Mario Tucci

Layout Design for a Low Capacity Manufacturing Line: A Case Study

The layout re-arrangement of fashion production lines realizing many small batches is rarely deployed according to well-known engineering procedures. In fact, it would often appear too complex to call a plant engineer for the proper layout design of such small production lines. Rather, it is preferred to apply empirical methodologies when considering, generally, factory know-how, general business needs, safety requirements, and so on. In the present work, the results of a fashion manufacturing line re-layout were compared by analysing the current situation with the solutions provided by a “homemade” company design, both through a systematic layout planning approach and a broader lean reengineering activity. In order to evaluate the effectiveness of each solution, the different alternatives were compared with the help of a discrete event simulator, analysing productivity, transportation times and costs. The result of the case study showed a slight advantage with the lean approach in considering such efficiency indicators. In addition, the lean production methods allowed the designers to identify some inefficiencies that other approaches could not see, since the latter did not focus on production in a holistic way.

Bucket Brigades to Increase Productivity in a Luxury Assembly Line

One of the most challenging issues in manual assembly lines is to achieve the best balance of workloads. There are many analytic approaches to solve this problem, but they are often neglected, since they are time-consuming and require high level engineering skills. Fashion bags packaging lines must comply with a number of different products with low production volumes, while the organization of the line is often under the mere responsibility of the foreman, who balances workloads in an empirical way. The aim of this work is to evaluate the effectiveness of the arrangement of bucket brigades (BBs) for an assembly line of luxury handbags. To do this, it was decided to perform a testing activity in a company producing fashion handbags in order to compare the self-made design with the BBs and with a simple assembly line balancing problem algorithm. The originality of this research lies in the fact that there are no studies in the literature on BBs applied to the packaging of highly variable small batches. The results were excellent, showing the advantages of BBs in terms of flexibility, the reduction of work in the process and the ability to handle small anomalies.

Using simulation for supply chain analysis: reviewing and proposing distributed simulation frameworks

Simulation modelling and analysis can be an extremely effective tool for supply chain performance analysis. Many development proposals apply distributed simulation to this context. The aim of this paper is to present an overview of such standards, models and/or architectures, describing the technological choices related to each of them, and to propose how and when a distributed supply chain simulation framework is to be used. Our proposal includes brief examples and experiences from experimental researches. Though detailed implementation of the framework is not in the scope of this paper, references for further information are given. In order to provide a coherent presentation of the proposal, this paper will be organised as follows: Section 1 introduces the context of supply chain management. Section 2 shows how distributed supply chain simulation (DSCS) can be an extremely effective tool for performance analysis in supply chain planning and optimisation. Section 3 points out the available technologies and the technological aspects of a distributed simulation framework, such as inter-process communication (IPC) standards and real-time infrastructures. Section 4 describes how the DSCS framework can be utilised. Section 5 reports on framework validation and gives an outlook on the experimental researches. Finally, section 6 concludes the paper summarising the proposal and discussing its benefits and drawbacks.

Risk-based inspections enhanced with Bayesian networks

The present paper aims to assess the usefulness of the integration of a qualitative risk-based inspection (RBI) procedure with the modelling of Bayesian belief networks (BBNs). In such a way, qualitative RBI, usually performed following standard procedures, might still be applied, even with the lack of some necessary data. Another benefit of the proposed method is the capability to include new factors in the evaluation, overtaking the rigid structure of the procedure. The qualitative RBI was chosen for its simple and clear structure, while the choice of the BBN formalism was made because of its flexibility and power to represent discontinuous variables. Bayesian formalism, moreover, allows a quick and easy extension of the model with additional variables. As a result, a BBN modelling a qualitative RBI was constructed. In the network, all of the RBI variables were included, as well as new external variables. An application for a chemical plant was tested in order to prove that BBNs can profitably model qualitative RBIs and can go beyond its rigid structure with the addition of new variables.

Accelerated degradation tests for reliability estimation of a new product: A case study for washing machines

Accelerated degradation test is a valuable technique able to provide information on the duration of highly reliable products. It is widely used in electronics, where component life often cannot be estimated in an acceptable time with the classic reliability estimation techniques. In the mechanical engineering sector, however, accelerated degradation tests are not so common. The purpose of this study is to evaluate the applicability of accelerated degradation test methodology to a new mechanical subassembly of a washing machine. In particular, we tried to identify which was the most appropriate degradation parameter, choosing among three possible alternatives. The methodology was applied to the new oscillating group of a washing machine, with oversized dimensions and innovative materials. The first selection of elements that could be monitored initially provided three parameters: the drum deformation, the bearing temperature and the vibrations of the rotation shaft. The research allowed the identification of the deformation as the most appropriate parameter for the reliability estimation of the oscillating unit. The originality of this study lies in the fact that accelerated degradation tests of washing machines is not discussed in earlier studies. In addition, the application of such methodology to select the best from three different parameters is not studied earlier. In this study, another peculiarity of accelerated degradation test has been emphasized: it is possible to quickly enrich the know-how on a new product, allowing an in-depth knowledge of new elements, in far more rapid speed than using the traditional approach.

