Surface mounted device rework heat guide
 Leaded and leadless surface mounted devices are removed from or attached to a printed circuit board at various locations, without interfering with or adversely affecting other chips on the printed circuit board. The method of removal involves placing a tool on the substrate, comprising a rigid plate containing a hole, and a hollow tube extending beneath the hole from the rigid plate to the substrate. In this way a surface mounted device to be removed may be surrounded completely by the hollow tube, without encompassing adjacent chips. When heat is directed through the hole in the rigid plate and through the hollow tube to the surface mounted device, the soldered connections attaching the surface mounted device to the board may be melted. A disconnecting means is utilized to remove the surface mounted device from the substrate at the moment the soldered connections are melted or, in the case of non-eutectic solder, changed to a plastic phase. The same tool may be used to facilitate the attachment of a surface mounted device to a printed circuit board, by applying hot gas to the component to be attached, through the hollow tube surrounding that component, as solder is applied to form a plurality of soldered connections. 
B H
B23K H05K
inventional inventional
Harold D. Thomas P. Daren D.
Palmer Mealey Palmer