| 摘要 |
Screen printing apparatus including two cameras for effecting alignment of a stencil with a PCB or circuit board (20). The circuit board (20) is mounted on a table (12) movable relative to a stencil (26) fixed in position on the apparatus. The table is able to move in a first direction between a circuit board loading position and a print position. A first camera (11) for viewing the circuit board (20) is mounted on the apparatus for movement in a direction transverse to the first direction. A second camera (13) for viewing the stencil (26) is mounted on the table (12) and is mounted for movement in a direction perpendicular to the first direction. Thus each camera (11,13) is effectively able to move in X any Y axes relative to the object (20,26) it views. By means of viewing fiducial marks on the circuit board (20) and the stencil (26) with the cameras as the table (12) moves from the load position to the print position, a control unit of the apparatus ascertains the relative positions of the circuit board (20) and the stencil (26), aligns the stencil and circuit board and then prints solder paste onto the circuit board (20) in a pattern determined by the stencil (26).
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