Acceptability of Printed Circuit Board Assemblies

When determining the acceptance criteria to use in building or manufacturing a printed circuit board assembly (PCBA), one first and foremost must look at the contract between the supplier and the purchaser of the product. Always determine the needs and/or wants of the customer through contractual commimications or, less formally, by talking to the customer if a contract is not detailed enough or does not even exist. 

Many standards cover printed circuit board assemblies. Most major electronics manufacturers have their own internally developed workmanship standards. Several industry and military standards also exist. However, the joint industry standard IPC-A-610D, Acceptability of Electronic Assemblies, is the standard most often referenced for criteria defining reliable solder connections. This standard was developed by the Institute for Interconnecting and Packaging Electronic Circuits (IPC) (www.ipc.org). 

T. Radhakrishnan and S.M. Hegde, An Analysis of the Errors Involved in Component Pick Up and Registration for Automated Printed Circuit Board Assembly, paper no. D-453, accepted for publication in the ASME/Journal of Engineering for Industry. 

Defects are defined as those artifacts that are outside the window of acceptable attributes for the finished circuit board assembly. Thus, defects are not limited to the solder joints, specifically, but can also include damage to the circuit board material as well as degradation to component structures (e.g.,molding compound, leads or terminations, etc.). Defect types and their allowable frequencies (often expressed in parts-per-million solder joints or product units) vary with the different assembly processes and applications. Therefore, product drawings, in conjunction with industry standards (e.g., IPC-610), are used to establish accountable defect types for printed circuit boards. 

---