• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.410-413
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• 1997

Recent general press brake has many problems in cutting high accurate products in the progress of industry. Previous hand-operated press brake needs many pre-processing works to adjust bending angle and marking-off works to calculate bending length. Also, The hand-operating work makes many geometric errors and has difficulty for variety-mass production. To solve these problems, this paper proposes Computer Numerical Control (CNC) general press brake and development of servo-control system based on database for reduction of geometric errors and pre-processing work time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.3
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• pp.13-19
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• 2005

Metal Bearing's research that use the clad steel had led in advanced country. Metal Bearing that is produced by domestic companies is ship, vehicles, development equipment and plant equipment. This is Cast White Metal Lining Bearing that is Bimetal Bearing standing 2 generation. Cast White Metal Lining Bearing is foreseen to be used widely on industry whole in the future. Cast White Metal Bearing is product that need precision processing. But the technique is generalized widely. So an advanced country is depending on import from a developing country that price is cheaper than itself manufacture. it is judged that high added value creation by deepening of price competition is difficult. Therefore need product development of new form and is changing to Trimetal Bearing parts. Trimetal Bearing is high quality technique that do compression junction to thin plates of special object on the Back Metal. Therefore, this research developed Trimetal bearing's materials.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.19-23
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• 2011

Recently, focused ion beam (FIB) applications have been investigated for the modification of VLSI circuit, the MEMS processing, and the localized ion doping, A multi aperture FIB system has been introduced as the demands of FIB applications for high speed and large area processing increase. A liquid metal ion source has problems, a large angular divergence and a metal contamination into a substrate. In this study, a gas ion source was introduced to replace a liquid metal ion source. The gas ion source generated inductively coupled plasma (ICP) in a quartz tube (diameter: 45 mm). Ar gas fed into the quartz was ionized by a 2 turned radio frequency antenna. The Ar ions were extracted by 2 extraction grids. The maximum extraction voltage was 10 kV. A numerical simulation was used to optimize the design of extraction grids and to predict an ion trajectory. As a result, the maximum ion current density was 38 $mA/cm^2$ and the spread of ion energy was 1.6 % for the extraction voltage.

• Design & Manufacturing
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• v.17 no.4
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• pp.14-23
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• 2023

The electric vehicle market is developing rapidly around the world. Also, parts of electric vehicles require precision.In order to produce high-precision motor cores,Press equipment must also have good precision. Drive motor cores are an important technology for electric vehicles. It uses a large high-speed press to mass-produce drive motor cores. Because it's a large high-speed press, there are many reasons why the precision is not good. One of the causes is vibration and noise. Recently, as environmental demands have become stricter, regulations on noise and vibration have been strengthened. It is important for press machines to reduce vibration first for sound insulation and dust proofing. This is because the "breakthrough" phenomenon occurs in the press. Dynamic precision is the precision under the load of the press, Design considering strain and stiffness shall be made. Vibration and noise may occur due to SPM of high-speed press,And vibration and noise can cause structural deformation of the press. Structural deformation of the press can affect the precision of the product.Noise and vibration also cause problems for workers and work environments. Problems with vibration and noise occur during press processing, and vibration and noise lead to damage to the mold or defects in the product. Reliability in high-quality technology must be secured with low noise and low vibration during press processing. Modular shape and deformation energy effects were analyzed through finite element analysis. In this study, a study on vibration and noise countermeasures was conducted through finite element analysis of a large high-speed press.

• Transactions of Materials Processing
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• v.6 no.5
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• pp.408-415
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• 1997

The backward tracing scheme of the finite element analysis, which is counted to be unique and useful for process design in metal forming, has been developed and applied successfully in industry to several metal forming processes. Here the backward tracing scheme is implemented for process design of three-dimensional plastic deformation in metal forming, and it is applied to a precision coining process. The contact problem between the die and workpiece has been treated carefully during backward tracing simulation in three-dimensional deformation. The results confirm that the application of the developed program implemented with backward tracing scheme of the rigid plastic finite element leads to a reasonable initial piercing hole configuration. It is concluded that three-dimensional extension of the scheme appears to be successful for industrial applications.

