유연생산 시스템 구축을 위한 공작물 자동교환 유닛의 수평 이송 기구 설계에 관한 연구(파트 2)

박후명(Hoo-Myung Park),성재경(Jae-Kyung Sung),이용중(Yong-Joong Lee),하만경(Man-Kyung Ha) 한국기계가공학회 2008 한국기계가공학회지 Vol.7 No.2

The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. To achieve this goal, this study designed a horizontal transfer as the second project continued to the first project that designed a upward and downward traverse unit. A horizontal traverse unit shows a symmetric structure and consists of frame, which consists of four unit tools, motor and reducer, which are fixed at a frame, operation unit with pinions, first traverse unit, and second traverse unit. Constraint conditions based on the operation mechanism with these elements were configured and obtained following results after modeling a model for a traverse motor. In the kinematic expression of sliding motion with one degree of freedom, the sliding motion is constrained. Also, the rack 3 installed at a frame is used to configure possible kinematic constraint conditions of the rack 2 according to the rolling motion of the pinion 2 in the first traverse unit. In addition, the moment of inertia that is a type of kinetic energy in a converted horizontal traverse unit in the side of the reducer can be applied to introduce the moment of inertia of a converted horizontal traverse unit in the side of the reducer by using the sum of kinetic energy in the rack and pinion, which is a part of the horizontal traverse unit. Also, the equation of motion of the converted upward and downward traverse unit in the side of the motor using the equation of motion of the motor. Furthermore, the horizontal traverse unit predetermines the mass of the first and second traverse unit and applied load including the radius and reduction ratio of the pitch circle in the pinion 1 and applied load to the rack 2. Then, a proper motor can be determined using several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. In future studies later this study, a simulation that verifies the results of the previous two stages of studies using a finite element method.

유연생산 시스템 구축을 위한 공작물 자동교환 유닛의 상하 이송 기구 설계에 관한 연구(파트 1)

박후명(Hoo-Myung Park),강진갑(Jin-Kab Kang),이용중(Yong-Joong Lee),하만경(Man-Kyung Ha) 한국기계가공학회 2008 한국기계가공학회지 Vol.7 No.2

The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. In order to perform this objective, a upward and downward traverse unit in which a unit that consists of a motor and reducer, chain and sprocket wheel, and upper and lower base employed in an automatic object changer unit performs sliding contact motion in a frame was designed. To achieve this design, constraint conditions for the upward and downward traverse unit first designed. Then, an operation mechanism was designed and that was introduced as a sum of kinetic energy for the sprocket wheel and upper and lower base based on the moment of inertia, which is the kinetic energy of the converted upward and downward traverse unit in the side of the reducer. In addition, The work required to rotate the converted upward and downward traverse unit in the side of the reducer by one revolution can be calculated using the sum of work that is required in the sprocket wheel and upper and lower base that is a part of the upward and downward traverse unit. Furthermore, the converted equation of motion in the side of the motor can be introduced using the equation of motion using the converted upward and downward traverse unit in the side of the motor. Then, Then, a proper motor can be determined using predetermined specifications employed in the motor and several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. Also, a design of a horizontal traverse unit that performs sliding motion on a upward and downward traverse unit and simulation that verifies the results of this design are required as a future study.

연삭력 변화량이 공작물의 형상오차에 미치는 영향

지용주,이상진,박후명,오상록,하만경,Chi, Long-Zhn,Lee, Sang-Jin,Park, Hoo-Myung,Oh, Sang-Lok,Ha, Man-Kyung 한국기계가공학회 2004 한국기계가공학회지 Vol.3 No.2

A real depth of cut in deformed zone has larger than an ideal depth of cut. So the heat generated during grinding operation makes the deformation of a workpiece surface as convex farm. Consequently the workpiece surface remains a geometric error as concave form after cooling In this study, the grinding force and the geometric error were examined in surface grinding. Through magnitude and mode of geometric error were evaluated according to grinding conditions, an optimal grinding condition was proposed to minimize the geometric error In addition, the relationship between the geometric error and the grinding force was examined. Due to least square regression, It was possible to predict the geometric error by using the grinding force.

비철 금속 보온로 용탕 자동공급 장치 개발

이용중(Yong-Joong Lee),박후명(Hoo-Myung Park),이상진(Sang-Jin Lee) 한국기계가공학회 2007 한국기계가공학회 춘추계학술대회 논문집 Vol.2007 No.-

The objective of this development project is to localize an automatic molten metal supplier that has been distributed by WESTOMAT, Germany, throughout the world. To achieve this purpose, an energy-saving pressurized dosing furnace and molten differential pressure control system that is able to automatically supply a determined quantity of aluminum molten metal were developed. The localized equipment was installed in a site. Also, the results of the test operation of this equipment can be summarized as follows: It was able to improve the productivity because there were small decreases in supplying speeds and small losses in wastes compared to the existing mechanical molten metal supplier. Also, it was able to minimize the cost in maintenances due to the direct application of high temperature molten metals to molds. In addition, there were small energy losses due to the use of high thermal insulators compared to the existing reverberating furnace and able to prolong the life-time of furnaces and produce good quality nonferrous metals because it represented small carbon refractories and alumina in applied molten metals. Furthermore, it demonstrated no particular differences by objectively comparing it with the product by WESTOMAT.

