PCBA manufacturing defect-defect universe-PCB

- Feb 27, 2017-

PCBA manufacturing defect-defect



PCOLA-SOQ  is a method to gauge the effectiveness of testing a printed circuit board assembly (PCBA) in manufacturing to ensure the PCBA is devoid of manufacturing defects.

PCBA manufacturing defect

The objective of PCBA manufacturing is to attach correct, working, and properly oriented components to their intended locations with connections that are formed to establish reliable mechanical and electrical connectivity. PCBA defects will evolve with technology as new component package types are adopted and assembly processes improve over time.

A PCBA manufacturing defect has been defined as “An unacceptable deviation from a norm”. The term “unacceptable” is key; action is required to repair the defect, and/or to assure the process that allowed it to happen is improved. Defects should not be passed on.

Thus a PCBA manufacturing defect is ‘an unacceptable mounting of a part and/or an unacceptable formation of a connection (solder joint, press-fit connection, etc.).

PCBA manufacturing defect universe

The PCBA manufacturing defect universe comprises all manufacturing defects potentially created in the process of assembling and attaching components to a printed circuit board (PCB). This includes defects

  1. Related to components on the PCB.

  2. Related to the attachments points (typically “pins”) of the components.

For every PCBA, a bill of materials (BOM), x-y locations and component orientation information are used to assemble the PCB. The defect universe is the enumeration of all the potential defects using the PCB assembly information.

The PCBA defect universe is an enumeration of ALL potential defects in the PCB assembly process and is not reduced by the defect detection capability of a manufacturing test process. The fact that a given test technology may not be capable of detecting all defects does not mean untestable defects should be ignored.

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