PCB News - Analysis of the repair process in the PCB board production process

Analysis of the repair process in the PCB board production process

In the PCB production process, rework is an inconspicuous but very important process. Many high-quality and defective PCB boards have gained a "new life" through rework in this production process and become products with qualified quality. Today we will explain the rework process in the PCB board production process for you in detail.

1. The purpose of PCB repair

1. In the reflow soldering and wave soldering processes, the defects such as open circuit, bridging, false soldering and poor wetting, need to be repaired manually with the help of certain tools to achieve the effect of removing various solder joint defects, so as to obtain qualified The solder joints of the PCB board.

2. Repair the missing components.

3. Replace the components that are pasted in the wrong position or damaged.

4. After debugging the single board and the whole machine, replace inappropriate components.

5. The PCB board should be repaired if any problems are found after leaving the factory.

Second, determine the solder joints that need to be repaired

1. Positioning electronic products

To determine what kind of solder joints need to be repaired, you should first locate the electronic product and determine which level of product the electronic product belongs to. Level 3 is the highest requirement. If the product belongs to Level 3, it must be tested according to the highest standard; if the product belongs to Level 1, it is sufficient to follow the lowest standard.

2. It is necessary to clarify the definition of "good solder joints".

Good solder joints refer to solder joints that can maintain electrical performance and mechanical strength during the design of electronic products, considering the use environment, method and life cycle; as long as this condition is met, there is no need to rework.

3. Measure with IPCA610E standard. It does not need to be repaired if the conditions of acceptable level 1 and 2 are met.

4. Use the IPC-A610E standard for inspection, and the defects of level 1, 2, and 3 must be repaired.

5. Use IPCA610E standard for testing, process warning level 1 and 2 must be repaired.

Note: Process warning 3 means that although there are conditions that do not meet the requirements, it can still be used safely. Therefore, in general, process warning level 3 can be treated as acceptable level 1, and repairs are not required.

Three, rework matters needing attention

1. Don't damage the pad

2. Ensure the usability of the components. If it is a double-sided welding component, one component needs to be heated twice; if it is repaired once before leaving the factory, it needs to be heated twice; if it is repaired once after leaving the factory, it needs to be heated again twice. Based on this calculation, a component must be able to withstand 6 times of high-temperature soldering to be considered a qualified product. For high-reliability products, perhaps components that have been repaired once can no longer be used, otherwise reliability problems will occur.

3. The component surface and PCB surface must be kept flat.

4. The process parameters in production should be simulated as much as possible.

5. Pay attention to the number of potential electrostatic discharge hazards, and perform the operation according to the correct welding curve when repairing.

The above is the rework process in the PCB board production process explained by the editor. I hope it will be helpful to you.