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An important trend today is the continual improvement of product quality with the objective of increased customer satisfaction, but also leading to more effective cost reduction management. Effective quality management in a company also enables increasing production productivity thanks to the increasing amount of top-quality products made and the consequent minimalization of repairs of non-conforming workpieces. This contribution deals with one of the important tools for ensuring quality in the production process using the FMEA (Failure Mode and Effect Analysis) method used in the production of roller bearings for the automobile industry.

In the presented work, static and dynamic properties of two, theoretically identical composite rods were studied. Those two kinds of rod were made of pre-impregnated fibers so called "prepregs". The first of them was made by means of wrapping technology, which is simply just helical layering of one wide tape around a rotating mandrel. The weakness of this method is possible using only for straight parts. That is why a simultaneous deposition of several thinner filaments in a form of tape called winding was used in order to optimize this technology also for curved parts with various cross-sections.
The target of this work was to compile numerical model and experimentally compare flexural strength of the theoretically identical wrapped and wound rods in the static three point test.Further small samples cut and extracted from those rods were subjected to dynamic bending loading on Dynamic Mechanical Analyzer, with various loading speed, in order to obtain also the dynamic properties. The found results and conclusions of this article should provide a basic idea how significantly the manufacturing process could affects the microstructure and real mechanical properties of long fibers composite parts.

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.

Detonation is a specific type of a rapid exothermic reaction, which always involves a detonation wave (in the explosive) and the shock wave (in the environment). Modelling of the pressure wave falls in the fluid flow and interference with obstacles in the flow. The purpose of this paper is to development of simulation model based on the finite element method (FEM) for shock wave propagation in air form the explosion of a spherical charge from TriNitroToluene (TNT) material. The air is the classical ideal gas and explosive material TNT is defined using Jones-Wilkins-Lee (JWL) equation. The computational model is 2D-dimensional model with four node axisymmetric elements. The effect of the explosion on the pressure distribution in the air and rigid surface (ground) is investigated. Numerical solution of the dynamic response was performed using commercial FEM software ADINA.

The usage of aluminium alloys has an increasing trend in the manufacturing industry in recent years. This fact is connected with their ability to combine their very good properties. Characteristics of aluminium are low specific weight, very good thermal and electrical conductivity, and ductility. However, the major disadvantages are low strength and hardness. Therefore the aluminium alloys are alloyed with the elements, which would significantly improve the properties of aluminium. The machining process of aluminium alloys is influenced by many factors that affect the machinability. These factors are for example process conditions, cutting tool material, cutting tool geometry, cutting environment or the chemical composition of the machined material itself and microstructure of the workpiece. Due to the different structures, the machinability of aluminium alloys and pure aluminium is significantly different. Factors such as chemical composition, precipitates, the number and position of soft particles or the strain hardening degree affect the behaviour between the cutting tool and the workpiece during machining. When machining the aluminium alloys, there are some problems such as the surface quality, micro-geometry, tool wear, the chip shape, built-up edge formation, etc. The article deals with the surface defect investigation after the machining process, when on the surface of the material stay the visible "snowflakes" after the turning operation. These "snowflakes" were documented and were performed analysis and observation to find the cause of these flakes.

This study is focused on the effect of pigments on polycarbonate (PC), especially the dimensional stability and flow properties of this material. This polymer is commonly used in the plastics industry and the most common processing of this polymer is injection molding technology. Three different pigments made by Lifocolor company were selected for PC staining. In addition, six different concentrations of aforementioned pigments were used. It is worthwhile to note that the pigments in the polymer matrix acted as a filler. Just like fillers, the pigments also influence the shrinkage of the polymer in both the main and secondary directions. The paper also deals with the effect of pigment concentration on the melt index (MFI). It was shown that the presence of pigments reduces the thermal mobility of the macromolecular chain. Melt flow index changes were also directly tied to the changes of the viscosity, which was also affected by the pigments. It can be expected that the viscosity might not remain the same even at varying shear rates.

This article deals with the experimental grinding of cermet materials. Two types of cermet materials from different suppliers were ground under constant grinding conditions using a diamond grinding wheel. The main aim was to determine the influence of the grinding on the degradation of the grinding wheel and changes in the grinding process. Both types of cermet were ground with the same strategy and the same number of passes. The grinding wheel was analysed during grinding using an optical scanning device to observe the changes on the grinding wheel surface. Clogging and wear of the grinding wheel occurred on the surface as the amount of material removed increased. All grinding tests were carried out without dressing or truing of the grinding wheel. Degradation of the grinding wheel had a big influence on the grinding process in terms of the spindle load during grinding. The roughness of the ground surface was also measured using the optical scanning device. The results from this work will be used for further research of cermet grinding.

