• Design & Manufacturing
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• v.18 no.1
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• pp.39-45
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• 2024

The radiator grille has several air intakes. These holes cause the resin flows to divide and merge. As a result, weld lines occur. These weld lines and other problems appear in various forms depending on the grille pattern. To solve these problems, designers use injection molding analysis to proactively identify problems and determine optimal molding conditions. In this study, we conducted research on the effect and optimization of gates on injection molding of automobile radiator grille. The gates used in molding analysis are the side gate and the grape gate. We then compared the effects of each gate on weld line, injection pressure, clamping force, and deflection. As a result of the analysis applying the side gate, weld lines occurred in all major grilles. In contrast, in applying the grape gate, small weld lines occurred in the minor grille, but the weld line in the major grille could be prevented. The maximum injection pressure was reduced by 48.2% in applying the grape gate compared to applying the side gate. Additionally, the maximum clamping force was also reduced by 17.6%. To compare the amount of deformation, deflection values were measured at 20 identical locations. As a result, applying the grape gate showed a deformation improvement of at least 5.2% and up to 77.9%.

• The Korean Journal of Pesticide Science
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• v.7 no.4
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• pp.258-263
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• 2003

In order to get the actual pesticide usage data for fruit crops at farmer's gate, this survey was carried out on the growers of 6 representative fruit crops such as apple, citrus, grape, peach, pear and persimmon, in Korea. One hundred fifty farmers were selected in main production areas to record their pesticide usage during the growing seasons. Pesticides were sprayed in pear 15.2 times/year and persimmon 7 times/year. Pesticide input amount per unit for fruits was 39.5 for citrus, 22.1 for apple, 21.5 for pear, 11.9 for peach, 10.8 for persimmon and 6.7 a.i. kg/ha for grape, respectively. The amounts of pesticides sprayed in 2002 except for peach and pear tend to decrease compared with those in 1999. The major fungicides used were mancozeb, propineb, dithianon, etc., while the major insecticides were fenitrothion, chlorpyrifos, methidathion, etc. Total active ingredients of pesticides used for six fruit crops amounted to 18.3% of total sales amount of pesticides for horticulture in 2002. The amounts of pesticides sprayed on citrus, grape, peach and pear in Korea was less than those in U.S.A., excepting those in apple.