In accordance with the offer no. 20120702A "Development of a system for quality monitoring of bearings" of the company Gorenje Orodjarna, d.o.o., several conceptual solutions were proposed for the development of a mechanical system for the implementation of stress tests of bearings. The proposed concepts include drive assembly, load assembly, and measuring head. The objective of the proposed conceptual solutions was to provide simple, accurate and repeatable adjustment of the operating conditions for bearings of various types and sizes, as well as provide a high-quality signal acquisition of vibration, acoustic emission and temperature, which are generated during the operation of the loaded bearing. Based on initial measurements, vibration signals of bearings were analysed. Two basic features were extracted (logMS, kurtosis), which combined discriminate bearings in low-, medium- and high-noise. For more accurate evaluation of the proposed method, the samples with known quality should be obtained and sustainable tests carried out.
F.13 Development of new production methods and tools or processes
COBISS.SI-ID: 12832795One of the crucial activities for running a successful mold manufacturing business is project estimation. The estimation process is an early project activity which is usually handled by highly skilled, in-house experts. One of the most important parameters affecting the estimation process is the volume of manufacturing hours (VMH) to produce the mold. This article suggests how to address the problem of estimating the volume of manufacturing hours by using the support of an artificial neural network (ANN) model, and its inclusion into the expert driven project estimation process. Based on the histogram of ANN estimations the percentage of unwanted underestimations of the VMH can be estimated as well and decreased by an introduced safety factor. The developed model-based estimation enables an expert to improve project estimation by using easily obtainable input data.
F.14 Improvements to existing production methods and tools or processes
COBISS.SI-ID: 12628251The laser droplet-formation process (LDFP) is a part of the novel joining technology for forming high-temperature joints. The advantages of this technology are: good heat-input control, good control of the added material and limited local heating. A molten metal droplet is used as the basic unit for the filling material, and a determination of the process parameters for the formation of droplets with desired properties is crucial. A physical and numerical model of the process was built to allow a theoretical determination of the process parameters. The numerical model enables a simulation of the process at different sets of parameters and a genetic algorithm optimization was implemented to find the best set. To verify this general procedure for determination and optimization of the parameters, we applied it in a specific case of a nickel wire. On the basis of the numerical model of the process, laser pulses for pendant-droplet formation and droplet detachment were determined and applied in experiments. With numerically determined laser pulses pendant-droplet formation and detachment were accomplished. In most cases, the process showed a very high repeatability. The encouraging experimental verification shows that a numerical approach is a very helpful tool for a determination of the process parameters and a better understanding of the process. It significantly reduces the number of necessary experiments when the laser droplet-formation setup or the target droplet properties are changed.
F.09 Development of a new technological process or technology
COBISS.SI-ID: 1002154In the paper association rules data mining is applied in order to analyze knowledge about sweet potato (Ipomoea batatas L.) in Slovenia. The aim was to find significant and interesting relationships between the answers to questionnaires, especially regarding the knowledge about the plant, its properties and attitudes towards it. We applied methods for discovering frequent itemsets and induction of association rules, which search for objects or item values that frequently appear together and from which it is possible to infer other objects or item values. In order to reduce vast amounts of produced rules, we limited the measures of support, confidence and lift in various combinations.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 7457401A system for measuring the wall thickness of castings based on ultrasound measurements was developed for company CIMOS, d.d. The system consists of a measuring apparatus for positioning the probe around the perimeter of the product, and the algorithm for analysis of measured data. Algorithm for data analysis is based on fitting a circle in the measured data, thereby reducing the impact of error of each measurement. The results of measurements in CIMOS company show that the proposed system assures good quality of finding the minimum wall thickness of products. Therefore, the proposed monitoring system can replace the existing more expensive X-ray monitoring system.
F.13 Development of new production methods and tools or processes
COBISS.SI-ID: 13384731