How do you calculate mold cavitation output?

Divide molded parts completed by mold runtime for the raw rate, then multiply by effective cavitation efficiency. With 1,850 parts in 8 hours at 92%, that is 231.25 × 0.92 = 212.75 units/hr.

What is effective cavitation efficiency?

It is the fraction of a mold's design cavity output you actually realize per cycle, after short shots, sticking cavities and demold losses. At 92%, you are getting most but not all of the tool's potential.

Why is effective output lower than raw output?

Raw output assumes every cavity and cycle counts equally. Effective output discounts that for real cavitation losses, dropping the example from 231.25 to 212.75 units/hr.

What is a good cavitation efficiency for rubber molding?

Well-tuned multi-cavity molds often run above 90%. The example 92% is solid; values dropping into the 80s usually point to short shots, worn vents or demolding problems.

How do I improve cavitation output?

Balance the runner and gate system, clean and re-vent cavities, verify uniform cure across the platen, and reduce demold time. Each lifts effective efficiency closer to the raw rate.

Raw rate vs. effective rate, which do I plan with?

Plan with the effective rate. The raw 231.25 units/hr is the ceiling; the effective 212.75 units/hr is what the tool sustains, so it is the safer basis for scheduling and standards.

Gaskets, Seals, O-Rings & Elastomer Components calculator

Mold Cavitation Output Calculator

Mold cavitation output measures the effective hourly rate of finished parts from a molding tool once cavitation efficiency is taken into account. Effective cavitation efficiency captures the reality that not every cavity fills and demolds perfectly every cycle, so the raw parts-per-hour rate overstates sustainable throughput. Molding supervisors and industrial engineers in gasket and O-ring production use this rate to compare tools, set realistic standards and spot when a multi-cavity mold is underperforming its design. A gap between raw and effective output points to short shots, sticking cavities or demolding delays dragging the tool below nameplate.

What this calculator does

Estimate effective molded seal output per hour from completed parts, runtime, and realistic cavitation efficiency.
Use it when a mold has blocked cavities, short shots, knit-line rejects, flash problems, venting issues, or cavity imbalance and the team needs a defensible output rate.
It computes the raw molded output rate from parts completed over runtime, then scales it by effective cavitation efficiency to give a sustainable hourly rate.

Formula used

Raw mold cavitation output = molded parts completed ÷ mold runtime
Effective mold cavitation output = raw output × effective cavitation efficiency

Inputs explained

Molded parts completed:
Mold runtime:
Effective cavitation efficiency:

How to use the result

Use it to set or audit a molding rate standard, or to compare two tools on a common units-per-hour basis.
It averages over the runtime, so a single mid-shift stoppage or a slow startup ramp can distort the rate unless you segment the data.

Current U.S. benchmarks

The U.S. has 11,391 plastics and rubber products establishments employing about 815,988 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate mold cavitation output? Divide molded parts completed by mold runtime for the raw rate, then multiply by effective cavitation efficiency. With 1,850 parts in 8 hours at 92%, that is 231.25 × 0.92 = 212.75 units/hr.
What is effective cavitation efficiency? It is the fraction of a mold's design cavity output you actually realize per cycle, after short shots, sticking cavities and demold losses. At 92%, you are getting most but not all of the tool's potential.
Why is effective output lower than raw output? Raw output assumes every cavity and cycle counts equally. Effective output discounts that for real cavitation losses, dropping the example from 231.25 to 212.75 units/hr.
What is a good cavitation efficiency for rubber molding? Well-tuned multi-cavity molds often run above 90%. The example 92% is solid; values dropping into the 80s usually point to short shots, worn vents or demolding problems.
How do I improve cavitation output? Balance the runner and gate system, clean and re-vent cavities, verify uniform cure across the platen, and reduce demold time. Each lifts effective efficiency closer to the raw rate.

Last reviewed 2026-05-12.