METHOD OF MAKING MOLDED ARTICLE, TOOLING AND TUBULAR ARTICLE Russian patent published in 2019 - IPC B21D51/16 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to forming of curved products of closed tubular shape by stamping from metal plate. At first step, metal plate is used to produce article with U-section with lower part straightly passing in lengthwise direction. At the second stage of molding, the U-shaped item is bent in lengthwise direction to allow projection of its lower part inside. And at the third stage, curved article with U-shaped cross-section is provided with closed cross-section.

EFFECT: higher quality of product due to gradual molding, which suppresses occurrence of formation defects.

1 cl, 1 tbl, 14 dwg