Author：Peter Pan      

DIP Process is known as dual in line package process which is the combination of electronic components and PCB assembly process in the traditional welding technology. Currently, the new electronic products have been thinner in size and lighter in weight. Most of the DIP components have gradually been replaced by SMD components. The welding assembly method is different with SMT process that is known simply on the components insertion through PTH of PCB by hand, then spray the Flux onto the bottom side of the board by sprayer machine, then board goes through the wave soldering machine via pre-heating and soldering process, melted solder would be wetting on the leads and PTH of PCB for electronic components and PCB-PAD with complete assembly and welding technology.

The following details describes for the DIP process:

Forming Work:

1. Depend on the different components installation type on board that they have to do the forming work by different machine such as IC lead former、lead cutter machine、axial lead forming machine.
2. The purpose of cutting the foot before component insertion is no need to perform cutting operations after welding to avoid solder crack phenomenon.
3. Not easy to install components on conveyer such as Phone Jack and transistor screws on board, those can be done first.
4. Non-wetting of the screw holes and PTH of PCB and SMD components on the bottom side shall be protected by sticking the adhesive tape.

Components Insertion:

1. Insert and install the component through PTH of the board by hand according to every components correct location.
2. Most of current boards are designed double sided and with high density parts that they need to make the carrier for going through wave soldering process. The benefit of carrier is to protect the SMD components on the bottom side and save the time on sticking the adhesive tape. On the other hand it can prevent the board from distortion and the connector parts are in flat contact with the board's surface. This would reduce the probability of repair after the wave soldering process and improve production quality.

Flux Spray:

The functions of spraying the Flux on the bottom side of the board are as follows:

1. To clear the oxide film on the PCB PAD and the metal foot surface of the parts.
2. In the welding surface to form a liquid and protective film to isolate the surrounding air in high temperature and prevent re-oxidation on the metal surface.
3. To reduce the solder's surface tension and increase their spread ability.
4. In the moment of the welding that the molten solder can be readily wet on the component foot and PCB PAD to complete the welding smoothly.

Automatic Wave Soldering:

1. We will do the temperature parameter adjustment on the wave soldering machine at the first production for new product based on the thickness of the board and with or without DIP carrier to keep in SOP as for future production standard.
2. The main function of the pre-heat temperature setting is to reach uniform temperature on board before high temperature welding and bring the Flux's efficiency.
3. The main function of the wave soldering temperature setting is to keep the solder in high temperature and have the better fluidity to complete the welding easily.