• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.3
• /
• pp.218-226
• /
• 2002

This study was carried out to develop continuously variable-speed transmission(CVT) fur an agricultural tractor. The full-toroidal variator mechanism with flour discs and six rollers was utilized as a device fur changing speed ratio continuously. In system layout design, the sizes of the roller cylinders and the end-load cylinder, which were critical factors for controlling the variator, were designed. The planetary gear unit and six pairs of the gear assemblies were designed to establish the maximum speed of the vehicle at 30 ㎞/hr. In addition, the hydraulic clutch, the silent chain, the hydraulic manifold and the electronic controller were designed. Based on the design, a prototype CVT was developed and tested. Test results show that the CVT developed in this study could successfully provide variable speed of the tractor.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.5
• /
• pp.772-778
• /
• 2003

Polystyrene foam is easily melted and vapoured by heat, has a proper quality in the pattern manufacturing and has a low price. The objective of this study is to develop a rapid prototyping method fur polystyrene foam pattern manufacuring to use the eliminative pattern casting (EPC). Applying fur the rapid prototyping concept reversely, the unnecessary part of section is vapored away by heat source of laser beam. In order to examine the applicability between laser beam process and polystyrene foam material, the basic experiments such as hole, line, plane and contour process are carried out. With these results, various three-dimensional shape patterns are made and this rapid prototyping tool for polystyrene foam manufacturing.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.6
• /
• pp.160-165
• /
• 2002

A study on digital processes of injection mold in reverse engineering are presented. Reverse engineering is useful fur several cases, where user has no geometry information of object. Laser scanner is used to obtaining 3D coordinates of object. Sequences to process cloud data are described; sampling to reduce number of points, sorting to adjust the point order, and fitting to curve and surface, and so on. Split slide structure of mold is used fur undercut part and high viscosity material. Flow of injection molding are analysed to correct cooling channel and simulate molding conditions. NC tool paths are generated to carve core and cavity. The processes are performed in digital data for reduction of lead time and consecutive geometry data.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.12 s.177
• /
• pp.117-123
• /
• 2005

This paper deals with the finite element model of the monitor fur the simulation of directional free drop tests such as the backward and vertex free drop as well as the associated free-drop experiment. The model was made for an unconditional stable solution fur the explicit integration algorithm. It was found through the comparison between simulation and experimental results that the general behaviors at the time of impact were observed to well correlate with each other in terms of acceleration, displacement, contact force and stress of monitor components.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.229-232
• /
• 2002

This paper describes the development of robot's finger 3-axis force sensor that detects the Fx, Fy, and Fz simultaneously fur stably grasping an unknown object. In order to safely grasp an unknown object using the robot's fingers, they should detect the force of gripping direction and the force of gravity direction, and perform the force control using the detected farces. The 3-axis force sensor that detects the Fx, Fy, and Fz simultaneously should be used for accurately detecting the weight of an unknown object of gravity direction. Thus, in this paper, robot's finger for stably grasping an unknown object is developed. And, the 3-axis farce sensor that detects the Fx, Fy, and Fz simultaneously fur constructing a robot's finger is newly modeled using several parallel-plate beams, and is fabricated. Also, it is calibrated, and evaluated.

• Journal of Welding and Joining
• /
• v.21 no.4
• /
• pp.63-68
• /
• 2003

Scanning electron microscopy (SEM) has been used as a surface measurement instrument and a tool for lithography in semiconductor process due to its high density localized beam. For those purposes, however, the maximum current of SEM Is less than 100pA, which is not enough fo material processing. In this paper SEM was modified to increase the amount of current reaching a specimen from gun part where current is generated, the possibility of applying SEM to material processing, especially microjoining, was investigated. The maximum current of SEM after modifications was measured up to 10$\mu$A, which is about 10$^{5}$ times greater than before modifications. Through experiments such as eutectic solder wetting on thin 304 stainless steel foil and microjoining of 10$\mu$m thick 304 stainless steel, the intensity of electron beam of SEM proved to be great enough fur material processing as heat source. And a tight jig system was found necessary to hold materials close enough fur successful microloining.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.1
• /
• pp.118-125
• /
• 2003

As consumer's desire becomes various, agility of mold manufacturing is the most important factor for competitive mold manufacturer. Decision making process is required to produce optimal result of CAM systems in using commercial CAM system to generate tool path. The paper proposes a methodology fur computer-assisted tool selection procedures for various cutting type of rough, semi-rough and finish cuts. The procedure provides assistance for machining tool selection by analyzing sliced CAD model section of die cavity and core. Information about machining time for the generated NC-code is used to aid the tool selection. The module is developed with commercial CAM API. This module will be used fur the optimization of tool selection and planning process.

• Journal of the Korean housing association
• /
• v.13 no.3
• /
• pp.85-91
• /
• 2002

The purpose of this study is to find out the effective planning guidelines of elderly housing fur the aged people living with their sons or daughters. To investigate the actual conditions and the problems of housing environments, two hundred and six old people in Gwangiu city, aged over sixty and living with their sons and daughters, were interviewed individually and they provided the useful answers to the questions. The houses for three generations need to have the proper degree of privacy fur each family member, by arranging rooms for their own independent living space while securing the sufficient common space. Therefore, independent and safe living environments are to be made for the elderly and the choice of various types be made according to their own demands. It is also necessary to guarantee the continuation of inhabitation by establishing health care systems and life support services.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.5
• /
• pp.92-98
• /
• 2003

A wind turbine monitoring system is essential equipment fur the performance evaluation and mechanical load analysis of a wind turbine. A monitoring system using LabVIEW is developed in this study. This system monitors signals from a meteorological mast, wind turbine generator, and tower. The discrete signals which are sampled at t Hz are automatically saved on a data file in the unit of a day. Besides these basic functions, the developed monitoring system has the other several capabilities. One of them is the information access from a remote PC through the internet. A vision image of the test site area and data files that are produced by LabVIBW software can be uploaded to the main computer located in a remote site. An emergency backup system using UPS fur the power loss on the monitoring HW is also prepared, A detail explanation for the developed wind turbine monitoring system is presented in this study.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.1
• /
• pp.102-108
• /
• 2003

Recently, the authors have developed a new material test system fur thin film at the high temperature. It is so compact and precise with sub micron resolution that it seems to be a useful tool fur research of the oxide film growth, its mechanical behavior and failure mechanism. To this end. in this paper three methologies are described for in-situ monitoring of the displacement & strain and the temperature, the oxide thickness. These are the Laser Speckle analysis with digital image correlation technique, the two-color infra-red thermometer and the laser reflection interferometry respectively. The calibration results and some issues which should be addressed for practical application are presented.