PCBA Tech - About the repair of SMT processing components

Chip resistors, capacitors, and inductors are usually called Chip components in SMT. For the rework of Chip components, ordinary anti-static electric soldering iron can be used, or a special clamp-type soldering iron can be used to heat both ends at the same time. Rework of Chip components in SMT is the easiest. Chip components are generally small, so when heating them, the temperature must be controlled properly, otherwise excessively high temperature will damage the components. The soldering iron generally stays on the pad for no more than 3 s during heating. The core of its SMT process flow is: unsoldering and disassembly of chip components, pad cleaning and assembly and soldering of components.

What are the repairs of common components in SMT processing?

1. Desoldering and disassembly of chip components

(1) If there is a coating layer on the component, the coating layer should be removed first, and then the residue on the working surface should be removed.

(2) Install a hot-clamping soldering iron tip with a suitable shape and size in the hot-clamping tool.

(3) Set the temperature of the soldering iron tip to about 300 RON, which can be changed appropriately as needed.

(4) Apply flux to the two solder joints of the chip component.

(5) Use a wet sponge to remove oxides and residues on the tip of the soldering iron.

(6) Place the soldering iron tip on top of the chip component, and clamp the two ends of the component to contact the solder joints.

(7) Lift the component when the solder joints at both ends are completely melted.

(8) Place the removed components in a heat-resistant container.

Implementation steps of the 6

What are the repairs of common components in SMT processing?

2. Pad cleaning

(1) Choose a chisel-shaped soldering iron tip, and set the temperature at about 300 rpm, which can be changed as needed.

(2) Brush the soldering flux on the pads of the circuit board.

(3) Use a wet sponge to remove oxides and residues on the tip of the soldering iron.

(4) Put a soft tin-absorbing braid with good solderability on the pad.

(5) Lightly press the soldering iron tip on the solder-absorbing braid, and when the solder on the pad is melted, slowly move the soldering iron tip and the braid to remove the residual solder on the pad.

What are the repairs of common components in SMT processing?

3. Assembly and welding of chip components

(1) Choose a soldering iron tip with appropriate shape and size.

(2) The temperature of the soldering iron tip is set at about 280 Y, which can be changed appropriately as needed.

(3) Brush flux on the two pads of the circuit board.

(4) Use a wet sponge to remove oxides and residues on the tip of the soldering iron.

(5) Use an electric soldering iron to apply an appropriate amount of solder on a pad.

(6) Use the insert to clamp the chip component, and use an electric soldering iron to connect one end of the component to the soldered pad to fix the component.

(7) Use an electric soldering iron and solder wire to solder the other end of the component to the pad.

(8) Solder the two ends of the component to the pads respectively.