• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.466-469
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• 2002

Burr is a projected part of finished workpiece. It is unavoidable and undesirable by-product of most metal cutting or shearing process. Also, it must be removed to improve the fit of machined parts, safety of workers, and the effectiveness of finishing operation. But deburring process is one of manufacturing processes that have net been successfully automated, so deburring automation is strongly needed. This paper focused on developing a basic algorithm to find edge of workpiece and match two different image data for deburring automation which includes automatic recognition of parts, generation of deburring tool paths and edge/corner finding ability by analyzing the DXF drawing file which contains information of part geometry. As an algorithm for corner finding, SUSAN method was chosen. It makes good performance in finding edge and corner in suitable time. And this paper suggested a simple algorithm to find matching point between CCD image and drawing file.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1121-1140
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• 1992

In metal cutting the shape of generated chip varies according to cutting conditions, characteristics of workpiece and geometry of cutting tool. The best surface roughness of machined workpiece is obtained when generating flow type contrinuous chip. If the generated chip is not broken, that is not only tangled workpiece and cutting tool, but also may give damage on the machined surface of workpiece or danger for a operator. The flow type continuous chip may bring the low productivity in high speed any heavy cutting, automatic machining process and non-human factory. There are two type of chip break process ; controlling cutting condition and using chip breaker. In present study we carried out the experiment on new type chip breaker compared with conventional type and proved the efficiency of a new type and showed the chip break condition to be applied in actual metal cutting. In the experiment SM 20 C as a workpiece material and WC as a tool material were used and cutting speed of 30-150m/min, feed of 0.071-0.210mm/rev and depth of cut of 1mm were applied as cutting condition. The results of the experiment are as follows : (1) The mechanism of chip curl can be explained more clearly by plastic flow of workpiece material and moment of shearing force. (2) The most effective radius of curled chip and flat distance from cutting edge is 2.0-2.5mm and 1.5mm in both types. (3) The effective inclination angle of chip break surface and side cutting edge angle are 30.deg.- 45.deg. and 20.deg. in conventional type, while the radius of arc surface, lower arc angle A, upper arc angle B and side cutting edge angle are 3mm, 20.deg.- 45.deg., 0.deg.- 45.deg. and 10.deg.- 20.deg. in new type. (4) The probability to be obtained 100% chip breaking ratio is much higher in new type than in conventional type.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1807-1810
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• 2003

The formed tool is used to machine the unique shape of rubber seal for geometrical shaping and reduction of cutting time. The bearing rubber seal produced by hot press forming has complex geometry for the complex geometrical shape to prevent leakage of lubricant oil and influx of the dust effectively. Because it is difficult to machine the unique shape exactly by the conventional tool, the formed tool is used in machining mold of the seal. In this paper, It is performed for selection of the formed tool to investigate cutting edge wear, cutting force, and surface quality. Also, an efficient high precision machining is proposed on the experiment data.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.234-243
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• 1999

Using the geometric and the vector methods, three dimensional surface texture and roughness models in flat end milling are developed. In these models, rear cutting effect on surface generation is considered along with tool run-out and tool setting error including tool tilting and eccentricity between tool center and spindle rotational center. Rear cutting is the secondary cutting of the already machined surface by the trailing cutting edge. The effects of tool geometry and tool deflection on surface roughness are also considered. For representing the surface texture more practically, three dimentional surface topography parameters such as RMS deviaiton, skewness and kurtosis are introduced and used in expressing the surface texture characteristics. Under various cutting conditions, it is confirmed that the developed models predict the real surface profile precisely. These models could contribute to the cutter design and cutting condition selection for the reduction of machining and manual finishing time.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.92-98
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• 2002

End mill is an essential tool to generate complex surface in workpiece and it has been developed with various materials and tool shapes. The most important factor to evaluate the performance of end mill is still the wear characteristics of flank face. In addition to the flank wear, the tool edge roughness generated by the chipping is another important factor in aspects of material property and machinability evaluation and affects the quality of machined surface. Up to now, there is no direct method for measurement of tool edge roughness. In this study, the tool edge roughness of flat end mill is indirectly measured along the axial direction of workpiece. The theoretical equation is derived in consideration of tool geometry. Finally, the optimal conditions to measure the tool edge roughness by the proposed method are presented through the theoretical review and experimental identification.

