Solve the defects of automatic blow molding machine

2019-04-30 17:15:08

Too much liquid level drops after filling

symptom:
The user requested that once the PET container was filled, the container itself changed as little as possible. This change is called excessive creep.
diagnosis:
The container should be used at a lower temperature during the blowing process. If the temperature is too high, there is no pearl on the container.
The maximum two-way stretching is required to make the container insufficient in strength to resist expansion after filling, and the bottle made at high temperature is easily ruptured after being expanded.
prescription:
Conventionally, fully automatic blow molding machines should generally exhibit some visible pearlescence at the end. When starting the equipment, the temperature of each heating furnace should be accurately set to avoid overheating or overcooling.


burst
symptom:
Unexplained ruptures often occur at the bottom of the bottle or near the bottom, and some break the transition zone from thick to thin.
diagnosis:
The cause may be as follows:
1. The material failed to reach the limit of its natural stretch during the blowing process. This causes the container to undergo a radial change (creep) after filling, causing the bottom to crack.
2. The natural wrinkles at the bottom may cause a burst during filling, or burst after the bottle has warmed for a while.
3, too thin bottle bottom is also very easy to burst.
4, the bottom of the bottom of the bottle will also increase the occurrence of accidents.
5. When the value of I.V. is low, the bottle expands after filling, causing a burst.
6. If the bottom transition zone is over-damaged after molding, it will also cause stress damage.
7. The choice of grease for the filling machine is incorrect.


Molding line flattening
symptom:
The mold clamping line of the automatic blow molding machine in the vertical direction is flat, and there is a tendency to separate the mold at the blowing pressure.
diagnosis:
Since the bottle is blown in all directions, the applied air pressure will run outward from the air vent hole (exhaust hole) of the mold line, and when the excess gas cannot be discharged in time, the pressure gas has a tendency to separate the Harvard mold. The thin layer of material constituting the wall of the bottle is blown into the vent hole to cause clogging.
prescription:
1) Accurately set the gap of the mold so that the gap cannot be too large under the condition of adding air pressure.
2) Check the wear of the mold positioning pin and bushing.
3) When the high stick is blowing, the air supply is slower, and the flow of the high pressure valve controller is adjusted. Unfortunately, doing so reduces the effective cooling time of the mold.
4) Drill several air-permeable holes along the mold line, with a hole diameter of 0.5mm-0.7mm.


Bottom wrinkle
symptom:
The wrinkles may be very slight and are brought to the bottle by the bottom of the blank, which may be in the bottle or outside the bottle. This bottle is easily broken after filling the machine.
diagnosis:
The external wrinkles are usually formed because the blowing pressure 1 is not enough or not at all, so that the stretching pushes too much material to the bottom, the preform end is overheated, or the blowing pressure 1 after the start of stretching is too late. The internal wrinkles will be formed, because the hot preforms stick together, I think that the damaged surface will also cause the bottle to rupture after being opened.
prescription:
1) Make sure that the timing of the blown bottle 1 on each mold is consistent, that the three-way valve is not tightened, and that the return valve is misaligned.
2) Do not overheat the end of the preform.
3) Make sure that the delay (distance) from the start of stretching to the entry of blowing 1 is not too long.