First Time Through (FTT) in Manufacturing: Formula, PPM, and Action Playbook

FTT definition and formulas

• FTT % = (First-time good quantity / Produced quantity) x 100
• FTT PPM = (First-time defect quantity / Produced quantity) x 1,000,000

• Produced quantity = Good + Rework + Rejection
• First-time good quantity = Units passing all required checks without rework
• First-time defect quantity = Units failing first-pass checks before any recovery

• Keep denominator logic identical across lines and models.
• Do not merge first-time defects into rework-recovered totals for FTT.
• If produced quantity is zero, return null and flag a data quality exception.

Defect taxonomy that makes FTT actionable

• Defect family (for example: dimensional, cosmetic, assembly, electrical)
• Defect reason code under each family
• Defect remark template (station, symptom, suspected cause)
• Optional severity tag (critical, major, minor)

• Add new reason codes through controlled master updates.
• Keep names stable to protect trend integrity.
• Require remarks for repeat or high-impact defect reasons.

Data model required for shift-level FTT control

• Production fact: date, shift, line, model, good qty, rework qty, reject qty
• Defect fact: date, shift, line, model, family, reason code, defect qty, remark
• Plan fact: shift target and cumulative target

• Line master
• Shift master
• Model master
• Defect family and reason-code masters

• Use date + shift + line + model as the minimum operational key.
• Enforce the same key usage in all quality and output widgets.

How to read FTT in a line dashboard

• KPI cards: FTT %, FTT PPM, reject qty, rework qty
• Pivot: line vs shift vs model for defect concentration
• Query widget: top reason codes by quantity and recurrence
• Plan panel: output variance with quality variance

• FTT < 92%: immediate containment
• FTT 92% to 97%: moderate instability, focused corrective action
• FTT > 97%: controlled first-pass quality in many discrete settings
• FTT PPM > 20,000: root-cause escalation within shift cycle
• FTT PPM 5,000 to 20,000: recurring-defect action plan required
• FTT PPM < 5,000: healthy operating range for many lines

Shift-level escalation loop for quality teams

1. Shift handoff reviews prior FTT %, FTT PPM, and unresolved reasons.
2. Supervisor triggers containment when thresholds are breached.
3. Top defect family is assigned to quality, process, or maintenance owner.
4. Corrective action and due time are logged.
5. Next shift validates recurrence reduction before closure.

• Maintenance route: machine wear, calibration drift, equipment instability
• Process route: setup sequence, instruction variance, method gaps
• Quality route: incoming material variation, inspection escape patterns

FTT and OEE should be reviewed together

1. Track OEE trend by line.
2. Overlay FTT and FTT PPM trend.
3. Identify lines with stable OEE but declining FTT.
4. Prioritize defect-family action before speed optimization.

Quick implementation roadmap

• Standardize FTT formula and denominator logic
• Freeze defect taxonomy and reason-code masters
• Baseline shift-level FTT dashboard

• Enable threshold alerts for FTT and FTT PPM
• Run daily recurring-defect review cadence
• Start closure tracking by owner

• Add predictive checks for recurring defect patterns
• Connect FTT trend to plan-attainment and labor reviews
• Recalibrate thresholds by product family

Frequently Asked Questions