[ Date Time : 2013-8-23 ] [ Comments : 0
Now a growing number of PCB(printed circuit boards) using surface mount components, compared with the traditional packaging , which can reduce circuit board size, easy-to- volume processing, high density wiring . Chip resistors and capacitors significantly reduce lead inductance in high frequency circuit has significant advantages. Surface mount components inconveniences is not easy to manual welding . Now,STG electronics will show you how to do more easy, for example,common PQFP package chips.
OK,Let's see what are the necessary tools and materials
25W soldering tool requires a small soldering iron copper head , if conditional, with adjustable temperature soldering and ESD protection , soldering iron tip should be sharp, the top width can not exceed 1mm. A pointed forceps can be used mobile and fixed- circuit chips and inspection . Also prepared thin wire and flux , isopropyl alcohol. The main purpose of using the flux is to increase the flow of solder , this copper is easy to track the solder , and rely on the role of surface tension smooth wrapped pin and pad . Clear the board after soldering flux with alcohol .
Ready to welding,
1 . Before welding first to coat the pad with flux with iron handle again, to avoid bad or tin oxide pad , resulting in hard welding, chips are generally not required treatment .
2 . PQFP chip tweezers and carefully place the PCB board , careful not to damage the pin . Its alignment with the pad , to ensure that the chip placed in the right direction . The iron 's temperature is up to 300 degrees Celsius , Then tip tip coated with a small amount of solder,hold down the chip with tools which have been aligned with the right position, the two pairs of angular position of the pin plus a small amount of flux , still to Press and hold the chip , soldering two pairs of angular position on the pin , the chip fixed and not be moved. In the welding finished re- check the chip on the corner position is aligned . If necessary, adjust or remove and re- aligned position in the PCB board .
3 . When all the pins start welding , soldering iron tip should be added to solder all the pins to pin moist Apply flux . Chip with the soldering iron tip contacts the end of each pin , until you see the solder into the pin . To maintain the iron in the welding tip and welded pin parallel , and prevent occurrence of excessive solder lap .
4 . After completing all of the pin welding with flux for wet cleaning solder all pins . Where needed siphoning off excess solder , to eliminate any short-circuit and lap . Finally tweezers to check for Weld, and check is completed, remove flux from circuit boards , will be a hard brush dipped on alcohol wipe carefully in the direction along the pin until the flux disappeared.
5 . Chip RC components are relatively easy to weld , we could have the first point in a solder joint on the tin , then put a device , to clamp the clamping device , after welding on one , and then see if the release is a ; if Put is on the re- welding on the other end . To truly master the welding skills requires a lot of practice .