• Title/Summary/Keyword: High speed spindle

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Effects of a drawbar and a rotor in dynamic characteristics of a high-speed spindle (드로우바와 로터가 고속주축계의 동적 특성에 미치는 영향)

  • Chung Won-Jee;Lee Choon-Man;Lee Jung-Hwan;Lim Jeong-Suk
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.3 s.180
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    • pp.139-146
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    • 2006
  • The spindle system with a built-in motor can be used to simplify the structure of machine tools, to improve the machining flexibility of machine tools, and to perform the high speed machining. For more quantitative analysis of a built-in motor's dynamic characteristics, that of tile mass and stillness effects are considered. And the drawbar in the spindle can be in various condition according to supporting stiffness between drawbar and shaft. Therefore, in this paper following items are performed and analyzed : 1. Modal characteristics of the spindle. 2. Analysis of rotor's mass and stiffness effects. 3. Modal characteristics of the spindle including drawbar, rotor and tool. The results show enough stiff supports must be provided between shaft and drawbar to prevent occurring drawbar vibration lower than the natural frequency of 1st bending mode of the spindle, and considering the mass and stiffness of built-in motor's rotor is important thing to derive more accurate results.

Design of High Speed Spindles Active Monitoring and Control Algorithm (고속 주축의 상태모니터링 및 제어 알고리즘 설계)

  • Choi, Hyun-Jin;Park, Chul-Woo;Bae, Jung-Sub;Ahn, Jeong-Hun;Choi, Seong-Dae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.5
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    • pp.13-19
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    • 2011
  • In this paper, the active monitoring and control system is developed. This system can monitor the status of high the speed spindle in real time during its processing, and can analyze its influence of dimensional accuracy and processing if any, and can control the machining condition to realize the machining system equipped with active monitoring and self-diagnostic features. Machining experiment was performed on 3 materials Al, Brass and S45C in order to derive the relation between active monitoring and control algorithm by the machining load. In addition, we measured surface roughness of processing specimen along with the data change of spindle rotating speed and conveying speed according to variation of machining load. Based on these experiments, we derived relations for each material that can be applied to the control algorithm to allow self control of the rotating speed and conveying speed according to the machining load.

A study on the heat generation into air film as rotating of high speed journal in the air journal bearing (공기저어널 베어링에서 저어널의 고속회전시 공기유막내의 열발생에 관한 연구)

  • 이종열;성승학;이득우;박보선;김태영
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.82-86
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    • 2002
  • The thermal characteristics of high-speed air spindle system with built-in motor are studied. Experiment and finite difference method analysis obtain temperature rise and temperature distribution of housing. For the analysis, air fluid film model is built and temperature rise and distribution in thermal steady state are computed for each rotational speed. Generally, it is said that the heat generation of air bearing is negligible. But the heat generation in air film by heat dissipation can not be negligible especially into high-speed region of the journal. In case that the heat generation of air spindle system is high, natural frequency of the spindle system becomes lower when the thermal state is in steady-state and it means the changes of air bearing stiffness due to the change of bearing clearance. It is shown that the temperature rise of air spindle system causes thermal expansion and induces the variation of bearing clearance. In consequence the stiffness of air bearing becomes smaller.

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An Elastic Deformation Model of High-speed Spindle Units

  • Zverev Igor Aexeevich;Eun In-Ung;Hwang Young-Kug;Chung Won-Jee;Lee Choon-Man
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.3
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    • pp.39-46
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    • 2006
  • This paper presents an elastic deformation model of a spindle unit (S/U), which takes into account the non-linear properties of high-speed ball bearings (particularly the effect of high rotational speed). For this, a software for the estimation of the S/U elastic deformation properties was developed and intended for use by S/U designers. A computer aided analysis of the model using the developed software was carried out and experiments showed the significant effect of rotational speed, cutting load and bearing axial preload, and showed some new phenomena, from which the criteria for the choice of bearing axial preload is given.

A Theoretical Investigation for Improving Dynamic Characteristics of Inductive position sensor (유도형 변위 센서의 동적 특성 향상을 위한 이론적 고찰)

  • 신우철;홍준희;이동주
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.149-154
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    • 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 observes the factors which has an effect on dynamic performances of inductive position sensor.

