PCB Technical - 10 characteristics of pcb circuit board

10 characteristics of PCB, PCB circuit boards are almost the same on the surface regardless of their internal quality.

It is through the surface that we see the differences, and these differences are critical to the durability and function of the PCB circuit board throughout its life.

Whether in the manufacturing assembly process or in actual use, PCB circuit boards must have reliable performance, which is very important.

In addition to related costs, defects in the assembly process may be brought into the final product by the PCB circuit board, and failures may occur during actual use, leading to claims.

Therefore, from this point of view, it is no exaggeration to say that the cost of a high-quality PCB circuit board is negligible.

In all market segments, especially the markets that produce products in key application areas, the consequences of such failures are unimaginable.

When comparing PCB prices, these aspects should be kept in mind. Although the initial cost of reliable, guaranteed, and long-life products is high, they are still worth the money in the long run.

Let’s take a look at the 14 most important features of high-reliability PCB circuit boards:

1, 25 micron hole wall copper thickness benefits: enhanced reliability, including improved z-axis expansion resistance.

The risk of not doing this: blow holes or outgassing, electrical connectivity problems during assembly (inner layer separation, hole wall breakage), or failure under load conditions during actual use. IPCClass2 (the standard adopted by most factories) requires 20% less copper plating.

2. No welding repair or open circuit patching repair benefits: a perfect circuit can ensure reliability and safety, no maintenance, no risk.

The risk of not doing this: If the repair is not done properly, it will cause the circuit board to break. Even if the repair is ‘proper’, there is a risk of failure under load conditions (vibration, etc.), which may cause failure in actual use.

3. Cleanliness requirements beyond IPC specifications Benefits: Improve PCB cleanliness to improve reliability.

Risks of not doing so: Residues and solder accumulation on the circuit board bring risks to the solder mask. Ionic residues can cause corrosion and contamination risks on the soldering surface, which may lead to reliability problems (bad solder joints/electrical failures), and Eventually increase the probability of actual failure.

4. Use internationally renowned substrates-do not use "local" or unknown brands Benefits: Improve reliability and known performance

Risk of not doing this: Poor mechanical performance means that the circuit board cannot perform the expected performance under assembly conditions, for example: high expansion performance will cause delamination, disconnection and warping problems. Weakened electrical characteristics can lead to poor impedance performance.

5. Strictly control the service life of each surface treatment. Benefits: solderability, reliability, and reduce the risk of moisture intrusion

The risk of not doing this: due to the metallographic changes in the surface treatment of the old circuit boards, soldering problems may occur, and moisture intrusion may cause delamination, inner layers and hole walls during the assembly process and/or actual use Separation (open circuit) and other issues.

6. The tolerance of the copper clad laminate meets the requirements of IPC4101ClassB/L. Benefits: Strictly controlling the thickness of the dielectric layer can reduce the deviation of the expected electrical performance.

Risk of not doing so: The electrical performance may not meet the specified requirements, and the output/performance of the same batch of components will be quite different.

7. Define solder mask materials to ensure compliance with IPC-SM-840ClassT requirements. Benefits: NCAB Group recognizes "excellent" inks, achieves ink safety, and ensures that solder mask inks meet UL standards.

The risk of not doing this: Inferior ink can cause adhesion, flux resistance and hardness problems. All these problems will cause the solder mask to separate from the circuit board and eventually lead to corrosion of the copper circuit. Poor insulation properties can cause short circuits due to accidental electrical continuity/arc.

8. Defining the tolerances of shapes, holes and other mechanical features Benefits: Strict control of tolerances can improve the dimensional quality of products-improve fit, shape and function

Risk of not doing this: problems in the assembly process, such as alignment/fitting (only when the assembly is completed will the press-fit pin problem be discovered). In addition, due to the increased size deviation, there will be problems when installing the base.

9. NCAB specifies the thickness of the solder mask, although IPC does not have relevant regulations. Benefits: Improve electrical insulation properties, reduce the risk of peeling or loss of adhesion, and strengthen the ability to resist mechanical impact-no matter where the mechanical impact occurs!

Risk of not doing this: Thin PCB solder mask can cause adhesion, flux resistance and hardness problems. All these problems will cause the solder mask to separate from the circuit board and eventually lead to corrosion of the copper circuit. Poor insulation properties due to the thin solder mask can cause short circuits due to accidental conduction/arc.

10. Defined appearance requirements and repair requirements, although IPC did not define the benefits: careful care and carefulness in the manufacturing process to create safety.