• 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.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.65-70
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• 2002

The rotational performance off machine tool spindle has a direct influence upon the surface finish of the finished workpiece. This running accuracy of the spindle is improved by increasing preload on the bearings, while it results in higher temperature rise and larger thermal deformation. Therefore, finding the optimal preload condition for high speed spindle is very important factors in spindle motion. in spindle motion. In this study, the effect of the preload on the roundness accuracy has been examined at the different cutting conditions. Experiments were carried out to investigate the effects of the bearing preload on the running accuracy of high speed spindle which was supported by two angular contact bearings.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.227-230
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• 1999

In this paper, the machining characteristics of high speed ball end milling affected by the rotational error of high speed spindle using air bearing are investigated. The error motions of a spindle have generally influenced on the surface roughness, the form accuracy, the tool life, etc. in end milling. Experiments are carried out over a wide range of rotational speeds(10,000-50,000rpm). The rotational errors of the spindle are measured by the gap sensor mounted on the spindle shaft at various cutting speeds. The relations between the surface roughness and the spindle error motion are presented. Results show that the rotational accuracy of the spindle directly affects the surface roughness of the machined surface.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.355-360
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• 2000

Recently, to be satisfied the consumer's demand the life cycle and the lead time of product is to be shorted. So it is important to reduce the time and cost in manufacturing prototypal mold. These days, in order to reduce the lead time and cost high speed machining is highlighted. In the paper, using the high speed machining and aluminum-7075, the fundamental experiment is implemented in the change of cutting force, machining time, surface characteristic according to the tool path. And then the prototypal mold of the automatic knob is machined.

• 청정기술
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• 제12권3호
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• pp.182-189
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• 2006

본 연구에서는 생산성 향상을 위하여 적용 분야가 점차로 확대되고 있는 고속 절삭가공의 경제성 및 환경비용을 평가하였다. 가공시간 및 가공비용이라는 절삭공정의 경제성 평가 모델과 더불어 수학적으로 모델링 된 절삭유제의 손실량 및 폐 유제 처리비용을 이용하여 환경비용을 고려한 절삭공정의 생산비용을 분석하였다. 분석에는 CBN 볼 엔드밀을 사용한 고속가공과 여러가지 냉각방식을 적용한 고속 선삭가공 공종에 대한 공수수명 및 공구마모 실험 데이터를 이용하였다. 고속 밀링가공에서 절삭속도가 높을수록 생산비용은 작아져서 고속가공의 장점을 그래도 보여주었다. 압축공기, 냉풍, 수용성 절삭유제, 건식 절삭의 네 가지 냉각방법을 사용한 선삭가공의 분석에서는 절삭유제를 이용한 냉각방식이 절삭유제를 사용하지 않은 방식에 비하여 공수수명의 향상으로 생산비용이 작았으나 환경비용을 고려하면 냉풍을 이용한 냉각방식이 생산성과 환경영향의 모든 면에서 가장 우수하였다.

• 산업경영시스템학회지
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• 제45권4호
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• pp.61-69
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• 2022

The function of coolant in machining is to reduce the frictional force in the contact area in between the tool and the material, and to increase the precision by cooling the work-piece and the tool, to make the machining surface uniform, and to extend the tool life. However, cutting oil is harmful to the human body because it uses chlorine-based extreme pressure additives to cause environmental pollutants. In this study, the effect of cutting temperature and surface roughness of titanium alloy for medical purpose (Ti-6Al-7Nb) in eco-friendly ADL slot shape machining was investigated using the response surface analysis method. As the design of the experiment, three levels of cutting speed, feed rate, and depth of cut were designed and the experiment was conducted using the central composite planning method. The regression expressions of cutting temperature and surface roughness were respectively obtained as quadratic functions to obtain the minimum value and optimal cutting conditions. The values from this formula and the experimental values were compared. As a result, this study makes and establishes the basis to prevent environmental pollution caused by the use of coolant and to replace it with ADL (Aerosol Dry Lubricant) machining that uses a very small amount of vegetable oil with high pressure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.15-19
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• 2002

With the rapid development of industrial technologies, the demand for high precision products has been increasing drastically. For this reason, the need for developing of high performance machine tool, which can ensure high precision, is desired in the industrial fields. Technologies on the spindle system manufacture, guideway manufacture, error compensation, design of bed structure, protection against vibrations, and system integration are core technology for developing of high precision machine tools. Especially, among these, design of spindle system, which is leading precision and manufacturing technique. is one of the most important technologies. A high speed and high precision spindle system, which will be used for final machining of ferrule, is designed considering the effect caused by thermal, cutting torque, cutting farce, and work-piece materials. The detail process of analysis is presented.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.411-415
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• 2004

In this paper, a double artificial neural network (ANN) approach and the efficient machining database building scheme are presented for the prediction of surface roughness in high-speed machining. In this approach, 4 machining parameters and used for the prediction of cutting force components, and the combinations of 4 parameters and the predicted cutting force components are finally used for the prediction of surface roughness. The experimental results comparing the these results with the predicted values using simple 4 input nodes have been also investigated to verify the effectiveness of the proposed approach.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.221-226
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• 1999

It can be acquired the high effective productivity through of high speed, precision of machine tools, and then, machine tools will be got a competitive power. Industrially advanced countries already developed that the high speed feed is 50m/min using the high speed ball screw. Also, a lot of problems have happened the feed and servo drive system. It is necessary to study about the character of positioning accuracy, heat generation and high speed/accuracy control for feed/servo drive system of high speed/accuracy. In this study, we make use of high performance vertical machine center with a ball screw of large-scale-lead. Also, we'll apply the high-speed/accuracy control technology in this part of feedforward control, multi-buffering block size, etc. Using the design of the mechanical element and high-speed precision control, the basic design concept can be established.

• 한국기계가공학회지
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• 제2권3호
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• pp.5-12
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• 2003

In order to reduce the lead-time and cost, many useful methods have been applied to rapid prototyping (RP) in recent years. But cutting process is still considered as one of the effective RP methods that have been developed and currently available in the industry. It also offers practical advantages in aspects of precision and versatility. However, traditional 3-axis NC machining has some inherent limitations such as the restriction of tool accessibility and the complex setup. In this work, a new rapid prototyping system with high speed 5-axis machining of plastics has been developed to overcome those limitations. And cutting experiments were conducted to determine the design factors of the system and the cutting conditions of plastics. The architecture of developed system is described in detail and the successful application examples are presented.