Skin pack, or skin packaging, is a type of carded packaging where a product is placed on a piece of paperboard or in trays, and a thin sheet of transparent plastic is placed over the product and paperboard or trays. The printed paperboard/tray usually has a heat-seal coating. The plastic film (LDPE, PVC, ionomer, etc.) is softened by heat and draped over the product on the card/tray. Vacuum is sometimes used to assist a firm fit. The film bonds to the heat-seal coating on the paperboard. The skin-packed piece then may need to be cut into individual units.

The basic function of a thermoforming packaging machine is that the bottom film is heated and shaped by the forming tool. The shaped film pocket is transported to the loading zone of the machine where the product is loaded into the cell pocket. The filled film cell is transported to the sealing station, where vacuum and/or a modified atmosphere is applied and the pack is sealed with a top film. The package is then transported further and cut to size, after which it eventually leaves the machine.