Phases of an Injection Molding Cycle

Lessons 2 through 6 introduced the components of an injection molding machine with which the material is formed from the pelletized raw material into the finished injection-molded part. 

To manufacture an injection-molded part, the machine s structural units must work together in a practical manner. This cooperation between the units results in the injection molding process during which the molded part is formed. 

The injection molding process consists of individual phases or stages which follow one another, overlapping to some extent, and are continuously repeated. We refer to a process of this type as a cycle and therefore speak of a repeating injection molding cycle. Nowadays, it is customary for the injection molding cycle to proceed automatically from phase to phase. 

In most cases the cycle also repeats itself automatically. Only imder certain conditions or for special molded parts may it be necessary for the machine to stop at the end of a cycle. After manual intervention by the machine operator, the machine is prepared for the next eycle and then restarted. This is done with molded elastomer parts, for example, whieh generally must be removed by hand. 

The CD is produced by a fully automatic method, for example. In this ease the maehine operator intervenes only when problems arise. 

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Figure 7-1 shows the various phases of an injection molding cycle and their sequence. 

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