A
Available hand soldering methods are indicated on the following chart.
| Method |
Applicable |
| Soldering iron |
× |
| Spot heater |
○ |
Hand soldering differs from the reflow soldering method since soldering is performed through localized rapid heating on arbitrary parts. At this time, there will be a distinctive temperature change and residual stress, so please take note of the 2 points below.
- Mitigate thermal shock to chips by preheating chips to prevent damage (cracking) to parts through localized rapid heating and thermal shock.
- Since the board temperature is lower compared to when reflowing, a difference in residual stress occurs during cooling, and machine strength (board bending strength) will become more likely to decline. To increase that strength, it is required to maintain the board temperature at a high temperature when soldering.
Soldering method using the spot heater
Place paste solder on the board land.
Then, place a chip on the solder applied land.
Finally, apply the spot heater and solder.
You can suppress cracks without preheating chips by soldering using hot air.
Furthermore, by applying hot air on the board when soldering, you will be able to raise the board temperature when soldering.
Soldering conditions when using spot heaters
- Distance between parts and nozzle: 5 mm or more
- Application angle: 45°
- Nozzle outlet air temperature: 400°C or less
- Flow amount: set to the minimum value
- Nozzle bore diameter: 2 mmΦ
- Application time (common for all products): within 10 sec