Reliable monitoring of material discharge at screw dosing units presents a challenge in plastics processing that has so far only been inadequately addressed.

With volumetric and gravimetric systems, malfunctions such as bridging in the hopper, missing material or mechanical misalignments can prevent material from being conveyed – without this being immediately detected.

Even when using gravimetric measurement routines, the necessary verification of the measured values introduces a time lag. This lag depends on the setpoint: the smaller the setpoint, the greater the delay.
Therefore, several minutes can pass before it is detected that no material is being discharged and the control system issues a corresponding error message – a significant quality risk in the ongoing production process.

A newly developed solution enables real-time monitoring of material flow: The firmware, jointly developed by WOYWOD and a Swiss sensor manufacturer, utilizes advanced ultrasonic sensors to precisely monitor the material flow after dosing at the dispenser's outlet.

The ultrasonic sensor is capable of handling various types of granules (in terms of shape, colour, grain size and material quantity). Continuous measurement verifies in real time whether material is actually being dispensed – independent of target values or the delay effects of conventional weighing systems.

For users, this offers clear advantages:

• early detection of production errors
• rapid response capabilities within the process
• reduction of downtime and defective batches
• fewer customer complaints
• enhanced process reliability and product quality

The new ultrasonic solution represents a significant step toward greater efficiency and quality in plastics processing.

Further information here