Accelerated life tests as an integrated methodology for product design, qualification and production control: a case study in household appliances

Cost reduction and product quality are key factors in the present competitive market. Product reliability is strongly correlated with customer satisfaction. Accelerated life tests (ALTs) represent a methodology able to investigate product reliability performance in a short time with respect to the classical testing methods in the design. The aim of this paper is the proposal and development of an integrated procedure based on ALTs in order to evaluate the reliability performance of a new product; the use of such testing methods is useful to systematically support the design and qualification phases and to help the service demand forecasting before the product launch. The smart choice of the acceleration parameter and the knowledge developed during the upstream phase in the product lifecycle can be useful and cost effective for its utilization in the downstream lifecycle, as an acceptable substitute of specific advanced final inspection methodologies. The methodology has been tested during the development of a new model of washing machine. The application of ALTs was able to stress one of the most important failure modes of the product, returning important validation data for the design phase and qualification phase and giving good expectation for its fruitful utilization for final inspection in production.

OEE Evaluation of a Paced Assembly Line Through Different Calculation and Simulation Methods: A Case Study in the Pharmaceutical Environment

Modern production systems must guarantee high performance. Increasingly challenging international competition, budget reductions for the health sector and constant technological evolution are just three of the many aspects that drive pharmaceutical companies to continuously improve the productivity of their lines. The scientific literature has for many years been proposing calculation models for estimating the productivity of a machine. One of the most famous, and still used, is overall equipment effectiveness (OEE). This allows the calculation the valuable output considering the six ‘big losses’. The limitations of this approach are noticeable when considering a production line instead of a single machine. Numerous researchers have proposed alternative methods or changes in OEE, to be able to cover the widest spectrum of possible cases. In this study, we wanted to evaluate how such theoretical models related to OEE are actually able to represent the world of tight production flows or whether, in these cases, a more complex type of simulation should be preferred. To do this, we carried out a case study of a production line in the pharmaceutical industry, and the results showed that the simulation approach gives better results because of the peculiarities not considered by the theoretical models.

New maintenance opportunities in legacy plants

Abstract Applying condition based maintenance may be the only way to keep the performance of many legacy plants high enough. Commercial applications for condition based maintenance might often be too rigid to be applied to older machines. Sometimes they can be extremely specialized for some families of products or in very specific fields of application. In addition we can have several external providers of maintenance services and this can lead to a sort of confusion in maintenance actions. In this paper we suggest an approach to achieve a condition based maintenance in old plants, without peculiar exceptions for the technology involved, maintained through a collaborative network of enterprises. A little plant prototype was built as a test case for the functioning of the expert system to manage the condition based maintenance and the network of skills involved.

Accelerated life tests for new product qualification: a case study in the household appliance

The increasing competition of global markets requires companies to focus their attentions on two main aspects of a production system: cost reduction and product quality. Product reliability performance is strongly correlated with the customer satisfaction and with its perception of the goods quality; in fact, product failures can represent one of the most serious damages for the manufacturer image. Reliability estimation through testing activities should be carried on in accordance with a timec the use of such testing method is useful to systematically support the design phase and to help the service forecasting before the product launch. The methodology has been tested on a case study regarding a new model of washing machine for domestic use. The application of accelerated life tests was able to stress one of the most important failure mode of the product, returning important validation data for the design phase.

A rule based expert system for maintenance as a competitive advantage

In the present work we describe the development of a condition based maintenance platform especially shaped for a network of maintenance companies operating on the same assets. The expert system developed in this study, holds the skills of a team of experts who thoroughly know both the monitored system and its maintenance. The company and the network of expertise available were also considered. Indeed, being a set of theoretical reference models already known in literature, we have developed a system which can support a network of actors, in order to increase the reliability of critical complex systems. Similar systems, specially shaped, could be very useful to reduce the downtimes and hence would be able to enhance the productivity of many Small and Medium Enterprises (SMEs). These may deem interesting the new market of networks of expertise, without being forced to resort to external companies just when they are unable to cope with maintenance problems with their own forces.