Catálogo de publicaciones - libros

In this article, a systematical approach that attempts to integrate conventional quality function deployment (QFD) and morphological analysis in terms of effective multi-professional collaboration (MPC) knowledge handling in product concept development is presented and illustrated. For this purpose, a MPC-enabled product conceptualization paradigm was established. It consists of four scrupulously interacting modules, namely, user needs elicitation module using means-end chain (MEC) technique, design knowledge interaction module using design knowledge sharing model, product concept clarification module integrating QFD with functional analysis technique, and optimal concept alternative module using multi-attribute evaluation model (MAEM) within morphological analysis. A case study on the design of eating assistive device for patients with cervical cord injuries is used to demonstrate the performance of the proposed approach. From the case study, the authors also illustrate the effectiveness of concept design prototype with remote collaborative product design communication platform and rapid prototyping system which were applied in collaboration.

“Design for X” is commonly regarded as a systematic and proactive designing of products to optimize total benefits over the whole product life span (fabrication, assembly, test, procurement, shipment, delivery, operation, service, disposal), and meet target quality, cost, performance and time-to-market. DFX involves different methodologies for product design and optimization (like Design for: Manufacturing, Assembly, Variety, Serviceability, Environment, Reliability, Utilization, etc.), which provide useful results, however, they address only specific aspects of product life-cycle. In addition, various perspectives for business economics can often drive to contradicted conclusions, what makes the evaluation of both technical feasibility and product profitability more difficult. In this paper the framework for DFX analysis was proposed. In the described solution, the various product life-cycle analysis strategies are integrated, and profit calculations relay on common denominator — the present value of net benefit. This approach allows covering of all phases of a product life cycle not excluding e.g. complex environmental aspects. Based on the proposed framework, the DFX Platform was developed and implemented as a web service. The application of the system to a few product developments carried out within cross-bordered manufacturing company showed its big positive impact on projects and their results.

Lean Manufacturing philosophy has had an important role in productivity improvement in first rate industries. It came from the best practices applied by the Japanese automotive industry, targeting high quality, low cost, lower lead time and enhanced flexibility. Due to high competitiveness, there has been a great effort in its wider application. While product concept has had an important role on the efficacy of manufacturing, it must be said that there is still a shortage of elements for a proper product development with focus on Lean Manufacturing philosophy. Concern to design products that maximize specific characteristics by way of Simultaneous Engineering gave birth to DFX tools such as DFM. To this date no DFX tool has come up with enough subsidies to generate products that will support implementation of Lean as a whole. On the other hand, Simultaneous Engineering has not been used so as to involve Product Design with Lean Manufacturing. Present article proposes a set of guidelines, called Design for Lean, to systematize best practices for product development with focus on Lean Manufacturing through Simultaneous Engineering. They will target conceptual and detailed design phases. Email: marceloraeder@yahoo.com.br

Nowadays manufacturing companies are facing the challenge of meeting increasing specific customer needs and even so, to offer short delivery times and low price products. Companies must have flexibility to customize products in a rapid way. A product customization strategy, named “Postponement”, has been adopted by a growing number of companies to address the products’ differentiation requirements, demanded by the new global market. This paper aims to contrast and compare a proposed postponement strategy definition method with existing postponement approaches found in the literature. The paper reviews various approaches from different authors, to identify how postponement is described in terms of its benefits, implementation barriers, factors that enable or make difficult its practice and the relationship with other theories and techniques. The paper then highlights the contribution given by a proposed method to plan and implement the postponement strategy in a company, using a concurrent engineering perspective.

This paper outlines neural network non-linear models to predict moisture in real time as a virtual on line analyzer (VOA). The objective is to reduce the moisture variability in a continuous neutralization reactor by implementing a model-predictive control (MPC) to manipulate the water addition. The acid-base reaction takes place in right balance of raw materials. The moisture control is essential to the reaction yield and avoids downstream process constraints. The first modeling step was to define variables that have statistical correlation and high effect on the predictable one (moisture). Then, it was selected enough historical data that represents the plant operation in long term. Outliers like plant shutdowns, downtimes or non-usual events were removed from the database. The VOA model was built by training the digital control system neural block using those historical data. The MPC was implemented considering constraints and disturbances variables to establish the process control strategy. Constraints were configured to avoid damages in equipments. Disturbances were defined to cause feed forward action. The MPC receives the predictable moisture from VOA and anticipates the water addition control. This process is monitored via computer graphic displays. The project achieved a significant reduction in moisture variability and eliminated off-grade products.

