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Page 475 of 977 Results 4741 - 4750 of 9762

Andreas Loderer, Bogdan Galovskyi, Wito Hartmann, Tino Hausotte
QUALIFYING MEASURING SYSTEMS BY USING SIX SIGMA

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.

Koichi Kurita
HUMAN PHYSICAL ACTIVITY MEASUREMENT METHOD BASED ON ELECTROSTATIC INDUCTION

In this study, an effective noncontact technique for the detection of human physical activity is proposed. We have develop a method for measuring human physical activity, which is based on detecting the electrostatic induction current generated by the walking motion under non-contact and non-attached conditions. A theoretical model for the electrostatic induction current generated because of a change in the electric potential of the human body is alsoproposed. By comparing the obtained electrostatic induction current with the theoretical model, it becomes obvious that this model effectively explains the behavior of the waveform of the electrostatic induction current. The normal walking motions of daily living are recorded using a portable sensor measurement located in an ordinary house. The obtained results show that detailed information regarding physical activity such as a walking cycle can be estimated using our proposed technique. This suggests that the proposed technique, which is based on the detection of the walking signal, can be successfully applied to the estimation of human physical activity.

Piotr Grudowski, Malgorzata Wisniewska, Ewa Zajkowska-Leseure
NEEDS AND PROBLEMS OF SMES IN THE CONTEXT OF LEAN SIX SIGMA METHODOLOGY. FRENCH AND POLISH PERSPECTIVE

The article presents the results of the research conducted in Polish and French SMEs 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 experience 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.

Jacek Gogól
THERMAL ISSUES IN MACHINE TOOLS AND COORDINATE MEASURING MACHINE SIMILARITIES AND DIFFERENCES.

Thermal issues are relatively well developed and described in machine tools and their development is quite rapid in recent decades. This is related to increased awareness of the impact of thermal conditions on the accuracy and efficiency of their work and the increased requirements of users (up to 75% of the overall geometrical errors of machined workpieces can be induced by the effects of temperatures). There is a large stock of published research and case studies aimed at compensation and reduction of thermal error of machine tools.
Branch of coordinate measuring machine (CMM) is strongly associated with the machine tool industry. There are a lot of convergence in approach to this theme in both subject groups. Both in the construction of machine tools and measuring machines as the key point of interest is the influence of various physical phenomena on the behavior of the executive point, in the case of measuring machines is the end of the measuring head, in the case of machine tools is a tool centre point (TCP). Considerable amount of research on the effects of thermal phenomena in the case of machine tools is carried out without taking into account the cutting forces, which also conforms research approach in both concerned areas. An important difference, however, is the fact that the compensation of thermal deformation in machine tools must be made immediately during work, if we want to improve the geometric parameters of the workpiece, which involves the introduction of some actuators, or correction of the trajectory in real time. While the result of work of the measurement machine are stored data that can be corrected or processed after the process of measuring and correction does not make any material actuator. Order of magnitude of precision in the case of machine tools and CMM is also different.
Thermal phenomena associated with measuring machines are relatively well developed in the case of steady thermal state, and the uniform temperature gradient. Mathematical models are described, compensation systems have been developed. There are imeko_proceedings concerned with selected aspects of the measuring machine work, or selected components that generate heat inside or outside of the machine structure. However problem of modeling of the whole machine and studies of thermal effects, and timevarying or locally occurring phenomenon ,based on numerical methods is relatively poorly studied. This probably results from the fact that both numerical methods and hardware have developed enough to address this issue only in recent decades. Important here is the economic aspect (the cost of computing hardware and software), and the performance parameters, which allow the calculation of the real-time close to the real-time or made in acceptable period of time post factum.

Jan Rewilak
MSA PLANNING - A PROPOSITION OF A METHOD

Measurement System Analysis (MSA) is a mandatory element of quality management systems in automotive industry. Suppliers has to comply both with ISO/TS 16949 and meet customer requirements specified in APQP (Advanced Product Quality Planning), PPAP (Production Part Approval Process) and MSA manuals.
Manufacturing companies (not only in automotive industry) perform MSA studies for all measuring instruments specified in Control Plans. There are variety of methods available, with gauge R&R as the most popular, to conduct assessment of capability of a measuring system. However, although the assessment has to be performed periodically, none of the above mentioned standards and manuals suggest any method for MSA planning. The paper describes a few propositions on how the problem can be 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 orachieved) and characteristics impact on product/process function for making a decision on MSA frequency and scope.
The second method assumes that a process FMEA (Failure Mode and Effects Analysis) is developed. The methoduses performed FMEA to establish priorities for MSA. Basing on the priorities, frequency and scope of MSA can be planned.

Chu-shik Kang, Jong-ahn Kim, Jonghan Jin, Tae Bong Eom, Ho Suhng Suh, Jae Wan Kim
A SIMPLE OPTICAL SENSOR FOR THE STRAIGHTNESS ERROR MEASUREMENT OF A MOVING STAGE

The watt balance, a metrological instrument that might provide the new definition of the kilogram, consists of a moving coil which has a tight tolerance for its straight motion. Normal straightness sensors cannot be used for the watt balance because any electronic device might disturb the magnetic field around the coil. We propose a simple optical sensor to measure out-of-straightness of a moving coil. The sensor is comprised of a cube-corner prism and a reflector having a sharp edge. When a laser beam is incident on the cube-corner prism which is located on the moving coil, any out-of-straightness movement of the coil shifts the outcoming beam. The shifted beam is partly reflected by the edge reflector and the rest of the beam transmitted. Each beam is collected into an optical fiber and sent to a balanced photo detector. The lock-in detection is used for measuring the difference of the reflected beam intensities. After obtaining the relation between the amount of beam-shift and the lock-in output signal by using the knife edge scanning method, the straightness error of a moving stage could be measured with high accuracy. In our preliminary experiment which was performed in air, the sensitivity of the sensor was 2.457 mV/nm, and the nonlinearity of the sensor turned out to be about 0.7 % for the straightness error range of ±7 mm.

