METHOD FOR MAKING PRODUCTS WITH INNER HELICAL RIBS Russian patent published in 2001 - IPC

FIELD: plastic metal working, possibly manufacture of hollow cylindrical articles with inner helical ribs for heat exchanging apparatuses, mainly with two-phase flows. SUBSTANCE: method comprises steps of deforming tubular blank and rolling it around shaped rotating mandrel placed inside it in order to radially deform blank by means of power expanding head with planetary rotation of pressing members at simultaneous radial motion of blank. Revolution number of shaped mandrel rotating in the same direction with expanding head is maintained equal to revolution number of power expanding head. Working portion of shaped mandrel is in the form of truncated ellipsoid having cross section in the form of symmetrical polyhedron with inlet and calibrating zones and with face number equal to that of pressing members. Axial feed of blank by one revolution of mandrel Smm/rev is selected equal to stroke of profile of rib helix. Adjustment of rib profile by height size is realized at radial reduction of blank by means of adjusted pressing members of power expanding head. EFFECT: enlarged manufacturing possibilities of method. 2 cl, 5 dwg