An injection plastic mold is a tool made up of a series of parts that shape and cool molten plastic to create discrete part shapes. The injection mold is divided into many parts, the common parts are:

(1) splint

  The mold halves are connected to the forming platen by means of clamping plates. Die clamps use large bolts to hold them in place; other machines use magnets to hold the die to the platen.

(2) Nozzle/gate bushing

  Liquid plastic is pushed through the nozzle of the forming barrel. The nozzle rests on surfaces on the mold called gate bushings and locating rings, which help center the nozzle on the mold. Feed system

  Plastic flows through sprue bushings in the sprue, and then to the individual runners that bring material to the gate - the entry point for material into each cavity.

Gates and runners can be reground (shredded) and reused. They can be eliminated by using a hot runner system.

(3) Tooth decay

  The cavity is the area in the mold where the part takes the desired shape. The mold has to be balanced, so usually, only a certain amount of cavitation is allowed (1, 2, 4, 8, etc...)

(4) Cooling system

  The plastic is heat injected and cooled through cooling channels that allow conduction to cool the part. The working fluid is usually water, but oil can be used for high-temperature applications. Guidepost/bushing

  Ensure that the cavity and core halves are properly aligned during clamping by using guide pins (or struts) and guide bushes (or sleeves). injection system

  Use a series of pins or rods to push the parts away from the core. These series are called ejector systems.

(5) Ejector system

   Including ejector sleeve, thimble, and so on. A thimble, such as a straight ejector pin, is installed in the top plate. The forward movement of the ejector plate allows the pins to move forward, pushing the part off the core. The ejector retainer plate holds the pins in the ejector plate.