Papers by Keyword: Manufacturing

Abstract: Nowadays the flexibility and specific cost of manufacturing have a relevant role in the competitiveness of the companies. In our opinion the most important objective of Industry 4.0 is the realization of intermittent manufacturing at mass production’s productivity and specific cost. This aim can be only reached by creating more complex manufacturing systems. The increase in manufacturing complexity results in new challenges in the quality assurance of manufacturing processes. We can collect new types of data that enable the improvement of product and process service quality. This paper introduces the essence of Industry 4.0, as well as the new challenges for the quality assurance of manufacturing processes. Possible research directions for overcoming challenges are also presented.

Abstract: Logistic process is a basic factor in the success of manufacturing plants’ operation and has a direct impact on its efficiency, flexibility and reliability. Today’s successful operation of manufacturing processes views logistics as a high priority to ensure maximum utilization of resources. The material supply of manufacturing processes in the automotive industry is usually based on supermarkets and milk runs. This paper proposes an integrated supply model of manufacturing processes, which includes facility location and assignment. After a careful literature review, this paper introduces a mathematical model to formulate the problem of supermarkets and milk run based supply of machines. The model seeks the optimal location of buffers as well as the optimal assignment of buffers and machines so as to minimize the material handling costs while taking into account order limits of machines and capacities of resources. Next, we demonstrate an enhanced black hole algorithm dealing with multi-objective supply chain model to find the optimal structure of the system. Numerical results demonstrate how the proposed model supports the efficiency, flexibility and reliability of the manufacturing process.

Abstract: This paper presents different examples of automatic generation of queries to be implemented in a b-learning platform. Queries can be used as complementary contents and self-assessment by students in Manufacturing Processes subjects. They are useful when the available time for classroom teaching is reduced and also in blended applications, allowing students the consolidation of in-person received knowledge. Firstly, some considerations about the teaching of Manufacturing Processes subjects and about the types of queries to be generated automatically are explored. Secondly, a list of potential manufacturing topics for which this methodology is suitable is proposed, selecting three of them. Finally, and by means of non-specialized computer tools, an example of application is developed and the obtained results are presented in each topic.

Abstract: Fibre Bragg Grating (FBG) sensors are frequently being used for Structural Health Monitoring (SHM) of aerospace structures. One of the most important advantages of using FBG sensors is that it is possible to embed them into composites. In this paper, manufacturing methods of composite specimens with embedded FBG sensors are given. To avoid stress concentrations at ingress/egress regions of fibre optic wires, PTFE (Teflon) tubes were used during manufacturing. Moreover, FBG connectors melt at high curing temperatures. Therefore, those connectors were cut and after manufacturing, these connectors were spliced back to the FBG sensors. Embedded FBG’s were then checked and the correct wavelength data were taken. All the sensors were observed as intact and ready for bending tests. Procedure for bending tests is also explained including applied loads, boundary conditions, test setup and the peripheral equipment. Results of bending tests show that the system is an appropriate one for SHM purposes.

Abstract: Growing mechanical, economic and environmental specification lead to multi-material designs. Based on an extensive basic research, more achievements and experiences regarding the manufacturing technologies and mechanical properties of hybrid laminates were achieved in the Institute of Lightweight Structures and Polymer Technology. The present study shows the development, characterization and forming of novel hybrid laminates, made of steel sheets (HC220Y+ZE, t = 0.25 mm) and carbon fiber reinforced polymers (Polyamide 6). The interface-optimization of the hybrid laminates was carried out with two different bonding agents. The results of a three point bending test underline the potential of the innovative material. A hybrid roof crossmember was formed on a hydraulic Tryout-Press successfully.

