Part 1: Introduction to PC-WP-011.
PC-WP-011*** is a permissible strain test standard for PCBs of different thicknesses.
Regarding the PC-WP-011 standard, the x-axis is the value of the strain rate and the y-axis is the value of the principal strain, and we have obtained the graph shown in the figure above according to the printed circuit board of different thicknesses, in which the trajectory of the test principal strain result is an unacceptable range value above the slope diagram, and the slope is the range value determined according to the thickness of the board.
2. The main components detected by PCB stress test are as follows:
1.BGA-like devices.
BGA of 27*27mm or more is required, including but not limited to FCBGA and CBGA. If there is no board greater than 27*27mm
The BGA with the largest BGA on the board or the BGA with stress concentration is preferred.
2.Stress-sensitive devices.
According to the identification of stress risk points distributed on the board, the following stress-sensitive devices are selected for evaluation:
A. Ceramic capacitors and ordinary capacitors (excluding soft terminal capacitors) in 10402 and above packages, and 1206 and above packages for ICT BST and other process tests.
b. SMD resistors, ceramic crystal oscillators, inductors, magnetic beads, PLO modules, gas discharge tubes, fuse kits, etc.
BGA stress testing is an important test technique in electronic packaging technology to evaluate the stress generated between BGA (ball grid array) pins and chips during the packaging process. Due to the high density and high reliability of BGA packages, specific methods and standards are required for BGA stress testing.
3. BGA stress test method.
At present, the most commonly used method of BGA stress testing in the industry is the resistance measurement method, which uses the change of the resistance value of the strain gauge to measure the stress of each link of the BGA in the generation process, and quantifies and analyzes the test data.
Fourth, BGA stress test environment.
The test process includes: board stress, plug-in stress, patch stress, solder stress, dispensing stress, assembly stress, ICT stress, FCT stress, drop stress, ** stress, stacking stress, etc.
When performing BGA stress testing, it is necessary to select appropriate test methods and standards according to the actual situation to ensure the accuracy and reliability of the test results. At the same time, the test results need to be analyzed and evaluated according to the actual situation to determine whether the performance and reliability of the BGA package meet the requirements.
Stress Testing Instrument Features:
1. This product has high resolution and can measure very small strains such as 1-2 micro strains.
2. The error is small, and the error accuracy can reach 03%。
3. Small size, light weight, portable design, convenient for operation and testing on the production line.
4. The measurement range is large, from elastic deformation to plastic deformation (1-2%), and the maximum can reach 20%.
It can measure both static and fast alternating stress.
5. It has all the advantages of electrical measurement, such as the measurement results are easy to transmit, record and process.
6. It can work in a variety of harsh environments, and can work reliably under the conditions of vibration, magnetic field, radioactivity, chemical corrosion, etc., as long as appropriate measures are taken.
7. Low cost, diverse varieties, easy to choose and use in large quantities.