Why the Plant Called for an Audit
The plant manager had a clear problem: line OEE was reported at 74% but actual throughput felt lower. The maintenance team was responding to breakdowns but the same machines kept stopping. Consumable spend was rising without a clear explanation. A previous vendor review had resulted in a recommendation to replace two machines — at Rs 18 lakh capital. Before approving the spend, the plant manager asked for an independent assessment.
Audit Scope and Method
The audit covered all five packaging lines over two production shifts. Line OEE was measured directly during the audit rather than relying on self-reported data. Downtime was logged in real time by cause category. Consumable stock and purchase records were reviewed. Machine settings and maintenance logs were checked against manufacturer specifications.
Root Cause 1: OEE Measurement Error
The reported 74% OEE was inflated. The plant was measuring availability against planned production time, but not including breaks, shift changeovers and short stoppages below 5 minutes. When measured to industry standard (all time — all stoppages including microbreaks), actual OEE on the primary line was 58%. The gap between reported and actual OEE — 16 percentage points — represented Rs 9.5 lakh per year in understated production loss.
This was not deliberate misreporting. The plant simply did not have a standardised OEE measurement methodology. Introducing a proper measurement baseline was the first deliverable — because you cannot improve what you are not measuring correctly.
Root Cause 2: CIJ-Induced Line Stoppages — Wrong Ink Grade
Line 3 was stopping 4–6 times per shift for CIJ print quality issues — incomplete characters, satellite drops, nozzle clog warnings. Each stoppage averaged 8 minutes. At 5 stoppages per shift, 3 shifts, 26 days — this was 156 hours of downtime per year on one line. At a contribution of Rs 800 per minute for that line's output, this was Rs 7.5 lakh per year.
Root cause: the ink grade in use had been changed 8 months earlier to a "performance grade" recommended by the vendor's service engineer, which had higher viscosity than the original specification. The higher viscosity was incompatible with the machine's jetting system at the plant's ambient temperature. Reverting to the original specification eliminated the fault pattern within one shift of the audit — without any machine change.
Root Cause 3: Checkweigher Reject Rate 3x Above Benchmark
Line 2's checkweigher was rejecting 3.1% of packs — against a benchmark of 0.8–1.2% for this product type. At Rs 12 per pack content and 180,000 packs per month, the reject and rework cost was Rs 4.7 lakh per year in product write-off and labour.
Root cause investigation: the checkweigher was calibrated against a static weight but the filler on Line 2 had a +3g drift on the high side due to a worn dosing head. The checkweigher was correctly reading what it received — the problem was upstream. Resetting the filler dosing head reduced the reject rate to 0.9% within 3 days. No new equipment was needed.
What the Vendor Had Recommended vs What Was Actually Wrong
| Issue | Vendor Recommendation | Audit Finding |
|---|---|---|
| Low line throughput | Replace two machines (Rs 18 lakh) | OEE measurement error — no machine change required |
| CIJ downtime on Line 3 | Service contract upgrade (Rs 1.2 lakh/year) | Wrong ink grade — revert to original specification |
| Checkweigher rejects | Replace checkweigher (Rs 6.5 lakh) | Filler dosing head drift — Rs 8,000 repair |
Total capital spend recommended by vendor: Rs 24.5 lakh + Rs 1.2 lakh/year. Total capital spend after independent audit: Rs 0. Total recoverable value identified: Rs 21.7 lakh per year.
18-Month Improvement Roadmap
- Immediate (Week 1–2): Ink grade reversion on Line 3. Filler dosing head repair. OEE measurement methodology implemented across all 5 lines.
- Short term (Month 1–3): Downtime Pareto baseline established. Top 5 causes by cost addressed through PM adjustment. Consumable spend review completed.
- Medium term (Month 3–9): Structured PM schedule implemented across all 5 lines. Consumable contracts renegotiated. OEE target of 68% set for primary line.
- Longer term (Month 9–18): Technology upgrade evaluation for CIJ-to-TTO conversion on Lines 3 and 4 — capital justification with payback model.