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- A codification system roadmap: case study in a metalworking companyPublication . Lemos, Carlos; Pereira, Maria Teresa; Ferreira, Luís Pinto; Silva, F.J.G.Decision-making and control of operational areas in industrial companies are key issues in their sustainability and resilience in markets that are more and more challenging and competitive. In this way, production management and information management software are becoming mandatory. The codification of information, namely products codification, is a subject, without being the main purpose in everyday companies’ work, must be a subject that enables a proper functioning of everyday companies’ activity. This project proposes a roadmap for internal product codification in a company working in the metalworking industry. This guide shows good practices that highlight formal basic rules whose could add value to internal processes of the organization and so to provide a solid system where the company can rely on providing more time to its workers to spend in other tasks. At last it is provided a generic conceptual model to serve as an approach to develop a codification system in any given organization.
- Implementation of Lean Methodologies in the Management of Consumable Materials in the Maintenance Workshops of an Industrial CompanyPublication . Pombal, Tomé; Ferreira, Luís Pinto; Sá, José Carlos; Pereira, Maria Teresa; Silva, F.J.G.During the course of the 21st century, companies have constantly had to adapt to change. The solution resides in increasing operational efficiency, quality and productivity, while simultaneously reducing costs and establishing the waste-free organization. The objective of this work lies in the implementation of lean methodologies in the management of consumable materials in the maintenance workshops of an industrial company by adjusting/reducing the volume of materials and reorganizing their placement. It further explores the potential to eliminate waste and create value-added tasks in the maintenance activities involved. The development of this work allowed for an improvement in the organization of the consumable material cabinet through the implementation of 5S methodology, as well as a reduction in the time required to locate the consumable material by using visual management (in the order of 70%). Improved control of stock was also achieved through the reformulation of kanban (approximately 30%); a reduction in the time required to replenish material in the consumables cabinet was ensured by means of the mizusumashi (with an expected improvement of 50%).
- 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%.
- GFRP waste reinforced polymer mortars: a new waste management solution for GFRP scrap materialPublication . Ribeiro, M. C. S.; Meira Castro, Ana C.; Fiúza, António; Dinis, M. L.; Silva, Francisco J. G.; Meixedo, João PauloTo date, glass fibre reinforced polymer (GFRP) waste recycling is very limited and restricted by thermoset nature of binder matrix and lack of economically viable enduse applications for the recyclates. In this study, efforts were made in order to recycle grinded GFRP waste proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, a mix of powdered and fibrous materials, were incorporated into polyester based mortars as fine aggregate and filler replacements, at different load contents (between 4% up to 12% of total mass) and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Test results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of GFRP waste reuse in concrete-polymer composites.
- Effect of material hybridization on the strength of scarf adhesive jointsPublication . Alves, D.L.; Campilho, R.D.S.G.; Moreira, R.D.F.; Silva, F.J.G.; Cardoso, M.G.Adhesively-bonded joints have become more efficient due to the improvement of adhesives’ characteristics. On the other hand, with the use of composites in structures it is possible to reduce weight. Due to this, new techniques are being explored, including adhesively-bonding different materials. Nowadays, in many high performance structures, it is necessary to combine composite materials with other light-weighted metals such as aluminium or titanium. This work reports on an experimental and numerical study for hybrid scarf joints between composite and aluminium adherends, and considering different values of the scarf angle (α). The numerical analysis by Finite Elements (FE), using the software Abaqus®, enabled the obtainment of peel (σy) and shear stresses (τxy), which are then used to discuss the strength between different joint configurations. Cohesive zone modelling (CZM) was used to predict the joint strength and the results were compared to the experiments for validation. The joints’ behaviour was highly dependent on α, and CZM were validated for the design process of hybrid scarf joints.
- Improving efficiency in a hybrid warehouse: a case studyPublication . Freitas, Andreia M.; Silva, F.J.G.; Ferreira, Luís Pinto; Sá, José Carlos; Pereira, Maria Teresa; Pereira, J.Logistics has assumed a determining position in the supply chain of each organization. This paper concerns the work carried out in a bus manufacturing organization with the aim of improving efficiency in its hybrid warehouse. A hybrid warehouse could be considered as one that mixes several different activities (reception, storage area, picking, shipping, supply to production lines and production preparation tasks) and brings together many different materials or raw materials and components. This factor led to the appearance of innumerable management methods to improve employee performance. These are intended to meet the needs of their customers, from the motto "do more with less". The work developed in a hybrid warehouse allows to detect logistic complaints related to communication failures between employees, the reduced efficiency in the activities like the check of raw materials or components and respective picking, the lack of space for their reception and storage, and the non-compliance of the FIFO stock management system. It is imperative that organizations can redefine internal spaces and flows, generating a more efficient and intuitive work and admit an opportunity for improvements in terms of space and content management, and hence, cost savings for an organization. The combination of Lean tools was implemented, and the results have been checked, showing a significant impact in the hybrid warehouse, with annual gains through the optimization of several activities: employee turnover (decrease by 50%), check and picking times (decrease about 75 minutes/picking) and better working conditions for employees.
