What is AOI and IPQC in PCB manufacturing process

The PCB manufacturing process is long, and each process requires strict inspection (IPQC: Input Process Quality Control). There are three stages that must be tested: AOI (Automated Optical Inspection) must be performed after etching the inner layer and etching the outer layer. The finished board must be tested for electrical performance.

AOI: Automatic optical inspection. It is a representative method commonly used in industrial processes, and is a device that detects common defects encountered in welding production based on optical principles. The surface state of the finished product is obtained optically, and foreign matter or pattern abnormality is detected by image processing. When it is automatically detected, the machine automatically scans the PCB through the camera, collects images, and compares the solder joints tested with the qualified parameters in the database. After image processing, the defects on the PCB are checked, and the defects are displayed/marked through the display or automatic signs. Come out for repair by maintenance staff.

IPQC: It is the abbreviation of “Input Process Quality Control”, which is responsible for monitoring the quality of semi-finished boards. Since the inspection method adopted by IPQC is to patrol inspection between each process in the production, it is also called patrol inspection. The general method adopted by IPQC is sampling inspection. The inspection contents are generally classified into sampling inspection of product quality of each process, inspection of operation methods and methods of operators of each process, and inspection of contents in the control plan.