Soldering and It's Components

Soldering is the process of joining two metals together to form an electrically and mechanically secure bond using heat and a third metal alloy known as solder. 

 

The following is a list of tools for a typical soldering station.
 

1. Variable temperature soldering iron: used for applying heat to joints during the soldering process. 
2. Damp sponge: for cleaning soldering iron tip. 
3. Rosin-core solder: to electrically and mechanically bond a component to the PCB. 
4. Wire cutters or side cutter: for trimming component leads and stripping insulation from wires 
5. Needle nose pliers: for holding, placing and shaping components. 
6. De-soldering pump and/or de-soldering braid: for removing solder. 
7. Scotch tape and/or a “Third Hand”: for securing components. 
8. Safety glasses: for eye protection. These are mandatory in the lab. 
9. Magnifier: to provide more detail during intricate work. A magnifying glass is convenient, but an illuminated magnifier is better. 
10. Light source: to prevent eye-strain. 
11. Ventilation: to extract and dispel fumes generated during the soldering process. 
12. Flux: to clean components and PCB pads. 
13. Acid brush: to assist in the removal of flux residue.

Steps for Soldering:

The following steps will illustrate how to make a proper through hole solder joint on a
PCB

1. Ensure that the printed circuit board and all components are clean. Cleaning can be achieved with a mild abrasive and/or the application of flux. 
2. Plug in the soldering iron, turn it on, and let it warm up for 2-3 minutes. 
3. Wet the soldering station sponge with the water provided in the lab. Do not wet the sponge in the bathroom or the water fountain. 
4. Clean the tip of the soldering iron and tin it with solder. 
5. Insert the component into the holes. Ensure that the component is secure by taping the component or by using a third hand. Optionally, the component leads can be clinched as shown in Fig.5. This technique, however, is not recommended for two sided boards as the flow of solder to the component side is restricted. 
6. Apply the soldering iron tip to one side of joint making contact with the component lead and the board copper foil, ensuring that both are heated up to the same temperature. 
7. Slowly add a few millimeters of solder to the other side of the joint. DO NOT apply solder to the soldering iron tip. If enough heat was applied to the PCB pad and component wire, the solder will flow freely onto the joint. 
8. Remove the solder when the joint is suitably covered. The goal is to get the joint to be a fillet" 
9. If the PCB is double-sided, the solder should flow through the hole around the component lead and make a bond on the component side of the board (opposite to the side that the solder was applied). If this “wicking" does not occur, the hole may be undersized, clinching could be blocking the solder's path, or the component lead is not clean. 
10. Remove the soldering iron and allow the joint to cool naturally. 
11. Cut the lead of the component, if necessary.