• 한국공작기계학회논문집
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• 제17권1호
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• pp.132-136
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• 2008

Axis of rotation error on rotary system are significant; such as the spindle radial error motion of a aligner, wire bonder and inspector machine which results in the poor state of manufactured goods. In this paper, the simple stage which consists of one PZT actuator and rotary encoder, is analyzed and measured by high resolution capacitance type displacement sensor. As the result of experiment, the paper discusses several issues that must be considered when designing rotary stage driven by PZT.

• 한국정밀공학회지
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• 제32권2호
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• pp.135-140
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• 2015

It is an important thing for a designer to simulate and predict the performance of a spindle and a rotary table. In addition to the general performance such as static stiffness, the error motion performance information is beneficial to the designer in many cases. However for an aerostatic bearing the fluid film physical status should be calculated in order to simulate those performances and the calculation time is another obstacle for a simple performance simulation. In this paper the investigation on experiment and simulation is performed in order to find a more effective simulation method for the rotational error motion.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.449-453
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• 2000

In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. This paper models of the thermal errors for error analysis and develops on-the-machine measurement system by which the volumetric error are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to analyze the thermal characteristics under several operating conditions, experiments performed with the touch probe unit and five gap sensors on the vertical and horizontal machining centers.

• 전기전자학회논문지
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• 제23권1호
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• pp.22-28
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• 2019

본 연구는 차량용 보링 생산 공정에서 기계적인 에러를 체크하기 위한 품질 체크용 모니터링 시스템을 개발한다. 기계적인 에러는 이상적인 절단경로와 비교하여 실제 절단경로의 공간위치 차이에서 나타난다. 제조공정 제품의 오차를 모니터하기 위해 제품의 인지왜곡, 죄임 에러, 기계공구의 회전과 운동에러의 반경회전과 같이 보링 품질에 영향을 미치는 다수 요소들을 설명한다. 생산품질을 입증하기 위해 IT 융합에 기반한 공정 에러율을 분석하고 분석 데이터를 메모리에 저장하는 품질체크 방법을 제안한다. 따라서 불량 생산 제품을 감지함으로써, 생산 코스트와 베어링의 손실을 줄일 수 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.369-374
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• 2002

This paper presents theoretical analysis of the NRRO(non-repeatable run-out) for a ball bearing with geometric imperfection. The 3DOF dynamic analysis of a ball bearing using the Newton-Raphson method is performed to calculate the displacement of shaft center. Frequency and magnitude characteristics of radial and axial vibrations are investigated. The ball form errors of the ball, the inner race, and the outer race in a HDD spindle ball bearing are precisely measured. NRRO of a ball bearing is analyzed by using the measured waviness data. It is concluded that dominant components of radial vibrations are ${\Large}f_c\;and\;2{\Larg}f_b{\pm}{\Large}f_c$, and dominant component of axial vibrations is $2{\Large}f_b$. These are generated by the size error and the second waviness of the balls.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.229-232
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• 1997

In this paper, the case study of reducing rotational errors is done for a grinding spindle with an active magnetic bearing system. The rotational errors acting on the magnetic bearing spindle are due to mass unbalance of rotor, runout, grinding excitation and unmodeled nonlinear dynamics of electromagnets. For the most case, the electrical runout of sensor target is big even in well-finished surface; this runout can cause a rotation error amplified by feedback control system. The adaptive feedforward method based on LMS algorithm is discussed to compensate this kind of runout effects, and investigated its effectiveness by numerical simulation and experimental analysis. The rotor orbit size in both bearings is reduced about to 5 pin due to lX rejection by feedforward control up to 50,000 rpm.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.309-314
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• 2001

The balance of high speed spindle system with high precision rotation like grinding machine is very important. Traditionally, we use trial and error method to balance the spindle. It takes much time. So we are developing the automatic balancing equipment being used in the grinding machine. The balancing head we develop is wireless. It will be used high-speed grinding machine. We use influence coefficient method to control the automatic balancer. Experiments are based on automatic and manual balancing. We perform test of the vibration filter. It helps to remove noise. The filter and experiments with automatic balancing controller show that automatic balancing control can be successfully achieved with the quick response and good stability characteristics.

• 한국정밀공학회지
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• 제20권9호
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• pp.40-46
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• 2003

Synchronizing errors between the spindle motor and the z-axis motor directly influences the cutting characteristics and the thread quality in tapping, because the tapping process is accomplished by synchronizing the movement of the z-axis with the revolutionary spindle motion. Generally synchronizing errors are decided by tile parameters of the servo system and commanded velocity. The excessive synchronizing errors which are induced by the parameter mismatch and high cutting velocity can cause tap breakage due to the abrupt increase of cutting torque or damage the thread accuracy by overcutting the already cut threads. In this paper, the influences of the synchronizing errors on the tapping characteristics in the ultra high-speed tapping will be described and a minimum level of synchronizing errors necessary to maintain the quality of the cut thread will be presented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.605-608
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• 1997

In this paper, the case study of reducing rotational errors is done for a grinding spindle with an active magnetic bearing system. The rotational errors acting on the magnetic bearing spindle are due to mass unbalance of rotor, runout, grinding excitation and ed nonlinear dynamics of electromagnets. For the most case, the electrical runout of sensor target is big even in well-finished surface; this runout can cause a rotation error amplified by feedback control system. The adaptive feedforward method based on LMS algorithm is discussed to compensate this kind of runout effects, and investigated its effectiveness by numerical simulation and experimental analysis. The rotor orbit size in both bearings is reduced about to 5 pin due to lX rejection by feedforward control up to 50,000 rpm.

• 한국생산제조학회지
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• 제9권3호
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• pp.96-102
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• 2000

High speed machining aims to raise the productivity and efficiency by making more precise and higher value-added products than any other machining method by means of the high speediness of spindle and feed drive system. The purpose of this study is to investigate the effects of the run-out of endmill on the dimension precision of workpiece and to obtain the fundamental data on high speed machining which is available by machining the side of Al-alloy with solid carbide endmills in high speed machining center and by measuring dimensions and surface roughness. From the results of experimentation following are obtained ; if spindle speed is ultra high in conditions that radial depth of cut and feed per tooth are very small highly precise and accurate products are to be made efficiently with high feed rate. and so we can raise productivity.