Meaning
Duration required to complete one full sequence of the injection moulding process from mould closure to the subsequent mould closure. Total cycle time includes the periods for injection, holding, cooling, and part ejection. This duration determines the throughput of a production cell.
Cooling Phase
Thermal dissipation accounts for the largest portion of the sequence in most applications. The resin must reach a temperature below its heat deflection point before the tool opens. A long cycle time is often the result of thick walls because polymers act as thermal insulators.
Efficient water channels within the tool help to shorten this interval.
Mechanical Sequence
Clamping and ejection movements contribute a fixed amount of time to the total. Faster clamp speeds reduce the dead time between shots. Modern machines use synchronous movements to overlap the recovery of the screw with the cooling of the part.
This optimization of the cycle time prevents unnecessary idle periods for the hydraulic or electric motors.
Economic Output
Profitability scales with the number of parts produced per hour. A reduction of one second provides a measurable increase in annual capacity. Moulders balance the cycle time against part quality to avoid warping or sink marks.
