The invention discloses a manufacturing process of a
metal spiral cover, and particularly relates to a manufacturing process of a tinplate spiral cover. The manufacturing process sequentially comprises the following steps of selecting tinplate, carrying out tinplate painting and printing,
cutting tinplate subjected to painting and printing into small sheets / stretching,
cutting stretched left material, carrying out opening end inward pre-
curling, carrying out opening end inward edge
curling, carrying out curled edge pressing, carrying out thread pressing, carrying out expansion one or more times according to the final shape structure of the cover, and installing a sealing rubber
gasket in the cover. According to the manufacturing process, when the cover structure is formed, when the sheetmaterial is stretched into a circular
barrel shape, the transition part between the cover bottom and the cover body forms a large circular angle to play a role in buffering subsequent
forming processes, meanwhile, the follow-up cover structure is formed according to the final shape of the cover through one-time or multiple-
time step-by-step molding, so that corresponding appearance defects are avoided, meanwhile, the defects that the subsequent deformation degree is relatively large and the edge of the cover is cracked are avoided, in the forming process of a
screw thread, the four proceduresof edge pre-
curling, edge curling, curled edge pressing and
screw thread pressing are adopted, the edge of the cover opening is smooth and tidy after
screw thread is formed, the shape of the screw thread is uniform, the sealing performance is good, and the matching degree is high.