Endline Inspection SOPs, DHU Calculation & Daily Defect Logs
Lesson Contents Overview
Learning Objectives
Comprehensive Technical GuidanceTextbook & Training SOP
Endline Inspection SOPs, DHU Calculation & Daily Defect Logs
═══════════════════════════════════════════════════════════════════════════════ MODULE 05: INLINE, ENDLINE & FINAL INSPECTION SOPS LESSON 05.02: ENDLINE INSPECTION SOPS, DHU CALCULATION & DAILY DEFECT LOGS ═══════════════════════════════════════════════════════════════════════════════ [Course: AQL 2.5 Quality Inspection & QA Masterclass] [⏮️ Previous: 05.01 Inline QA | Next: 05.03 Final Random Inspection ➡️]
1. Introduction: The 100% Quality Screening Gate
While Inline Inspection acts as a roving preventative check at the sewing needle, Endline Quality Inspection represents the absolute 100% screening gate at the exit of every sewing line.
Before any assembled garment moves downstream to washing, embroidery, iron pressing, or polybag packaging, it must pass through an exhaustive physical and visual audit by certified Endline QC personnel.
┌─────────────────────────────────────────────────────────────────────────────┐ │ THE 100% ENDLINE SCREENING GATE │ │ │ │ [SEWING ASSEMBLY OUTPUT (100%)] ──► [ENDLINE INSPECTION STATION] │ │ │ │ │ ┌──────────────────────────┴────────┐ │ │ ▼ ▼ │ │ [100% PASSED GARMENTS] [DEFECTIVE GARMENTS] │ │ ├── First-Quality Garments ├── Tagged with Red Arrow │ │ ├── Right-First-Time (RFT) ├── Logged on Hourly Sheet │ │ └── Sent to Finishing / Wash └── Sent to Repair Rack │ └─────────────────────────────────────────────────────────────────────────────┘
2. Mathematical Breakdown: DHU vs. Defective Rate vs. AQL
Understanding the mathematical distinction between DHU, Defective Rate (% Defective), and AQL is fundamental to apparel quality engineering:
┌─────────────────────────────────────────────────────────────────────────────┐ │ CRITICAL QUALITY METRIC COMPARISON MATRIX │ ├────────────────────┬────────────────────────────────────┬───────────────────┤ │ METRIC │ MATHEMATICAL FORMULA │ WHAT IT MEASURES │ ├────────────────────┼────────────────────────────────────┼───────────────────┤ │ 1. DHU │ (Total Defects / Total Units) * 100│ Total defect count│ │ (Defects per 100) │ (Can exceed 100% if multi-defects) │ & process density │ ├────────────────────┼────────────────────────────────────┼───────────────────┤ │ 2. Defective Rate │ (Defective Garments / Total) * 100 │ Percentage of pcs │ │ (% Defective) │ (Maximum cap is 100%) │ needing rework │ ├────────────────────┼────────────────────────────────────┼───────────────────┤ │ 3. AQL │ Statistical Acceptance Sampling │ Commercial lot │ │ (ISO 2859-1) │ (Sample Size, Ac, Re thresholds) │ pass/fail release │ └────────────────────┴────────────────────────────────────┴───────────────────┘
Step-by-Step DHU Numerical Calculation Example:
extTotal Garments Inspected = 500 ext pieces extGarments with Defects = 35 ext pieces extTotal Defects Counted Across All Defective Pieces = 42 ext defects
mathbfDHU = left( rac42500 ight) imes 100 = mathbf8.40% quad ext(8.4 defects per 100 units) mathbf% ext Defective = left( rac35500 ight) imes 100 = mathbf7.00% quad ext(7.0% of garments need repair)
3. The Standardized 7-Point Clockwise Garment Inspection SOP
To inspect a garment completely inside and out in under 45 to 60 seconds without missing critical seam intersections, endline QC inspectors execute the 7-Point Clockwise Method:
┌─────────────────────────────────────────────────────────────────────────────┐ │ THE 7-POINT CLOCKWISE INSPECTION SEQUENCE │ │ │ │ [1. COLLAR & NECKBAND] │ │ (Point balance & SPI) │ │ ╱ ╲ │ │ [6. LEFT SHOULDER & BACK] [2. RIGHT SHOULDER & ARMHOLE] │ │ (Yoke balance & pleats) (Shoulder seam & sleeve head) │ │ │ │ │ │ [5. LEFT SLEEVE & CUFF] [3. RIGHT SLEEVE & CUFF] │ │ (Placket, button, length) (Underarm overlock & cuff) │ │ ╲ ╱ │ │ [4. FRONT PLACKET & HEM] │ │ (Buttons, hem wave, alignment) │ │ │ │ ═════════════════════════════════════════════════════════════════════════ │ │ ►► STEP 7: INVERT GARMENT (100% Inside Seams, Looper Threads & Labels) ◄◄ │ └─────────────────────────────────────────────────────────────────────────────┘
4. Structuring the Hourly Endline Defect Log & Pareto Analysis
A factory Daily Defect Log records every defect by category every hour:
┌─────────────────────────────────────────────────────────────────────────────┐ │ PARETO 80/20 ROOT CAUSE DEFECT ANALYSIS │ │ │ │ DEFECT CATEGORY DEFECT COUNT PERCENTAGE CUMULATIVE % │ │ ───────────────────────────────────────────────────────────────────── │ │ 1. Open Seam 184 46.0% 46.0% ▲ │ │ 2. Skipped Stitches 112 28.0% 74.0% │ 80% │ │ 3. Seam Puckering 48 12.0% 86.0% ▼ ZONE │ │ 4. Uneven Hem 24 6.0% 92.0% │ │ 5. Broken Stitch 16 4.0% 96.0% │ │ 6. Other Flaws 16 4.0% 100.0% │ │ ───────────────────────────────────────────────────────────────────── │ │ TOTAL 400 100.0% │ │ │ │ * CONCLUSION: Eliminating Open Seams & Skipped Stitches fixes 74% of all │ │ factory quality defects! │ └─────────────────────────────────────────────────────────────────────────────┘
5. Visual Asset Generation Prompt
6. Summary & Key Takeaways
- 100% Screening: Endline inspection audits 100% of fully assembled garments before finishing, isolating defectives for immediate unpicking.
