This invention relates generally to a method for removing components from a printed circuit board and, more particularly, to such method for removing selected surface mounted components without disturbing other components on the board.
Printed circuit boards are used widely in the electronics industry to simplify circuit assembly. Typically, such boards will retain a large number of closely spaced apart surface mounted components. When a given electrical component becomes dysfunctional, it can be economically efficient to replace only the defective component rather than the entire circuit board. However, replacement of a dysfunctional component without damaging that component or other components on the board can be difficult because of their placement in close proximity on the printed circuit board.
The most common technique used for removal of solder mounted components entails the application of heat to melt attaching solder and removal thereof with a vacuum solder "sucker". Problems associated with that technique include the generation of excessive heat, inducing mechanical strain on leads and creation of static electricity, all of which can endanger either the component being removed or adjacent components on the board. Also known are methods in which molten solder is removed by an absorbent wicking material. Examples of the wicking method are disclosed in U.S. Pat. Nos. 4,164,606 and 4,934,582. U.S. Pat. No. 3,210,182 discloses another method in which a solder bath is employed to remove all components from a printed circuit board. All such prior component removal methods have exhibited individual and collective deficiencies including high cost, use difficulty and unreliability.
The object of this invention, therefore, is to provide an improved method for reliably separating defective individual surface mounted electrical components from printed circuit boards.
USPTO Backgrounds
USPTO Backgrounds