Advanced Materials Research Vols. 126-128

Abstract: The main body of grinding knowledge comes from the experiments done by independent investigators. If such experimental results are not made both human- and machine-comprehensible from the very beginning, then it would be difficult to reuse the results using a computerized network or any other means. In this respect, intelligent systems are needed to create human- and machine-comprehensible models of important results like 3D surface finish, cutting force, tool wear, etc. From this perspective, this paper describes a method for modeling and simulation of 3D surface finish of grinding. A human-friendly simulation tool is developed to implement the method. The simulation result is compared with the real 3D surface finish and a close correlation is found. The presented model can be integrated with the collaborative machining networks for better utilization of grinding resources using computers (e.g., condition monitoring, process planning, automation) and even using humans (e.g., effective exchange of information among peers in the research community and in the industry).

Abstract: The development of robust condition monitoring system for a machine tool spindle is an important task because the spindle has a significant effect on the processing quality. This paper presents the architecture of data acquisition system for detecting spindle vibration in turning processes in order to develop an on-line condition monitoring system. In this work, a solar-powered wireless sensor system is installed inside the spindle and is used to monitor the machine tool processing state in real time, thereby improving the processing quality. Accelerometer sensors are employed to estimate tool wear; these sensors monitor the vibration of the spindle. The vibration monitoring data of the high-speed spindle is wirelessly transmitted to an external information device in real time. As an alternative to sensors that employ wired power transmission, a solar energy transmission system has been developed to provide the required electric power to the sensor system. The experimental results show that the proposed system successfully measures the vibration frequency of the rotational machine tool spindle.

Abstract: The purpose of this study is to develop an in-process of measurement technique of surface roughness using thermoelectric effect in cylindrical grinding. The electromotive force (EMF) generates depend on the surface roughness of workpiece and the variation of workpiece temperature when the sensor with thermocouple wires rubs on the workpiece surface in grinding process. In this paper, the in-process measurement technique of surface roughness in cylindrical plunge grinding is proposed, conceiving the cancellation of the EMF caused by the variation of workpiece temperature in the sensor output. Also a new type in-process sensor was developed for high accuracy to overcome the problem which was clarified in the cancellation method of the influence of workpiece temperature at a basic sensor.

Abstract: Surface measurement using three-dimensional stylus instruments is a relatively new technique that offers numerous advantages over more traditional profilometry methods. The information generated is, unlike profile measurement, less subjective and more statistical providing additional insight into the surface structure. One application of surface measurement that has encountered problems when using the profilometry method is that of grinding wheel characterisation. The wheel surface texture (topography) and the conditions under which it is generated have a profound effect upon the grinding performance as characterised by the grinding forces, power consumption, temperature, and surface integrity of components. A detailed knowledge of the nature of the topography of the grinding wheel would provide further insight into surface interactions between the wheel and workpiece as well as enabling improved control of the grinding process in general. In this paper four diamond grinding wheels of 91 and 181 micron grit size were subjected to differing dressing conditions to produce varying final wheel topographies. Three-dimensional surface measurement techniques were employed to quantitatively characterise the topographic change and provide an aerial estimation of the number of cutting grains. The results demonstrate that the techniques can distinguish between a worn and dressed wheel. In addition, the parametric values generated from the various surfaces can aid the user in determining when re-dressing is required.

Abstract: The roundness error is researched in the process of coordinate polishing crankshaft crankpin with abrasive belt by measuring online. A detailed study on the tracing motion equations of the measurement system is made，so the mathematical model is obtained in this paper. In order to improve the in-situ measurement precision, the two-sensor tracing roundness error separation principle is proposed under motion stage. Finally, the conclusion that the source of errors could be determined initially according to online measurement of roundness errors is obtained, and then improving the accuracy by changing processing conditions timely.

