Phenomenon 1: bottle mouth expansion, bottle blowing and gas leakage
Cause: as the temperature of the surrounding space increases gradually, the cooling effect of the air flow through the oven decreases, resulting in the rise of the core rod temperature, which is transmitted to the thread area.
Solution: external cooling can be adopted to control the temperature of the thread area and mandrel when the bottle embryo passes through the oven; Adjust the position of the cooling plate so that it can better protect the threaded area of the bottle embryo. In addition, a well-designed cooling plate may be a better countermeasure.
Phenomenon 2: bottom damage
Reason: the temperature at the bottom of the bottle embryo is low. When the stretching rod pushes it towards the bottom of the mold, it forms a micro crack.
Solution: the best way is between stretching and cracking, so that the end of the bottle embryo is neither cold nor overheated. In addition, the gap between the stretching rod and the die bottom is also very important. Only the maximum necessary gap can ensure the positioning of the door.
Phenomenon 3: Transition
Cause: the problem cavity may be caused by insufficient blowing. If the preform temperature is lower and the film bubble blows more slowly, the problem will be more obvious. The lighter bottom also means that the material has reached its natural tensile limit before the whole container is formed.
Solution: ensure that all ventilation holes on the mold are not blocked; Ensure that the blowing can be completed in the shortest time, otherwise, additional cooling will be brought to PET materials during bottle blowing; Check the working condition of the circuit valve to ensure accurate positioning during blowing.
Phenomenon 4: neck bending
Cause: this problem is generally caused by mechanical operation. The excessive thickness of material on the neck causes deformation after clamping.
Solution: if the bottle neck is too thick, the bottle neck will become crooked due to the impact of mold closing; In addition, the alignment between the conveying arm and the blowing center is also one of the reasons for this problem.
Phenomenon 5: the screw at the bottle mouth is damaged
Reason: the bottle embryo is sent into the mold cavity by the conveying arm. When clamping, one side of the thread must be stressed. When the position of the conveying arm is inaccurate, when it lifts the bottle blank ring from the top of the mold, if the weather is cold, the air blowing core will press on the closed surface of the bottle blank, which will play a pressing role and will not cause damage. Unfortunately, in hot weather, the exhaust of the thread will be subjected to tensile force, because the preform is forcibly aligned by the blown air core.
Solution: ensure that the adjustment of the conveying arm is accurate; In addition, it is also related to the alignment of the mold at the blowing core site.