공정최적화를 통한 정형외과용 캐스팅 테이프 개발

허광태(Kwang-Tae Hur),박후명(Hoo-Myung Park),곽재섭(Jae-Seob Kwak),하만경(Man-Kyung Ha),하경호(Kyoung-Ho Ha) 한국기계가공학회 2008 한국기계가공학회 춘추계학술대회 논문집 Vol.2008 No.-

Recently, polyurethane pre-polymer has been used widely in the social life. In this paper, evaluation of parameters for polymerization process was carried out using design of experiments. As a result, the effect of each parameter affected by viscosity and residual NCO of pre-polymer was found. Optimization of polymerization process was performed. and the these results were applied to produce casting tape having a better performance.

고속가공에서의 열 발생 특성

이상진(Sang-Jin Lee),박후명(Hoo-Myung Park),이상태(Sang-Tae Lee),하만경(Man-Kyung Ha) 한국기계가공학회 2006 한국기계가공학회 춘추계학술대회 논문집 Vol.2006 No.-

The term 'High Speed Machining' has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent year, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. With increasing cutting speed used in modern machining operation, the thermal aspects of cutting become more and more important. It not only directly influences in rate of tool wear, but also will affect machining precision recognized as thermal expansion and the roughness of the surface finish. Hence, one needs to accurately evaluate the rate of cutting heat generation and temperature distributions on the machining surface. To overcome the heat generation, we used to cutting fluid. Cutting fluid plays a roles in metal cutting process. Mechanically coupled effectiveness of cutting fluids affect to friction coefficient at tool-work-piece interface and cutting temperature and chip control, surface finish, tool wear and form accuracy. Through this study, we examined the behavior of heat generation in high-speed machining and the cooling performance of various cooling methods.

반응표면분석법을 이용한 연삭가공물의 형상오차 예측

지용주(Long-Zhu Chi),이상진(Sang-Jin Lee),박후명(Hoo-Myung Park),황영모(Yung-Mo Hwang),곽재섭(Jae-Seob Kwak),하만경(Man-Kyung Ha) 한국기계가공학회 2005 한국기계가공학회 춘추계학술대회 논문집 Vol.2005 No.-

유연생산 시스템 구축을 위한 공작물 자동교환 유닛 설계

박후명,이용중,이상진,하만경 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

The objective of this study is to develop an automatic object changer unit to improve processing problems existed in the conventional horizontal machining center. In order to perform this objective, a upward and downward traverse unit in which a unit that consists of a motor and reducer, chain and sprocket wheel, and upper and lower base employed in an automatic object changer unit performs sliding contact motion in a frame was designed. To achieve this design, constraint conditions for the upward and downward traverse unit first designed. Then, an operation mechanism was designed and that was introduced as a sum of kinetic energy for the sprocket wheel and upper and lower base based on the moment of inertia, which is the kinetic energy of the converted upward and downward traverse unit in the side of the reducer. In addition, The work required to rotate the converted upward and downward traverse unit in the side of the reducer by one revolution can be calculated using the sum of work that is required in the sprocket wheel and upper and lower base that is a part of the upward and downward traverse unit. Furthermore, the converted equation of motion in the side of the motor can be introduced using the equation of motion using the converted upward and downward traverse unit in the side of the motor. Then, Then, a proper motor can be determined using predetermined specifications employed in the motor and several parameters in the upward and downward traverse unit in order to verify such predetermined specifications. Also, a design of a horizontal traverse unit that performs sliding motion on a upward and downward traverse unit and simulation that verifies the results of this design are required as a future study.

실험계획법을 이용한 연삭가공물의 표면거칠기 분석

지용주,이상진,박후명,곽재섭,하만경 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

A measure for good products manufactured by grinding process is the surface roughness that is affected by a lot of operating parameters such as types of abrasive, grain size, bond material, wheel speed, table speed, depth of cut, hardness of workpiece and stiffness of grinding machine. In this study, an application of the design of experiments was tried for evaluating the effect of operating parameters on the surface roughness. The workpiece was a high speed tool steel(SKH5I) and the surface grinding was conducted. In order to obtain the best surface roughness within constraints of the working range, the optimal grinding conditions were selected. The usefulness of this method was evaluated by the statistical strategy.