๐ฏ The 3 Classification Axes
Every fitment gap/levelness issue at ASSB falls into one of three axes. Classify first, then apply the standard fix tree.
Gap between two assembled components.
Tolerance: Gap โค 0.5mm ยท Level โค 0.5mm
Typical root cause: sub-component supplier variation, locator wear, clip fatigue.
Gap between a panel and a body opening.
Tolerance: Gap โค 1.0mm ยท Level โค 1.0mm
Typical root cause: panel locator drift, fixture clamp wear, sensor calibration, paint thickness variation.
Gap between major body sections.
Tolerance: Gap โค 1.5mm ยท Level โค 1.5mm
Typical root cause: BIW fixture tolerance stack, weld gun drift, hemming force variation.
๐ฏ 4-Layer Architecture
Purpose: Input data + requirement table โ analyse failure part/process โ predict future failures via statistics.
Layer 1 โ Predetermined Requirement Table
Joint ID | Axis | Class | Spec | Min | Max | Measurement method
HL_FD | PรB | A | Gap | 0.0 | 1.0 | Feeler 1.0mm
BD_RR | BรB | B | Gap | 0.0 | 1.5 | Optical scanner
... (~50+ joints)
Layer 2 โ Data Input (line operators)
Web form + CSV upload + (optional) SPC API feed. Each row: Joint ID, value, inspector, station, VIN, timestamp, photo.
Layer 3 โ Analysis Engine (Python / SQLite)
Runs on sir's VPS. Computes:
- Out-of-spec detection โ joint, frequency, severity (ฯ level)
- Pareto โ top 10 failing joints (80/20)
- Failure mode clustering โ which process step concentrates misses
- SPC trend โ X-bar / R-chart + Western Electric rule violations
- Weibull forecast โ P(failure within next N units)
- 5-Whys auto-suggest โ most-likely root cause from pattern
Layer 4 โ Output & Alerts
Daily Telegram push + auto-filled 5-Whys template + TBP project auto-feed + weekly trend email.
๐ ๏ธ Tech Stack (sir's existing VPS, $0 cost)
Port 8106, mobile-friendly
SQLite for measurements
SPC, Weibull, Pareto, charts
Daily digest, alerts
1. Part ร Part โ fitment miss
Why 1: Gap exceeds 0.5mm โ Why 2: Component dimension out of spec? โ Why 3: Supplier lot variation / locator wear? โ Why 4: Incoming inspection not catching? โ Why 5: Gauge calibration overdue or fixture wear?
2. Part ร Body โ fitment miss
Why 1: Gap exceeds 1.0mm โ Why 2: Panel locator drift or body opening out of position? โ Why 3: BIW fixture wear / hemming force? โ Why 4: Preventive maintenance interval missed? โ Why 5: PM schedule not tied to actual wear data?
3. Body ร Body โ fitment miss
Why 1: Gap exceeds 1.5mm โ Why 2: Weld gun drift or BIW fixture clamp wear? โ Why 3: Weld schedule parameter out of range? โ Why 4: Weld tip dressing interval missed? โ Why 5: SPC data not fed back to PM schedule?
๐ Reference to Toyota K-Standard
Toyota K-standard (TMC engineering specification) defines gap/levelness tolerance bands by joint class:
| Joint Class | Gap | Levelness | Examples |
|---|---|---|---|
| Class A (visible exterior) | โค 1.0mm | โค 1.0mm | Hood-fender, door-body, headlamp-fender |
| Class B (semi-visible) | โค 1.5mm | โค 1.5mm | Back door - side member, IP - console |
| Class C (hidden / interior) | โค 2.0mm | โค 2.0mm | IP upper - lower, console - duct |
โ Sir to confirm K-standard reference + ASSB plant-specific tightening (if any).
๐ Why This Matters for Plant Director Track
Every fitment miss is a potential 0 COP event under sir's TBP theme:
- Customer claim: Class A gap > 1.5mm triggers warranty scrutiny
- IATF 16949 audit finding: Clause 8.5.1.1 โ control plan not followed if gap drift not detected
- Stop-shipment: Severe cases (e.g. headlamp not sealing, water leak)
This 3-axis classification = TBP project Step 2 (Grasp Current Situation) evidence. The fix trees = Step 4 (Establish Countermeasures).