Advanced Materials Research Vol. 801

Abstract: This paper presents the effect of three oil types on the quality of hydraulic pumps after testing on a special test bench. The quality of material of hydraulic pump components was evaluated on the basis of its wear. In the special test bench, hydraulic pumps were loaded by cyclic pressure with different oil types. There were tested a mineral oil-based liquid HV and two biodegradable types, i.e. a vegetable oil-based liquid HETG and polyalphaolefin oil-based liquid HEPR. The wear level of hydraulic pumps was evaluated on the basis of flow efficiency and the weight and roughness of internal components. Laboratory scales were used to measure the weight of hydraulic pump components. Results of measured roughness and weights ​​have been graphically compared. We noticed the most significant material wear on bearings and slide plates. The highest loss of weight was observed in the hydraulic pump tested with the ecological oil HETG. The highest loss of flow efficiency (7.3 %) was measured with the same oil type. This paper shows differences in the wear of hydraulic pumps after testing with different types of oils on the basis of selected methods of technical diagnostics.

Abstract: This paper deals with the lifetime test of a tractor hydraulic pump. The basic indicator of hydraulic pump lifetime is flow characteristics. This paper presents the results of the performance test of ecological hydraulic fluid. These results were subjected to statistical analysis. Based on these data, it is possible to express a minimum impact of ecological hydraulic fluid on hydraulic pump lifetime. The test was carried out in cooperation between the Department of Transport and Handling (Slovak University of Agriculture in Nitra) and Slovnaft, a.s. (joint-stock company), and supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic – VEGA, ref. No 1/0857/12.

Abstract: The goal of the presented contribution is a comparison of two variants of differential mechanical planetary gearboxes. The designed variants of differential gearboxes are characterized by gear shifting under load. Reflected depending on the variable gear may be a change of gear ratios, either stepped or continuously. The results of kinematic analyses of both variants of differential planetary gearbox with differential in output are shown in tabular and graphical form

Abstract: This research deals with the corrosion stability of components with a galvanized surface. The aim is to determine how corrosion resistance is influenced by chemical degreasing. The ZiNi galvanizing method in a bath line was performed on 10 components; another 10 pieces were treated by the same galvanizing method, but without previous chemical degreasing. After measuring the thickness of coating, components were inserted into a salt spray corrosion chamber. The test showed that components with a complete galvanizing process revealed no signs of red corrosion after 456 test hours. In components without chemical degreasing, there were signs of red corrosion after 200 test hours. After this research, we can conclude that chemical degreasing in galvanizing processes has a high influence on corrosion resistance.

Abstract: This contribution focuses on solving a customer complaint accepted by an organization for manufacturing of automobile seats. The occurrence of nonconformity and causes of undetected nonconformity in the manufacturing process of automobile seats is solved by seven new quality management tools. Causes, effects, activities leading to elimination of the problem, remedies and precautions for possible problems within solution implementation, and time schedule with individual reserves are defined. Results lead to solving the issue both on the part of supplier and on the part of the organization for manufacturing of automobile seats

Abstract: Thermal spraying influences several physical and chemical properties of the coating surface. The most important of them are hardness, density, porosity, corrosion resistance and adhesion. This technology of surface treatment of material is often used for its high degree of hardness. Hardness and erosion resistance are the parameters that need to be achieved particularly in working conditions where there is excessive component wear. In this paper, we deal with the impact of purifying on the quality of molybdenum layer. Insufficient cleaning may result in a poor quality of the sprayed layer. Our aim is to measure and analyse the quality of molybdenum layer thickness applied by thermal spraying after insufficient cleaning.

Abstract: The aim of this article is the introduction of statistical control in the manufacturing process of Ribe Slovakia, k.s. (limited partnership) in Nitra, Slovak Republic, which consists of determining the capability of production equipment. The chosen production equipment is a multistage forming press SACMA SP 260, which was used in the process of cold forming when manufacturing screws of type WZ 13 340 intended for engine blocks. Determining the capability of production equipment involves removing 50 consecutive products, identification and evaluation of stability (construction of card and card), determination of normality (construction of frequency distribution series, histogram and cumulative relative frequency curve), and calculation of capability indices of production equipment C_m and C_mk.

Abstract: This contribution focuses on hole drilling into grey cast iron and steel 11 523. The most used method of hole machining is the one using a screw drill HSS to reach the accuracy class from IT 11 up to IT 14. Surface roughness ranging between R_a 3.2 μm and R_a 6.3 μm depends on the parameters of the drill used and drilled material. An emphasis is put on the accuracy of shape and dimension as well as on meeting the tolerance limits of holes [1,2,3,4,5]. In most cases, it is possible to reach those conditions using the common methods of hole drilling. Finishing such as roughing, reaming and countersinking is used for meeting high-quality requirements [6,7,8,9].

Abstract: This article analyses the optimization of technological and machining parameters when processing thermosets. These parameters were optimized by various tests, e.g. cooking and pressure test. The reason for using the cooking test is that thermosets are low molecular weight compounds and this test provides a picture of their ability to absorb the liquid. The importance of optimizing the parameters is in the fact that after moulding of thermosets, it is not possible to melt and mould them again. Therefore, every moulded piece that does not satisfy the quality conditions is a reject and loss for the company [1,2]. The article shows limiting parameters and contains proposed optimizations for moulding in order to avoid rejects and damage to machines. The three main technological parameters of moulding are examined, namely compaction pressure, mould temperature and moulding time. The external parameter is thermoset temperature [3,4,5].