Mold-cavity retainer plate

Cavity-retainer plate n. A plate in a mold that holds the cavities and forces. Such plates are at the mold parting line and usually contain the guide pins and bushings. 

Nest plate A retainer plate with depressed area for cavity blocks used in injection molding. 

Retainer plate n. In injection molding, a plate that reinforces the cavity block against the injection pressure, and also serves as an anchor for the cavities, ejector pins, guide pins, and bushings. The retainer plate is usually cored for circulating water or steam. 

Sprue Lock n In injection molding, a portion of the plastic composition that is held in the cold-slug well by an undercut, used to pull the sprue out of the sprue passage as the mold is opened. The sprue lock itself is pushed out of the mold by an ejector pin. When the undercut occurs on the cavity-block retainer plate, this pin is called the sprue-ejector pin. 

Figure 7.10 Schematic of a two-plate mold. A Knockout plate, B ejector retainer plate, C ejector travel, D support plate, E sleeve-type ejector, F rear cavity plate, G cavity, H front cavity plate, I locating ring, J sprue bushing, K damping piate, L parting iine, M core or force, N ejector pin, O sprue puiier, P damping piate, Q retainer piate, R knockout pins, S core or force pin.

---