Repositório RCAAP

Manual 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.

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.

Competitiveness has been the key factor for the survival of the companies. The economic crisis that marked the beginning of this millennium forced the total readjustment of processes and operations which, in some cases, gave origin to deep changes in the organizations. In addition, concerns and consequent environmental constraints have begun to increase. Printing industry was strongly influenced by these factors. This study aims to reduce the use of toxic products and general costs in offset printing process, as well as promote a productivity increase in the printing industry. Because this kind of industry is largely influenced by weather conditions, historical data was collected, allowing to reach the balance between the printing consumables usage and working methodologies, leading to implementing important improvements. At the end of the study, it was possible to observe very good results, increasing the Overall Equipment Effectiveness (OEE) and the Mean Time Between Failure (MTBF) and reducing the Mean Time To Repair (MTTR) relatively to the equipment. The biggest achievement was the massive reduction of the isopropyl alcohol consumption in the offset printing process, increasing the air quality at the facilities, reducing the costs and most of the problems during the printing process.

The increasing requirements regarding quality assurance and processes traceability require the implementation of continuous improvement procedures, with a view of maintaining the company’s levels of competitiveness and satisfaction for its customers in terms of quality. The optimization of information flows and manufacturing processes are, in general, extremely important factors in any company’s life. It is therefore important that companies quickly self-adapt to this kind of reality and adopt policies of product innovation and standardization of its production processes, in order to allow rapid adaptation to the constant market changes. The present work aims to identify problems and finding solutions through a combination of PDCA (Plan-Do-Check-Act) cycle, 5S (Seiri, Seiton, Seiso, Seiketsu, Shitzuke) and 5W2H (5 Whys + 2 Hows) tools those can be implemented into a program of continuous improvement, with a view of standardizing of processes, ensuring real profits in products typically with critical added-value. The combination of tools was implemented and the results have been checked, showing a significant impact in the Weaving production process, with gains of 10% in the useful available time by the operator.

The painting activity is one of the most complex and important activities in automobile manufacturing. The inherent complexity of the painting activity and the frequent need for repainting usually turn the painting process into a bottleneck in automobile assembly plants, which is reflected in higher operating costs and longer overall cycle times. One possible approach for optimizing the performance of the paint shop is to improve the efficiency of the color planning. This can be accomplished by evaluating the relative merits of a set of vehicle painting plans. Since this problem has a multicriteria nature, we resort to the multicriteria decision analysis (MCDA) methodology to tackle it. A recent trend in the MCDA field is the development of hybrid approaches that are used to achieve operational synergies between different methods. Here we apply, for the first time, an integrated approach that combines the strengths of the analytic hierarchy process (AHP) and the Preference Ranking Organization METHod for Enrichment Evaluations (PROMETHEE), aided by Geometrical Analysis for Interactive Aid (GAIA), to the problem of assessing alternative vehicle painting plans. The management of the assembly plant found the results of value and is currently using them in order to schedule the painting activities such that an enhancement of the operational efficiency of the paint shop is obtained. This efficiency gain has allowed the management to bid for a new automobile model to be assembled at this specific plant.

Education for Sustainable Development (ESD) addresses sustainable development issues, in the economic, environmental, and social dimensions. The positive role of higher education institutions (HEIs), such as Universities and Polytechnic Institutes, in educating decision makers and leaders, and therefore contributing to progress and the public good, has been widely acknowledged. This investigation aims to map the BSc and MSc courses offered by Portuguese HEIs that address Sustainability (or Social Responsibility, or Ethics) in their curricula with the aim of proving their graduates with the right knowledge and competencies to overcome the Sustainable Development challenges. A systematic review utilizing a structured approach was used to analyze Portuguese HEIs BSc and MSc courses and the content analysis of their curricular units. The conclusions show that Sustainability (or Social Responsibility, or Ethics) is covered in most Social Sciences, Engineering, and Management, BSc and MSc courses, offered by the top 8 Portuguese Higher Education Institutions. However, ESD is fragmented by different approaches, issues, methodologies, and implications, lacking a consistent body of knowledge. Some courses focus more on the Social dimension, while others are more directed to the Environment or the Economic one. Sometimes the chosen approach is more normative (do what is right to do; the ethical way) and in other cases is more instrumental (do what is good for the business; the business case). Social Sciences, Engineering and Science, and Management and Economics are the three top clusters that address Sustainability related syllabus in their curricula, with 49 hours teaching hours in average for the curricular units covering Sustainability (with considerable variation). Universities have more curricular units addressing the topic while Polytechnic Institutes show a higher number of hours per curricular unit and most are of compulsory nature (while in Universities more than 50% of the curricular units are of optional nature). As the collected information was in some cases of generic nature, additional research should be used to confirm and detail these results and evaluate the effectiveness of this education to empower students to act as change agents for Sustainable Development. Benchmarking with other countries (e.g., from the European Union) is also an interesting avenue to pursue this investigation.

