DESIGN AND CALIBRATION OF THE SYSTEM SUPERVISING BELT TENSION AND WEAR IN AN INDUSTRIAL FEEDER

In the paper, the issue of the supervision of belt tension and wear in industrial feeder is addressed. The designed system is based on strain gauges that are built into the roller and are subject to the belt pressure at each revolution. In order to assess the effectiveness of this system, calibration and uncertainty analysis was performed. As a result, it was demonstrated that the main source of uncertainty was the function of approximation, while the others were orders of magnitude smaller. The final function provided results with accuracy of ca. 10% of actually measured value, which was assumed to be a good result for this particular industrial application

The assessment of the local security policy efficiency

Purpose: The purpose of this article is to assess the local security efficiency across the districts of the Kuyavian-Pomeranian province in northern Poland. The authors are looking for an answer to the following questions: does the local security policy live up to its expectations, i.e., do citizens feel safe at their place of their residence, and how do they assess the individual components of the local security system? How do residents perceive local security depending on their place of residence across the Kuyavian-Pomeranian province? Design/Methodology/Approach: In order to achieve the goal of the research, the authors conducted a survey employing a sample of 4500 residents of the Kuyavian-Pomeranian province. Based on the survey findings and using linear ordering methods, a ranking of districts of the Kuyavian-Pomeranian province was compiled. Findings: There are significant discrepancies between the subjective assessment of local security efficiency by the residents and its objective evaluation conducted with indicators. Generally, the residents of the districts of the Kuyavian-Pomeranian province are much more content with the local security system than implied by traditional indicators. Practical Implications: The findings of the research are of great significance to local authorities as they allow them to design the systems of local development management more effectively by taking account of the residents’ opinions on the individual components of the security system. Originality/Value: The research was conducted on a relatively extensive group of respondents. The presented findings proved the usefulness of the multidimensional analysis and linear ordering methods in the assessment of local security policy efficiency.peer-reviewe

Process layout planning and optimised product range selection in manufacture of wooden construction sets

This paper introduces a systematic deterministic framework for planning and the analysis of facility layouts aimed at manufacturing a variety of parts, being components of specific end products. The essence of the proposed approach lies in the decomposition of a traditional job-shop into layout modules of generic material flow patterns, that inherently yields improved efficiency of the entire system. It entails the use of a relevant reasoning scheme based on production flow analysis and the method of hierarchical clustering of specified process routings for parts. The approach has been studied in the aspect of its application in an actual woodworking facility, dealing with fabrication of wooden toy sets. The respective workflows were subjected to the analysis in order to identify production bottlenecks using data derived from the real case study. As a result, the designated process layout alternatives have been evaluated in terms of assumed measures of the operational performance. An inseparable part of the research was exploring the capability for the optimum selection of a multi-part product mix , to be fabricated in defined time frames. In this regard, the usability as well as the computational efficacy of the integer linear programming modelling have been fully confirmed. The results gained show in particular that the suggested methodical scheme could be a useful tool in planning optimised manufacture of customised wood products of modular construction

A dynamic programming model for designing a quality control plan in a manufacturing process

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Process quality planning should establish the quality control plan to achieve the desired quality level with the minimum quality cost (appraisal and failure costs) for the final product. This plan sets out the critical quality variables, the control stations in the process, and the control method at each control station. The quality costs associated with quality control and defective products can be greater than or less than ideal regarding the required quality level. The purpose of this paper is to provide a stochastic dynamic programming model for designing the quality control plan in a manufacturing process, which allows obtaining the desired level of control with the lowest cost. Inputs to the model are, in particular, control stations in the process, levels of quality, control methodologies (no control, statistical process control, 100% inspection), probabilities of changing the quality level and quality costs. The output of this model is the quality control plan that satisfies the desired level of quality at the lowest cost. This plan establishes the control stations, the methodology used in each control station, the desired quality level for the final product, and the estimated quality costs. Finally, an illustrative example based on a manufacturing process demonstrates the applicability of this approach and several considerations are reported about future research directions.FCT - Fundação para a Ciência e a Tecnologia(UID/CEC/00319/2019

