| 摘要 |
An apparatus and method for temporarily sealing holes in printed circuit boards are disclosed. The apparatus comprises two major assemblies: a heater block assembly and a vacuum table assembly. The heater block assembly employs a temperature controlled, insulated heater block having a surrounding, movable vacuum collar. A flexible thermally conductive vacuum skin is mounted on the movable vacuum collar and forms a vacuum chamber in cooperation with a movable vacuum table having a flat, porous plate whose upper surface is parallel to the vacuum table surface. A sandwich comprising a porous release sheet, the printed circuit board, a thermodeformable material and a thermally conductive cover sheet is positioned on the vacuum table flat, porous plate. Thereafter, the vacuum table and sandwich are moved together so that the table forms a sealing relation with the flexible, thermally conductive vacuum skin. A vacuum is then drawn in the now formed vacuum chamber forcing the flexible, thermally conductive vacuum skin against the sandwich to compress the porous release sheet between the printed circuit board and the flat, porous plate. At this point, the flexible, thermally conductive vacuum skin, sandwich and vacuum table are moved into a position in which the flexible, thermally conductive vacuum skin is formed into thermally conductive contact with the heater block. Heat from the heater block softens the thermodeformable material so that it deforms into the holes of the printed circuit board forming protectively sealing plugs therein. After cooling, the vacuum table is moved in the reverse direction to permit removal of the sandwich.
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