Dynamic-Enhanced Macroscopic Paraffin Wax Phase Change Actuators as a Method of Process Stabilization

Modern production chains are subject to constantly growing demands for agility, adaptability, variant diversity and robustness. These demands can push even sophisticated systems to their limits. For product validation during development, as well as for disturbance compensation, the macroscopic paraffin wax phase change actuator (PCA) is a proven tool. The PCAs also operate in highly rigid systems with achievable actuating forces of more than 85 N per square millimeter of effective actuator area. In addition, the particularly compact housing offers high integration capability. However, the low dynamics due to the low thermal conductivity of the paraffin wax is challenging. Response times of more than 20 min are often not acceptable to counteract process fluctuations, e.g. due to material influences. Therefore, performance improvements for the PCA are presented that use internal structures to significantly reduce thermal paths. As a result, the response time can be drastically reduced and additionally the actuator force is increased by 60%. Furthermore, the influence of additives in the paraffin wax is discussed.