• 제목/요약/키워드: Cutting-Simulation

검색결과 464건 처리시간 0.028초

선삭에서 절삭 속도 제어를 통한 표면 거칠기 향상 (Improvement of Surface Roughness by the Cutting Speed Control for Turning Operation)

  • 최종환
    • 한국기계가공학회지
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    • 제7권2호
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    • pp.23-30
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    • 2008
  • As a basic machining process, turning is a widely used machining process in which a single-point cutting tool removes material from the surface of a rotating material. A common method of evaluating machining performance is to measure the surface roughness. In a turning operation, it is important to select cutting conditions for achieving high cutting performance. As a rule, cutting conditions can be classified into feed rate, depth of cut and insert radius. While cutting process even though cutting conditions are optimized, the average roughness can be deterioration due to wear of the cutting tool edge. In this study, the aim is to maintain the average roughness even though the cutting condition is irregularly changing within the predictable range due to the working environment. First, the surface roughness model influenced by cutting conditions is constructed based on the experimental results in a turning operation, Second, applying the sliding mode control theory to the turning operation model which is composed of the surface roughness model and the motor transfer function, the surface roughness is closed to the desired value. Finally, the effectiveness of this approach is demonstrated through the computer simulation.

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SPH 코드를 사용한 TBM 디스크커터의 암석 절삭에 대한 수치해석적 연구 (A numerical study on rock cutting by a TBM disc cutter using SPH code)

  • 정호영;전석원;조정우
    • 한국터널지하공간학회 논문집
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    • 제15권3호
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    • pp.345-356
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    • 2013
  • 본 연구에서는 SPH(Smoothed Particle Hydrodynamics) 코드를 사용하여 TBM에 장착되는 디스크커터에 의한 암석의 절삭과정을 모사하였다. 이를 위하여 본 연구에서는 3차원 FEM 해석 상용프로그램인 AUTODYN3D를 사용하였으며 이를 통해 국내 황등화강암을 대상으로 총 25개의 절삭조건에 대한 수치적인 절삭시험을 수행하였다. 암석과 디스크커터를 각각 라그란지안 솔버와 SPH 솔버를 사용하여 3차원 형상으로 모델링 하고 두 개의 디스크커터가 순차적으로 암석을 절삭하도록 모델링 하였다. 수치해석과 LCM시험에서 측정한 디스크커터의 작용력은 오차 10%이내의 값을 보여 대체로 일치하는 것으로 나타났고 균열의 전파양상과 암석의 파쇄양상 또한 유사한 것으로 나타났다. 또한 절삭된 최적 커터간격을 측정한 결과 LCM시험 결과와 일치하였다. 이를 통해 SPH코드를 사용한 수치해석기법의 적용성을 확인할 수 있었으나 해석시간을 단축하기 위한 Lagrange-SPH코드의 커플링에 관한 후속연구가 필요할 것으로 판단되었다.

형재 절단기 개발에 관한 연구 (A Study on Development of Channel Cutting Machine)

  • 이춘만
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 춘계학술대회논문집
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    • pp.140-143
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    • 1999
  • The major objective of the present paper is to develop a channel cutting machine and to establish an analytical technique for actual shearing process. Isothermal finite element(FE)-simulation of the shearing process are carried out using FE software DEFORM. The element-kill method has enabled the achievement of FE-simulation from the initial stage to the final stage of the shearing process. The effects of the punch-die clearance on the shearing process are investigated.

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견실한 서보적응제어기를 응용한 절삭력 추종제어 (Application of an Adaptive Robust Controller to Cutting Force Regulation)

  • 김종원
    • 대한기계학회논문집
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    • 제15권1호
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    • pp.78-89
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    • 1991
  • 본 연구에서는 ARSC를 엔드밀링 공정에 적용하여, 절삭력을 추종제어하는 실 예를 제시하고자 한다.제2장에서는 ARSC를 절삭공정에 일반적으로 적용하기 위한 구체적인 이론전개를 설명하여, 제3장에 실시간 시뮬레이션의 방법과 결과를 예시하 고,마지막으로, 제4장에 엔드밀링 절삭시험을 위한 장치의 구성 및 그 결과를 설명하 였다.

2날 엔드밀 슬롯 가공시 칩두께 모델의 개선 (Improvement of Chip Thickness Model in 2-flutes Slot End Milling)

  • 이동규;이기용;이근우;오원진;김정석
    • 한국정밀공학회지
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    • 제22권1호
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    • pp.32-38
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    • 2005
  • Generally, cutting force models use a sin function method to calculate chip thickness. In slot end milling, the error from a sin function method is much bigger than other machining because a tool rotation angle in cutting is much larger. Thus in this paper, a new method to calculate chip thickness was suggested and evaluated. In a new method, tool position data according to tool rotation are checked and stored so that it is possible correct chip thickness is calculated. Cutting force waveforms simulated from a sin function method and a new method and measured waveforms from experiments were compared and error percentages were obtained. Finally, a new method had good results for simulating cutting force in slot end milling.

