초정밀 무심연삭기 운동요소 평가

박천홍(Chun-hong Park),황주호(Jooho Hwang),조순주(Soon-Joo Cho),조창래(Chang-Rae Cho) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6

Design and performance evaluation of a spindle system which was composed of a grinding spindle and a regulating spindle for the centerless grinding of ferrule was performed in this paper. Layout and details of spindle system was designed and hydrostatic bearings for spindles were also designed. Prototype of spindle system was developed and its availabilities to machine the ferrule were discussed using the experimental results on the spindle stiffness of each spindle, loop stiffness, rotational accuracy and thermal characteristics. Loop stiffness of the spindle system was 130 N/㎛, which was enough to machine the ferrule. Rotational accuracies of each spindle were about 0.2 ㎛ at the primary speed of 2,300 rpm(grinding spindle) and 300 rpm(regulating spindle). Temperature rises at the same speed were about 4.4 ~ 4.7 ℃ in the case of grinding spindle and 1.8 ℃ in the case of regulating spindle, which were well agreed with the designed value. From these results, it was estimated that the prototype of spindle system had a enough performances for the centerless grinding machine to machine the ferrule.

공구 중량조건에 의한 주축변위 특성연구

김종관,이중기,김상복 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.4

In order to examine spindle deformation characteristics that affects the performance of dynamic cutting accuracy due to tool weight variation in a experimental spindle, thermal deformation value of operrative spindle by the axial displacement and the radial run out was measured according to the rise of spindle temperature through the laps of operation time and the change of rotational speed under the tool weight variation. A qualitative summary is as follows: 1) The results show that the tool weight affects the spindle temperature variation in a experimental spindle. 2) Radial run out and axial displacement was measured according to the rise of the spindle temperature and the performance of dynamic cutting accuracy was affected by the tool weight variation. 3) Axial displacement is 1.3 times larger than the radial run out in a experimental spindle conditions. 4) Axial displacement is continuously elongated when the tool weight is repeatly exchanged since the spindle themal deformation, however, when the same tool weight is used, the displacement is still constant.

공작기계용 40,000rpm 고속주축의 정ㆍ동적 해석과 최적설계에 관한 연구

김동현(Dong Hyeon Kim),이춘만(Choon Man Lee),최현진(Hyun Jin Choi) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.1

주축은 공작기계의 핵심요소로서 주축의 정·동적 특성은 공작물의 가공정밀도에 직접적으로 영향을 미친다. 주축의 특성은 축 크기, 베어링 간격, 내장모터의 위치 등에 의해 결정된다. 그러므로 축 크기, 베어링 간격, 모터위치의 선정은 주축 특성을 개선하는데 중요한 요소라 할 수 있다. 본 논문은 40,000rpm 고속주축의 정·동적 해석과 최적 설계에 관한 연구로, 유한요소해석과 최적화를 위한 통계분석을 하였다. 이를 위하여 반응표면법을 사용하여 목적함수와 설계변수를 최적화하였다. 최적화 대상은 주축의 고유진동수의 최대화와 변위의 최소화이다. 설계변수는 축길이, 축직경, 베어링 간격, 모터위치로 선정했다. 최적설계를 통해 도출된 설계안으로 초기모델보다 개선된 결과를 얻을 수 있었고, 본 연구의 결과를 주축 설계에 적용하면 주축의 정·동적 특성 개선에 도움이 될 것으로 기대된다. The spindle is the main component in machine tools. The static and dynamic characteristics of the spindle directly affect the machining accuracy of workpieces. The characteristics of the spindle depend on the shaft size, bearing span, built-in motor location, and so on. Therefore, the appropriate selection of these parameters is important to improve the spindle characteristics. This paper presents the analysis of the static and dynamic characteristics and optimization design of a 40,000-rpm high-speed spindle. Statistical analysis for optimization and finite element analysis were performed. This study uses the response surface method to optimize the objective function and design factors. The targets are the natural frequency and displacement. The design factors are the shaft length, shaft diameter, bearing span, and motor location. The optimized design provides better results than the initial model, and these results are expected to improve the static and dynamic characteristics of the spindle.

무심연삭기 주축계의 설계 및 성능평가

박천홍(Chun Hong Park),황주호(Joo Ho Hwang),조순주(Soon Joo Cho),조창래(Chang Rae Cho) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.11

Design and performance evaluation of a spindle system which was composed of a grinding spindle and a regulating spindle for the centerless grinding of ferrule were performed in this paper. Layout and details of spindle system were designed and hydrostatic bearings for spindles were also designed. Prototype of spindle system was developed and its availabilities to machine the ferrule were discussed using the experimental results on the spindle stiffness of each spindle, loop stiffness, rotational accuracy and thermal characteristics. Loop stiffness of the spindle system was 130 N/㎛, which was enough to machine the ferrule. Rotational accuracies of each spindle were about 0.2 urn at the primary speed of 2,300 rpm(grinding spindle) and 300 rpm (regulating spindle). Temperature rises at the same speed were about 4.4 ~ 4.7 ℃ in the case of grinding spindle and 1.8 ℃ in the case of regulating spindle, which agreed well with the designed value. From these results, it was estimated that the prototype of spindle system had enough performances for the centerless grinding machine to machine the ferrule.

