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Blow molding machine common technical problems

November 29,2022

The blow molding process of the blow molding machine is a two-way stretching process.

The chains are stretched in two directions, oriented and arranged to improve stretching, tensile, impact strength, and air tightness. The stretching and inflation should be well controlled during the production process. Avoid quality problems.

We have made a summary of the more commonblow molding machinetechnical problems. as follows;

1. Thick at the top and thin at the bottom: delay the pre-blowing time or reduce the pre-blowing pressure to reduce the air flow.
2. The bottom is thick and the top is thin: opposite to the previous one
3. There are wrinkles under the neck of the bottle: the pre-blowing is too late or the pre-blowing pressure is too low, or the billet cooling here is not good.
4. The bottom is whitish: the preform is too cold, stretched too much, pre-blowing too early or pre-blowing pressure is too high.
5. There is a magnifying glass at the bottom of the bottle: too much material at the bottom of the bottle, too late pre-blowing, and too low pre-blowing pressure.
6. There are wrinkles in the bottom of the bottle: the temperature at the bottom is too high, the cooling at the gate is not good, the pre-blowing is too late, the pre-blowing pressure is too low, and the flow rate is too small.
7. The whole bottle is turbid: opaque, not cooled enough.
8. Partial whitening: excessive stretching, the temperature here is too low, or the pre-blowing is too early, or the stretching rod is touched.
9. Bottom eccentricity: It may be related to preform temperature, stretching, pre-blowing, high-pressure blowing, etc. Lower the temperature of the preform, speed up the stretching speed, check the gap between the tie rod head and the bottom mold, delay the pre-blowing, reduce the pre-blowing pressure, delay the high-pressure blowing, and check whether the preform is eccentric.

Finally, the blow molding process can be divided into three processes: stretching, primary blowing, and secondary blowing. The final quality of blown products, so adjust the timing of stretching start, stretching speed, pre-blowing start and end timing.