Meaning
Energy intensity represents the amount of electrical power drawn per unit of mass during the manufacturing of a polymer product. Operators track specific energy consumption to quantify the total work performed by an injection moulding machine or extruder relative to the throughput of resin. This metric accounts for the operation of heaters, motors, and peripheral cooling units.
It functions as a boundary for production efficiency that stops at the physical delivery of a finished component.
Moulding Efficiency
Processing variables such as barrel temperature, screw rotation speed, and injection pressure dictate the draw on the electrical grid. Higher screw speeds typically demand more power, yet they might shorten cycle times to lower the energy demand per piece. Moulders maintain a balance between these settings to minimize waste while keeping the plastic melt within the required thermal window.
Variations in resin viscosity require different torque levels, forcing adjustments that shift the load profile on the main drive motor.
Material Economics
Virgin resin grades display consistent melt flow rates that allow for predictable power usage during plastification. Adding regrind or fillers alters the thermal conductivity and internal friction of the material, which forces the heater bands to compensate with different duty cycles. A datasheet value describes the theoretical energy requirement under controlled laboratory conditions, whereas the value a moulder observes on the factory floor includes the overhead of auxiliary cooling and compressed air systems.
Discrepancies between these figures reveal the degree of mechanical drag or thermal loss inside the production line.
Production Variance
Tooling geometry directly influences the cooling time, which remains a primary driver of power draw per kilogram of plastic. Thick walls require longer residence times that keep the auxiliary units running after the mould opens, driving up the total kilowatt hours required to eject a single part. Shortening the cooling phase reduces this demand, provided the part dimensions remain within tolerance.
This indicator quantifies the energy cost of cycle stability.