Krzysztof Nadolny, Wojciech Kaplonek, Pawel Sutowski
COMBINED OF THE CLSM-SEM TECHNIQUES FOR MEASUREMENT AND ANALYSIS OF THE SINGLE GRAIN CUTTING SCRATCH ON INCOLOY® ALLOY 800HT®

Knowledge and understanding of modern machining processes often requires the use of advanced microscopy techniques, such as, among others confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). This work focused on the application of these microscopic techniques for measuring and analyzing of traces made by single abrasive grain cut, formed on the internal cylindrical surface of the sample made of INCOLOY® alloy 800HT®. The work was divided into two parts. In the first one, the most important types of materials machinability and grindability tests were briefly characterized, with particular reference to issues related with the testing of hard-to-cut materials. The most important properties of the sample as well as the methodology and equipment used in the experimental tests were also described. The second part contains a description of used microscopic techniques and presents selected results of measurements and analyses carried out on the trace shaped by single abrasive grain of microcrystalline sintered corundum SG™. All results presented in this part were obtained using a 3D laser microscope LEXT OLS4000 by Olympus and electron microscope JSM-5500LV by JEOL with dispersive spectrometer module INCAPentaFET-x3 with Si(Li) detector by Oxford Instruments. The results were compared with reference measurements obtained using a opto-digital microscope DSX500 by Olympus.

Wojciech Kaplonek, Czeslaw Lukianowicz
NON-CONTACT OPTICAL METROLOGY FOR AUTOMATED IN-PROCESS INSPECTION OF MACHINED SURFACES

This work presents a concise review of selected issues related to non-contact optical metrology in applications where automated in-process inspection is involved. A brief description of the in-process inspection and applicable procedures were presented. A laser method based on analysis of scattered light was elaboratedin greater detail. In addition to the above, a short review of selected technical solutions in a form of an experimental and commercially manufactured measurement systems was presented. This review concentrates on describing of the most important metrological parameters, principles of operation and areas of applications of the aforementioned measurement systems. In the final part of the work a subjective selection of literature references was listed.

Marzena Miesikowska, Evert De Ruiter, Leszek Radziszewski, Stanislaw Bien, Slawomir Okla
ACOUSTICS IN ROOMS FOR REHABILITATION OF LARYNGECTOMEES

Laryngectomy is a medical operation, resulting in the loss of “normal” speech. Laryngectomees can learn to speak using their oesophagus; this takes intensive training, often in groups of about 5-10 patients and a trainer. It has become clear that in hospitals the requirements for rooms,meant for this type of rehabilitation are often not met.
The aim of this research is to improve the acoustic functionality of the rooms for rehabilitation of laryngectomees. To this end, the acoustic parameters of such rooms have been measured: reverberation times, background levels, sound insulation of surrounding partitions.
Comparison with the requirements from earlier empirical knowledge shows the elements that have to be improved. The proposed measures include addition of sound absorbing finishing in specific positions, and better sound insulating doors.

Andreas Gröschl, Gökhan Akkasoglu, Andreas Loderer, Wojciech Plowucha, Teresa Werner, Paul Bills, Tino Hausotte
MUVOT - ESTABLISHING AN INTERNATIONAL VOCATIONAL TRAINING PROGRAM ON THE TOPIC OF MEASUREMENT UNCERTAINTY

Measurement results represent important information, which are necessary for evaluating and improving the quality of manufactured products and to control manufacturing processes. Furthermore, they build the basis for numerous decisions in the field of quality management, process and production automation or product development and design.
Knowledge about the acquisition, evaluation and interpretation of measurement data as well as an understanding of the relevant influences on those measurement results are essential for employees working in the field of manufacturing metrology. Measurement results are always afflicted with deviations, due to a variety of causes. It follows that in order to assign a value to the reliability and quality of a measurement result its uncertainty must be determined and considered. However, employees in the field of quality management or metrology are often not familiar with methods for determination and interpretation of measurement uncertainty, because appropriate opportunities for training are missing in current vocational education.
This need has led to the creation of the European project MUVoT, which will create a course for advanced vocational training in determining measurement uncertainty. The training course is based on a blended learning concept, combining self-dependent learning via a web-based platform and face-to-face workshops. This allows the adaption of individual knowledge and skills by self-controlled learning of abstract contents whilst the exercises enable the practical application of typical methods, which are generally considered as quite complex by many employees, and thus assure correct understanding. The featured Blended Learning concept facilitates the integration of the training into a workplace setting, thus the idea of Lifelong Learning is promoted in new fields of application. The curriculum and training concept for this newly developed training program have been designed such that the course can be applied internationally. To facilitate this, a harmonized scheme for course structure and contents has been defined albeit with inherent flexibility, allowing the adaptation to specific constraints.

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