Why does the surface of PP Hollow Balls need to be smooth and without middle mold lines?

Necessity of smooth surface
In applications, PP Hollow Balls usually need to contact or move with other components, such as acting as key sealing elements in sealing valves. If the surface of the ball is not smooth, friction will increase, resulting in increased wear of components and shortened service life. A smooth surface can effectively reduce the friction coefficient, thereby improving work efficiency and extending product life.

In the application scenarios of sealing valves or liquid level indicator floats, PP Hollow Balls need to maintain contact with liquids. Smooth surfaces can reduce liquid resistance and ensure smooth flow of fluids. In addition, this surface property helps to avoid liquid retention on the surface of the ball and reduce the risk of contamination, especially in scenarios with high hygiene requirements, such as the food and cosmetics industries.

For stirring beads in cosmetic bottles, the appearance not only affects the function of the product, but also directly affects the sensory experience of consumers. Smooth and flawless PP Hollow Balls provide better visual effects and enhance the overall quality of the product.

Advantages of no middle mold line
Middle mold lines are a common phenomenon in the injection molding process, but for PP Hollow Balls, this mark may affect its function. For example, in a level indicator float, mold lines can cause uneven surfaces, affecting the balance and accuracy of the float, thereby reducing the reliability of the level indication. By eliminating the mold line, the uniformity of the ball can be ensured, thereby improving product performance.

In the application of sealing valves, PP Hollow Balls need to fit tightly with the sealing seat. The middle mold line may cause tiny bulges or irregular areas on the surface of the ball, which will affect the sealing performance. The design without the middle mold line can provide a tighter contact surface, enhance the sealing effect, and reduce the possibility of leakage.

PP Hollow Balls without the middle mold line are usually manufactured with higher precision molds and production processes. This high level of manufacturing technology not only reduces the need for secondary processing, but also ensures the consistency of each product and meets the requirements of different industries for precision parts.

Combined with the necessity of specific applications
The stirring beads in the cosmetic bottle need to be in contact with the liquid for a long time and keep rolling steadily to ensure the uniform distribution of product ingredients. If the surface is rough or there are mold lines, the stirring effect will be greatly reduced and may scratch the inner wall of the bottle, affecting the user experience. Smooth and mold-line-free PP Hollow Balls provide better stirring performance and visual effects for cosmetic bottles.

In liquid level indicators, the balance and stability of the float are crucial. Mold lines may cause uneven mass distribution of the ball, affecting the precise positioning of the float in the liquid, and thus affecting the accuracy of the liquid level indication. The design with a smooth surface and no mold lines can effectively avoid these problems and improve the performance and reliability of the indicator.

Sealing valves require components to maintain good sealing performance under high pressure or high temperature environments. If there are mold lines or rough spots on the surface of the ball, the sealing surface may be damaged, causing valve leakage or even failure. Therefore, the mold-line-free design is an important condition to ensure the high performance of the sealing ball.

In order to achieve PP Hollow Balls with smooth surfaces and no intermediate mold lines, advanced injection molding technology and high-precision molds are usually used in production. For example, the flatness of the ball surface can be significantly improved by optimizing injection molding process parameters (such as pressure and temperature) and using a mold design without a parting surface.