Manufacturability in printed circuit board (PCB), refers to Design for Manufacturability (DFM), Design for Assembly (DFA), which defines the ability of a PCB design to meet PCB manufacturing capabilities and PCB assembly capabilities.
With component packages getting smaller, PCB designs getting denser, and assembly process margins getting tighter, PCB designers are facing increasingly tougher challenges. Designers need to resort to specific checks at each step of the design to ensure the final product will function as intended.
DFM vs. DFA
The designer is not the only one who involved in the PCB industry. PCB fabricators and assemblers also pay their crucial roles. Fabricators manufacture the bare boards, while assemblers mount components on them. If everything goes well, the board starts functioning. However, depending on chance is a risky and expensive way for contract manufacturer to make products that depend on PCBs to function properly. To reduce the risk and lower the expenses, MADPCB recommends designers to resort to DFM and DFA analysis before forwarding the manufacturing files, like Gerber to turnkey PCB assembly manufacturer for further manufacturability checks.
DFM Checks
Several factors are important to the PCB fabricator in charge of building a circuit board. The designer mainly conveys the information in the form of electronic documentation as Gerber files, or ODB++. The information provides details on the PCB materials and properties, the stack-up, copper thickness information of each layer, drill details, aperture details, net list, surface finish, plating finish, soldermask and silkscreen information, assembly information, test point details, and details on the panel design.
The designer generates the above information to ensure that the board is manufacturable. The fabricator runs a DFM checks on the information available to ensure that with their existing capabilities they can manufacture the circuit board.
DFA Checks
The scope of DFA checks differs from that DFM, although many of the strategies are interchangeably applicable in a general sense to all areas of PCB design. Related to the components that will go on to the PCB for mounting, DFA checks mainly considers reduction and combination of components, their standardization, minimization of risk, simplification, clarity, and an understanding of the capabilities of the PCB assembler.
Although each of the above points are very important for PCB assembly, the final strategy is the most explicit, as it decides the ability of the designer to achieve the remaining. For instance, if the designer has specified the use of 0201 SMD packages, the assembler must have pick-and-place machinery capable of handling such small packages.
DFA checks can help in improving the reliability of the PCB assembly. The analyst checks the source of the components that should have come from reliable manufacturers with assurances of accuracy, stability, and reliable delivery. For instance, if a manufacturer has marked the status of a components as obsolete or end-of-life, the designer should rather use a suitable replacement instead.