http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
황주호(Jooho Hwang),심종엽(Jong Youp Shim),홍성욱(Seong-Wook Hong),이득우(Deug-Woo Lee) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.3
The error motion of a machine tool spindle directly affects the surface errors of machined parts. The error motions of the spindle are not desired errors in the three linear direction motions and two rotating motions. Those are usually due to the imperfect of bearings, stiffness of spindle, assembly errors, external force or unbalance of rotors. The error motions of the spindle have been needed to be decreased to desired goal of spindle’s performance. The level of error motion is needed to be estimated during the design and assembly process of the spindle. In this paper, the estimation method for the five degree of freedom (5 D.O.F) error motions of the spindle is suggested. To estimate the error motions of the spindle, waviness of shaft and bearings, external force model was used as input data. And, the estimation models are considering geometric relationship and force equilibrium of the five degree of the freedom. To calculate error motions of the spindle, not only imperfection of the shaft, bearings, such as rolling element bearing, hydrostatic bearing, and aerostatic bearing, but also driving elements such as worm, pulley, and direct driving motor systems, were considered.
피드포워드 제어를 이용한 위상차 보정 속도리플 제어기의 설계
태원형(Won-Hyoung Tae),김정한(Jung-Han Kim),심종엽(Jong-Youp Shim),오정석(Jeong-Seok Oh),송준엽(Jun-Yeob Song) Korean Society for Precision Engineering 2014 한국정밀공학회지 Vol.31 No.8
In this paper, we propose a novel velocity ripple controller using phase compensation feedforward control. Velocity ripples result in many kinds of performance degradations in manufacturing machines, especially such as ultra-precision roll lathes. The generation of velocity ripple in constant velocity control comes from various causes, such as electrical torque ripples, mechanical worn out, inconsistent mass center, etc. Conventional researches about ripple is mainly for reducing torque ripple in actuator level, which is only one of reasons for velocity ripples, so in this study, we focus on eliminating velocity ripples in upper level controller using phase compensation feedforward controller. The proposed algorithm is composed of several modules, such as ripple extractor, phase adjuster and phase follower etc. The suggested algorithm can be easily extended, and it shows a superior performance in the experiments of ultra-precision roll lathes.
오정석(Jeong Seok Oh),송창규(Chang Kyu Song),황주호(Jooho Hwang),심종엽(Jong Youp Shim),박천홍(Chun Hong Park) Korean Society for Precision Engineering 2013 한국정밀공학회지 Vol.30 No.12
We report an ultra-precision lathe designed to machine micron-scale features on a large-area roll mold. The lathe can machine rolls up to 600 ㎜ in diameter and 2,500 ㎜ in length. All axes use hydrostatic oil bearings to exploit the high-precision, stiffness, and damping characteristics. The headstock spindle and rotary tooling table are driven by frameless direct drive motors, while coreless linear motors are used for the two linear axes. Finite element method modeling reveals that the effects of structural deformation on the machining accuracy are less than 1 ㎛. The results of thermal testing show that the maximum temperature rise at the spindle outer surface is approximately 0.5 °C. Finally, performance evaluations of the error motion, micro-positioning capability, and fine-pitch machining demonstrate that the lathe is capable of producing opticalquality surfaces with micron-scale patterns with feature sizes as small as 20 ㎛ on a large-area roll mold.
박천홍(Chun Hong Park),오정석(Jeong Seok Oh),심종엽(Jong Youp Shim),황주호(Jooho Hwang) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.7
The large surface micro machining system includes the equipments and processes for manufacturing the ultra precision micro patterned products with large surface through the mechanical machining. Recent major issue on the micro machining technology may be the development of optical parts for the back light unit of display which has the largest market. This special issue makes up with three parts; the large surface micro machining system and machine, machining process and forming process. In this paper, the state-of-the-art and core technology of large surface micro machining system is introduced with focus on the manufacturing technology for the back light unit of LCD TV. Then, some research results on the development of a roll die lathe is introduced which involves the concept of machine design, improvement of thermal characteristics in the spindle system, improvement of relative parallelism and straightness between spindle system and long stroke feed table, machining of micro pitch patterns. Finally, the direct forming process is introduced as the future work in the large surface micro machining field.