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In 1906 Taylor mathematically defined the dependance of tool durability on cutting speed in the form: T=CT/vm for the first time. It is an equation of a hyperbola, which represents itself as a straight line in double logarithmic net according to Taylor. The dependance is valid for the tools made of high-speed steel. It has still been used in spite of the fact that new cutting materials, which cannot be used according to it, or can be used only partially in a narrow range of higher cutting speeds. The course of function T=f(vc) for the tools made of sintered carbid and ceramics will be identified in the paper. It requires extensive durability tests in a wide range of cutting speed. Interesting conclusions can be derived from its course.

In micro cutting it is necessary to control the cutting tool. Monitoring of cutting tools is usually accomplished by measuring cutting forces. In order to improve the accuracy of monitoring it is required to consider the ploughing forces. The ploughing forces substantially depend on the processing materials. This article describes the investigation of the effect of processing materials on the ploughing force values. The extrapolation method on zero cut chip thickness was used to determine the ploughing forces. The experiments were performed by cutting of aluminum alloys, structural steels, bronzes and stainless steels.

During turning, in the course of the deformation of the material, a metallic deposit, a so-called built-up edge (BUE), may occasionally form, which may damage the surface and shorten the tool life. We have observed the effect thereof on chip formation using microscopic techniques and have developed a mathematical model for this process. Laboratory experience confirms the numeric solution of the time-delayed autonomous differential equations. This model can be applied to other technologies as well where the thickness of the undeformed chip varies.

Magnesium based alloys are light-weight materials having a good strength to weight ratio making them of interest for many structural applications in automotive and aerospace industry. Besides, magnesium is also considered as promising metal for construction of temporary biodegradable medical implants like stents or fixation devices for fractured bones. A biodegradable implant progressively corrodes in the human body fluids and is replaced by the healing tissue. No second surgery is needed to remove the implant after the bone has healed. The advantage of magnesium is that it is relatively non-toxic metal and that its mechanical characteristics (strength, Young's modulus) are close to those of natural bone. But pure magnesium is not very suitable, because it has a low strength and too high corrosion rate in comparison with the rate of bone tissue healing. Therefore, a great effort has been devoted to find suitable magnesium based alloys which possess sufficient strength levels and low corrosion rates in the human body. This paper presents structural, mechanical and corrosion properties of magnesium based alloys containing zinc, rare earth metals and zirconium as the main alloying elements.

The traditional approach to grinding is to operate within the limits of surface quality. The requirements for surface quality in grinding are higher than those in other common machining operations such as turning and milling. The surface quality of machined parts is very important for precise production and assembly. When we focus on roughness parameters after grinding, we can establish the limits of these parameters for typical grain materials: Al2O3, SiC, CBN, SG and others. Increasing demands on accuracy and quality of production leads to research concerned with the properties of these materials and the surface quality after grinding. This paper shows new possibilities for the ground surface with focus on surface roughness obtained under varying combinations of cutting conditions. The influence of the grinding wheel, cutting parameters and coolant on higher surface quality is assessed by roughness parameters Ra, Rz, Rt and the Material portion of a surface profile. These high-precision ground surfaces are shown to have a Nanometres (10-9) unit topography demonstrating that the process is able to replace other finishing technologies such as superfinishing or honing.

The aim of the performed works was research on the causes of formed aluminum blanks cracking in the range of the AlCuSnBi alloy rods where cracks appear during mechanical machining (turning, drilling) of this range to the final part. AlCuSnBi alloy was invented as a substitute for aluminum machining alloys Al - Cu type alloyed with lead. For the alloy were performed qualitative and quantitative fractographic analysis of the fracture surface after machining in order to determine possible causes cracking of the material and thus his lack of strength during machining. Part of this paper is to the overall theoretical analysis of the issue. This paper clearly documents that fractographic analysis methods can significantly and to the extent required to provide answers to the causes of insufficient material strength during machining. Also points out the possible causes of cracks in this alloy during machining and ways to eliminate them.

Hot-dip galvanizing is one of the most widely used method for protecting of structural steels against corrosion. In general galvanizing process dross called as "hard zinc" is formed on the bottom of the zinc bath. It is formed by the reactions between molten zinc and iron particles in the galvanizing kettle. Hard zinc represents valuable secondary raw material because of the high content of metallic zinc (94-97%). Bottom dross, being an alloy of zinc and intermetallic phase crystals containing 3-6% wt. Fe, has no direct use in the galvanizing process. For this reason there are attempts to elaborate the technology of obtaining a refined zinc containing less then 0,05% wt. Fe. Hard zinc refining with aluminium is one of the method for iron removing. Refining process is based on the formation of intermetallic particles of AlxFey type. Refining of hard zinc through removal of iron has been investigated in this study. The effect of various aluminium additions as a refining agent has been studied. Light microscopy and AAS (Atomic absorption spectroscopy) have been used in the evaluation of the refining process.

