Summary

Un fabricante de tarjetas madre para PC utiliza detección de presencia inmediatamente después de la soldadura por refusión para activar una operación posterior. Un sensor inductivo de larga distancia se monta sobre el transportador de salida del horno de refusión y detecta cada tarjeta madre a medida que sale del horno. El sistema de control del cliente acepta la salida del sensor NPN, iniciando la siguiente etapa del proceso.

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Valor al cliente

  • La producción ininterrumpida, así como la detección de la placa de circuito es altamente confiable
  • Costes de reemplazos mínimos como resultado de la larga vida útil del sensor
  • Bajo riesgo de daños térmicos o mecánicos debido a la distancia de operación extendida

Ventajas específicas de los productos

  • El rendimiento del sensor no se ve afectado por temperaturas elevadas
  • La tecnología Condist® de la familia Extra Distance ofrece las mejores distancias operativas de su clase.
  • Rango de detección extendido ≤ 10mm
  • Sensor inductivo robusto con carcasa metálica

Aplicación cliente

During manufacture of PC motherboards, reflow soldering is used to secure components in place on printed circuit boards. Following assembly, boards are conveyed into a reflow oven, where the temperature increases progressively to achieve a predetermined thermal profile, melting the solder paste on the boards.

As each board leaves the oven, a sensor must trigger the customer’s control system and activate a transfer mechanism, moving the board automatically to the next process stage.

The ambient temperature immediately adjacent to the oven may reach 80°C (176°F), which has caused unacceptable rates of sensor failure in the past. Sensors must operate continuously in this environment with ultra-high reliability.

Extended sensing distances are highly desirable for this application as several types of motherboard, each with different component heights, pass through the oven. Long-distance sensing does not require the sensor to be positioned in close proximity to hot boards.

Solución al cliente

Contrinex inductive sensors from the Extra Distance family (500 series) are ideal for this application.  Condist® technology delivers best-in-class operating distances and sensors have a continuous rating to 70°C (158°F). Trials confirmed highly stable performance even in the elevated ambient temperatures around the reflow oven. Vacuum-encapsulated electronics ensure excellent resistance to thermal shock and vibration.

Extra Distance sensors are mounted vertically on steel brackets attached to the exterior of the reflow ovens, and sense the presence of each motherboard as it passes beneath the sensing face. The operating distance is set at 10mm, eliminating the risk of collision with components on the board, and an M12-threaded metal housing allows easy positional adjustment when necessary.

Extra Distance sensors with an industry-standard NPN normally-open configuration connect with the customer’s control system via a flexible PVC sheathed cable. No additional electrical or mechanical protection is required in spite of the adverse operating conditions.

Previously, sensors from other manufacturers did not detect boards reliably and had unacceptably short service lives, causing frequent interruptions to production. Sensor replacement costs were excessive. Contrinex inductive sensors have been reliable and long-lived, providing a professional sensing solution with an attractive total cost of ownership.

Products used

Product nameDatasheet

DW-AD-511-M12

320-520-050
Operating distance:
10 mm
Housing size/Mounting:
M12, Non-embeddable
Polarity/Output:
NPN, Normally open (NO)
Connection type:
PVC, 2 m, 3 wire
Download datasheet