Carla Schwengber ten Caten

MINIMIZING MANUFACTURING AND QUALITY COSTS IN MULTIRESPONSE OPTIMIZATION

Determination of the best operational settings for products or processes is usually accomplished through single-objective-function optimization routines, but in order to select the best design and operating control factors, all measures of quality must ..

Lean schools of thought

Academia has produced theoretical and practical knowledge about lean for over 30 years, and for that reason, research is in a mature phase. To organise this knowledge, we propose a typology of lean schools of thought. Schools were categorised into two paradigms of organisational analysis – interpretivist and functionalist – to clarify theoretical assumptions about how each conducts scientific investigations and what contributions they generate. Seven schools were identified: systems engineering, systems architecture, operations research, organisational development, contingency systems, socio-technical systems and evolutionary. Persistent practical problems should guide production and operations management research such as the difficulties companies face with adoption and sustainability of lean practices. The typology proposed in this study provides a theoretical framework and a respective school for these problematical situations. The evolutionary school in the interpretivist paradigm seems to be more appropriate; action research as a methodology should be used since it is consistent with interpretivism assumptions. The originality of this paper lies within a proposal of lean schools of thought not found in the literature. Directions for research that have more meaning for companies seeking lean transformation are proposed.

Integrated process control

Presents a new procedure for quality control and quality assurance in scenarios where several variables and attributes have to be monitored. The proposed procedure, named integrated process control, begins with the definition of control stations on the production line, where a single chart that aggregates several variables and attributes is used. This procedure is complemented by using Pareto charts, which determine the quality characteristics contributing the most to the number of defectives. The integrated process control also uses traditional control charts; however, these are used selectively following the indication of the Pareto charts. The joint use of these tools facilitates the identification and solution of quality problems, allowing the improvement actions to be taken at the right time and place. The key advantages of the proposed procedure are: the ability to handle variables and attributes on a single integrated chart, the statistical approach, providing a solid basis for decision making, and the strong managerial appeal provided by the integrated charts.

Proficiency tests for laboratories: a systematic review

Abstract Laboratories analytical results must be reliable. Proficiency tests (PT) main objective is to provide independent demonstrations of laboratory competence. The demand for these activities is increasing on the world scenario, as well as its importance. The main objective of this study is to identify the important publications of the PT theme from 2005 to 2012 based on a systematic review procedure. The method proposed reached a total of 113 papers published in indexed journals and another 34 additional references, including standards, guidelines and recommendations of international or regional accreditation body cooperation, international standards organization and international metrological institutes. All selected references were clustered based on its approach, and then the main practices were presented. The approaches identified were related to performance assessment, calculation method for performance assessment, use of PT for validation and/or estimation of measurement uncertainty and management of PT. Results indicate some opportunities to develop researches, such as: project management related to PT, the importance of analyses of data probability distribution function when consensus value is used, criteria to select the parameter to homogeneity and stability tests and to explore the link between PT, method validation and measurement uncertainty, among others.

A process approach to ISO/IEC 17025 in the implementation of a quality management system in testing laboratories

The introduction of quality management systems (QMS) and the accreditation of laboratories according to ISO/IEC 17025 standard are not easy tasks, mainly for those laboratories located at teaching and research institutions. During the implementation of QMS at two testing laboratories of the Federal University of Rio Grande do Sul in Brazil, new solutions to overcome some of the difficulties inherent to this type of environment have been found. The knowledge acquired through this work has led to the proposition of some general steps incorporating a process approach presented in this article, which could be of use to laboratories in their pursuit for accreditation. This proposal suggests the use of strategic planning information, links the QMS objectives to the corresponding processes and sets a few indicators to monitor both performance of and improvements to the system.

