This operation consists in separating the surrounding flash from the article. Normally this is carried out by cryogenic machines. Articles with big dimensions and critical angles are deflashed by hand.
The cryogenic deflashing permits the separation through reciprocal impacts of the articles at very low temperatures obtained by the expansion of liquid nitrogen (-80°C -150°C) into rotating containers.
Sometimes this separation is supported by the use of steel spheres, which shorten the process.