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Training Manual — Section 5

Defects & Quality Engineering

The complete defect reference — stitch, seam, fabric, measurement, finishing, and packing defects, plus the quality engineering tools used to analyze and prevent them.

Contents

01Stitch Defects02Seam Defects03Fabric Defects04Measurement Defects05Finishing Defects06Packing Defects07Quality Engineering Tools08Classification & Disposition09Root Cause & Prevention10Repair Quality Control
Stitch Defects
Section 01

Stitch Defects

Defects related to stitch formation, tension, and thread integrity.

Major Stitch Defects

  • Skipped stitches
  • Loose stitches
  • Tight stitches
  • Broken stitches
  • Uneven stitch density
  • Thread pulling
  • Thread breakage

Causes

  • Wrong tension
  • Needle damage
  • Incorrect thread path
  • Poor machine maintenance

Quality Checkpoints

  • Stitch density: 8–12 SPI
  • Balanced tension
  • No skipped stitches
  • No thread breakage
Seam Defects
Section 02

Seam Defects

Defects related to seam formation, alignment, and strength.

Major Seam Defects

  • Puckering
  • Open seam
  • Uneven seam allowance
  • Twisted seam
  • Weak seam strength
  • Raw edges exposed

Causes

  • Wrong feed setting
  • Incorrect seam allowance
  • Poor fabric handling
  • Wrong needle size

Quality Checkpoints

  • Seam strength test
  • Seam alignment
  • No puckering
  • Correct seam allowance
Fabric Defects
Section 03

Fabric Defects

Defects originating in the fabric itself — yarn, weaving, and dyeing faults.

Major Fabric Defects

  • Slubs
  • Knots
  • Holes
  • Barre
  • Contamination
  • Color variation
  • Weaving faults

Causes

  • Yarn inconsistency
  • Machine faults
  • Dyeing issues
  • Poor finishing

Quality Checkpoints

  • 4-point system
  • Roll inspection
  • Defect mapping
Measurement Defects
Section 04

Measurement Defects

Defects in garment dimensions, grading, and pattern alignment.

Major Measurement Defects

  • Out of tolerance
  • Uneven sleeve length
  • Uneven hem
  • Wrong grading
  • Incorrect pattern alignment

Causes

  • Wrong pattern
  • Poor cutting accuracy
  • Shrinkage not considered
  • Wrong stitching tension

Quality Checkpoints

  • Tolerance control
  • Symmetry check
  • Pattern matching
  • Final measurement audit
Finishing Defects
Section 05

Finishing Defects

Defects introduced during pressing, cleaning, and final presentation.

Major Finishing Defects

  • Stains
  • Dirt marks
  • Pressing shine
  • Wrinkles
  • Poor label attachment
  • Loose threads

Causes

  • Poor handling
  • Wrong pressing temperature
  • Dirty workplace
  • Incorrect label machine setting

Quality Checkpoints

  • Clean appearance
  • Proper pressing
  • No loose threads
  • Label alignment
Packing Defects
Section 06

Packing Defects

Defects in folding, packaging, and final presentation before shipment.

Major Packing Defects

  • Wrong folding
  • Wrong size sticker
  • Wrong polybag
  • Missing barcode
  • Poor presentation

Causes

  • Incorrect SOP
  • Wrong packing line setup
  • Human error

Quality Checkpoints

  • Correct folding
  • Correct stickers
  • Correct polybag size
  • Barcode scan test
Section 07

Quality Engineering Tools

Structured methods convert defect observations into controlled, measurable process improvement.

Analysis Tools

  • Pareto chart prioritizes the vital few defect types
  • Defect maps reveal location and pattern concentration
  • 5 Why traces cause-and-effect beyond the visible symptom
  • Fishbone analysis checks material, machine, method, people, measurement, and environment
  • Control charts distinguish common from special-cause variation
  • FMEA prioritizes prevention using severity, occurrence, and detection risk

Data Discipline

  • Use one controlled defect code and definition library
  • Record operation, location, severity, source, line, machine, and material lot
  • Separate defects from defective garments and rework events
  • Use stable denominators for DHU, defect rate, and first-pass yield
  • Calibrate inspectors with reference samples and correlation audits

Quality Checkpoints

  • Correct sampling and severity
  • Traceable evidence
  • Corrective action verified for effectiveness
Section 08

Classification & Disposition

Severity reflects safety, legal compliance, function, appearance, saleability, and customer expectation—not defect size alone.