An empirical study of more than 300 Portuguese organisations ISO 9001 certified, or in certification process, encompassing a wide range of activities sectors, was carried out. As of May 2017, 19% of the respondents already have ISO 9001:2015 certification and all the remaining one’s plan to complete the process in time. The principal reported benefits are risk-based thinking, mapping of the organisational context, and stakeholder identification. Simultaneously those were the issues that required more attention and effort to be mastered and implemented. Additionally, there is evidence that ISO 9001:2015 enhances both internal and external organisational issues and generates benefits for all the researched dimensions. Based on the respondents’ responses, organisations who claimed that external motivations were the primary drivers to ISO 9001:2015 implementation systematically rate higher all the benefits when compared with the rating ascribed by those organisations who claimed internal motivations. Moreover, it is possible to conclude that the perceived benefits from ISO 9001:2015 implementation and certification seem to be strongly influenced by two primary dimensions: the (smaller) organisation size and the (lesser) international presence.

This paper describes a software, developed in PROLOG, called ISEPCPC (Intelligent System for Electric and Pneumatic Control of Pneumatic Circuits). It uses PROLOG clauses, Artificial Intelligence (AI) techniques (an Expert System), and Karnaugh Map’s methodology. The main objective is to compute the set of optimized logic equations that enables either an electric or a pneumatic control of any, but mainly complex pneumatic circuits. As the complexity of the circuit increases, as the result of a combinatorial explosion generated by the increase in the number of cylinders involved, the more difficult it becomes to obtain the control equations (often requiring the use of auxiliary memories). This software automatically obtains the equations which will yield minimized circuit configuration. These equations, can be used either in electro or pneumatic control. A practical application example of the software will be shown to prove its applicability. The minimum number of equations required to control the circuit will be used in programming a PLC that will control the circuit.

The IEC 61499 standard defines a framework for the development of distributed control applications, including a modeling language and its associated execution semantics. Traditionally industrial control applications run on a single computing device. When moving to a distributed solution new failure models need to be taken into account. In previous work the authors have this proposed a framework to support the development of fault tolerant distributed IEC 61499 applications, based on the use of active replicas. Special communication protocols were considered in order to guarantee replica determinism and synchronization. In this paper we relax the replica determinism requirement and explore other possible implementations for the replication framework that do not require special communication protocols and are easier to implement in practice.

Occupational Health and Safety (OHS) is a set of activities to prevent injuries and health problems to workers and to provide safe and healthy workplaces (ISO 14001:2015). According to the International Labor Organization (ILO), more than 2.3 million people lose their lives each year in their professional activities and more than 300 million work-related accidents occur. The impact on companies is significant and most of these accidents could have been avoided. Thus, it is necessary that they address health and safety at work in a systematic and integrated way. Given the relevance of ISO International Standards, the International Organization for Standardization (ISO) has created a Project Committee consisting of a team of specialists in OHS to develop ISO 45001 - Occupational Health and Safety management systems - requirements, which was published in 2018. Among the benefits that ISO envisage will come from the implementation of ISO 45001:2018, some issues assume higher importance, such as increased productivity, reduction of costs of stoppages and losses of production, reduction of costs with insurance and lost work days, improvement of the quality of products or services, among others. This work aims to characterize the Portuguese reality, regarding the relevance given to OHS, independently of the sector of activity or size of the companies. Approximately 500 companies (certified and uncertified) were invited to participate through an online survey, with open and closed questions. After processing the data from the 94 valid responses, it was possible to conclude that 98% of these companies are aware of the benefits that OHSMS provides or could provide. Also, 75% of them comply with ISO 45001 requirements, namely concerning the establishment and monitoring of measurable annual targets for OHS, the implementation of the risk prevention program and internal audits to evaluate OHS concerns.

