PCB Circuit Board Welding Technology

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In the PCB manufacturing process, welding is a crucial step. It not only secures the components to the PCB board but also ensures that the solder joints are firm and smooth. The quality of welding techniques directly impacts the success of PCB production, making soldering skills essential for every PCB manufacturer. Below are the main points regarding welding:

### 1. Welding Methods

Components must be clean and tinned before welding. Electronic components, when stored in the air, can develop an oxide film on their pins due to oxidation, along with other contaminants. Before welding, this oxide film can be removed using a knife, after which a layer of solder (commonly referred to as "tin") should be applied. This preparation makes the component easier to weld and reduces the likelihood of poor solder joints.

### 2. Welding Temperature and Time

When welding, the temperature of the soldering iron should be higher than that of the solder, but it should not be excessively high—this is indicated by the rosin beginning to smoke. If the welding time is too short, the temperature at the solder joint may be too low, leading to insufficient melting of the solder. This can result in rough solder joints and the risk of cold solder joints. Conversely, if the welding time is too long, the solder may flow excessively, which can overheat and damage the components.

### 3. Positioning of the Soldering Iron and Welding Points

To enhance heat transfer and improve welding speed, the surface of the soldering iron should make good contact with the welding point.

### 4. Post-Welding Inspection

After welding, it is essential to check for any missed solder joints, cold solder joints, or short circuits caused by solder flow. A common method to check for cold solder joints is to gently pull on the component pin with tweezers; if you notice any movement, immediate repair is necessary.

PCB Circuit Board Welding Technology

### The Weldability of PCB Circuit Boards

PCB circuit boards serve as the support structure for electronic components and provide electrical connections between them. Depending on the number of circuit layers, they can be classified as single-sided, double-sided, or multi-layer boards. Common multi-layer boards typically have four to six layers, and more complex designs can have over ten layers.

To ensure that a printed board achieves a relatively long shelf life and maintains a good wetting effect with solder, proper solderability treatments are required on the surface. The ability of a metal surface to be wetted by molten solder is referred to as solderability. This is a complex issue; therefore, solderability treatment is necessary for the surface of printed boards.

Freshly manufactured printed boards, particularly those with a copper surface, are prone to absorbing dust, moisture, and various airborne gases due to their high surface tension. Improper handling can lead to contamination from sweat and oil, while oxygen in the air can create metal oxides (CuO), which reduce the copper surface's wettability.

### Three States of Solder After Melting on Metal Surfaces:

1. **Non-Wetting:** When molten solder does not adhere to the metal surface and exposes the base metal, this is known as non-wetting. This indicates poor weldability of the metal.

2. **Wetting:** When molten solder forms a uniform, smooth, and non-breaking thin layer on the metal surface, it is called wetting. This indicates that the metal has good weldability.

3. **Semi-Wetting:** When molten solder forms irregular bumps on the metal surface without exposing the base metal, it is referred to as semi-wetting. This indicates that the weldability of the metal is subpar.

After drilling the printed circuit and creating the circuit pattern and shape, treatments must be applied to improve the weldability of the printed circuit and to prevent or delay the degradation of the pad’s solderability.

Why Choose China PCBA Supplier KSPCBA as Your PCB Circuit Board Welding Technology Manufacturer?

– Experienced and skilled team

– State-of-the-art equipment

– Strict quality control

– Excellent customer service

– Competitive price