The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving

The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

Abstract

In the electronics manufacturing industry, as products move towards high density and miniaturization, the quality of solder paste printing in SMT (Surface Mount Technology) directly determines the reliability of the final product. 3D SPI (Three-dimensional Solder Paste Inspection) technology, with its high-precision detection capability, has become an indispensable quality control method in the SMT process. This article will delve deeply into the technical principles, core functions, intelligent applications of 3D SPI, as well as its interaction with the preceding and subsequent processes, helping you gain a comprehensive understanding of how to enhance production efficiency and reduce rework costs through 3D SPI. It also looks forward to the future development trend of the integration of AI and Industry 4.0.

1.3D SPI Technology: Quality Guardian in SMT Manufacturing
In the SMT production process, 74% of defects originate from solder paste printing issues. Traditional 2D SPI can only detect planar defects, while 3D SPI, through three-dimensional imaging technology, can accurately measure key parameters such as the volume, height, and shape of solder paste, significantly improving the defect detection rate.

1.1 Laser triangulation method
Early 3D SPI adopted the laser triangulation method. By projecting a laser onto the solder paste surface and using a CCD camera to capture the reflected light spot, the height was calculated in combination with the triangular geometric relationship. This method can only measure the height of a single point and has relatively low efficiency.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
Based on the imaging point A and the reference point O illuminated on the object, calculate the 2D image distance L from each point on the object to this reference point. According to the principle of trigonometry, convert the height H of the object using the 2D image distance L.

1.2 Multi-line laser scanning technology
To enhance the detection speed, the industry has introduced multi-line laser scanning technology, which can simultaneously measure the height of multiple points. However, it still has the following limitations:
Only the laser irradiation point can be precisely measured, while the rest of the area needs to be fitted and estimated, which affects the accuracy.
Due to the reflection on the surface of the object, the PCB needs to be sandblasted (which is not feasible in actual production).
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

1.3 ALeader Structured Light 3D Technology (PMP) of Shenzhou Vision
At present, the mainstream 3D SPI adopts Phase Measurement Profilometry (PMP), namely structured light 3D technology. The principle is as follows:
The projection grating (sinusoidal grating) illuminates the surface of the PCB, forming alternating optical stripes of light and dark.
The camera captures the deformed stripes and calculates the height information through phase changes.
The double-projection grating technology is adopted to eliminate the error in the shadow area and improve the measurement accuracy.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
(Single projection with shadow vs dual projection can complement each other)

Compared with laser scanning, PMP technology has the following advantages:
✔ Full field coverage, no blind spot detection
✔ Resistant to PCB color and reflection interference
✔ Suitable for high-density, micro pads (such as 01005 components)

2. Core Functions and Applications of ALeader 3D SPI
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

2.1 High-precision detection capability
Volume, area and height measurement: volume, area, height, offset, insufficient tin, excessive tin, continuous tin, tin tip, gold finger, contamination, red glue process and other appearance defects

Anti-interference ability: Automatically compensates for PCB warpage and ADAPTS to PCBS of different colors (green, red, black, etc.).

The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
The 3D SPI should have the function of automatically compensating for board bending without any additional operation

The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
3D SPI should ensure the same performance level on PCBS of any color

Multiple MARK point recognition: Supports non-standard MARK point positioning such as circular, cross-shaped, and rectangular ones.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

2.2 Intelligent Data Analysis and Process Optimization
Height distribution map: Visualize the height distribution of solder paste and quickly locate defective areas (such as uneven scraper pressure, steel mesh problems, etc.).
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

Cpk Trend monitoring: Real-time statistical process control (SPC), analyzing printing stability.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

Early warning function: Automatically alarm when critical defects occur continuously, and adjust the process parameters in advance. When control points continuously appear on the same side of the set value range, it can be considered that defects in solder paste printing are about to occur. At this point, 3D SPI should start to prompt and warn.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
2.3 Automated programming and quick line changing
Gerber/CAD import: Automatic programming is completed within 5 minutes, reducing the reliance on operators.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
Step steel mesh inspection: Supports independent parameter Settings for special pads (such as BGA).

3. Data Linkage between ALeasder 3D SPI and intelligent manufacturing

3.1 Closed-loop feedback with the printing press
When missed printing or excessive tin is detected, it automatically feeds back to the printing machine to adjust the pressure of the scraper or clean the steel mesh.
Identify the Bad Mark board, notify the surface mount technology (SMT) machine to skip the defective board positions, and improve production efficiency.

3.2 Collaborative Detection with AOI
The critical data of 3D SPI can be transmitted to the AOI before or after the furnace to achieve key re-inspection.
The three-point alignment function (3D SPI + pre-furnace AOI + post-furnace AOI) helps trace the root cause of defects.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield
The built-in SPC system can integrate the data and images detected in the three stages, facilitating communication with engineers to determine which stage has gone wrong and what caused the problem.

3.3 Comply with IPC-CFX standards
Based on the IPC-CFX communication protocol, data intercommunication among devices is achieved, facilitating the construction of smart factories.
The Key Role and Intelligent Application of 3D SPI Technology in SMT Manufacturing: The Ultimate Solution for Improving SMT Yield

4. Future development trends
Ai-driven intelligent detection: Combining deep learning to optimize defect classification and reduce false alarm rates.
Real-time adaptive adjustment: Forms a dynamic closed-loop control with the printing machine and reflow soldering.
5G+ Industrial Internet: Enabling remote monitoring and big data analysis, and enhancing predictive maintenance capabilities.

Conclusion

3D SPI technology has become a core link in SMT intelligent manufacturing. ALeader from Shenzhou Vision has significantly improved production yield and efficiency with its high-precision detection algorithms, intelligent data analysis, and equipment interconnection capabilities. In the future, with the deep integration of AI and Industry 4.0, 3D SPI will further drive electronic manufacturing towards the "zero defect" goal and help enterprises achieve intelligent upgrades.