The body of the pin (M-K) here has a center core of 40 Rc and an extremely hard nitride surface of 65-74 Rc. The heads are hot forged to obtain greater tensile strength and are annealed to 30-35 Rc for toughness. Shoulder style pins as well as special order pins are also available.
Case Hardened Ejector Pins – Application
Case hardened ejector pins make up the majority of ejector pins in use today. The extremely hard surface of the pins make them an excellent choice for normal applications requiring average strength, rigidity, and good wear properties. As long as the hardened case is not removed, these pins will give long, dependable life.
Case Hardened Ejector Pins – Actuation
After the mold closes, the part cavity is filled by the sprue and runner system. When the part is cooled the mold opens and the sprue puller pin separates the sprue from the injection nozzle. The ejector plate then makes contact with the machine ejector rod that forces the ejector pins forward, ejecting the part and its runner system. When the mold closes return pins force the ejector system back.
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