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Injection Molding Startup Peak Demand Calculator

Screen simultaneous injection molding equipment starts against a facility demand target and a simple staged-start alternative.

Formula and method

Concurrent peak = base facility load + startup load 1 + startup load 2 + startup load 3. Staged screen = base load + largest single startup load.

Inputs and units

Obtain interval demand data or logged startup kW for the press, dryers, temperature-control units, chillers, compressors, and other loads that may overlap. Enter the facility load immediately before startup and the relevant demand target.

Worked example

A 120 kW base plus 80, 70, and 30 kW startup loads screens at 300 kW concurrent. Against a 250 kW target, the margin is −50 kW; one-at-a-time staging screens at 200 kW.

When to use it

Use before shift startup or a multi-machine restart to identify load combinations that deserve timed measurement and an approved startup sequence.

How to interpret the result

A positive staged margin only shows arithmetic headroom. Actual utility billing uses a defined interval and may capture motor inrush, cycling heaters, compressors, chillers, and overlapping loads differently.

Assumptions and limitations

This is not an electrical protection, conductor, breaker, transformer, generator, or arc-flash sizing tool. Qualified electrical review and utility tariff data govern those decisions.

Validation guidance

Compare the screen with the facility meter at the billing interval. Confirm that staging does not create thermal, material, quality, staffing, or production conflicts.

FAQ

Can this result replace a measured production trial?

No. Preserve the meter, time window, product quality, machine, mold, material, process, and boundary with the result.

Sources

Plastics Engineering energy-management guidance