 Electrical insulation paper is often baked dry, without vacuum, before being placed into insulating oil, because even small amounts of water degrade the insulating performance of oil.In various physics and vacuum device engineering, such as particle accelerators, semiconductor fabrication, and vacuum tubes, bake-out is a manufacturing process, the period of time when a part or device is placed in a vacuum chamber (or its operating vacuum state, for devices which operate in a vacuum) and heated, usually by built-in heaters.This drives off gases, which are removed by continued operation of the vacuum pump.