• 한국정밀공학회지
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• 제27권9호
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• pp.86-93
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• 2010

Any relative deformation between the cutting tool and the workpiece at the machining point, results directly in form and dimensional errors. The source of relative deformations between the cutting tool and the workpiece at the contact point may be due to thermal, weight, and cutting forces. Thermal and weight deformations can be measured at various positions of the machine tool and stored in the compensation registers of the CNC unit and compensated the errors during machining. However, the cutting force induced errors are difficult to compensate because estimation of cutting forces are difficult. To minimize the error induced by cutting forces, it is important to improve the machining accuracy. This paper presents the pre-calculated method of form error induced by cutting forces. In order to estimate cutting forces, Isakov method is used and the method is verified by comparing with the experimental results. In order to this, a cylindrical-outer-diameter turning experiments are carried out according to cutting conditions.

• 한국정밀공학회지
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• 제27권4호
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• pp.20-26
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• 2010

Any relative deformation between the cutting tool and the workpiece at the machining point, results directly in form and dimensional errors. The source of relative deformations between the cutting tool and the workpiece at the contact point may be due to thermal, weight, and cutting forces. This paper presents an investigation into dry and fluid machining with the objective of evaluating shape accuracy effect for the turning process of Al6061. The thermal distribution of cutting tool and cutting force was predicted using finite element method after measuring the temperature of the tool holder. To reach this goal, shape accuracy turning experiments are carried out according to cutting conditions with dry and fluid machining methods. The variable cutting conditions are cutting speed, depth of cutting and feed rate.

• Journal of Biosystems Engineering
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• 제28권3호
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• pp.209-216
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• 2003

Red pepper calyx cutting devices using a impacting force by a rotational cutter were devised and tested to obtain the fundamental data for development of a calyx removal unit. Fresh red peppers with 80∼87%(w.b.) of initial moisture contents were used as experimental materials. Square and wire type of rotational cutters were used to cut the red pepper calyx and the fresh red peppers were fed into the device both manually and automatically. Three rotational speeds of 250, 500, 700rpm were selected for a square, and 1000, 1500, 1800rpm for a wire type cutter respectively. Four types of red pepper fixing unit were used in manual feeding. The cutting rate of the square type cutter was over 50% regardless the shape and specification of the cutter. For the wire type cutter, the copper wire and nylon chord could not be applied to cut the red pepper calyx because of the low cutting rate. But for the fine wire, the cutting rate was higher and the cutting mechanism was more steady than copper wire and nylon chord. The cutting rate of automatic feeding and wire type cutting unit was about 70% for all levels of the rotational speed. The cutting rate was highly related to the impacting point of red pepper in carrier box. To increase the cutting rate using the rotational cutter, a proper device and mechanism was required to keep the impacting point consistently.

• 대한기계학회논문집
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• 제9권4호
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• pp.440-451
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• 1985

본 논문에서는 곡면절삭력계의 해석을 통하여 절삭성과 내마멸성이 우수한 공 구기하형상과 곡면절삭과정에서 절삭조건에 따라 변화하는 가공정밀도 및 안정성을 규 명하고자 한다.

• 한국생산제조학회지
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• 제6권4호
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• pp.138-146
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• 1997

The optimal drill helix angle, point angle, and cutting conditions are recommended in the study so as to maximize the drilling performance by investigating the experimental reaults concerning with the state of chip formation, roundness of machined holes, and geometry of projected burr at hole exit, which are examined under the conditions of various helix angles, drill point angles of twist drill, cutting speeds, and feeds in operional parameters. In the easiness of chip escape, the helical type of chip is producted when a helix angle is 30$^{\circ}$, drill point angle 118$^{\circ}$, 140$^{\circ}$and feed is st between 0.1 and 0.15mm/rev. Roundness of machined hole is improved when the helix angle is 37$^{\circ}$, drill point angle is 118$^{\circ}$, and feed is 0.15mm/rev. The height of projected burr at the button of machined hole increases when the drill point angle and helix angle becomes large.

• 한국CDE학회논문집
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• 제6권2호
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• pp.69-77
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• 2001

This paper describes a method of calculating the feedrate for the constant cutting speed at a CL-point in 5-axis machining. Unlike 3-axis machining, 5-axis machining has the flexibility of the tool motions due to two rotation axes. But the feedrate at joint space differs from the feedrate at a tool tip(the CL-point) of the 3D Euclidean space for the tool motions. The proposed algorithm adjusts the feedrate based on 5-axis NC data, the kinematics of a machine, and the tool length. The following calculations is processed for each NC block to generate the new feedrate; 1) calculating the moving distance at the CL-point, 2) calculating the moving time by the given feedrate, 3) calculating the feedrate of each axis, 4) getting the new feedrate. The proposed algorithm was applied to a 5-axis machine which had a tilting spindle and a rotary table. Totally, the result of the algorithm reduced the machining time and smoothed the cutting-load by the constant cutting speed at the CL-point.

• 한국정밀공학회지
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• 제20권6호
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• pp.20-26
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• 2003

This study proposes the construction of attractor quadrant method for high-precision cutting characteristics evaluation of non-ferrous metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of non-ferrous metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to Perform cutting Processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics and attractor quadrant characteristics. In quantitative quadrant feature extraction, 1,309 point in the case of A17075 (one quadrant) and 1,406 point (one quadrant) in the case of brass were proposed on the basis of attractor reconstruction. Proposed attractor quadrant method can be used for high-precision cutting characteristics evaluation of non-ferrous metals.

• 한국수산과학회지
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• 제1권2호
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• pp.129-133
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• 1968

The writer reviewed the cutting method of webbing practiced in major countries. Cutting rhythm Bar cutting to Point Cutting) should be chosen to approach as straight as possible, therefore the knot cuttings or the side cuttings should be 1, if possile. According to calculation, an arbitrary solution to a mixed cutting was undertaken, while another cutting method, of calculation 5 and 6, was taken by a prepared table. In no case, it was consequently possible to use an unmixed cutting rhythm. Sometimes, the cutting calculated from approximate value differs from desired result, tut this defference should not be taken too significant in practice.

• 대한기계학회논문집
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• 제17권6호
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• pp.1456-1464
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• 1993

본 논문에서는 다이아몬드 공구를 사용한 절삭과정에 대하여 절삭력 관계식을 제안하고, 이를 실제 천연 다이아몬드 공구를 이용하여 알루미늄 합금을 절삭하는 실험해석을 통하여 절삭력을 예측하는 모델을 세우고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.85-91
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• 1996

The drilling experiment of carbon fiber epoxy composite material with WC-drill has been done under the various cutting condition in order to minimize the problems occured in the material when being drilled. It has been comfirmed by a frequencyanalysis of the cutting force signals that the variation of cutting force resulted from the periodic variation of the angle between the rotating drill and the stacking angle of the carbon fiber. The drilling experiment has been done with several drills having different point angles and the drilling characteristics, like the effects such that change in the point angle influences the cutting force and the external surface condition, was evaluated.