A paper deals with technological applications of laser. It evaluates the influence of design and technological conditions on output parameters of cutting process and also presents relative laser machinability of polymeric and metallic materials; in addition, it shows possible evaluation of structural change of metals and it gives mathematical model for determination laser cutting quality functions based on results of the experimental research. The temperature distribution has been derived. Results of plastic materials and hard-to-machining metals machinability are shown. Finally, surface quality evaluation after exposure to concentrated light energy and quantification of material microhardness are described.

Frequent consumption of certain products contained the different kinds of chemical compounds affects on the colour of teeth, especially on prosthetic restoration timbre. A very interesting issue is to determine the effect of exposure in some of the commonly used chemical substances on dental restorations colour change. The study was conducted on the upper crown of the tooth, namely the first incisor. The colour evaluation change has been made using a spectrophotometer SpectroShade, which determines the amount of light absorbed by the element over the entire visible spectrum 380 - 720 nm. In the paper was shown that long-term use of products that contain chlorhexidine can lead to permanent color change of ceramics dental materials. After long exposure in the solution the ceramic became lighter but their hue value indicates that the color is closer to yellow.

During the operation of manufacturing systems with hydroabrasive jet technology, arising in the production system vibrations, which affeon ct its reliability and durability, operating costs and consequently economic efficiency and operational safety. The emergence and spread of vibrations generated by water jet technology remains actual and theoretically difficult issue, which is currently not sufficiently developed. Despite the best efforts of researchers and a good knowledge of the operation in PS with water jet technology remains unexplained facts. One of them is the abrasive mass flow technological parameter affecting the acceleration amplitude and vibrations frequency on technological head, which is the subject of experimental investigation during cutting steel abrasion resistant HARDOX 500.

The solution and evaluation of the production system (PS) operation with water jet technology was addressed in more works. It is appropriate to complement this knowledge from works focused on investigation of the other factors effect which affecting the emergence and spread of technological head vibrations, affecting reliability, durability, economic efficiency and operation safe of PS with water jet technology. The article presents experimental investigation results of the vibration acceleration frequency spectrums during cutting steel by unwear and wear rectifying tube with water jet technology. The vibrations size was assessed by two basic vibrations parameters - vibrations frequency and vibration acceleration amplitude.

Nano-crystalline metals with structural constituents smaller than 100 nm are prospective materials due to very high hardness and strength, high specific surface, chemical catalytic activity, high gas absorption capability and other characteristics. They can be produced by various methods like precipitation from liquids, vapor deposition techniques, intensive plastic deformation, rapid solidification etc. These methods enable obtaining materials of a wide range of crystallite size. The selective leaching of appropriate alloys is another method to prepare nano-crystalline metallic powders (Fe, Co, Cu, Ni etc.) with high specific surfaces. So far, these powders have been studied mainly for catalytic or magnetic purposes. But we illustrate in the present study that these powders can be successfully applied also in the development of bulk materials with a high hardness and strength (Cu) and of media with excellent hydrogen storage capacity (Ni).

In paper are presented basic characteristics and problems in area of Rapid Prototyping technology with use of layered production technology named Fused Deposition Modelling (FDM). It is progressive method of 3D model product creation based on geometry obtained from CAD system with application in different industrial areas. Text of the paper is focused on optimization of Rapid Prototyping preparation process. There also is algorithm that leads to selection of suitable setting conditions. Utilization of algorithm is explained on case of printing with use of UPrint device and Catalyst software. There are outputs in form of graph and tables accumulating information directly affecting economical and quality aspects of Rapid Prototyping production technology.

This article deals with dry turning of nickel superalloy - Inconel 718. The different ceramic inserts were applied for cutting process. These inserts were produced by Greenleaf Corporation company. This paper discusses durability of cutting inserts, the different intensity of tool wear at various cutting parameters. The most suitable cutting conditions are chosen in the scope of applied tools.

Experiments described in this paper determine two body abrasion of two- and three-phase polymeric particle composites with a different size of filler particles. An epoxy resin was the matrix of composite systems, corundum and chips of iron metals represented the filler created from secondary raw materials. The results show clear influencing of composite hardness and abrasive wear resistance caused by the fillers. The influence of the size of bonded abrasive particles on the wear of the composites based on the waste was proved and it is noticeable - with tested abrasive clothes it is 65 times.

