소형 태핑센터 주축의 열특성 및 주파수 분석

최대봉(Dae-Bong Choi),김수태(Soo-Tae Kim),노승국(Seung-Kook Ro),조현택(Hyun-Taek Cho) 한국기계가공학회 2012 한국기계가공학회지 Vol.11 No.2

High speed machining is the core technology that influences the performance of machine tools, and the high speed motor spindle is widely used for the high speed machine tools. The important problem in high speed spindle is to minimize the thermal effect by motor and bearing and frequency effect. This paper presents the thermal characteristic analysis and frequency experiment for a high speed spindle considering the flow rate of cooling oil. A high speed spindle is composed of angular contact ceramic ball bearings, high speed built-in motor, oil cooling jacket and so on. The thermal analyses of high speed spindle need to minimize the thermal effect and maximize the cooling effect and they are carried out under the various cooling conditions. Heat generations of the bearing and the high speed motor are estimated from the theoretical and experimental data. To find out the characteristic of vibration, the high speed spindle is excited in operational range. This result can be applied to the design and manufacture of a high speed tapping spindle.

고속 회전시 베어링 강성강하를 고려한 주축 유니트의 최적화

이찬홍(Chan Hong Lee) 한국생산제조학회 2010 한국생산제조학회지 Vol.19 No.6

Radial stiffness of angular contact ball bearings are decreased remarkably at high speed revolution, because the inner and outer ball contact angle with races are changed under the ball centrifugal forces at high speed. In the past, the optimizations of spindle units were done under the assumption of unchanged bearing stiffness for the whole speed range. But the bearing stiffness is changed and the dimension of optimum spindle is also changed with speed. In the design phase, only one model of many optimum spindle models with speed should be selected. As optimization criterion, the area of transfer function at spindle nose is proposed to estimate simply and accurately improvement of dynamic characteristics in spindle units. Finally, according to many analyses of diverse spindle models with decreased bearing stiffness, the spindle with shorter bearing span is better than longer bearing span from the viewpoint of dynamic characteristics.

CNC 공작기계 장착형 고속스핀들을 이용한 고속가공 실용화 기술

이용철(Yong-Chul Lee),곽태수(Tae-Soo Kwak),김경년(Gyung-Nyun Kim),이종열(Jong-Ryul Lee) 한국기계가공학회 2012 한국기계가공학회지 Vol.11 No.2

A newly developed attachment type high-speed spindle can be easily attached to the conventional CNC machining center to allow high-speed machining with low investment costs. This study has focused on the application of a conventional CNC machining center equipped with an attachment type high-speed spindle. A specimen of plastic mold material has been machined to compare the cutting effectiveness of the high-speed machining center and the conventional machining center with the attachment type high-speed spindle respectively. The rotational accuracy of the spindles are measured by a transmission optic measurement system and the surface roughness of the workpiece in accordance with revolution speed(rpm) of the spindle are investigated respectively. As the experimental results, it was shown that the surface roughness of the machined workpiece was 3.42㎛Rmax, 0.46㎛Ra in the case of attachment type spindle and 1.81 ㎛Rmax, 0.275㎛Ra in the case of the high-speed machining center. Moreover, the mean rotational accuracy was 7.57㎛ in the case of the attachment type spindle and 7.39㎛ in the case of the high-speed machining center.

Spindle Speed Optimization of a Ring Spinning Machine for Better Surface Irregularity and Hairiness of Yarn and Fabric

정성훈,Sahito, Iftikhar Ali,Arbab, Alvira Ayoub,Jeong, Sung Hoon 한국섬유공학회 2015 한국섬유공학회지 Vol.52 No.1

Producing yarn from natural fibers without creating irregularities in structure or having fibers protruding from the surface, remains the goal of spinners. This is a problem, as structural irregularities such as hairiness affect subsequent fabric manufacturing processes and the aesthetics of the final fabric. This work therefore focused on investigating the effects of varying the spindle speed of a ring spinning frame on the structure of yarn (i.e., its surface regularity and hairiness), its strength and the surface pilling of fabric made from such yarn with a view to optimizing the spindle speed. For this, yarns with counts of 20, 25, and 30 tex were produced at six different spindle speeds ranging from 11,000 to 21,000 rpm with an interval of 2,000 rpm. All other parameters were kept constant, including the draft for a particular count, the type and weight of the traveler, and the diameter of the ring. The results obtained revealed that as the spindle speed was increased to 17,000 rpm, the yarn structure became more regular and less hairy, thereby becoming stronger. Beyond 17,000 rpm, however, both the regularity and strength decreased, with the hairiness continuing to increase with increasing spindle speed. Consequently, the surface pilling of the fabric was found to be optimized when made from yarns produced at a spindle speed of 17,000 rpm.

