Elsa Henriques

Influence of silicon powder-mixed dielectric on conventional electrical discharge machining

Electrical discharge machining (EDM) is a technological process with a large industrial implementation. Its use is particularly intense when very complex shapes on hard materials with a high geometrical and dimensional accuracy are required. However, the technological capability of the process has limited its application when the specification of the part surface quality imposes polished and mirror-like characteristics. The addition of powder particles in suspension in the dielectric modifies some process variables and creates the conditions to achieve a high surface quality in large areas. This paper presents a new research work aiming to study the performance improvement of conventional EDM when used with a powder-mixed dielectric. A silicon powder was used and the improvement is assessed through quality surface indicators and process time measurements, over a set of different processing areas. The results show the positive influence of the silicon powder in the reduction of the operating time, required to achieve a specific surface quality, and in the decrease of the surface roughness, allowing the generation of mirror-like surfaces.

Creativity enhancement in a product development course through entrepreneurship learning and intellectual property awareness

Product development is the set of activities starting with the perception of a market need and ending in the production and sale of a new product satisfying that need. Broadly speaking, it is a process that should follow a structured methodology, if a certain level of effectiveness and efficacy is envisaged. In the Portuguese industrial environment, there is, in general, a weak perception of this methodology. Even when this perception exists, it is hardly integrated with the companys culture and related processes. In university engineering degrees curricula, there is very little integration of interdisciplinary knowledge that leads to a global understanding of what engineering and product development integrated with entrepreneurship issues should be. This work presents an integrative approach to bridge this gap between industry and university by the teaching of a course on product development and entrepreneurship, at a graduate level. Special attention is given to innovation and creative thinking during concept development, through the introduction of a structured method to promote it, and to the appeal of intellectual property rights to motivate innovative thinking among students. Teaching product development integrated in an entrepreneurship framework promotes students skills in what it takes to start a new business and makes them feel comfortable in executing the idea-to-product viability evaluation in a business perspective.

Best practices of collaboration between university and industrial SMEs

Purpose – The purpose of this paper is to contribute to the implementation of best practices of collaboration between university and industrial small‐ and medium‐sized enterprises (SMEs).Design/methodology/approach – This paper presents the experience carried on by a university group fostering the collaboration with SME companies involving young engineering students and researchers in projects designed for the resolution of real industrial problems. A collaboration model is proposed and described. Four real case studies are presented.Findings – The purposed model promotes the involvement of the young engineers with authentic industrial experiences, enables the build‐up of their practical framework and encourages their entrepreneurial growth. It also promotes the innovation process in SME companies through the close collaboration with universities.Practical implications – The collaboration between universities and SME companies should be based on a small projects base. These projects must be focus in local...

An architecture to support the manufacturing system design and planning

This paper presents research work that is aiming to extend an existing architecture that integrates Virtual Reality (VR) capabilities with simulation and engineering tools for remote collaboration. Based on the work performed at an Engineering Centre, closely linked to industry, a couple of examples that are developed in real manufacturing contexts are described and discussed. The discussion justifies a step forward for an advanced engineering platform targeted to typical small- and medium-sized companies, supporting collaborative work, sharing experience and best practices between several geographically dispersed engineering teams. For companies with a lack of advanced engineering expertise and resources, the expected links that the engineering platform will promote have a significant impact upon the continuous improvement process.

Assessment of Energy Consumption in Injection Moulding Process

Injection moulding may appear to be a benign process regarding energy consumption. However, the large scale of this process makes its impacts especially critic and minor efficiency improvements may lead to high overall energy savings. Moreover, energy consumption affects not only the product manufacturing costs, but is also a critical component in any overall sustainability strategy. This paper presents a model that estimates in an early phase of the design of a plastic part the energy consumption during its manufacturing. This enables estimating the energy consumption for different part geometries and different machines and process conditions prior to the production phase. Moreover, this paper contributes in integrating thermodynamic fundamentals and empirical relations fostered by literature review and an experimental analysis developed in an injection moulding company. In the end the thermodynamic/empirical model is validated by comparing its results for several parts with the measured real energy consumption.

Teaching Design in the First Years of a Traditional Mechanical Engineering Degree: Methods, Issues and Future Perspectives.

