E-learning environment integration in the chemical engineering educational processMajda Krajnc
, 2009, original scientific article
Abstract: This paper introduces the electronic Portal, reports on the experiences of its use, shows how it motivates students towards more successful study, encourages lecturers to give better lectures, enhances learning, and so reduces workloads. A group of students from the Department of Chemistry and Chemical Engineering in Maribor have used this Portal in their Process Synthesis Course for the last four years. Their responses to e-learning and the Portal were collected by means of a questionnaire. The students thought that the Portal was an effective tool that helped them to improve the quality and efficiency of their studies. They thought a combination of lectures and elearning to be the most suitable solution for them because it gives a freedom of choice in methods and time devoted to studying. They suggest that this kind of arrangement would be beneficial for use in the future. These statements could motivate college students to choose studies at departments that use modern technologies within the educational process and thus increase the enrolment in those departments. The faculties' responses to using the Portal are also presented. The results of their questionnaires were not as encouraging as the students'. A few lecturers had already used certain functions of the Portal but, in general, they thought that the incorporation of e-learning into the educational process means a heavier workload and is time-consuming. Perhaps the experiences of the lecturer for the Process Synthesis Course, who has been using e-learning for several years, will demonstrate that the incorporation of e-learning into the educational process leads to a heavier workload at the start, but this reduces over time. Perhaps this experience will encourage the faculty to reconsider.
Keywords: ICT, electronic tool, e-learning, chemical engineering courses
Published: 31.05.2012; Views: 1089; Downloads: 18
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Intelligent programming of CNC turning operations using genetic algorithmJože Balič
, Miha Kovačič
, Boštjan Vaupotič
, 2006, original scientific article
Abstract: CAD/CAM systems are nowadays tightly connected to ensure that CAD data can be used for optimal tool path determination and generation of CNC programs for machine tools. The aim of our research is the design of a computer-aided, intelligent and genetic algorithm(GA) based programming system for CNC cutting tools selection, tool sequences planning and optimisation of cutting conditions. The first step is geometrical feature recognition and classification. On the basis of recognised features the module for GA-based determination of technological data determine cutting tools, cutting parameters (according to work piece material and cutting tool material) and detailed tool sequence planning. Material, which will be removed, is split into several cuts, each consisting of a number of basic tool movements. In thenext step, GA operations such as reproduction, crossover and mutation are applied. The process of GA-based optimisation runs in cycles in which new generations of individuals are created with increased average fitness of a population. During the evaluation of calculated results (generated NC programmes) several rules and constraints like rapid and cutting tool movement, collision, clamping and minimum machining time, which represent the fitness function, were taken into account. A case study was made for the turning operation of a rotational part. The results show that the GA-based programming has a higher efficiency. The total machining time was reduced by 16%. The demand for a high skilled worker on CAD/CAM systems and CNC machine tools was also reduced.
Keywords: CNC programming, genetic algorithm, intelligent CAM, turning, tool path generation
Published: 30.05.2012; Views: 1364; Downloads: 61
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Intelligent cutting tool condition monitoring in millingUroš Župerl
, Franc Čuš
, Jože Balič
, 2011, original scientific article
Abstract: Purpose: of this paper is to present a tool condition monitoring (TCM) system that can detect tool breakage in real time by using a combination of neural decision system, ANFIS tool wear estimator and machining error compensation module. Design/methodology/approach: The principal presumption was that the force signals contain the most useful information for determining the tool condition. Therefore, ANFIS method is used to extract the features of tool states from cutting force signals. The trained ANFIS model of tool wear is then merged with a neural network for identifying tool wear condition (fresh, worn). Findings: The overall machining error is predicted with very high accuracy by using the deflection module and a large percentage of it is eliminated through the proposed error compensation process. Research limitations/implications: This study also briefly presents a compensation method in milling in order to take into account tool deflection during cutting condition optimization or tool-path generation. The results indicate that surface errors due to tool deflections can be reduced by 65-78%. Practical implications: The fundamental limitation of research was to develop a single-sensor monitoring system, reliable as commercially available system, but much cheaper than multi-sensor approach. Originality/value: A neural network is used in TCM as a decision making system to discriminate different malfunction states from measured signals.
