The processing accuracy and cost of the micro-injection molding mold determine the cost of the product and the possibility of mass production, so the design of a mold with a reasonable structure is the key to obtain high-quality injection products. The key technologies of micro-injection molding mold design mainly include variable temperature mold design, vacuum exhaust system design, mold release mechanism design and so on.

Variable temperature mold design. In the process of micro-injection molding, due to the large surface area of the mold cavity compared to the volume, resulting in a large range of changes in the melt temperature in the filling stage, seriously affecting the molding quality of the products and molding cycle, therefore, the micro-injection mold usually need to design the mold temperature system. At present, the mold temperature system mainly has induction heating variable mold temperature system, electric hot water cooling variable mold temperature system. For example, the U.S. Georgia Institute of Technology YAO and other design of high-frequency induction heating variable mold temperature system, can be in 5s to make the cavity temperature from room temperature to 240 ℃, greatly reducing the molding cycle. In the process of rapid cold and hot injection molding, must need to consider the mold steel resistance.

Vacuum exhaust system design. Due to the high precision of micro-mold surface processing, when the mold is closed, the gap between the moving mold and the fixed mold is very small, the cavity of the residual air and melt release gas is difficult to discharge from the cavity gap, affecting the quality of the product molding and melt filling rate, micro-molds are usually designed with a vacuum exhaust system. At present, the vacuum exhaust method is mainly through the cavity around the seal, in the parting surface to open the exhaust channel, and then use a vacuum pump to pump the gas from the cavity.

In view of the micro-products with light weight, thin wall, low strength characteristics, the traditional mold release mechanism is easy to make the micro-structure deformation, or even damage, seriously affecting the molding quality of the products. In order to make the products smoothly demolded and to ensure their molding quality, micro-injection molds need to be designed with a demolding method suitable for the structural characteristics of the micro-products. For the characteristics of different micro-product structures, different mold release design mechanisms are used. The indirect mold release mechanism for large micro-products does not directly act on the product, but directly pushes out the relatively large-sized runner, and then drives the product out of the mold through the runner and gate, thus ensuring the dimensional accuracy and surface quality of the product.