Advantages and Disadvantages of Injection Molding Processing Low Speed Mold Filling

Injection molding is a common molding method in the modern plastics industry, which is achieved by injecting molten plastic into the mold, cooling and curing to obtain the desired shape of the product. In the injection molding process, mold filling speed is a key parameter, which is directly related to product quality, production efficiency and cost control.

Mold filling speed refers to the speed at which the plastic melt enters the mold cavity from the injector nozzle. Low-speed mold filling is to complete the process at a lower speed.

The advantages of this type of mold filling are as follows:

1. Low-speed mold filling helps to reduce the generation of injection phenomenon. When the melt is injected into the mold at high speed, due to the fast flow rate and high pressure, it is easy to produce spray at the far end of the mold, resulting in a short shot or melt fracture, affecting the product appearance and dimensional accuracy. Low-speed mold filling can alleviate this problem to a certain extent. 2.

2. Next, low-speed mold filling facilitates the smooth advancement of the melt front. In the process of mold filling, if the melt front is not stable, it will lead to air bubbles, which will form defects inside the product. Adopting low-speed mold filling can effectively avoid or reduce this situation.

3. Low-speed mold filling helps to improve the flow behavior of the melt. At lower speeds, the plastic melt has more time for heat exchange, which helps to improve the consistency of molecular chain arrangement and crystallinity, thus enhancing the mechanical properties of the final product.

Low speed mold filling also has some disadvantages that should not be overlooked.

1. It prolongs the entire injection cycle. Because of the slow melt filling speed, accordingly, the whole production cycle will be lengthened, which may mean lower productivity and increased production costs for mass production. 2.

2. Another disadvantage is that it may lead to material degradation. Due to the slow speed of mold filling, the residence time of the melt in the barrel grows, and if the temperature is not properly controlled, the prolonged high-temperature effect may lead to thermal degradation of the plastic material, affecting the product performance and color stability.

3. Low-speed mold filling may also cause internal stress problems. In the process of slow filling of the melt, due to the different cooling rates of different parts, may produce uneven cooling contraction in the product, triggering the generation of internal stresses, which is detrimental to the stability and service life of the product.