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Study of Cutting Characteristics in High Speed Synchronized Tapping (고속 동기 탭핑에서의 절삭 특성에 관한 연구)

  • 정용수;이돈진;김선호;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.304-307
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    • 2002
  • High speed machining was accomplished. through the technological advances which covers the whole field of mechanical industry. But tapping have many troubles because of its complicate cutting mechanism, for example. tool damage, chip elimination and synchronization between spindle rotation and feed motion. But High speed tapping is so important that it marches in step with the flow of the times and make improvement in the productivity. In this paper we analyze mechanism of high speed synchronized tapping with the signal of tapping torque and spindle speed obtained through the newly developed high speed tapping machine(NTT-30B). We made an experiment with this machine on condition of various speed from 1000rpm to 10000rpm. As one complete thread is performed through the whole chamfer cutting, cutting torque increases highly in chamfer cutting, but smoothly in full thread cutting functioning of the threads guide. And the size of cutting torque according to spindle speed(rpm) was not enough of a difference to be conspicuous.

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Design of High Speed Composite Air Spindle System (초고속 복합재료 공기정압 주축의 설계)

  • 장승환;이대길;한흥삼
    • Composites Research
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    • v.14 no.1
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    • pp.47-56
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    • 2001
  • In order to enhance high speed stability the composite air spindle system composed of a high modulus carbon fiber composite shaft, powder contained epoxy composite squirrel cage rotor and aluminum tool holder was designed and manufactured. For the optimal design of the composite air spindle system, the stacking sequence and thickness of the composite shaft were selected by considering the fundamental natural frequency and deformation of the system. The analysis gave results that the composite air spindle system had 36% higher natural frequency relative to a conventional air spindle system. The dynamic characteristics of the composite spindle system were compared with those of a conventional steel air spindle system. From the calculated and test results, it was concluded that the composite shaft and the power contained composite rotor were able to enhance the dynamic characteristics of the spindle system effectively due to the low inertia and high speific stiffness of the composite materials.

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Design of High Precision Spindle System for ferrule Grinding Machine (페룰 가공용 고정밀 주축시스템 개선설계)

  • Pyoun, Y.S.;Park, J.H.;Lee, K.B.;Yokoi, Y.;Yeo, J.W.;Jeong, I.Y.;Ahn, K.J.;Kwak, C.H.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1003-1007
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    • 2003
  • In order to improve the international competitiveness of ferrule industry, the core technology of the second stage for ferrule grinding system is under developing. A high speed (10,000RPM) and high precision spindle system(Radial Runout 0.2 micrometer) bearing more cutting torque and force is designed considering the limitation of cost and size, the effect of heat, and various work-piece materials. A CAE software for machine elements and general machine system is used for preliminary evaluation and selection of design parameters. A dedicated program for the analysis of spindle system is used for final evaluation and selection of design parameter. The process how to evaluate and select using such tools are presented.

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Optimum Bar-feeder Support Positions of a Miniature High Speed Spindle System by Genetic Algorithm (유전 알고리듬을 이용한 소형 고속스핀들 시스템의 바-피더 지지부의 위치 최적선정)

  • Lee, Jae-Hoon;Kim, Mu-Su;Park, Seong-Hun;Kang, Jae-Keun;Lee, Shi-Bok
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.11
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    • pp.99-107
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    • 2009
  • Since a long work piece influences the natural frequency of the entire system with a miniature high speed spindle, a bar-feeder is used for a long work piece to improve the vibration characteristics of a spindle system. Therefore, it is very important to design optimally support positions between a bar-feeder and a long work piece for a miniature high speed spindle system. The goal of the current paper is to present an optimization method for the design of support positions between a bar-feeder and a long work piece. This optimization method is effectively composed of the method of design of experiment (DOE), the artificial neural network (ANN) and the genetic algorithm (GA). First, finite element models which include a high speed spindle, a long work piece and the support conditions of a bar-feeder were generated from the orthogonal array of the DOE method, and then the results of natural vibration analysis using FEM were provided for the learning inputs of the neural network. Finally, the design of bar-feeder support positions was optimized by the genetic algorithm method using the neural network approximations.