Mold locating ring

The support plate backs up the B plate in the mold, and melt is delivered from the nozzle to the sprue bushing. The locating ring aligns the mold with the nozzle, whereas the leader pins and bushing align the two sides of the mold. In the ejection system, the sprue puller and ejector pins, are attached to the ejector plate, which is, in turn, connected to the machine s ejection plates by the ejector rod. When the mold is opened, the sprue puller draws the part to the B side of the mold, whereas the... 

The locator ring helps fit the injection mold into a press clamp. The sprue bushing is a channel by which the plastic flows from the injection... 

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.

Diaphragms or ring gates can be used for molding parts where concentricity is important such as cylindrical parts or parts where weld lines can not be tolerated. Pinpoint gates should not be used unless parts (small) are injected rapidly. Tunnel gating can also be used in such cases. Gate location should be at one of the points listed in Table 6.26. 

In addition to providing sufficient space for the mold, the press must include space for a pressure box and other elements, such as plug assist plates, cavity isolator plates, trim-in-place die plates, and ejector-ring plates. Water and vacuum lines should be properly located and should be easy to disconnect. Programmable logic controls are needed for adjustment of all rate-dependent ancillary features, such as plug assist, cavity isolator, pressure box, and trim-inplace sequence. Many newer machines are equipped with computer controls that provide for rapid setup after mold changeover. The press platens must allow easy mold removal and installation. 

Observing the Areas of Stress Concentration. The location of the molded-in stress displayed by the patterns of birefringence rings is related to the type of material used and... 

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