What should I do if the sprue sticks to the film during injection molding processing?

Injection molding processing is an important technology in modern manufacturing industry, which is widely used in automotive, home appliance, medical, consumer electronics and other industries. In the process of injection molding, the design and treatment of sprue system plays a vital role in the quality of products. Among them, sprue sticking film is a common problem, which not only affects the appearance quality of the product, but also may lead to the reduction of production efficiency. In this article, we will discuss in detail how to deal with the problem of sprue sticking film in injection molding process.

What are the causes of sprue film?

Common causes include improper mold temperature control, incorrect injection parameter settings, irrational sprue design, and the characteristics of the plastic material. For example, if the mold temperature is too low, the molten plastic may cool quickly on contact with the mold surface, increasing the likelihood of adhesion. Similarly, if the injection rate is too fast or the pressure is too high, it may result in localized overheating of the plastic at the sprue due to shear heat, followed by rapid cooling sticking to the mold.

The problem of adhering film to the sprue can be addressed in several ways:

1. Optimize the temperature control system of the mold. Ensure that the mold temperature is uniform to avoid localized overheating or overcooling. By improving the cooling water circuit design of the mold, the heat transfer efficiency can be effectively improved.

2. Adjust the injection parameters. Reasonably set the injection speed, pressure, time and other parameters to adapt to the fluidity and molding requirements of different plastic materials. This usually needs to be done through several trial molds and adjustments.

3. Improve the sprue design. Adoption of sprue shapes and sizes suitable for specific plastic materials, such as the use of larger gates and reasonable cooling systems, can reduce the possibility of sticky film.

4. Selection of suitable plastic materials. Different plastic materials have different viscosity and thermal properties. Choosing the right material for the molding process can help reduce the problem of sticky film.

5. Use a mold release agent. Spraying or applying the right amount of release agent on the surface of the mold can reduce the adhesion between the plastic and the mold, thus reducing the occurrence of sticky film.

6. Inspect and maintain the mold regularly. Keeping the molds clean and intact and replacing worn parts in time can avoid sticky film problems caused by damaged molds.