How do you calculate compression moulding cycle time?

Add the minutes to load the charge, close and breathe, cure, and open and demould. The cavities divided by that cycle give parts per minute. 12 cavities on a 1 minute cycle is 12 a minute, so 120 parts take 10 minutes, 0.183 hours with a 10% allowance, the Compression Molding Cycle Time calculator's own example.

How many press hours does an order need?

Order quantity divided by parts per minute, divided by 60, times (1 + allowance). 2,400 bushings at 8 cavities and 17.5 minutes is 87.5 hours, 98 hours with a 12% allowance.

What should the allowance cover?

Everything the cycle does not: mould changes and heat-up, first-off inspection, deflashing at the press, cleaning and delays, as a share of the moulding time. Use your own figure from past jobs; the example uses 10% to 15%.

What is the cure share?

Cure minutes divided by cycle minutes. A high share means the cycle is set by the compound and section; a low one means loading and demoulding, which are often easier to speed up, take most of the time.

How is press capacity judged?

Each press's jobs' required hours are added and divided by its available hours. Above 100% is Over capacity, from the threshold on Setup (85% in the example) Near capacity, and below that Under capacity.

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 jobs and shows Self-check: PASS.

Production and Throughput

Compression Molding Cycle Time Excel Template

Press hours = order quantity ÷ (cavities ÷ cycle minutes) ÷ 60 × (1 + allowance), with the cycle = load + close and breathe + cure + open and demould. Give every moulding job a row and see its parts per hour, the press hours it needs, and whether each press's jobs fit the hours it has.

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 compression moulding cycle time template is a working Excel workbook for process engineers, production planners and estimators at rubber, elastomer, composite and thermoset moulders. Each job is one row with its press, order quantity, cavities and the minutes of each part of the press cycle: loading the charge, closing and breathing, cure, and opening and demoulding. The workbook gives the parts per hour and the press hours the order needs, with an allowance for mould changes, heat-up and first-off checks, and adds the jobs up by press against the hours each has in the period. It ships with a week of twelve jobs on six presses at a fictional rubber moulder, so every tile and chart is filled in when you open it.

In the example a natural rubber suspension bushing cures for 12 of its 17.5 minute cycle in an 8 cavity mould: 27 parts an hour, so 2,400 bushings need 87.5 press hours, 98 with a 12% allowance, on a press that has 80 this week. With a washer order as well, that press is loaded to 143%, the only one over capacity. Three more presses are above the 85% near-capacity threshold, and the three-shift press P1 has 33 hours spare.

Cure times should come from your validated cure curve for the compound and section. The download is a plain .xlsx with no macros. A CSV with live formulas is also included for other tools; the press capacity, dashboard, charts, dropdowns and self-check are in the .xlsx.

What this template includes

Setup sheet with your plant and planning period, the near-capacity threshold, and the presses with the hours each has in the period
Jobs table, one row per moulding job: part, compound, press, order quantity, cavities, load, close and breathe, cure and open and demould minutes, and an allowance, with a Check column
Per job: cycle, parts per minute and per hour, cure share of the cycle, and base and required press hours
Per press: available and required hours, load, spare hours, jobs, parts and a capacity status in words
Dashboard with four tiles (jobs, press hours required, presses over capacity, busiest press load), each job's cycle split into its segments, required against available hours by press, and the press and job tables
Method sheet with every formula, and a Verify sheet that re-checks the formulas against an independent reference and the Compression Molding Cycle Time calculator (Self-check: PASS)
CSV with live formulas for the Jobs table; the press capacity, dashboard, charts, dropdowns and self-check are in the .xlsx

Suggested use case

Use it to plan a week of compression moulding across your presses, to quote press time for a new part, or to see whether more cavities or a shorter cure would get an overloaded press back under its hours.

How to use it

On Setup, type the plant and planning period, and list your presses with the hours each has in the period.
On Jobs, give each job a row: press, order quantity, cavities, the load, close and breathe, cure and open and demould minutes, and an allowance.
Fix anything the Check column names.
Open the Dashboard: required against available hours by press, and where each cycle's minutes go.

Frequently Asked Questions

How do you calculate compression moulding cycle time?: Add the minutes to load the charge, close and breathe, cure, and open and demould. The cavities divided by that cycle give parts per minute. 12 cavities on a 1 minute cycle is 12 a minute, so 120 parts take 10 minutes, 0.183 hours with a 10% allowance, the Compression Molding Cycle Time calculator's own example.
How many press hours does an order need?: Order quantity divided by parts per minute, divided by 60, times (1 + allowance). 2,400 bushings at 8 cavities and 17.5 minutes is 87.5 hours, 98 hours with a 12% allowance.
What should the allowance cover?: Everything the cycle does not: mould changes and heat-up, first-off inspection, deflashing at the press, cleaning and delays, as a share of the moulding time. Use your own figure from past jobs; the example uses 10% to 15%.
What is the cure share?: Cure minutes divided by cycle minutes. A high share means the cycle is set by the compound and section; a low one means loading and demoulding, which are often easier to speed up, take most of the time.
How is press capacity judged?: Each press's jobs' required hours are added and divided by its available hours. Above 100% is Over capacity, from the threshold on Setup (85% in the example) Near capacity, and below that Under capacity.
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 jobs and shows Self-check: PASS.