Formalization of requirements for assembly of high-precision units during process design of production of multi-product machining systems

This article considers the improvement of mathematical and methodological support of the implementation of an enlarged block of design procedures of the analysis of requirements of the assembly of high-precision products of the complex of design procedures of the system of accounting requirements for the assembly in the design of manufacturing methods of machining. The proposed modernization will allow to more efficiently perform of the design dimensional analysis of a high-precision assembly unit in an automated fashion and choose rational manufacturing methods of machining of parts in the system of automated sequencing of manufacturing methods during process design of the production of multi-nomenclature machining complexes. In addition, the proposed solutions allow for the expansion of digitalization of designing preproduction and process design and the transition to intelligent production systems. The problem posed in the presented study is relevant, since the proposed solutions allow for the expansion of digitalization of designing preproduction and process design and the transition to intelligent production systems in the future.

Experimental Studies of the Electrochemical Method of Water Purification in the Subarctic Territories

Outcomes of experimental, analytical, statistical research on aquatic mediums in various conditions of the Maata river’s diffuse sources, village Berdigestyakh (Yakutia), by using the electrochemical coagulation method, substantiation of optimal parametrization of water purification have been presented. The study’s results of using a non-routine electrochemical conditioning method to produce the high-quality drinking water without chemicals from the surface water of the river Maata to comply with the drinking water treatment requirements have been elaborated. The test approval of soluble electrodes has been carried out with the St3 steel to assess their efficiency while applying the electrochemical treatment of low-mineralized high and duckweed covered northern water systems. The modes for water electrochemical conditioning have been identified and substantiated, structural elements and parameters of the core assembly unit have been developed for implementing the electrocoagulation method under the village Berdigestyakh conditions, as well as schematic diagrams of their arrangement into separate modules of various capacities.

TECHNOLOGICAL SUPPORT OF CONTACT RIGIDITY OF MACHINE PARTS

Examples of solving problems according to the method described in the first part of this work in the processing of contacting surfaces by turning, milling and grinding, as well as the comparison of calculated and experimental values of the contact convergence of surfaces, and the algorithm for calculating the determination of machining modes in order to ensure a given contact stiffness are given. The article describes the practical application of the research results in relation to the assembly unit of an aircraft gas turbine engine.

By the problem of the possibility of technological movement of large assembly units along ice transportation routes

В настоящей работе авторами приводится теоретический анализ практической возможности транспортирования тяжеловесного судового оборудования или сборочно-монтажных единиц (СМЕ) судового оборудования по специально созданным технологическим ледяным путям. Для обоснования выбранной темы научного исследования авторы ссылаются на ряд литературных источников, посвященных вопросам практического использования льда в качестве материала для транспортирования различных грузов. Приводятся примеры использования льда для создания: взлетно-посадочных полос аэродромов; переправ через водные преграды; зимних трасс в северных широтах в Росси и ряде других стран для транспортирования тяжеловесных сооружений и т.п. Авторами рассматриваются физико-механические свойства пресноводного льда с целью определения параметров транспортировочных балок, включающих в свой состав опорный ледяной массив. В статье приведена схема расположения и назначение элементов транспортировочной оснастки, расположенной под полкой агрегата СМЕ. Выполненное теоретическое исследование совместной работы транспортировочной балки с ледяным массивом, упругой компенсирующей прокладкой и жесткой полкой СМЕ позволило установить взаимосвязь толщины ледового бруса и толщины прокладки с упругой деформацией транспортировочного пути и его жесткостью, используя которую можно обоснованно назначать: - толщину сечения ледового бруса и грузонесущей балки; - параметры сечения и материал компенсирующей прокладки; - размеры транспортировочной балки и в целом конструкцию транспортировочных путей. In this article, the authors investigate the theoretical analysis of the practical possibilities of transporting heavyweight ship equipment or assembly units of ship equipment on the specially created technological ice paths. For substantiate the chosen theme of scientific research, the authors refer to a number of scientific sources devoted to the practical use of ice as a material for the transportation of various cargoes. Examples of using ice to create: airfield runways; crossings over water obstacles; winter routes in the northern territories of Russia and other countries for the transportation of heavy constructions, etc. The authors investigate the physical and mechanical properties of freshwater ice in order to determine the parameters of the transport beams, which include the supporting ice block. The article shows the layout and purpose of the elements of the transportation equipment located under the shelf of the assembly unit. The results theoretical research of the operation of a transport beam with the ice block, the elastic compensating gasket and the bearing construction assembly unit made possible to determine the correlation between the thickness of the ice block and the thickness of the gasket with the elastic deformation of the transportation path and its rigidity, using which one we can reasonably assign: - the thickness of the section of the ice block and the load-carrying beam; - section parameters and material of the compensating gasket; - the parameters of the transport beam and the construction of the transport routes in general.

