Web Tension Monitoring with Ultrasonic Sensors

To achieve consistent material flow, ultrasonic sensors are used for web tension feedback in thermoforming, paper converting, and metal stamping processes. By observing either the sag level of a free-hanging loop between the supply spool and the production station, or a dancer arm’s position, the system controller creates adjustments on-the fly to get a precise, repeatable final product.

Web Tension Monitoring Application

Web Tension Monitoring with Ultrasonic Sensors
Web Tension Monitoring with Ultrasonic Sensors

The goal is a reliable solution for loop tension monitoring. Keeping the proper tension is essential for retaining a reliable feed speed and material flow. This consistency ensures the same high quality which is crucial for stamping and metal forming processes.

A PEPPERL+FUCHS ultrasonic sensor from is placed above the center of the loop. The acoustic pulse released by the sensor meets the loop at a perpendicular angle. The device can either continuously monitor the distance to the loop, or signal when defined limits are reached through means of two switching outputs.

The control parameters can be configured quickly and easily using the programming buttons or parameterization software.

Advantages of Ultrasonic Sensors

In some cases, an ultrasonic sensor is better suited for an application than an optic-based sensor. For example, ultrasonic sensors are perfect when working in a dusty environment, different-colored or clear objects, lateral movements of the material loop, and changing target size or materials.  As a bonus, ultrasonic sensors give you the option of signaling that the loop has reached its high/low limits.