• Design & Manufacturing
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• v.14 no.3
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• pp.63-70
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• 2020

As the consumer market in the VR(virtual reality) and the head-up display industry grows, the demand for 5-axis machines and grooving machines using on a ultra-precision machining increasing. In this paper, ultra-precision diamond tools satisfying the cutting edge width of 500 nm were developed through the process research of a focused ion beam. The material used in the experiment was a single-crystal diamond tool (SCD), and the equipment for machining the SCD used a focused ion beam. In order to reduce the influence of the Gaussian beam emitted from the focused ion beam, the lift-off process technology used in the semiconductor process was used. 2.9 ㎛ of Pt was coated on the surface of the diamond tool. The sub-micron tool with a cutting edge of 492.19 nm was manufactured through focused ion beam machining technology. Toshiba ULG-100C(H3) equipment was used to process fine-pattern using the manufactured ultra-precision diamond tool. The ultra-precision machining experiment was conducted according to the machining direction, and fine burrs were generated in the pattern in the forward direction. However, no burr occurred during reverse machining. The width of the processed pattern was 480 nm and the price of the pitch was confirmed to be 1 ㎛ As a result of machining.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.47-53
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• 2006

An Experiment was carried out to find the scheme far minimization of burr formation on inclined exit surface in drilling. Several drills with different geometry are used for drilling the workpiece with inclined exit surface. Step drills are specified with step angle and step size. The influence of the inclination angle of exit surface on burr formation was observed, which enables to analyze the burr formation mechanism on inclined exit surface. Along the edge on the inclined exit surface, burrs are formed by the bending deflection to feed direction and also burrs are formed in exit direction of cutting edge. To minimize the burr formed in feed direction, the corner angle which is formed by the inclination angle and step angle must be large enough not to be bent to burr. By decreasing step angle of drill and decreasing the distance between two axes of two holes, burr formation at the intersecting holes can be minimized. Burr formation mechanisms are analyzed according to the drill geometries and cutting conditions. Several schemes far burr minimization on inclined exit surface were proposed.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.21-26
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• 2004

The formed tool is used to machine the geometrical shape of bearing rubber seal efficiently. The bearing rubber seal has complex geometry for the complicated geometrical shape to prevent leakage of lubricant oil and influx of the dust effectively. Because it is difficult to machine the unique shape exactly by the conventional tool, the formed tool is used in machining a rubber seal die. In this paper, It is performed to investigate machining characteristic of the formed tool； cutting edge wear, cutting force, and surface quality. Also, an efficient precision machining condition is proposed, and the inspection results of rubber seal with CAI are discussed.

• Transactions of Materials Processing
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• v.12 no.3
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• pp.208-213
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• 2003

The methodology to design initial blanks considering the reduction of both springback and flange trimming amounts is studied. Three dimensional forming analysis of a trial blank Is first carried out using FEM and the tentative Initial blank shape is then determined by cutting the outer edge of the trial blank whose shape is nearly matched with the trimming line. During the shaping the blank edge, tile movement of blank outer line is described with random variables to reduce the sensitivity of initial blank geometry. After performing 2-D FEM forming and springback simulations for selected sections and optimizing the trimming and springback amounts in terms of section length of the blank, the initial blank is finally determined. In order to see tile springback reduction in the initial blank determined by the proposed method, a stepped s-rail is stamped and the sppingback is measured. The springback of newly designed initial blank of stopped s-tail is tremendously reduced.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.164-174
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• 1996

As tools for machining precision componants, end mills and ball end mills are widely used. For the end mills have longer cylindrical shape comparing dianeter, they are liable to deflect when machining and induce geometrical error and deterioration of surface roughness. To improve the stiffness and the sharpness of the cutting edge of end mill, a software for manufacturing end mills are developed. The program predicts the result of helical flute grinding and the configuration of cuting edge which is located in cylindrical surface. Furthermore to facilitate the manufacturing end mills using CNC grinding machine, the setting condition which satisfy the geometrical requirements like tool rake angle and stiffness are obtained.