What are the reasons for the fragility of plastic bottles? From which aspects

Generally speaking, the fragile plastic bottles are mainly caused by five aspects: mold, equipment, raw materials, process and product design. The following follows the medicinal plastic bottle manufacturers to learn more about:

First, the plastic bottle mold

1. If the gate is too small, consider adjusting the gate size or adding an auxiliary gate.

2. If the runner is too small or improperly configured, it should be balanced as much as possible or increase the size of the runner.

3, poor mold structure caused abnormal injection cycle.

Second, the equipment aspect

1. There are dead corners or obstacles in the barrel, which can easily promote the degradation of the melt.

2. The plasticizing capacity of the machine is too small, the plastic is not plasticized in the barrel; the plasticizing capacity of the machine is too large, the plastic is heated and sheared for too long in the barrel, the plastic is easy to age, and the product becomes brittle. .

3. The ejector unit is inclined or unbalanced, and the top sectional area is small or improperly distributed.

Third, raw materials

1. When the raw materials are mixed with other impurities or doped with an inappropriate or excessive amount of solvent or other additives.

2. Some plastics, such as ABS, will undergo catalytic cracking reaction with water vapor under the damp condition, causing large strain on the workpiece.

3. If the number of plastic regenerations is too high or the content of recycled materials is too high, or the heating time in the barrel is too long, the parts will be brittle.

4. The quality of the plastic itself is not good. For example, the molecular weight distribution is large, and the composition of the uneven structure containing rigid molecular chains is too large; or it is contaminated by other plastics, contaminated with bad additives, and contaminated with dust impurities. 

Fourth, the process aspects

1. The temperature of the barrel and nozzle is too low to increase it. If the material is easily degraded, the temperature of the barrel and nozzle should be increased.

2. Reduce the pre-plastic back pressure and speed of the screw to make the material slightly loose and reduce the degradation of the plastic due to shearing and overheating.

3, the mold temperature is too high, the demoulding is difficult; the mold temperature is too low, the plastic is prematurely cooled, the fusion joint is poorly fused, and it is easy to crack, especially for high melting point plastics such as polycarbonate.

4. The cavity core should have a proper draft angle. When the core is difficult to demould, it is necessary to increase the cavity temperature and shorten the cooling time; when the cavity is difficult to remove, the cavity temperature should be lowered and the cooling time should be prolonged.

5, as little as possible to use metal inserts, such as polystyrene such as brittle hot and cold specific plastic, can not be added to the insert injection molding.

Five, product design

1. The product has sharp corners, notches or areas with large differences in thickness which are prone to stress cracking.

2. The product design is too thin or too hollow.