Digital plant: methods of discrete-event modeling and optimization of production characteristics

This article presents a new approach to the development of a ‘digital twin’ of a manufacturing enterprise, using a television manufacturing plant as the case study. The feature of the proposed approach is the use of hybrid methods of agent-based modeling and discrete-event simulation in order to implement a simulation model of a complex production process for assembling final products from supplied components. The most important requirement for such a system is the integration of all key chains of a digital plant: conveyor lines, warehouses with components and final products (TVs), sorting and conveyor system, assembly unit, technical control department, packing unit, etc. The proposed simulation model is implemented in the AnyLogic system, which supports the possibility of using agent-based and discrete-event modeling methods within one model. The system also supports using the built-in genetic algorithm to optimize the main parameters of the model: the most important production characteristics (for example, assembly time of a product, the number of employees involved in assembly, quality control and packaging processes). Optimization experiments were completed with the help of the developed model at various intensities of loading conveyor lines with components, various restrictions on labor resources, etc. Three scenarios of the production system behavior are investigated: the absence of the components deficit with the possibility of significantly increasing the labor resource involved, a components deficit while demand for final products is maintained, and the presence of hard restrictions on the number of employees who can be involved in the processes under conditions of components deficit.

Screening of Work-Related Musculoskeletal Upper Limb Disorders Using the SALTSA Protocol: A Work-Site Study in Belgium

Background: Long-term absenteeism continues to rise in Belgium and musculoskeletal disorders (MSDs) have been considered a primary cause. However, there is still uncertainty about the prevalence of MSDs, and about the contribution of work-related factors in the etiology of MSDs. SALTSA, which was developed in 2001, is a European diagnostic criterion document that aims to standardize the reporting of work-related upper limb MSDs (ULMSDs). The purpose of this work-site study was to implement SALTSA in daily occupational health practice and to determine the prevalence of ULMSDs in a Belgian company. Methods: During health examinations, occupational health nurses and an occupational health physician screened employees in a company with ergonomically high-risk activities for the occurrence of ULMSDs using the SALTSA protocol. In order to explore associations between ULMSDs and lifestyle and work-related factors, bivariate and logistic regression analyses were performed. Findings: Three hundred and eight (94.0%, 308/328) employees were screened resulting in an ULMSD prevalence of 20.5% (95% CI = [16.0–25.3]). Rotator cuff syndrome was the most common condition. Prevalence varied significantly between men (9.6%, 95% CI = [5.6–14.9]) and women (35.0%, 95% CI = [26.9–43.9]). Being female ( p < .001) and working in the cabling assembly unit ( p = .002) were found to be significant predictors of ULMSDs. Conclusion/Application to Practice: By using the SALTSA protocol in occupational health practices, ULMSDs can be screened unequivocally, enabling comparisons between different occupational sectors and countries. Occupational health nurses can play an important role in detecting and screening MSDs among workers.

Effect of Assembly Unit of Expansive Agents on the Mechanical Performance and Durability of Cement-Based Materials

This paper studies the influence of assembly unit of expansive agents (CaO and calcium sulphoaluminate) on the limited and free compressive strengths, the limited expansion rate, carbonation resistance, chloride ion penetration resistance and corrosion resistance of reinforcement concrete. The dosages of expansive agent were 0%, 3%, 6%, 9%, and 12% by the total amount of cementitious materials. Two kinds of mineral admixture (blast furnace slag and fly ash) were applied in this study. Results show that suitable dosage (lower than or equal to 9%) of double expansion agent with a large amount of mineral admixtures can improve the limited and free compressive strengths. However, when the dosage of the double expansion agent is higher than 9%, the addition of the double expansion agent leads to the reduction of limited and free compressive strengths. The variation of the limit expansion rate reaches the maximum value when the curing age is 14 days. The increasing addition of expansive agents and lower water-binder ratio demonstrate positive effect on the limited expansion rate. Concrete with 60% mineral admixtures (fly ash and ground granulated blast furnace slag) shows lower limited expansion rate and higher compressive strength than the concrete with 50% mineral admixtures. Finally, the incorporation of double expansion agent can improve the resistance to carbonation, chloride ion penetration resistance, anti-corrosion of steel bars and mechanical strengths (the limited and free compressive strengths).