Monitoring of the grinding system of forged crankshafts for marine engines

Monitoring of the grinding system of forged crankshafts for marine engines = Моніторинг системи шліфування кованих колінчастих валів для суднових двигунів / З. Сементковскій, М. Руцький, Д. Морозов, Р. Мартиновський, О. Шелковий, Ю. Гуцаленко // Зб. наук. пр. НУК. – Миколаїв : НУК, 2019. – № 1 (475). – С. 43–50.У статті розглядаються проблеми управління процесом шліфування, що виникають під час виробництва кованого колінчастого вала суднового дизеля. Представлений комплекс моніторингових заходів для оцінки можливості продовження ефективної експлуатації верстата в системі шліфування складного за формою і точністю, унікального за матеріаломісткістю і трудомісткістю виробу. Колінчасті вали великого розміру мають довжину до 12 м і важать до 25 тонн, але допуск на остаточне шліфування для діаметра становить 0,3–0,4 мм. Для цього необхідна дуже висока точність механічних деталей шліфувального верстата. Дослідження було зосереджено на вимірі таких параметрів, як площинність, лінійність, паралельність, биття і співвісність відповідальних за вихідну точність механічних частин шліфувального верстата. Робота виконана зі шліфувальним верстатом типу DB12500, оснащеним системою управління Sinumerik 840D, а також системами вимірювання та ексцентричної обробки. На підставі отриманих результатів були зроблені деякі рекомендації з процедури перевірки з метою забезпечення стабільної якості випуску колінчастих валів. Шліфувальним інструментом був шліфувальний круг дискового типу Molemab B126-100639 S.630090. Вибір хімічно інертного до оброблюваного матеріалу з вмістом вуглецю і водночас особливо твердого абразивного інструментального матеріалу (c-BN), а також значна протяжність робочої частини шліфувального круга по периферії (понад 6 м), є важливою передумовою забезпечення стійкості інструменту в циклі продуктивної і якісної зовнішньої обробки заданих функціональних поверхонь розглянутих великогабаритних колінчастих валів. Припуски на обробку розподілялися між попереднім і чистовим переходами шліфування з деяким збільшенням (резервуванням забезпечення точності) для шатунних шийок, обробка яких велася другим планом. Мікрогеометричну якість поверхні контролювали за допомогою портативного вимірювача шорсткості поверхні Surftest SJ-201P, що дозволило уникнути очевидних проблем вимірювання профілю в задачах контролю великогабаритних деталей складної ступінчастої форми, якими є суднові колінчаті вали. Отримані параметри шорсткості після шліфування (Ra ≤ 0,4 мкм) були визнані вагомою мірою задовільними, що дозволило після цього ефективно полірувати до необхідного за основними функціональними поверхнями рівня Ra 0,3 мкм. Виконана робота може розглядатися як методичний прообраз моніторингів в дорожніх картах експертизи стану параметрів точності шліфувальних верстатів і рівня мікрогеометричної якості обробки колінчастих валів.The article discusses the problems of controlling the grinding process that arise in the production of forged crankshaft of marine diesel. A set of monitoring measures is presented to assess the possibility of continuing the effec- tive operation of the machine in a grinding system of the product of complex shape and accuracy, unique in terms of material consumption and labor intensity. In the paper, grinding process control problems that occur during the marine diesel engine crankshaft production are addressed. The large size crankshafts have a length of up to 12 m and weigh up to 25 tons, but the final grinding allowance for the diameter is ca. 0.3–0.4 mm. To achieve this, very high accuracy of the mechanical parts of the grinding machine is necessary. The study focused on the measurement of parameters such as level, linearity, parallelism, runout and coaxiality of the respective mechanical parts of the grinding machine. The work was performed with grinding machine type DB12500, equipped with Sinumerik 840D control system, as well as measuring and eccentric processing systems. Based on the results, some recommendations were made on the inspec- tion procedure in order to ensure a consisted quality of the produced crankshafts. The grinding tool was a Molemab B126-100639 S.630090 disc type grinding wheel. The choice of chemically inert to the carbon-containing material to be processed and especially hard abrasive tool material (c-BN), as well as a considerable length of the working part of the grinding wheel around the periphery (over 6 m), are an important prerequisite for ensuring tool durability in the cycle of productive and high-quality external processing of specified functional surfaces of considered large crank- shafts. Processing allowances were distributed between the preliminary and final grinding transitions with a slight in- crease (redundancy to ensure accuracy) for crank-pins, which were processed by the second plan. The microgeometric surface quality was controlled using a Surftest SJ-201P portable surface roughness meter, which avoided the obvious problems of stationary profilometry in the control of large-sized multiple-profile parts, such as shipboard crankshafts. The obtained roughness parameters after grinding (Ra ≤ 0.4 μm) were found highly satisfactory, allowing effective polishing afterwards up to the level of Ra 0.3 μm necessary for the main functional surfaces. The work performed can be considered as a methodological prototype of monitoring in roadmaps for examining the state of the accuracy param- eters of grinding machines and the level of microgeometric quality of processing crankshafts

Process layout planning and optimised product range selection in manufacture of wooden construction sets

This paper introduces a systematic deterministic framework for planning and the analysis of facility layouts aimed at manufacturing a variety of parts, being components of specific end products. The essence of the proposed approach lies in the decomposition of a traditional job-shop into layout modules of generic material flow patterns, that inherently yields improved efficiency of the entire system. It entails the use of a relevant reasoning scheme based on production flow analysis and the method of hierarchical clustering of specified process routings for parts. The approach has been studied in the aspect of its application in an actual woodworking facility, dealing with fabrication of wooden toy sets. The respective workflows were subjected to the analysis in order to identify production bottlenecks using data derived from the real case study. As a result, the designated process layout alternatives have been evaluated in terms of assumed measures of the operational performance. An inseparable part of the research was exploring the capability for the optimum selection of a multi-part product mix , to be fabricated in defined time frames. In this regard, the usability as well as the computational efficacy of the integer linear programming modelling have been fully confirmed. The results gained show in particular that the suggested methodical scheme could be a useful tool in planning optimised manufacture of customised wood products of modular construction