What is an ejector plate used for? What are the properties of the ejector plate?
The purpose of this member is to transmit the ejector force from the actuating system of the injection machine to the molding via an ejector element.
The force required to eject a molding is appreciable, particular with those moldings which are deep and which incorporate little draft. Most ejector plates that fail in operation do so in fact because too thin a plate is specified in the design. The ejector plate must be sufficiently thick not to deflect to any significant extent. Deflection tends to occur at the beginning of the ejector stroke when there is maximum adhesion between the molding and the core. The deflection of any beam is inversely proportional to the cube of its depth and, therefore, a relatively small increase in plate thickness will decrease the deflection of the plate.