The stretching rod is not in the center of the preform;the blowing hole is not in the right position, the hole size is different; the stretching ratio is too low or the blowing ratio is too small;the preform does not rotate during heating; the preform wall thickness is not uniform or the injection preofrm density is not uniform.

Methods

Cause

The temperature is not enough；the delay stretching time is too long，The stretch ratio is too large；the bottom of the bottle is too thin；stretching rod head too sharp .

Methods