• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.4
• /
• pp.134-140
• /
• 2016

Main Spindle System has effect on performance of machine tools and working quality as well as is required of high reliability. Especially, it takes great importance in producing automobiles which includes a large number of working processes. However, main spindle unit in Machine tools are often cases where damage occurs do not meet the design life due to driving in harsh environments. This is when excessive maintenance and repair of machine tools or for damage stability has resulted in huge economic losses. Therefore, this studying propose a method of accelerated life test for diagnosing and prognosis the state of life assessment main spindle system. Time status monitoring of diagnostic data - through the analysis of the frequency band signals were carried out inside the main spindle bearing condition monitoring and fault diagnosis.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.32-37
• /
• 2000

In a high speed spindle system, it is very important to monitor the operation of the spindle to prevent catastrophic damage to the system. Widely used sensors for monitoring are eddy-current and capacitive types. These sensors provide high accuracy of monitoring, but their steep prices lead to expensive high speed spindle system. The main god of our research is to develop technology to produce high speed spindle system utilizing magnetic bearings. As active magnetic bearings require position sensors for feedback control, a noncontact position sensor is bang developed as a part of this main goal. Once developed, it will contribute to affordable high speed spindle system. In this paper, we report the selection process of the sensor types and the experimental results with driving circuits.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.4
• /
• pp.2350-2355
• /
• 2015

A tool was developed in this research for automation of one-dimensional finite element analysis (1D FEA) for design of a machine tool spindle system composed mainly of a shaft and bearings. As it is based on object-oriented programing, it uses the objects of a CAD system. It requires minimum data to be input to define the spindle system such as shaft cross-sections and bearing stiffness. Then, it automatically generates the geometric model based on the data and then, converts it into the FE model of 1D beams and springs. The graphic user interfaces developed allow a user to interact with the tool. This tool can be applied to identification of a near optimal design of the spindle system in minimum time and efforts by automating the FEA process with numerous design changes.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.351-356
• /
• 1993

최근의 프로세스 공업화에 있어서 생산Line의 장치나 기계류는 점차 대형화, 고속화,연속화,복잡화되고 있다. 또한, 기계가공공업,자동차공업,기계,전자부품의 가공조립등의 생산설비는 각설비가 고도로 자동화되고 있는 실정으로 공장 전체의 유기체적인 제어 및 감독을 필요로 하고 있다. 마찬가지로 기계부품제작산업도 CNC.FMS등으로 점차 조작화,자동화됨에 따라 공작기계 장치나 기계류등의 이상이나 고장으로 생산 및 품질에 미치는 영향도 종래와 비교할 수 없을 정도로 중요시 되고 있는 실정이다, 이와같이 설비의 안전성을 도모하고 고신뢰도를 부여하기위해서는 기계설비의 이상 및 고장진단이 필수적이며, 공장 자동화와 함께 공작기계자체의 고장 및 이상진단을 실시하고, 검출된 신호의 크기등으로 고장상태를 판정해야만 한다. 공작기계에서 동적인 회전시스템을 이루는 주축용베어링의 손상은 제작하고자 하는 제품의 정밀도 표면거칠기등의 저하 뿐만아니라 시스템 전체의 기능까지도 떨어뜨리는 요인이 될수 있으므로 베어링 상태를 진단하여 송상유무를 판단하는것은 필수적이라 생각된다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1992.04a
• /
• pp.216-222
• /
• 1992

현재의 가공 시스템에 있어서 가공 작업자체는 NC 공작기계, 머시닝 센터등에의해 자동적으로이루어 지고있으나, 작업 상태에 대한 감시 및 공구교환 시기의 결정은 주로 숙련된 작업자에 의해이루어 지고 있으므로완전 자동화, 무 인화에 큰장애가 되고 있다. 특히 공구 파손 및 공구 마멸에 대한 감시는 공구 교환 시점의 자동결정 뿐 아니라 가공 시스템의 무인 운전을 위해서 필수적인 것으로, 기계 정지 시간(down time)을 줄일 수 있고, 제품의 정밀도를 높일 수 있다. 본 연구에서는 이를 위한 기초 연구로, 가공상태를 나타내는 감시신호로 AC 주축 모터 전류와 주축대진동 신호 를 선정하여 엔드밀 공구와 드릴 공구를 이용한 작업에서의 공구 상태변화에 따른 감시신호의 성능을 조사하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.2
• /
• pp.203-212
• /
• 2002

