PCB News - Steps and technical requirements of manual welding in smt factory

Steps and technical requirements of manual welding in smt factory
In the PCB production process of the smt factory, we will have some relatively small orders or repair orders; then at this time, engineers will generally let us use manual welding. When it comes to manual welding, what are the basic requirements for welding? Let's talk to you about the steps and technical requirements of manual welding in the smt factory.
1. The role of manual welding in smt factory

Welding components and wires to make them reliably connected, with good electrical conductivity and certain mechanical strength, and the original weldments can also be decomposed.

Two, the basic essentials of welding in smt factory

1. Clean metal surface is the prerequisite to ensure good welding.

2. The best welding temperature is reached when heating.

3. Have a certain welding time (the welding speed should be appropriate).

4. Solder should have good wetting ability in liquid state (flux can be used).

Third, the quality requirements of the solder joints of the smt factory

Good electrical contact; good mechanical properties; beautiful appearance. Strictly prevent false welding and repair welding. The solder joints should not be too large. They should be shiny and beautiful, but firmness is the first priority.

Note: Welding technology is not only related to the level of labor productivity and production cost of the whole machine assembly, but also the key to the quality of electronic products. To achieve that each solder joint is not only uniform and beautiful, but also has good electrical properties and mechanical strength, it cannot be mastered overnight. A person engaged in electronic technology work, especially a beginner, must earnestly learn the theoretical knowledge of welding. Master the essentials of welding technology and be able to perform welding operations proficiently, so as to ensure welding quality and improve work efficiency.

Four, the basic steps of smt factory welding

1. Hold the soldering iron in your right hand. Use needle-nose pliers or tweezers to hold the component or wire with your left hand. Before soldering, the soldering iron should be fully preheated. To eat tin on the edge of the soldering iron tip, bring a certain amount of solder.

2. Put the blade surface of the soldering iron head close to the solder joint, and heat the soldered surface to the temperature at which the solder melts. The electric soldering iron forms an angle of about 60°C with the horizontal so that the molten tin flows from the tip of the soldering iron to the solder joints, and the solder is melted and filled on the surface of the metal to be soldered. The time that the soldering iron tip stays at the solder joint is controlled within 2 to 3 seconds.

3. Raise the tip of the soldering iron when the tin material and flow toughness on the solder joint are appropriate. The left hand still holds the component. After the tin at the solder joint has cooled and solidified, the left hand can be released.

4. Rotate the lead with tweezers to confirm that it is not loose, and then cut off the excess lead with pliers.

Five, the basic technical requirements of welding quality

1. The solder joints should be firm and have a certain strength;

2. There should be no false welding, false welding, missing welding, etc.;

3. There should be no overlap welding, butt welding, bridging, tin splashing, etc. between the solder joints;

4. The solder joints should not have burrs, voids, trachoma, pores, etc.;

5. The solder joints should be bright and uniform in size;

6. The surface of the solder joints should be clean and free of flux residue;

7. The solder materials on the solder joints should be adapted;

8. Master the welding temperature to prevent the wires and components from being burnt.
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