Precision PCB Fabrication, High-Frequency PCB, High-Speed PCB, Standard PCB, Multilayer PCB and PCB Assembly.
The most reliable PCB & PCBA custom service factory.
At first glance, regardless of the inherent quality of the PCB, it looks the same on the surface. It is through the surface that we see the differences, and these differences are critical to the durability and functionality of the PCB throughout its life.
Whether in the PCBA manufacturing assembly process or in actual use, PCB 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, and malfunctions 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 is negligible.
In all market segments, especially the markets where products in key application areas are produced, 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.
High-reliability circuit boards should have the following 14 most important characteristics:
1. The copper thickness of the hole wall of 25 microns
benefit:
Enhance reliability, including improving the expansion resistance of the z-axis.
Risk of not doing this:
Blowing holes or outgassing, electrical connectivity problems during assembly (inner layer separation, hole wall breakage), or failure under load conditions in actual use. IPCClass2 (the standard adopted by most PCB factories) requires 20% less copper plating.
2. No welding repair or open circuit repair
benefit:
Perfect circuit can ensure reliability and safety, no maintenance, no risk
Risk of not doing this:
If repaired improperly, the circuit board will be broken. 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
benefit:
Improving PCB cleanliness can increase reliability.
Risk of not doing this:
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 ultimately increase the occurrence of actual failures. Probability.
Fourth, strictly control the service life of each surface treatment
benefit:
Solderability, reliability, and reduce the risk of moisture intrusion
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 problems such as delamination, separation (open circuit) of the inner layer and the hole wall during the assembly process and/or actual use. .
5. Use internationally well-known substrates-do not use "local" or unknown brands
benefit:
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 warpage problems. Weakened electrical characteristics can lead to poor impedance performance.
6. Tolerance of copper clad laminate meets IPC4101ClassB/L requirements
benefit:
Strictly controlling the thickness of the dielectric layer can reduce the deviation of the expected electrical performance.
Risk of not doing this:
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
benefit:
NCAB Group recognizes "excellent" inks, realizes ink safety, and ensures that solder mask inks meet UL standards.
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 PCB 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
benefit:
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, the press-fit pin problem will be discovered). In addition, due to the increased size deviation, there will be problems when installing the base.
Nine, NCAB specifies the thickness of the solder mask, although IPC does not have relevant regulations
benefit:
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. Appearance requirements and repair requirements are defined, although IPC does not define
benefit:
In the manufacturing process, we take care and make it safe.
Risk of not doing this:
Various scratches, minor damages, repairs and repairs-the circuit board works but doesn't look good. In addition to the problems that can be seen on the surface, what are the invisible 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 the assembly process.
Risk of not doing this:
The chemical residue in the gold deposit process can remain in the hole that is not full of the plug hole, which can cause problems such as solderability. In addition, there may 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 specifies the brand and model of peelable blue glue
benefit:
The designation of peelable blue glue can avoid the use of "local" or cheap brands.
Risk of not doing this:
Inferior or cheap peelable glue may foam, melt, crack or solidify like concrete during the assembly process, so that the peelable glue cannot be peeled off/doesn't work.
13. NCAB implements specific approval and ordering procedures for each purchase order
benefit:
The execution of this program can ensure that all specifications have been confirmed.
Risk of not doing this:
If the product specifications are not carefully confirmed, the deviation may not be discovered until the PCB assembly or the final product, and it will be too late at this time.
14. Do not accept boards with scrapped units
benefit:
Do not use partial assembly can help customers improve efficiency.
Risk of not doing this:
All defective boards require special assembly procedures. If it is not clear to mark the scrap unit board (x-out), or if it is not isolated from the board, it is possible to assemble this known bad board. Waste parts and time.
