곡면가공시 공구간섭에 따른 미절삭체적의 다단계 NC가공

맹희영,차지경 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

A new efficient intelligent machining strategy named the Steepest Directed Tree method is presented in this study, which makes surface model discrete with triangulation meshes and the cutter paths track along the tree directions. In order to formulate these algorithms practically, it is deduced the multi-stage machining approach of uncut volume caused by cutter gouging in the course of milling using flat end mill. It is systematized the checking process the cutter interference by grouping the 6 kinds of gouging types, which yields the environment of connectivity data lists including CL-data, and then the multi-stage machining strategy, that minimizes uncut area by continuously sequencing the generative subsequent CL-paths, is shamed to determine the second tool path for the next uncut area and to compose the operating multi-stage cutting processes. The completed machining system of curved surfaces is evaluated by testing the practical machining experiments which have various kinds of shape conditions.

구면좌표계식 기구를 이용한 인공치아의 3차원 측정시스템 개발

맹희영,성봉현,Maeng, Hee-Young,Sung, Bong-Hyun 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.6

With recent increased demand for reverse engineering in dental machining, the 3D laser scanner is widely used for inspection of artificial pontic. In order to overcome the optical drawback of laser scanner, such as irregular scatter, direction of beam, and the influence of surface integrity, it is developed in this study a new 3D measuring system for artificial pontic using spherical coordinate system mechanism by point laser sensor, which keeps the direction of beam normal to surface consistently. The comprehensive integrated system is established to evaluate the improvement of accuracy with data acquisition system. The experimental results for measuring a master ball and pontic models shows the excellent form accuracy and repeatability compared with conventional apparatus. Also, these results shows the possibility to apply this system for the measuring purpose within 0.05mm accuracy of pontic at the sharp edge or margin contour, which was difficult to measure at the conventional systems.

곡면모형 Ball End Milling 의 모형화 및 기구해석에 관한 연구

孟喜永 서울産業大學校 1988 논문집 Vol.27 No.1

In this paper, ball end milling mechanism of curved surface model is analyzed to improve the cutting ability and to search for more refined tooling conditions. A general analysis procedure of cutting speed components on the rake face is established. It shows the properties that negative region of speed components occur in tool point and outside edge. And cutting operation angle determination stratagy is analyzed. It is also discussed relationship between geometrical cutting condition and cutting operation angle. The result of numerical procedurewill offer the fundamental materials to progress the cutting force, and stability analysis in curved surface ball end milling process.

초정밀 가공기용 에폭시-그래나이트 재 구조물의 모델링 실험 ( Modelling Experiment of Epoxy-Granite Structures for Ultra-Precision Machines )

맹희영,박영일,원시태,박종권 대한기계학회 1993 대한기계학회 춘추학술대회 Vol.- No.-

볼엔드밀 加工에서 남겨진 커습體積의 仕上加工 特性에 關한 연구

김명수,천상진,맹희영 서울産業大學校 1997 논문집 Vol.46 No.1

The polishing characteristics of machined surface after ball end milling are studied in this paper quantitatively to investigate the optimum machining time including polishing and milling process. The polishing experiments are formulated into the incremental changing task of sand paper meshes bounded by the allowable limit roughness for each abrasive grit size. Testpieces are prepared by milling the flat steel block to have the terraced surface for the different milling crossfeed and cutter size, and polishing device installed on a grinding machine table, which simulates the actual polishing work as specified stroke and acting pressure. The polishing efficiency is investigated during the polishing experiment, and then eventually polishing time is evaluated for the various kinds of conditions, and it is finally analyzed the total machining time which is estimated by adding the milling time to the polishing time of corresponding testpieces. Although the polishing work is shortened as the initial roughness of milled surface becomes small, the total machining time is revealed as the minimum value at a testpiece prepared by milling condition of 1.5mm crossfeed and 20mm cutter size, which means the most economic machining balance between milling and polishing work partitions.

CNC선삭시 주축변위센서를 이용한 편심 가공오차와 절삭력 변화특성의 검출

맹희영 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.1

This paper presents the methodology for measuring eccentricity of the machined cylindrical part using CCS(cylindrical capacitance spindle sensor) signal in the CNC turning process. We use capacitance type sensor to take full advantage of averaging effect by using large capacitance area to encompass the whole side of a sensor. The intentionally proposed initial eccentricity is applied to the experimental testpieces, and their resultant relationships between CCS orbits and eccentricities are investigated. As a result, the possibility as a automatic detection apparatus for the CNC lathe is considered based on the linearities of CCS signal and magnitude of eccentricity of machined cylindrical surfaces.