Initially, when implementing a design automation system the focus is on successfully developing a system that generates design variants based on different customer specifications, i.e. the execution of system embedded knowledge and system output. However, in the long run two important aspects are the modelling and management of the knowledge that govern the designs. The increasing emphasis to deploy a holistic view on the products properties and functions implies an increasing number of life-cycle requirements. These requirements should all be used to enhance the knowledge-base allowing for correct decisions to be made. In a system for automated variant design these life-cycle requirements have to be expressed as algorithms and/or computational statements to be intertwined with the design calculations. The number of requirements can be significantly large and they are scattered over different systems. The aim of the presented work is to provide an approach for modelling of manufacturing requirements, supporting both knowledge execution and information management, in systems for automated variant design.

It is proposed in this paper the on-line adaptation of process plan with alternatives, through the application of an operation-based time-extended negotiation protocol for decision-making about real-time routing of job orders of parts composed of machining operations in a job-shop environment. The protocol is modified from the contract net protocol to cater for the multiple tasks and many-to-many negotiations. The grouping of the machining operations enables reduction of setup times, resulting from the reduction of machines changes. For each part, all feasible routings are considered as alternative process plans, provided the different manufacturing times in each machine are taken into account. The time-extended negotiation period allows the visualization of all of the times involved in the manufacture of each part, including those times that are not considered in systems of this nature, such as the negotiation times among agents. Extensive experiments have been conducted in the system, and the performance measures, including routings, makespan and flow time, are compared with those obtained by the search technique based on the co-evolutionary algorithm.

In recent decades industry has focussed a lot of attention on changeover performance, recognising it has to reduce changeover losses in multi-product manufacturing environments in order to remain competitive.

This paper seeks to analyse the complexity of the changeover problem and the scope of the diverse improvement opportunities which typically are present. It does so by investigating widely variable changeover classification methodologies which have been developed to date. The paper discusses how suitable elements of these existing methodologies might be combined, thereby guiding the changeover practitioner in a structured fashion to consider a full compliment of potential improvements.

In the museum visitor routing problem, each visitor has some exhibits of interest. The visiting route requires going through all the locations of the exhibits that he/she wants to visit. Routes need to be scheduled based on certain criteria to avoid congestion and/or prolonged touring time. In this study, museum visitor routing problems (MVRPs) are formulated by mixed integer programming and can be solved as open shop scheduling (OSS) problems. While visitors can be viewed as jobs, exhibits are like machines. Each visitor would view an exhibit for a certain amount of time, which is analogous to the processing time required for each job at a particular machine. The traveling distance from one exhibit to another can be modeled as the setup time at a machine. It is clear that such setup time is sequence dependent which are not considered in OSS problems. Therefore, this kind of routing problem is an extension of OSS problems. Due to the intrinsic complexity of this kind of problems, that is NP-hard, a simulated annealing approach is proposed to solve MVRPs. The computational results show that the proposed approach solves the MVRPS with a reasonable amount of computational time.

New product development (NPD) is a critical process to improve a company’s competitiveness. As environmental impacts generated throughout the product lifecycle are significantly determined during the early phase of its development, NPD plays a crucial role in enhancing the environmental performance of new products. Ecodesign may be defined as the systematic introduction of environmental concerns during product development. Despite the fact that several opportunities for competitive advantage have been associated to ecodesign the implementation of this concept has not reached companies worldwide mainly due to the gap between eco-oriented and product-oriented research. Thus both points of view must come together in order to achieve ecodesign benefits. This paper aims at proposing a systematic approach to do it by introducing some selected ecodesign methods and tools into the early phases of a reference model for NPD. The expected result is a set of structured activities that can successfully combine ecological and business perspectives. This paper presents some preliminary results on the field of sustainable product development (SPD) conducted by the authors.