What are the drawbacks of water assisted injection molding?

1, Technical complexity and precision control requirements
Compared to traditional injection molding techniques, water assisted injection molding technology is more complex. It involves multiple aspects such as precise water injection, pressure control, and mold design, with higher requirements for equipment and operation. If the operation is improper or the equipment accuracy is insufficient, it may lead to unstable product quality, such as surface hysteresis marks, melt reflux, and other problems. In addition, water assisted injection molding also requires precise switching control between the melt and water, which increases the complexity of the technology.
2, Difficulty in mold design and manufacturing
Water assisted injection molding poses higher requirements for the design and manufacturing of molds. Firstly, the mold needs to be designed with a drainage system while addressing the issue of water leakage, which increases the complexity of mold design. Secondly, due to the incompressibility of water, the mold needs to withstand higher pressure, which puts higher demands on the strength and stiffness of the mold. Finally, the sealing of the mold is good to prevent high-pressure water leakage, which increases the difficulty of mold manufacturing and maintenance.
3, Product quality and performance limitations
Although water assisted injection molding can improve the quality and performance of products, it also has some limitations. Firstly, water assisted injection molding is not suitable for multi cavity injection molding methods, and the number of cavities should generally not exceed 4-6, which limits its application in large-scale production. Secondly, due to the greater heat transfer capacity of water than gas, water assisted injection molding is not suitable for high-temperature injection molding because it is prone to defects such as bubbles. In addition, water assisted injection molding may also lead to bubble hole defects in the direction of high-pressure water flow, thereby reducing the mechanical properties of the product.
4, Economic cost considerations
Although water assisted injection molding can reduce production costs, its initial investment and later maintenance costs are relatively high. Firstly, the high-pressure water injection system requires more precise pressure boosting and stabilizing devices, which increases the cost of the equipment. Secondly, the design and manufacturing costs of molds are relatively high, as they require solutions to issues such as drainage and sealing. Finally, water assisted injection molding requires regular maintenance and upkeep of the equipment to ensure its normal operation and product quality.
5, Environmental Protection and Sustainability
Although water assisted injection molding uses water as a cooling medium, which has the advantages of environmental protection and sustainability, there are also some problems in practical applications. Firstly, after completing a molding cycle, it is necessary to drain the water inside the product, which may result in wastewater treatment issues. Secondly, high-pressure water can easily corrode molds and injection nozzles, which may produce harmful substances and waste. Therefore, in the application of water assisted injection molding technology, it is necessary to pay attention to its environmental protection and sustainability issues, and take corresponding measures to reduce its impact on the environment.