• Journal of Welding and Joining
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• v.23 no.1
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• pp.86-93
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• 2005

Abrasive waterjet (AWJ) can provide a more effective means for precision of difficult -to-machining materials such as ceramics and titanium alloys. The present study is focused on the surface roughness of abrasive waterjet cut surfaces. This paper investigated theoretical and experimental surface characteristics associated with abrasive waterjet cutting of titanium alloy Gr2. It is shown that the proper variations of several cutting parameters such as waterjet cutting pressure, cutting speed and cutting depth improve the roughness and characteristics on specimen surfaces produced by AWJ cutting. From the experimental results by AWJ cutting of titanium alloy Gr2, the optimal cutting conditions to improve the surface roughness and precision were proposed and discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.608-611
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• 2002

We developed low resistance drum that is used in sawdust machine in this research. The existent drum have two dimensional cutting form(orthogonal cutting) when see cutting pattern of saw cutter and wood, cutting resistance is big and cutting power is cost much, and also, vibration happens extremely. To improve this shortcoming, we developed helical type low cutting resistance drum for three dimensional cutting possible, decreased vibration and cutting resistance of sawdust machine, and improve productivity and sawdust ventilation. Also, a developed drum is mounting in sawdust machine, it is sold by product.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.206-215
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• 1993

The finite element method is applied to analyze the mechanism of metal cutting, especially micro metal cutting. This paper introduces some effects, such as constitutive deformation laws of workpiece material, friction of tool-chip contact interfaces, tool rake angle and also simulate the cutting process, chip formation and geometry, tool-chip contact, reaction force of tool. Under the usual plane strain assumption, quasi-static analysis were performed with variation of tool-chip interface friction coefficients and tool rake angles. In this analysis, cutting speed, cutting depth set to 8m/sec, 0.02mm, respectively. Some cutting parameters are affected to cutting force, plastic deformation of chip, shear plane angle, chip thickness and tool-chip contact length and reaction forces on tool. Several aspects of the metal cutting process predicted by the finite element analysis provide information about tool shape design and optimal cutting conditions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.132-140
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• 1998

Recently, precision machining technology has been developed continuously in order to make high productivity and quality assurance of the precision parts of several industrial fields. Waviness may occur on the surface of the machined parts due to the table motion error and the dynamic cutting mechanism between the tool and the workpiece. The waviness may fall off the form accuracy of the precision machine parts. In the research, a micro cutting device with piezoelectric actuator has been developed to control precise depth of cut and compensate the waviness on the surface of the workpiece. Experiments have been carried out in the precision lathe. The characteristics of the surface profile and cause of the waviness profile have been analyzed and waviness profiles of some cause have been compared with those of experiments.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.4
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• pp.329-337
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• 2015

In this paper, a simulation based estimation method of energy consumption of the spindle and feed drives for the NC machine tool during the cutting process is proposed. To predict energy consumption of the feed drive system, position, velocity, acceleration and jerk of the table are analyzed based on NC data and then the power and energy are calculated considering friction force and mass of the stages. Energy consumption of the spindle is estimated based on models from acceleration motion of rotating parts, friction torque and power loss of motors. Moreover, simulation models of cutting power and energy for the material removal along the NC tool paths are proposed.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.126-133
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• 2002

The cutting thickness of ultra-precision machining is generally very small, only a few micrometer or even down to the order of a few nanometer. In such case, a basic understanding of the mechanism on the micro-machining process is is necessary to produce a high quality surface. When machining at very small depths of cut, metal flow near a rounded tool edge become important. In this paper a finite element analysis is presented to calculate the stagnation point on the tool edge or critical depth of cut below which no cutting occurs. From the simulation, the effects of the cutting speed on the critical depths of cut were calculated and discussed. Also the transition of the stagnation point according to the increase of the depths of cut was observed.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.57-61
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• 2015

A spindle unit is very important in machine tools. It has a direct effect on machining accuracy. The static and dynamic characteristics of the spindle unit should be considered in the initial design stage for manufacturing of precision product. This study describes an investigation for deriving design stability of a 20,000rpm heavy-cutting spindle for precision machining. Static and dynamic characteristics of the spindle, such as deformation, stress, natural frequency and mode shapes are analyzed using finite element analysis. The 20,000rpm heavy-cutting spindle is confirmed that it is successfully designed through finite element analysis.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.191-197
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• 1993

In this paper, experimental studies are mainly carried out for the evaluation of precision cutting performance of a machine tool spincle running at high speed with the low load, in consideration of the bending vibration characteristics. As a result a process in presented for the practical application in the machine tools industry to evaluate the cutting performance in design stage of spindles.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.39-46
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• 2006

In this work a dynamic cutting force model in ball end milling of inclined surface is introduced. To represent the complex cutting geometry in ball end milling of inclined surface, workpiece is modeled with Z-map method and cutting edges are divided into finite cutting edge elements. As tool rotates and vibrates, a finite cutting edge element makes two triangular sub-patches. Using the number of nodes in workpiece which are in the interior of sub-patches, instant average uncut chip thickness is derived. Instant dynamic cutting forces are computed with the chip thickness and cutting coefficients. The deformation of cutting tool induced by cutting farces is also computed. With iterative computation of these procedures, a dynamic cutting force model is generated. The model is verified with several experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.951-954
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• 2000

This paper presents a new cutting method, i.e. diamond cutting, aided by electrolysis, in order to cut ferrous materials with diamond tools. Diamond cutting is widely applied in manufacturing ultraprecision parts such as magnetic disk, polygon mirror, spherical/non-spherical mirror and copier drum, etc. because of the diamond tool edge sharpness. In general, however, diamond cutting cannot be applied to cutting steels, because diamond tools wear excessively in cutting iron based materials like steel due to their high chemical interaction with iron in high temperature. In order to suppress the diffusion of carbon from the diamond tool and to reduce increase of cutting force due to size effect, we attempt to change chemically the compositions of iron based materials using electrolysis in a limited part which will be soon cut. Through experiments under several micro-machining and electrolysis conditions, cutting using electrolysis, compared to conventional cutting, was found to result in a great decrease of the cutting force, a better surface and much less wear tool.