Zhixiang Shijue completed the PCB board soldering inspection test

In the electronics manufacturing industry, the quality of PCB soldering directly affects circuit performance, product reliability, and the lifespan of the entire device. Issues such as solder misalignment, cold solder joints, insufficient solder, or excessive solder can often lead to functional abnormalities during subsequent assembly and use, and even product failure. Therefore, achieving high-precision and stable detection of solder position and condition during the production process has become a key focus for manufacturers.

Recently, Zhixiang Shijue's technical team completed a soldering inspection test on PCB samples provided by a customer. The test focused on verifying the accuracy of solder joint positions, the clarity of their outlines, and the stability of the overall imaging, providing a reliable basis for the customer's subsequent automated inspection solutions.

Soldering process testing requirements

In the PCB electronics manufacturing industry, laser soldering technology is widely used for soldering micro-components and connecting complex circuit structures due to its concentrated energy, high soldering precision, and small heat-affected zone. Whether for basic components such as resistors, capacitors, and inductors, or high-density integrated circuits, laser soldering exhibits excellent process stability.

However, the improvement in soldering technology has also placed higher demands on post-soldering inspection. The uniformity of solder joints, the appropriate amount of solder, and the accuracy of their placement directly determine whether the soldering process meets standards. Post-soldering inspection is not only a crucial guarantee for the laser soldering process but also an important reflection of a company's responsibility for product quality.

Visual inspection to determine solder quality

In current PCB solder joint inspection, machine vision inspection is the most direct and widely used method. The system acquires images of solder joints using a high-resolution camera, analyzes the shape, size, and location of the solder, and compares them with predefined standards to determine whether the soldering quality is up to standard.

Compared to manual inspection, machine vision offers the following advantages:

Fast inspection speed, adaptable to high-speed production lines

High result consistency, avoiding human error

Reliable identification of minute soldering defects

Supports data recording and quality traceability

In some high-reliability applications, PCB solder joint inspection may be combined with electrical performance testing, X-ray inspection, and thermal imaging inspection; however, visual inspection remains the most core and frequently used inspection method on the production line.

Detection difficulties

PCB solder joint inspection faces multiple challenges in practical applications:

Small solder joint size requires high imaging resolution and lens resolving power.

Strong reflectivity of metallic solder easily leads to overexposure and high-light interference.

Densely distributed solder joints result in extremely low tolerance for positional deviations.

Fast production line cycles necessitate long-term stable system operation.

Under these conditions, conventional imaging solutions often struggle to simultaneously achieve clarity, stability, and measurement accuracy.

Professional Solution: Telecentric Lens + Industrial Camera + Light Source

To address the client's inspection needs, the Zhixiang Vision technology team developed a complete machine vision testing solution:

Telecentric Lens:

Effectively eliminates perspective errors, ensuring the accuracy of solder joint size and position measurements, particularly suitable for high-precision positioning and comparison applications.

Industrial Camera:

Provides stable, high-resolution image output, offering a reliable data foundation for solder joint recognition and algorithm analysis.

Customized Light Source Solution:

By optimizing the illumination angle and brightness distribution, it effectively suppresses strong reflections on the solder surface, enhancing the contrast between the solder joint and the substrate.

During testing, technicians conducted multiple rounds of adjustments to the camera mounting height, lens focal length, and light source position, ultimately achieving stable and clear imaging results.

Test results: Image formation is stable and reliable.

From the actual imaging results, the solder joints on the PCB board have clear outlines and well-defined boundaries, with a clear distinction between the solder joint area and the background. Even in areas with dense solder joints, the system can still stably display the solder position, providing a solid image foundation for subsequent algorithm judgment and automated detection.

Test results show that this solution has good adaptability and reliability in solder position detection, and can meet the application needs of customers in actual production lines.

PCB visual inspection applications

PCB inspection is a crucial sub-field of machine vision applications, encompassing multiple stages including solder inspection, character recognition, defect detection, and dimensional measurement. Leveraging its extensive experience in industrial cameras, lenses, light sources, and vision system integration, Zhixiang Shijue has provided professional vision testing and solution support to numerous electronics manufacturing companies.

In the future, Zhixiang Shijue will continue to focus on the PCB and electronics manufacturing industries, constantly optimizing imaging solutions and inspection efficiency to help customers achieve higher quality and more stable intelligent manufacturing upgrades.