This paper deals with the evaluation of the graphite cast iron structure and change of the dynamic behavior dependent on the graphite shape. Structural analysis is focused on the study of cast iron with flake and globular graphite. These two materials have a considerable application in manufacturing due to its specific mechanical and physical properties. The production of gray cast iron is less demanding in terms of the technological process and the quality of the raw materials compared to ductile cast iron but this material is the best for the production of castings. Compared with cast steels are these graphite castings less susceptible to the notch effects of fatigue stress and have a higher value of damping. Internal damping occurs in the structure of the material and can be caused by its imperfection. Computational measurement of eigenshapes and eigenfrequencies was performed using modal analysis in the SolidWorks software environment.

This article deals with the influence of grinding conditions and tilting the spindle on changes in the spindle load when grinding tool steel on a 5-axis tool grinding machine. The experiment was designed to investigate any changes in cutting speed, feed rate or tilting of the spindle. The size of the load is very important, because the load can influence the tool life, the life of the machine components, quality of the surfaces and dimensional accuracy of the components. A medical femoral knee replacement was selected as the semi-finished component for the experiment, as its surface is a good representative of a complex-shaped surface. This article is limited only to the grinding of maraging steel MS1 with a CBN grinding wheel. The second part of this article is focused on the experiment where the spindle load is evaluated and the results of the experiments are compared.

This paper deals with the causes of failure of total hip replacement. Hip joint replacement is one of the most frequently used surgical procedures worldwide. More than 200,000 surgeries are performed only in Europe each year, following early attempts by John Charnley. Currently, more than 340 of the total 4431 implants per year are reoperated in Slovakia. Despite the excellent properties of the titanium alloy, endoprosthesis often fails and the hip replacement is necessary. Common causes are overloading and cracking, static or dynamic. Other causes of failure include injury, implantation failure, manufacturing inaccuracies, and non-compliance with the manufacturing process.

The aim of the work was to evaluate the whole system of the springs of a passenger car. The influence of inflation and the type of tires on the acceleration of the various parts of the car (axle, steering wheel, driver's seat attachment, body shell and acceleration affecting the driver) was investigated. The types of shock absorbers and springs of the passenger car were also examined. The sensors used acceleration and pressure sensors between the wheel and the road using test stands. The benefits and reserves of the individual systems were compared, and in the systems with the cushioning rigidity, all the suspension setups were evaluated. The work was done experimentally in laboratory environment as well as in real operation.

Dynamic load of the improved hatch cover construction for universal open-box type wagon is researched, taking in to account the worse loading scheme - impact of 150 kg cargo from height of 3000 mm. In the case of improved hatch cover construction, dynamic load character reduction up to 50% can be reached, compare to conventional one. Hatch cover model of proposed construction for strength calculation was created. Strength calculation is done by finite-elements method in Cosmos Works software. Calculation of hatch cower durability, considering symmetrical and asymmetrical load cycle are carried out. In the proposed construction, areas with maximum equivalent stresses caused by usual operational load are defined. Results of conducted research can be useful for projection of new wagon generation with improved technical, economical and operational parameters.

Microcellular injection molding is relatively new and progressive technology for production of lightweight constructions. The weight reduction, elimination of sink marks, internal stresses and deformation of products are the main advantages of this unconventional technology. On the other hand, decrease in mechanical properties and poor surface quality are the application restrictions. There are several aspects affecting formation of microcellular structure and final properties of injection molded products. As a one of the most important aspects there is used material. Therefore, the main goal of this article was investigation the influence of different types of thermoplastic materials on the microcellular structure formation and mechanical properties of products. Further, the influence of holding pressure on products quality was also evaluated.

During the operation, a slewing bearing is always subjected to a set of combined loads. It is the source of deformation of ball-raceway contacts, rings, and even supporting structures. In practice, deformation of rings and supporting structures is often neglected for simplification, that is, they are supposed to be ideally stiff. To take elasticity of rings and supporting (fixed) structures into consideration, the finite-element method (FEM) is applied. In slewing bearings, a great number of contact pairs are present on the contact surfaces between the rolling ele-ments and raceways of the bearing. In order to improve the computational efficiency of load distribution of large roller slewing bearing, a computa-tional model using one-dimensional finite elements (nonlinear elements) is presented in this paper. In this model, each roller is simulated by a group of nonlinear elements truss, which has the same load-deformation perfor-mance with solid roller-raceway contacts. The results show that a group of parallel springs can be used to replace the solid roller and simulate the line contact performance between the roller and raceway. Obtained results are presented as graphs.

