Many small partners have questions about the advantages and disadvantages of multilayer pcb fabrication.
If we compare a PCB single board and a PCB multilayer board, without discussing their inner quality, we can see the difference through the surface. These differences are important for the durability and functionality of the PCB throughout its service life.The main advantage of PCB multilayers is that these boards are resistant to oxidation. Multiple constructions,PCB factory high densities and surface coating techniques ensure that the boards are of high quality and safe to use. The following are important features of high reliability multilayer boards, that is, the advantages and disadvantages of PCB multilayer boards:.
1, PCB multilayer board hole wall copper thickness for the normal is 25 microns;
Advantages: Improved reliability, including improved Z-axis expansion resistance.
Disadvantages:But there are some risks:In practice, there are problems with blowout or outgassing, electrical connectivity during assembly (inner layer separation, hole wall rupture) or the possibility of failure under load.IPC Class2 (standard for most factories) requires PCB multilayer plating to contain less than 20% copper.
Advantages of fast shipping from Jettop PCB factory:Single-layer double-layer boards can be expedited for 12 hours, four-layer boards can be expedited for 24 hours, six-layer boards can be expedited for 24 hours. Product on-time delivery rate of more than 99%.
2、No soldering technology repair or open circuit protection repair
Advantages: Perfect circuit ensures reliability and safety, no maintenance, no risk.
Disadvantages:PCB multilayer boards are open if not properly maintained. Even if correctly fixed, there may be a risk of failure under load conditions (vibration, etc.). , may lead to failure in actual use.
3. Exceeds the cleanliness requirements of the IPC specification.
Advantages:Improving the cleanliness of multiple layers of PCBs can improve reliability.
Risks: Residues on the terminal board, solder build-up will bring financial risks to the anti-solder layer, ionic residues can lead to our welding surface corrosion and contamination risks, which may affect lead to safety and reliability issues (poor solder joints / electrical equipment failures) and ultimately can increase the probability of failure problems occurring in the actual conduct of the enterprise.
4, strict control of the service life of various surface treatment processes
Benefits: Soldering, reliability and reduced risk of moisture intrusion.
Risks: Surface treatments on older PCB multilayers can lead to metallurgical changes, possible solderability issues, and water intrusion that can cause problems during assembly and/or actual use of the delamination, inner wall to wall separation (openings).
The need for reliable performance of PCB multilayers, both in the manufacturing and assembly process and in actual use, is of course related to the level of equipment and workmanship of the PCB fabricator.
Said the advantages of multilayer boards, to by the way, to answer the students a little doubt, in the PCB circuit boards to order, we live always in the order information page design selection of single, double-sided boards or four-layer boards, but have never seen the three-layer boards? So why did they China did not pass the three-layer board? Come, come, small three main reasons is to tell you PCB why companies have not adopted the three-layer board:
1, the same process
It can be produced in the PCB factory. Generally speaking, the four-layer board core is pressed on both sides of the copper foil, and the three-layer board core is pressed on one side of the copper foil. As far as the process is concerned, stamping is necessary.
2. Same price
The difference between the two processes is that the four-layer board has an additional layer of copper foil and adhesive layer, and the cost difference is not significant. A plate factory offer, generally 3-4 layers of the offer for the first level, to an even number of definition of the offer (of course, there are more than one layer). For example, if you design a five-layer board, the other side will report the price of six-layer board, that is, the price of your design of three-layer board and the price of your design of four-layer board is the same.
3, process stability
In the PCB process, four-layer boards are easier to control than three-layer boards. In terms of symmetry, the warpage of a four-layer board can be controlled below 0.7% (IPC600 standard). However, when the three-layer board size is larger, the warpage will exceed this standard, which will affect the reliability of the SMT and the whole product. Therefore, ordinary designers do not design odd number of layers, even if the function of odd number of layers, will be designed as a pseudo-even number of layers, i.e., 5 layers designed for 6, 7 layers designed for 8.
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