- Improving the Mechanical Strength of Ductile Cast Iron Welded Joints Using Different Heat TreatmentsPublication . Marques, Eva S.V.; Silva, F.J.G.; Paiva, Olga C.; Pereira, António B.The main advantage of welding cast iron is to recover parts by repairing defects induced by casting processes (porosities, etc.), before they enter their working cycle, as well as repair cracks or fractures when already in service. This method contributes to decreased foundry industrial waste and avoids the additional energy costs of their immediate recycling. Therefore, it is necessary to have a welded joint with similar or better characteristics than the parent material. The major problem of welding cast iron is that this material has a very high content of carbon in comparison to steel (≈3%). Therefore, when it is heated by the very high temperatures from arc welding and during its process of solidification, very hard and brittle phases originate, known as ledeburite and martensite, and appear in the partially melted zone and in the heat-affected zone. Eventually, this problem can be solved by implementing heat treatments such as preheat or post weld heat treatments under specific parameters. Therefore, in this study, the aim is to collect data about the effects of heat treatments performed at different temperatures on welded joints of high strength ductile cast iron (SiboDur® 450), and to evaluate the effects of heat treatments performed at diverse temperatures on welded joints of this type of material, using Shield Metal Arc Welding and nickel electrodes. Mechanical strength, hardness, and microstructure were analyzed, showing that the best mechanical strength in the joint (380 MPa) was obtained using two passes of E C Ni-Cl (ISO EN 1071:2015) filler metal and post weld heat treatments (PWHT) of 400 °C for two hours.
- Acrylic adhesives in the polyolefins joiningPublication . Pinto, A. M. G.; Magalhães, A. G.; Silva, Francisco J. G.; Baptista, A. P. M.The mechanical behaviour of single lap adhesive joints was characterized, using two commercial acrylic adhesives. For this purpose the surfaces were cleaned and abraded using fine grit abrasives. The effect of temperature and moisture in the mechanical strength was, also, evaluated. For this characterization, mechanical tests were carried out according procedure and geometry foreseen by ASTM D3163-01 [1] and ASTM D4501-01 [2] standards. The results show that it is possible to get good strengths without great surface preparation. The temperature and moisture effect observed don’t seem to be relevant for the mechanical behaviour.
- Rheological Behaviour of PP Nanocomposites by Extrusion ProcessPublication . Almeida, F. De; Silva, E. Costa e; Correia, A.; Silva, F.J.G.The effect of organophilic clay (C15A) in PP compatibilized polymer (PP/PP-g-MA) through rheological experimental results is presented. This study focusses on the description of the rheological behaviour of the organophilic layers along the screws of a twin screw extruder by melting process, varying the screw profile as well as the processing conditions, namely screw speed, temperature and feed rate. Different levels of dispersion were found along the screws for all conditions and positions analyzed by rheology. The qualitative analysis of the images obtained by transmission electron microscopy, reinforced the results. Furthermore, the effects of the processing conditions on dispersion of C15A layers along the screw profile are analyzed using multiple linear regression techniques. The results show statistically significant differences of all rheology measures for all the processing conditions and positions along the extruder.
- Guidelines for Machine Tool Sensing and Smart Manufacturing IntegrationPublication . Costa, S.; Silva, F.J.G.; Campilho, R.D.S.G.; Pereira, Maria TeresaNowadays the Industry is becoming increasingly competitive with the emergence of even more advanced technologies. This environment leads the companies to look for a bigger availability of the assets, a higher quality of the products and consequently less costs. Thus, is because of this purpose that Maintenance is becoming even more fundamental. The focus of this paper was to develop a strategy of Predictive Maintenance on a Machine Tool with the aim of reducing the unplanned stops, increasing the productivity and creating the bases for an Industry 4.0 environment in the short term. Thus, a model has been created in order to fulfil this goal. The first step was the selection of the critical component of the machine tool that would be studied. In the next phase the variables that will be monitored were selected and their trigger limits. Finally, the necessary components to monitor this system were chosen. In order to reach the objective, a system of condition-based maintenance where the acoustic emissions and vibration of the bearing of a machine tool were monitor was proposed.