A survey of microfabrication techniques for use in stirling engine regenerators

Regenerators of the next generation Stirling engine may incorporate microscale features for improved heat transfer and fluid flow characteristics. Examples of microscale geometries under consideration include hexagonal flow passages or passages between plates with approximately 15μm thick walls and 125μm spacings. These microscale features can be produced by technologies that are currently used to produce electronic devices and microclcctromcchanical systems (MEMS). In this paper, the challenges associated with producing large scale parts (i.e. the size of a regenerator) with microscale features are discussed and a set of process requirements are identified. Various manufacturing processes currently available are described and evaluated relative to the process requirements. Future directions in microscale manufacturing are presented.