Structure and Function of a Molding Machine's Injection System
The injection system of a molding machine refers to the channel through which molten plastic flows from the nozzle of the injection machine into the mold cavity. It consists of a main runner, sub-runners, a gate, and a cold slug.
The main runner connects the injection machine nozzle to the sub-runners. It is in the first section of the channel that the molten plastic enters the mold cavity. Typically, it has a conical shape. The design of the main runner needs to consider factors such as the fluidity of the plastic, pressure loss, and heat loss to ensure the smooth flow of molten plastic into the mold cavity.
Sub-runners connect the main runner to the gates. Their function is to distribute the molten plastic evenly to each gate, ensuring that the molten plastic can simultaneously fill the mold cavity. The design of sub-runners needs to consider factors such as the fluidity of the plastic, pressure loss, and heat loss, as well as factors such as the length, diameter, and shape of the sub-runners, to ensure that the molten plastic can flow smoothly and fill the mold cavity.
The gate connects the sub-runner to the mold cavity. Its function is to control the speed and flow rate of the molten plastic entering the mold cavity, ensuring that the molten plastic can fill the mold cavity and form the desired plastic product. The design of the gate needs to consider factors such as the fluidity of the plastic, pressure loss, and heat loss, as well as the location, shape, and size of the gate, to ensure that the molten plastic can smoothly enter the mold cavity and form the desired plastic product.
The cold slug well is a cavity located at the end of the main runner. Its function is to store the cold slug generated during the injection process, preventing the cold slug from entering the mold cavity and affecting the quality of the plastic product. The design of the cold slug well needs to consider factors such as the fluidity of the plastic, pressure loss, and heat loss, as well as the location, shape, and size of the cold slug well, to ensure that the cold slug can be smoothly stored and discharged from the mold cavity.