Abstract: Pattern size controllability of SPM-based nano-lithography especially in vertical direction was improved using in-situ height and depth measurements at the processed point. The transient oxide growth was monitored by light transmission (depth of the oxide in sample metal surface) and topographical signals measurements obtained from a scanning near-field optical microscope. First, we investigated oxidizing rate limitation on titanium film. At the voltage rise faster than 10 V/sec, the depth growth didn’t follow the voltage change in spite of immediate upheaval growth. This result suggested the rate determining of reactive chemicals transport in the titanium oxide. Next, we discovered improvement in the process stability on intractable materials (e.g. iron group elements or noble metals; manganese in this paper) by using thin cap layer of titanium. As the result, the oxidization reaction progressed moderately due to the facts that the oxide of the cap layer is electrical insulative and restriction of the permeability of the reactive chemicals (ingredients of the oxide) that were electrochemically generated at apex of the probe tip.

Abstract: A Novel Piezoelectric Grinding Dynamometer for Monitoring Ultra-precision Grinding of Silicon Wafers

Abstract: Recently, the screens of TVs and computers are getting larger and larger. In accordance to that, surface plates of those, which are used during the production process, are also becoming bigger. These surface plates are required to be checked every certain period of duration. Therefore, an automatic measurement of straightness, that is highly accurate, and capable of measuring large area, is necessary. The straightness is the degree of difference from a straight line geometrically. It is one of the indexes to express machining precision. In Mechanical Engineering, the accuracy of processing side and the exactitude of the table and the surface plate, which are the bases of the processing side, decide the quality of products. There are a number of methods to measure the straightness. In this experiment, we use a straightness-measuring instrument, which moves a gauge parallel to the surface, and measure the values. Fig. 1 shows the appearance of straightness- measuring instrument. This straightness-measuring instrument is consisted of guide rail, carriage, and support blocks. During the actual measurement, the control of the carriage to connect the gauge is manually operated. This manual operation is simple, but measurement time and precision greatly depend on individual skill. In addition, measuring process requires good length of time with intensity, hence it causes the worker mental exhaustion. Therefore, if we can mechanically operate the carriage it will improve the accuracy and data collection will be easier. This research is aimed to mechanically operate the straightness-measuring instrument and measure consecutive positions in a short period of time. This report explains the design, production, and motion test of the automatic movement mechanism of the carriage.

Abstract: The Acoustic Emission signal was studied in this report for tool wear monitoring in micro milling. An experiment was conducted first to collect the AE signal generated from the workpiece during cutting process for characteristic analysis, training the system model and finally testing the system performance. In the system development, Acoustic Emission (AE) signals were first transformed to the frequency domain with different feature bandwidth, and then the Learning Vector Quantization (LVQ) algorithms was adopted for classifying the tool wear condition based on the generated AE spectral features. The results show that the frequency domain signal provides the better characteristics for monitoring tool wear condition than the time domain signal. In considering the capability of the AE signal combined with LVQ algorithms, the sharp tool condition can be detected successfully. At the same time, 80% to 95% of the classification rate can be obtained in this study for the worn tool test. Moreover, the increase of the feature bandwidth improved the classification rate for the worn tool case and 95% of classification rate for the case with 10 kHz feature bandwidth.

Abstract: We present a new type of wafer probe card with resin film consisting of two beams. Resin film is embedded on both sides of the probe beam, having a thickness of 4 [μm] and made from polyimide. This proposed probe enables compliant structures with large overdrive to ensure high durability of the structure and controllable scrub motion to assure cleaning process. In this study, Matrix method is introduced for theoretical studies of the probe structure and commercial finite element code is used. Electrical contact resistance is determined by theoretical studies based on Holm's theory and experimentally by　our measurement instrumentation respectively. The structure is proven theoretically to get appropriate scrub motion when it undergoes a large overdrive with preferable exhibited contact force. Moreover, all of these mechanical characteristics can be varied to know the values of the character of probes. The methodology having one of the most preferable characters of the contact-probe had been achieved.