1. Iron temperature

SMT tends to work at temperatures similar to hot soldering irons (about 375 ℃), making things faster and requiring fine pitch IC soldering techniques to work. The actual temperature setting will vary for each iron, but it may be between 330 ° C and 626 ° F to 380 ° C/716 ° F (although some inexpensive temperature controlled soldering irons may not have accurate temperature settings if they do not function properly, so try to set them higher). Most modern components have considerable elasticity and are designed to handle automatic soldering and lead-free solder, but even at these higher temperatures, it is best not to leave contact with iron for too long,

2. Welding 0805 chip resistors and capacitors

Apply solder to both pads.

Use tweezers and/or tips to locate the components.

Load some solder onto the soldering iron tip.

At the same time, use a tip to keep the component in place, and touch the soldering iron to one end of the component so that the solder flows to the pad and component end.

Then load some solder onto the soldering iron tip and repeat with the other end of the component (which does not need to be held in place at this time).

The connection checked with a magnifying glass is good, and there are no pads or components near the welding bridge for visual inspection.

3. Welding SOT-23 transistor

Apply solder to all three pads.

Use tweezers and/or tips to locate the components.

Load some solder onto the soldering iron tip.

At the same time, use a tip to keep the component in place, touch the soldering iron to the middle pin/pad so that the solder flows to the pad and pin.

Then repeat this process for the other 2 pins (which will not require this time to hold in place).

The connection checked with a magnifying glass is good, and there are no pads or components near the welding bridge for visual inspection.

4. Welding medium pitch ICs (i.e. 1.27mm pitch SRAM chips)

Apply solder to all pads.

Use tweezers and/or tips to locate the components.

The amount of solder loaded is small enough to solder the tip of the soldering iron.

At the same time, gently fix the component in place and touch the soldering iron to corner pin 1, so that the solder flows to the pad and pin.

Check component alignment.

Weld the pins diagonally in the same way.

Check component alignment again.

Welding each pin, whether by applying very fine soldering iron to each pin or by loading solder and touching the iron of each pin.

If you end the tin bridge between the pins, you can remove it by dragging between the pins or by using some very thin braided soldering iron tips.

Visually inspect the joints with a magnifying glass and, if necessary, remove the welding, weaving, and shorts.

5. Welding fine pitch ICs (i.e. the remaining parts of SMTIC)

Apply a large amount of traffic to all pads.

Use tweezers and/or tips to locate the components.

Load a very small amount of solder onto the soldering iron tip.

At the same time, gently fix the component in place and touch the soldering iron to corner pin 1, so that the solder flows to the pad and pin.

Check component alignment.

Weld the pins diagonally in the same way.

Check component alignment again.

Load a small amount of solder to the soldering iron tip and steadily drag it from one end of the pins to the others. Flux can cause solder to flow to the pins and pads and not bridge.

Repeat the process at these joints when there is not enough solder for the joints.

If you use too much solder, you may end the tin bridge between the pins. These can be removed using some very fine solder braids, or simply by dragging the soldering iron tip along the top of the pin to spread less solder to the pins.

Visually inspect the joints with a magnifying glass and, if necessary, remove the welding, weaving, and shorts.