Conformal Coating Thickness Measurement for Automotive PCB Boards

I. Pain Points in Conformal Coating Thickness Measurement on PCB Boards

• Insufficient coverage in complex areas: High-density component regions, chip edges, and connector pins are difficult to inspect effectively. This often leads to a high risk of missed defects in critical safety components.

• Challenges in precision and consistency control: Standard inspection often suffers from limited accuracy and significant variation between production batches. Manufacturers frequently lack the clear data support needed to define strict pass/fail criteria.

• Limitations of traditional inspection methods: Destructive testing is inefficient and costly. Traditional non-destructive methods, such as laser triangulation, struggle with transparent coatings, reflective materials, and complex surface geometries.

• Poor adaptability for inline inspection: Legacy solutions are difficult to integrate into high-speed production lines. This results in slow inspection speeds that create significant production bottlenecks.

II. SinceVision Solution: Thickness Measurement for Automotive PCB Boards

To address these challenges, SinceVision provides an efficient, non-contact inline solution based on spectral confocal sensing technology. This implementation ensures a clear and controllable engineering path.

• Precise positioning of critical areas: After coating and curing, the PCB is guided by a vision positioning system. The sensor is directed to 5 to 9 predefined measurement points. These points are selected based on failure analysis, focusing on high-risk areas like chip edges and connector pins.

• High-speed inline measurement: The SinceVision SCI00532 completes a single-point measurement in 0.5 seconds or less. The total inspection cycle per board is maintained within 5 to 8 seconds, matching the production line takt time.

• High-precision thickness evaluation: Real-time evaluation is performed against predefined standards (e.g., 30μm to 200μm). When measuring transparent coatings, the sensor beam forms two focal peaks at the coating surface and the substrate interface. By inputting the refractive index, the system calculates the wavelength difference to determine exact coating thickness.

III. Project Advantages

• Micron-level ultra-high precision: As a specialized confocal displacement sensor for thickness measurement, the SCI00532 offers a resolution of 0.006μm and linear accuracy of ±0.2μm. This ensures highly accurate data and batch consistency for coatings ranging from 30μm to 200μm.

• Strong material compatibility: Using proprietary photosensitive algorithms, the sensor effectively handles highly transparent coatings and highly reflective substrates. It maintains performance on metal pins, low-reflectivity surfaces, and rough textures.

• Efficient inline integration capability: The sensor features an ultra-high sampling rate of 33kHz. Combined with a measurement speed of 0.5s per point, it enables full-board inspection within 5 to 8 seconds to seamlessly match high-speed assembly lines.

• 25mm safe working distance: The SCI00532 provides a 25mm working distance. This maintains a safe clearance between the sensor probe and high-density PCB components, preventing physical collisions during high-speed automated inspection.

IV. Recommended SinceVision Sensor Solution

The implementation of SinceVision point spectral confocal displacement sensors provides automotive enterprises with a factual, data-driven inspection solution. It overcomes the limitations of traditional methods regarding material adaptability and production efficiency. This technology improves product quality, optimizes manufacturing processes, and strengthens market competitiveness.