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.

The paper deals with problem of construction for Weightlifting in CrossFit from point of view of material parameters. The specific structure has to withstand repeated impact loads. Therefore it is also necessary to deal with stress-strain states. Because of behavior of impact loading and elastomers used in FEM computational model, explicit integration scheme and material constitutive models have to be included. To use constitutive models, material parameters have to be well known. In this paper, the 2-parameter Mooney-Rivlin model is used. That is the reason, why this article is focused on obtaining material parameters of elastomers for FEM computational modeling based on their hardness. Mooney-Rivlin parameters can be determined on the basis of the Shore A hardness. There are exist equations which can be used conversion of the mentioned hardness to material parameters of elastomers. The procedure is such that the Shore A hardness is converted to the elastic or shear modulus and then Mooney-Rivlin material parameters are determined from the modulus. But these equations can lead to different results for the same hardness. In this paper, these results are comparison. For create a 3D model the SolidWorks software is used and for FEM analyses well-known the ANSYS Workbench software is used.

Previous work has proposed a process for implementing a lattice structure into a milling cutter body based on clustering in the milling cutter with modified main dimensions of a BCC cubic lattice structure cell. A finite element analysis model has been created to predict the strain and deformation in the struts of the lattice. The prediction made according to static loads demonstrates that the concept of a lightweight cutter meets the strength requirements, though its stiffness does not reach the fully-filled version. The methodologies for creating the FE model are described in this paper. HyperWorks with OptiStruct were used for these analyses. Local stiffness could be improved by varying the strut diameter or using a different type of basic cell for the lattice structure in problematic locations, especially in the area of the connection between the shell of the cutter and the lattice structures.

Nowadays there is a high trend and effort to find a suitable biodegradable metal, whose mechanical properties would be the same or higher to those of currently used biomaterials. Current biomaterials, such as stainless steels, cobalt-chromium alloys, and titanium alloys have superior mechanical properties, machinability, and durability, but are considered nondegradable, and long-term clinical complications may occur. Their biggest disadvantage is that the patient must have undergone a second removal surgery. Therefore, new biodegradable materials have been developed to eliminate the shortcomings of current biomaterials. Magnesium (Mg), iron (Fe) and zinc (Zn) based alloys have been proposed as biodegradable metals for medical application. Iron-based alloys show good mechanical properties compared to magnesium-based alloys. However, both of them exhibit bad corrosion properties, because the degradation rate of magnesium has proven to be high. On the other hand, the degradation of iron-based alloys is too slow in a physiological environment. The corrosion attack of both materials is not typically uniform. Therefore, zinc is proven to be a promising material for this application.

This article deals with state-of-art in the field of handling machines intended for disabled people, which serve for disabled entry of such people and for people with delimited locomotion. It contains calculation of forces, which act in the mechanical system of an electric device during its operation in real conditions, changes of reactions depending on the load and the climbing angle as this solved handling machine will designed for negotiation of staircases. The objective is the functional calculation of a driving mechanism of a stair chair marked SA Alfa, i. e. the calculation of loading forces and their action on the driving mechanism. It will serve in the next step as an input for the calculation of a required power under conditions of occurance of maximal resistance forces, which will be determining factor for dimensioning of driving components of this device.

The given paper is closely connected with the numerical modal analysis of eigenfrequencies and eigenshapes for turbine blades of the turbojet engine with the help of the mathematic modelling. The mathematic model was created in Pro-Engineer program and it was subsequently created to the ANSYS program in order to apply finite element method. Distribution of the stress in the turbine blades is presented in [Pa]. The presented results of the eigenshapes and distribution of the stress are obtained in the graphic form.

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.

This paper deals with monitoring the influence of welding on the mechanical properties degradation in HAZ of welds at aluminium alloy AW 6005 and also with assessing the possibility of utilization the heat treatment to minimize these effects. Workpieces from alloy AW 6005 are mostly supplied in aged state. After application of the temperature cycles during welding, there is a very intensive decrease of the mechanical properties in HAZ. The mechanical properties of the weld metal, HAZ and parent material were evaluated by means of the Vickers hardness. Moreover, influence of annealing and artificial aging on the final mechanical properties of the parent material was also evaluated. Based on the results, there were chosen the relevant heat treatment parameters, which were subsequently applied in order to recover the mechanical properties of welds in the HAZ.