Machinery maintenance significantly participates in its reliable, serviceable and safe operation. Well-timed maintenance can identify a fault condition of machinery leading to manufacturing a product of poor quality. Maintenance interval can be fixed or maintenance can be done when needed, meaning at the moment when some of operating parameters get worse. An example of determination of diagnostics interval set based on machinery vibrodiagnostic measurement is described in the paper. The shown steps are universal and can be applied to another technical diagnostics methods as for example tribodiagnostics, thermodiagnostics, non-destructive materiology etc.. This way economic savings can be reached better comparing to maintenance done in fixed planned dates.

When selecting the optional parameters in machining inner cylindrical surfaces the diameter of a borehole cannot be ignored. Also in finish precision machining, when fulfilling strict accuracy and surface quality parameters economically, it was presumed that the size of the borehole diameter has got an effect on the machining times of different procedures. Five different hard machining methods are compared here on the basis of time consumption. The common characteristic feature of the comparative investigations of different hard machining procedures is that their benchmark is always the traditional grinding. This time, too, that has been chosen. It is presented how the borehole diameter influences the machining times and the most economical procedure is proposed to be selected for given borehole diameter.

This paper presents some analysis of color metallography in the identification new structures of aluminium alloys. For experimental purposes aluminium alloy from the group hypereutectic AlSi7Mg 0,3 silumins was used. Alloy and modified using calcium in the form of master alloy AlCa10. The master alloy AlCa10 in the analyzed alloys added to improve the technological properties af alumium alloys, especially fluidity and machinability while maintaining sufficient corrosion resistance of the alloy. The analysis and evaluation of individual structural components are used method of color etching. The analyzed alloy was also subjected to the method of the black and with contrast what, but not of this paper subject. The application of color metallography is possible to differentiate and identify the presence of the intermetallic particles with different chemical composition.

The article deals with the automation of the grinding machine duty cycle. There are both described, the problems of the automation of the duty cycle and the present state summarised in this paper. The control systems of grinding cycle run from the experiences and process knowledge. Real GICS (Grinding Intelligent Control System) must be founded on the process monitoring and to create own control system with principal parameters of grinding. Cutting speed, workpiece motion speed, depth of cut, volume of coolant, course of cutting forces and other process parameters can form single control components at the adequate process knowledge. At some control systems description the authors assume the future possible direction of development, considering possibilities in the use of the expert and intelligent systems.

In this paper, we deal with the topic of production of precise wax patterns for investment casting technology. We focus on the issue of scanning thermal image arrays when measured object (wax blade model) has a temperature very close to ambient temperature. It is shown on specific examples how to filter disruptive thermal reflections that enter thermal array scanning on almost perfectly reflexive body. Based on verification of this measurement using the touch probe thermometer, this paper deals with the thermal influence of wax models in various stages of production. The biggest influence on stability of wax models occurred on workplace that carries out bonding of wax models into trees, where they use heat source for bonding, which in a moment can affect the temperature of the wax model so that its temperature is above the critical 30°C. The possibility of shielding of radiant heat, which significantly affects the shape of the wax model is also pointed out in this paper.

The effect of microstructural banding (or so called segregation bands) on energy absorption capacity of dual-phase steels (DP steels) was examined by product of tensile strength and uniform elongation (TS×UE), as well as by Charpy V-notch impact test. A series of DP steels with different volume fractions of martensite (VFM) was prepared by intercritical annealing at temperatures ranging 740 to 840 °C. It was found that increasing of VFM has an inverse effect on values TS×UE and notch toughness. The results on samples with a notch and pre-cycled crack showed that presence of segregation bands influences capacity of steels to absorb the energy in initial stage as well as in stage of crack propagation.

In the course of homogenizing annealing of aluminium alloys being cast continually or semi-continually it appears that chemical in homogeneity takes off within separate dendritic cells (crystal segregation). It is about a diffusional process that takes place at the temperature which approaches the liquid temperature of the material. In that process the transition of soluble intermetallic compounds and eutectic to solid solution occurs and it suppresses crystal segregation significantly. Temperature, homogenization time, the size of dendritic cells and diffusion length influence homogenizing process. The article explores the optimization of homogenizing process in terms of its time and homogenizing annealing temperature which influence mechanical properties of AlZn5,5Mg2,5Cu1,5 alloy.

In paper are presented basic information about common and progressive materials used for realization of products by Rapid Prototyping technology application. The initial state of material can come in either solid, liquid or powder state. In solid state it can come in various forms such as pellets, wire or laminates. The current range materials include paper, nylon, wax, resins, metals and ceramics. Last mentioned materials are used manly in application of Rapid Prototyping technology for rapid manufacturing of products or rapid production of tools - Rapid Tooling.