This paper presents an alternative way to use the Karnaugh maps, which minimises logical conditions used for ON/OFF control, in either pneumatic and electro pneumatic circuits. In the last case, the methodology allows the control of the circuit through a programmable logic controller (PLC). In this kind of processes, controlling pneumatic cylinders is a problem that not only depends on the state of the information present but also in terms of knowledge of past actions. In practice, ensuring a series of sequential movements in an automatic cycle is to find the set of equations that should be executed to ensure the realisation of the desired sequence. It means therefore that the equations that will allow the movements of each cylinder are functions only of two types of input variables, the position of each cylinder and if necessary, memory variables. One of the major merits that arise from the use of the proposed method is the simplicity of obtaining electrical schematic command circuit. The proposed methodology ensures not only the desired sequential cycle, as well as the minimisation of the variables necessary for control commands.

Logistics is an important area in the economic-financial performance of companies, which makes it necessary to analyse their costs, as well as the trade-offs between them. Thus, the present study, with the objective of analysing the Portuguese food sector logistic professionals’ knowledge regarding to logistics costs trade-offs and their impact on the economic-financial performance of the organizations, showed that there are gaps concerning this subject. Throughout the structured interview and by using the SPSS software, the study shows the existence of flaws in the practical application of the trade-offs’ theory, such as the pressure from the managers for individual cuts in costs; and points out trade-offs of logistical costs relevant to the food sector. These results contribute to the expansion of studies on the subject, besides providing a perspective of the compensatory exchanges that can contribute to the decision making in relation to the costs concerning logistics activities.

Global competitiveness, mainly in the automobile sector, requires a constant focus on products and process innovation in order to provide consumers with a large variety of products of an excellent quality and at a low cost. In line with this philosophy, the study undertaken of the work method and its inherent activities has pointed to time measurement as a support tool of great potential in the optimization of the production process. The present case study aims to optimize the production process of an assembly line dedicated to the manufacture of control cables for the automotive industry. The ultimate objective was to adjust the output of the current line to that of the initial budget. By mapping all the activities and measuring the time spent on each of these, one was able to analyze the existing problems and inefficiencies. Subsequently, through the use of Lean tools and methodologies, one managed to find viable solutions, which resulted in a significant increase in productivity. The solutions implemented have allowed for an increase in line output of 43%, thus setting it within the values considered in the budget. One also achieved a reduction of 30% in assembly line use, which allowed for the addition of new product references on the assembly line in question. Since these gains are considerable for the company, the same methodology was standardized so that it could be applied to other assembly lines.

This paper focuses on the quality costs analysis in the automotive industry, specifically a bus manufacturing company. The main goal was to improve the quality costs indicator, by providing means to evaluate the failure cost within the productive process. Kaizen-lean principles were used as methodology. A quality cost analysis was made based on literature review and in an ISO standard in quality costs. Process analysis was made based on the PDCA (Plan, Do, Check, Act) cycle. As the main achievements of this article, the quality costs were identified as well as its sources. Then, by collecting a very significant amount of data, from various departments, regarding each of the identified costs, it was possible to measure these costs and create a database to scorecard them – including rework costs. Due to the lack of rework costs information, a great part of this analysis focused on data collection and estimating/calculating these associated costs. Thus, it was possible to develop associated KPI’s (Key Performance Indicators) to support decision making and a graphic indicator to show the overall balance between quality costs and non-quality costs. In this process, some difficulties were found as well as some opportunities for improvement. The critical ones were implemented during this project, while the others are scheduled for future work. In terms of a more technological approach to these studies, some autonomous systems can exist, although it comes at a great cost. However, the 4.0 Industry concept is evolving and fits perfectly in the quality costs monitorization context: an integrated information system with a global data network allows for a quick check-up of all the quality costs, by category, while freeing employees from doing this work manually.

Modern industrial environment control programs are distributed among several devices. The IEC 61499 standard defines function blocks with which distributed control applications may be developed, and how these are interpreted and executed. Its functionality and the inherent support for dynamic reconfiguration provide the required infrastructure for Industry 4.0 and industrial IoT applications. However, by their distributed nature new challenges are posed, especially about how modes of failure are handled. To avoid system malfunctions and breakdowns due to partial failures, the authors propose a new framework were the concept of replication can be applied maintaining internal state synchronised. This paper presents an example of how the replication framework on the FORTE IEC 6499 execution platform can be developed and voting strategies, along with the results obtained in the implementation with the standard communication SIFBs available on the Eclipse 4diacTM.

