1. Cost is higher
At every stage of the manufacturing process, multilayer PCBs are much more expensive than single-layer and double-layer PCBs. What is the purpose of multiple layers in a PCB? What do they need? They are difficult to design and take a lot of time to solve any potential problems. They also require a highly complex manufacturing process to produce, which requires assembly personnel to spend a lot of time and labor.
In addition, due to the nature of these PCBs, any errors in the manufacturing or assembly process are difficult to redo, resulting in additional labor costs or scrap material costs. Most importantly, the equipment used to produce multilayer PCBs is very expensive because it is still a relatively new technology. For all these reasons, unless a small size is absolutely required for the application, in general, the cheaper option may be the better choice.
2. Complex production
The production of multilayer PCBs is more difficult and requires more design time and careful manufacturing techniques than single layer or double layer PCB types. This is because even small defects in PCB design or manufacturing can make it useless.
3. Limited availability
One of the biggest problems with multilayer PCBs is the mechanical cost required to produce multilayer PCBs. Not all PCB manufacturers have the funds or necessity for this equipment, so not all PCB manufacturers have it. This limits the number of PCB manufacturers that can produce multilayer PCBs for customers. Therefore, it is best to carefully ask the PCB manufacturer's ability of manufacturing multi-layer PCB before determining it as a contract manufacturer.
4. Need skilled designer
As mentioned earlier, multi-layer PCBs need to be extensively designed in advance. Without previous experience, this may cause problems. Multilayer boards require interconnections between layers, but they must alleviate crosstalk and impedance issues at the same time. A single problem in the design may cause the circuit board to not work properly.
5. Production time
As the complexity increases, the requirements for manufacturing are getting higher and higher. This has become a key issue for the turnover rate of multilayer PCBs, each board requires a lot of production time, which leads to more labor costs. In addition, this may result in a longer time between placing an order and receiving the product, which may be a problem in some cases.
6. SMT assembly processing
However, these problems will not be reduced by the use of multilayer PCBs. Although they tend to be more costly than single-layer PCBs, multilayer PCBs have more advantages than this type of printed circuit board.