Unit (4) for molding preforms (2) that each have a body (15) and a neck (17) extending the body (15), this unit (4) including: a frame (19),a mold holder (27) secured to the frame (19) and carrying at least one mold body (29) having the impression of the body (15) of the preform (2); mobile equipment (60) including a carriage (61) and a core holder (62) carrying at least one primary core (64A) and one secondary core (64B), the carriage (61) being mounted so as to be movable with respect to the frame (19) between a molding position and a demolding position, this core holder (62) being rotatable with respect to the carriage (61), in the demolding position of the latter, about a rotation axis parallel to the molding axis in order to transpose the cores (64A, 64B).

A mold of a forming tool capable to be used for resin transfer molding processes or injecting molding processes, wherein an inner surface of the mold, which is adapted to limit on one side a forming tool cavity for a product to be fabricated, has an integral surface section which is adapted be moved relatively to adjacent surface areas in a demolding direction. Also a forming tool having such a mold and a method for demolding in which an integral inner surface section acts as membrane and is moved inside the cavity to push the product out of the mold.

Unit (4) for molding preforms (2) that each have a body (15) and a neck (17) extending the body (15), this unit (4) including: a frame (19), a mold holder (27) secured to the frame (19) and carrying at least one mold body (29) having the impression of the body (15) of the preform (2); mobile equipment (60) including a carriage (61) and a core holder (62) carrying at least one primary core (64A) and one secondary core (64B), the carriage (61) being mounted so as to be movable with respect to the frame (19) between a molding position and a demolding position, this core holder (62) being rotatable with respect to the carriage (61), in the demolding position of the latter, about a rotation axis parallel to the molding axis in order to transpose the cores (64A, 64B).