| 摘要 |
<p>An apparatus and method for injection molding includes a first melt passage (122) for the flow of a first material (200), and a second melt passage (84') in communication with the first melt passage (122) for the flow of a second material (300). The apparatus and method for injection molding also includes a valve pin (110') that passes through the second melt passage (84'). The valve pin (110') has a first portion (810) allowing the flow of the second material (300), but not the first material (200), through the second melt passage (84'), and a second portion (812) restricting the flow of the first material (200) and the second material (300) through the second melt passage (84'). The valve pin (110') may also be used to restrict material flow from a melt channel (78) into a cavity (36). In addition, a back-flow control valve (808) may be combined with a melt passage (84') of the apparatus and method for injection molding. The back-flow control valve (808) has a first portion (810) for permitting flow of material through the melt passage (84'), and a second portion (812) for restricting flow of material through the melt passage (84').</p> |
