• 한국정밀공학회지
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• 제23권9호
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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.

• 한국정밀공학회지
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• 제17권3호
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• pp.114-121
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• 2000

A new concept drill was developed recently (or increasing accuracy and productivity in drilling operation. The burr formation in drilling causes many problems in deburring operation because burrs are formed inside holes and it is difficult to remove them. Burr formations are observed in drilling operation with a new concept drill and are compared with conventional HSS drill. Several workpieces with different materials are drilled with several cutting conditions, velocity and feed rate. The burr in drilling can be classified into three types according to the location of crack. To observe the burr formation mechanism, the cap which is formed with the new concept drill is observed and measured.

• 한국정밀공학회지
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• 제17권10호
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• pp.132-140
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• 2000

In conventional drilling, burr geometry can be changed according to the variation of drill geometry like point angle, rake angle. Step drilling is proposed to minimize the burr formation in drilling operation. The burr formed in first cutting can be removed in second cutting by the edge in step. The burr formed in second cutting by the edge in step can be minimized according to the change of geometry like, step angle and depth. The mechanism in step drilling is analyzed. Some step drills are applied to drilling the input shaft which is used for vehicle steering. To measure the burr formed in drilling, laser and height gage are used.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.968-975
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• 2005

The shearing process for the sheet metal is normally used in the precision elements such as semi-conductor components. In these precision elements, the burr formation brings a bad effect on the system assembly and demands the additional de-burring process, so this imposes high cost on manufacturing. In this paper, we have developed the in-situ auto-aligning precision meso-punching system to investigate the burr formation mechanism and ultimately minimize burr. Firstly, we introduced the punch-die contact sensing method to align the punch and the die at initial state prior to the punching process. Secondly, by using the low-price semi-con­ductor laser, burr formed on the edges is measured intermittently during the punching process. We could, finally, make burr on the sheet metal uniformized and minimized by controlling of the precision X - Y table, $1\;{\mu}m$ resolution, and measuring burr height by semiconductor laser. Experimental results show the validity of our system for pursuing the burr-free punched elements.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.434-438
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• 2003

The shearing process for the sheet metal is normally used in the precision elements such as semi-conductor components. In these precision elements, the burr formation brings a bad effect on the system assembly and demands the additional de-burring process. In this paper, we have developed the desktop-type precision punching system to investigate the burr formation mechanism and present kinematically Punch-die auto aligning methodology, for the purpose of burr unifomizing and minimizing, between the rectangular shaped punch and die. By using the scanning electron microscope, the aligned punching results are compared with the miss-aligned ones. Also, we measured the relative burr heights using the self-designed laser measuring device for insitu self aligning. Since it is hard to get the perfect, so called, burr-free edges during the shearing process, we introduced the ultrasonic do-burring machine. The de-burring operation was carried out by a novel do-burring method, the reversal flow resistance method, under different machining loads and abrasive types. The final do-burring results show the validity of our punching do-burring system pursuing the burr-free punched elements.

• 한국정밀공학회지
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• 제21권7호
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• pp.70-75
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• 2004

The shearing process for the sheet metal is normally used in the precision elements such as a lead frame of IC chips. In these precision elements, the burr formation brings a bad effect on the system assembly and demands the additional deburring process. In this paper, we developed the small size precision punching system to investigate burr formation mechanism and to present kinematically punch-die aligning methodology between the rectangular shaped punch and die. The punch is driven by an air cylinder and the sheet metal is moving on the X-Y table system which is driven by two stepping motors. The whole system is controlled by microprocessor and is communicated with each other by RS232C serial communication protocol. Punching results are measured manually using the SEM photographs and are compared aligning result with miss aligning one.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.100-104
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• 1996

This paper describes the characteristics of micro-burr formation in the cross hatch and deburring in honed surfaces. Two types of micro-burrs formed in the cross hatch were defined as upper edge burr (type A) and side edge burr (type B). The size of micro-burrs were measured for the honed surfaces of several cross hatch angle. Deburring mechanism and system using magneto-electrolytic process including the abrasive pad for mechanic deburring effects together were introduced. Deburring experiments and analysis were carried out to confirm the effectiveness of the deburring process.

• 한국기계가공학회지
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• 제5권3호
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• pp.51-57
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• 2006

Hydro-mechanical punching was developed for preventing burr formation. Circular hole punching and Finite element method(FEM) analysis were conducted to investigate shearing characteristics of this process in comparison with conventional and mechanical counter punching. In this process hydrostatic pressing with appropriate medium was utilized instead of counter punch, which resulted in the delay of the point that the fracture is initiated and clean shearing surface was obtained. FEM analysis was utilized to find out optimum processing parameters and shearing mechanism for burr-free hole punching.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.14-20
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• 2002

Recently, miniaturization and mass production are the main trends in manufacturing fields. Therefore, ultraprecision machining and MEMS technology have been taken more 7md more important position in machining of microparts. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from duo parts to micro products, such as PDP md IT components, in precision products manufacturing. However, decreasing of burr is significant problem in making smooth and precise parts in micro endmilling. This paper shows removal characteristics of burr generated by micro endmilling process. This results satisfies micro endmilling for micro barrier ribs of heights is $50{\mu}m$, $100{\mu}m$, $200{\mu}m$, $300{\mu}m$, and observation from of burr. Additionally, it is necessary to understand the formation mechanism of burr of micro barrier ribs to iud proper decreasing method.

• 한국기계가공학회지
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• 제9권4호
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• pp.38-43
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• 2010

By generating 2-directional vibration in a xy plane of workpiece table, a newly developed micro drilling using 2-directional vibration was carried out. The vibration was produced by applying sinusoidal voltages to the orthogonally arranged piezoelectric materials built in the workpiece excitation table. Through the micro-drilling experiments using poly-carbonate and brass material, it was found that micro drilling using 2-directional vibration in a workpiece table could be an efficient method to enhance the form accuracy of machined workpiece by suppressing burr formation at both entry and exit region. A higher form accuracy could be obtained by increasing stiffness of feeding mechanism, decrease of geometric tolerance of combining jig, and development of high performance excitation table which generates amplified vibration at higher frequency.