(1).The reason is that the injection assembly, in particular the return checking ring is broken, unable to prevent the melting plastics from flowing backward during the injection, leading to the rotation of the screw.

 (1). 注射部份组合尤其是止逆环损坏，不能阻止注射时熔溶塑料向后流动，引致螺杆转动。

 (2). 预塑油马达是否损坏。

(2).whether the pre plastic oil motor is damaged.

(3). 单向阀是否损坏。

(3). whether the check valve is damaged.

(4). 电气是否有误动作。

(4).whether there is electrical error.