SPI Inspection

SPI Inspection

SPI in SMT Process

In PCB assembly, SMT accounts for as much as 70% of the process, which means that almost all PCBA boards in electronic products rely on this process. Manufacturers typically use automated processes to complete the SMT process. PCB bare boards are fixed to the surface of the PCB Board after tin paste printing, component mounting, and reflow soldering, with SPI being used as a critical tool for detecting the quality of surface-mounted components prior to reflow soldering. It should be noted that SPI inspection of PCBs is considered mandatory in electronic manufacturing, as it helps to identify faults early, avoid production delays, and reduce manufacturing costs. During operation, inspection equipment uses high-resolution cameras and light sources to detect quality issues such as component position, direction, offset, and skew. If any solder paste deposits are detected, they are marked, and the operator corrects the errors to achieve efficient SMT assembly.

Composition of SPI Detection System

1.Solder Paste: Mixture of flux and solder that is used to join components on a PCB board.

2.Calibration Standards: Ensure the equipment is calibrated to project specifications and test accuracy is maintained.

3.Inspection Equipment: Comprised of a three-dimensional scanning system and an AOI unit for capturing images of electronic components on the surface of the PCB.

4.Light Sources: Provide illumination of electronic components to ensure proper capture by cameras.

5.Software: Utilized for image processing and analysis to detect faults, collect process data and generate reports.

6.Docking Stations: Transferring PCBs to the inspection area for processing.

7.Racks: Mounting equipment such as cameras, light sources, delivery systems, etc.

8.Controller: Controls the operation of the system, including the movement of the delivery system and the camera.

The Necessity of SPI Inspection in PCB Assembly

Advantage

1.Enhance PCBA Quality: Ensure accurate and consistent deposition of solder paste to improve project quality.

2.Time Efficiency: Early detection of defects during assembly saves time in the production process by reducing the need for rework.

3.Cost-effectiveness:  SPI inspection PCB is an added feature to our SMT services and is provided to customers free of charge. It is an essential quality control measure that helps identify errors before soldering, minimizing the need for costly desoldering and repairs that may damage components.

4.Improved Customer Satisfaction: High-quality circuit boards ensure customer satisfaction and enhance the reputation of your business.

Limitation

1.Limited flexibility: Typically used to verify the quality of solder paste printing and may not be effective for other aspects, such as the inspection of large components or high density interconnection PCB.

2.Lack of standards: Currently, there is no industry standard for SPI inspection, making it difficult to compare results between different software and machines.

3.Time-consuming calibration: Accurate results require machine calibration, which can be a difficult and time-consuming process.

4.Potential for false positives: There is a risk of false positives due to the presence of debris or dust on the board that may be mistaken for a defect.

5.Solder paste: The inspection of solder paste can be challenging due to its small size and variability, as well as the inability to inspect components beneath the solder paste layer.