How do you calculate rework throughput?

Divide the returned or rework weight by the handling runtime to get the raw rate, then multiply by the handling efficiency. For 12,000 lb over 6 hr at 82% efficiency, the raw rate is 2,000 lb/hr and effective throughput is 1,640 lb/hr.

Why is effective throughput lower than the raw rate?

Raw rate assumes continuous flow. Real re-handling loses time to blend metering, plugged transitions, moisture or screening variation, and sharing equipment with primary production. The 82% factor drops 2,000 lb/hr to 1,640 lb/hr.

What is a good rework handling efficiency?

Free-flowing dry screenings can run 85-92%, while sticky, high-fat, or moisture-variable feed returns often fall to 70-80%. The 82% default is a reasonable mid-range for blended feed rework.

Should rework run during production or in a separate window?

If effective throughput (1,640 lb/hr) clears your accumulated rework within available slack time, blend it in. If the volume is large or the blend ratio is tight, schedule a dedicated window so it doesn't starve first-pass throughput.

How does blend ratio affect feed return?

This calculator gives the handling rate, not the allowable inclusion. If specs cap rework at, say, 5% of a clean lot, your true ceiling may be lower than 1,640 lb/hr — check the blend limit before scheduling.

Does moisture in returned feed change the math?

Yes, indirectly. Wet or caked returns slow flow and plug transitions, which shows up as lower handling efficiency. Drop the efficiency percent rather than the weight if moisture is the issue.

Grain Milling, Dry Bulk Food & Feed Handling calculator

Rework/Feed Return Calculator

Rework and feed-return throughput is the effective rate, in pounds per hour, at which a mill re-introduces off-spec product, screenings, fines, or customer-returned feed back into the process. Production planners and operations managers at flour, corn, and feed mills use it to decide whether rework can be absorbed during normal runs or needs a dedicated window. It matters because rework competes with first-pass production for conveyors, surge capacity, and mixer time, and the nameplate rate is never what you actually get. Applying a handling-efficiency factor turns an optimistic raw rate into a number you can schedule against.

What this calculator does

Estimate the practical rate for rework or feed return processing by comparing returned product weight with runtime and rework handling efficiency.
Use it when off-spec feed, fines, pellet returns, screened material, customer returns, or in-process rework must be routed back through grinding, mixing, pelleting, or loadout.
It computes effective rework throughput in lb/hr by dividing the rework weight by handling runtime, then derating for handling efficiency.

Formula used

Raw rework/feed return throughput = returned or rework weight ÷ rework handling runtime
Effective rework/feed return throughput = raw throughput × rework handling efficiency

Inputs explained

Returned or rework weight to re-handle:
Rework handling runtime:
Rework handling efficiency:

How to use the result

Use it when planning to blend off-spec lots, screenings, or returned feed back into production and you need a realistic re-handling rate.
It assumes the efficiency factor captures all losses; surge-bin bottlenecks, blend-ratio limits that cap how much rework a clean lot can absorb, and quality holds are not modeled.

Current U.S. benchmarks

The producer price index for steel mill products stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. Quotes priced off last quarter's material cost miss this move.
Industrial natural gas averages $4.9 per Mcf (EIA, Apr 2026), down 7.7% from a year earlier, with industrial electricity at 8.66 cents per kWh. Process heating and refrigeration budgets track both.
The U.S. has 17,154 machine shops establishments employing about 223,303 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate rework throughput? Divide the returned or rework weight by the handling runtime to get the raw rate, then multiply by the handling efficiency. For 12,000 lb over 6 hr at 82% efficiency, the raw rate is 2,000 lb/hr and effective throughput is 1,640 lb/hr.
Why is effective throughput lower than the raw rate? Raw rate assumes continuous flow. Real re-handling loses time to blend metering, plugged transitions, moisture or screening variation, and sharing equipment with primary production. The 82% factor drops 2,000 lb/hr to 1,640 lb/hr.
What is a good rework handling efficiency? Free-flowing dry screenings can run 85-92%, while sticky, high-fat, or moisture-variable feed returns often fall to 70-80%. The 82% default is a reasonable mid-range for blended feed rework.
Should rework run during production or in a separate window? If effective throughput (1,640 lb/hr) clears your accumulated rework within available slack time, blend it in. If the volume is large or the blend ratio is tight, schedule a dedicated window so it doesn't starve first-pass throughput.
How does blend ratio affect feed return? This calculator gives the handling rate, not the allowable inclusion. If specs cap rework at, say, 5% of a clean lot, your true ceiling may be lower than 1,640 lb/hr — check the blend limit before scheduling.

Last reviewed 2026-05-12.