Key Engineering Materials Vol. 615

Abstract: Unstable technological and organisational conditions, in which nowadays organisations function, create a formation of new kinds of risk in their activity. In this scope the necessity of risk management should be noticed. It should allow for risk minimisation or elimination, finally resulting in processes’ continuity assurance. Risk management - connected with all processes in the organisation - must be realised as the system solution and undergo the improvement by the assessment, monitoring, measurement and analyses of risk. The suggested methodology of identification, analyses, assessment and acceptability evaluation determines the manner of risk undertaking. In accordance with the proposed procedure it can have character of operational control or system risk monitoring.

Abstract: This paper is an accomplished investigation in a main industrial group of the city of Altamira, México, as part of a program of improvement of the labor productivity in the area of construction and maintenance of Aguila Industrial Group. The research focuses on the development of a methodology to assess the labor productivity of the industrial maintenance projects. In the methodology, we propose the use of a work sampling tool in order to identify the main factors that affect labor productivity as well as we proposes apply lean manufacturing tools to improvement labor productivity. In the paper, we discuss the implementation findings of the developed methodology as well as the preliminary outcomes of the main factors affecting labor productivity in the construction and maintenance industry; such outcomes provide a guide in the labor productivity management in one of the sectors that exhibits less development grade in most of the Latin-American countries.

Abstract: Manufacturing systems need to integrate information from several sources, manage their business processes and coordinate the shop floor in order to meet the schedule at reduced costs. Holonic manufacturing has been proposed to solve these problems and has been normally implemented using agents. However, these implementations are not widely used due to their cost and limited interoperability. In this work, an approach that combines a service-oriented architecture with a multi-agent system is proposed. A list of rules is designed for deciding how to implement each holon, and is applied to the level 3 activities of ISA-95. The adoption of an enterprise service bus is suggested for decoupling service consumers and producers, and using a complex event processing engine is recommended to detect trends from the day-to-day operations of a plant. This approach is then applied to a grinded ceramic tile manufacturing plant, deriving a general architecture and an implementation of a service-based holon based on the ISA-95 object model, with a human-facing side (a website) and a machine-facing side (a Web Service).

Abstract: This paper shows a first approach to incorporate virtual elements (based on virtual reality) in an existing Flexible Manufacturing System (FMS). It suggests the main methodological ideas to develop a control system for a hybrid FMS where both, virtual and real elements, can work together. The paper starts from an existing FMS named CFF-ETSIA and implanted in the Aerospace Engineering School. A modular design is proposed towards the independence between the FMS elements so that the system flexibility increases. Virtual devices are created in order to reproduce the behavior of their real-homonymous elements as far as possible. This includes not only the mechanical way but and the behavioral way.

Abstract: Nowadays, there are a large variety of Compressive Forming Processes with different typologies and characteristics. These processes look to manufacture workpieces in the manner more efficient and economic possible. In this paper, the indentation process is studied from the point of view of manufacturing. The influence of technological parameters such as friction and shape factor on the process has been studied. The aluminum alloy AA 6082 has been employed in this study due to its good mechanical properties, light weight and its capacity of being recycled. The Finite Element Method (FEM) has been used for the analysis. The indentation process has been studied under axisymmetric conditions. As results, the forces to carry out the indentation process and the contact pressures have been obtained. Finally, it is shown that the forces and the contact pressures do not have a high dependency on the friction between the surfaces of the punch and the workpiece. The other hand, it is displayed that the shape factor has a greater influence on the process, especially the width of the workpiece.

Abstract: A new practical application for teaching mechanism calibration to engineering students in senior undergraduate courses is presented in this paper. The modelling, characterization and calibration of kinematic mechanisms is performed. This application presents a special interest in kinematic mechanisms in areas such as industry and research. The application interface allows the students to carry out the different steps of the calibration procedure in an easy way, to change different variables and to analyze results. This application therefore presents an important utility as a teaching tool for the learning process and analysis of the different steps in the mechanism optimization. The application developed allows students: to design their own mechanisms and to analyze the mechanism workspace by changing some design parameters, to test accuracy and repeatability of mechanism components, to introduce the mechanism kinematic model, to evaluate the mechanism performance before calibration, to calibrate the mechanism and, finally, to analyze the improvement in the system accuracy.

Abstract: This paper presents a new virtual environment aimed to the realization of dimensional metrology practices, in the framework of the Degree in Mechanical Engineering of Technical University of Madrid. The development of this project allows the implementation of an interactive teaching model, focused on the student, which combines master classes and virtual applications, in an environment known as DE–learning (driven e-learning). This teaching tool directs and helps students on an individual way in the dynamic and interactive practice development. In particular, this module simulates the functioning, calibration and measurements using a horizontal coordinate measuring machine (HCMM). The program interface has been developed trying to create an easy-to-use environment for the students, in order to be a first contact with the HCMM and its possible metrological applications.

Abstract: Subjects with manufacturing processes contents are part of most engineering degrees. These subjects are usually taught in halfway semesters and are of theoretical and practical nature. Very often students show problems to understand and retain the contents of these subjects, since most of those contents are frequently new and have not been addressed during secondary school. In this work, a study on students' level of comprehension and retention of manufacturing processes contents is presented. In order to analyze the learning process in the short and medium term, undergraduate and postgraduate students have been chosen. Moreover, possible lack of previous knowledge, degree of comprehension and retention and influence of the teaching modality (theoretical or practical) are also explored.

Abstract: The results of this paper suggest that there is a serious problem in the curricula definition of some degrees. It is necessary to analyze the educational activities, teaching methodologies and evaluation systems for the Bachelor’s and Master’s degrees at the institutional level. This will allow for improvements in the evaluation of competence acquisition. Therefore, it is necessary to review the definition of the curricula while paying special attention to the relationship between competences and courses because the current study has detected notable discrepancies. The courses must be evaluated through competences or, more precisely, through the results of the learning process. This would considerably improve an evaluation model of the progress and results on the learning acquired by graduated students in terms of competences and would match what is established in the current regulation. When analysing the results for any two students, a simple comparison based on grades is not realistic, as it depends on the subjectivity of instructors and teachers during the grading process. By contrast, an evaluation based on competences is much more objective and comparable and would demonstrate which university reaches a better level of both general and specific competence achievement. The results of the aforementioned procedure are of interest to employers, enabling them to search and hire the best students in the desired field of study.