Active magnetic hearings allow much high surface speed than conventional ball bearings and therefore greatly suitable for high speed cutting. This paper describes a design and test of an active magnetic bearing system with 16-pole radial magnets. The spindle is originally designed for a CNC lathe and driven by outer motor with 5.5 kW power and maximum speed 10,000 rpm. Considering static load condition and geometric restrictions, radial magnet is designed 16-pole type for smaller outer diameter of the spindle system. Dynamic system characteristics such as natural frequency, critical speed, stiffness, damping and system stabilities are simulated with a rigid rotor model including direct feedback controller. The designed spindle system is realized with digital PIDD controller to compensate phase lag of PWM amplifier and magnet coils. With levitation and step response experiment the control system characteristics are tested, and the spindle is rotated up to 10,000 rpm stab1y.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.5
• /
• pp.20-25
• /
• 2011

In this paper, we reviewed the spindle system's motor and bearing and its mode safety for optimal design of a high speed spindle system that exceeds DmN value of 1,500,000. We could verify that it has a separation margin during critical speed by performing critical speed analysis. Also, we have selected an optimal sensoring installation location and actually manufactured & installed the sensor by identifying the stress concentration position in the axial load through finite element analysis to install the built-in piezo electric type load sensor to the spindle housing that can measure and monitor the machining load during high speed rotation of the spindle. Reproducibility is also verified by calibrating the error through the sensor's sensitivity adjustment after comparing the output between the plate dynamoneters and the load sensor to confirm the reproducibility of the load sensor.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.3 s.96
• /
• pp.297-305
• /
• 2005

A high-speed spindle can be very sensitive to rotating mass unbalance which has harmful effect on many machine tools. Therefore, the balancing procedure to reducevibration in rotating system is certainly needed for all high-speed spindles. An active balancing program using influence coefficient method and an active balancing device of an electro-magnetic type have been applied to the developed high-speed spindle system in this study. A reliable gain-scheduling control using influence coefficients of the reference model although system characteristics are changed is applied. The stability of reference influence coefficients is verified by frequency response functions. The active balancing experiment for the developed high-speed spindle during operation is well performed with an active balancing program and device. As a result, controlled unbalance responses are below the vibration limit at all rotating speed ranges with critical speed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.10a
• /
• pp.64-69
• /
• 1993

최근의 생산시스템은 FMS,FMC와 같은 고도로 자동화된 무인시스템으로 운용되고 있으며, 생산성 향상을 위한 무인운전의 필요성이 증대되고 있으나, 숙련된 작업자를 대신하여 작업상태를 감시하는 신뢰성 있는 감시 시스템의 부족으로 인해 곤란을 겪고 있다.따라서 작업자를 대신할수 있는 신뢰성있는 감시 시스템의 개발을 필요로 한다. 특히 공구파손,공구마멸과 같은 공구손상은 공작물 및 기계에 치명적 손상을 초래하고, 기계정지시간을 증가시키므로 공구파손 검출과 공구마멸의 실시간 센싱은 가공 프로세스의 자동화와 신뢰성을 증가시키는데 가장 중요한 역활을 수행한다. 본 연구에서는 드릴가공시 검출한 주축 및 Z축 모터전류를 기초로 하여 드릴마멸을 추정하는 모델을 개발하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.65-68
• /
• 2002

In a high speed spindle system, it is very important to monitor the state of rotating rotor. Particularly in active control spindle system, the position sensor must provide feedback to the control system on the exact position of the rotor. In order to monitor the state of a high speed spindle exactly, High accuracy and wide frequency bandwidth of sensors are important. This paper describes the factors which has an effect on performances of inductive position sensor. We also report the experimental results that characterize the performances of the inductive position sensor.