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Thermal imaging technology in printed circuit board inspection

The design and production of printed circuit boards (PCB) is an extremely delicate process, and it is fairly difficult to discover design imperfections or manufacturing defects in circuit boards. There might be such a time when you powered a freshly built PCB, only to find you’ve hit the current limit. Safely, you explore the board with your finger, but no parts are hot to the touch, and also, probing around with a multi-meter doesn’t pick up any unexpectedly low resistances, short circuits, or significant voltage drops. Besides, traditional optical methods are inadequate to track down major faults.


Alternative inspection methods such as thermal imaging are highly required to spot PCB faults. Thermal imagers can detect minute temperature differences across their view, allowing us to identify quickly any components that are consuming current because any parts of the board that draws current will generate heat and can be easily arrested by a thermal imager.


A PCB starts to heat up when being supplied with voltage because electric current flows through the board. PCB thermal fields can be determined and visualized by a thermal imager. With adequate knowledge of the thermal field, manufacturing defects could be detected early in the design process. Thermal imaging can be used to visualize the excessive heating of certain components caused by incorrect mounting, short circuits, or insufficient tin during soldering including the following uses:


1. Optimizing the chip routing

Designers could figure out the overall allocation of heat and add coolers and other components accordingly with the help of thermal imagers. When compiling the code for an FPGA, chip routing may be less than optimal. Temperature evolution in different regions of interest (ROI) can be displayed through FOTRIC AnalyzIR to discover excessive loads on some areas of a greater chip.



Historical time-temperature curves of a part with excessive load (Output from AnalyzIR)










3D temperature distribution can better visualize the heat anomaly (Output from AnalyzIR)






2. Shortening PCB development time

Thermal imaging shortens the PCB development time and enhances its design process. If the layout design is defective, a high current would flow through some areas of the PCB and generate excessive heat, which in turn makes the PCB unstable and shorten its service life. However, it is not easy to discover these design defects without a thermal imager. 


By capturing the heat anomaly of components in the circuit board, the FOTRIC 600 R&D can quickly spot the design defect and record the heat generation process.


PCB boards 6s

9s 17s


3. Issue detection after PCBs are mounted

Thermal imagers can inspect substantial numbers of mounted PCBs simultaneously and facilitate immediately identifying a wide range of issues after PCBs are mounted.




FOTRIC 600 R&D can inspect large numbers of mounted PCBs simultaneously







4. Heating up due to cold joint

A component that is incorrectly mounted with cold joints may experience significant heating. In the first phase of traditional equipment testing, such imperfections often slip by undetected, and in long-term operation, components may stop functioning due to high temperatures, and then the entire board may stop working. These issues can be detected by a FOTRIC 600 R&D camera immediately after PCB is mounted and activated without any need for functional testing. Operators could find any deviation from the norm by comparing the infrared images of a tested PCB with the functional PCB without any need for design knowledge.

Good product Defective product


RECOMMENDED THERMAL CAMERAS


FOTRIC 600 R&D station can better test the chip and discover the PCB design defects based on its advantages:

  • 20μm & 50μm macro lens and great sensitivity of 30 mK.

  • Full radiometric video streams with an adjustable frame rate of up to 30Hz.

  • Brilliant measurement accuracy: ± 2 °C or ± 2 %, whichever is greater

  • Powerful analysis software on PC: AnalyzIR


MORE QUESTIONS?


To learn more about FOTRIC infrared thermal imaging cameras, please visit www.fotric.com or contact info@fotric.com for any inquiries.

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