Cycle time
How to define, measure and use production cycle times without confusing machine time, output pace, takt or elapsed lead time.
Tags: production, planning, time
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In the single-machine example, 30 s automatic time + 10 s load/unload with no overlap gives 40 s/piece running cycle. A 12-minute setup adds 6 s/piece for 120 good pieces or 12 s/piece for 60, giving 46 or 52 s/piece effective time. Total times are 92 and 52 minutes with no other stops. Batch size changes setup allocation. Takt instead measures the pace required by demand.
LEI distinguishes measured machine and operator cycles. The interval between finished units can differ from both. LEI cycle-time lexicon
Name the time being reported
State the operation, resource, revision, start and end events, output per cycle and included losses. Separate measured time from planning allowances.
| Measure | Meaning and boundary |
|---|---|
| Machine cycle | Machine operations for a piece or explicitly identified batch/cavity count |
| Operator cycle | Repeating operator work sequence; may include work shared across machines |
| Effective machine cycle | LEI's machine time plus loading/unloading and changeover time allocated across pieces between changeovers |
| Output interval | Time between successive completions at the stated observation point |
| Production lead time | Elapsed passage through the selected process or value stream, including waiting |
These distinctions follow LEI's terminology; local software fields can use different names. Translate the definition, not just the label, when moving data between systems. LEI time-related terms
Cycle time, takt and lead time
Takt time is available production time divided by customer demand for the same period. It is a required pace, rather than a stopwatch observation. If the available time or demand changes, takt changes even when the machine program does not. A station cycle shorter than takt is useful evidence, but it does not establish that the complete line will meet demand through stoppages, scrap and product changes. LEI takt-time definition
In Minitab Engage's value-stream-map documentation, process cycle time is the interval from one completed output to the next. Its timeline treats inventory and waiting separately; its summary lead time adds inventory time and cycle time. This is a documented software convention, not a promise that adding individual machine program durations predicts a customer's delivery date. Record which timeline convention a report uses. Minitab Engage timeline calculations, undated online documentation
Measure repeatable events and retain variation
A practical measurement specification identifies whether timing starts at load, clamp, program start or first motion, and whether it ends at cycle-complete, unclamp or unload. Use the same event pair across observations. Capture quantity per completion and label aborted cycles, rework passes and missing timestamps rather than silently treating them as ordinary good production.
Keep individual observations when possible. Report sample size, observation period and an appropriate description of spread alongside the average. A short demonstration run does not characterize an entire shift with tool changes and replenishment. Conversely, dividing the whole shift by output does not isolate the machine's running speed. These are measurement-design recommendations: the required sampling and statistical treatment depend on the decision and process variability.
Where operator and automatic work overlap, a timeline is more useful than adding all durations. LEI's standardized-work combination table explicitly represents manual work, walking and machine processing together; its process capacity sheet also considers machine times, tool setup/change intervals and manual work. Use those interactions to check a proposed staffing or capacity calculation. LEI standardized work
Running cycle, ideal cycle and planning allowance
Vorne's OEE guidance defines running cycle time separately from planned and unplanned stops, and distinguishes it from ideal cycle time: the fastest sustainable time under optimal operating conditions. A budgeted rate with losses already included is a different input. Thus a reasonable planning allowance can be an inappropriate ideal-cycle reference for OEE. Vorne cycle-time definitions
In its OEE calculation, performance = ideal cycle time × total count / run time, while quality = good count / total count. Availability accounts for stop time relative to planned production time. Keep the count and time units consistent, and investigate performance above 100% rather than accepting it as an exceptional result. A wrong ideal time or pieces-per-cycle conversion can create that result. Vorne OEE calculations
Do not deduct the same loss twice. If a planning cycle already includes typical downtime, multiplying capacity by another downtime factor can understate output. If setup is explicitly scheduled as a separate block, adding setup per piece again overstates the required time. Vorne's FAQ distinguishes standard/budget cycle time from ideal cycle time for this reason. Vorne OEE FAQ
Original example: one batch, several valid time measures
Assume an invented single-machine job has no overlap: 30 seconds automatic processing and 10 seconds combined load/unload per piece. A 12-minute setup precedes a 120-piece batch. All pieces are good; no other stops occur.
Running cycle = 30 + 10 = 40 s/piece. Setup allocation = 720 / 120 = 6 s/piece. Effective time including that setup = 46 s/piece. Reconciliation: 720 + 120 × 40 = 5520 seconds = 92 minutes, also 120 × 46 = 5520 seconds.
If the same setup instead supports 60 pieces, the allocated setup becomes 12 s/piece and effective time becomes 52 s/piece. The machine has not become slower: the allocation denominator changed. The total job takes 720 + 60 × 40 = 3120 seconds = 52 minutes. These calculations assume the setup occurs once for each stated batch; they do not justify making larger batches without considering demand and inventory.
Now assume a separate full-period record has 420 planned minutes, 60 stop minutes and 510 total pieces, of which 500 pass first time. Run time is 360 minutes = 21,600 seconds. Average running time per total piece is 42.35 seconds; planned time per good piece is 50.4 seconds. Those ratios answer different questions.
Using an independently justified ideal time of 40 s/piece, availability = 360/420 = 85.71%, performance = (40 × 510)/21,600 = 94.44%, and quality = 500/510 = 98.04%. Their product is 79.37% OEE, matching (500 × 40)/(420 × 60). Do not add the earlier batch's setup to this period unless it is actually outside the recorded stop time.
Capacity and scheduling limits
Two identical independent machines might double theoretical output rate, but that assumes enough operators, fixtures, material and downstream capacity. Two sequential operations do not generally double elapsed time per output once production overlaps; first-piece passage and steady output interval are different. Verify the resource timeline before applying either addition or division.
For a planning handoff, preserve the time definition, quantity basis, observed range, setup treatment, loss assumptions and source date. Revisit the record after material, tooling, program, staffing or inspection changes. The sources above are undated living web pages reviewed on 2026-11-01; their current web footer years are not publication editions.