• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.135-144
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• 1998

High speed machining is a key issue in die and mold manufacturing recently. Even though this technology has great potential of high productivity. tool wear accelerated by high cutting speed to the hardened materials is other barrier. In this research, we attempted to reduce tool wear by considering tool inclination angle between tool and workpiece. The boundary lines describing machined sculptured surfaces were represented by both of cutting envelop condition and the geometric relationship of successive tool paths. Chip cross section, and cutting length could be obtained from the calculated cutting edge and the rotational engagement angle. From the simulation results, machining inclination angle of tool of $15^\circ$ was good enough from the point of tool wear and cutting force, and this value was verified through the cutting experiment of high speed ball end milling.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.5
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• pp.852-858
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• 2013

In numerical control (NC) machining, a machining error in equipment generally occurs for a variety of reasons. If there is a change in direction in the NC code, the characteristics of the automatic acceleration or deceleration function cause an overlap of each axis of the acceleration and deceleration zones, which in turn causes a shift in the actual processing path. Many studies have been conducted for error calibration of the edge as caused by automatic acceleration or deceleration in NC machining. This paper describes a geometric interpretation of the shape and processing characteristics of the operating NC device. The paper then describes a way to determine a feedrate that achieves the desired tolerance by using linear and parabolic profiles. Experiments were conducted by the validate equations using a three-axis NC machine. The results show that the machining errors were smaller than the machine resolution. The results also clearly demonstrate that the NC machine with the developed system can successfully predict machining errors induced with a change in direction.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.119-124
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• 2017

Machining optimization using typical computer-aided manufacturing (CAM) software mainly depends on tool paths, and it is impossible to predict the behavior of material or cutting force. In this paper, cutting force analysis simulation is performed on the Unibody Case of a mobile phone with the aim of optimizing cutting-force-based machining using the Third Wave Systems' AdventEdge Production Module. Machining time after optimization was shortened by 42% for roughing compared to pre-optimization, and actual machining time was reduced by 36.8%. For finishing, machining time was reduced by 92%, and actual machining time was reduced around 90%. A surface roughness analysis found that the post-optimization surface roughness was $1.16{\mu}m$ Ra, compared to a pre-optimization value of $1.75{\mu}m$ Ra.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.123-129
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• 2022

Quartz (SiO2) has high abrasion and heat resistances and excellent chemical and mechanical properties; therefore, it is used in various industries, such as machinery, chemistry, optics, and medicine. Quartz is a high-hardness and brittle material and is classified as the topmost difficult-to-cut material, which is because of the cracking or chipping at the edge during processing. Corner wear, such as cracks and chippings that occur during cutting, is a major cause for the deterioration in the machining quality. Therefore, many researchers are investigating various techniques to process quartz effectively. However, owing to the mechanical properties of quartz, most studies have been conducted on grinding, micromachining, and microdrilling. Few studies have been conducted on quartz processing. The purpose of this study was to analyze the machining characteristics according to the machining factors during the slot machining of quartz using a cubic boron nitride (CBN) tool and to select the optimal machining conditions using the Taguchi method. The machining experiment was performed considering three process variables: the spindle speed, feed rate, and depth of cut. The cutting force and surface roughness were analyzed according to the processing conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.19-20
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• 2006

As the Mobile and Display technology are being developed quickly, new wireless devices are released in great numbers. They reduce existing devices' life time and demand a reduction of developing period of portable devices. With these demands, existing film cutting mold used many films of portable devices, especially LCD Display, needs to be more precise, and cheaper. In this research, we have analyzed machining characteristics of cutter shapes, materials, and cutting conditions for application to other films. Cutter edge was machined by slot cutting method and CAD program to select the cutter shape and cutter angle. Also, we have determined the optimal cutting conditions using high speed machining experiments to improve the productivity.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.149-155
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• 2001

Recently, it is required to design higher stage pressure ratio compressor while maintaining equal adiabatic efficiency. To increase the stage pressure ratio, blade rotational speed or diffusion factor should be increased. In the case of increasing rotational speed, relative speed of flow at blade leading edge is well supersonic. In supersonic blade, total pressure loss is mainly due to shock wave and blade leading edge thickness should be very thin to minimize the shock wave loss. As a result, the blade is like to be week in terms of mechanical strength and the manufacturing cost is very high because NC machining is necessary. It is also one of big hurdle to overcome to make small compressor. In this paper, the effects of blade leading edge to the performance of supersonic blade In terms of total pressure loss. The efficiency of already known method to make thin blade leading edge from the casted blade with rather thick leading edge thickness is also assessed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.18-24
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• 1999

ThisPaper investigates the feasibility of using acoustic emission signal analysis for the detection of built-up edge during machining. Experiments were conducted on a CNC-lathe using conventional carbide insert tools under various cutting conditions. The cutting forces were also measured for comparisons. Experimental evidence is presented which indicates that the presence of a built-up edge can significantly affect the generation of acoustic emission in metal cutting. It is shown that under conditions in which a built-up edge is generated, the variation of $AE_{rms}$ signal with cutting speed can be quite different from the generally accepted linear, monotonic increase as previously reported. The feasibility of utilizing $AE_{rms}$ in built-up edge sensing is suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.176-181
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• 1994

As tools for machining precesion componants, end mills and ball end mill are widely used. For the end mill have longer cylindrical shape comparing diameter, 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 manufaturing end mills are developed. The progeam predicts the result of helical flute grinding and the configuration of cutting edge which is located in cylindrical surface. Furthermore to facilitate the manufacturing end mill using CNC grinding machine, the setting conditions which satisfy the geometrical requirments like tool rake angle and stiffness are obtained.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.78-83
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• 1996

This paper presents the characteristics of surface roughness and cutting force in ultraprecision cutting of aluminium alloy using natural diamond tools whose edge radii are smaller than those of tools made of other materials. The feed rate and depth of engagement were set to be a micrometer order. After measuring the surface roughness of machined surface and cutting force for each cutting condition, the relations between the surface quality and its condition were investigated qualitatively. If the feed rate was under a certain limit, the machined surface quality was deteriorated unexpectedly. This is supposed to have happened due to vibration leading its condition to abnormal one. In a certain situation the machined surface roughness by a natural diamond tool was inferior to that made by a carbide tool whose cutting edge radius is larger. This is supposed to be caused by not normal machining but burnishing effect.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.150-157
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• 1996

In this paper, to develop a smart CAD/CAM system for systematically performing from the 3-D solid shape design of products to the CNC cutting operation of products by a machining center, a B-Rep solid modeler is realized based on the half edge data structure. Because the B-Rep solid modeler has the various capabilities related to the solid definition functions such as the creation operation of primitives and the translational and rotational sweep operation, the solid manipulation functions such as the split operation and the Boolean set operation, and the solid inversion function for effectively using the data structure, the 3-D solid shape of products can be easily designed and constructed. Also, besides the automatic generation of CNC code, the B-Rep solid modeler can be used as a powerful tool for realizing the automatic generation of finite elements, the interfer- ence check between solids, the structural design of machine tools and robots and so on.