• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.11-18
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• 2011

A worm screw is widely used in a geared motor unit for motion conversion from rotation to linear. For mass production of a high quality worm, the current rolling process is substituted with the milling process. Since the milling process enables the integration of all operations of worm manufacturing on a CNC(Computer Numerical Control) lathe, productivity can be remarkably improved. In this study, the tooling system for side milling on a CNC lathe to improve machinability is developed. However, the cutting tool-workpiece interference is important factors to be considered for producing high quality worms. For adaptability of various worms machining, the tool-workpiece interference simulation system based on a tool-tip trajectory model is developed. The developed simulation system is verified through several kinds of worms and experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.97-104
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• 2006

ELID(Electrolytic In-process Dressing) grinding is an excellent technique for mirror grinding of various advanced metallic or nonmetallic materials. A polishing process is also required for elimination of scratches present on ELID grinded surfaces. MAP(Magnetic Assisted Polishing) has been used as polishing method due to its high polishing efficiency and to its resulting in a superior surface quality. This study is describing an effective fabrication method combining ELID and MAP of nano-precision mirror grinding for glass-lens molding mould. It also presents some techniques for achieving the nanometer roughness of the hard metals, such as WC-Co, which are extensively used in precision tooling material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.623-624
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• 2005

Micro injection molding is a branch of micro system technology and has been under development for the mass manufacture of micro parts. Enhanced technological products like micro optical devices are entering the market. This paper presents fundamental research on the injection molding technique in micro fabrication. In order to successful manufacturing of micro plastic parts, it is necessary to research for development of micro-injection machine, machining of micro mold, decision of optimum injection conditions and the research for polymer material. Therefore in this study, in order to machining of micro mold, a mold core with microscopic V-shaped groove was tooled by ultra-precise tooling machine. The transcription experiments with a polymer, PMMA resin on the surface of core with Ni plating were carried out and surface profile of injected parts was measured with AFM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.430-433
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• 2005

Laser bonding between similar and dissimilar thermoplastics has been investigated by making use of laser transmission weld technique. Spot welding of two layers of plastic materials has been demonstrated by using of a high-quality diode-laser with 808nm wavelength. Weld areas increases according to power density, exposure time. The results of peel out test show that peel strengths increase with the area of molten plastics. Layers, which have the same chemical properties, have good bonding qualities. A bonding method which dye film is coated on the interface is used for laser bonding between plastics with high transmission for laser wavelength. Laser transmission bonding is worthy of attention because it is not in contact, requires a few tooling devices, allows a flexible energy delivery and produces nearly invisible welds

• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.96-102
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• 2000

The finishing process for dies and molds is an important process because it has influence on final quality of products. And it is difficult to automatize finishing process so that the process has depended on expert's skill until now. However, recently a study on development of die automatic finishing machine has been progressed, and actually this machine is applied to fabrication of die. But the research about tooling system is not enough and finishing tool must have high machining efficiency and adaptability of curved surface. So, this study investigated the application of conductive elastic tool which is composed of metal-resin bonded pellet and elastic backing material. The metal-resin bonded pellet is used to finish the surface by conventional mechanical grinding or electro-chemial grinding method. And elastic backing material is used to follow the curved surface. So conductive elastic tool has long lifetime, uniform removal rate and adaptability of curved surface.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.185-189
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• 2001

In order to prevent the production defects the optimum design of product, jig and fixture putting in the field is very significant manufacturing method. Drilling Jig is the device according to industrial demand for multi manufacturing products on the growing at alarming rate. In the field of design and making for machine tool working, welding, assembling with jig and fixture for mass production is a specific division. They require analysis of many kinds of important factors, theory and practice of machine tool operating process and jig & fixture structure, machining condition for tool making, tool materials, heat treatment of jig & fixture components, know-how and so on. In this study we designed and constructed a drilling jig of mass production and performed tryout under the Auto CAD, Auto Lisp database, that we made by database, and window environment. Especially this study is reveals with the analysis of part drawing, jig planning, jig design etc, and then the result of drill jig's making try out.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1243-1248
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• 2007

In recent, rapid manufacturing (RM) technology is widely used to develop an injection mould with a high performance. The objective of this paper is to develop the injection mould with a high productivity using a hybrid RM technology combining Laser-aided Direct Metal Tooling process with a machining process. The geometry decomposition has been utilized to improve the speed of the manufacturing for the mould. Mould with conformal cooling channels has been designed to improve cooling characteristics. Several experiments have been carried out to evaluate characteristics of the mould manufactured from the hybrid RM technology. In addition, injection molding tests have been performed to examine the performance of the manufactured mould. The results of the injection molding tests have been shown that a cooling time and the injection time of the designed mould are reduced to one-fifth and one-second that of the mould with convention cooling channels.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.300-304
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• 1993

Chip formation control is an important problem in the automation of manufacturing process, since the continuous chip can cause catastrophic failures of the tooling and entangle the workpiece causing damage. However, it is impossible to predict chip form correctly due to the complex nature of cutting process. In order to detect the chip form for unmanned manufacturing, a new identification method is proposed. The feasibility of using acoustic emission signals from the sensing plate for identification of chip form is investigated. Experiments were conducted under the various cutting conditions. When the acoustic emission sensor is attached to the sensing plate, it turns out that the moving averaged AE signals correlated well with the collision of segmented chips with the plate. The sensitivity of moving averaged AE signals to chip congestions due to continuous chip formation is illustrated as well.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.148-155
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• 2001

Hydraulic breaker is currently used for many civil engineering areas owing to the ease of changing the tooling mechanism. However, due to a high noise level, it has been one of notorious sources of environmental noise and the prevailing environmental concerns force the manufacturers to reduce the radiated noise levee during operations. To comply with such concerns, the present study is focused on designing and developing a low-noise hydraulic breaker For this purpose, sound sources are identified and relative contributions are rated. Acoustic enclosure. sealing systems, and low-nolle type chisel have been developed and applied to the actual machine. As a result, the radiated noise from the developed low-noose hydraulic breaker is reduced more than 13 dB(A) In comparison with the conventional hydraulic bleaker.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.163-172
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• 1994

The Aerospace and automobile industries have need to avoid sheet-metal forming problem such as incorrect springback after forming and trimming process, excessive thinning/tearing, wrinking/perkering. It is common practice to use costly trial-and-error experimental methods to develop tooling and manufacturing process parameters. Experimentation should be complemented with computer simulation to reduce cost and leadtime in manufacturing and to influence the design of components. In this study, firstly we solved the springback problem after drawing and trimming process of KFP(F100-229) engine airsealing bearing support part(53H00) forming and studied on the effect of several process parameters on the gap between the formed blank and punch shape using the implicit F.E.M code(ABAQUS). Secondly by the three dimensional dynamic analysis using the explicit. F. E. M code (LS-DYNA3D), we studied on the effect of several process parameters which can be used for avoid tearing and wrinking during the drawing process.