand electrification when supplying it into the contact of tribosystem.

In order to enhance the stiffness of the gas film and increase the maximum speed of the rotor, this paper proposes an ultrasonic levitation structure with a cone type bidirectional supporting motor. The performance of the conical-type ultrasonic levitation support is analysed and tested according the relationship between the levitation force and levitation gap. Through theoretical analysis it is realised that the critical speed and vibration mode of the motor rotor is affected by the change of levitation gap in the ultrasonic levitation condition. The experiments with levitation gap and the maximum speed of the motor rotor show the structure can reduce the suspended gap, while simultaneously the maximum speed of the rotor is increased.

The intensity of wear and particles formation are important factors at practical application of rotating machine components, because of negative effects on operability of the machines. The presence of undesired wear particles, for example in lubricating systems, poses a risk in terms of subsequent accelerated wear of lubricated points. In the extreme case, the negative impact of the wear particles leads to seizure of lubricated points. The aim of the research was to compare the classical machining and abrasive - free ultrasonic finishing (bufo) of steel. Ultrasonic set I-4 consisting of the ultrasonic generator (output power 630 W) with working frequency 22 kHz ± 10% was used for preparation of test surface. There were compared three different process fluids containing nanoparticles during abrasive - free ultrasonic finishing. In order to describe machined surface there was used measurement of surface roughness, hardness HBW 2.5/187.5 and results of microscopy. Research was focused on determining resistance of machined surfaces, using a standardized test Reichert M2 tester. Number of wear particles and their morphology are important for practical application. Wear particles were analyzed by automatic particle counter LaserNet Fines-C.