• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.7
• /
• pp.108-115
• /
• 1997

In this paper, an algorithm of computing interference-free tool approach directions(visibility cone) with consideration of tool volume at an arbitrary point of a sculptured surface is developed. The surface is first approximated into a polyhedron with smaller subpatches and the tool approach directions are evenly sampled so as to test accessibility. Then the visibility cone is computed by testing if each approach direction is interfered by other surface subpatches. The results are represented as the binary spherical map which transform geometric information on sphere into aogebraic one. The developed algorithm is implemented and tested by several sculptured surfaces, convincing it can be easily used as a tool for not only interference- free tool approach directions but also determining process planning of multi-axis NC machining of sculp- tured surfaces

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1227-1230
• /
• 2003

A roughing process is one of the most important and indispensable shoe manufacturing processes of various types of shoes. This basic process to rough the upper of the shoe is studied to improve the productivity and to reduce the processing time. In this study, the CAM system for shoe roughing is developed. The B-spline surface generated by the developed CAM system ignores the small inclinations of the real roughing surface because the developed roughing tool has potential to rough the roughing surface of the shoe properly. The roughing tool roughs the roughing surface using its side along the generated tool paths. The generated NC codes were applied to 5-axis polishing machine for the test. Experimental results show good evaluation result. The upper of the shoe is roughed properly along the roughing path line and the roughing surface was good to cement the outsole of the shoe.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.683-689
• /
• 1996

5축 가공기는 가공중의 공구자세 변화를 요구하는 복잡한 산업형상의 가공, 혹은 경사 가공을 통한 표면조도 향상등의 목적으로 채용되는 첨예의 공작기계로서 이를 지원하는 CAM연구가 활발히 이루어지고 있다. 그러나, 산업현장에서 흔히 5축 가공기로 일컬어지는 상당수의 5축 가공기는 기구축은 5축을 가지나, 동기제어 축수는 3측인 “선택적 3/5축 가공기”의 형태로서 진정한 의미의 5축가공기와는 근본적으로 다르다. 5축 동기제어를 지원하는 CAM연구는 부분적으로 연구 개발된 상태이나, 선택적 3/5축을 지원하는 CAM 이론은 연구된 바 없으며, 이에 따라 현장에서는 공작물의 셋업을 변경시키는 소위 자동 인덱싱 방식으로 활용하고 있는 실정이다. 본 연구팀에서는 선택적 3/5축 가공기에서 5축 가공을 실현할 수 있는 공구경로 산출 및 제어알고리즘을 개발하고 있으며, 본 논문에서는 (5축 가공 대비) 선택적 3/5축 가공문제의 이론적 특성과 경사가공을 수행하기 위한 알고리즘을 소개하고 시뮬레이션을 통하여 유효성을 보인다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.862-867
• /
• 1997

A 5-axis NC milling technology is presented on ruled surface. Problems in 5-axis NC machining are such as tool interference,tool collision and change of tool attitude,etc. The change of tool attitude causes rotation of cutter and variation of feedrate to overcut part surface. This poor control of tool attitude is the primary problem in multi-axis NC milling. This paper observes ruled surface for control of tool attitude. Ruled surface is composed of directrix and ruling, line of constant magnitude. Directrix corresponds to points on part surface and Ruling cutting tool. Trajectory of tool movement corresponds to ruled surface.

• Korean Journal of Computational Design and Engineering
• /
• v.5 no.4
• /
• pp.393-402
• /
• 2000

Recently 5-axis NC machines are widely used in Korea. Since 5-axis machines have two more degrees of freedom than 3-axis machines, it is very important to find desirable tool positions(locations and orientations) in order to make an efficient use of expensive 5-axis NC machines. In this research an algorithm to determine “optimal” tool positions for 5-axis machining of sculptured surfaces is developed. For given CC(Cutter Contact) points, this algorithm determines the cutter axis vectors which minimize cusp heights and satisfy constraints. To solve the optimal problem, we deal with following major issues: (1) an approximation method of a cusp height as a measure of optimality (2) Identifying some properties of the optimal problem (3) a search method for the optimal points using the properties. By using a polyhedral model as a machining surface, this algorithm applies to sculptured surfaces covering: overhanged surface.

• Korean Journal of Computational Design and Engineering
• /
• v.13 no.5
• /
• pp.382-390
• /
• 2008

Five-axis machining has been applied to manufacture of turbine blades, impellers, marine propellers. Nowadays it extends to mold & die machining, where more productivity as well as added value is expected. The five-axis machining can be divided into positional and continuous, according to the variableness of tool orientation during material removal process. The positional five-axis machining is commonly applied to the regional machining on a whole part surface in mold manufacturing industry, where the tool orientation for each region (area) should be determined to be feasible, that is, avoiding any interference such as machine tool collision, etc. Therefore it is required for a CAM programmer to decide a feasible tool orientation in generating tool-paths on a designated area, because it is a very tedious job to obtain such information by utilizing a commercial CAM system. The developed system generates feasibility data on tool orientation and machining region, which facilitates the CAM programmer's decision on a feasible tool orientation.