정전분말코팅 조건에 따른 3D 스캐닝 데이터의 민감도 특성 연구

맹희영,이주봉,김성민 한국전시산업융합연구원 2017 한국과학예술융합학회 Vol.29 No.-

surface to collect the 3D data using an optical 3D scanning device, like metal, rubber, glass materials. Currently, a developing solution is applied to eliminate the reflection of light of a material of a subject, but in the case of a developing solution, it is not only a consumable item but also a subject can be damaged, and it is difficult to remove it after coating. So that, an electro-static powder coating system is developed in this study that can be used as a substitute for the developing solution, and designed the system of the equipment in order to adsorb the electrostatic powder. The system of the electrostatic powder adsorption apparatus for three-dimensional photography is roughly classified into six parts, and includes an injection part for generating powder and voltage and a removal part for collecting and reusing powder sprayed on the subject It is a core part of the equipment system, and in other parts it is divided into a table of subjects, a control unit, a powder storage unit, and an air supply unit. After developing the equipment system, we analyzed and evaluated the data through 3D photography. Evaluation of the shape accuracy of the subject surface and the sensitivity characteristics of the three dimensional data were carried out. As a result, it was verified that the electrostatic powder coating method is more efficient than the developing solution application. In addition to being superior in terms of time and workers, the precision of three-dimensional data was more precisely known than with the developer coating. 백색광 3D 스캐너를 이용하여 금속이나 고무, 유리재질과 같이 매질 표면에서 빛이 난반사나 흡수 또는산란을 일으키는 표면 부위는 스캐닝 데이터의 손실이나 오류를 일으키기 때문에 데이터 수집이 어렵다. 이들 표면은 전통적으로 현상액을 도포하여 난반사가일어나지 않도록 스캐닝하고 있지만 부식이나 변색을유발시킬 수 있으며, 도포 후 완벽하게 세척할 수 없는 어려운 점이 있다. 본 연구에서는 이러한 문제점을 해결하기 위한 장치로서, 정전분말코팅의 원리를 이용하여 3차원 형상 측정을 위한 스캐닝 대상 표면에 정전기를 갖는 분말 입자들이 정전기의 힘으로 얇으면서도 고르게 코팅되도록 하기 위한 장치를 개발하였으며, 이 시스템을 이용하여 난반사 표면에 대한 3D 스캐닝 데이터를 얻을 때생기는 오류를 얼마만큼 줄일 수 있는가를 평가하였다. 피사체 표면에서 빛의 영향으로 데이터의 오류가 나타날 수 있는 3D 데이터의 민감도 특성에 대한 평가와 정전분말 코팅된 표면의 형상정밀도를 분석하였다. 무코팅, 현상액 도포, 정전분말코팅 등의 3가지 경우에 대한 스캔 데이터와 스캐닝 조건 등을 비교한결과, 금속 재질뿐만이 아니라 목재, 고무, 아크릴 등의 부도전체에서도 정전분말코팅의 조건이 3D 데이터수집의 민감도를 높여 주고 있으며, 빛이 흡수되거나고무 재질이나 투과되는 아크릴 재질에 있어서도 전반적으로 민감도는 우수해 짐을 밝힐 수 있었다. 또한 3D 스캔 데이터의 형상정밀도를 평가한 결과에 있어서는 일반적으로 코팅에 따른 형상정밀도의 향상은 투과성을 가진 유리 재질의 경우가 가장 적게 향상되고 있었으며, 금속의 경우보다는 비도전체의 경우가 그 차이가 크게 나타나지 않음도 밝힐 수 있었다

곡면 경계부 미절삭 체적의 잔삭 가공에 관한 연구

맹희영,임충혁,Maeng, Hee-Young,Yim, Choong-Hyuk 한국생산제조학회 2010 한국생산제조학회지 Vol.26 No.2

It is presented in this study a new efficient intelligent machining strategy, which can be used to remove the uncut volume at the boundary region of curved surfaces caused by cutter interference. The geometric form definitions and recognition of topological features of the surface triangulation mesh are used to generate cutter paths along successive and interconnected steepest pathways, that minimize the cusp height left after flat end milling. In order to machine the uncut volume gradually, the z-map cutter centers are adjusted to avoid cutter interference for the 6 kinds of avoidance types. And then, the generative subsequent paths are sequenced to determine the second step cutter paths for the next uncut volume. For the 2 kinds of test models with convex and concave surface region, the implemented software algorithm is evaluated by investigating the residual swelling of uncut volume for each machining step.

자유곡면 모형의 CAD/CAM 및 시뮬레이션

孟喜永 서울産業大學校 1987 논문집 Vol.25 No.1

In this paper, sculptured surface is represented by 3D point data and cutter path for NC machining is generated from the process planning of it. The following details are advanced in the course of their implementation. Cell-constructed geometric model is applied to the integration and interface of CAD, CAPP, and CAM uniformly. The end condition of surface boundary is expressed by tangent vector component of pivot circle. The regions which the cutter gouges large curvatured parts are restricted with the principal curvatured line. It is used variable feedrate estimation sheme to solve the cut-segmentation problem and to decrease the cutting time. As a results, it is developed software package, with which can conduct a CAD/CAM of sculptured surface model in the personal computer without economical burden.

철도 차량의 연결기 시스템의 충돌시뮬레이션

맹희영,김진성,박영일 한국생산제조학회 2013 한국생산제조학회지 Vol.22 No.3

In this study, a collision simulator for rolling stock that considers the plastic deformation of the car body and the dynamic characteristics of a coupler system was developed using Matlab/Simulink. Normally, a coupler system has functions for both connecting the individual car bodies and absorbing the impact energy. A coupler system is composed of a rubber buffer, hydraulic buffer, and deformation tube elements. The coupler system should protect the car body and prevent damage when the shunt speed is less than 10 km/h, which is the regulation speed based on the safety rule for rolling stock. However, if the shunt speed is greater than 10 km/h, a car body is plastically deformed. Therefore, the modeling of the plastic deformation of a car body should be included in a simulator. This collision simulator can provide the design parameters for a coupler system and car body.