An air cooling system using an axial flow fan is generally applied in an electronic cabinet on shipboard. However, cases that apply a water cooling system or a mixture of water cooling and an air cooling system are gradually increased by applying the high-performance SBC (Single Board Computer) or DSP (Digital Signal Process), which has a high heating value. In this study, a structure borne noise reduction design for an electronic cabinet that applied a mixture of air and water cooling system was performed. First, the cooling system design was performed using a numerical analysis to secure a thermal stability, and then an electronic cabinet was produced. Next, considering the cooling performance, the reduction design for structure borne noise that causes an underwater radiated noise was performed using the experimental approach. The electronic cabinet, which has a thermal stability and meets the structure borne noise specifications, was finally developed.

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP processes were developed with an eye to mass production of precision optical glass parts by molding press. Generally, because the forming stage in a GMP process is operated at high temperature above 570℃, thermal stresses and deformations are generated in the aspheric glass lens mold that is used in GMP process. Thermal stresses and deformations have negative influences on the quality of a glass lens and mold, especially the height of the deformed glass lens will be different from the height of designed glass lens. To prevent the problems of a glass lens mold and the glass lens, it is very important that the thermal stresses and deformations of a glass lens mold at high forming temperature are considered at the glass molds design step. In this study, as a fundamental study to develop the molds used in an aspheric glass lens fabrication, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally, using analysis results, it was predicted the height of thermally deformed guide ring and calculated the height of the guide ring to be modified, 64.5 ㎛. This result was referred to design the glass lens molds for GMP process in production field.

Recently, remarkable progress has been made in both technology and production of optical elements including aspheric lens. Especially, requirements for machining glass materials have been increasing in terms of limitation on using environment, flexibility of material selection and surface accuracy. In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP process was developed with an eye to mass production of precision optical glass parts by molding press. This GMP process can produce with precision and good repeatability special form lenses such as camera, video camera, aspheric lens for laser pickup, f-B lens for laser printer and prism, and fine glass parts including diffraction grating and V-grooved base. GMP process consist a succession of heating, forming, and cooling stage. In this study, as a fundamental study to develop molds for GMP used in fabrication of glass lens, we conducted a glass lens forming simulation. In prior to, to determine flow characteristics and coefficient of friction, a compression test and a compression forming simulation for PBK40, which is a material of glass lens, were conducted. Finally, using flow stress functions and coefficient of friction, a glass lens forming simulation was conducted.