Browsing by Author "Gouveia, R.M."
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- Improving manual assembly lines devoted to complex electronic devices by applying Lean toolsPublication . Correia, Damásio; Silva, F.J.G.; Gouveia, R.M.; Pereira, Maria Teresa; Ferreira, Luís PintoManual 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 paper, 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 Task Time (TT) of each workstation so that there are no delays, and nobody is overburden 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, 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.
- Improving the Cut Surface Quality by Optimizing Parameters in the Fibre Laser Cutting ProcessPublication . Amaral, I.; Silva, F.J.G.; Pinto, Gustavo Filipe; Campilho, R.D.S.G.; Gouveia, R.M.One of the main problems with laser cutting equipment is related to the wrong setting of cutting parameters. The mismatching of these parameters leads to a loss of cut surface quality, which is hardly re-established. This loss of quality is usually related to a burr problem. Thus, this study is aimed to improve and optimize this process using a fibre laser equipment. Three important laser cutting parameters were studied in order to investigate their importance in the cut surface quality: radiation power, cutting speed and gas pressure. The different values were performed cutting a stainless steel AISI 316L and a cold rolled steel St12. Metallographic and cut surface analysis, burr and roughness measurements were carried out, supported by a Scanning Electron Microscopy and profilometry. Through the Taguchi statistical analysis model, it is possible to indicate the best set of laser cutting parameters. It was verified that the values recommended by the equipment manufacturer can be optimized, being possible to use less radiation power in the laser beam with greater speed of cut, providing a better cut surface quality, improving and optimizing the entire process.
- A Novel Approach to Optimize the Design of Parts for Additive ManufacturingPublication . Silva, F.J.G.; Campilho, R.D.S.G.; Gouveia, R.M.; Pinto, Gustavo Filipe; Baptista, AndresaAdditive Manufacturing (AM) is a term used to group the different manufacturing processes that use various techniques, each of which is capable of producing parts made from a wide variety of materials, such as polymers, ceramics, metals, wood, among others. All these technologies allow parts manufacturing by adding successive layers of material which can be liquid, powder or wire. In order to take advantages of the geometric freedom offered by AM, Topological Optimization (TO) is usually used. TO provides the optimal distribution of material for a given request. The main objective is weight reduction, without compromising the original resistance of an existing part produced by traditional processes. Taking advantage of the freedom allowed by the AM process and conciliating it with the CAE features, which allow to simulate the parts behavior when subjected to the expected loads, a new approach methodology was drawn in order to shorten the time needed to optimize parts design for AM. A case study was developed in order to validate the methodology established. The combination of AM and TO revealed promising results, attending to the component efficiency achieved.
- The Improvement of an APEX Machine involved in the Tire Manufacturing ProcessPublication . Santos, R.F.L.; Silva, F.J.G.; Gouveia, R.M.; R.D.S.G., Campilho; Pereira, Maria Teresa; Ferreira, Luís PintoOver the years, there has been a huge expansion in the automotive component industry and its consequent innovation, which has evolved along with automation and robotics. Therefore, in order to ensure component quality, as well as the quality of the entire production process, it is crucial to enhance competitiveness in the sector. Since quality is a key feature in this industry, all manufacturers and suppliers are scrutinized by systematic audits to ensure constant improvements. This work was developed at a multinational industry and focuses on tire production for the automotive sector. Tires present a complex production process, which covers a wide range of activities from mixing, preparation, construction and vulcanization to the inspection departments, all of which are greatly predisposed to process improvement. In one of these departments (Preparation - APEX machines, responsible for the tire bead production), one of the main problems detected was directly related to a large number of failures in the pneumatic systems. These were found to be difficult to control, both in terms of speed and positioning. Some of the failures in automation were generating delays in certain processes, leading to lengthy setup times and culminating in higher production costs. In order to achieve greater quality, reliability and accuracy, a higher level of automation was applied to these kinds of machines by resorting to 5S methodology. A safety upgrade of the equipment was also undertaken, which will allow for the improvement of workplace safety.The performance improvement of the APEX machines was reached by implementing the following strategies: the automation of conveyor and tray movements between the cutting and application subprocesses; the implementation of 5S methodology; the automation of the cutting process; the updating of safety devices; and the automated control of the separation subprocess. A strong decrease in the breakdown time was recorded (-62%) resulting of the project implementation. The APEXmachine performance was also improved in 9%.