• Transactions of Materials Processing
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• v.18 no.2
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• pp.166-171
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• 2009

In this paper, a basic study on micro cutting process with SM20C at low temperature environment was performed. In macro cutting fields, the cryogenic cutting process has been applied to cut the refractory metal but, the serious problem may be generated in micro cutting fields by the cryogenic environment. However, if the proper low temperature is applied to micro cutting area, the cooling effect of cutting heat is expected. Such effect can make the reduction of tool wear and burr formation. For verifying this possibility, the micro cutting experiment at low temperature was performed and SEM images were analyzed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.4
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.265-270
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• 1995

In orthogonal cutting a new approach for modeling of burr formation process when tool exits workpiece is proposed. The approach is based on the rigid-plastic FEM combined with the ductile fracture criterion and the element kill method. The approach is applied to simulate a plane strain cutting process. The results of the FEM are compared with those of the experiment. It is shown that the fracture location and fracture angle as well as cutting force can be predicted using the proposed approach with a good correlation to experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.6
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• pp.401-409
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• 2016

The formation of micro-burrs in micro-milling processes causes several problems related to productivity and surface integrity. It should be minimized and suppressed by effective monitoring of the cutting conditions. This paper presents the correlation between the micro-burr length and cutting signals in the micro-milling process of an Al alloy (Al6061-T6). The acoustic emission (AE) signals and cutting force signals are acquired during the experiments. The characteristics of the cutting signals are obtained by analyzing the AE root mean square value and resultant cutting force. In addition, the micro-burr length is measured according to the cutting conditions by analyzing a scanning electron microscopy image of the machined surface. The results of this study can be used to enhance the surface quality of micro parts.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.3
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• pp.30-39
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• 1986

The burr worsens the accuracy of a workpiece and decreases a lot of pro- ductivity because it takes so much time and efforts to remove it. In this paper, the height, thickness and size of a drilling burr were derived from the drilling variables of drill diameter, chisel edge angle, web rate =($\Frac{2{\times}\;web\;thickness}{drill\;dia}$) and yielding stress of the workpiece as wel as feed, point angle and helix angle. The theoretical and experimental values of drilling thrust, torque and burr size of the testpiece were analyzed with the method of numerical analysis in a standard drilling condition. The order of choosing the drilling variables for the purpose of controlling the burr size was dealt in this paper with burr forming ratio. The results are as follows: (1) The drill diameter forms 42 percents feed 25 percents point angle 23 percents and web rate, chisel edge angle and gelix angle 5 percents of the partial differential slope of drilling thrust within the usual available ranges of drilling variables. (2) The drill diameter forms 55 percents feed 26 percents web rate 9 percents and chisel edge angle, point angle and helix angle 10 percents of the par- tial differential slope of drilling torque in the usual available ranges of drilling variables. (3) About 70 percents of the burr size can be controlled by feed, 29 percents by web rate in the case of a fixed diameter. It is recommended drilling10 variables to be chosen in the order of feed, web rate, drill diameter, point angle, chisel edge angle and helix angle so as to control the burr size effectively.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.3
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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.

• Transactions of Materials Processing
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• v.13 no.1
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• pp.65-71
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• 2004

Recent electronic equipment becomes smaller, more functional, and more complex. According to these trends, LTCC(low temperature co-fired ceramic) has been emerged as a promising technology in packaging industry. It consists of multi-layer ceramic sheet, and the circuit has 3D structure. In this technology via hole formation plays an important role because it provides an electric path for the packaging interconnection network. Therefore via hole qualify is very important for ensuring performance of LTCC product. Via holes are formed on the green sheet that consists of ceramic(before sintering) layer and PET(polyethylene terephthalate) one. In this paper we found the correlation between hole quality and process condition such as PET thickness and ceramic thickness. The shear behavior of double layer sheet by micro hole punching which is different from that of single layer one was also discussed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.2
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• pp.17-21
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• 2007

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.19-22
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• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely using for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experimental investigation to examine the influence of shearing processes parameters such as clearance, cutting angle, material properties, etc. From the results of experiment, it has shown that it gives the small variations at burr height below the proper clearance and it also presents that it is no affected the variations of cutting angle.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.231-234
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• 2001

Shearing, including blanking, trimming, piercing, etc, is one of the most frequently used processes in sheet metal manufacturing. In this paper, an individual set of tooling with an in-die sensor was designed and precisely fabricated to carry out the experiment for the shearing process investigation. Through various experiments, it has been examined the influence of process parameters such as clearance, edge material properties and pad configuration. Since the tension between the part and the scrap increases when the clearance increases, the clearance should be selected properly in order to reduce the burr height. Also removal of the lower pad makes the sheared surface worse and the shearing system unstable. The shearing force increases when the clearance decreases and the friction of the tooling material decreases. Dynamic reaction force is also important to obtain the fine sheared surfaces.