Cell phones, computer monitors, televisions, and even some light switches contain printed circuit boards. Products like these sometimes go through multiple manufacturing companies before they are ultimately constructed. PCB fabricators have quite the job to do themselves, and they can often make mistakes that affect the long-term production of these products. Here are some common mistakes made by printed circuit board manufacturers:
Controlled Impedance Calculations: A controlled impedance used to slow down an electrical circuit in order to allow certain connections to perform before others within the circuit. One example of a controlled impedance is the coaxial cable that connects the antenna to a television. They are made up of inner conductors and an outer conductor, or shield. The dimensions of the conductors must be controlled in accordance with the strength and shape of the electrical field. This determines the impedance of the circuit. FPGAs, processors, RAMS, and flashes all require impedance controlled tracks to maintain a strict order in functionality. Meetings between designers and manufacturers are necessary to discuss these specifications.
Drill Constraints: Similarly to clearance, PCB fabricators also have drill constraints that limit the size of the drill. Exceeding the limit set by the manufacturer can increase cost of production drastically. A typical drill size lies between six and 14 millimeters, obviously dependant on the PCB’s size. The drill holes depend on the size of the connecting pin used. PCB fabricators and engineers must be in close communication during every single manufacturing project in order to ensure a consistently high-quality, flawless end product.
Clearance Issues: Lack of communication with an engineer can cause design issues that affect the assembly of each circuit board. Manufacturers have “clearance constraints,” that they must maintain between each layer of the circuit board. Often, an engineer will design a board below the minimum clearance constraint, and the manufacturer is incapable of producing a PCB with such a small constraint. Outlining manufacturing capabilities and having an in-depth meeting with the designing engineer on the project will eliminate this type of problem.
Ultimately these mistakes come as a result of miscommunication. PCB fabrication is a complicated process that requires many moving parts and specifications, so keeping the lines of communication between product manufacturer, PCB fabricator, and designer is crucial.