I. The primary reason for conducting PCB strain measurement is to ensure the reliability of electronic products and prevent potential mechanical stress damage. Printed circuit boards (PCBs) are subjected to various mechanical stresses during manufacturing, assembly, and transportation. These stresses may lead to issues such as solder joint cracking, circuit damage, and substrate cracking, thereby affecting the reliability and lifespan of the product.

II. Specific Reasons and Impacts of PCB Strain Measurement

1. Mechanical Stress During Manufacturing: Excessive mechanical stress during stages such as SMT, DIP assembly, and reliability testing can lead to problems like solder ball cracking, circuit damage, pad lifting, and substrate cracking. If these issues are not detected and addressed promptly, they may cause product failures during use.

2. Mechanical Stress During Assembly and Transportation: In processes such as panel separation and assembly, PCBs are prone to mechanical stress, which can result in solder joint cracking or PCB delamination. With the trend toward thinner and lighter electronic products, reduced component sizes and lower solder joint strength make them more sensitive to mechanical stress.

3. Application of New Materials and Processes: The adoption of lead-free soldering processes and new laminated materials alters the mechanical characteristics of PCBA. Strain testing is necessary to verify process compatibility.

III. Methods and Standards for PCB Strain Measurement

1. Testing Methods: Strain gauges are used to measure PCB strain. The strain gauges must be selected according to the PCB dimensions and ensure close contact with the board surface. During data acquisition, sampling frequency and filtering parameters need to be configured to monitor strain changes in real time.

2. Standard Specifications: Compliance with the IPC/JEDEC-9704 standard is required, specifying the selection of test points, data acquisition frequency (recommended ≥500 Hz), and strain threshold determination methods. Typically, ±500 με (microstrain) is used as a reference threshold, which may need adjustment for different components.