A note on the fabrication methods of flexible ultra micro-perforated panels

Micro-perforated panel (MPP) absorber has been studied and developed for decades and is becoming more and more popular in an environment protective society. Although the traditional MPPs are rigid, the research results in recent years have indicated that flexible MPPs with ultra-micro perforations of diameter less than 100 μm (ultra-MPPs) may have great potential to become a wideband sound absorber in high frequency range. However, it is a great challenge for both traditional mechanical methods and micro-fabrication technology to fabricate so small holes directly on flexible materials, which greatly limits the development of flexible ultra-MPPs. Therefore a new technical solution is strongly desired. To meet this demand, a new process, based on mold manufacturing technology and casting technology, is developed, and the key and specific process steps are presented in this paper.