- True Defect Density (DHU): $DHU = (Total Defects / Total Inspected) × 100$; accounts for multiple flaws on single garments.
- 7-Point Clockwise Sequence: Ensures 100% outside and inside coverage of every garment in 45–60 seconds.
- Hourly Pareto Feedback: Track hourly defect tallies to isolate the vital 20% root causes driving 80% of line rework.
- Target Benchmarks: Strive for factory DHU $< 3.0% and Right-First-Time (RFT) $> 95%.
1. DHU vs. Defective Rate vs. Defect Rate vs. AQL Comparison Matrix
| Quality Metric | Formula / Definition | Scope & Frequency | Key Purpose in Garment QA |
|---|---|---|---|
| DHU (Defects per Hundred Units) | (Total Defects Found / Total Units Inspected) * 100 | 100% Continuous inspection at end of sewing line | Measures true total defect density (can exceed 100% if multiple defects per piece) |
| Defective Rate (% Defective) | (Defective Garments / Total Units Inspected) * 100 | 100% Continuous inspection or sample batch | Measures the proportion of garments requiring repair/rework (maximum 100%) |
| Defect Percentage (%) | (Total Defects / Total Units Inspected) * 100 | Synonymous with DHU in standard apparel engineering | Expresses defect load as a percentage value |
| AQL (Acceptable Quality Limit) | Statistical sampling plan under ISO 2859-1 / ANSI Z1.4 | Random sample batch before shipment (FRI) | Determines commercial lot acceptance or rejection for export |
2. Standard Hourly Endline Defect Log & DHU Calculation Template
| Time Window | Output Inspected (Pcs) | Defect Breakdown (Codes) | Total Defects (D) | Defective Garments (d) | Hourly DHU (%) | Line Status |
|---|---|---|---|---|---|---|
| 08:00 – 09:00 | 120 | Open Seam (3), Skipped Stitch (2) | 5 | 4 | 4.17% | 🟢 Normal |
| 09:00 – 10:00 | 135 | Puckering (2), Loose Thread (4) | 6 | 5 | 4.44% | 🟢 Normal |
| 10:00 – 11:00 | 140 | Open Seam (8), Skipped (5), Needle Cut (3) | 16 | 11 | 11.43% | 🔴 High Alert (CAPA) |
| 11:00 – 12:00 | 130 | Open Seam (2), Skipped Stitch (1) | 3 | 3 | 2.31% | 🟢 Resolved |
| 13:00 – 14:00 | 145 | Shade Var (1), Uneven Hem (2) | 3 | 3 | 2.07% | 🟢 Normal |
| 14:00 – 15:00 | 150 | Loose Thread (3), Oil Spot (2) | 5 | 4 | 3.33% | 🟢 Normal |
| 15:00 – 16:00 | 140 | Skipped Stitch (2), Raw Edge (1) | 3 | 3 | 2.14% | 🟢 Normal |
| 16:00 – 17:00 | 120 | Open Seam (1), Puckering (2) | 3 | 3 | 2.50% | 🟢 Normal |
| DAILY TOTAL | 1,080 pcs | Total Defects Across All Hours | 44 defects | 36 defective pcs | 4.07% DHU | PASS (Target < 5%) |
3. The 7-Point Clockwise Garment Inspection SOP
| Inspection Step | Garment Zone Audited | Key Quality Checks | Target Time Allowance |
|---|---|---|---|
| Point 1: Collar / Neck | Collar points, neckband, collar stand, neck rib | Collar balance, notch alignment, topstitch SPI, rib wave | 6 – 8 Seconds |
| Point 2: Right Shoulder & Armhole | Right shoulder seam, front/back armhole, sleeve head | Seam flat, no gathers, overlock chaining caught | 5 – 6 Seconds |
| Point 3: Right Sleeve & Cuff | Right sleeve underarm seam, cuff placket, bartack | Placket symmetry, cuff button alignment, no needle cuts | 6 – 8 Seconds |
| Point 4: Front Placket & Bottom Hem | Center front placket, buttons/holes, bottom hem | Placket straightness, button spacing, hem SPI, puckering | 8 – 10 Seconds |
| Point 5: Left Sleeve & Cuff | Left sleeve underarm, cuff placket, cuff band | Sleeve length symmetry with right sleeve, clean seams | 6 – 8 Seconds |
| Point 6: Left Shoulder & Back Panel | Left shoulder seam, back yoke, pleats, back body | Yoke balance, back pleat symmetry, fabric flaws | 5 – 6 Seconds |
| Point 7: Inside-Out 100% Seam Check | Full interior: overlock, safety chain, care label | Label placement, thread unravelling, raw edges, loose threads | 10 – 14 Seconds |
Practical Commercial Flow
An Endline QC Inspector at a denim factory in Ashulia, Bangladesh audited the 2:00 PM to 3:00 PM hourly output on Sewing Line 08 producing Men's 5-Pocket Slim Denim Jeans:
Factory Real-Life Scenario
Scenario: A woven shirt factory in Chittagong struggled with high finishing rework costs and late export shipments. The finishing department was receiving 22% defective shirts from the sewing floor every day, overwhelming the repair team.