향상된 절삭력 모델 기반의 NC 코드 최적화 (NC Code Optimization Based on an Improved Cutting Force Model)

  • 이한울;고정훈;조동우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 추계학술대회 논문집
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    • pp.37-42
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    • 1997
  • Off-line feed rate scheduling is an advanced methodology to automatically determine optimum feed rates for the optimization of NC code. However, the present feed rate scheduling systems have lim~tations to generate the optimized NC codes because they use the material removal rate or non-generalized cutting force model. In this paper, a feed rate scheduling system based on an improved cutting force model that can predrct cutting forces exactly in general machining was presented. Original blocks of NC code were divided to small ones with the modified feed rates to adjust the peak value of cutting forces to a constant vale. The characteristic of acceleration and deceleration for a given machrne tool was considered when off-line feed rate scheduhng was performed. Software for the NC code optimization was developed and applied to pocket machining simulation.

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선반작업에서 Ploughing Mechanism을 고려한 표면 거칠기에 관한 연구 (A Study on The Surface Roughness by Ploughing Mechanism in Turning Process)

  • 홍민성
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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    • pp.251-256
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    • 1999
  • "Ploughing" on the flank face of the tool in the metal cutting process is due to the tool in the metal cutting process is due to the finite edge radius of the tool and due to the development of flank wear. Because of the high stresses near the cutting edge, elastic-plastic deformation would be caused between the tool and the machined surface over a small area of the tool flank. The deformation would affect the roughness of the machined surface. Recently, some attempts have been made to predict the surface roughness, but elastic-plastic effect due to ploughing in the cutting process has not been considered. The research has analyzed mechanism of the ploughing of the cutting process using contact mechanics. Tool and workpiece material properties have been taken into account in the prediction of the surface roughness. The surface roughness has been simulated by the surface-shaping system. The results between experiment and simulation have been compared and analyzed. analyzed.

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4날 엔드밀 가공시 런아웃 모델링과 측정 방법 (Runout Modeling and Measurement Method in 4-flutes End Milling)

  • 이기용;이동규;이근우;박진호;김정석
    • 한국정밀공학회지
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    • 제21권3호
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    • pp.22-29
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    • 2004
  • Runout causes severe differences among cutting force waveforms due to changes of rotational radii. Thus a runout model must be included in a cutting force model to simulate cutting force accurately. In this paper, a runout modeling method and a measurement method using a dialgauge were developed, which were easy to apply. To calculate runout parameters, a computer program algorithm which obtained runout parameters from measurement values was developed. Cutting force waveforms simulated from cutting force model considering runout effect and measured from experiments had good agreements for their wave size and order.

고속 볼앤드밀링에서 공구마모를 고려한 공구의 가공경사각 선정 (Selection of Machining Inclination Angle of Tool Considering Tool Wear in High Speed Ball End Milling)

  • 고태조;정훈;김희술
    • 한국정밀공학회지
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    • 제15권9호
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    • pp.135-144
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    • 1998
  • High speed machining is a key issue in die and mold manufacturing recently. Even though this technology has great potential of high productivity. tool wear accelerated by high cutting speed to the hardened materials is other barrier. In this research, we attempted to reduce tool wear by considering tool inclination angle between tool and workpiece. The boundary lines describing machined sculptured surfaces were represented by both of cutting envelop condition and the geometric relationship of successive tool paths. Chip cross section, and cutting length could be obtained from the calculated cutting edge and the rotational engagement angle. From the simulation results, machining inclination angle of tool of $15^\circ$ was good enough from the point of tool wear and cutting force, and this value was verified through the cutting experiment of high speed ball end milling.

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고능률 가공을 위한 절삭 동력 기반의 이송 속도 최적화 (Cutting Power Based Feedrate Optimization for High-Efficient Machining)

  • 조재완;김석일
    • 대한기계학회논문집A
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    • 제29권2호
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    • pp.333-340
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    • 2005
  • Feedrate is one of the factors that have the significant effects on the productivity, qualify and tool life in the cutting mechanism as well as cutting velocity, depth of cut and width of cut. In this study, in order to realize the high-efficient machining, a new feedrate optimization method is proposed based on the concept that the optimum feedrate can be derived from the allowable cutting power since the cutting power can be predicted from the cutting parameters as feedrate, depth of cut, width of cut, chip thickness, engagement angle, rake angle, specific cutting force and so on. Tool paths are extracted from the original NC program via the reverse post-processing process and converted into the infinitesimal tool paths via the interpolation process. And the novel NC program is reconstructed by optimizing the feedrate of infinitesimal tool paths. Especially, the fast feedrate optimization is realized by using the Boolean operation based on the Goldfeather CSG rendering algorithm, and the simulation results reveal the availability of the proposed optimization method dramatically reducing the cutting time and/or the optimization time. As a result, the proposed optimization method will go far toward improving the productivity and qualify.