Nos dias de hoje, com a informatização dos sistemas de informação, as organizações, a nível mundial, são capazes de armazenar todo o tipo de informação por elas gerada. Esta informação é cada vez mais complexa, podendo conter dados de produção, de consumo, de facturação, etc. Sem desprezar o resto da informação produzida, pode dizer-se que os dados administrativos assumem uma relevância especial na gestão dessas organizações. É sobre estes dados que as organizações baseiam todas as tomadas de decisão que definem o seu futuro num ambiente competitivo. Associados a toda a complexidade da informação gerada, estão os problemas de qualidade de dados, muitas vezes desprezados, mas que podem influenciar negativamente as medidas adoptadas e os objectivos traçados. Este capítulo procura, acima de tudo, chamar a atenção para este tipo de problemas, referenciando algumas das suas implicações no âmbito hospitalar. Como resultado, este capítulo apresenta uma sistematização dos vários erros possíveis de constar neste tipo de bases de dados administrativas, contribuindo com alguns exemplos encontrados durante um estudo de qualidade de dados.

Karnaugh map is a method to simplify a logical equation, or convert a truth table in the corresponding logic circuit. This paper presents an alternative way to use the Karnaugh maps that minimizes the logical conditions of command for pneumatic circuits, whether the command is pneumatic or electric. In the last case, the method also permits the control of the circuit through a programmable controller (PLC). In practice, ensure a series of sequential movements in an automatic cycle is to find the set of equations which are executed ensure the realization of the desired sequence. The application of the method itself becomes dispensable analysis of speed or course of the cylinders (irrelevant features to the materialization of the command sequence). It means therefore that the control cylinders equations that will allow his movements (called output variables) are function only of two types of variables (input variables), the position of each cylinder (end-of-stroke valves) and if necessary memory variables. The proposed methodology ensures not only the desired sequential cycle, as well as the minimization of the variables necessary for control commands. To simplify substantially the explanation of the method, it is assumed that each pneumatic cylinder is associated with two end-of-stroke valves for detecting its position. The description as well as the applicability of the proposed methodology will be illustrated using a concrete problem of industrial automation. The methodology described here, will extend its use not only in industrial applications, but also the educational level in terms of engineering schools allowing a particular use in the automation of laboratories in the field of pneumatic control circuits and sequential electro (it is currently teaching in automation course unit of mechanical engineering in ISEP).

The classic methodologies of electro-pneumatic control are essentially based on the Cascade method and a methodology supported by Karnaugh Map. If in the first method, the resolution of pneumatic problem is basically performed by dividing the working sequence in groups, in the second method, the approach is made by the minimization of the control logic equations converting the truth table, to the corresponding logical circuit. In this paper we present an alternative form of a PLC programming, using the Cascade and Karnaugh methods, replacing the classic technique supported by the Grafcet modelling.

This research applies game theory to analyse price-set competition between a nonprofit hotel and a for-profit (private) hotel, in a differentiated service market, with uncertain demand. The nonprofit hotel aims to maximize social welfare. We compute the Bayesian-Nash equilibrium, and we analyse the effects of the degree of the weight assigned to consumer surplus on market equilibrium outcomes. As a result, we get that as the nonprofit hotel values more the consumer surplus, both hotels set lower prices. Furthermore, the expected profit of the for-profit hotel decreases with the degree of the weight assigned to consumer surplus; and the expected profit of the nonprofit hotel decreases (resp., increases) with the degree of altruistic preference, for either low (resp., high) values of this degree. We also compare the results obtained with the ones when the nonprofit hotel aims to maximize the sum of its own profit with the consumer surplus (with some weight assigned to it).

The IEC 61499 was developed thinking about the new generation of distributed control and automation systems. This provides essential resources for the development of distributed systems such as encapsulation, portability and reconfiguration. In this sense, and to ensure confidence in the operation should be implemented fault tolerance techniques dealing with hardware failures and errors off software associated with us where the distributed application runs. In this paper, we propose an approach to deal with failures in distributed systems tolerance problems, based on a replication model based on replication software/hardware as a means to achieve confidence in the operation.