• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.04b
• /
• pp.389-395
• /
• 1995

The bicycle production process mainly consists of welding process of pipes and its quality is determined by geometrical symmetry of arrangement of welded pipes. Hence, manual quality control of bicycle frames was very ineffecient and required much time in dimensional inspection and does not reserve high precision. In this paper we introduce a method of fast and accurate dimensional inspection of bicycle frame, using the Stereo Vision system and related some image processing techniques.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.624-628
• /
• 1996

Unsteady-state temperature distributions in the high precision spindle system with built-in motor are studied. For the analysis, three dimensional model is built for the high precision spindle. The three dimensional model includes the estimation on the amount of heat generation of bearing and built-in motor and the thermal characteristic values such as heat transfer coefficient. Temperature distributions are computed using the finite element method. Analysis results are compared with the measured data. Analysis shows that temperature distributions of high precision spindle system can be estimated resonably using the three dimensional model through the finite element method.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2010.05a
• /
• pp.1107-1108
• /
• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.10a
• /
• pp.537-538
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.131-134
• /
• 2001

The three-dimensional precision measurement technology for industry product of middle and/or large scale has been developed. Theodolite measurement system which is one of the technology is widely used in aerospace industry. This paper describes measurement method and results for spacecraft structure test model by using the measurement system. And structural stability for STM is desribed through the comparison between design values and measured values.

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

• International Journal of Precision Engineering and Manufacturing
• /
• v.1 no.2
• /
• pp.14-23
• /
• 2000

A numerical scheme is proposed to obtain the individual stress intensity factors in an axisymmetric crack and in a three dimensional mixed mode crack. The method is based on the path independence of J and M integral and mutual or two-state conservation integral , which involves two elastic fields. Some numerical example are presented to investigate the effectiveness and applicability of the method for and axisymmetric crack and a three dimensional penny shaped crack problem under mixed mode.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.407-408
• /
• 2006

Dimensional precision is a critical parameter in net shape processing of ferrous PM components. Sinter-hardening alloys undergo a transformation from austenite to martensite. Martensite formation expands the sintered compact, while tempering hardened steels results in shrinkage. In addition, martensitic regions with high Cu and C contents may contain large amounts of retained austenite. The presence of martensite and retained austenite, in addition to the tempering step, all play a role in the final dimensions of a component. This paper investigates the dimensional and microstructural changes to two sinter-hardening grades through different post-sintering thermal treatments.

• Journal of the Korean Society for Precision Engineering
• /
• v.3 no.1
• /
• pp.60-68
• /
• 1986

Measurement of surface roughness has been done by two dimensional method until now. In recent, three dimensuional method is introduced for the precise measurement of surface roughness. But the study about stylus type three dimensional measurement method is a little. Therefore, in this study, arbitrary machined surface is selected and same part is measured by two dimensional and three dimensional method. The result is that the ratio of tow dimensional to three dimensional value is 0.9-1.1 in Ra. But two dimensional measurement method is underestimated because the ratio is 0.5-0.9 in Rz, Rmax. And it is suitable that the number of measuring line is 100 and y pitch is 5 um by three dimensional surface roughness measuring method.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.7
• /
• pp.1642-1650
• /
• 1995

Process design is one of the most important fields in metal forming, where the finite element method has appeared a useful method for industrial applications. In this study, a program using the rigid plastic finite element has been developed for process design in three-dimensional plastic deformation. The surface integration for calculation of the friction between die and workpiece has been implemented with care in numerical treatment. The developed program is applied to a precision coining process of electronic components. It is confirmed that the program developed here is suitable for process design in metal forming with three-dimensional plastic deformation.