Browsing by Author "Silva, F. J. G."
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- Analysis and improvement in the Electrical Discharge Machining process used on the manufacturing of moulds for plastics injection mouldingPublication . Costa, A; Pinto Ferreira, Luís; Silva, F. J. G.; Sá, José Carlos; Pereira, Teresa; Ávila, PauloDue to increasing competitiveness in the industry, companies will invariably adopt strategies to ensure that their employees continuously eliminate waste and create more value. This concept was applied at a company that designs, develops, and manufactures steel moulds for the injection of thermoplastics, with the purpose of implementing Lean thinking in the production sector, thus achieving the following objectives: organization of production; preparation of documents to support production, and standardization of graphite stock. Regarding the application of the 5S tool, an improvement in worker safety, and in cleaning was observed, which also led to a reduction in the time wasted when locating tools. Through the implementation of 5S auditing, enabling to verify an overall improvement, from a rating of 35% in the first audit to 85% in the subsequent audit. The tools implemented allowed for improvements in communication between sectors, leading to increased productivity and productive autonomy. Finally, graphite stock was standardized by means of Kanban.
- Comparative study of PVD and CVD cutting tools performance in milling of duplex stainless steelPublication . Martinho, R. P.; Silva, F. J. G.; Martins, C.; Lopes, H.The machining process evolution has been accompanied by the improvement of tool performance, being this mainly due to the development of thin coatings, mono and multi-layered, providing the most appropriate set of properties for each machining condition. On the other hand, duplex stainless steels have registered a strong increase in demand, which, in many cases, requires the use of machining processes in order to obtain the final shape accurately. Taking into account these two aspects, this paper aims essentially to evaluate the performance of two cutting inserts with PVD and CVD coatings, used in rough milling operations of duplex stainless steel. The cutting parameters and machining conditions were those recommended by the manufacturer and were kept unchanged in all performed tests. The behavior of the PVD- and CVD-coated cutting tools was assessed using three different facets: (a) surface roughness analysis, (b) tool wear evaluation, and (c) the monitoring of vibration levels produced during each test. CVD (TiN/TiCN/Al2O3)-coated inserts showed very good suitability to be used as tools for roughing milling operations when machining super duplex stainless steels.
- LEAN and ergonomics: how to increase the productivity improving the wellbeing of the workers – a case studyPublication . Santos, J.; Silva, F. J. G.; Pinto, Gustavo Filipe; Baptista, AndresaThe principles of Lean manufacturing, in addition to addressing the reduction of waste throughout manufacturing processes, are also highly concerned about the conditions that can favor the productivity of operators, which is achieved through their well-being while performing tasks. This work was elaborated with a view to the analysis of a production line capable of producing different electronic devices and which presented deficiencies in terms of operator ergonomics, demanding undesired and exhausting efforts, having as aim the elimination of such conditions. Thus, a detailed study of the movements carried out by the operators along the assembly line was elaborated, and possible solutions were considered to eliminate the situations that were perceived as more tiring and capable of generating health problems for the operators, when repeated several times. The study was successfully developed, and solutions were found that completely eliminated actions that required exaggerated efforts or unnecessary movements, clearly optimizing the assembly flow and the well-being of the operators in the line.
- Lean manufacturing applied to a complex electronic assembly linePublication . Silva, F. J. G.; Baptista, Andresa; Pinto, Gustavo Filipe; Correia, DamásioManual assembly lines are usually deeply studied before implementation. Nevertheless, several problems upsurge when the product needs to be slightly changed. This is very common in complex electric and electronic devices usually produced in small batches, where the customers are demanding more and more features and the product needs to be continuously updated. However, these updates sometimes create huge difficulties for the previously installed assembly line, generating as well, line unbalancing and wastes of time regarding the initial situation. In this chapter, a deep study of an adjusted assembly line of electronic devices was carried out using Value Stream Mapping (VSM) method to fully understand and document the different tasks and operations. The Lean Line Balancing (LLB) was also applied in order to reduce the line bottleneck by balancing the line, becoming the Cycle Time (CT) lower than Takt Time (TT) in each workstation and the workers are not overburdened with their task. Standardized processes and standardized work were also applied. During the line layout development stage, assembly fixtures, wastes reductions and visual management techniques were applied as well, different concepts were generated and proposed and, finally, the best solutions were selected. Throughout the study, many benefits for the studied manual assembly line were found, which can be considered as a strong motivation to apply Lean Manufacturing (LM) tools for better line efficiency and production rate. The implementation of Lean methodologies endorsed an increase in the productivity of approximately 10% maintaining the same workforce, only modifying workstations and work methodologies. This chapter describes the importance of Lean manufacturing concept in modern industries.
