Proportional Switching
Thanks to NEXIPAL®, an actuator cannot only be switched on and off, but can also achieve all states in between. A stroke of only 20% or 80% can be realized just as well as no stroke at all or a 100% one.
Robots with muscles like humans. Hand prosthetics with a fine touch thanks to artificial muscles. Shelves that report when they need refilling. Touchscreens that can be operated without eye contact. All a long way off? Not for much longer: thanks to innovative EAP technology, such visions are rapidly becoming reality.
EAP stands for “electroactive polymers” – thus polymers that change their shape when exposed to electric current. WACKER is a leader in EAP technology. As of 2022, the company will be launching innovative EAP laminates under its NEXIPAL® trademark that open up fascinating possibilities in the areas of actuators and sensors.
NEXIPAL® laminates consist of several layers of ultrathin ELASTOSIL® silicone film that WACKER manufactures as roll stock. The film thickness is between 20 µm – thinner than a human hair – and 400 µm. For the film to execute and/or measure movements, it is first coated with conductive electrodes and subsequently laminated layer by layer.
In actuator applications, laminates made with NEXIPAL® convert electrical voltage into mechanical work. Each layer of the laminate film, also known as the dielectric layer, is embedded between two flexible electrodes. When voltage is applied, the individual electrodes are alternately positively and negatively charged. The positive and negative charge carriers of the electrodes then attract one another. This compresses the silicone film, causing it to expand in length – resulting in voltage-induced movement. When the voltage is switched off, the silicone film returns to its original state. This process can be repeated millions of times at high frequency.
Mechanical influences change the electrical capacity of the laminate. Electroactive polymer laminates are therefore also suitable for use as capacitive sensors, such as in intelligent textiles that measure the body’s movements to support training, diagnosis and rehabilitation. Touchscreens equipped with NEXIPAL® can execute vibrations and haptic signals to simulate keys that can be recognized and operated by touch alone and without eye contact – practical for the cockpit in automotive engineering, for example.
NEXIPAL® Sense and NEXIPAL® Act can revolutionize numerous applications in sensor and actuator technology, because EAP actuators and sensors offer a range of advantages over solenoids:
Thanks to NEXIPAL®, an actuator cannot only be switched on and off, but can also achieve all states in between. A stroke of only 20% or 80% can be realized just as well as no stroke at all or a 100% one.
Strokes of several millimeters to a few centimeters can be achieved, depending on the component’s design.
Electroactive polymers can act as actuator and capacitive sensor at the same time. They are not only able to detect extension, compression or other deformations, but can also respond to it with movement.
An actuator with NEXIPAL® laminates works at an extremely high frequency: it can contract several thousand times per second and return to its original state.
NEXIPAL® laminates consist of ultrathin layers of ELASTOSIL® Film. Unlike solenoid, they are completely silent.
Compared to a solenoid valve, microthin NEXIPAL® laminates exhibit a weight reduction of 20% to 40% depending on the component’s design.
EAP actuators consist of elastic film with excellent recovery. They can be deformed without losing their function. This is not possible for solenoids due to their metal parts.
Thanks to its electrostatic principle of operation, NEXIPAL® technology is extremely energy saving compared to conventional solutions. Depending on the design, EAP actuators require up to 99.5% less energy than solenoid valves.
ELASTOSIL® Film is a completely novel development from WACKER. This ultrathin, high-precision film of crosslinked silicone rubber is available in various thicknesses of 20 μm to 400 μm as roll stock and is manufactured under cleanroom condition entirely without solvents. ELASTOSIL® Film for silicones sensors and actuators enables unique functionality i.e. for smart textiles and other intelligent applications in the robotics, medical and lifestyle sectors.
Visit our product portal to learn more about NEXIPAL® and its applications in sensors and actuators.
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