SPI (Solder Paste Inspection) refers to the solder paste inspection system. The main function is to detect the quality of solder paste printing, including volume, area, height, XY offset, shape, bridging and so on. How to quickly and accurately detect very small solder paste, generally using PMP (phase modulation profile measurement technology) and Laser (laser triangulation) detection principle.
1. Reduce the defective rate of finished products. With the increasing precision of electronic products and the trend of lead-free soldering, patch components are becoming more and more miniature, so the quality of solder paste printing is becoming more and more important. SPI can effectively ensure good solder paste printing quality and greatly reduce the possible defect rate of finished products. Some PCB components such as BGA, CSP, PLCC chips, etc., due to the light shielding caused by their own characteristics, AOI can not detect the patch after reflow. The SPI is controlled by the process to minimize the disadvantages of these devices after the furnace.
2. Reduce costs. The introduction of SPI can effectively reduce the unqualified rate of the original finished PCB by more than 85%; the cost of rework and scrapping is greatly reduced by more than 90%, and the quality of the manufactured products is significantly improved. As a means of quality process control, quality hazards can be found in time before reflow soldering, so there is almost no possibility of repair cost and scrapping, which effectively saves costs. The combination of SPI and AOI, through real-time feedback and optimization of the smt production line, can make the production quality more stable, greatly shorten the unstable trial production stage that must be experienced when the new product is introduced, and the corresponding cost loss is more economical.
3. Improve production efficiency. It can greatly reduce the misjudgment rate of AOI on solder, thereby improving the straight-through rate and effectively saving the manpower and time cost of human error correction. According to statistics, 74% of the unqualified parts of the current finished PCB are directly related to solder, and 13% have an indirect relationship. SPI effectively compensates for the shortcomings of traditional detection methods through 3D detection methods.