Which process uses hot air to conform heated plastic to a mould?

Blow moulding is the correct answer because it specifically involves the process of using hot air to expand heated plastic, allowing it to take the shape of a mould. In blow moulding, a pre-formed plastic tube, known as a parison, is placed in a mould. Air is then blown into this tube, causing it to expand and conform to the interior walls of the mould. This process is especially useful for creating hollow objects, such as bottles, containers, and other similar items.

In contrast, injection moulding involves injecting molten plastic directly into a mould under pressure, which is a different method that does not utilize hot air for conforming plastic. Turning refers to a machining process used primarily for shaping materials by rotating them against cutting tools, and abrading involves removing material through friction. Neither of these processes uses hot air to shape plastic, making blow moulding the only suitable option for the question.