Topological optimization is the process of reducing part weight while respecting strength requirements. This paper focuses on its possible positive consequences for the machining process. The main aim is to carry out a survey to obtain knowledge that will be applied during the topological optimization of a milling tool. According to all the indicators, the efficient implementation of lattice structures into the milling concept has the potential to achieve a high level of innovation, since the functional weight reduction of the tool allows for higher dynamics of the cutting process. The modified rigidity of the milling cutter and vibration absorption can extend the life of the cutting edge, and such a milling tool would provide a competitive advantage on the tool market.

Polymer injection molding is the most used technology of polymer processing nowadays. It enables the manufacture of final products, which do not require any further operations. Working of shaping cavities is the major problem involving not only the cavity of the mold itself, giving the shape and dimensions of the future product, but also the flow pathway (runners) leading the polymer melt to the separate cavities. This paper shows the influence of cavity surface roughness, polymer material (with different flow properties) and technological parameters on the flow length of polymers into mold cavity. Application of the measured results may have significant influence on the production of shaping parts of the injection molds especially in changing the so far used processes and substituting them by less less expensive production processes which might increase the competitiveness of the tool producers and shorten the time between product plan and its implementation.

Within the context and term of quality it can be comprehended as a subjective character. Every individual has its own requirements, expectations or standards on specific product or service. Thus, these parameters are then connected and defined by different priorities. Many of the customers are willing to pay more money for increased quality of bought product however many of them are forced to decrease their requirements due to the costs and they have to be satisfied by products with lower quality or lesser amount of defined parameters. The main aim of the paper is to observe and analysis of cost system and its effect on product quality through the monitoring, analysis and evaluation of production costs in selected organization. Due to the comprehensive evaluation of the effects of investments on the resulting quality in selected organization a various methods was employed. Among used methods was comparison of investments into production quality by data analysis according to PAF model, mathematics and statistical parameters and Pareto's analysis. There were suggested individual steps by utilization which allows determining, evaluating and creating an individual system of observation and evaluation. Such a system of costs analysis is then suitable for selected companybut not limited to it. The utilization of such a system is therefore applicable at any company or organization which is focused on custom small-series production.

Metal additive manufacturing provides an efficient way of processing metallic cellular structures. This relatively novel way of production is based on a powder bed which is melted using a powerful laser. Despite the advantages of this production technology, differences in geometry are observed between the CAD model and the manufactured structures. With this in mind, a series of thin struts were made and their geometry analysed using optical-scanning microscopy. Various building directions and strut diameters are studied. The effective stiffness of struts are measured and verified by tensile tests. The results point to higher strength of inclined struts than perpendicular specimens.

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.

Cutting tool wear monitoring is one of key problems in automation of machining processes. Apart from the cutting tool wear monitoring for the cutting tool change and cutting tool failure, cutting tool wear monitoring may be one of the components for the adaptive control of a machining process. This paper is focused on the design of turning cutting tool wear sensors of the system flap - jet principal with increased extend. On the geometric principles in cutting with a turning cutting tool, the relations among the output of jet mouth, clearance angle and cutting tool wear were expressed. Two variants of turning cutting tool sensors were designed and experimentally verified. The results of experiments have proved the possibility to apply cutting tool wear sensor of the system flap - jet principal with increased extend in practical use.

Beside cutting speed, shift is another important parameter of machining. Its considerable influence is shown mainly in the workpiece machined surface microgeometry. In practice, mainly its combination with the radius of cutting tool tip rounding is used. Options to further increase machining productivity and machined surface quality are hidden in this approach. The paper presents variations of the design of productive cutting tools for lathe work and milling on the base of the use of the laws of the relationship among the highest reached uneveness of machined surface, tool tip radius and shift.

The paper deals with a design and construction of an implant prototype of a knee-joint femoral component with a complex shape mathematic description especially of functional (articulating) surfaces. The core of a technical solution labours under the thought of casing of femur distal part with a shell of certain thickness whereas a special area is used as a referential area defining an inner and outer shape of the shell. The area is marked, cropped and smoothed. It is the created area of the lower end of the patient femur respecting the overall curvature of the knee joint.
Within designing of the implant prototype of the femoral component of the knee-joint modern methods of getting CT data, their processing by CAD software called CATIA and subsequent post processing are applied.
The prototype implant of the femoral component of the knee joint is designed from processed CT data of the patient affected knee-joint (the femur distal part, a tibia proximal part). The 3D model of the implant prototype of the femoral component is created on the basis of data editing in CATIA software. The final 3D model is then located to the composition (a bone, the implant prototype) and using anchoring ribs it is fixed on the femur distal part.