The designer may design an odd layer printed circuit board (PCB). If no additional wiring layer , why use it? Do not allow the board to reduce the layer thinner it? If the board is at least one layer , do not lower the cost of it ? However, in some cases , an additional layer but will reduce costs.
The circuit board has two different structures : a core and cladding structure of the foil structure.
In the core structure , the circuit board in all the conductive layer is applied on the core material ; in the foil cladding structure , only the circuit board internal layer was deposited on the conductive core material , an outer conductive layer deposited foil dielectric plate . All the conductive layer through the dielectric multilayer lamination process using an adhesive together.
Nuclear plant material is deposited on both sides of the foil sheet . Since each core has two faces , full use of the time , PCB conductive layers even. Why not side with the remaining dressing with foil and nuclear structure? The main reason is : the curvature of the cost of PCB and PCB 's .
Even layers of the circuit board cost advantage
Because the media and apply a layer of foil, less the cost of raw materials is slightly lower than the odd PCB board even layer PCB. However, the odd -layer PCB processing costs are significantly higher than the even layer PCB. The same inner processing costs ; but the foil cladding / core structure significantly increases the cost of the outer handle .
Odd- layer PCB need to increase nuclear layer lamination bonding process on the basis of non-standard process on the nuclear structure . Compared with nuclear structure , nuclear structure in the outer wrap foil plant added productivity will decline. Before the laminating adhesive , the need for additional external nuclear process, which increases the risk of scratches and the outer layer is etched errors .
Avoid bending equilibrium structure
Odd- layer PCB design without the best reason is : the odd -layer circuit board easily bent . When the PCB multilayer circuit bonding process after cooling , nuclear structure and different cooling structure when deposited foil laminated PCB bending causes tension . With increasing thickness of the board , with the risk of the composite structures of two different PCB , the greater the bending . The key is to eliminate the use of a curved board balanced stacked . Although a certain degree of bending PCB to specifications , but subsequent processing efficiency will decrease , resulting in increased cost. Because the need for special equipment and technology assembly , component placement accuracy decreases, it will damage the quality.
Use an even layer PCB
When the odd- layer PCB design appears, the following methods can be used to balance stacked reduce PCB production costs and avoid PCB bending . The following methods are arranged according to the preferred level .
1 . Layer signal layer and use . If the power supply layer of the PCB design and even an odd number of signal layers can be used this way . Additional layer does not increase the cost , but it can shorten lead times and improve quality PCB .
2 . Increase an additional power supply layer . If the design of PCB layers is odd and the signal power level is even such a method may be employed . A simple method is provided without changing other conditions in the formation of the laminate plus one intermediate . Press the odd -layer PCB routing species , then copy formations in the middle, marking the remaining layers. This thickening formation and electrical characteristics as the foil wrap .
3 . PCB stacked near the center to add a blank signal layers. This method minimizes imbalance laminated , to improve the quality of the PCB. Press the odd -layer wiring , and then add a layer of blank signal layers , marking the remaining layers. Microwave circuits and mixed media ( media with different dielectric constants ) circuit types using .
Balance layered PCB advantages: low cost , easy to bend, shorten delivery times , quality assurance .
