PCB Technical - PCB board cost and PCB board bending degree

If PCB routing does not require additional layers, why use it? Does the reduction layer make the circuit board thinner? If the circuit board is one less layer, will the PCB cost be lower?

However, in some cases, adding layers will reduce costs.

PCB boards have two different structures: core structure and foil structure. In the core structure, all conductive layers in the PCB board are applied to the core material, while in the foil structure, only the inner conductive layer of the PCB board is applied to the core material, and the outer conductive layer is coated with a foil dielectric board.

A multi-layer lamination process is used to bond all conductive layers together through a medium. The nuclear material is the double-sided foil in the factory. Because each core has two sides, this is true even if the number of conductive layers of the PCB board is fully utilized. Why not use foil on one side and core structure on the rest?

The main reason is: the cost of the PCB board and the degree of bending of the PCB board.

Cost advantage of uniform PCB board Due to the lack of dielectric and foil layers, the cost of raw materials for odd-numbered PCB boards is slightly lower than that of uniform PCB boards. However, the processing cost of odd-numbered PCB boards is significantly higher than that of even-numbered PCB boards.

The processing cost of the inner layer of the PCB is the same, but the foil/core structure obviously increases the processing cost of the outer layer. The odd-numbered PCB board needs to add a non-standard cascaded core bonding process on the basis of the core structure process. Compared with the nuclear structure, the production efficiency of plants with foil added outside the nuclear structure will be reduced.

Before lamination and bonding, the outer core requires additional processing, which increases the risk of scratches and etching errors on the outer layer.

Balancing the structure to avoid bending The best reason to design a PCB board without odd layers is that the odd layer PCB boards are easy to bend. When the PCB board is cooled after the multilayer circuit bonding process, different lamination tensions will cause the PCB board to bend when the core structure and the foil structure are cooled. As the thickness of the circuit board increases, the risk of bending the composite PCB board with two different structures is greater. The key to eliminating PCB board bending is to use balanced cascading. Although the PCB board has a certain degree of curvature that can meet the specification requirements, the subsequent processing efficiency will be reduced, resulting in an increase in cost.

As assembly requires special equipment and processes, the accuracy of component placement is reduced, thereby reducing quality. Solve the printed circuit board (PCB) layout related to DC/DC converters

Use a uniform PCB board When there are strange PCB layers in the design, the following methods can be used to achieve balanced cascading, reduce PCB board production costs, and avoid PCB board bending.

The following methods are ranked in the preferred level. 1. A signal layer and use. This method can be used if the power layer of the PCB is designed to be uniform and the signal layer is odd.

The added layer will not increase the cost, but it can shorten the delivery time and improve the quality of the PCB board. 2. Add an additional power layer. This method can be used if the power layer of the PCB is designed to be odd and the signal layer is even. An easy way is to add a layer in the middle of the cascade without changing other settings. First, follow the odd-numbered PCB board layout, and then mark the remaining layers in the middle of the copy formation.

This is the same as the electrical properties of foils applied to thickened formations. 3. Add a blank signal layer near the center of the PCB cascade. This method can minimize the cascading imbalance and improve the quality of the PCB board. First route through the odd-numbered layers, then add a blank signal layer, and mark the remaining layers.

It is used in microwave circuits and mixed-medium circuits (mediums have different dielectric constants). Advantages of balanced cascaded PCB: low cost, not easy to bend, shorten delivery time, and ensure quality.