As an important component of electronic devices, the rework process of PCBA needs to strictly follow a series of technical specifications and operational requirements to ensure the quality of rework and the stability of the equipment. This article will discuss in detail the key points to note during PCBA rework from multiple aspects, hoping to be helpful to everyone.
- Requirements for baking
During the rework process of PCBA boards, baking treatment is of great significance.
Firstly, for the new components to be installed, according to their sensitivity levels in the supermarket and storage conditions, they must undergo baking and dehumidification treatment in accordance with the relevant requirements in the “Specification for the Use of Moisture-Sensitive Components”, which can effectively remove the moisture in the components and avoid problems such as cracks and blistering during the welding process;
Secondly, if the rework process requires heating above 110℃, or if there are other damp-sensitive components around the rework area, it is also necessary to perform a drying treatment to remove moisture in accordance with the specification requirements. This can prevent the components from being damaged by high temperatures and ensure the smooth progress of the rework process.
Finally, for the damp-sensitive components that need to be reused after rework, if the rework process adopts the rework techniques such as hot air circulation or infrared heating of solder joints, a drying treatment to remove moisture is also required. If the rework process adopts the rework technique of heating solder joints with a hand soldering iron, and the heating process is controlled, the pre-drying treatment step can be omitted.
- Requirements for Storage Environment
After baking treatment, components and PCBAs that are sensitive to moisture also need to pay attention to the storage environment. If the storage conditions exceed the time limit, these components and PCBAs must be re-baked to ensure good performance and stability during use.
Therefore, during the rework process, it is necessary to closely monitor the temperature and humidity parameters of the storage environment to ensure compliance with the specification requirements. At the same time, regular inspections of baking should be conducted to prevent potential quality problems.
- Requirements for the number of rework heating cycles
According to the specification requirements, the cumulative number of rework heating for components should not exceed 4 times. The allowable rework heating times for new components should not exceed 5 times, while the allowable rework heating times for re-used components that have been removed should not exceed 3 times.
These restrictions are put in place to ensure that components and PCBA boards do not suffer excessive damage during multiple heating processes, thereby affecting their performance and reliability. Therefore, the number of rework heating times must be strictly controlled during the rework process. Meanwhile, for components and PCBA boards that are close to or have exceeded the heating times limit, their quality conditions need to be carefully evaluated to avoid using them in critical positions or high-reliability equipment.