Keywords: tool condition monitoring, TCM, wear, tool deflection, ANFIS, neural network, end-milling
Published: 01.06.2012; Views: 876; Downloads: 20
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Prediction of total manufacturing costs for stamping tool on the basis of CAD-model of finished productMirko Ficko
, Igor Drstvenšek
, Miran Brezočnik
, Jože Balič
, Boštjan Vaupotič
, 2005, original scientific article
Abstract: One of the orientations of the tool-making industry is towards shortening the time from enquiry to the supply of tools. The tool-making shops must prepare within the shortest possible time an offer for the manufacturer of the tool based on the enquiry in the form of the CAD-model of the final product. For preparation of a proper offer, the values of certain technological features occurring in the manufacture of the tool are needed. Most frequently the tool manufacturer is interested in total cost for manufacture of the tool. Because of lack of time for making a detailed analysis the total costs of tool manufacture are predicted by the expert on the basis of the experience gathered during several years of work in this area. In our work, we conceived an intelligent system for predicting of total cost of the tool manufacture. We limited ourselves to tools for manufacture of sheet metal products by stamping; the system is based on the concept of case-based reasoning. On the basis of target and source cases, the system prepares the prediction of costs.The target case is the CAD-model in whose costs we are interested, whereas the source cases are the CAD-model of products, for which the tools had already been made, and the relevant total costs are known. The system first abstracts from CAD-models the geometrical features, and then it calculates the similarities between the source cases and target case. Then the most similar cases are used for preparation of prediction by genetic programming method. The genetic programming method provides the model connecting the individual geometrical features with total costs searched for. In the experimental work, we made a system adapted for predicting of tool costs used for tool manufacture on the basis of a theoretic model. The results show that the quality of predictions made by the intelligent system is comparable to the quality assured by the experienced expert.
Keywords: intelligent systems, prediction of costs, tool-making, stamping, CAD model, costs, genetic programming
Published: 01.06.2012; Views: 1098; Downloads: 58
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Databases for technological information systemsFranc Čuš
, Bogomir Muršec
, 2004, original scientific article
Abstract: Organization of tool management for mixed production includes today, in particular, the computer-supported management and organization of the flow of tools and data on them. The system supports the entire flow of tools in a production process including the tool store management, commissioning, mounting, dismantling and pre-setting of tools. The system contains the management of the tool database with all vital data on tools and ensures adaption of production requirements for meeting the needs for tools. The integral model for the selection of optimal cutting conditions in the computer aided tool management system (TOMS) is proposed. The integration of technological databases and tool management systems is urgently necessary. The target function for the OPTIS programme, worked out by the programme package Microsoft Visual Basic, is selection of optimal cutting conditions from commercial databases with respect to the lowest costs of machining by taking into account the technological limitations of the metal removal process. The newly developed OPTIS programme selects optimal cutting conditions with respect to the tool maker, workpiece material, type of machining, cutting machine, smallest and greatest cutting conditions, tool, data on series, type of clamping and workpiece geometry.
Keywords: machining processes, tool system, manufacturing systems, technological information systems, databases, tool management, machining systems, cutting conditions
Published: 01.06.2012; Views: 1104; Downloads: 57
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Open-source software in medical imaging: case-based study with interdisciplinary innovative product designGregor Harih
, Andrej Čretnik
, 2012, original scientific article
Abstract: Namen: V zadnjem času je bilo razvitih precej celovitih rešitev odprtokodne programske opreme za medicinske slike, ki ponujajo zmogljiva orodja za slikovno upravljanje, vizualizacijo, skladiščenje in analizo. Namen članka je predstaviti odprtokodno programsko opremo za delo z medicinskimi slikami in njene značilnosti ter jo primerjati s komercialnimi rešitvami. Metode: Predstavljen je primer razvoja optimalne velikosti in oblike ročaja ročnega orodja s pomočjo brezplačne odprtokodne programske opreme '3D Slicer'. Večina avtorjev priporoča valjasto oblikovanost ročajev, da bi povečali udobje in učinkovitost uporabnika ter preprečili kumulativna travmatična obolenja, vendar optimalna oblika ročaja še ni bila ugotovljena. Namen raziskaveje predstaviti metode, s katerimi je mogoče pridobiti obliko ročaja v optimalni drži roke za krepki oprijem s čim bolj optimalno porazdelitvijo pritiska na mehka tkiva. Uporabili smo magnetno resonančno preiskavo in individualno izdelan kalup, ki je ohranjal optimalno držo roke med preiskavo. Program '3D Slicer' je bil uporabljen za segmentacijo in 3D rekonstrukcijo na osnovi MR slik. 3D model roke je bil nato 'izvožen' v komercialni program za računalniško podprto konstruiranje optimalnega ročaja orodja. Rezultati: Meritve premerov na 3D rekonstrukciji so pokazale, da so bili položaji zadržani z le majhnimi odstopanji, kar maksimizira največjo silo kontrakcije prstov. Tako oblikovan optimalni ročaj zagotavlja 25 % večjo kontaktno površino v primerjavi z optimalnim valjastim ročajem in s tem zmanjšuje tudi kontaktne tlake, kar povečuje učinkovitost in udobje ter (zelo verjetno) preprečuje kumulativna travmatična obolenja. Zaključki: Prikazan primer potrjuje ustreznost odprtokodne programske opreme za medicinske slike kot (večinoma) brezplačno in učinkovito orodje, podobno kot (neredko drage) druge komercialne rešitve.
Keywords: tool handle, software, open source, ergonomics, segmentation, medical imaging, hand model, 3D
Published: 10.07.2015; Views: 661; Downloads: 18
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