Engineering design is known as an answer to an ill-defined problem. As any answer to an ill-defined problem, it can never be completely right or absolutely wrong. The methods that universities use to teach engineering design, as a consequence of this, suffer from the same fate. However, the accumulated experience with the ‘chalk and talk’ teaching tradition has led to a reality in which the employers of fresh graduates are not happy with the engineers they are getting. Part of their complaints are related with the inability of recently graduate engineers to work in problems where the boundaries are not well defined, are interdisciplinary, require the use of effective communication and integrate non-technical issues. These skills are mostly absent from traditional engineering curricula. This paper demonstrates the implementation of engineering design perspectives enhancing some of the aforementioned skills in a traditional mechanical engineering curriculum. It emphasises in particular a design project that is tackled in a sequence of conventional courses with a focus that depends on the course objectives and disciplinary domain. This transdisciplinary design project conveys the idea (and effectively implements it concurrently) that design is multidisciplinary.

Comparative case study of life usage and data-driven prognostics techniques using aircraft fault messages

Abstract Prognostics are a key activity in repair and maintenance operations. A recent approach to condition-based maintenance is the data-driven approach. This approach has been mostly based on past failure time measures, and sensed measurements of component degradation to derive estimates of the remaining useful life of equipment. An alternative source of data, rarely used in these models, is the stream of automatic messages derived from diagnostics systems, which consist of fault codes indicating abnormal events or deviations from optimal operation. Despite the richness and concise nature of these messages, their difficult interpretation poses significant challenges to its use in prognostics. This paper aims to show that data-driven prognostics based on this type of messages can be better suited to maintenance than time-based approaches. We illustrate this comparison with an industrial case study involving the removal times of a bleed valve from the aircraft air management system. Our experimental results reveal a significant accuracy improvement over the contrasting time-based models. We also establish the contribution to this improvement of the data-driven methods and message-related predictors.

Application of Life Cycle Engineering for the Comparison of Biodegradable Polymers Injection Moulding Performance

The use of biodegradable and compostable polymers (BDP) has a rising concern derived from its particular characteristics. Currently, various BDPs are combined to improve technical performance, to open up new applications or to reduce costs. In this paper a Life-Cycle-Engineering model is developed to compare the economical, environmental and technical dimensions of performance for 4 different types of BDPs when processed through injection moulding technology. The proposed model allows for comprehensive alternative comparison, supporting informed material selection decisions in a product-design context. The use of a ternary decision space supports materials comparison and the identification of their ‘‘best alternative domains’’.

Forecasting fault events for predictive maintenance using data-driven techniques and ARMA modeling

Abstract Presently, time-based airline maintenance scheduling does not take fault predictions into account, but happens at fixed time-intervals. This may result in unnecessary maintenance interventions and also in situations where components are not taken out of service despite exceeding their designed risk of failure. To address this issue we propose a framework that can predict when a component/system will be at risk of failure in the future, and therefore, advise when maintenance actions should be taken. In order to facilitate such prediction, we employ an auto-regressive moving average (ARMA) model along with data-driven techniques, and compare the performance of multiple data-driven techniques. The ARMA model adds a new feature that is used within the data-driven model to give the final prediction. The novelty of our work is the integration of the ARMA methodology with data-driven techniques to predict fault events. This study reports on a real industrial case of unscheduled removals of a critical valve of the aircraft engine. Our results suggest that the support vector regression model can outperform the life usage model on the evaluation measures of sample standard deviation, median error, median absolute error, and percentage error. The generalized linear model provides an effective approach for predictive maintenance with comparable results to the baseline. The remaining data-driven models have a lower overall performance.

Assisting Mould Quotation Through Retrieval Of Similar Data

Moulds are complex devices and their quotation is one of the most risky tasks in mould industry. In this paper a digital work environment based on a computer assisted mould quotation tool is proposed in which all the relevant information is quickly available to assist a robust and rapid quotation. The tool involves a new way to directly access past quotation, design and even manufacturing data based on the similarity of mould geometry and mould attributes. It applies new 2D/3D design concepts where sketches and text attributes are used to search for and access similar moulds. The main results from the analysis of mould quotation procedures and a preliminary tool prototype are presented.