Sequence dependent changeover

With the main purpose of developing more efficient optimization models for batch sequential processes, especially those involving sequence-dependent changeovers, different approaches were proposed based on the concept of batch precedence. 

Demand patterns can also vary significantly ranging from cases where due dates must be obeyed to cases where production targets must be met over a time horizon (fixed or minimum). Changeovers are also a very important factor, which is particularly critical in cases of transitions that are sequence dependent on the products, as opposed to simple setups that are only unit dependent. 

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. 

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