Why multiply uptime and yield separately?

They remove different parts of the same gross count. Downtime parts are never ground, while yield loss parts are ground and then rejected, so the two losses add to the unfilled target rather than overlapping.

Should rework count as accepted output?

No. First-pass yield excludes reworked parts by definition, so the rework row is the count that needs a second pass or scrap. Bank only parts that passed at the first attempt when you compare with the target.

What does the L10 limit mean here?

Nothing about this run. L10 describes how long a bearing population lasts in service, not how many parts a grinder accepts today. The page counts output; bearing life needs load and speed data from the application.

Does higher uptime always raise output?

Only while yield holds. Uptime and yield multiply, so a shift that trades uptime for more rework can leave accepted parts flat or lower. Check both columns before crediting an uptime gain.

Bearings, Gears & Power Transmission calculator

Bearing Grinding Throughput Calculator

Turn a grinding schedule into accepted parts: multiply parts per cycle by available cycles, then derate for grinding cell uptime and first-pass yield. The page shows where the losses land and how far the total sits from your target.

What this calculator does

Accepted bearing parts from a grinding run after uptime and first-pass yield, with the shortfall against your target called out.

Formula used

Gross parts = bearing parts per grinding cycle × available grinding cycles
Accepted parts = gross parts × grinding uptime ÷ 100 × first-pass yield ÷ 100
Parts lost to downtime = gross parts × (1 − grinding uptime ÷ 100)
Parts needing rework or scrap = gross parts × uptime ÷ 100 × (1 − first-pass yield ÷ 100)
Shortfall to target = target accepted parts − accepted parts

Inputs explained

Bearing Parts per Grinding Cycle: Loaded parts per cycle from the grinding cell setup sheet.
Available Grinding Cycles: Cycles the schedule makes available for this run.
Grinding Cell Uptime: Measured running share of scheduled grinding cell time.
First-Pass Grinding Yield: Good parts on the first pass, measured from cell records.
Target Accepted Parts: Accepted parts the plan requires, from the demand forecast.

How to use the result

Best suited to checking a grinding line against demand, sizing the effect of an uptime project, explaining rework volume to planning.
Counts good parts, not bearing life: L10 is the fatigue duration at which ten percent of bearings fail. One yield for the whole run; size changes and wheel dressing cycles vary it.

Current U.S. benchmarks

The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

Why multiply uptime and yield separately? They remove different parts of the same gross count. Downtime parts are never ground, while yield loss parts are ground and then rejected, so the two losses add to the unfilled target rather than overlapping.
Should rework count as accepted output? No. First-pass yield excludes reworked parts by definition, so the rework row is the count that needs a second pass or scrap. Bank only parts that passed at the first attempt when you compare with the target.
What does the L10 limit mean here? Nothing about this run. L10 describes how long a bearing population lasts in service, not how many parts a grinder accepts today. The page counts output; bearing life needs load and speed data from the application.
Does higher uptime always raise output? Only while yield holds. Uptime and yield multiply, so a shift that trades uptime for more rework can leave accepted parts flat or lower. Check both columns before crediting an uptime gain.

Related guides

Last reviewed 2026-10-01.