Clamping hydromechanical

IMM with an oil hydrauUc system provides the power to turn the screw to plasticate the plastic, inject the melt into the mold cavity, close the mold clamp, hold clamp tonnage, release the clamp, and eject the molded part. A number of hydraulic components are required to provide this power, including motors, pumps, directional valves, fittings, tubings, and oil reservoirs/tanks. See drive-system control hydraulic fluid influenced by heat, injection molding machine hydromechanical clamp See clamping, hydromechanical. 

In hydromechanical clamping units, toggles are combined with hydraulic cylinders. The toggle is used to open and close the clamp, but the hydraulic piston builds the clamp pressure. Since this requires small hydraulic cylinders, clamp movement is faster and the clamping units are smaller than comparable hydraulic units. However, hydraulic clamping provides better control of the clamp force. 

Clamping units support the mold, hold the mold closed during injection, open and close the mold as rapidly as possible, provide for part ejection, and provide mold close protection. The four types of clamps are hydraulic, hydraulically actuated toggle (mechanical), electrically actuated toggle, and hydromechanical. 

There are a number of variations in machine constmction and processing techniques (10). There are hydraulic (Fig. 4), hydromechanical, and toggle clamping machines (Fig. 4). There are also tiebar-less clamps as shown in Figure 5, and two-platen machines that were developed to save floor space over the normal three-platen machine. 

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