Abstract: Moulds for injection molding of plastic parts comprising a die and a punch which define, in the closed mould condition, a cavity intended to receive plastic material injected by a press are provided. The punch may comprise a central element and a pair of first lateral elements arranged on longitudinally opposite sides relative to the central element, each of the first lateral elements being slidably guided along a respective inclined lateral surface of the central element to be displaced between a moulding position and an ejection position.