• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.433-438
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• 2004

The rapid machining of prototypes plays an important role in product process. Rapid Prototyping(RP) is the widespread technology to produce prototype. But, it have many problems such as shrinkage, deformation and formation occurred by hardening of resin and stair shaping, On the contrary, high speed machining(HSM) technology has many advantages such as good quality, low cost and rapid machining time. Moreover, it is possible to use the material of original product. This paper presents manufacture of trial product by HSM and optimization of machining condition for high productivity in the view of manufacturing time and average error. For example, propeller is machined by the surface machining of thin surface parts. Experiments are designed of machining conditions by Latin Square method and machining condition is optimized and selected by ANOVA

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.73-79
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• 2016

In this paper, the grinding characteristics in thrust internal grinding have been studied using vitreous CBN wheels with a machining center. Grinding experiments have been performed according to grinding conditions such as wheel feed speed, cut depth, workpiece speed, rate of grinding width and number of grinding passes. The machining error, shape of machined surfaces, grinding force, and surface roughness have been investigated though these experiments. Based on the experimental results, the grinding characteristics on the machined surface in the internal thrust grinding are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.34-40
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• 2002

Machining accuracy is affected by quasi-static errors of machining center. Since machine errors have a direct influence upon both the surface finish and geometric shape of the finished workpiece, it is very important to measure the machine errors and to compensate these errors. The laser measurement method for identifying geometric errors of machine tool has the disadvantages such as high cost, long calibration time and usage of volumetric error synthesis model. Accordingly, this paper deals with analysis of the geometric errors of a machine tool using ball bar test without using complicated error synthesis model. Statistical analysis method was adopted in this paper for deriving geometric errors using hemispherical helix ball bar test. As a result of experiment, geometric errors of the vertical machining center are compensated by 88%.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.97-103
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• 2001

Accuracy of a machined part is determined by the relative motion between the cutting tool and the workpiece. One of the important factors which affects the relative motion is the geometric errors of a machine tool. In this study, firstly, geometric errors are measured by laser interferometer, and the positioning error of each control point selected uniformly on the control surface CAD model can be estimated from th oirm shaping model and geometric error data base. Where a form shaping function is derived from the link of homogeneous transformation matrix. Secondly, control points are shifted to the estimated amount of positioning errors. A new control surface is modeled with NURBS(Non Uniform Rational B-Spline) surface approximation to the shifted control points. By generating tool paths to the redesigned control surface, we reduce the machining error quite.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.62-69
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• 2004

This paper presents an experimental study on the dimensional error in ball-end milling. In the 3D free-formed surface machining using ball-end milling, while machining conditions are varied due to the Z component of the feed and existing hemisphere part of the ball-end mill, the mechanics of ball-end milling are complicated. In the finishing, most of cutting is performed the ball part of the cutter and the machined surface are required the high quality. But the dimensional errors in the ball-end milling are inevitably caused by tool deflection, tool wear, thermal effect and machine tool errors and so on. Among these factors, the most significant one of dimensional error is usually known as tool deflection. Tool deflection is related to the instantaneous horizontal cutting force and varied the finishing cutting path. It lead to decrease cutting area, thus resulting cutting forces but the dimensional precision surface could not be obtained. So the machining experiments are conducted fur dimensional error investigation and these results may be used for decrease dimensional errors in practice.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.71-75
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• 2007

Geometrical error of ultra-precision machining due to spherical tool alignment error is analyzed. Deviation of spherical edge, ranged several ten micrometers, generates vertical and horizontal error of tool path and affects profile accuracy of machined surface. Simulation of machined error shows effect of tool alignment error and enables to estimate alignment error. This work provides technical insights into the minimizing of geometrical error of ultra-precision machining.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.172-181
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• 1999

The objective of this research is to develop a measurement error model for sculptured surfaces in On-Machine Measurement (OMM) process based on a closed-loop configuration. The geometric error model of each axis of a vertical CNC Machining center is derived using a 4${\times}$4 homogeneous transformation matrix. The ideal locations of a touch-type probe for the scupltured surface measurement are calculated from the parametric surface representation and X-, Y- directional geometric errors of the machine. Also, the actual coordinates of the probe are calculated by considering the pre-travel variation of a probe and Z-directional geometric errors. Then, the step-by-step measurement error analysis method is suggested based on a closed-loop configuration of the machining center including workpiece and probe errors. The simulation study shows the simplicity and effectiveness of the proposed error modeling strategy.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.126-134
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• 2001

Recently, high productivity and cost reduction becomes the most important target of industries due to the worldwide economic competition. One of these efforts is High Speed Machining(HSM), which reduces machining time with the increase of machining speed such as cutting speed and feedrate. It is very important, especially in case that the portion of machining time in production cost is high. This research suggests optimum cutting conditions to reduce cutting time with minimizing term error. For this study, a comprehensive model representing the texture of machining surface is developed, including rubbing phenomenon on the tip of ball end mill and expanded fibbing zone trajectory caused by tool deflection. Experiments show that the suggested set of feed and pick feed is optimum for maintaining the surface roughness identified by rubbing and low cutting speed in minimum.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.559-560
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.319-320
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• 2010