Solution: The factory revamped its Endline Inspection SOP: instituted 100% dual-mannequin 7-point clockwise inspection, implemented standard Daily Defect Tally Logs with hourly DHU tracking, and introduced an automated defect alert system that notified mechanics whenever a specific defect appeared 3 times in 1 hour.
Impact: Sewing DHU dropped from 24.6% to 3.8% in 6 weeks. Garment throughput time from sewing to packing fell from 48 hours to 6 hours, and customer audit pass rates reached 99.2%.
Commercial Officer Best Practice
Install a dedicated digital or whiteboard Hourly Endline Defect Pareto Chart directly at the end of each sewing line. Every hour, the endline QC updates the top 3 defect categories. If any single defect exceeds 5 occurrences in a single hour, the sewing line supervisor must immediately acknowledge the root cause and sign the CAPA log.
Top Beginner Mistakes to Avoid
- Confusing DHU with Defective Rate (% Defective) by counting defective garments rather than total defect instances.
- Mixing up DHU (a 100% continuous manufacturing metric) with AQL (a statistical random sampling acceptance standard).
- Inspecting only the exterior of the garment and skipping the mandatory inside-out seam and looper audit.
- Allowing defective garments to be repaired by operators without logging the defect in the daily quality register.
- Calculating daily DHU only at the end of the shift, missing the opportunity for real-time hourly root cause intervention.
- Ignoring the Pareto 80/20 rule and attempting to fix all 15 minor defect types at once instead of eliminating the top 3 dominant flaws.
Important Commercial & Trade Terminology (6 Terms)
The standard apparel manufacturing quality metric representing the total number of defects discovered per 100 inspected garments: (Total Defects / Total Inspected) * 100.
💡 Note: Allows total defect count to exceed garment count.The percentage of inspected garments that contain one or more defects: (Defective Units / Total Inspected) * 100.
💡 Note: Always less than or equal to DHU.A standardized, ergonomic physical garment inspection sequence that follows a clockwise loop around the garment to ensure 100% coverage in < 60 seconds.
💡 Note: Standard industry inspection SOP.A continuous tracking register maintained at the end of each sewing line recording hourly inspection counts, specific defect types, and DHU calculations.
💡 Note: Serves as the basis for daily factory quality dashboards.The statistical principle that approximately 80% of all garment quality defects originate from 20% of the sewing operations or root causes.
💡 Note: Focuses engineering resources on the top 3 dominant flaws.The percentage of garments that pass 100% endline inspection on the first attempt without requiring any rework, unpicking, or repair.
💡 Note: Benchmark target is > 95%.Interview Preparation Questions & Answers (4 Questions)
Master these high-frequency interview questions for Commercial Officer, Merchandising, and Export Executive roles.
DHU stands for Defects per Hundred Units. Its formula is: DHU = (Total Number of Defects Found / Total Garments Inspected) * 100. It measures the total defect density across all garments. Defective Percentage (% Defective) is: (Total Defective Garments / Total Garments Inspected) * 100, which measures the proportion of garments requiring repair. For example, if 100 garments are inspected and 5 garments are found defective containing a total of 12 defects (e.g. some garments have 2 or 3 flaws), the DHU is 12.0%, while the Defective Rate is 5.0%.
Frequently Asked Questions (3 FAQs)
Clear, beginner-friendly answers to the most common questions about the Commercial Department.
Key Takeaways & Summary Points
Executive Lesson Summary
Endline Inspection and DHU calculation form the definitive operational quality metric of garment assembly. By executing systematic 7-point clockwise inspections, logging hourly defect tallies, calculating true DHU values, and executing Pareto-driven root cause actions, apparel manufacturers maintain tight process control and guarantee that only first-quality garments enter the finishing and packing departments.
Lesson Downloads & SOP Templates
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