How do you calculate core making capacity?

Multiply cores per machine cycle by available cycles to get gross capacity, then multiply by core machine availability and accepted core yield. With 4 cores/cycle over 420 cycles at 86% availability and 95% yield, good capacity is 1,372.56 cores.

What is the difference between gross and good core capacity?

Gross capacity is the theoretical maximum if nothing went wrong, 1,680 cores in the example. Good capacity, 1,372.56 cores, is what you can actually ship to the molding line after losing 235.2 cores to downtime and 72.24 to rejects.

What is a good accepted core yield?

Well-run cold-box and shell core lines typically run 95-98% accepted yield; the 95% in the example is solid. Lower yields usually point to friable cores, broken-out detail, or gas-related blows that need binder or vent attention.

Why does core machine availability matter so much?

It directly scales output. At 86% availability you lose 235.2 cores per planning window to changeovers, blow-tube cleaning, and tooling faults, more than three times the reject loss in this example. Improving availability often beats chasing yield.

How do I use this for line balancing?

Compare good core capacity against the molding line's demand for that casting. If a part needs three cores per mold and the line pours 500 molds, you need 1,500 good cores, meaning the 1,372.56 here would short the line and the core room is the bottleneck.

Should I count cycles or hours?

Use cycles when the machine output is set by tooling and blow time; this is more accurate than hours because a cycle delivers a fixed core count regardless of small timing variation. Convert your shift length to available cycles at the machine's rated cycle time.

Foundry & Forging calculator

Core Making Capacity Calculator

Core making capacity is the number of good, usable sand cores a coremaking cell can actually deliver after machine downtime and core rejects are accounted for. Foundry planners and core-room supervisors use it to confirm the core shop can feed the molding line without becoming the bottleneck, because a casting that needs internal passages cannot be poured until its core is ready. It matters most when ramping a new program or running multi-core castings, where one short cell starves the whole pour schedule. This calculator splits the gross capacity from the real good-core output so you can see exactly how much is lost to availability versus reject.

What this calculator does

Estimate good coremaking capacity for sand cores, shell cores, cold-box cores, or core assemblies.
Use it when core room output must match mold demand, pouring schedule, or customer lots.
It computes good core making capacity by discounting gross capacity for core machine availability and accepted core yield, and reports the downtime and reject losses separately.

Formula used

Gross core making capacity = cores per machine cycle × available coremaking cycles
Good core making capacity = gross capacity × core machine availability × accepted core yield

Inputs explained

Cores per machine cycle:
Available coremaking cycles:
Core machine availability:
Accepted core yield:

How to use the result

Use it during line balancing, new-program ramp planning, or when a molding line is waiting on cores and you need to know whether the core room can keep up.
It assumes the cycle count and cores-per-cycle are steady; if you run a mix of single-core and multi-core tooling on the same machine, run the calculation per tool set rather than blended.

Current U.S. benchmarks

The producer price index for steel mill products stands at 374.203 (BLS, Jul 2026), up 22.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 3,569 primary metal manufacturing establishments employing about 354,911 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate core making capacity? Multiply cores per machine cycle by available cycles to get gross capacity, then multiply by core machine availability and accepted core yield. With 4 cores/cycle over 420 cycles at 86% availability and 95% yield, good capacity is 1,372.56 cores.
What is the difference between gross and good core capacity? Gross capacity is the theoretical maximum if nothing went wrong, 1,680 cores in the example. Good capacity, 1,372.56 cores, is what you can actually ship to the molding line after losing 235.2 cores to downtime and 72.24 to rejects.
What is a good accepted core yield? Well-run cold-box and shell core lines typically run 95-98% accepted yield; the 95% in the example is solid. Lower yields usually point to friable cores, broken-out detail, or gas-related blows that need binder or vent attention.
Why does core machine availability matter so much? It directly scales output. At 86% availability you lose 235.2 cores per planning window to changeovers, blow-tube cleaning, and tooling faults, more than three times the reject loss in this example. Improving availability often beats chasing yield.
How do I use this for line balancing? Compare good core capacity against the molding line's demand for that casting. If a part needs three cores per mold and the line pours 500 molds, you need 1,500 good cores, meaning the 1,372.56 here would short the line and the core room is the bottleneck.

Last reviewed 2026-07-13.