Reflow Solder

Reflow Solder

A typical Printed Circuit Board, or PCB, contains a large number of electronic components. These components

are bonded to the copper pads on the board through a process called soldering. Soldering can either be done

through a soldering iron or by melting the solder flux in an oven. The latter process is called reflow soldering.

This method is mainly used to solder Surface Mount Devices, or SMDs, on a PCB. The main advantage of reflow

soldering is that it makes it possible to solder a large number of components at the same time.

Instructions

1.Place the PCB on a flat, dry surface with the component side facing up.

2.Identify the pads on the PCB where components are to be soldered. Apply a small amount of solder flux paste

on each of these pads by positioning the dispenser nozzle on top of the pad and gently squeezing the bottle.

Be careful not to dispense too much solder, since the excess may flow to nearby pads and create shorts.

3.Hold one of the components to be soldered with tweezers and place it on the board so that its terminals are

aligned with their corresponding PCB pads. Slightly push the component down so that the sticky solder flux

paste holds it in place. Repeat this process to place the remaining components on the board.

4.Put the safety glasses on. Place the board in the reflow oven and set its peak temperature.

The peak temperature can be found on the solder flux paste container. Generally, it is between 220 and 260

degrees Celsius, but can be significantly higher for lead-free solder pastes. Most reflow ovens have a knob on

the front panel to set the peak temperature. Once the temperature has been set, turn the oven on. Leave the

board inside the oven until the process is over. Most reflow ovens have a buzzer sound or a green light on

the front panel to indicate that the process is complete. Wait for another 15 minutes before taking the board

out of the oven. Use gloves to handle the board, since it may still be fairly hot.