Key Engineering Materials Vol. 637

Abstract: The article presents results of the research conducted in Polish and French small and medium-sized enterprises referring to the context of the implementation and application of the concept of Lean Six Sigma. The research was conducted in the form of case studies, observations and individual interviews. The pilot studies led to the identification of the needs, expectations, concerns and experiences of these companies. At the same time possible benefits and the barriers related to the implementation of the Lean Six Sigma methodology in the SMEs were disclosed. The results of the research considered also the suggestions and expectations of the employees of the surveyed organizations. The majority of companies using elements of the LSS in both countries had difficulty with the correct use of the of Lean or Six Sigma tools. These results ultimately confirmed the demand for Lean Six Sigma methodology dedicated to SME sector.

Abstract: The paper presents new procedure of methodology for statistical assessment of measurement systems variation (methodology known in the literature as Measurement Systems Analysis, MSA). This procedure allows for calculation and monitoring in real time (that is on-line) of measurement system (MS) characteristics which determine its usability for manufacturing process control. The presented solution pointed out the gap in process control, which consists in lack of methods for monitoring measurement processes in the on-line way. Their key point consists of taking samples that are also needed for the process control chart for the needs of the MSA method. This means that the samples are taken directly from the production line and during the production process. The method is combined with the standard procedure of statistical process control (SPC) with the use of process control charts. It is based on two control charts. The first one is called AD-chart (Average Difference chart) and it allows to estimate the variation between the operators and stability of the monitored measurement system. The second control chart illustrates the %R&R index (Repeatability and Reproducibility) and allows to monitor the MS capability.The paper also presents authors’ proposal of guidelines about the reference value for the %R&R index calculation and assessment. Recommendations and guidelines for choosing the reference value are based on two criteria: information about sample and manufacturing process variation and the purpose of using MS (product or process control).

Abstract: This paper presents the elements of metrology laboratory accreditation for calibration in the scope of calibration E-05 Dimensions, and calibration for the subject: the distance and angle measures. During the accreditation, but also in its maintenance, calibration laboratories must prove their competence. Each laboratory must have the quality management procedures for monitoring the validity of the calibrations performed. This monitoring shall be planned and reviewed through: internal quality control, participation in the interlaboratory comparisons or proficiency testing schemes, repeated calibrations using the same or different methods, re-calibration of the saved samples and correlation of results for different characteristics of the sample. According to the ISO/IEC 17025:2005 standard, competence is proved by participating in interlaboratory comparisons or participation in Proficiency testing (PT) schemes. This paper aims to stimulate discussion and debate about ways of proving competence of calibration laboratories. We believe that, in the interpretation of ISO/IEC 17025, the laboratory can demonstrate competence by participating in any activity, PT schemes or interlaboratory comparisons, and they are equal to this need. The procedure and the results of the interlaboratory comparisons between two accredited laboratories will be described.

Abstract: Classic intention, which pursues the management of any company – is to improve the quality and competitiveness of its own production, aiming at the end to speed up the receiving of profit. Such an implementation is primarily made possible by optimizing production processes. The manufacturing processes are influenced by various factors that may lead to deviations from the process requirements. Management of processes is needed to counteract such change in the process.Processes that are not managed, can lead to the production of a large number of defective products earlier before the detection of nonconformity, causing significant damage and lead to disruption of production schedules. It is important to develop an effective system of management and control, capable of detecting variations in the process as early as possible so you can take corrective action before it is produced by a large number of defective products. To optimize production processes in quality assurance the following systems have been known as Theory of Constraints, Lean, Six Sigma. Typically, these systems are used separately. However, their combination and comprehensive utilization can be more efficient and can give a much better result.As a rule, first by using Theory of Constraints (TOC) the bottleneck is defined – weak area, which is an obstacle of improving of the quality and efficiency of the company and profit increasing. Then Lean tools manage this area. And the next phase includes Six Sigma, which allows you to receive a significant increase in the effectiveness and efficiency of production and profit.Each of these techniques is unique and their complex usage is important in managing the quality of processes and products.

Abstract: Nowadays there is a strong relationship between the quality control and quality engineering in the modern advanced manufacturing. Quality engineering is an interdisciplinary science which is concerned with not only producing satisfactory products for customers but also reducing the total loss. Quality engineering involves engineering design, process operations, after-sales services, economics and statistics. Although the Taguchi Robust Design is the first concept comes to mind when thinking of quality engineering, the definition of this major has been used in different manners in the literature. There are also differences on the definition of the quality which has been made by experts. The aim of this study is to contribute to the literature to avoid deviations on definition of the concept of "Quality Engineering", which has not been defined yet by ISO - International Organization for Standardization. This study pointed out that the process of quality control is a part of on-line quality engineering rather than off-line phase and tries to ensure planned and/or improved values are satisfied during mass production.