• The Journal of Korean Medicine
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• v.24 no.2
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• pp.59-65
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• 2003

This study was conducted to analyze metal concentration changes following processing steps for crude, remnant after boiling, and decoction of Korea herbal drugs. We measured meta.! concentration from 20 random patients who visited Oriental medical clinics for treatment of several diseases through normal action. The results obtained were as below: First, in the study to acknowledge quality control between Korean Lab and Harvard Lab in the US, 20 equal herbal samples resulted in the same values, so we confirmed the precision of measurement results from both labs. Second, hazardous metal mean concentration in crude, remnant after boiling, and decoction of herbal drugs were $32.5{\mu\textrm{g}}/22.1{\mu\textrm{g}}/8.8{\mu\textrm{g}}$ for As, $0.0{\mu\textrm{g}}/0.0{\mu\textrm{g}}/0.0{\mu\textrm{g}}$ for Cd, $1.0{\mu\textrm{g}}/0.0{\mu\textrm{g}}/0.0{\mu\textrm{g}}$ for Hg and $5416.3{\mu\textrm{g}}/3639.6{\mu\textrm{g}}/1002.6{\mu\textrm{g}}$ for Pb, respectively. These metal concentrations decreased 72.9-100.0% compared to crude status. The same trend was also visible in the other essential elements. From reviewing these results, we could carefully conclude that decoction had the least amount of metal concentration and is the optimal way to intake herbal drugs.

• Transactions of Materials Processing
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• v.8 no.4
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• pp.384-392
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• 1999

In metal forming, there are problems with recurrent geometric characteristics without explicitly prescibed boundary conditions. In such problems, so-called recurrent boundary conditions must be introduced. In this paper, as a practical application of the proposed method, the precision cold forging of a helical gear has been simulated by a three-dimensional rigid-plastic finite element method and compared with the experiment. The application of recurrent boundary conditions to helical gear forging analysis is proved to be effective and valid. the elastic stress analysis of the die for helical gear forging has been calculated by using the nodal force at the final stage obtained from the rigid-plastic finite element analysis. In order to obtain more precise gear products, the elastic analysis of the die after release of punch and the elastic spring-back analysis of product after ejection have been performed, and the final dimension of the computational product has been in good agreement with that of the experimental product.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.537-542
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• 2004

Machinble Ceramics have some excellent properties as the material for the mechanical components. It is, however, very difficult to grind ceramics with high efficiency because of their high strength, hardness and brittleness. Lapping used diamond slurry and lapping by in-process electrolytic dressing is developed to solve this problem. On this paper, a comparative study of processing ability of lapping used diamond slurry and lapping by in-process electrolytic dressing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.379-382
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• 2007

The MEMS (Micro Electro Mechanical Systems) process is used in a micro/nano pattern manufacturing method. This method is based on the lithography technology. But the MEMS process has some problems such as complicated process, long processing time and high production costs. Many researchers are doing research in substitute manufacturing method to work out a solution to these problems. In this paper, we apply a dieless incremental forming technology to a substitute method of MEMS process. This dieless forming technology is using in the commercial scale sheet forming such as a prototype of automobile sheet parts. 5-axes CNC (Computerized Numeric Control) method are applied in this system to get a micro-scale dieless forming results. These 5-axes system are composed of precision AC servo motor stages (4-axes) and PZT actuator (1-axis). A PZT actuator is used in a precision actuating axis because it can be operated in the nano scale stroke resolution. This micro dieless incremental forming system has the advantage of minimization in manipulating distance and working space. As equipment and tools become smaller in size, minute inertia force and high natural frequency can be obtained. Therefore, high precision forming performance can be obtained. This allows the factory to quickly provide the customer with goods because the manufacturing system and process are reduced. To construct this micro manufacturing system, many technologies are necessary such as high stiffness frame, high precision actuating part, structural analysis, high precision tools and system control. To achieve the optimal forming quality, the micro dieless forming system is designed and made with high stiffness characteristic.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.20-26
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• 2003

This study proposes the construction of attractor quadrant method for high-precision cutting characteristics evaluation of non-ferrous metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of non-ferrous metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to Perform cutting Processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics and attractor quadrant characteristics. In quantitative quadrant feature extraction, 1,309 point in the case of A17075 (one quadrant) and 1,406 point (one quadrant) in the case of brass were proposed on the basis of attractor reconstruction. Proposed attractor quadrant method can be used for high-precision cutting characteristics evaluation of non-ferrous metals.