Severity Rules

  • Critical: unsafe, illegal, prohibited, or potentially harmful
  • Major: likely to cause rejection, failure, or material loss of usability
  • Minor: departure from standard with limited effect on use or saleability
  • Apply buyer-specific examples and zone rules before generic guidance
  • Count multiple defects according to the governing inspection protocol

Disposition

  • Accept only when the lot meets approved criteria
  • Repair only with an approved method that creates no new risk
  • Reinspect repaired pieces and retain repair traceability
  • Concession requires authorized written approval before shipment
  • Reject, downgrade, or scrap when conformity cannot be restored

Quality Checkpoints

  • No critical defect released
  • Disposition authority defined
  • Repairs reinspected against original specification
Section 09

Root Cause & Prevention

Defect prevention connects occurrence and escape causes to process controls at the earliest responsible operation.

Investigation

  • Contain the suspected time window and preserve samples
  • Recreate the failure under controlled conditions
  • Compare good and bad output, settings, components, and methods
  • Identify occurrence cause and why detection controls failed
  • Confirm the cause by removing or introducing the suspected variable

Prevention Controls

  • Error-proof folders, guides, templates, sensors, and machine programs
  • Approve first piece after every startup, changeover, repair, and material change
  • Define parameter windows and reaction plans
  • Train to standardized work with visual defect boundaries
  • Audit effectiveness and update PFMEA, control plan, and SOP

Quality Checkpoints

  • Cause supported by evidence
  • Action controls the source
  • Recurrence monitored across similar products
Section 10

Repair Quality Control

Repair restores conformity without weakening construction, changing appearance, contaminating the garment, or hiding systemic loss.

Repair Standard

  • Define authorized repairs by defect and product zone
  • Use approved thread, needle, stitch, chemical, pressing, and handling method
  • Remove original defect fully without needle damage, marks, holes, or distortion
  • Maintain bundle, size, shade, and order identity during repair
  • Prohibit cosmetic concealment that does not restore conformity

Verification

  • Independent reinspection after repair
  • Recheck measurement, strength, appearance, and function affected by repair
  • Track repair quantity and repeat repair separately
  • Escalate high repair rate to process containment
  • Return passed pieces through the controlled production flow

Quality Checkpoints

  • Approved repair method
  • Independent verification
  • Repair data feeds root-cause prevention

Continue your training

Explore the fabric knowledge base and the full module library.

Fabric knowledge

Advanced reference

Technical controls & troubleshooting

Defect Taxonomy

  • Code defects by source, location, operation, severity, responsibility, and repairability
  • Critical defects create safety, legal, regulatory, or prohibited-item risk
  • Major defects affect function, saleability, fit, durability, or obvious appearance
  • Minor defects depart from standard without materially affecting use or saleability
  • Use physical defect samples and photographs to align inspectors and operators
  • Review classification against the buyer defect manual before every new program

Analytical Methods

  • Pareto analysis identifies the vital few defect types
  • DHU = total defects ÷ units inspected × 100
  • First-pass yield = accepted without repair ÷ total checked × 100
  • Control charts separate common-cause from special-cause variation
  • Fishbone analysis covers material, machine, method, people, measurement, and environment
  • 8D or CAPA records containment, root cause, permanent correction, and effectiveness

Prevention Controls

  • Verify defect prevention at incoming, first-output, inline, end-line, and final stages
  • Separate critical, major, and minor defects using the approved defect library
  • Use risk-based sampling; increase frequency after a failure or process change
  • Maintain shade, size, lot, roll, and bundle traceability throughout production
  • Quarantine nonconforming output until disposition and corrective action are approved
  • Confirm corrective action effectiveness on consecutive production checks

Troubleshooting

  • Contain affected defect output and identify the last verified-good checkpoint
  • Use 5 Why and fishbone analysis across material, machine, method, people, and environment
  • Compare failed output with the sealed sample, specification, and machine settings
  • Correct the root cause rather than relying on repeated inspection or repair
  • Run a controlled trial, validate results, then release the updated process setting
  • Update SOP, control plan, training record, and preventive-maintenance requirement

Written by Sanjeewa Dehiwalage — www.nosk.life — All rights reserved.

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