• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.44-54
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• 1991

A Study was made on falnk wear in carbide tools in turning SUS304 steel. When an austenitic stainless steel (SUS304 steel) is cut with the tool, saw-toothed chip are produced. It is found that machining SUS304 steel would make a tool worn fast. For increasing productivity, tool wear has to be predicted and controlled. An amended cutting geometry consisting of a negative rake angle ($-6^{\circ}$ ) and a high clearance angle ($-17^{\circ}$ ) is proposed for decreasing carbide tool wear (flank) in the machining of SUS304 steel. The amended cutting geometry is found to make the flank wear lower than a general cutting geometry (rake angle $6^{\circ}$ , clearance angle $5^{\circ}$). The effects of the three cutting variables (cutting speed, feed, tool radius) on the flank wear analyzed by fiting a simple first-order model containing interaction terms to each flank wear parameter by means of regression analysis and the predicted from first-order regression analysis model equation of flank wear.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1153-1160
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• 2010

A circular plate is the main part of a circular saw blade, which is widely used in industrial cutting tools. In experiments using a circular saw containing slots, we observed that a number of natural frequencies are simultaneously emerged in specific frequency regions. The interesting phenomenon is called the frequency convergence. Effects of design parameters such as the number, the length and the width of slots, on the frequency-convergence phenomenon are analyzed by FEM simulations using ALGOR. The frequency-convergence phenomenon will be intensified when the number, length and width of slots increase.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.263-265
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• 2003

The transverse crack, a type of cold crack, occurs perpendicular to the axis of the weld interface, longitudinal residual stresses ($\sigma$k direction) are more important in transverse crack occurrence from my own experience. Specimens were fabricated and welded under actual construction conditions, and then residual stresses of longitudinal stresses were measured for different welding conditions with SAW and FCAW process. The residual stress values for the specimen welded Interpass temperature below 30$^{\circ}C$ was higher than the specimen welded interpass temperature of 100～120$^{\circ}C$. And also the residual stress values for a specimen measured at weld surface, as welded condition, was higher than that of longitudinal residual stresses that was measured from a small test piece, due to the residual stress was relieved in the process of the cutting and machining. Transverse weld cracks were detected in the area of the maximum residual stresses both SAW and FCAW process.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.29-34
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• 2006

In this paper, the mechanical characteristics of ultrasonic cold forged technology (UCFT) used for the trimming knife and the effects of ultrasonic vibration energy (UVE) into the trimming process on the state of the strip cutting face were studied. And a diagnosis system to quality control for trimming knife and strip cutting face was developed and installed in plant. By the plant application of UCFT, service life of knife was more increased over 100% than that of conventional knife. And using the developed diagnosis system, the knife breakage and saw ear have been perfectly detected and quality control of trimming face is obtained effectively.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.508-511
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• 2011

Dust released from the rotating timber cutting process causes various kinds of diseases as well as safety issues. Although there were lots of efforts to reduce the amount of dust by installing large-sized dust collectors or by using expensive high-quality cutters, they proved to be not so effective. In this study we want to modify and improve the design of the rotary cutter system to prevent dust from being released to the environment as possible by using computational fluid dynamics (CFD) analysis. We have developed CFD models of the conventional cutter and several design modifications. Through the CFD analysis the characteristics of the air flow was predicted, and then the behavior of dust produced during the cutting process was analyzed for different designs. The most efficient design feature to capture dust inside the cutter as much as possible was chosen based on the CFD analysis results. Finally the prototype of the ratary saw machine was constructed and tested to check the dust capturing efficiency, which result is reasonably consistent with the predicted performance through the CFD analysis.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.281-287
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• 2016