Abstract: Synthesis of poly (1, 4-phenylene sulfide) (PPS) through oxidative polymerization seems promising to us. Comparing with current commercial method to poly (1, 4-phenylene sulfide) from 1, 4-phenylene sulfide and sodium sulfide (Phillips’ Method), there are many advantages of the oxidative polymerization method. For example, it can synthesize PPS at normal temperature and pressure; the yield of reaction is very high; it provides pure PPS without salt contamination. However, several years have passed away; synthesis of poly (1, 4-phenylene sulfide) through oxidative polymerization has not so far been adopted as the industrial process. Many of us are puzzled, why Through studying all kinds of reported preparation route to poly (1, 4-phenylene sulfide) through oxidative polymerization compared to Phillips’ Method, a generic polymerization mechanism is achieved for most of them excepting two with obvious shortcomings. We suddenly realize that synthesis of poly (1, 4-phenylene sulfide) through oxidative polymerization seems unsuitable to be used in industrial production recently because of its own limits.

Abstract: Fatigue failures occur due to the application of fluctuating stresses that are much lower than the stress required to cause failure during a single application of stress. The process is dangerous because a single application of the load would not produce any ill effects, and a conventional stress analysis might lead to assumption of safety that does not exist. The fatigue process is thought to begin at an internal or surface flaw here the stresses are concentrated, and consists initially of shear flow along slip planes. The mechanisms of fatigue-crack propagation are examined with particular emphasis on the similarities and differences between cyclic crack growth in ductile materials, such as metals, and corresponding behavior in brittle materials, such as intermetallic and ceramics. Fatigue, as understood by materials technologists, is a process in which damage accumulates due to the repetitive application of leads that may be well below the yield point.

Abstract: In recent times, lean manufacturing applications have become essential for manufacturers all over the globe. The manufacturers have gradually shifted from mass production to flexible manufacturing and customers are looking for customized and unique products. Productivity becomes a very important element with multiple product need. Passenger vehicle seat manufacturing industry is found to be poorly affected by manufacturing problems due to more cycle time, unbalanced workload and improper layout. The main aim of this paper is to study the existing system of a seat manufacturing industry and to improve productivity using lean methodology without much affecting current working systems. The critical non value added activities are identified and chances required for improvement has been recognized. The total lead time was reduced from 2.55 days to 2.438 days after implementation of applications of VSM. Using spaghetti diagram the current layout was optimized and the total cycle time was reduced by about 26.28% after implementing the proposed layout to meet the customer demand.

Abstract: Upon the attainment of independence many African countries emerged with a new spirit of entrepreneurial governance and domestic industrialization. However with time, most of the state owned enterprises (SOEs) set up have been privatized largely because of mismanagement, huge deficits and operational inefficiencies created by many factors. In all material moments, the objective of divesture of SOEs was to stimulate efficiency, productivity and relieve the state of the huge financial burden they bring. Our study examines the methods of privatization of healthcare technology and equipment SOEs in Africa and their impact on post-divestiture productivity based on cases from Ghana, Nigeria, Tanzania and Kenya.We simultaneously collect and model privatization data from International Monetary Fund (IMF) and the World Bank relating to Ghana, Nigeria, Tanzania and Kenya. These were data submitted to the IMF and World Bank as part of the measures to implement the different forms of economic recovery and structural adjustment programs in the respective countries. Our empirical strategy follows the broader literature in estimating reduced form equations for firm performance as a function of ownership, while trying to account for potential problems of heterogeneity (observed and unobserved) and simultaneity bias. We note the insider/employee shareholding accounted for only 23.6 percent of privatization of healthcare equipments and technology manufacturing enterprises on average while mass privatization program accounts for 18.2 percent of the privatization mode. We note that each of these methods yield positive post divestiture labour productivity. However privatization of healthcare equipment and technology manufacturing enterprises by block sale to outside investors generated the highest form of labour productivity.

Abstract: Until recently a lack of knowledge and understanding of the structural advantages of aluminium has limited the use of the material in building and construction. Today, advances in engineering and standardization have improved our knowledge of this versatile material and it is becoming more widely accepted in many industries.This paper contains examples of structural applications where aluminum has been selected for bridge construction in Europe: The first project was launched and supported by the E.U. and forms part of the European Cycle Route Network development. The second bridge structure is part of the tourist development program launched by the city of Vitre in France