• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.4
• /
• pp.83-90
• /
• 2014

The spiral up milling of an aluminum alloy was performed in this study. In accordance with the cutting condition, the surface roughness behavior and significance of the research with regard to specific factors were analyzed. The cutting speed, feed, and depth of the cut were found to be statistically significant. A higher cutting speed improved the surface roughness. On the other hand, as the feed and depth of the cut increase, the surface roughness decreases. An interaction effect between the feed and depth of the cut was detected. According to the surface roughness in relation to the cutting conditions, the model showed non-linear behavior.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.04b
• /
• pp.52-57
• /
• 1995

In order to suggest the proper cutting conditions of the CNC milling machining for the free-from surface, some experiments were carried out. In experiments, the influence of cutting conditions on the inclined spherical surface were examined by geometrical anlysis. In thos study, the roundness and cutting force were measured to know the effect of several cutting conditions on the machined surface and the cutting characteristics were carefully investigated. As the result, it was appeared that rigidder tool must be used and the cutting speed must be maintained constantlyfor more effective machining. It can be also known from the experiments that the improved machining surface obtained under about 80 degree, but coarse surface obtained over about 80 degree because of the existance of immproper shape of ball-end mill at the extreme portion.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.11
• /
• pp.89-95
• /
• 2019

In this research, the effect of roughing on tool load through bottom-up machining is investigated through actual machining. Generally, through the use of high-speed machining technology, machining methods, such as general roughing, operate by deepening the cutting depth for as long as the tool is able to withstand it, giving a slower feed rate, less cutting depth, and faster feed. However, when the cutting depth is deep, there is a problem in that the stepped shape of the cutting area is increased (e.g., by the shaking of the tool or the chipping load). However, if the cutting is performed less, the cutting time becomes relatively long. To compensate for these drawbacks and extend the service life of the tool, economic efficiency needs to be secured.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.4
• /
• pp.87-93
• /
• 2021

The mold industry is competitive, and mold should be processed under optimal conditions for efficient processing. However, the cutting conditions of the ball-end mill, which are a major factor in mold processing, are mostly set empirically, and considerable research is required for increasing the tool life and processing accuracy. In this study, a tool dynamometer and an eddy current sensor were used along with NI-DAQ, a data acquisition device, to obtain characteristic values of the cutting force and tool deformation during the ball end-mill machining of inclined surfaces at a machining center. The cutting force and tool deformation were measured in an experiment. It was found that the tool received the greatest cutting force at the end of the machining process, and the deformation of the tool increased rapidly. Furthermore, the cutting force tended to increase with the angle and number of rotations. The deformation increased rapidly during the machining of a 45° inclined surface.

• 월간 기계설비
• /
• s.246
• /
• pp.30-35
• /
• 2011

정부는 중소건설업체의 공공공사 입찰참여를 확대하기 위해 주계약자 공동도급제도를 확대 시행하고 혁신도시건설사업에 지역의무공동도급을 확대하기로 했다. 대형건설사의 입찰참여 하한액을 상향하고 최저가공사의 저가투찰을 막기 위한 보완방안도 마련했다. 정부는 지난해 12월 8일 이명박 대통령 주재로 개최된 '제76차 국민경제대책회의'를 열고 이같은 내용의 공공부문 동반성장 추진대책을 확정했다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.1
• /
• pp.95-103
• /
• 2015

This paper presents the effects of the tool shape on the geometrical characteristics of flat end-milled side walls. A tool shape is characterized by such parameters as helix angle, number of cutting edges, and diameter. The geometrical characteristics of the side walls are represented by the surface profiles in the feed and axial directions, which are orthogonal to each other. The geometrical defects in each direction are estimated based on the instantaneous apparent cutting areas, which are represented by the interference area between the tool and workpiece and that between the cutting edge and workpiece. It is confirmed that a geometrical defect in the feed direction is formed when the tool leaves the workpiece and the curvature of the tool path changes. Defects in the axial direction are also found in the side walls, except for the defect zone in the feed direction. An up-cut using an end-mill with a steeper helix angle, a greater number of cutting edges, and a smaller diameter are thus found to improve the geometrical accuracy of end-milled side walls.

• Journal of the Korean Society of Industry Convergence
• /
• v.4 no.3
• /
• pp.257-261
• /
• 2001

이 연구는 밀링가공시 체터진동을 억제하기 위하여 부등각 앤드밀(나선각이 서로 다른 앤드밀)을 사용하여 절삭가공을 수행 한 후, 그 가공특성을 고찰한 것으로 가공표면의 기하학적 오차를 일반적으로 사용하는 등각 엔드밀에 의한 값과 실험에 의해 비교 검토한 결과, 두 엔드밀 모두 가공표면의 기하학적 오차는 유사함 나타내고 있으나, 부등각 엔드밀의 절대오차는 등각 엔드밀 보다 더 적은 경향을 나타내고 있다. 이들의 오차는 상향절삭보다 하야절삭 가공했을 때가 더 큰 것으로 나타났다. 더구나, 등각 엔드밀과 부등각 엔드밀과의 절대오차가 다르게 나타난 것은 밀링가공시 사용한 절삭날 인선에 의하여 완전히 의존되어지며, 또한 다른 나선각에 의해 기인된 각각의 절삭날에 대한 절삭날당 이송비의 변화에 의한 원인이라는 것을 명백히 알 수 있었다.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.4 s.97
• /
• pp.220-228
• /
• 1999

The machining accuracy has been improved with the development of NC machine tools and cutting tools. However, it is difficult to obtain a high degree of accuracy when machining deep pocket with long end mill, since machining accuracy is mainly dependant on the stiffness of the cutting tool. To improve surface accuracy in machining deep pocket using end mill, the performance by down cut and up cut is compared theoretically and experimentally. To verify usefulness of up milling, various experiments were carried out. As a result, it is found that up milling produce more accurate surface than down milling in machining deep pocket. For effective application of up milling, various values in helix angle, number of teeth, radial depth of cut and axial depth of cut are applied in experiment.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.6
• /
• pp.58-63
• /
• 1998

There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

• 한국IT서비스학회:학술대회논문집
• /
• 2009.11a
• /
• pp.401-404
• /
• 2009

정보화 시대에서 유비쿼터스 시대로 접어들면서 현실세계에서의 데이터를 정보로 상향시킬 수 있는 기반 기술과 메커니즘이 발전하고 있으며, 이러한 기술적 노력의 이환으로 현실 세계의 실증정보를 가공전의 데이터 형태로 창출하는 기술에는 센서기술(Sensor Technology)이 있으며, 현재 센서기술은 현실 세계의 실증 정보를 수집하는 차원을 넘어서 이들간의 클러스터링을 형성하고 형성된 클러스터링을 기반으로 데이터 라우팅을 통해 가공 메커니즘(Processing Mechanism)을 제공하는 시스템으로 전달되고 이렇게 전달된 데이터와 가공 메커니즘에 의해 서비스를 통해 정보 수요자에게 전달된다. 본 논문에서는 센싱된 데이터를 웹서버를 통해 서비스가 될 수 있는 구조에 대해서 설계 및 제안을 하였다. 또한 본 논문에서는 센싱기술과 센서네트워크, 그리고 웹 서비스라는 일련의 구조를 설계 및 구현시 고려하여야 할 사항 및 발전방향에 대해서 언급한다.