| 摘要 |
<p>A metal die for injection moulding suitable for making synthetic resin cast articles which need to have an isotropic structure, such as lenses and prisms, has a first and a second gate (3, 4) located between a runner (2) and a cavity (1). The first gate (3), the middle part of which is a narrow passage (5), is connected to the second gate (4) through a passage having a cross section smaller than that of the runner (2), and the second gate (4) is connected through a gradually extending passage to cavity (1) having the shape of the shoulder portion of a coat-hanger. </p> |