초정밀 융합가공을 위한 주축이동식 자동선반의 구조해석에 관한 연구

박명규,이봉구 한국융합학회 2018 한국융합학회논문지 Vol.9 No.5

공작기계의 주축은 황삭 가공에서 부터 정삭가공에 이르는 다양한 작업들이 가능해야 하고, 정속운동 또는 회전 위치결정의 기능을 수행해야 되므로 주축설계에 고려해야 할 변수들이 많다. 주축이동식자동선반은 고정식자동선반에 비해 샤프트가 가늘고 긴 핀 들을 작업할 때 좋은 선반이다. 고정식 자동선반에 비해 외경가공의 정밀도가 매우 높다. 주축 이송 형 선반은 주로 소형 제품을 정밀가공 할 경우에 사용되므로 가공 정밀도가 높아야 한다. 최대 외경 가공 한계 치수는 Ø32, 내경가공 한계 치수는 Ø6까지 가공이 가능하게 제작되어야 한다. 본 연구에서는 주축이동식 자동선반에 사용되는 SCM440 소재의 정·동적특성을 이동식 선반에 적용하여 분석하였다. 주축의 정,동적 특성에 영향을 미치는 인자들을 고려하여 고속 화 및 고정밀도를 갖는 최적설계기술이 확보하기 위하여 수치해석을 이용하여 분석하였다. In the machine tool spindle, various tasks ranging from roughing to finishing must be possible, and the functions of constant speed movement or rotation positioning must be performed. Therefore, there are many variables to be considered in the spindle design. The Swiss Turn Type spindle automatic lathe is a good machine tool for working pins with thinner shafts than a fixed automatic lathe. The Swiss Turn Type spindle is mainly used for precision machining of small products, so the machining precision should be high. The maximum outer diameter limit shall be Ø32 and the inner diameter limit shall be Ø6. In this study, the static and dynamic characteristics of the SCM440 material used in the spindle type automatic lathe were analyzed by applying it to the Swiss turn type spindle automatic lathe. Numerical analysis was used to obtain optimal design technique with high speed and high accuracy considering the factors affecting the static and dynamic characteristics of the spindle.

경량 금속 기지 복합재와 에어 베어링을 활용한 공작기계 주축의 동적 안정성 향상 방안

배원준,김양진,김정환,조승찬,이상관 대한기계학회 2023 大韓機械學會論文集A Vol.47 No.2

An increase in the demand for high-speed and ultra-precision machining has led to the requirement of suppressing the vibration generated from a machine tool spindle. To improve the dynamic stability of a machine tool spindle by avoiding resonance, the first natural frequency of the spindle should be increased. In this study, the dynamic characteristic of a machine tool spindle was improved using the air bearing and lightweight metal matrix composite (MMC). The lightweight material was created using a liquid pressing infiltration process, and the mechanical properties of the new material were obtained. After the air bearing spindle was designed and the bearing stiffness was calculated using the design parameters, finite element analysis was performed. The superior dynamic analysis results of the MMC-applied spindle revealed that the MMC was a more suitable material than the existing material for vibration suppression of the spindle shaft. 고속 및 초정밀 가공에 대한 수요가 증가함에 따라, 산업에서 요구되는 가공 정밀도를 충족하기 위해서는 공작기계 주축에서 발생하는 진동을 억제해야 한다. 공진을 회피하여 주축의 동적 안정성을 향상시키는 방법은 주축의 1차 고유진동수를 증가시키는 것이다. 본 연구에서는 에어 베어링과 경량 금속 기지 복합재를 활용하여 공작기계 주축의 동적 안정성을 향상시켰다. 용융가압함침공정으로 경량 소재를 제작하고 기계적 물성을 획득하였다. 이후 에어 베어링 주축을 설계하고 주축 사양에 따른 베어링 강성을 계산하였으며, 이를 바탕으로 유한요소 해석을 진행하였다. 금속복합재 적용 주축의 우수한 동적 해석 결과로부터, 금속복합재가 기존 소재보다 주축 샤프트의 진동 저감에 적합한 소재임을 입증하였다.

