In the manufacturing process of medical injection molds, the shape and size of the gate have a crucial impact on the quality of the plastic parts. To enhance the quality and production efficiency of the plastic parts, we usually opt for small gates when designing medical injection molds. So, what are the significant advantages of using small gates in medical injection molds?

Firstly, small gates can effectively increase the flow rate of the material as it passes through. Due to the large pressure difference across the small gate, this design can reduce the apparent viscosity of the melt, making the mold filling process smoother. This characteristic is of positive significance for improving injection molding efficiency.

Secondly, small gates help to increase the temperature of the melt, thereby enhancing its fluidity. At the small gate, due to the greater frictional resistance, some of the energy of the melt is converted into frictional heat as it passes through, causing a temperature rise. This is particularly beneficial for producing thin-walled plastic parts or those with fine patterns, as the higher temperature helps the melt to better fill the mold, improving the quality of the plastic parts.

Furthermore, small gates can control and shorten the time for material replenishment, reduce the internal stress of the plastic parts, and thus shorten the molding cycle. During the injection process, the packing phase needs to continue until the gate solidifies. Since small gates solidify quickly and the replenishment time is short, the orientation and strain of the macromolecules during solidification are reduced, greatly lowering the internal stress of the replenished material. At the same time, the adaptive sealing of the small gate can also more accurately control the replenishment time, further improving the quality of the plastic parts.

In addition, small gates can balance the feeding speed of each cavity. Due to the greater resistance at the small gate, each cavity can only be filled at a similar time when the flow channel is full and has sufficient pressure. This design helps to improve the imbalance in the feeding speed of each cavity, ensuring the consistency and uniformity of the plastic parts.

Lastly, small gates are also convenient for trimming the plastic parts. Due to the small size of the small gate, it can be quickly removed manually, and the resulting mark is small, reducing the time required for grinding. However, it should be noted that an excessively small gate will greatly increase the flow resistance and prolong the mold filling time. Therefore, for melts with high viscosity and those where the shear rate has little effect on the apparent viscosity, it is not advisable to use an excessively small gate design.

In summary, the use of small gates in medical injection molds has many advantages, including improving injection molding efficiency, enhancing the quality of plastic parts, shortening the molding cycle, and facilitating trimming. However, in practical applications, it is also necessary to reasonably choose the gate size to ensure the best production results.