Rules adhered by PCB design companies to minimize the cost of fabrication! Designing of printed circuit board is not as easy as it may seem to be! Therefore, number of rules & regulations are followed for designing the boards by the PCB design companies in order to get the respective layouts-as quality can make a drastic difference. Following are some printed board design rules:
*Single sided PCB: Circuit boards can be designed in two forms single sided and double sided. But as far as possible, companies prefer single sided because circuitry can be routed easily with the use of jumpers on these boards, as compared to the double sided boards. Moreover, double sheets also causes price hike of 1 to 2 times more than single sided boards. Hence, so far companies prefer these as the cheapest PCB for making out consumer products.
*Panelisation of PCB: Panelisation plays major role in cutting the cost of PCB fabrication. This is because of the prominent fact that it helps to save up 80% to 90% of PCB lamination. However, if not done so, wastage up to50 % would occur which is not at all worthwhile. Therefore, usually manufacturers prefer standard sizes that comprise of dimension 40 inches * 48 inches.
*Small size: The fundamental rule of printed circuit board design is to use small size of board during its layout, in order to have best output of fabrication. Few points taken into considerations in relation to size are spacing, track width and various other constraints.
*Silkscreen: It should be either eliminated or minimized up to a great extend because if used, later it would cause difficulty in trouble shooting. Hence, PCB companies itself or while recommending make sure that if they are using silkscreen on top overlay then they won't be using it again on bottom overlay.
*Reduce number of holes: The basic role when it comes to drilling is keeping it simple as much as possible. Therefore, utilization of machine is not preferred much as it would be raising the price of board.
*Reduce type holes: Common drill bit sizes are preferred by the companies while designing of boards which comprise of 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.2mm, 1.5mm, 2.0mm and 3.0mm. Changing these drill bits are avoided because making changes by machine takes a lot of time that eventually causes an effect on the cost of PCB.
*Limited track width and track spacing: Likewise, printed company adhere the rule for the reduction in holes and types holes, similarly they also make it a note to have minimize track width and spacing. For example, http://supportforums.blackberry.com/t5/user/viewprofilepage/user-id/1258872 for designing of 0.3mm width, they make use of 0.5mm and similarly, for spacing they use 0.5mm, when 0.3mm is required. Eventually, http://www.purevolume.com/listeners/pcbonline this would help yield a productive printed circuit board during the fabrication period with an effective cost.