António Ramos Pires

Guidelines to help practitioners of design of experiments

Purpose – The purpose of this paper is to focus the application of design of experiments (DOE) using industrial equipments, reinforcing idea that non‐statistical aspects in planning and conducting experiments are so important as formal design and analysis.Design/methodology/approach – Two case studies are presented to illustrate typical industrial applications and difficulties. Supported on these case studies and literature, this paper presents guidelines to planning, conducting and analysis involving technical and organizational aspects.Findings – Solving problems in industry, including in companies recognized as competent in the respective industrial sector, is not just a question of applying the right technique. Ceramic industry case study illustrates how important are non‐statistical issues in DOE application. Paint industry case study illustrates the strong relationship of the results with incorporating presented guidelines into practice. Moreover, both case studies consolidating a fundamental advant...

Management of quality-related costs: the case of Portuguese companies

The traditional view of quality-related costs (QRC) tries to justify investment in prevention as a way to reduce the costs of failure. But this static view must counter a more dynamic vision that fosters continuous improvement and assesses the costs and benefits of implementing techniques and methods of quality management, such as certification of ISO 9001systems. However, it is unknown whether such companies are also engaged in the management of QRC arising from activities undertaken, either at the level of monitoring, or coming from failures, and if such organisations verify (or not) the recovery of investments in quality. In this sense, the present article aims to provide insight into the procedures adopted by Portuguese companies in managing QRC, and to assess the extent to which management reports allow the analysis of quality costs and contribute to the related planning and control activities. The results of this study showed that there is hardly any assent to the implementation of formal mechanisms for planning and control of QRC, and to the explicit identification and segregation of those costs in management reports.

Analysis of multi-axis milling in an anthropomorphic robot, using the design of experiments methodology

Abstract Currently, the concept of advanced machining technologies (AMT) includes different processes such as high-speed machining, multi-axis machining, etc. The common characteristic between these technologies is that they aim to improve the cutting process. Research done in the past has mainly concentrated on metal machining. In this present research, efforts are made to apply these techniques to the ceramic industry. This work forms part of the ongoing research at Staffordshire University into the application of CNC machining techniques in the production of models and moulds, with regards to the production of tableware and sanitaryware items. This paper focuses on the analysis of multi-axis milling using an anthropomorphic robot to produce near net shape plaster parts. The robotic system was run based on a specific set-up that allows multi-axes toolpaths and avoids “Gimbal Lock” singularity. The milling tests were carried out on plaster using conventional cutting tools (slot-mills). The design of experiments (DoE) was implemented using factorial techniques. The surface quality and geometric accuracy of the plaster parts were the response variables used to characterise the part quality and test the levels of acceptability of lead/lag angle, feed-rate and robot arm-extension. A mathematical equation based on the geometric accuracy was developed and used to plot flatness contours. Through these plots it is easy to define other possible combinations of feed-rate and robot arm-extension that can be used.

Dependency relationships between critical factors of quality and employee satisfaction

The literature has paid very little attention to the effects of the critical factors of quality on employee satisfaction in the tourism context. Therefore, the aim of this study is to examine these relationships among tourist accommodation enterprises considering the perception of quality managers. A theoretical model together with the hypotheses to be contrasted is proposed and it is validated by the technique of structural equation models. The target population of the study is made up of tourist accommodations certified with ‘Q for Quality’ in Spain. The structural equation model provides evidence that the critical factor antecedents of employee satisfaction are process management and quality policy and planning; the latter criterion has a greater influence. The study also found that leadership is an important factor for obtaining results from employees through the rest of the variables that make up the model and employee satisfaction promotes learning within the organisation.

How companies use the information about quality-related costs

This work focuses on the broad topic of quality-related costs (QRC), which has been largely discussed in the literature. Nevertheless, one of the least studied issues relates to the way companies use QRC information. In this research the profile of use of QRC information is analysed considering the model proposed by Simons [(1991). Strategic orientation and top management attention to control systems. Strategic Management Journal, 12(1), 49–62], from which it is possible to distinguish between a diagnostic and an interactive profile of use. The analysis of the data collected through a questionnaire survey to a sample of Portuguese certified companies (PCCs) involved the application of principal component analysis, cluster analysis, one-way analysis of variance and discriminant analysis. The results showed that a substantial part of PCCs use the QRC information according to a diagnostic and interactive profile. Managers of these companies use QRC information to set goals, monitor their implementation and motivate participants (according to a diagnostic profile), but also to foster organisational learning, the emergence of new ideas and strategies (according to an interactive profile). About 30% of companies favour a diagnostic profile. However, about 32% of companies report negative values for both profiles, indicating that these companies undertake initiatives to prepare QRC information but their leaders do not use it in the management process.

Development of a tool life prediction model for plaster machining

This paper reviews the developments of the ongoing research at the Staffordshire University into the application of Computer Numerical Control (CNC) machining techniques to produce plaster moulds and prototypes. The experimental work was carried out on plaster using conventional cutting tools (slot-mills), using a six-axis anthropomorphic robot. Based on the tool wear (Flank Wear ? VB) measurements, an analysis of the cutting tool failure was undertaken. This work had comprised of three phases. Initially, an experimental screening was carried out in order to identify the major important criteria regarding the cutting tool wear problem. The second phase corresponded to the development of a tool life prediction model for the machining of the plaster material. The calculations were carried out using the response surface methodology and the 23 factorial design. The experimental results showed that the cutting speed is the most significant factor to the tool wear process. Finally, results developed from a theoretical analysis with the tool life prediction model were compared with the experimental results. This test demonstrates the validity of the theoretical analysis and showed how the optimisation process can be performed using this methodology.

Tool Wear Analysis Using Factorial Techniques

This paper reviews the developments of the ongoing research into the application of CNC machining techniques to produce plaster moulds and prototypes. The experimental work was carried out on an anthropomorphic robot that produces the near net shape plaster parts. The milling tests were carried out on plaster using conventional cutting tools (slot-mills). The tool failure analysis was based on the tool wear (Flank wear VB) measurement. This work had comprised three phases. Initially, an experimental screening was carried out in order to identify the major important criteria regarding the cutting tool wear problem. The second phase corresponded to the development of a tool life prediction model for the machining of the plaster material. The calculations were carried out using the response surface methodology and the 2 factorial design. The experimental results showed that the cutting speed is the most significant factor to the tool wear process. Finally, results developed from a theoretical analysis with the tool life prediction model were compared with the experimental results. This test demonstrates the validity of the theoretical analysis and showed how the optimisation process can be performed using this methodology.