• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.53-57
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• 2002

The chatter to raise grinding operating is reduce the precision and the quality. In this study, In reply to AE signal and the normal force generated in the grinding operating were measured (1) the amplitude in the mathematical model of the normal force is the form as to transform an exponential (2) the chatter growth is minus point of an exponent. (3) From the observed wheel aspect after the chatter growth, it was to investigated the concern of the chatter growth and the wheel life.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1020-1024
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• 1997

Recently the use of ceramic materals has been greatly increased in the industries. But machining of the ceramics is quite unproductive because of their high stength,high hardness,and brittleness. The efficiency of the grinding operation of ceramics depends on the preparation of diamond grinding wheel, i.e.,truning and dressing. This paper describes some experimental results on the dressing conditions of diamond grinding wheel. The dressing performance is evaluated by the magnitude of normal grinding force. The better dressed wheels result in the lower normal grinding forces. The dressing performances of copper plate and aluminum oxide dressing stick are compared. The optimum dressing conditions including the grit size of dressing sticks, the depth of the dressing operation, and the dressing speed qre determined.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.787-792
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• 2000

Ultra-abrasives such as diamond and CBN have used to maintain accuracy and form deviation for superalloy etc. This study contains the dry cylindrical grinding of metals with Vitrified-bond CBN wheel. For various conditions of grinding speed, workpiece speed, grinding depth and feed speed of table, the grinding resistance, the surface roughness, and the material removal are measured and discussed. The results are as follows.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.680-695
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• 1998

The objective of this study is to optimize the responses of the creep feed ceramic grinding process simultaneously by an off-1ine multicriteria optimization methodology. The responses considered as objectives are material removal rate, flexural strength, normal grinding force, workpiece surface roughness and grinder power. Alumina material was ground by the creep feed grinding mode using superabrasive grinding wheels. The process variables optimized for the above objectives include grinding wheel specification, such as bond type, mesh size, and grit concentration, and grinding process parameters, such as depth of cut and feed rate. A weighting method transforms the multi-objective problem into a single-objective programming format and then, by parametric variation of weights, the set of non-dominated optimum solutions are obtained. Finally, the multi-objective optimization methodology was tested by a sensitivity analysis to check the stability of the model.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.103-108
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• 1999

A problem in the grinding with a small diametric wheel is the decrease of wheel speed. In order to resolve this problem, an accelerating unit which increases the wheel speed is recommended. In this paper, the accelerating effect of an accelerating unit has been investigated through the side-cut grinding experiments performed with a vitrified bonded CBN wheel in a machining center(MC). The static stiffness, normal force, and machining error were measured in the experiments. As the accelerating unit is attached on the column of machining center, the static stiffness of tool system is largely decreased. But as the wheel speed increased by the accelerating unit, this problem is overcome and machining efficiency is improved. The lesser the quill stiffness was, the higher the accelerating effect became.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.2
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• pp.102-107
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• 2017

This study focuses on the effect of the elasticity modulus of jig material on blade edge shape in the grinding process of a sapphire medical knife. The ELID grinding process was applied as the edge-grinding method for sapphire material. Carbon steel and copper have been selected as the hard and soft jig materials, respectively. The blade edge created by ELID grinding was measured by a surface roughness tester and optical microscope. The shape of the ground edge and surface roughness were compared using the measurement results. As a result, it was found that chipping in the blade edge of the sapphire knife occurred more than in the case of jig material with a high-elasticity modulus because of the high normal force in the grinding process. Moreover, the maximum height surface roughness, $R_{max}$,of the ground surface was higher in the case of the jig material with a high-elasticity modulus due to the difference in elasticelongation. It was considered to lead to chipping from the notch effect.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.102-109
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• 1996

In this paper, we present a new approach for the automation of deburring process. An algorithm for teaching skills of a human expert to a robot manipulator is developed. This approach makes use of TSK fuzzy mode that can wxpress a highly nonlinear functional relation with small number of rules. Burr features such as height, width, area, grinding area are extracted from image processing by use of the vision system. Grinding depth, repetitive number and normal grinding force are chosen as control signals representing actions of the human expert. It is verified that our proposed fuzzy model can accurately express the skills of human experts for the deburring process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.339-345
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• 2002

연삭 가공시 발생하는 채터는 정밀도 및 품질을 저하시킨다. 본 논문에서는 연삭가공시 작업시간에 따른 연삭 법선력 및 AE 신호의 거동을 관찰함으로써 (1) 연삭법선력의 수학적 모델은 그 진폭이 지수적으로 변하는 형태이고, (2) 그 지수가 음(minus)이 될 때가 체터 발생시점이며 (3) 이를 토대로 이론적으로 (2)를 규명할 수 있는 방법을 고찰하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.457-465
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• 1988

The inside contact characteristics in abrasive belt drives were investigated analytically and experimentally for (1) driver pulley contact wheel and (2) driven pulley contact wheel. The concentrated contact forces in the grinding zone divided the entire belt-pulley contact are by three distinct areas and the tangential friction forces in the active areas caused the normal forces to change, which resulted in the different belt force distribution compared with those of the ordinary flat belt drives. The experimental results for the normal pressure (belt tension) distribution were in good agreement with the theoretical results.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.205-212
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• 1987

The purpose of this study was to investigate the duration of the silent period of the masseter muscle in normal subjects after experimental bruxism. The material for this study consisted of 9 male subjects with an age range of 22-24 years who showed normal occlusion clinically and were free from any history or symptoms of temporomandibular joint dysfunction. A jaw-jerk was stimulated by tapping the mandibular symphysis during maximal voluntary clenching with a solenoid-driven hammer. And three separate silent period records were made from the left masseter muscle at the following times: at normal state, after experimental bruxism, 1 week after bruxism. The following conclusions were obtained: 1. The average value of the duration of masseteric silent period during maximal voluntary clenching was $33.62{\pm}1.86msec$ when tap force of approximate 650g was applied at normal state. 2. After experimental tooth grinding for 30 minutes, the duration of masseteric silent period increased to $46.29{\pm}4.40msec$. 3. Comparing the duration of silent period measured at normal state with that measured after 1 week, the duration of silent period showed reproducibility.