What Is The Best Quality PCB
All PCB board looks almost same from the surface.Through the surface we see differences, and these differences are crucial to the durability and function of the PCB board throughout life.
It is essential that the PCB board have reliable performance both in the manufacturing process and in the actual use.In addition to the relevant costs, the defects in the assembly process may bring into the final product failure during the actual use, resulting in a claim.Therefore, from this point of view, it can be said that the cost of a high quality PCB is negligible.
The application of PCB board involves the fields of automobile, power supply, medical treatment, industrial control, security and even military industry.Like automobile engines, medical equipment, military workers and even aviation equipment, if the PCB board fails on these products, it may endanger human being and state.
These aspects should be keep in mind when compare PCB price,Although the initial cost is higher for reliable, guaranteed and long life products, it is still worth in the long run.
The most important 9 features of a high quality PCB:
1.Copper thickness of hole wall at 25 microns
Benefits: enhance reliability, including improving the ability to resist expansion of the Z axis.
The risk of not doing this: the problem of electrical connectivity (inner separation and hole wall fracture) in the process of blowing holes or degassing or assembling.Or in actual use, there may be a failure under the load condition.
2. No welding repair or circuit repair
Benefits: a perfect circuit ensures reliability and safety, no maintenance, and no risk.
The risk of not doing this: if it is not properly repaired, it will cause circuit open.Even if “proper” is repaired, the risk of failure in the load condition (vibration and so on) may cause a failure in actual use.
3. Cleanliness requirements beyond the IPC specification
Benefits: improving PCB cleanliness can improve reliability.
The risk of not doing this: the residue on the circuit board and the accumulation of solder will bring risk to the welding layer,Ion residues can lead to corrosion and pollution risks of welding surfaces, which may lead to reliability problems (bad solder joints / electrical failures).And ultimately increase the probability of failure.
4. The tolerance of copper clad meets the requirements of IPC4101ClassB/L
Benefits: the strict control of the dielectric thickness can reduce the expected deviation of the electrical performance.
The risk of not doing this: electrical performance may not meet the requirements, and the same batch of components will have a large difference in output / performance.
5. Soldering materials to ensure compliance with IPC-SM-840ClassT requirements
Benefits: ensure the safety of the ink and ensure that the solder layer inks conform to the UL standard.
The risk of not doing this: poor quality ink can lead to adhesion, flux resistance and hardness problems.All these problems will lead to soldering layer peel off from the circuit board and eventually lead to corrosion of the copper circuit.Poor insulation can cause short circuit due to accidental electrical connectedness / arc.
6. Tolerances of shape, hole and other mechanical characteristics
Benefits: strict control of tolerances can improve the quality of the product – the improvement of fit, shape, and function.
The risk of not doing this: problems in the assembly process, such as alignment / coordination (only when the assembly is completed) can be found. In addition, as the size deviation increases, the installation of basement will also be problematic.
7. Thickness of soldering layer
Benefits: improving the electrical insulation characteristics, reducing the risk of peeling or losing adhesion, and strengthening the ability to resist mechanical impact, no matter where the mechanical impact happens.
The risk of not doing this: poor quality ink can lead to adhesion, flux resistance and hardness problems.All these problems will lead to soldering layer peel off from the circuit board and eventually lead to corrosion of the copper circuit.Poor insulation can cause short circuit due to accidental electrical connectedness / arc.
8. Requirements for appearance and repair requirements
Benefits: carefully nurture and carefully cast safety during the manufacturing process.
The risk of not doing this: a variety of bruises, minor injuries, repairs – the circuit board can be used but not good. In addition to the problems that the surface can see, what are the risks that can not be seen, the impact on the assembly, and the risks in actual use?
9. The depth of vias plugged requirement
Benefit: high quality vias plugged will reduce the risk of failure in the assembly process
The risk of not doing this: heavy chemical residue in the vias of uncompleted filling , resulting in solderability problems.But the hole may also be in possession of solder ball, assembly or actual use, solder may splash out, causing a short circuit,also may solder ball hide in vias and splash out when in use causing circuit shot.