• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.295-299
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• 2022

In this paper, paint-free metallic plastic material, polypropylene (PP) and acrylonitrile styrene acrylate (ASA) materials were investigated on the applications for bumper skid plate and outside mirror housing parts. In order to maximize metallic effect, type, size and content of aluminum pigment were optimized based on flop index. Hybrid aluminum pigments with different aspect ratios were used to conceal weld lines. By controlling the fluidity of the material, the flow mark problem, generated on the surface of the part, was resolved. We also investigated the surface defects of flow and weld lines by using the developed modeling and simulation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.139-144
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• 2011

This paper presents a boundary element application to determine the optimal impressed current densities at defect position on the pipe line. In this protection paint, enough current must be impressed to lower the potential distribution on the metal surface to the critical values. The optimal impressed current densities are determined in order to minimize the power supply for protection. This inverse problem was formulated by employing the boundary element method. Since the system of linear equations obtained was ill-conditioned, including singular value decomposition, conjugate gradient method were applied and the accuracies of these estimation. Several numerical examples are presented to demonstrate the practical applicability of the proposed method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.183-188
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• 2012

This study was carried out to design the spray nozzle tip for airless spray coating. Airless spray coating is the process of coating an object with a liquid spray of paint or other fluid. The nozzle tip controls the fluid flow rate and creates back pressure in the system. The nozzle tip also defines the spray pattern by the size and shape of the orifice. The spray pattern of nozzle tip was investigated numerically using ANSYS CFX ver. 14.0. It was observed that performance result of designed nozzle tip was correspond well, compared with that of GARCO nozzle tip.

• Tuberculosis and Respiratory Diseases
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• v.65 no.6
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• pp.541-545
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• 2008

Hypersensitivity pneumonitis (HP) is an immunologically-mediated disease resulting from repeated exposure to sensitizing agents, such as organic dusts or chemicals. Isocyanate is a volatile and highly reactive chemical that is extensively used in the manufacturing of automobiles, upholstery, and polyurethane foam. Occupational respiratory diseases associated with isocyanate, such as bronchial asthma, are well-known. It is thought that HP is one of the rare diseases induced by isocyanate with a very low frequency worldwide. We report a case of HP in an automobile painting sprayer which appeared to be associated with isocyanate.

• Journal of Conservation Science
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• v.37 no.6
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• pp.701-711
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• 2021

This study identifies the structure and material characteristics of the mural paintings in Daeungjeon at Ssanggyesa temple in Jindo by conducting scientific research and analysis including microscope examination, SEM-EDS, XRD, particle size analysis, and others. According to the analyses, the murals were considered to be of a typical soil mural style for Korean Buddhist murals, given that the walls were made of sand and soil and the murals had layers consisting of wall layers and a finishing layer. However, some finishing layer used calcite, while some ground layer used zinc white beneath the thick paint. In addition, there were similar features to those found on the surfaces of oil paintings such as cracks along with the paint layer, high gloss on surfaces, and thick brush strokes in many areas. It was found that the walls on which the murals were painted were made of soil but that the paint layer was created based on the oil painting technique using drying oil. It determined that the murals were painted in a unique painting style that is rarely found in other typical Buddhist murals in Korea.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.35-41
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• 2023

In this study, silicon sludge generated in semiconductor manufacturing process is recycled and applied as materials for pigments and paints. In detail, metallic impurities are removed from silicon sludge to obtain plate-like silicon sludge powder (SW-sludge), which is then coated with titanium dioxide via sol-gel method (TCS-sludge). SW-sludge and TCS-sludge are dispersed in hydrophilic transparent varnish and sprayed onto glass substrates to observe the possibility for the application as materials for pigments and paints. Notably, the applicability of TCS-sludge-based paint is improved compared to SW-sludge-based paint after the titanium dioxide coating. Moreover, the color of TCS-sludge-based paint turns into white. Accordingly, it is confirmed that the applicability and hydrophilicity are improved by the presence of outer titanium dioxide layer. In this regard, it is expected that the recycled TCS-sludge may be a future material for the application as pigments and paints.

• Journal of Welding and Joining
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• v.34 no.1
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• pp.21-25
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• 2016

The automotive vehicle is made through the following processes such as press shop, welding shop, paint shop, and general assembly. Among them, the most important process to determine the quality of the car body is the welding process. Generally, more than 400 pressed panels are welded to make BIW (Body In White) by using the RSW (Resistance Spot Welding) and GMAW (Gas Metal Arc Welding). Recently, as the needs of light-weight material due to the $CO_2$ emission issue and fuel efficiency, new joining technologies for aluminum, CFRP (Carbon Fiber Reinforced Plastic) and etc. are needed. Aluminum parts are assembled by the spot welding, clinching, and SPR (Self Piercing Rivet) and friction stir welding process. Structural adhesive boning is another main joining method for light-weight materials. For example, one piece aluminum shock absorber housing part is made by die casting process and is assembled with conventional steel part by SPR and adhesive bond. Another way to reduce the amount of the car body weight is to use AHSS (Advanced High Strength Steel) panel including hot stamping boron alloyed steel. As the new materials are introduced to car body joining, productivity and quality have become more critical. Productivity improvement technology and adaptive welding control are essential technology for the future manufacturing environment.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.191-198
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• 2016

Traceability is essential in modern automotive manufacturing. Among existing technologies, RFID is the most promising choice for this purpose. However, due to the harsh conditions of production lines, especially in the paint shop, automobile OEMs would require expensive dedicated RFID tags and readers, which are incompatible with standard RFID technologies. Unlike the manufacturing industry, the logistics industry uses UHF label tags for track and trace, which provides high performance and a low price. Recently, this technology has improved to the extent that it can be used in harsh conditions such as on metal parts or in liquid. Herein, we assess the technical, operational, and economic feasibility of UHF label-tag technology for seamless end-toend traceability. Based on prototyping, lab/field tests, and cost-benefit analysis, we have proven that the single disposable UHF tags can successfully replace the problematic and expensive tags used in most domestic automobile OEMs today.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.714-719
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• 2011

The surface roughness depending on the machining method is very important because is produce a finished product through riveting, sealing, bonding, and special paint in order to curb the turbulence and air resistance which occur between the sheets. Aluminum alloy 2024 which is widely used for interior and exterior material of aircraft are tested. Jin-young JW-60C wire cutting machine was used in this experiment. In this paper, the experimental investigation has been performed to find out the influence of the surface roughness and surface shape characteristics on the wire-cut EDM of discharge energy in aluminium alloy 2024. The selected experimental parameters are peak current, no-load voltage, off time and feed rate. The experimental results give the guideline for selecting reasonable machining parameters. The high discharge energy on the idle time, almost no change in surface roughness can be seen.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.609-615
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• 2021

Chemical accidents can happen anywhere in the world. To prevent chemical accidents, Korea introduced the Chemicals Control Act. However, Small and medium-sized businesses do not meet these regulations. Accordingly, the Ministry of Environment is providing a chemical safety management support project for Small and medium-sized businesses. However, there are many small and medium-sized businesses, and businesses that need support need priority. In this study, the risk of the plants was classified into hig h, medium, and low risk based on four methods. As a result, out of 90 plants subject to the study, high risk was 30% and medium risk was 70%. The industries with the high risk were chemical products manufacturing and paint manufacturing. The plating and printing industries showed relatively medium risk. This risk classification has the advantage that it can obtain intuitive and quick results. These studies can be used as basic data for chemical safety management of local governments and Ministry of Environment.