Abstract: The technology of sheet-bulk metal forming enables the production of complex workpieces with filigree surface structures in only a few forming steps. In order to provide a rapid and production-related workpiece inspection of not only large workpiece features, but also small features in an appropriate quality, a multi-sensor optical measurement system with different resolutions is required. Workpiece features of medium size can be measured by two types of fringe projection sensors. With a structured approach according to Six Sigma, which is based on the five phases design, measure, analyze, improve and control complex tasks are divided into smaller individual problems. In each phase the Six Sigma method recommends tools for solving the individual problems effectively. With the support of the Six Sigma guideline an exemplary sheet-bulk metal forming workpiece feature is used in order to qualify the two measuring systems for a production-related measurement. After defining the explicit goal for the investigations, a detailed analysis of the measurement process leads to a couple of relevant influences. These are input factors for the design of experiments. By a full factorial design, not only an influence of a factor itself, also the interactions between multiple factors can be detected. In the analyze-phase, these results are calculated by different statistical methods. To present the results in a comprehensible way several types of diagrams are used. The shown approach gives an example for a traceable and methodical way to qualify a measurement system for challenging measurement tasks.

Abstract: Measurement System Analysis (MSA) comprises a set of methods aiming to identify and assess variation of measurement results that can be assigned to a measurement system (gauge, personnel, procedure, standard, ambient conditions, etc.). It became a requirement of quality management systems in automotive industry, according to ISO/TS 16949. Moreover, most of automotive suppliers have to meet OEMs requirements specified in APQP (Advanced Product Quality Planning), PPAP (Production Part Approval Process) and MSA manuals. Many other industries adopted the same approach, expecting their suppliers to perform MSA in compliance with the above guidelines. The basic requirement regarding MSA scope is that it should be carried out for all measuring instruments referred to in Control Plans. Among methods available, gauge R&R seems to be the most popular method of measuring system capability assessment. However, although the assessment has to be performed periodically, none of the above mentioned guidelines suggest any method for MSA planning. The paper describes a few propositions on how the problem can be practically resolved basing on a risk associated with each measurement system. The first proposed method is based on simple risk analysis, which can be easily run together with developing a Control Plan. It uses process capability index (required or achieved) and characteristics impact on product/process function for making a decision on MSA frequency and scope. The variant of the method uses gauge robustness assessment as another risk factor.The other proposition assumes that a process FMEA (Failure Mode and Effects Analysis) is developed. The method uses performed FMEA to establish priorities for MSA. Basing on the priorities, frequency and scope of MSA can be planned.

Abstract: The measurements were performed on the surfaces made of different materials and typical of diversified character. Glass roughness standards with sinusoidal profile, approximately sinusoidal profile and metallic comparative standards after lathing and grinding were object of research. Analysis was performed including the surface and profile evaluation. Statistical analysis was conducted. Measurement sections and other filter parameters were selected in accordance with standards. Measurements were carried out with stylus tip contact method – using TOPO 01P device designed by The Institute of Advanced Manufacturing Technology, that uses diamond tip inductive sensor. Tip sensor radius is equal to 2 μm. The results of measurements were filtered by: Gaussian filter, Robust Gaussian regression Filter, Spline, Spline Wavelet, Morphological Filter. Gaussian Filter uses linear system based on Fourier wavelengths. Robust Gauss Regression Filter is similar to Gaussian Filter, but it is insensitive on the specified phenomena in input signal. Spline Filter is based on linear polynomial combination. Wavelet Filter decomposes profile on constant shape elements, but on different scales. Morphological Filter operates on the principle of filtered profile plotting using circular disc or horizontal line segment with a specified (respectively) radius or length. Selection of suitable filtration method is essential and one of the most important things to obtain reliable measurement results evaluation. Not all filters are suitable for each type of surface. Filter algorithms differ from each other and this influences in a greater or lesser degree on the roughness profile and hence on roughness parameters and waviness parameters related to it.

Abstract: Surface roughness is a factor that has a vital influence on overall quality of machine parts. This is the reason why proper measurements of surface roughness are a matter of great importance in modern manufacturing technology. Nowadays portable profilometers are common instruments to be used under industrial conditions. Measurements with such instruments can be affected by numerous factors, for example environmental changes, human errors of an operator, etc. This paper discusses problem of an evaluation of measurement accuracy of portable profilometers. It also describes the evaluation procedure and presents results experimental tests.