Hand Soldering Tips For Surface Mount Components

First, the tools and materials needed

The soldering tool requires a 25W copper tip soldering iron. A condition welding station with adjustable temperature and ESD protection is required. Please note that the tip should be thin and the top width should not exceed 1 mm. A pointed tweezers can be used to move and fix the chip and check the circuit. Also prepare fine lines and flux, isopropyl alcohol, etc. The purpose of using the flux is mainly to increase the flowability of the solder so that the solder can be pulled by the soldering iron and smoothly wound around the pin and the pad by the action of the surface. Remove the flux from the plate with alcohol after soldering.


Second, the welding method

1. Prior to soldering, the flux is applied to the pads and treated with a soldering iron to prevent the pads from being tinned or oxidized, resulting in poor soldering. The chip usually does not need to be processed.

2. Carefully place the PQFP chip on the PCB with tweezers, taking care not to damage the pins. Align it with the pad to ensure that the chip is placed in the correct orientation. Adjust the temperature of the soldering iron to above 300 degrees Celsius, apply a small amount of solder on the soldering iron tip, press the chip to the aligned position with a tool, and add a small amount of stitches at the opposite corners of the solder. Hold the chip and solder the pins at two diagonal positions to secure the chip without moving. After soldering the diagonal, recheck the position of the chip. Adjust or remove and realign the position on the PCB if necessary.

3. When soldering all pins, the solder should be applied to the soldering iron tip and all pins should be soldered together to keep the pins wet. Touch the end of each pin of the chip with a soldering iron tip until you see solder flowing into the pins. Keep the tip parallel to the solder leads during the soldering process to prevent overlap due to over soldering.

4. After soldering all leads, wet all pins with solder to clean the solder. Remove excess solder where needed to eliminate any shorts and overlaps. Finally, check the solder joints with tweezers. After the inspection is complete, remove the flux from the plate, dip the hard brush with alcohol, and carefully wipe along the wire until the flux disappears.

5. Chip RC components are relatively easy to solder. You can place the tin on the solder joint first, then place it on one end of the component, clamp the component with tweezers, and solder it to see if it is correct. If you are right, you will weld another one. Mastering welding techniques requires a lot of practice.