Purpose: The purpose of this study is to develop a walking-type two-row sesame reaper, which can simultaneously perform the cutting and collecting of sesame plants and other crops like perilla and soybean. Methods: The factors involved in reaping sesame were determined experimentally in order to design a prototype of the sesame reaper. The prototype is made up of four parts for cutting, conveying, collecting, and running. The height of two disc-plate saw blades on the cutting part is adjusted by an adjusting wheel, and peripheral speed is adjusted in accordance with the running speed. The conveying belt of the conveying part can be tilted from $0^{\circ}$ to $90^{\circ}$. The collecting part extracts a predetermined amount of transferred sesame plants. The prototype was used to evaluate the performance at different working speeds, so that the work efficiency can be calculated. Results: The center of gravity of the sesame plants was 900 mm, measured from the end of the cut stem. The diameter of the disc-plate saw blade was determined to be 355 mm, peripheral speed was 20.4-32.7 m/s, and the picking height of the conveying belt for sesame was 130 mm. The performance of transfer and collection of the sesame, when the insertion angles were $60^{\circ}$ and $90^{\circ}$, proved to be excellent. However, when the angle was over $120^{\circ}$, the performance was only 75-80%. The performance was at 100% efficiency when the ratio between running speed and conveying belt speed of the prototype was 1:2, which seems to be the ideal ratio for the sesame reaper. Conclusions: A sesame reaper was developed, which can integrate the processes of cutting, conveying, and collecting, by investigating and considering various factors involved in the reaping process. The sesame reaper can reduce the costs for yielding and producing sesame due to its highly efficient performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.1
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• pp.120-130
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• 1994

The leadwire cutting machine that has been used recently cuts leadwires by putting one-side force with the same priciple as a saw, and applies a stress at soldered part of PCB. Because the stress becomes one cause of contact-defect, a leadwire cutting robot that cuts leadwire-site with nipper and does not apply stress is considered, In this paper a technique of detecting leadwire-site is studied for the purpose of using on automatic leadwire cutting robots. A technique deriving 2-dimensional site-information with many I-dimensional binary data of perspective front-view of PCB taken from various direction was proposed. Simulation and experiments were done under the same condition each other and a small universal PCB was choosen as an experimental object. As a result of simulations and experiments, the proposed technique turns out to be very useful for automatic leadwire cutting robots.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.469-474
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• 1999

The object of study is analysis to joint crack behavior of cracked joint concrete pavement. In the new constructing concrete pavement, joint crack behavior was compared general joint depth D/4 with joint depth D/3 and D/5 that it's environmental effects changed temperature and humidity. After joint saw cutting joint section was predicted crack at joint depth D/5 test section from the result for monitoring development of crack. In the setting of data logger system of the joint section, it's data compared see with the naked eye. In the research, development of crack at the joint section should effect to joint saw timing latter than joint depth. This performance could be the minimum of deterioration to the early curing. In this research, At new constructing of joint concrete pavement of highway, the monitoring system be setting after finished paving and joint sawing. The system and see with the naked eye could be analysis to pavement behaviors from collecting data at the test section. This system could be monitoring shot term and long term. In this report, joint section of crack behavior analysis used to collected data during a month after paving and joint sawing.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.45-54
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• 2014

The average injury rate in sawmilling industry for the last 5 years is 4.99%, which means that more than 200 injuries have occurred in that industry every year. Because the first step in risk assessment is the hazard identification, it is very important to know how to define the hazard and nature of harm. We analyzed 643 accident records of three years(2010-2012) and carried out site survey for the same cases. As a result, the most common types of work at the time of injury in sawmilling industry were removing jammed wood 81(12.8%), wood carrying task 52(8.1%), wood cutting 49(7.6%), travelling table log band saw 41(6.4%), maintenance 37(5.8%) etc. In addition, there were statistically significant differences in some analysis factors such as injured body parts, employment size, and handling material among different working places. Therefore, it is concluded that differentiated prevention efforts are necessary in each workplace.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.6
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• pp.225-229
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• 2011

Most of the silicon cutting methods using the multi-wire with the slurry injection have been used for wafers of the crystalline solar cell. But the productivity of slurry injection cutting type falls due to low cutting speeds. Also, the direct contact with the metal wire and silicon block increases the concentration of metallic impurities in the wafer's surface. In addition, the abrasive silicon carbide (SiC) generates pollutants. And production costs are rising because it does not re-use the worn wire. On the other hand, the productivity of the cutting method using the diamond coated wire is about 2 times faster than the slurry injection cutting type. Also, the continuous cutting using the used wire of low wear is possible. And this is a big advantage for reduced production costs. Therefore, the cutting method of the diamond coated wire is more efficient than the slurry injection cutting technique. In this study, each cutting type is analyzed using the surface characteristics of the solar wafer and will describe the effects of the manufacturing process of the solar cell. Finally, we will suggest improvement methods of the solar cell process for using the diamond cutting type wafer.