The striking metallic finish on plastic packaging, lighting and automotive trim is created by vacuum metalising – see also TieGuan Yin Tea packaging. It is used to produce a bright and reflective appearance on three-dimensional parts and is less expensive than manufacturing the same part from solid metal.
The process is carried out in a vacuum chamber, where almost pure aluminium is vaporised and condenses on the surface of the parts. It is locked-in and protected by a topcoat, which can be coloured to create the look of gold, silver, chrome, anodised aluminium (see also bright anodised aluminium) or other metal.
Image from The Manufacturing Guides