ST-P Series Laser Displacement Sensor in Connector Pin Height Inspection

Industry Background In 3C electronics manufacturing, connectors are critical components for signal transmission. The height consistency of connector pins directly affects insertion force, contact resistance, and long-term reliability. As electronic products trend toward miniaturization and high density, pin pitch decreases and height tolerances become stricter. Traditional contact measurement methods are inefficient and may damage pins, failing to meet the demand for 100% online inspection. Therefore, non-contact laser displacement sensors have become the ideal choice for connector pin height measurement.

Inspection Requirements Object: Connector pins (metal, possibly gold, tin, or nickel plated) Parameters: Pin height, height difference, flatness, coplanarity Accuracy: Repeatability better than 1 μm, linearity error less than ±5 μm Speed: Sampling frequency no less than 10 kHz to match production line cycle time Environment: Resistance to ambient light, vibration, and temperature variation Measurement Challenges Small dimensions: Pin width often less than 0.3 mm, requiring small spot size and precise positioning. Highly reflective surfaces: Metal pins cause strong reflections and diffuse interference, affecting measurement stability. Dense arrangement: Adjacent pins are closely spaced, requiring avoidance of crosstalk. High-speed online inspection: Fast cycle times demand high sampling rate and real-time output.

Recommended Sensor Solution ST-P series laser displacement sensors use laser triangulation for non-contact measurement, offering high precision, high speed, and multiple interface options. Based on pin size and accuracy requirements, the following models are recommended: Model | Reference Distance | Measurement Range | Repeatability | Linearity Error | Application ST-P25 | 25 mm | ±1 mm | 0.05 μm | <±0.6 μm | Ultra-precision pin height ST-P30 | 30 mm | ±5 mm | 0.15 μm | <±3 μm | High-precision coplanarity ST-P50 | 50 mm | ±10 mm | 0.25 μm | <±4 μm | General connector inspection ST-P80 | 80 mm | ±15 mm | 0.5 μm | <±6 μm | Larger standoff distance The sensors feature a maximum sampling frequency of 160 kHz and support Ethernet, RS485, analog, and IO outputs, enabling flexible integration with PLCs, host computers, or vision systems.

Implementation Mounting Methods Fixed mounting: Sensor positioned vertically above the pin array, fixed to a bracket on the production line, suitable for continuous online inspection. Scanning mounting: Sensor mounted on an XY motion stage, scanning pins sequentially, suitable for offline sampling or small batches. Measurement Process Connector arrives at the inspection station via conveyor, triggering sensor sampling. Sensor measures each pin height sequentially; data is transmitted via Ethernet or RS485 to the host computer in real time. Host software calculates height difference, flatness, etc., compares with tolerances, and outputs OK/NG signals. Defective parts are marked or rejected; good parts proceed to the next process.

Signal Output Options Analog output: 4-20 mA or 0-10 V, directly connected to PLC analog module for real-time height feedback. Digital output: IO discrete signals for alarm or sorting. Communication interface: Ethernet or RS485 supporting Modbus TCP/RTU for easy system integration.

Selection Considerations Measurement range and accuracy: Choose model based on pin height tolerance. ST-P25 offers highest precision; ST-P30 and ST-P50 balance accuracy and range. Spot size: For narrow pins, select a model with small spot diameter to avoid adjacent pin interference. Sampling frequency: For fast cycle times, choose high-frequency models (e.g., 160 kHz). Surface reflectivity: For highly reflective metal surfaces, verify if the sensor has anti-glare algorithms or adjustable gain; sample testing is recommended. Environmental adaptability: Consider vibration, temperature, and dust; select appropriate protection rating.

Application Value Improved inspection efficiency: Non-contact measurement enables thousands of pins per second, achieving 100% online inspection. Ensured product quality: High-precision measurement ensures pin height consistency, reducing defect rates. Reduced labor cost: Automated inspection replaces manual visual or contact measurement. Data traceability: Real-time data upload facilitates quality analysis and process improvement.

Precautions Sample testing: Due to variations in pin surface reflectivity, color, and plating, conduct sample testing with actual parts to verify stability and accuracy before deployment. Mounting angle: Keep the sensor perpendicular to the measured surface; excessive tilt increases measurement error. Ambient light interference: Strong ambient light may affect measurements; consider using a light shield or sensor with optical filter. Vibration isolation: Ensure the mounting bracket is rigid; add vibration dampeners if necessary to avoid reading fluctuations.

Regular calibration: Calibrate the sensor periodically using a standard to maintain long-term accuracy. The above solution is based on typical applications of ST-P series laser displacement sensors in connector pin height inspection. Specific selection should be confirmed according to actual working conditions and accuracy requirements.