On-Site Operation Guidelines | Standard PCB Measurement Process & Precautions

The stability and accuracy of PCB optical dimensional measurement results depend on standardized on-site operation specifications, rather than equipment hardware performance alone. Most data deviation and misjudgment problems in factory inspection are caused by irregular operation, improper workpiece placement, environmental interference and insufficient daily maintenance. This article sorts out the complete standard operation process and key precautions for SIG video measuring machines in on-site PCB measurement, providing practical guidance for front-line operators.

Complete PCB detection operations are divided into six standard links: pre-inspection preparation, workpiece placement, program calling/programming, automatic measurement, data verification and report export, and post-inspection finishing.

Pre-inspection preparation includes environmental adjustment, workpiece pretreatment and equipment inspection. The equipment shall be placed away from vibration sources such as drilling machines and punching machines, and preheated for a short time to stabilize the optical system. Direct sunlight on the workbench shall be avoided to prevent external light interference. Operators need to wear dust-free gloves to take PCBs, remove surface dust and milling debris to avoid false edge recognition. Clean the glass workbench and lens with professional cleaning tools to ensure unobstructed optical paths.

For workpiece placement, rigid FR4 PCBs can be directly laid flat on the workbench. Ultra-thin boards and FPC flexible boards need professional fixtures for flattening to eliminate warpage and ensure the workpiece is on the same focal plane. Workpieces can be placed randomly without manual axis alignment, but shall not exceed the effective stroke range of the workbench to avoid collision during equipment operation.

For program operation, mature mass production programs can be directly called, and operators need to confirm that program tolerance parameters and optical settings match the current PCB version. For new prototype workpieces, complete manual programming and first-article calibration are required, and key dimensional data shall be manually verified to ensure program accuracy before formal batch detection.

During automatic optical dimensional measurement, do not touch the workbench or block the optical path. Observe the imaging state in real time. Pause the program in time to adjust light source parameters and workpiece placement if abnormal reflection or fuzzy contours occur. After the measurement is completed, systematically verify NG out-of-tolerance items, exclude external interference factors such as workpiece warpage and surface dirt, and confirm defective workpiece dimensions before judgment.

After the inspection, classify and store workpieces, clean the workbench debris, and turn off the equipment power to complete standardized 5S management. In actual on-site operation, operators need to focus on key details: light source brightness shall be adjusted according to workpiece characteristics to avoid dimensional deviation caused by excessive or insufficient light; mass production programs shall not be modified without administrator authority; regular equipment calibration and maintenance shall be carried out to maintain long-term measurement accuracy.

Standardized operation is the premise of stable PCB measurement. Following complete operation specifications can effectively reduce human-induced errors, give full play to the advantages of video measuring machine optical dimensional measurement, and provide reliable quality basis for PCB factory inspection.