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심기중,유종선,유기현,정진용,Sim, Ki-Joung,Yu, Jong-Sun,Yu, Ki-Hyun,Cheong, Chin-Yong 한국기계가공학회 2004 한국기계가공학회지 Vol.3 No.1
Machining error is defined the normal distance between designed surface and actual tool path with tool deflection. This is inevitably caused by the tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, tool deflection is usually known as the most significant factor of machining error. Tool deflection problem is analyzed using Instantaneous horizontal cutting forces. The high quality and precision of machining products are required in finishing. In order to achieve these purposes, it is necessary work that decrease the machining error. This paper presents a study on the machining error caused by the tool deflection in ball end milling of 2 dimensional surface. Tool deflection model and simple machining error prediction model are described. This model is checked the validity with machining experiments of 2 dimensional surface. These results may be used to decrease machining error and tool path decision.
심기중(Ki-Joung Sim),유종선(Jong-Sun Yu),정진용(Chin-Yong Cheong),서남섭(Nam-Sub Suh) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.7
This paper presents an experimental study on the dimensional error in ball-end milling. In the 3D free-formed surface machining using ball-end milling, while machining conditions are varied due to the Z component of the feed and existing hemisphere part of the ball-end mill, the mechanics of ball-end milling are complicated. In the finishing, most of cutting is performed the ball part of the cutter and the machined surface are required the high quality. But the dimensional errors in the ball-end milling are inevitably caused by tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, the most significant one of dimensional error is usually known as tool deflection. Tool deflection is related to the instantaneous horizontal cutting force and varied the finishing cutting path. It lead to decrease cutting area, thus resulting cutting forces but the dimensional precision surface could not be obtained. So the machining experiments are conducted for dimensional error investigation and these results may be used for decrease dimensional errors in practice.
류시형(Shi Hyoung Ryu),유종선(Jong Sun Yu) Korean Society for Precision Engineering 2009 한국정밀공학회지 Vol.26 No.4
The feasibility of electrochemical drilling and milling on stainless steel are investigated using tungsten microelectrode with 10μm in diameter. For the development of environmentally friendly and safe electrochemical process, citric acid solution is used as electrolyte. A few hundred nanoseconds duration pulses are applied between the microelectrode and work material for dissolution localization. Tool fracture by Joule heating, micro welding, capillary phenomenon, tool wandering by the generated bubbles are observed and their effects on micro ECM are discussed. Occasionally, complex textures including micro pitting corrosion marks appeared on the hole inner surface. Metal growth is also observed under the weak electric conditions and it hinders further dissolutions for workpiece penetration. By adjusting appropriate pulse and chemical conditions, micro holes of 37μm in diameter with 100μm in depth and 26μm in diameter with 50 μm in depth are drilled on stainless steel 304. Also, micro grooves with 18 μm width and complex micro hand pattern are machined by electrochemical milling.
제5차 대한간학회 춘계학술대회 초록집 : 경쟁적 역전사-중합효소연쇄반응과 DNA-ELISA법을 이용한 C형 간염 바이러스 RNA 정량
서강석 ( Seo Gang Seog ),주영은 ( Ju Yeong Eun ),김현수 ( Kim Hyeon Su ),유종선 ( Yu Jong Seon ),김세종 ( Kim Se Jong ),기승정 ( Gi Seung Jeong ),임우현 ( Im U Hyeon ),서순팔 ( Seo Sun Pal ) 대한간학회 1999 Clinical and Molecular Hepatology(대한간학회지) Vol.5 No.1(S)
심기중,유종선,서남섭 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2003 工學硏究 Vol.34 No.-
This paper presents a theoretical analysis to estimate the undeformed chip thickness required for cutting force simulation model development in ball-end milling. In machining, cutting force is estimated by multiplying cutting cross-section area to specific cutting forces. Specific cutting force, that is cutting parameter, is one of the important factors for cutting force prediction model and has different values according to workpiece materials. Cutting cross-section area is simply estimated in 2 dimensional cutting, but not simply estimated in 3 dimensional cutting due to complex cutting mechanics. In finishing cutting of free form surface using ball-end milling, cutting is almost performed in the ball part of the cutter and tool geometry such as tool radius, helix angle along length from tool tip are varied. As a result, cutting speed, effective helix angle and rake angle of the ball end mill are different according to length from tool tip. Study on undeformed chip thickness can be based other research, for example, cutting force prediction, tool deflection and dimensional error characteristics simulation. For undeformed chip thickness estimation, tool and chip geometry are analyzed and then the definition of chip thickness and estimation method are described. The results of analysis are compared with geometrical simulation and other method.