Views: 8 Author: Site Editor Publish Time: 2021-05-03 Origin: Site
The blow molding process of the extrusion blow molding machine is a bidirectional stretching process, and the chains are bidirectionally extended, oriented and arranged to improve stretching, tensile strength, impact strength and air tightness.In the production process, it is necessary to control the stretch-inflation ratio to avoid quality problems.
The blow molding process can be divided into three processes: stretching, primary blowing, and secondary blowing. The three action times are short, but they must be well coordinated, especially in the stretching and primary blowing stages, which determine the overall distribution of the material. The final product is good or bad, so it is necessary to adjust the stretching start timing, stretching speed, pre-blowing start and end timing.
More common blow molding machine technical problems:
1. Thick top and thin 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 above.
3. There are wrinkles under the bottleneck: the pre-blowing is too late or the pre-blowing pressure is too low, or the blank cooling here is not good.
4. White bottom: the preform is too cold, too stretched, 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 bottom temperature 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 is too small.
7. The whole bottle is turbid: opaque and insufficient cooling.
8. Partial whiteness: Excessive stretching, the temperature here is too low, or the pre-blowing is too early, or the stretch rod is hit.
9. Eccentricity of the bottom of the bottle: It may be related to the temperature of the preform, stretching, pre-blowing, high-pressure blowing, etc. Reduce the temperature of the preform, speed up the drawing speed, check the gap between the tie rod head and the bottom mold, postpone the pre-blowing, reduce the pre-blowing pressure, postpone the high-pressure blowing, and check whether the preform is eccentric.
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