Influence of Rust Inhibitor on the Corrosion Resistance of Reinforcement in Cement Paste with Chloride

The electrical resistance and polarization effect of cement paste containing reinforcement were tested to research the anti-corrosion properties of steel bars in cement paste. Moreover, the microstructure and composition of passivation film and rust on the steel bars were studied. The water–cement ratio of the cement paste in this study was 0.3, with 0.5% NaCl, 1% NaNO2, and 1% Benzotriazole, and an assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole by mass of cement was added to the cement to provide a chloride environment. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were applied to research the composition of the passivation film and the microstructure of the cement paste, respectively. The results indicated that the samples with the assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole showed the highest electrical resistance and polarization electrical resistance, while the specimens with 1.0% Benzotriazole showed the lowest electrical resistance and polarization electrical resistance. Moreover, the passivation film of steel bars weakened with increasing distance from the surface of the steel bars. Therefore, the corrosion of steel bars becomes more serious with increasing distance. Finally, the influence of the rust inhibitor on the corrosion resistance of steel bars in the specimens decreased in the following order: 0.5% NaNO2 + 0.5% Benzotriazole >1.0% NaNO2>1.0% Benzotriazole.

Strategi Mitigasi Risiko Produktivitas Pada Proses Assembly Hospital Equipment

The rapid development of technology and industrialization demands an increasing need for strategic planning. One of the strategies needed for a company to remain competitive in the industrialized world is to increase productivity. However, practically several companies still experience difficulties in making efforts to increase productivity so that the productivity achieved is not optimal. The same thing happened at PT. Mega Andalan Kalasan, especially on the Assembly Unit of the Hospital Equipment. Where the productivity achieved cannot be categorized as optimal because it can be seen from the number of non-value added activities that occur in assembly process. Among the products produced, it is known that the Operating Table Manual product has the highest percentage of non-value added activity, which is 30% of the total cycle time. This study aims to identify risks using the Failure Mode and Effect Analysis (FMEA) method and design a mitigation strategy as an initial effort to improve productivity by minimizing non-value added activities. The identification results show that there are 22 risks with moderate severity but high occurrence. Recommendations in the form of implementing better quality control on incoming materials are one of the strategies which capable of mitigating 40% of the risk of existing non value added activities. Adanya perkembangan teknologi dan industrialisasi yang semakin pesat menuntut kebutuhan akan perencanaan strategi semakin meningkat. Salah satu strategi yang dibutuhkan agar sebuah perusahaan dapat tetap bersaing di dunia perindustrian adalah dengan meningkatkan produktivitas. Namun pada penerapannya, beberapa perusahaan masih mengalami kesulitan dalam melakukan upaya peningkatan produktivitas sehingga produktivitas yang dicapai belum optimal. Hal yang serupa terjadi di PT. Mega Andalan Kalasan, khususnya pada lantai kerja Assembly unit Hospital Equipment. Dimana produktivitas yang dicapai belum bisa dikatakan optimal karena terlihat dari banyaknya non value added activity yang terjadi pada proses assembly. Diantara sejumlah produk yang dihasilkan, diketahui bahwa pengerjaan produk Operating Table Manual memiliki persentase non value added activity yang tertinggi yaitu sebanyak 30% dari total waktu siklusnya. Penelitian ini bertujuan untuk mengidentifikasi risiko dengan menggunakan metode Failure Mode and Effect Analysis (FMEA) dan merancang strategi mitigasi sebagai upaya awal untuk memperbaiki produktivitas dengan meminimalisir aktivitas non value added. Hasil identifikasi menunjukkan terdapat 22 risiko dengan tingkat severity sedang namun memiliki occurence yang tinggi. Rekomendasi berupa penerapan quality control yang lebih baik terhadap incoming material menjadi salah satu strategi yang mampu memitigasi 40% risiko aktivitas non value added yang ada.