• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.1-5
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• 1997

The plane surface rolling, one of the plastic working process, good surface condition due to increase of surface roughness and hardness. It is well known that mechanism of surface rolling depends upon rolling conditions such as rolling speed, contact pressure, step length of rolling, the shape of roller and mechanical properties of material. In this study, the optimal value of the above parameter on the surface roughness were investigated by using the rolling tool with NACHI 6000ZZ ball bearing outer races on machine structure carbon steel[SM45C]

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.19-25
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• 2001

In metal cutting, chatter is an unstable cutting phenomenon which is due to the interaction of the dynamics of the chip removal process and the structural dynamics of machine tool. When chatter occurs, it reduces tool life and results in poor surface roughness and low productivity of the machining process. In this study, the experiments have been conducted to investigate phenomenon of the chatter in CNC lathe without cutting fluid. In the experiments, two accelerometers were attached at the tail stock and tool holder and the signals were caught. In order to observe the effect of chatter on the surface roughness profiles, surface roughness profiles were generated under the ideal condition and the occurrence of the chatter based on the surface simulation model using surface-shaping system. Finally, the result of experiment and simulation have been compared.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.362-367
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• 2003

Recentlry, High accuracy and precision are required in various industrial field. To obtain the surface roughness with range from several 10nm to several nm in inner cutting, we need a ultra-precision machine, single diamond tool, cutting condition, and the study of materials. It is very difficult to obtain the mirror surface without new technique. In this paper, Using the new tool holder as well as the ultra precision diamond cutting, we directly processed the inside of an aluminum alloy in order to obtain mirror surface. We have considered the length of tool holder when we design the tool holder. From experimental results, we believe that the new tool holder will improve inner cutting.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.5-14
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• 2002

Hemisphere shapes were machined for different tool paths and machining conditions with ball endmill cutters. It was also found out how feedrate affect the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Tool deflection, cutting forces and shape accuracy were measured according to the inclination position of the sculptured surface. As the decreasing of inclination position angle, the tool deflection was increased due to the decreased cutting speed when the cutting edge is approaching toward the center. Tool deflection when upward cutting IS obtained less than that of downward cutting and down-milling in upward cutting showed the least tool deflection for the sculptured surface. For down-milling, the cutting resistance of the side wall direction is larger than that of feed direction. It was found that the tool deflection is getting better as tool path is going to far from the center for convex surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1001-1004
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• 2000

As tools for machining precision components, end mills and ball end mills are widely used. For the end mills have longer cylindrical shape comparing diameter, liable to deflect and induce deterioration of surface roughness. Tool geometry parameters and cutting process have complex relations with each other. So, It is hard to determine hew to select optimal tool geometry. So, to improve the stiffness, relationship between cutting process and tool geometry must be studied. In this study, relations between grinding wheel geometry, setting condition and tool geometry are revealed. For the purpose of studying relations between each parameter, the equivalent diameter of tool has been calculated assuming tool as a simple beam. By the various cutting simulations and experiments, tool geometry and cutting process has been studied.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.878-881
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• 2000

Recently high speed machining is being studied actively to reduce machining time and to improve machining precision. To perform efficient high speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force, tool wear and surface roughness. In this study. the cutting force and tool wear and surface roughness are investigated in case of various cutting conditions for hardened die steel.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.37-43
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• 1995

The cutting process of cage motor rotor require high precision and good roughness, the surface roughness fo cutting face is very important factor with effect on the magnetic flux density of cage motor rotor. The paper describes a cause of decrease in the cutting force and roughness on low temperature cooling tool by means of analysis on the mechanism of force system at cutting condition and experimental findings. The main results as compared with the room temperature cutting are as follow : 1) The cutting resistance decreased due to low temperature cooling tool. 2) The surface roughness decreased due to low temperature cooling tool. 3) The low temperature cooling tool effected machinability of the cutting direction in machined surface. 4) The low temperature cooling decreased burr of corner in feed direction.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.39-46
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• 2003

Productivity and machining performance can be improved by cutting analysis including cutting force prediction, surface error prediction and machining stability evaluation. In order to perform cutting analysis, cutting force coefficients database have to be constructed. Since cutting force coefficients are dependent on cutting condition in the existing research, a large number of calibration tests are needed to obtain cutting force coefficients, which makes it difficult to build the cutting force coefficients database. This paper proposes a generalized method for constructing the cutting force coefficients database us ins cutting-condition-independent coefficients. The tool geometry and workpiece material were considered as important components for database construction. Cutting force coefficients were calculated and analyzed for various helix and rake angles as well as for several workpiece. Furthermore, the variation of cutting force coefficients according to tool wear was analyzed. Tool wear was found to affect tool geometry, which results in the change of cutting force coefficients.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.19-24
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• 2003

Recently, various efforts to make more speedy and precision machine tool to improve productivity and also various efforts to solve environmental problem are going on, so that dry cutting in manufacturing industry, which needs environmental conscious design and development of manufacturing technique, is becoming a very important assignment to solve. Because dry cutting does not use cutting fluid, we need other methods that can be used instead of cutting fluid, which does cooling, lubricating, chip washing, and anti-corrosion. Especially, because turning is a continuous work, the consideration of tool life and surface roughness due to continuous heat and poor lubrication is important. The purposes of this paper are the consideration of how well the compressed air can work instead of cutting fluid, and also the development of the method to select the optimum machining condition by the minimum numbers of experiments through the Taguchi method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.833-837
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• 2000

The purpose of this study is an evaluation of end mills to develop appropriate tools for the high speed machining. First of all, several flat end mills which are produced by different makers are selected to analyze the performances of the tools. Experimental works are also executed to measure cutting force, tool wear and surface roughness for different cutting conditions. And then the results are compared and analyzed for developing optimal cutting tool in the high speed condition. Especially, analysis about tool wear is introduced in this research.