Key Engineering Materials Vol. 669

Abstract: The article presents the results of Technical University in Košice Faculty of Manufacturing Technologies Department of production processes operation and Technical University in Ostrava Physics Institute Liquid jet workplace cooperation in the area of operational states diagnosis of manufacturing systems with abrasive water jet technology (AWJ). Within the operational states diagnostics is the impact of selected technological parameters on technological head vibrations studied. Based on an extensive set of experiments are original graphical dependences determined of the abrasive mass flow and feed speed impact on the vibrations parameter - technological head vibrations acceleration amplitude of manufacturing system with AWJ technology. In addition to the original graphical dependences are in article new knowledge formulated in the area of science and research and recommendations for companies that operates manufacturing systems with AWJ technology.

Abstract: The modern world of mechanical and electrical engineering disposes of a very high amount of appliances and devices for measuring the values of various parametres. When designing a device for measuring the deflection of a roller in a two cylinder bending machine, the measured parameter of the deflection can deviate by several dozen micrometres either side of zero. Therefore, it is necessary to design a measuring appliance or device with the sensitivity to measure this error of measurement within these limits. Similarly, we have to consider the fact that the device of the bending machine is already produced as an individual machine and the design of the device for measuring the deflection will be part of its superstructure.

Abstract: The moment of formation and spread of cracks on the surface of metal mould cavity is rather significant in the sphere of die casting due to durability of these costly tools and especially in case of casting of metals and alloys with higher melting temperature. The issue examination requires analysis of the thermal aspect of the process and of the mechanism of mechanical stress occurrence of material.For the purpose of verification of occurrence and spread of cracks the fragile materials were firstly tested in case of which inevitable number of cycles was possible to be considered acceptable for testing performance. The first tests were accompanied by the ring dipping with diameter of 60 mm with the central hole with diameter of 15 mm from alloy according STN 42 2420 standard, i.e. with dimensions reaching the used mould filler into molten salt at temperature of 1000°C for the period of 30 s with following dipping into water (20°C). The sample surface checking was performed visually after every 100 cycles.To make a comparison the dependence of length of cracks with circular samples with diameter of 12.7 mm made of material H11, H13, H21 and of steel Maraging.

Abstract: The article deals with the correction of the programmed path lathe tool with a tip radius size. This correction is required to use in turning shaped surfaces. The programmed tool path can be corrected in various ways. In the first case, the calculation of the correction applied through mathematical relationships. The latter was used for automatic correction by the preparatory functions. Subsequently, the manufactured parts are measured, compared and evaluated characteristics shaped surfaces. Based on the evaluation method was recommended correction tool tip for the production of shaped surfaces.

Abstract: Essential factors of each new discovery or piece of knowledge in science are predetermined, prepared and realized experiment. Every successfully realized experiment with obtained outputs and measurements indicates the gauge of asset that has been achieved by its execution. After analyzing of outputs final dependencies can be described that generalize whole experiment and allow entire process to be analytically identified. The production of bearings is very difficult process. Especially production of bearing rings is very complicated. Optimization of this process means significant savings for the company. Bearing rings are produced by turning. One of the most important parts of the turning process is cutting tool. On the base of cutting tools are determined many factors for example: quality, price, cutting speed, etc. All these factors of cutting tools are the only consequence of these cutting tools durability. Cutting tool durability determines its cutting properties and machinable ability. Specification of tool wear by means of calculation is very difficult. Durability of cutting tools is defined in standard ISO 3685. In standard ISO 3685 is defined T-v_c dependence for different cutting materials and standard included process evaluation of tool durability for cutting materials made of high speed steel, sintered carbide and cutting ceramic. The article describes evaluation of T-v_c dependence on the selected type of cutting materials and theirs comparison with measured values T-vc dependence that are defined in standard ISO 3685.

Abstract: Specification cutting tools durability made of cutting ceramic in machining process of steel 80MoCrV4016 is very important for economics of small and medium-sized enterprises, because cutting tool durability is factor that significantly affects the budget of these enterprises. This problematic is determined for small and medium-sized manufacturers of bearings, because steel 80MoCrV4016 is most commonly used for production of bearings. Durability of cutting tool defines lifetime of this cutting tool and it determines its suitability for select technological operation. Especially for cutting ceramic is necessary to define durability dependence on available set of cutting speeds and to determine lifetime of tools made of cutting ceramic. Technical science defines a lot of different factors, that they may be cause of shorter cutting tool lifetime. For increase cutting tool durability is necessary maximally possible elimination of these factors. Determination of cutting tool durability is very important, because provides comprehensive information how to determine appropriate technological conditions for selected cutting tool. In engineering is for determination of cutting tools durability used T-v_c dependence. The article describes process how to create durability dependence for cutting tools made of cutting ceramic by means of T-v_c dependence in machining process of steel 80MoCrV4016.

Abstract: Precision machining is currently intensively studied. Production of quality products fast, and precise with paying attention on environmental issues, brings many factors which counteracts to ensure these aspects. Is very crucial to know system machine – tool – workpiece and is necessary to characterize all elements and limitations connected with this system. Choice of suitable cutting tools is very important part of production process. Acquisition cost of tools in serial production is only below 10 % but in medium production can be up to 50 % of production cost. Know the characteristic of the tool is very important to ensure effective machining process and economic stability of whole production process. The article is focused on clarification of basic indicators, which should be used to more effective and more economical handling with cutting tools.

Abstract: Technology of Electrical Discharge Machining (EDM) uses thermal energy in material removal, in which is the electrical energy transformed, generated between the electrodes (tool and workpiece). The material removal occurs through the rapid periodic repetitive electrical discharges in the presence of dielectric fluid. By the action of electrical discharges occurs to decline not only particles of a metal workpiece material, but also to decline in a certain proportion of metal particles in tool electrode. The paper deals with the diagnosis the size of the electrode wear of tools made from copper and graphite used in EDM machining.

Abstract: The main part of Standard ISO 3685 is T-v_c dependence for various cutting materials. The Standard ISO 3685 contains main properties and characteristics for three most important cutting materials those are used in engineering practice. Durability is very important property of every cutting material. This property of cutting materials defined theirs life-time. The standard ISO 3685 prescribes instructions to creation of T-v_c dependence for defined cutting materials. Paper describes process how to define T-v_c dependence for the most commonly used, because were found deficiencies in valid standard ISO 3685.

Abstract: Durability of cutting tools consists form several partial sections. Determination of durability for each specific turning knife, milling head or cutting insert is very complicated. Wide spectrum of factors affects durability of cutting tools, which is important to study and analyze to point out the differences in this process. Major factor influencing cutting process is technological system, which consists of machine, toll, work piece and cutting conditions. In addition to used cutting material there are more parameters affecting cutting process. Properly selected cutting conditions and coating of cutting tool can accelerate production process, improve quality of products or vice versa economically disadvantages. Article deal with analyze of durability of selected cutting materials and compares results of experiment with F.W. Taylor rules and standard ISO 3685. Article highlights on differences developed due to different technological systems in turning process of steel C60. The article also describes process how to define and analytically express T-v_c dependence.