| 摘要 |
The object of this invention was to construct an apparatus for forming solder deposits on a Surface Mount Device (SMD) pad on a printed circuit or hybrid board. This formed solder deposit is in a defined three-dimensional well having the proper profile and a defined solder gap. The solder before forming can be solid solder or a solder paste. By the placement of a mesh on the surface of the circuit board and the application of a slight positive pressure and tension on the mesh with vibration thereof and subjecting this system to a temperature just low enough to reflow the solder by means of a heat transfer fluid either liquid or gaseous, then cooling the board to solidify the solder, a product results having the desirable properties even when block printed. The use of this apparatus eliminates most of the problems of prior art approaches by providing uniform heating at a very short dwell time at temperature in the presence of the mesh. Furthermore, any short circuits originally present in the board or those formed during its processing are subsequently removed during treatment in the apparatus. The duration of the application of heat and pressure is made so brief, that the laminate structure of the board and the coating thereon remain substantially unaffected.
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