• Korean Journal of Computational Design and Engineering
• /
• v.7 no.1
• /
• pp.34-41
• /
• 2002

Five-axis NC machining, in general, is utilized in fabricating impellers, turbine blades, marine propellers that can be machined more effectively rather than three-axis machining. There have been many researches concerning tool interference avoidance, optimization of tool orientation. The C-space or Configuration-space was originated from the robotics area, which depicts interference-free joint-values in motion planning. In the paper we propose an optimizing scheme by which the maximum effective-radius of a face-milling cutter can be achieved for each CC(cutter-contact) point. Also the concept of a C-space for a CC point, the effective-radius map for 5-axis face-milling, and some illustrative examples of marine propeller machining, are presented.

• Journal of the Korean Society for Precision Engineering
• /
• v.32 no.8
• /
• pp.705-711
• /
• 2015

Five-Axis machines can generate undesirable defects such as the undercutting and overcutting errors that frequently occur in the three-axis machining process. It is therefore necessary to develop a program for NC-code generation, whereby the cutter posture is considered to decrease the occurrence of defects. In previous studies, the Easy-Impeller CAM(E-ICAM), an automatic CAM program used for the five-axis machining of impellers, was developed; however, when E-ICAM is used to machine an impeller, it is possible to gouge the hub and blade. Therefore, the aim of this study is the establishment of a formula for each type of endmill to minimize gouging according to the cutter posture, in consideration of several factors that affect accuracy in the machining of an impeller. This study also aimed to improve the performance and accuracy of E-ICAM in the manufacturing of impellers.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.2
• /
• pp.27-33
• /
• 2012

A marine propeller is designed for preventing cavitation priority. Cavitation is a phenomenon which is defined as the vibration or noise by dropping the pressure on the high-speed rotation of the propeller. There has to be a enough thrust on the low-speed rotation for preventing cavitation. Thus, it has to be considered in the increasing of the number of blade and the angle of wing to design the propeller. In addition, flow resistance will be increasing by narrowing the width between blades. So high quality surface roughness of the hub to minimize flow resistance is required. Interference problems with tool and neighboring surfaces often take place from this kind of characteristics of the propeller. During 5-Axis machining of these propellers, the excessive local interference avoidance, necessary to avoid interference, leads to inconsistency of cutter posture, low quality of machined surface. Therefore, in order to increase the surface quality, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. This study, by using a MC-space algorithm for interference avoidance and a MB-spline algorithm for continuous control, is intended to create a 5-Axis machining tool path with excellent surface quality. Also, an effectiveness is confirmed through a verification manufacturing.

• Journal of the Korea Safety Management & Science
• /
• v.11 no.1
• /
• pp.35-41
• /
• 2009

대부분의 사람들은 의식하지 못하지만 세상은 오른손잡이 중심으로 이뤄져 있기 때문에 왼손잡이가 일상적으로 겪는 불편은 상상외로 많다. 우리가 일상에서 많이 사용하는 연장, 주방기구, 사무용품, 가전제품, 가구, 의류, 악기, 의료기기, 스포츠용품, 공공시설 등 이들 대부분이 오른손잡이에게 맞춰져 있어 왼손잡이들은 자신들의 왼팔을 비틀어서 사용하거나 주손이 아닌 오른손으로 부자연스런 자세로 사용할 수밖에 없다. 이에 따라 왼손잡이는 일상생활에 있어서의 상당한 불편을 느낄 뿐만 아니라 작업 능률의 저하, 재해나 상해를 입을 가능성이 높아질 수 있다. 본 연구는 무작위로 선정된 피설문자에 대한 설문 조사를 통하여 손잡이(handedness)와 관련된 통계수치를 제공하고 왼손잡이인 경우 왼손잡이로서 일상생활에서의 불편함, 작업능률의 저하여부, 오른손잡이 전용제품을 사용하여 상해를 입은 경험 등에 대해 조사하였다. 또한 왼손잡이도 편리하게 사용할 수 있으면 하는 제품이나 공공시설 등에 대한 이들의 주관적인 견해에 대해서도 조사하였다. 이를 토대로 왼손잡이를 위한 공구, 주방용품, 문구용품, 스포츠용품, 사무용품 등에 대하여 현재 적용되어 있는 상품에 대한 고찰과 향후 적용 가능 상품 및 공공시설에 대해 제안하였다.