Notch positioning type soldering structure and method for preventing pin deviation

#This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 099119882 filed in Taiwan, R.O.C. on Jun. 18, 2010, the entire contents of which are hereby incorporated by reference.

#The present invention relates to a notch positioning type soldering structure and a method for preventing a pin deviation, in particular to those having at least one notch formed separately on at least two of many solder pads.

#As the electronic industry blooms, electronic devices or products are introduced to the market continuously. To improve the production capacity of the electronic devices or products, manufacturers adopt a surface mount technology (SMT) in related manufacturing processes. With reference to FIGS. 1 to 3 for an exploded view and a perspective view of a conventional electronic component soldered onto a printed circuit board and a top view of a pin, a solder and a solder pad when an electronic component is soldered onto a printed circuit board, the printed circuit board 9 includes a plurality of solder pads 8, and the electronic component 6 includes a plurality of pins 61, wherein the solder pads 8 have a size greater than the size of the pins 61, and the solder 7 is coated onto the solder pads 8. When the electronic component 6 is soldered onto the printed circuit board 9, the pins 61 of the electronic component 6 are inserted into the solder 7 on the solder pads 8, and then the printed circuit board 9 is sent to a soldering furnace to heat and melt the solder 7, and then the temperature of the printed circuit board 9 is dropped to room temperature, such that the solder 7 is solidified to fix the pins 61 of the electronic component 6. However, the melted solder 7 is in a liquid form, and the solder pads 8 have a size greater than the size of the pins 61, such that in the solidification process of the solder 7, the pins 61 of the electronic component 6 will be shifted horizontally on the solder pads 8. After the solder 7 is solidified, the pins 61 of the electronic component 6 are deviated with respect to the solder pads 8 (as shown in FIG. 3). The aforementioned result not only causes problems to the manufacturing processes that follow and reduces the efficiency of the manufacturing processes, but also requires a rework of defectives and increases the manufacturing cost.

#FIG. 1 is an exploded view of a conventional electronic component soldered onto a printed circuit board;

#FIG. 2 is a perspective view of a conventional electronic component soldered onto a printed circuit board;

#FIG. 3 is a top view of a pin, a solder and a solder pad when a conventional electronic component is soldered onto a printed circuit board;

#The objects, characteristics and effects of the present invention will become apparent with the detailed description of the preferred embodiments and the illustration of related drawings as follows.

#With reference to FIGS. 4 to 6 for an exploded view and a perspective view of a first preferred embodiment of the present invention, and a top view of a pin, a solder and a solder pad respectively, the present invention provides a first embodiment of a notch positioning type soldering structure, comprising a plurality of solder pads 3 installed on a printed circuit board 5 for connecting a SMT electronic component 1 having a plurality of pins 11, and the solder pads 3 have a size greater than the size of the pins 11, and the quantity of pins 11 can be two or more, and three pins 11 are shown in the figures for illustrating the embodiment of the invention, and the quantity of solder pads 3 corresponds to the quantity of pins 11. The notch positioning type soldering structure of the present invention is characterized in that each solder pad 3 is disposed in an alignment direction 4 of the printed circuit board 5, wherein each of at least two solder pads 3 includes at least one notch 31, the at least two solder pads 3 can be leftmost and rightmost solder pads 3, two left solder pads 3, two right solder pads or three solder pads 3. In the figures, the leftmost and rightmost solder pads 3 are adopted for illustrating the invention, and the quantity of notches 31 can be one or more, and one notch 31 is shown in the figures for illustrating the invention, and the notch 31 is disposed in an area corresponding to the external periphery of the pin 11 during the soldering process and provided for aligning edges of the pins 11 to limit a displacement of the pins 11.

#If it is necessary to solder the pins 11 of the electronic component 1 onto the printed circuit board 5, the solder pads 3 is coated with a solder 2 first, wherein a moldboard (not shown in the figure) having a plurality of penetrating holes (not shown in the figure) is covered onto the printed circuit board 5, and the penetrating holes are disposed at positions corresponding to the positions of the solder pads 3, and the shape and size of the penetrating holes are the same as those of the solder pads 3, and then a solder such as a solder paste is coated onto the penetrating holes. After the moldboard is removed, a solder 2 is coated onto the solder pads 3, and the shape and size of the solder 2 are the same as those of the solder pads 3, and a notch 21 is formed, and then the pins 11 of the electronic component 1 are inserted into the solder 2 on the solder pads 3, and then the printed circuit board 5 is sent into a soldering furnace (not shown in the figure) to heat and melt the solder 2, and then allow the temperature of the printed circuit board 1 to drop back to room temperature, such that the solder 2 is solidified gradually. During the solidification process of the solder 2, the notches 31 of the solder pads 3 do not have any solder, so that towards the notches 31. In other words, the notches 31 limit the positions of the pins 11 of the electronic component 1, such that during the solidification process of the solder 2, the pins 11 of the electronic component 1 will not be shifted with respect to the solder pads 3. Until the solidification of the solder 2 completes, the pins 11 of the electronic component 1 on the solder pads 3 will not be deviated.