PCB manufacturing testing encompasses a series of inspections and validations conducted during and after the fabrication process to ensure quality, reliability, and compliance with design specifications. These tests range from visual checks to advanced electrical measurements, addressing potential defects like shorts, opens, misalignments, or material inconsistencies. Unlike final product testing, manufacturing testing focuses on intermediate stages, enabling early detection of issues that could escalate into costly rework or field failures.

A critical manufacturing test is the automated optical inspection (AOI), which uses high-resolution cameras and image processing software to detect surface defects, such as solder bridging, missing pads, or incorrect component placement. AOI systems are typically deployed after solder paste application and component placement but before reflow soldering. Another essential test is the in-circuit test (ICT), which verifies electrical connectivity by probing specific points on the PCB to check for opens, shorts, and component values. ICT machines use bed-of-nails fixtures or flying probes to contact test points, providing detailed fault diagnostics.

Environmental and reliability tests are also integral to PCB manufacturing. Thermal cycling, humidity testing, and vibration testing simulate real-world operating conditions to assess long-term durability. For high-reliability applications, such as aerospace or automotive electronics, PCBs may undergo accelerated life testing (ALT) or highly accelerated stress screening (HASS). Data from these tests feed into statistical process control (SPC) systems to monitor production trends and optimize processes. Future trends include the integration of AI for real-time defect classification and the adoption of 3D AOI for complex multilayer PCBs.