고속주축의 냉각조건과 후반부 냉각 유무에 따른 열특성 연구

최대봉(Dae-Bong Choi),김수태(Soo-Tae Kim),이석준(Seog-Jun Lee),김창용(Chang-Yong Kim) 한국기계가공학회 2012 한국기계가공학회지 Vol.11 No.1

The important problem in high speed spindle is to reduce and minimize the thermal effect by motor and bearing. This paper presents the thermal characteristic analysis for a high speed spindle with and without cooling at the rear part, considering the viscosity and the flow rate of cooling oil. A high speed spindle is composed of angular contact ceramic ball bearings, high speed built-in motor, oil jacket cooling and so on. The thermal analyses of high speed spindle need to minimize the thermal effect and maximize the cooling effect and they are carried out under the various cooling conditions. Heat generations of the bearing and the high speed motor are estimated from the theoretical and experimental data. This result can be applied to the design and manufacture of a high speed motor spindle.

소형-고속 스핀들의 반경방향 오차분석 방법

이응삼(E. S. Lee),이재하(J. H. Lee),양승한(S. H. Yang) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월

In this paper, an efficient method is proposed to analyze the radial error of a miniaturized-high speed spindle system. Initially, a device is constructed for measuring the radial error motion using capacitance sensors. The capacitance sensors are placed perpendicular to the axis of the shaft and at 90° to each other. The spindle is rotated at high speed and the profile of the spindle is recorded. An algorithm is developed for analyzing the spindle data and determining the radial error of spindle. The present algorithm uses homogeneous transform matrix (HTM) method and iterative process for determining the radial error. The analysis procedure is performed for different speeds of the spindle. The data obtained from the present system and the results of evaluation are also presented in this paper. It is observed that this method is effective in determining and analyzing the spindle errors for high speed miniaturized spindle.

실험계획법을 이용한 주축 형상 설계에 관한 기초연구

신재호,이춘만 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in vibration of spindle This paper concerns the improvement of spindle design using design of experiments. Finite element analysis is performed by using a commercial code ARMD and CATIA V5. From the results, it has been shown that the modification of spindle design with natural frequency and spindle weight.

절삭저항을 고려한 툴 인터페이스부의 정강성 분석

신재호(J. H. Shin),이춘만(C. M. Lee),황영국(Y. K. Hwang) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.3

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in tooling system of high speed spindle. This paper concerns the static stiffness in the main spindle interface according to variation of clamping force, rotational speed and tool holder shank. Finite element analysis is performed by using a commercial code ANSYS workbench. From the results, it has been shown that the geometry of tool holder shank is mostly influence on the variation of the static stiffness in the main spindle interface.

재구성 가능형 공작기계의 주축 시스템 설계

장성현(Sung-Hyun Jang),정용민(Yong-Min Jung),황현영(Hyun-Young Hwang),최영휴(Young-Hyu Choi),박종권(Jong-Kweon Park) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.5

During a decade, there are many researches on microfactory which is the miniature, flexible, and efficient manufacturing system for the micro/meso scale machining device. Moreover many micro machine tool has developed in Japan, U.S., Europe, and Korea. Already we developed a 3-axis micro milling machine with 300×200×320 ㎜³ machine size for microfactory. In this study, we introduce the design of a high speed spindle system with air bearings for our micro milling machine. Desired operation speed range of the spindle system is 100,000 ~ 150,000 rpm. In design step, we have consideration for minimum critical speed, compliance, and weight construction of the spindle system. The shaft length, the shaft outer diameter, bearing positions and bearing stiffness were set as the design values. After the final design of spindle model, we carried out dynamic analysis a spindle system for a micro milling machine by using ADROS, which is our own developed S/W for dynamic design analysis of rotor systems. As the result, we designed a spindle system having the critical speed above the operating speed.

원통형 주축 변위 센서를 이용한 고속 밀링 가공 상태 감시

김일해(Il Hae Kim),장동영(Dong Young Jang) 한국생산제조학회 2007 한국생산제조학회지 Vol.16 No.5

A new cutting force estimating approach and machining state monitoring examples are presented which uses a cylindrical displacement sensor built into the spindle. To identify the tool-spindle system dynamics with frequency up to 2 kHz, a home-built electro-magnetic exciter is used. The result is used to build an algorithm to extract the dynamic cutting force signal from the spindle error motion; because the built-in spindle sensor signal contains both spindle-tool dynamics and tool-workpiece interactions. This sensor is very sensitive and can measure broadband signal without affecting the system dynamics. The main characteristic is that it is designed so that the measurement is irrelevant to the geometric errors by covering the entire circumferential area between the target and sensor. It is also very simple to be installed. Usually the spindle front cover part is copied and replaced with a new one with this sensor added. It gives valuable information about the operating condition of the spindle at any time. It can be used to monitor cutting force and chatter vibration, to predict roughness and to compensate the form error by overriding spindle speed or feed rate. This approach is particularly useful in monitoring a high speed machining process.