| 摘要 |
A plastication screw (1) comprises a shank (2) extending along a rectilinear axis (3), a feeding region (4) to supply a product to be plasticated, a plastication region (5) placed immediately downstream of the feeding region (4), relative to a main feeding direction (S) of the product along the axis (3) of the shank (2), at least one primary thread (7) extending in a helical development around the shank (2) at least in the plastication region (5), following a predetermined winding direction (V), and at least one secondary thread (10) extending in a helical development around the shank (2) in the same way as said predetermined winding direction (V), in at least part of the plastication region (5). The primary thread (7) and the secondary thread (10) each have a varying pitch (p 1 , p 2 ). The pitch variation (p 2 ) of the secondary thread (10) is greater than the pitch variation (p 1 ) of the primary thread (7). |
