OEM is stable, yet sub-tier suppliers feel brittle
Question
Our OEM schedule adherence is green and primary suppliers hit OTIF. But expedites and premium freight keep rising, a few parts are effectively single-sourced at tier-2, lead-times wobble after small shocks, and QA escapes bunch after volume ramps. Why does the chain feel fragile when our direct suppliers look fine?
Answer ✅
Direct-supplier totals can mask sub-tier instability. If tier-2 capacity is tight, cash cycles lengthen, single-source parts creep in, or change orders ripple downstream, you can “hit OTIF” while delivery becomes luck-dependent. SSM-Audit adds a stability band beside the KPIs you already track so you see whether the chain is calm and repeatable—or brittle beneath your green dashboards.
What the bands would have shown 📊
• Lead-time stability sliding A+ -> A0 (more variance at tier-2/tier-3)
• OTIF stability degrading to A- on critical paths (meets average, misses bunch)
• Tier-2 capacity cadence weakening A0 -> A- (utilization clusters near 95%+)
• Single-source concentration tilting A0 -> A- (effective mono-source for key parts)
• Supplier financial health stability dipping A0 -> A- (DSO stretch, aging payables)
• Quality-escape stability softening A+ -> A0 (post-ramp escapes and rework)
What to do now 🛠️
- Band the sub-tier panel: lead-time stability, OTIF stability, tier-2 capacity cadence, single-source concentration, supplier financial health, quality-escape stability—review weekly on your top 50 parts.
- De-risk single sources: when concentration band < A0, dual-qualify or pre-build buffer stock; protect tools and dies.
- Stabilize capacity: if tier-2 cadence band < A0, shift demand to parallel lines, pre-book critical shifts, and stagger ramps.
- Cashflow hygiene: when financial health band < A0, tighten payment terms upstream and offer targeted early-pay programs.
- Lead-time guardrails: if lead-time band < A0, freeze late design churn, split releases, and widen pull-ahead windows.
- Quality loop: where escape band slips, add canary tests and temporary incoming inspection; lock change control.
How SSM-Audit helps (practicalities) 🌟
• No additional infrastructure: runs beside ERP/MRP, ASN/OTIF reports, and QA logs.
• Numbers unchanged: OTIF, lead-times, and quality counts remain as-is; stability is a read-only overlay.
• Easy to use: spreadsheet/BI friendly; a tiny weekly ritual with sourcing, planning, and QA.
• Universal language: A++ / A+ / A0 / A- / A– aligns OEM, tier-1s, and sub-tiers fast.
CLI 💻 — try our mini Calculator to identify the drift
(Mini CLI Download Page)
Feed your CSVs and see bands and drift at a glance (numbers unchanged).
# Lead-time stability (requested -> promised -> actual)
ssm_audit_mini_calc supply.csv --kpi "Lead-Time Stability" \
--out bands_leadtime.csv --plot_kpi "Lead-Time Stability" --build_id sup
# OTIF stability (on-time-and-in-full, critical-only)
ssm_audit_mini_calc supply.csv --kpi "OTIF Stability" \
--out bands_otif.csv --plot_kpi "OTIF Stability" --build_id sup
# Tier-2 capacity cadence (utilization vs ramps)
ssm_audit_mini_calc supply.csv --kpi "Tier-2 Capacity Cadence" \
--out bands_t2cap.csv --plot_kpi "Tier-2 Capacity Cadence" --build_id sup
# Single-source concentration (HHI/effective sources)
ssm_audit_mini_calc supply.csv --kpi "Single-Source Concentration" \
--out bands_single.csv --plot_kpi "Single-Source Concentration" --build_id sup
# Supplier financial health stability (aging, DSO, covenant flags)
ssm_audit_mini_calc supply.csv --kpi "Supplier Financial Health Stability" \
--out bands_fin.csv --plot_kpi "Supplier Financial Health Stability" --build_id sup
# Quality-escape stability (post-ramp escapes/rework)
ssm_audit_mini_calc supply.csv --kpi "Quality-Escape Stability" \
--out bands_quality.csv --plot_kpi "Quality-Escape Stability" --build_id sup
# Expedite/premium freight rate (stress proxy)
ssm_audit_mini_calc supply.csv --kpi "Expedite Rate" \
--out bands_expedite.csv --plot_kpi "Expedite Rate" --build_id sup
Outputs you will get:
• CSVs with stability bands for each timestamp (e.g., bands_leadtime.csv).
• Drift charts per KPI (--plot_kpi) showing exactly where sub-tier fragility appears first.
• Optional alerts if you enable thresholds in your setup.
Technical notes
Representation: x = (m, a) with a in (-1, +1)
Collapse parity: phi((m,a)) = m
Order-invariant pooling:
U = sum(w_i * atanh(a_i))
W = sum(w_i)
a_out = tanh( U / max(W, eps_w) )
Typical bands (example):
A++: a >= 0.75
A+: 0.50 - 0.75
A0: 0.25 - 0.50
A-: 0.10 - 0.25
A--: a < 0.10
Navigation
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Page disclaimer
Illustrative scenario for research and education. Observation-only; do not use for critical decisions without independent validation.
SHUNYAYA 