How do you calculate delivery capacity in rotational molding?

Multiply parts per cycle by available cycles for gross capacity, then apply uptime and yield. With 4 parts × 480 cycles = 1920 gross, at 90% uptime and 97% yield, good capacity is about 1676 units.

What is the difference between gross and good capacity?

Gross capacity (1920 here) assumes zero downtime and perfect parts. Good capacity (1676) subtracts 192 units of uptime loss and about 52 units of yield loss to give what you can actually deliver.

Why do uptime and yield both reduce capacity?

They hit at different stages — uptime removes whole cycles you never run, and yield removes defective parts within the cycles you do run. Both must be applied, dropping 1920 gross to roughly 1676 good.

What is a realistic first-pass yield for rotomolding?

Mature parts often run 95% to 98% first-pass yield; the 97% here is typical for a stable process. New molds or thin-wall parts can sit lower until the cycle is dialed in.

How do I use this for a delivery commitment?

Promise against good capacity, not gross. Committing 1900 units when the line delivers 1676 sets you up to miss; quoting near 1676 leaves you able to keep the date.

How much does uptime affect deliverable parts?

A lot — the 10% downtime here costs 192 parts before yield even applies. Recovering 5 points of uptime would add roughly 90 deliverable units over the period.

Rotational Molding calculator

Delivery Capacity Calculator

Delivery Capacity tells you how many good, shippable parts a rotomolding line can commit to over a planning period after uptime and yield losses. Schedulers and account managers use it to make delivery promises they can actually keep, rather than quoting the machine's gross rating. Because a rotomolding carousel loses parts to both downtime and cure defects, gross capacity always overstates what leaves the door. This calculator layers uptime and first-pass yield onto the raw cycle count so the number you promise a customer is the number you can ship.

What this calculator does

Delivery Capacity tells you how many good, shippable parts a rotomolding line can commit to over a planning period after uptime and yield losses.
Use it when delivery capacity in rotational molding is being asked to take on more work and you need to know if there is room.
It computes deliverable good-part capacity as parts per cycle times available cycles, scaled by uptime and first-pass yield.

Formula used

Gross delivery capacity capacity = units per cycle × available cycles
Good capacity = gross capacity × uptime × yield

Inputs explained

Good parts per oven cycle:
Available oven cycles in the period:
Machine uptime:
First-pass yield:

How to use the result

Use it when committing delivery volumes over a shift, week, or month for a rotomolded product.
It uses period-average uptime and yield, so it will not capture a bad week where a mold problem tanks yield below the average you entered.

Current U.S. benchmarks

The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 9,635 plastics product manufacturing establishments employing about 677,302 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate delivery capacity in rotational molding? Multiply parts per cycle by available cycles for gross capacity, then apply uptime and yield. With 4 parts × 480 cycles = 1920 gross, at 90% uptime and 97% yield, good capacity is about 1676 units.
What is the difference between gross and good capacity? Gross capacity (1920 here) assumes zero downtime and perfect parts. Good capacity (1676) subtracts 192 units of uptime loss and about 52 units of yield loss to give what you can actually deliver.
Why do uptime and yield both reduce capacity? They hit at different stages — uptime removes whole cycles you never run, and yield removes defective parts within the cycles you do run. Both must be applied, dropping 1920 gross to roughly 1676 good.
What is a realistic first-pass yield for rotomolding? Mature parts often run 95% to 98% first-pass yield; the 97% here is typical for a stable process. New molds or thin-wall parts can sit lower until the cycle is dialed in.
How do I use this for a delivery commitment? Promise against good capacity, not gross. Committing 1900 units when the line delivers 1676 sets you up to miss; quoting near 1676 leaves you able to keep the date.

Last reviewed 2026-05-12.