A modified form of sprue gate is also used on underfeed moulds and runnerless moulds.

在点浇口形模具或模具中也用到另一种形主。

The grooved head of the sprue puller creates an effective undercut which is used to pull the sprue, or secondary sprues in underfeed designs.

主拉料杆头槽形成了一个有效底切，可以用来拉出主或者是下进料设计中二级主。