DELIGHT - Elastomer components with sensor functionality

Development of an Industrial Manufacturing Technology for Elastomer Sensors

Digitalization in the context of Industry 4.0 requires a high density of sensors integrated into machines and systems. In the DELIGHT project, we are developing an industrial manufacturing technology for elastomer sensors that can be integrated into load-bearing elastomer components such as machine bearings or couplings. The sensors are based on the patented capacitive Delta-C© technology and measure both static and dynamic forces. This enables, for example, the monitoring of machines, the detection of overloads, and the extension of maintenance intervals.

Delta-C© Technology

The Delta-C© technology, developed and patented at Fraunhofer LBF, uses structured metal electrodes with a dielectric elastomer between them. When a load is applied, the elastomer deforms and is pressed into the structure of the electrodes, causing a change in electrical capacitance proportional to the load. Sensors based on this concept are cost-effective and environmentally friendly, as they consist solely of elastomer and metal and do not use critical materials such as rare earths or piezoceramics. They can be used across a wide frequency range and are resistant to overloads.

delight-elastomerintegrierter-sensor
delight-elastomerintegrierter-sensor
Elastomerintegrierte Sensoren

Development of a Scalable Manufacturing Technology

Before the project began, a major obstacle to the industrial application of this technology was the high cost of producing etched metal electrodes in small quantities, as well as the labor-intensive and difficult-to-replicate manual fabrication of individual sensor elements. The project therefore developed an industrially viable manufacturing process for structured metal electrodes made from wire mesh and metal foil, which are bonded using a roll-to-roll process and smoothed in a straightening rolling process. In addition, a production line was implemented that enables the assembly of a laminated composite in an automated closed-loop process, in which liquid silicone is applied layer by layer with a squeegee to the desired thickness and cured, and the electrodes are then placed using a pick-and-place robot. In combination with a subsequent end-of-line test of the sensor properties, the process and design parameters were optimized, thereby improving the performance of the sensor elements and increasing the reproducibility of their properties.

Integration into Elastomer Components

The sensor elements produced using this process were subsequently integrated into various elastomer components as prototypes. This made it possible to develop sensor-integrated machine mounts and couplings, which were ultimately tested in a real-world operating environment in collaboration with the participating industry partners. The experience gained here shows that integrating sensor elements into elastomer components requires innovative approaches and thorough preliminary investigations to achieve the desired functional results and overcome the challenges of each specific application.

Validated and Scalable Manufacturing Technology for Delta-C© Sensors

In the DELIGHT research project, a production line at Fraunhofer LBF is therefore being retrofitted to provide a validated and scalable manufacturing technology for Delta-C© sensors in the load range from 10 N to 6 kN. The sensor elements are assembled step-by-step on a rigid or flexible substrate, onto which the elastomer is alternately spread and the electrodes positioned. Depending on the required sensor properties, this creates a layered composite that can be integrated into industrial elastomer components. The previously used precision-etched—and thus cost-intensive—structured metal electrodes were replaced in the manufacturing process with a cost-effective metal mesh laminated on one side. Automated manufacturing also improved the reproducibility of the sensor elements, enabling structured investigations into various design and manufacturing parameters.

At the conclusion of the project, the technology is scheduled to be demonstrated in functionally integrated elastomer components in real-world operating environments.

Funding Bodies and Partners

  • AiF Research Network for Small and Medium-Sized Enterprises
  • German Federal Ministry for Economic Affairs and Climate Action (BMWK)

The DELTA-C sensor technology is based on this patent: Kaal, W.; Herold, S.; Melz, T.: Electroactive Elastomer Transducer, Patent EP 2630674

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