Apple Inc.
Etching for bonding polymer material to a metal surface

Abstract:

This application relates to a composite part that can include a non-metal layer having attachment features, and a metal part that is joined with the non-metal layer. The metal part can include a plurality of interlocking structures that are disposed at an external surface of the metal part, where each of the interlocking structures can include an opening characterized as having a first width, and an undercut region, where the opening leads into the undercut region, and the undercut region is characterized as having a second width that is greater than the first width such that the undercut region captures and retains one of the attachment features of the non-metal layer.