- Lean Safety - assessment of the impact of 5S and Visual Management on safetyPublication . Sá, José Carlos; Manuel, V; Silva, F. J. G.; Santos, G; Pinto Ferreira, Luís; Pereira, Teresa; Carvalho, MThis study was developed in a furniture company and aimed to implement some Lean tools, such as 5S and Visual Management to reduce waste, by improving the production process. To carry out this analysis an observation plan was used, having the Spaghetti diagram as a reference as well as the value-added analysis of the operations. The implementation of 5S's allowed the improvement of the visual management and the organization through a reorganization of the layout, as well as normalization of the production process. With this, a reduction of 40% was achieved in terms of waste related to activities that did not add value to the product, such as unnecessary movements, waiting times and even movement of materials, having achieved a level of productivity of 74% and 87% in the finishing and joinery sections, respectively. In addition to improvements in the production process, the impact of the measures at the safety level (lean safety) was assessed. For this purpose, a questionnaire was prepared to assess the opinion of the employees, in which 40% considered that the implementation of the tools provided a greater motivation to develop their work activities safely
- Machining Duplex Stainless Steel: Comparative Study Regarding End Mill Coated ToolsPublication . Gouveia, Ronny M.; Silva, F. J. G.; Reis, Pedro; Baptista, A. P. M.The difficulties in the machining of duplex stainless steel are well known. However, research on this matter is rather limited. Suppliers offer quite different cutting tools for the same raw material, with end mills of two, three or even four knives and a huge number of distinct coatings, some of them under commercial brands, making it difficult to assess the advantages they offer. Furthermore, there is a remarkable difference among the several types of duplex stainless steel available nowadays on the market. The present work intends to assess the machining performance of different tools, analyzing the behavior and wear mechanisms with two different cutting lengths, keeping constant the machining trajectory. Some other parameters were also kept constant, such as cutting speed, depth of cut and cutting width, as well as feed per tooth. The machining process was carried out under lubricated conditions, using an emulsion of 5% oil in water. Tools provided with a different number of teeth and surface coatings were tested, analyzing the wear behavior of each cutting length using scanning electron microscopy, trying to identify wear performance and how each coating contributes to increased tool life. The surfaces produced were also analyzed by means of profilometry measurements, correlating tool wear and part surface roughness. This comparative study allows determining the advantages of different tools relative to others, based on coatings and tool geometry.
- A novel concept of bent wires sorting operation between workstations in the production of automotive partsPublication . Magalhães, A. J. A.; Silva, F. J. G.; R.D.S.G., CampilhoThe most important goals pursued by the automotive industry for a long time are the quality and the delivery time. In order to ensure that such premises are fulfilled, it is necessary that these companies have machines with fast production cycles and versatile layouts, able to adapt to the production of a large number of different parts. At the same time, for some production lines to spend the shortest possible time, it is necessary that there are devices able to quickly perform the transposition from one stage of production to the next one, freeing operators to more attractive and personalized tasks. Thus, simultaneously it is possible to reach higher production cadences, with the corresponding financial gains, as well as an increase in workers motivation, which will be more productive. In this work, a novel concept of interconnection system between different manufacturing processes is presented in order to overcome the usual waste of time. Moreover, it is intended to show that, by replacing some robotized operation by cheaper automatic systems, it is possible to reduce the cycle time and improve the quality of the parts delivery from one operation to the next one. A case study is also presented corroborating this idea and showing how this principle can be applied in the field. The case study intends to show a novel device able to link the wire bending process and the further stage, the polymer over-injection process, in cushions and suspension mats for automotive seats.
- Open Innovation and Sustainable Development through Industry-Academia Collaboration: A Case Study of Automotive SectorPublication . Dieguez, Teresa; Pinto Ferreira, Luís; Silva, F. J. G.; Tjahjono, BennyThe purpose of this paper is to provide an insight on how companies based in Portugal and working for the automotive sector as spare-parts suppliers, uphold the notion of sustainable development and how they perceive the industry-academia collaboration as an adding value activity that improves productivity and efficiency. A qualitative study was conducted to collect empirical data by means of interviewing 29 representatives of the Portuguese automotive spare-parts manufacturers. It was found that, to a large extent, there is a significant gap between concerns, priorities and solutions amongst the respondents. The future will therefore depend on the way the stakeholders face problems, communicate and find forums for sharing ideas and build a well-developed world.
- Quality assessment in the manufacture of a pressure piping by weldingPublication . Pereira, A. B.; Cardoso, J. P.; Silva, F. J. G.This chapter presents the necessary requirements for the CE marking of a pressure piping assembled in welded construction. The Quality Management of a welded construction involves well-regulated procedures which, however, are so vast that they acquire great complexity. In fact, there are hundreds of rules to apply to each specific case. In the European Union, the CE marking shows the presumption that the products comply with all the provisions of the applicable directives. This marking is a way to improve the safety of consumers, as well as the guarantee of having a competitive and regulated market, therefore good for the economy itself. Pressure equipment is, as a rule, considered dangerous, and therefore subject to strict and careful regulation. The CE marking is not established as a technical barrier, which prevents countries from exporting their products to the European market. It is just one way of harmonizing and unifying procedures, standards and legislation that has the purpose of completing the European internal market. This paper presents an analysis of how to obtain CE marking of an execution and assembly of steel piping in a formaldehyde plant and which normative ramifications apply.
- Quality assurance of welded construction of industrial boilersPublication . Pereira, A. B.; Martinho, J. C. F.; Silva, F. J. G.Quality assurance is an essential and indispensable requirement in metalworking. The obligation of manufacturers to comply with this requirement depends on the framework and scope applicable to the product. Thus, the manufacturer must not only know and respect the current legislation and regulations, but also the extensive standardization applicable to the products. Specially, manufacturers whose product is based on welded construction and subject to CE marking, have the obligation to know and implement all the necessary provisions for the conformity of the product from its conception to the availability of the product on the market. In this case, the objective of this work is to describe, specify and solve the various steps that allow a manufacturer of steam boilers to guarantee the quality in the welded construction of their product, with all that this implies. Nowadays the manufacturer's problem is not the quantity and capacity of the physical resources of manufacture, but rather the mastery of the technique and actuality of specific knowledge required to ensure the product compliance. A methodology to approach construction is proposed, assuming the manufacturer role, from the framing of the product to inspection and final testing. It is intended to detail and technically fully document each step, in accordance with the legislation and building codes applicable to the boiler under study.