• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1997.10a
• /
• pp.254-259
• /
• 1997

The measurement of surface roughness and waviness by means of noncontact method is an important area to be developed for GAC(Geometrical Adaptive Control) system. This paper deal with the design of noncontact in-process measurement system which measures the surface roughness and waviness during cylindrical grinding. This measuring system is simple and the apparatus proposed is composed of a laser unit, photodetector and optical system. During operation, the surface of a workpiece is continuously scanned by a laser beam. This method makes it possible to detect the surface roughness and waviness along the feed direction by control the spot diameter of laser beam. The experimental results show that the presence of chattering, loading and glazing can be detected sensitively along the feed directions.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.1 s.94
• /
• pp.167-173
• /
• 1999

This paper presents results of monitoring grinding processes with on-the-machine measurement of surface roughness by using nux ratios of scattered lights. A compact, on-the-machine surface roughness sensor. which consists of a diodelaser and several optic units. is developed. The control unit is also developed. The developed sensor together with the controller is applied for monitoring grinding processes of two different grinding machines. Experimental results show that the nux ratios and their standard deviations measured by the developed sensor over the entire ground surface are useful for monitoring grinding conditions. In particular, the sensor and the control unit are proved to be useful for monitoring grinding processes in order to detect abnormal grinding conditions and dressing time.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.845-850
• /
• 2003

The scattered light pattern from a machined surface generally contains much information concerning the surface roughness. The light pattern can be acquired by optical system and analyzed by statistical method. This kind of surface roughness measurement system can be easily adopted on the machine measurement. But the fully assembled system is too complex to implement on small systems using micro-controller. This study proposes the idea of reducing the number of optical components by removing screen and examines image processing of a light pattern to minimize the negative result of incomplete optical system. And the Gaussian blur filtering is concluded to be the best method of proposed measurement system. Furthermore light intensity variation of image pattern can be treated as a signal, therefore FIR filtering gives the similar result of Gaussian blur effect.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.42-47
• /
• 2001

The heat (mass) transfer characteristics on the blade surface of a first-stage turbine rotor cascade for power generation has been investigated by employing the naphthalene sublimation technique. A four-axis profile measurement system is successfully developed for the measurements of the local heat (mass) transfer coefficient on the curved blade surface. The experiment is carried out at the free-stream Reynolds number and turbulence intensity of $2.09\times10^5$ and 1.2%. The results on the blade surfaces show that the local heat (mass) transfer on the suction surface is strongly influenced by the endwall vortices, but that on the pressure surface shows a nearly two-dimensional nature. The pressure surface has a more uniform distribution of heat load than the suction one.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.04a
• /
• pp.613-617
• /
• 2000

This paper descries the effect of the stylus tip size on the measuring error in surface topography measurement. To analyze the distortional effect of an actual surface geometry originating from the finite stylus size, the surface is modeled as a sinusoid and the stylus tip as a circle. the measuring error is defined as the ratio of the standard deviation of a tracing profile and an original profile. It is shown that this measuring error depends on the amplitude and wavelength of an original profile. In this paper, the spectrum analysis is applied to investigate the distortional effect due to the mechanical filtering of the stylus in the frequency domain. and, the cumulative power spectrum is applied to determinate the minimum wavelength limits to be measured with the various stylus tip radius from these results, a new method to select proper stylus tip radius is proposed.

• Journal of Surface Science and Engineering
• /
• v.29 no.6
• /
• pp.728-734
• /
• 1996

To obtain the relation in the electrochemical reduction of $CO_2$ in aqueous $KHCO_3$ colution between an activity for the product and the nature of Cu electrode, the electrode surface was characterized by using two methods: X-ray photoelectron spectroscopy (XPS) and photoelectron emission (PE) measurement. Electrolyses were performed with Cu electrodes pretreated in several ways. The distribution of the products changed drastically with electrolysis time and the pretreatment method. The features in XPS spectra were closely connected with the product distribution. The oxide film at the electrode surface was gradually reduced to bare Cu metal with electrolysis time, resulting in a variation of the product distribution. PE was measured by verying the wavelength of incident light at several temperatures. The dependence of PE on the measurement temperature changed greatly before and after electrolysis.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.363-372
• /
• 1993

For more accurate height/depth control of the agricultural implements , the soil surface as a reference position should be measured as accurate as possible. A new measurement system using microwave was developed to detect the true soil surface even under plant and/or vegetation. Two-frequency continuous-wave radar was used as the measurement system. It could estimate the distance to the target by measuring the phase difference between two different frequencies continuous-waves which reflected on the target surface. The system performance was evaluated on the barely field where the average height of barley was 91.5 cm. The experimental results showed that the system performance was not affected by the existence of barely. The maximum measurement errors were 8.91 com and 8.44cm for two different experimental plots.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.06a
• /
• pp.34-39
• /
• 2006

An automated surface-strain measurement system, named ASIAS, was developed by using the image processing and stereo vision techniques in the previous studies by the corresponding author and his coworkers. This system has been upgraded mainly to improve the accuracy through image enhancement, sub-pixel measurement, surface smoothing, etc., since the first version was released. The present study has still more improved the convenience of users as well as the accuracy of measurement by processing high resolution images 8 mega pixels or more which can be easily obtained from a portable digital steal camera. It is proved that high resolution image processing greatly decreases the measurement error and gives strain data without considerable deterioration of accuracy even when the deformed grids to be measured and the master grids for camera calibration are captured together in the same image, making the whole process of strain measurement much simpler.

• Korean Journal of Optics and Photonics
• /
• v.20 no.2
• /
• pp.134-140
• /
• 2009

In this study, the influence of surface roughness on light scattering from Au pads on a PCB surface was investigated. Angular distributions of light scattered from Au pads with different surface roughness were measured for several incident angles. Diffusely-scattered light could be separated by using the fact that the amount of specularly-scattered light was directly related to surface roughness. The separated diffuse term was curve-fitted with a physics-based model, and then the related scattering parameters were extracted and compared with measured parameters.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.11
• /
• pp.51-57
• /
• 2001

A light beam reflected from a machined surface generally containes information concerning about its surface roughness. This study examines and proposes a surface roughness measurement technique for on-machine measurement of machined surfaces. The technique is based on the measurement of a reflected laser beam pattern and the statistical analysis of its light intensity distribution. The surface roughness was found to be closely related to the standard deviation of the light intensity on the primary axis of the reflected pattern. An image acquisition device is made up of a laser diode, a half mirror, a screen, and a CCD camera. The exact image with the primary and secondary axes of a reflected laser beam pattern is calculated through such image processing algorithm as thresholding, edge detection, image rotation, segmentation, etc. A median filter and a surrounding light correction algorithm are improve the image quality and reduce the measuring error. Using the developed measuring device the effect of screen materials and workpiece and workpiece materials was investigated. Experimental results regarding to relatively high-quality surfaces machined by grinding, polishing, lapping processes have shown the measurement error is within 10% in the range of $0.1{mu}m~0.8{\mu}m R_q.$Therefore, the proposed method is thought to be effectively used when quick measurements is needed with workpieces fixed on the machine.