RFID‐Env: methods and software simulation for RFID environments

Purpose – The purpose of this paper is to present the results of an analytical and experimental research for the development of an innovative product designated RFID environment (RFID‐Env). This software is designed for the use of professionals in computer systems and plant engineering who are engaged in research and development (R&D) of ultra high frequency (UHF) passive radio frequency identification (RFID) systems as applied to the management and operation of logistic supply chains.Design/methodology/approach – The RFID‐Env makes it possible to simulate on computer screens a complete RFID‐Env by processing user data on the technical and physical characteristics of real or virtual RFID‐Envs. Information outputted can include descriptions of the performance to be expected from a given configuration and detailed reports as to whether that particular configuration will succeed in reading all the RFID tags flowing through a defined system.Findings – The paper shows the models and methods on how these simula...

18 comparative aspects between Lean and Six Sigma

Purpose – This paper aims to presents a conceptual comparative analysis of Lean manufacturing and Six Sigma, highlighting 18 critical aspects between such approaches and their respective implications for management decision-making. Design/methodology/approach – Qualitative approach based on the results obtained from literature review about Lean and Six Sigma. Findings – The main points of divergence between Lean and Six Sigma have been highlighted based on 18 criteria. Seventeen criteria are proposed as a result of a review of the literature and one criterion, and “quality control”, is suggested by the authors. Research limitations/implications – This article mitigates the literature gap regarding whether and how Lean and Six Sigma are synergistic approaches. Practical implications – This study enables decision-makers to evaluate the Lean and Six Sigma practices. The results of the analysis performed originated three observations: first, both approaches are predominantly complementary; second, it is possi...

Assessment model for organizational business process maturity with a focus on BPM governance practices

Purpose – The purpose of this paper is to propose an assessment model for process management maturity focussed on business process management (BPM) governance practices. Design/methodology/approach – This investigation uses case studies. Findings – The BPM governance elements identified and analysis of the BPM maturity models previously used gave rise to the assessment model for organizational maturity in BPM developed for this study. Originality/value – The model allowed the authors to diagnose organizations’ current situation in terms of process management and provided a preliminary assessment of the next steps in the evolution of maturity for each of the factors analyzed.

Guidance Documents on Measurement Uncertainty: An Overview and Critical Analysis

Abstract: The “Guide to the Expression of Uncertainty in Measurement” (GUM) is considered to be the main reference guidance document about measurement uncertainty. Although the GUM was first published more than 10 years ago, this subject is still acknowledged as a topic of major concern in metrology and is now also being applied to the field of testing. In order to assist both testing and calibration laboratories in a better understanding and application of the GUMs principles, many derived guidance documents specific to the GUM have been created by several metrology organizations. Some of these documents are detailed guides with specific fields of application, such as the EURACHEM/CITAC Guide for analytical chemistry. Other documents are more general, like EA-4/16 which covers any quantitative test. Knowing the advantages and drawbacks of each document and deciding which one to use as a reference document can be a difficult task for any metrologist or test engineer. In this context, the aim of this paper is to present a brief summary of each of these guidance documents, as well as a critical analysis of their main pros and cons. The paper also presents a comparison of these documents with regard to their field of application, level of knowledge required by the metrologist, whether practical examples are presented, whether correlation effects are presented, etc. As a result, this paper clarifies the differences, advantages, and limitations of these frequently applied reference documents, thereby assisting laboratories in deciding which document to use as their reference for measurement uncertainty estimation.

Beta control charts for monitoring fraction data

p-Charts and np-Charts are commonly used in monitoring variables of the fraction type and these charts assume that the monitored variables are binomially distributed. In this paper we propose a new control chart called Beta Charts, for monitoring fraction data (p). The Beta Chart presents the control limits based on the Beta probability distribution. It was applied for monitoring the variables in three real studies, and it was compared to the control limits with three schemes. The comparative analysis showed that: (i) Beta approximation to the Binomial distribution was more appropriate with values confined in the [0,1]-interval; and (ii) the charts proposed were more sensitive to the average run length (ARL), in both in-control and out-of-control processes monitoring. The Beta Charts outperform the control charts analyzed for monitoring fraction data.