“At first glance, the PCB looks similar on the surface, regardless of its intrinsic quality. It is through the surface that we see the differences that are critical to the durability and functionality of the PCB throughout its life.

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At first glance, the PCB looks similar on the surface, regardless of its intrinsic quality. It is through the surface that we see the differences that are critical to the durability and functionality of the PCB throughout its life.

It is critical that PCBs have reliable performance, both in the manufacturing assembly process and in actual use. In addition to the associated costs, defects in the assembly process may be carried into the final product by the PCB, which may fail 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 is negligible.

In all market segments, especially those producing products in critical application areas, the consequences of such failures are disastrous.

These aspects should be kept in mind when comparing PCB prices. While reliable, guaranteed, and long-life products have a higher initial cost, they are worthwhile in the long run.

The 14 most important characteristics of high reliability circuit boards

1. 25 micron hole wall copper thickness

benefit

Enhanced reliability, including improved z-axis expansion resistance.

Risk of not doing so

Blow holes or outgassing, electrical connectivity issues during assembly (separation of inner layers, breakage of hole walls), or potential failure under load conditions in actual use. IPCClass2 (the standard adopted by most factories) specifies 20% less copper plating.

2. No welding repair or open circuit repair

benefit

Perfect circuit for reliability and safety, no maintenance, no risk

Risk of not doing so

If not repaired properly, it will cause the circuit board to open circuit. Even if repaired ‘properly’, there is a risk of failure under load conditions (vibration, etc.) that may fail in actual use.

3. Exceed the cleanliness requirements of IPC specifications

benefit

Improved PCB cleanliness improves reliability.

Risk of not doing so

Residues, solder build-up on the board pose a risk to the solder mask, ionic residues can cause corrosion and contamination of the solder surface, which can lead to reliability issues (bad solder joints/electrical failures) and ultimately increase the occurrence of actual failures probability.

4. Strictly control the service life of each surface treatment

benefit

Solderability, reliability, and reduced risk of moisture intrusion

Risk of not doing so

Solderability issues may occur due to metallographic changes in the surface finish of older boards, while moisture intrusion may cause issues such as delamination, inner layer and hole wall separation (open circuit) during assembly and/or actual use .

5. Use internationally renowned substrates C do not use “local” or unknown brands

benefit

Improve reliability and known performance

Risk of not doing so

Poor mechanical properties mean that the board does not perform as expected in the assembled condition, for example: higher expansion properties can lead to delamination, open circuit and warpage problems. Impaired electrical properties can result in poor impedance performance.

6. The tolerance of CCL meets the requirements of IPC4101ClassB/L

benefit

Strict control of dielectric layer thickness can reduce deviations from expected values ​​of 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 may vary greatly.

7. Define solder mask materials to ensure compliance with IPC-SM-840ClassT requirements

benefit

NCAB Group recognizes “good” inks for ink safety, ensuring solder mask inks meet UL standards.

Risk of not doing so

Poor quality inks can cause adhesion, flux resistance and hardness problems. All of these problems can cause the solder mask to detach from the board and eventually lead to corrosion of the copper circuit. Poor insulation properties can cause short circuits due to accidental electrical continuity/arcing.

8. Tolerances defining shapes, holes, and other mechanical features

benefit

Tightly controlled tolerances improve product dimensional quality C Improve fit, form and function

Risk of not doing so

Problems during assembly, such as alignment/mating (problems with press-fit pins are only discovered when assembly is complete). In addition, the mounting into the base can also be problematic due to increased dimensional deviations.

9. NCAB specifies solder mask thickness, although IPC does not

benefit

Improved electrical insulation properties, reduced risk of spalling or loss of adhesion, enhanced resistance to mechanical shock C wherever mechanical shock occurs!

Risk of not doing so

A thin solder mask can cause adhesion, flux resistance and hardness problems. All of these problems can cause the solder mask to detach from the board and eventually lead to corrosion of the copper circuit. Poor insulation properties due to thin solder mask, can cause short circuits due to accidental conduction/arcing.

10. Appearance requirements and repair requirements are defined, although IPC does not

benefit

Safety is created with care and care in the manufacturing process.

Risk of not doing so

Various scratches, minor damage, patching and repairing C circuit boards work but don’t look good. In addition to the problems that can be seen on the surface, what are the unseen risks, the impact on assembly, and the risks in actual use?

11. Requirements for the depth of the plug hole

benefit

High-quality plug holes will reduce the risk of failure during assembly.

Risk of not doing so

Chemical residues from the gold immersion process may remain in holes that are not fully plugged, causing problems such as solderability. In addition, there may also be tin beads hidden in the holes. During assembly or actual use, the tin beads may splash out and cause a short circuit.

12, PetersSD2955 designated peelable blue glue brand and model

benefit

The designation of peelable blue glue avoids the use of “local” or cheap brands.

Risk of not doing so

Inferior or cheap peelables may blister, melt, crack, or set like concrete during assembly, rendering the peelable/ineffective.

13. NCAB implements specific approval and ordering procedures for each purchase order

benefit

The execution of this procedure ensures that all specifications have been confirmed.

Risk of not doing so

If product specifications are not carefully confirmed, the resulting deviations may not be discovered until assembly or final product, when it is too late.

14. Sets with scrapped units are not accepted

benefit

Not using partial assembly can help customers improve efficiency.

Risk of not doing so

Defective kits require special assembly procedures, and it is possible to assemble the known bad board if it is not clear to mark the scrapped unit board (x-out), or to isolate it from the kit. Waste of parts and time.