How do you calculate injection moulding cycle time?

Add the fill time, the pack and hold time, the longer of the cooling timer and screw recovery, and the mould open, eject and close time. 1.5 + 4 + 10 + 5 is 20.5 s, 175.6 shots an hour, 1.5 s inside a 22 s quote, the Injection Molding Cycle Time calculator's own example.

Why the longer of cooling and screw recovery?

The screw recovers for the next shot while the part cools, and the mould cannot open until both are finished. If recovery takes longer than the cooling timer, the screw, not cooling, sets the cycle; the Recovery wait column shows by how much.

What does a recovery wait mean?

The mould is waiting for the screw. Cutting cooling time will not help; a higher screw speed, more back pressure headroom, a larger barrel or a press with more plasticising capacity will. In the example the clip mould waits 3.5 s every shot.

How is the press cost per part worked out?

The press hour rate times the cycle in hours, divided by the cavities. At 48 an hour, a 16.3 s cycle on 32 cavities is 0.0068 a part against 0.0058 at the 14 s quote.

Does shots per hour include downtime?

No. It is the machine rate at the cycle. Downtime, start-up scrap and changeovers reduce what a shift actually makes; use an OEE tracker for those.

Does the workbook use macros?

No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test moulds and shows Self-check: PASS.

Production and Throughput

Injection Molding Cycle Time Excel Template

Injection moulding cycle = fill + pack and hold + the longer of cooling timer and screw recovery + mould open, eject and close. Give every mould a row and see its cycle against the cycle it was quoted at, its parts per hour and press cost per part, and the moulds where the screw, not cooling, sets the cycle.

Free, and a plain .xlsx with no macros to enable. A CSV with live formulas and a printed how-to guide come with it.

Overview

This injection moulding cycle time template is a working Excel workbook for moulding process engineers, production managers and estimators. Each mould is one row with its press, cavities and the phase times from the setup sheet and press monitor: fill, pack and hold, the cooling timer, screw recovery, and mould open, eject and close, with the cycle its quote was built on. Screw recovery runs during the cooling timer, so the longer of the two sets that phase. The workbook gives each mould's cycle, shots and parts per hour, headroom to the quote and the press cost per part at the cycle and at the quote. It ships with ten moulds on three press sizes at a fictional moulder, so every tile and chart is filled in when you open it.

In the example a 4-cavity gear housing fills in 1.5 s, holds for 4, cools for 10 while the screw recovers in 7, and opens and closes in 5: a 20.5 s cycle, 1.5 s inside its 22 s quote, 176 shots and 702 parts an hour. A 32-cavity clip mould has a large shot on a small screw: recovery takes 8.5 s against a 5 s cooling timer, so the mould waits 3.5 s every shot for the screw and runs at 16.3 s against a 14 s quote. A lens bezel whose hold was extended after a sink mark runs 2.8% over its quote.

Shots per hour is the machine rate, without downtime, start-up scrap or changeovers. The download is a plain .xlsx with no macros. A CSV with live formulas is also included for other tools; the dashboard, charts, dropdowns and self-check are in the .xlsx.

What this template includes

Setup sheet with your plant, currency and near band, and the presses with their hourly rate
Moulds table, one row per mould: part, press, cavities, fill, pack and hold, cooling timer, screw recovery, open-eject-close and quoted cycle, with a Check column
Per mould: cooling phase, cycle, shots and parts per hour, headroom to the quoted cycle, screw recovery wait, cooling in the cycle, press cost per part at the cycle and at the quote, and a status in words
Dashboard with four tiles (moulds, slower than quoted, screw recovery sets the cycle, worst headroom), each cycle split by phase, cycle against quoted cycle, and the mould table
Method sheet with every formula, and a Verify sheet that re-checks the formulas against an independent reference and the Injection Molding Cycle Time calculator (Self-check: PASS)
CSV with live formulas for the Moulds table; the dashboard, charts, dropdowns and self-check are in the .xlsx

Suggested use case

Use it to check running moulds against the cycles they were quoted at, to find the phase to attack on a slow mould, or to spot moulds where a bigger screw or faster recovery, not more cooling, would shorten the cycle.

How to use it

On Setup, type your plant, currency and near band, and list your presses with their hourly rate.
On Moulds, give each mould a row: press, cavities, fill, pack and hold, cooling timer, screw recovery, open-eject-close and the quoted cycle.
Fix anything the Check column names.
Open the Dashboard: each cycle by phase, cycle against quote, and the moulds the screw holds up.

Frequently Asked Questions

How do you calculate injection moulding cycle time?: Add the fill time, the pack and hold time, the longer of the cooling timer and screw recovery, and the mould open, eject and close time. 1.5 + 4 + 10 + 5 is 20.5 s, 175.6 shots an hour, 1.5 s inside a 22 s quote, the Injection Molding Cycle Time calculator's own example.
Why the longer of cooling and screw recovery?: The screw recovers for the next shot while the part cools, and the mould cannot open until both are finished. If recovery takes longer than the cooling timer, the screw, not cooling, sets the cycle; the Recovery wait column shows by how much.
What does a recovery wait mean?: The mould is waiting for the screw. Cutting cooling time will not help; a higher screw speed, more back pressure headroom, a larger barrel or a press with more plasticising capacity will. In the example the clip mould waits 3.5 s every shot.
How is the press cost per part worked out?: The press hour rate times the cycle in hours, divided by the cavities. At 48 an hour, a 16.3 s cycle on 32 cavities is 0.0068 a part against 0.0058 at the 14 s quote.
Does shots per hour include downtime?: No. It is the machine rate at the cycle. Downtime, start-up scrap and changeovers reduce what a shift actually makes; use an OEE tracker for those.
Does the workbook use macros?: No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test moulds and shows Self-check: PASS.