While most circuit boards are rigid in nature, their primary purpose is to facilitate the flow of current, which relies on delicate alignments within the board. Consequently, both during production and usage, circuit boards are susceptible to moisture-related threats. To enhance their reliability, designers and manufacturers must develop strategies for protecting PCB from moisture. In this section, TechSparks provides a comprehensive overview of the moisture resistance specifications outlined by IPC to assist readers in understanding standard moisture levels.
PCB moisture levels refer to the ability of the circuit to withstand different humidity environments while maintaining proper electrical performance. International standards, such as those defined by IPC, provide designers with guidelines in this regard. IPC has classified PCB moisture levels into four categories: IPC-6012A-1, IPC-6012A-2, IPC-6012A-3, and IPC-6012A-4. These specifications serve as acceptance documents, establishing clear indicators for addressing humidity-related concerns.
- IPC-6012A-1: PCB meeting this standard can function in environments with less than 30% humidity without experiencing a loss in electrical performance. Such boards do not require special moisture protection, and manufacturers need to primarily focus on humidity control during the production process.
- IPC-6012A-2: This category does not specify the maximum humidity tolerance or humidity test methods for PCB. Instead, it emphasizes that manufacturers should follow appropriate processes and best practices, such as employing dry production processes, utilizing dry cabinets for storage, and similar measures.
- IPC-6012A-3: Designed for environments with a maximum humidity level of 80%, this category mandates the use of fiber materials that meet the specified humidity requirements. Additional protective measures, such as the use of desiccants, sealed packaging, or moisture-controlled environments during the final stages of manufacturing, are necessary to safeguard the PCB from the adverse effects of humidity.
- IPC-6012A-4: Suitable for environments where humidity exceeds 80%, this category requires manufacturers to implement comprehensive protective measures for PCB.
The PCB moisture level is of utmost importance as it determines the stability and reliability of the board in various environments. Therefore, when selecting a protection strategy, it is crucial to assess the specific circumstances and choose the appropriate moisture level. Implementing suitable moisture control measures ensures the normal operation of the circuit.