TiC-SKH51 금속 복합재를 이용한 공작기계 주축 진동 억제에 관한 연구

배원준,김성태,김양진,이상관 한국복합재료학회 2020 Composites research Vol.33 No.5

고속 가공과 저중량 설계에 대한 수요가 증가함에 따라, 공작기계 주축의 진동 발생 가능성이 증가하고있다. 또한 초정밀 가공에서 주축의 진동은 공작물 표면 형상에 큰 영향을 끼치게 된다. 다양한 가공 공정의 가공정밀도를 향상시키기 위해, 공작기계 주축 진동 문제를 해결하여야 한다. 이 논문에서, 공작기계 주축의 진동 억제를 위해 TiC-SKH51 금속 기지 복합재가 사용되었다. TiC-SKH51 복합재의 동적 특성을 확인하기 위해 충격 망치 시험을 수행하였다. FEA의 모드 분석 결과와 충격 망치 시험 결과를 비교하여 FEA의 신뢰성을 확인한 후, 공작기계 주축 모델의 해석이 실행되었다. FEA 결과로부터 진동 발생 억제를 위해 TiC-SKH51 복합재를 적용한 공작기계 주축이 사용될 수 있음을 확인하였다. With increasing demands for high-speed machining and lightweight design of machine tools, increasing likeliness of generation of machine tool spindle vibrations has become an important issue. Spindle vibration has a significant impact on the surface finish of the workpiece in ultra-precision machining. It is necessary to resolve the machine tool spindle vibration in various machining processes to improve machining accuracy. In this paper, a TiCSKH51 metal-matrix composite was used to suppress the vibration of the machine tool spindle. To confirm the dynamic characteristic of the TiC-SKH51 composite, impact hammer tests were conducted. After verifying the reliability of a finite element analysis (FEA) by comparing the results of the impact hammer test with the modal analysis using FEA, the analysis of the machine tool spindle model was performed. The FEA results show that the TiC-SKH51 composite applied machine tool spindle can be utilized to suppress the vibration generation.

고속모터주축의 유량과 점도에 따른 열특성 해석

최대봉(Dae-Bong Choi),유기한(Ki-Han Yu),김수태(Soo-Tae Kim) 한국기계가공학회 2008 한국기계가공학회 춘추계학술대회 논문집 Vol.2008 No.-

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 recently. The important problem in this spindle is to reduce and minimize the thermal effect by motor and bearing. This paper presents the thermal characteristics analysis of a high speed motor spindle system consisted of angular constant ball bearings and built-in motor with oil-jet lubrication. The analysis of thermal characteristic of spindle is performed according to the oil-jet lubrication by using finite element method. This result can be applied to the design and manufacture of the high speed spindle.

오일-제트 윤활 방식의 모터 분리형 초고속 주축계의 열 특성 해석

김석일,김기태 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.1

This paper presents the thermal characteristics analysis of a high-speed motor-separated spindle system consisted of angular contact ball bearings and built-in motor with oil-jet lubrication. The spindle system is composed of the main spindle and sub-spindle which are mechanically connected by a flexible coupling. The spindles are supported by two front and rear bearings, and the built-in motor is located between the front and rear bearings of the sub-spindle. The thermal analysis model of spindle system is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on temperature distribution and heat flow under the various testing conditions related to material of bearing ball, spindle speed and coolant temperature.

금속복합재 TiC-SUS431을 사용한 공작기계 주축 열변형 억제에 대한 연구

서지원(Ji Won Seo),배원준(Won Jun Bae),김성태(Sung Tae Kim),김양진(Yang Jin Kim),이상관(Sang Kwan Lee) 대한기계학회 2020 大韓機械學會論文集A Vol.44 No.7

공작기계에서 주축의 열변형은 가공 오차의 주요 원인이다. 이러한 열적 오차를 억제하는 근본적인 해결책은 기존의 주축 재료를 뛰어난 기계적 성질을 갖는 재료로 대체하는 것이다. 이에 적합한 금속 복합재 TiC-SUS431은 우수한 가공성과 내마모성, 내산화성을 갖고 있으며 본문에서 균일한 열확산율과 낮은 열팽창 계수를 확인하였다. 유한요소 해석을 이용하여 TiC-SUS431과 SUS431, 기존 주축 재료인 GC300을 각각 사용한 주축에서 열변형을 비교한 결과, TiC-SUS431을 사용한 주축에서 변형이 가장 작은 것을 확인하였다. 이를 통해 TiC-SUS431의 열변형 억제 능력을 확인하여 주축의 재료로서 적용 가능성을 제시하였다. The thermal deformation of a spindle is one of the sources of errors in machine tools. A fundamental solution to this thermal error problem involves replacing the conventional material used in producing spindles with an advanced material. TiC-SUS431 is a metal composite that exhibits satisfactory machinability, wear resistance, and oxidation resistance. The experimental tests conducted in this study confirmed the excellent thermal properties of the TiCSUS431 composite, including a uniform thermal diffusivity and low thermal expansion coefficient. We conducted finite element analysis (FEA) of a spindle using TiC-SUS431, SUS431, and GC300 based on the variation of the generated heat and time. The FEA results indicated that the thermal deformation of a spindle fabricated from TiC-SUS431 is minimal when compared with those of SUS431 and GC300. This suggests the potential of using TiC-SUS431 composite as an alternative material for manufacturing spindles due to its low thermal expansion coefficient. Hence, this in turn can decrease the thermal strain in a spindle.