1. MSL classification awareness and management
Each moisture-sensitive component is classified into different levels (MSL) according to its moisture sensitivity. This standard defines in detail the maximum exposure time and re-feeding interval of the component. For example:
MSL level 1: below 30°C/85%RH, enjoy unlimited workshop life.
MSL levels 2 to 6: gradually shortened to 12 hours of workshop life (level 6 needs to be baked before use), all need to be stored in an environment below 30°C/60%RH.
Having a clear understanding of the MSL level of moisture-sensitive components and strictly storing, using and feeding according to its requirements is the basis for avoiding welding defects and improving product quality.
2. Application of professional moisture-proof cabinets
PCBA processing plants should use moisture-proof cabinets with precise temperature and humidity control functions to store moisture-sensitive components to ensure that the ambient humidity is maintained below 10%RH.
The temperature and humidity alarm should be installed on the moisture-proof cabinet to monitor and warn of excessive humidity in real time to ensure the stability of the storage environment.
3. Humidity label card system
Implement strict humidity label card management. Each time you take a component, you need to check the label status and record the time of taking and returning to the box, so as to promptly find and deal with damp components.
4. Standardization of baking treatment
Baking is a key step to remove moisture from components and prevent welding quality problems.
It is necessary to set appropriate baking conditions (such as 125°C) according to the component type and exposure time to ensure that moisture is completely removed. For components that have not been used for a period of time or have been exposed for too long, they must be baked before they can be put online.
5. MSL determination and verification process
To ensure the quality of moisture-sensitive components, a comprehensive MSL determination process must be implemented, including initial and final inspections, intermediate processing and other steps.
Confirm the initial state of the component through SAT testing, and perform SAT testing again after completing humidification and reflow soldering tests to verify the packaging quality.
6. Operation records and material traceability
PCBA processing plants should formulate strict forms and require operators to strictly register before each pick-up, inspection and feeding.
These records are not only an important basis for material traceability, but also key data support for evaluating management effects and optimizing management processes.
