Lean manufacturing effects in a Serbian confectionery companyIlija Djekic
, Dragan Zivanovic
, Sladjana Dragojlovic
, Radoslava Dragovic
, 2014, original scientific article
Abstract: Background and Purpose: The objective of this paper was to evaluate effects of implementing lean manufacturing in a Serbian confectionery production company during a period of 24 months, emphasizing observed benefits and constrains. Company ‘case study’ is a leading confectionery producer in Serbia with annual production of more than 25,000 t.
Methodology/Approach: The research method was case study. The approach in implementing lean manufacturing was structured in five phases, as follows: (i) training, (ii) analysis of lean wastes on one technological line, (iii) choice of lean tools to be implemented in the factory, (iv) implementation of lean tools in production and maintenance, (v) development of continual improvement sector and further deployment of lean tools.
Results: Lean manufacturing tools implemented in the production process were visual control and single minute exchange of dies (SMED). Maintenance process implemented 5S with total productive maintenance (TPM) and problem solving sessions being the tools implemented in both processes. During the observed period, results of these tools showed the following: visual control tables initiated 61 improvement memos out of which 39% were fully implemented; a total of 2284 minor problems had been recorded, with over 95% of issues revealed in due time; total SMED time decreased for 7.6%; 19 problem solving sessions were initiated with 58% of solving effectiveness, and the remaining converted to on-going projects. In maintenance 5S improved from 29.9 to 60.3; overall equipment effectiveness (OEE) indicator increased from 87.9% to 92.3%; mean time between failure (MTBF) increased for 16.4%. Conclusion: As a result of all activities, 20 in-house trainings and 2 ‘kaizen’ events including motivational training have been initiated with 54 documents being revised and improved in order to contribute to more efficient processes.
Keywords: lean manufacturing, confectionery production, benefits, constraints
Published: 04.12.2017; Views: 593; Downloads: 97
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Experimental investigation of the quality and productivity of software factories based developmentAndrej Krajnc
, Marjan Heričko
, Črt Gerlec
, Uroš Goljat
, Gregor Polančič
, 2012, original scientific article
Abstract: Software organizations are always looking for approaches that help improve the quality and productivity of developed software products. Quality software is easy to maintain and reduces the cost of software development. The Software Factories (SF) approach is one of the approaches to provide such benefits. In this paper, the quality and productivity benefits of the SF approach were examined and evaluated with an experiment involving two treatments - the traditional and the SF approach. For the purposes of this experiment, the Goal – Question – Metric (GQM) approach was used. Participants were grouped into thirty two teams. There were sixteen projects available. The results were evaluated and presented through quality and productivity criteria, which were used for the experimental study. The results showed that the Software Factories approach was significantly better than the traditional approach.
Keywords: software factories approach, benefits, quality, productivity, experiment
Published: 06.07.2017; Views: 665; Downloads: 293
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Challenges and advantages of recycling wrought aluminium alloys from lower grades of metallurgically clean scrapVaružan Kevorkijan
, 2013, review article
Abstract: In the recycling of wrought aluminium alloys from lower grades of scrap (metallurgically clean but highly contaminated with non-metallic impurities) the following two tasks were identified as the most demanding: (i) achieving the required final chemical composition of an alloy with a minimal addition of primary aluminium and alloying elements; and (ii) keeping the level of impurities (inclusions, hydrogen, trace elements and alkali metals) in the molten metal below the critical level. Because of the lack of chemically based refining processes for reducing the concentration of alloying and trace elements in the molten aluminium, once the concentrations of these constituents in the melt exceed the corresponding concentration limits, the only practical solution for their reduction would be an appropriate dilution with primary metal. To avoid such a costly correction, carefully predicting and ensuring the chemical composition of the batch in the pre-melting stage of casting should be applied. Fortunately, some of the impurities, like hydrogen and alkali metals, as well as various (mostly exogeneous) inclusions, could be successfully reduced by employing existing refining procedures. In this work, (i) the state-of-the-art technologies, including some emerging technical topics such as the evolution of wrought alloys toward scrap-intensive compositions, monitoring of the content of organics in the incoming scrap and the quality of molten metal achieved by different smelting and refining technologies, and (ii) the relevant economic advantages of the recycling of wrought aluminium alloys from the lower grades of scrap are reported. By analyzing the market prices of various grades of scrap and the total cost of their recycling, the cost of aluminium ingots made from recycled aluminium was modelled as a function of aluminium and the alloying-element content in the incoming scrap. Furthermore, scrap mixtures for producing aluminium wrought alloys of standard quality from lower grades of scrap and with a significant new added value were illustrated.
Keywords: wrought aluminium alloys, recycling, low grades of aluminium scrap, quality of recycled metal, economic benefits
Published: 21.12.2015; Views: 1007; Downloads: 29
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COMPREHENSION OF HUMOR IN YOUNG LEARNERS OF ENGLISH IN SLOVENIAMateja Cartl
, 2014, master's thesis
Abstract: The master's thesis deals with the analysis of coursebooks for high school students, published by Oxford UP. Specifically we were interested in the amount of humor included, its types, its purpose and whether humor in coursebooks is culturally bound. The thesis also deals with the amount of humor understood by students. It examines the role of gender, class and school. The study involved 345 students from different grammar and vocational schools from the Education Institute in Maribor. The data for students were gained with the help of the questionnaire. The Coursebook analysis showed that there is not enough humor included in the coursebooks. Humor that is included, however, lacks type diversity. Further, the results from the analyzed student’s answers show that the students understand humor; however, most of the students (especially male students and students that go to vocational school) do not find the cartoons which contain general humor funny. The students preferred culturally bound humor.
Keywords: humor, benefits, disadvantages, coursebooks, comprehension.
Published: 28.07.2014; Views: 1164; Downloads: 136
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