Plastic bottle cap: the factors that affect the size and processing quality have these respectively

Update:28 Oct 2020

Plastic bottle cap can be seen everywhere in our life. The sealing device used in most drinks is still it, which has been popular for more than ten years. However, in the process of processing, there are many factors that will affect its processing effect, such as the size and the processing quality. The factors that affect the size are pressure and time, mold temperature Temperature of raw material, weight of bottle cap, etc. So what are the factors that affect the quality of plastic bottle cap processing? Let's learn about it in the article!

The factors influencing the size of plastic bottle cap are as follows
1. Holding pressure and time
Through the analysis of test data, with the increase of holding time, the weight of bottle cap increases gradually, which leads to the size becoming larger. Similarly, with the increase of the packing pressure, the weight of the bottle cap will increase with the increase of the weight of the raw material in the same time, which will cause the size to become larger. In the above process, the density of the cap remains unchanged.
2. Mold temperature
The higher the mold temperature is, the worse the cooling effect of the bottle cap in the mold is under the same cooling time. The higher the temperature of the bottle cap is, the smaller the cap size is after thermal expansion and cold contraction.
3. Raw material temperature
With the increase of raw material temperature, if the cooling time remains unchanged, the bottle cap temperature will be higher. After natural cooling after demoulding, the size will be smaller due to the principle of thermal expansion and cold contraction. The injection molding equipment parameters corresponding to raw material temperature include screw temperature and mold temperature.
4. Cap weight
A large number of experimental data show that with the increase of the weight of the cap, the temperature of the cap will increase and the size of the cap will decrease. But theoretically, the larger cap size will be obtained by increasing the cap weight. So the effect of weight on size depends on how much weight is added and how much temperature changes, because the two counteract each other.

The factors affecting the quality of plastic bottle cap processing are as follows
1. If the filling pressure is too high and the filling speed is too fast, the die will be expanded and the overflow will occur. Therefore, the filling pressure and speed should be reduced appropriately, or the melting temperature should be reduced to increase the viscosity.
2. If the packing pressure is too high, the plastic will be forced to condense, and the residual stress will be large, which will reduce the strength and may cause overflow. Therefore, the packing pressure should be appropriately reduced.
3. If the tube temperature or hot runner temperature is too high, the viscosity of the melt will decrease and the fluidity will be too good. Therefore, the temperature or injection pressure can be appropriately reduced.
4. If the mold temperature is too high, it will not only have sharp edges, but also product deformation and other defects. We can reduce the mold temperature by lowering the temperature of the chiller or increasing the waterway.
5. If the injection switch position is improper, increase the switch position or decrease the dose.