• Why are PCB multilayer boards all even-numbered layers?


Regarding the purchase of multi-layer boards, there is still a lot of knowledge that needs to be possessed. Next, I will continue to share with you. If there are any mistakes, please correct me:
About the number of layers of multilayer boards

Some customers may ask, why are the options all even numbers? Can't you choose an odd number?

For this kind of question, I think many friends have Googled it, and I did the same. However, to be honest, the answer from Google shows that the respondent still does not know enough about the PCB industry.

Theoretically speaking, as long as the number of layers of PCB design data is odd or even within the scope of the process capability, it has no effect on whether the OEM can be manufactured.

However, whether it is online or offline, unless the order is large enough or the customer is willing to pay enough money, PCB foundries are not willing to accept it.

The specific reasons here are very complicated, but the core issues are mainly these three points: cost, time, and quality.
1. Cost
A special design means that it needs to be matched with a special production process to match specific or even completely different production parameters. This requires a lot of trial and error costs. Moreover, if it is not a common process used by the foundry itself, production often requires the designation of experienced engineers to follow up. Moreover, production, process, quality, and planning need to be discussed together and work together, otherwise it is easy to make mistakes... ...

In this way, the cost of the foundry is very high, and reflected in the price, it will be far higher than the price of ordinary designs, which leads to customers often not accepting it and choosing to change the design.

2. time
The special design also means that many places are different. This requires a lot of targeted pre-arrangement to ensure that the PCB is produced according to the data. Obviously, more preparations require more time.

In addition, special designs are often the same as being done for the first time. The workers in the factory are very unskilled, and the production time will be further lengthened.

Therefore, it is possible that the delivery cycle of a 4-layer board with a general design may only take 2 days at the fastest (such as Beton-tech), but a 4-layer board with a special design may take 5 days or even longer.

However, these are not too much, the most difficult thing is the special design, sometimes with the designated special materials. In this case, the materials are not in stock, and the materials need to be bought back first. At this time, if the delivery time exceeds one month, it is extremely normal.

Therefore, if it is not a very high-volume product, under normal circumstances, the foundry can accept it, and the customer cannot accept such a long delivery time. In the end, they choose to give up.

3. Quality
For a special design, if the cost and time can be solved with money and patience, then the quality is not so easy to ensure. No matter how the foundry tries to guarantee it, it is difficult to ensure the yield rate for special processes, and at the same time, it is also difficult to ensure that there are no dead ends in quality control. No matter which foundry it is, the growth of yield and quality requires a relatively long process.

Therefore, for the benchmarks in the consumer electronics industry, such as Huami OV, Apple, Samsung, etc., the development cycle of new products generally requires 6 to 12 months of careful verification. Start mass production to avoid risks that may be unbearable in the future.

However, all of these need to be operated offline, which is difficult to achieve on all current online platforms.

So, to sum up, OEMs don’t like hard work, and customers don’t want to invest too much in certain parts of the product, so an implicit rule has gradually been formed—everyone defaults to using product The layer method is used to produce high-layer boards, and the boards are designed to have even layers, which not only reduces the OEM price, but also facilitates the processing of good products for the first time. Regarding this point, the online setting is an inheritance of the offline tradition.