A "顶针" (Ejector), also known as a push pin, core pin, center pin, or support pin, is a plastic mold component used in plastic molding processes. The term "顶针" is sometimes used for lathe centers as well, but its meaning varies depending on the context.
The uses of "顶针" are as follows:
In plastic molds, it is primarily used to separate the molded product from the mold, which is its most common application.
Hard alloy "顶针" such as tungsten steel pins can be used to eject long and narrow holes or components.
"顶针" in the context of lathes or grinding machines refers to a conical metal rod that supports a workpiece and allows it to rotate around it. This type of "顶针" is entirely different from the "顶针" used in plastic mold components.
In plastic molds, "顶针" can also be used for stabilization and is referred to as "镶针" (insert pin).
There are various types of "顶针" for plastic molds, including round ejector pins, support pins, standard ejector pins, and non-standard ejector pins.
The materials used for plastic mold ejector pins include SKH51, SKD61, SKD11, and 65Mn.
SKH51 ejector pins have better toughness compared to SKD61. SKD61 ejector pins can withstand high temperatures up to 1600°C, and their wear resistance can be significantly improved through nitriding treatment on the surface. 65Mn ejector pins are of lower quality and are prone to being brittle and breaking, so most plastic molds no longer use 65Mn material for ejector pins.