This article provides perspective into creation of virtual 3D models of manufacturing devices and optimization of existing machine tools by using an alternative scanning device and freeware software applications (open source elements). This alternative offers scans of components surfaces that are from the viewpoint of precision and quality comparable with much more expensive devices. Various parts of the paper describe the process of creation of the environment with the use of Kinect scanner device and various software tools. At the end an additional options are provided for using with sensing device.

Composites are materials which combine properties of two and more phases and create entirely new material. In case of the polymeric particle composites one phase - a matrix is represented by the polymeric material most often in a form of an epoxy resin and the second phase - a filler is composed of inorganic particles. The paper deals with the polymeric particle composites whose matrix is composed of the epoxy and polyester resin with a high concentration of a waste corundum (Al2O3) particles. The paper focuses on chosen mechanical qualities of these materials: an abrasive wear resistance and an impact strength. Increased portion of the filler in the matrix predetermines these systems to considerable abrasive wear resistance. This hypothesis was confirmed by carried out experiments when the volume loss decrease of the composite systems with the matrix saturated with the particle filler reached values 0.04 cm3 whereas the volume decrease loss of the epoxy resin without the filler reached 0.56 cm3. The maximum applied saturation of the matrix with the particle filler was reached at the polyester resin when this value corresponded to 50 volume percentages.

The aim of the work was carried out research on the causes cracking formed aluminum work pieces in the assortment of rods, which sometimes occur in the mechanical machining (turning, drilling) for alloys of Al-Cu. A typical representative for the machining of aluminum alloys is AlCu4MgMnPb alloy, most of which performs heat treatment for hardening increases the ultimate strength. For the given alloy were carried out qualitative and quantitative fractographic analysis of fracture surfaces after machining in order to determine possible causes cracking of the material and thus his insufficient strength. This paper clearly documented that the fractographic analysis methods can clearly and in the extent required to provide answers to the causes of insufficient strength of the material when cutting. At the same time points out the possible causes of cracks in this alloy in machining and ways for their elimination.

Introduction into problems - The aim of the paper was microscopically analyze protective layer by coated sheets after corrosion loading which were pre-treated by various ways. The samples were divided into 4 groups according to the pretreatment type and duration of corrosion load. After a corrosive effect on the corrosion chamber the protective layer was subjected to microscopic evaluation. For samples of group I and IV have to degrade the protective layer and the formation of corrosion products on the base material which causes degradation of the protective layer and shorten its life. For samples of group II and III microstructural analysis showed good condition of the painted surface layer and the base material showed no presence of corrosion products. It again confirms the need for compliance of technological conditions for the pretreatment of the surface particularly in the application of modern less aggressive means.

An investigation was carried out through a study of the influence of material anisotropy and geometrical parameters of the cylindrical plastic parts reinforced by short fibres, on the state of stress. It has been shown that the result of such injection-moulded processes is an anisotropic product, whose mechanical behaviour differs considerably for that of classical types of isotropic solids. Unlike unreinforced plastics, fibre composites exhibit different stress phenomena and mechanical properties notably in cases where composite parts are highly curved. These unusual effects of their mechanical properties thus need to be considered carefully in the course of designing of reinforced plastic parts.

This contribution deals with the need of continual experimental study of the phenomenon that relates to the increasing demands to the quality of engineering production and also to the productivity and economy of the production. Experimental part is focused to the influence of the tool coatings, which significantly affect the roughness of the material machined with the use of the cutting plates made of high-speed cutting steel. The plates were used in the series of the experiments, what allows us to create the models of real situations in the area of concrete manufacturing technology and subsequently to analyze them. To the measured and evaluated parameters belonged: the roughness of the machined material after the use of coated and uncoated tools. Planing technology is realized until there are major visible changes in cross roughness of the machined material, what means the increasing of Rz values. This is caused by the fact, that the coating was removed from the cutting edge, what is considered as the blunting of the tool. Measured values are statistically expressed in the form of the graphs.

The article presents problems with commercial inverter source Rapid Arc application on fillet and V-grooved welds. Principal and conditions of the process are explained and especially restriction due to source and feeder upper power limit is described. Case study of "weld design for fabrication" method was demonstrated, where type of weld and shape of groove is designed on the base of experimental results of process penetration behavior at 1/2 V-groove joint. Results are described and discussed, using special welding parameters monitoring equipment and software. A change of metal transfer behavior was recorded in accordance with torch angle setting and originally explained.