• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.59-64
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• 2008

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in tooling system of high speed spindle. This paper concerns the static stiffness in the main spindle interface according to variation of clamping force, rotational speed and tool holder shank. Finite element analysis is performed by using a commercial code ANSYS workbench. From the results, it has been shown that the geometry of tool holder shank is mostly influence on the variation of the static stiffness in the main spindle interface.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.6
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• pp.19-25
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• 2019

We have developed a tool that uses finite element analysis (FEA) to rapidly evaluate a shaft-bearing system of machine tools. We extracted commercial data on suitable clamping units and defined the inner profile of the shaft to avoid needing direct user input to define the profile. We use a splitting algorithm to convert the shaft into beam elements with two diameters and length. To validate the tool, we used it to design and evaluate a shaft-bearing system and found that our tool automated the construction of an FE system model in a commercial FEA package as well as the static stiffness evaluation; both tasks were completed in seconds, demonstrating a significant reduction from the minutes normally required to complete these tasks manually.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.180-186
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• 1996

Using carbon steel or ceramic as a shaft material of monolithic and slited insert ring clamped on it. The fitting strengths of the sgrink fitted assemblies measured from room temperature to 30$0^{\circ}C$ and following conclusions were obtained as results of this investigation. 1) The fitting condition under which the shrink fitted assemble was stronger than that using simple fit in high temperature. 2) When both material of the 30mm-diameter shaft and 55mm-diameter boss are SM45C the clamping torque is increased 2.7times as the interference increases 3 times from 20${\mu}{\textrm}{m}$ at the contact length of 6mm monolithic fit. 3) When only the material of boss is changed to STS 304 the clamping torque is increased at the rate of 37.3N.m per 1mm increase of the contact length at the interference of 50${\mu}{\textrm}{m}$ monolithic fit.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.104-108
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• 2000

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. In order to prevent the production defects the optimum design of product, fig and fixture putting in the field is very significant manufacturing method. They require analysis of many kinds of important factors, theory and practice of machine tool operating process and its phenomena, 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, database, and window environment. Especially Part1 of this study is reveals with the analysis of part drawing, jig planning, jig design etc.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.33-37
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• 2000

Milling fixture is one kind of machining device according to the industrial demands for multi manufacturing products on the growing at alarming rate. In the field of design and making for machine tool working, welding, assembling with fixture for mass production is a specific division. In order to prevent the production defects, occurring, the optimum design of product, fixture putting in the field is very significant manufacturing method. They require analysis of many kinds of important factors, theory and practice of machine tool operating process and its situations, fixture and its structure, machining condition for tool making tool materials, heat treatment of fixture components, know-how and so on. In this study we designed and constructed a milling fixture of mass production and performed tryout under the AUTO CAD, database, I-DEAS and WINDOW environment. Especially part 1 of this study is reveals with the analysis of part drawing, fixture planning, fixture design etc.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.3
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• pp.1-7
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• 2006

By the reason of increased demand of high productivity, the researches on manufacturing process and equipments for reducing cycle time have been made in many directions of a machine tool industries. Especially high productivity is very important to machining center with high-speed spindle. This paper proposed method of reducing T-T(tool to tool) time which results in shorter unclamping time. T-T time varies as factors such as a hydraulic system, a drawbar mass, a flow meter, a disc spring, piston and pipe diameters. In this paper We could find design factors has much influence on decreasing the unclamping time using DOE(Design of Experiment) and optimized the level of the factors using AMESim $4.0^{(R)}$ and visualNastran $4D^{(R)}$ Finally, we have verified improved result of the optimized factors with initial design.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.99-104
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• 2004

Micro/meso cutting is getting more important in the fields of precision machining technology. A micro-turning lathe is one of parts to consist the Micro Factory. It accepts stepwise motion actuators that are used for feeding system instead of the conventional mechanism. It is consisted of two Piezoelectric ceramics; one is for feeding the slider, and the other is for clamping the slider in the guide way of the body. The linearity and positional accuracy of the actuators are good enough for high precision motion. The spindle unit is operated with DC motor on the top of the slider. The motion is communicated with miniaturized linear encoder attached on each side of axis. A mono crystal diamond tool is used for cutting tool. This micro-lathe has been made a machining experiment to see the characteristics of micro-machining.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.452-457
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• 2003

As a fundamental study on developing elements with micro shape, micro mold parts machining and experiment of injection molding using it were performed. The ultra precision micro machining system with high functionality was fabricated, and utilized in the machining of micro parts. By using this machining system and micro end-mill tool, a micro circle column structure of high aspect ratio, diameter 60 $\mu\textrm{m}$, height 500 $\mu\textrm{m}$, was fabricated. And a micro lens molds were fabricated by using ball end-mill tool of 300 $\mu\textrm{m}$ diameter and diamond fly-cut tool of 150 $\mu\textrm{m}$ radius. A micro injection molding machine, which is clamping force 1.75 ton, injection capacity 2.8cc, was fabricated for injection molding experiment using micro molds. The injection molding experiment was performed by using the injection molding machine, micro cylinder structures and lens molds. This paper introduces these micro machining system and injection molding machine and demonstrates examples of injection molding using fabricated molds.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.484-487
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• 2003

In designing AMBs (active magnetic bearings) for high-speed spindle system, the shaft is usually assumed as a rigid rotor. For automatic tool change process, there should be a tool clamping system with drawbar using spring or hydraulic force, and the drawbar in the spindle can be in various condition of support during design and manufacturing error. In this paper, the modal characteristics of drawbar in high-speed milling spindle system due to supporting stiffness between drawbar and shaft are analyzed by numerical method. The result shows enough stiff supports must be provided between shaft and drawbar to prevent occurring drawbar vibration lower than the natural frequency of 1$\^$st/ bending mode of spindle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1745-1748
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• 2005

According to the demand of the high productivity, the interest of manufacturing skills is growing in industrial society. Especially the high speed spindle in machining center becomes important these days. The exchange time of the tool in machining center usually calls T-T(tool to tool) time. Detailly explaning, It is influenced by the unclamping time. Affecting factors of the unclamping time are various(the hydraulic system, drawbar mass, a flow meter, disc spring, a piston diameter, pipe diameters, and so on). In this study, we could find factors that decrease the unclamping time and verify it for softwares.(AMESim $4.0^{(R)}$ & visual Nastran $4D^{(R)}$)