OEM Knitwear Quality Assurance & Inline Production Control (Factory-Level System Guide)

Why Inline Quality Control Is Critical in OEM Knitwear

Traditional end-line QC catches defects after they happen.
Inline QC prevents defects from happening at all.

Inline QA affects:

• measurement stability

• panel symmetry

• color consistency

• seam strength

• yarn lot uniformity

• shrinkage stability

• surface smoothness

• tension calibration

• overall production efficiency

• reduction of rework and wastage

Inline QC ensures that the final sweater meets:

• PPS (pre-production sample) standards

• lab-approved color

• approved shrinkage tolerances

• brand fit specifications

• export quality requirements

OEM factories use inline QA to guarantee consistent production across multiple orders and seasons.

OEM QA Workflow Overview

Factory QA involves 7 checkpoints:

1. Yarn Lot Verification

2. Knitting Tension Monitoring

3. Panel Inspection & Measurement

4. Linking & Seaming QC

5. Finishing QC (post-wash/post-steam)

6. Inline Measurement Calibration

7. Final AQL Inspection (Pre-Shipment)

Each stage uses different tools, technicians, and procedures tailored to fiber types and garment categories.

Yarn Lot Quality Control

Yarn issues lead to all downstream defects, so QA begins here.

Yarn Lot Testing Includes:

• yarn evenness test

• twist level check

• tensile strength evaluation

• color lab dip verification

• moisture regain test

• cone weight check

• oil content calibration (especially for wool/acrylic blends)

If yarn lots vary, the following issues occur:

• panel width inconsistency

• color shade mismatch

• uneven shrinkage

• pilling problems

• linking failure

• machine yarn breakage

Inline QC ensures only stable yarn lots enter production.

Knitting Stage QA (Inline Panel Control)

This is the most important structural QA stage.

Panel Inspection Items

• width accuracy

• length accuracy

• needle line straightness

• panel symmetry

• stitch density uniformity

• gauge consistency

• hole detection

• yarn break identification

• tension line marks

Panel Control Tools

• digital width measurement devices

• tension control systems

• Shima/ Stoll software monitoring

• in-machine needle line cameras

• laser-guided panel measurement

Factories must maintain ±0.5–1.0 cm tolerance before finishing.

Keywords:

• tension-controlled knitwear factory

Stitch Density Monitoring

Stitch density determines:

• shrinkage

• drape

• stretch

• final measurements

Factories check stitch density:

• every 30 panels

• on each knitting machine change

• when yarn lot changes

• when the gauge machine is adjusted

Density too tight → shrinkage increases
Density too loose → garment grows after finishing

Inline correction prevents bulk production deviation.

Inline Linking & Seam Inspection

Linking is checked while in progress.

QC Checks During Linking

• loop alignment

• seam elasticity

• neckline symmetry

• armhole curve accuracy

• seam bulk control

• shoulder slope accuracy

• rib joining consistency

Mistakes caught early avoid hundreds of defective garments.

Tools Used

• loop inspection magnifier

• seam tension gauge

• linking needle alignment tools

Keywords:

• linking knitwear manufacturer

Finishing QA (After Washing & Steaming)

After finishing, garments change dramatically—so QA must verify post-wash results.

Key Finishing QA Checks

• final measurements vs PPS

• shrinkage rate

• colorfastness

• surface appearance

• pilling grade

• neckline recovery

• drape quality

• rib elasticity

• weight change

Finishing QC is done on:

• first 5 pieces of each batch

• every color

• every size

• every shift change

Keywords:

• pre-shrunk knitwear manufacturer

• colorfast sweater supplier

Inline Measurement Calibration

Factories calculate measurement tolerance using:

• PPS spec

• shrinkage rate

• finishing machine conditions

• rib tension

• yarn behavior

Inline Measurement Control Includes:

• width & length template

• shoulder slope block

• neckline curve template

• sleeve length board

• rib height alignment tools

A garment must match measurement tolerance ±1–1.5 cm depending on category.

Inline Surface Quality Inspection

Surface inspection identifies:

• pilling

• hairiness

• oil stains

• color streaks

• uneven finishing

• snagged yarn

• loop pull

• shade variation

These issues must be corrected before bulk washing continues.

Tools Used

• fabric lightbox

• combing test tools

• handheld surface scanner

Shrinkage Monitoring Across Bulk Production

Shrinkage is recalibrated:

• at start of bulk

• after yarn lot change

• after machine maintenance

• when finishing recipe changes

Factories use:

• mini wash tests

• tumble simulation tests

• steam shrinkage simulation

Bad shrinkage = total production failure
Inline monitoring prevents this.

Keywords:

• knitwear shrinkage control service

Panel Matching & Symmetry Control

Panels are checked for symmetry:

• left vs right sleeves

• body panel matching

• neckline curve alignment

• armhole balance

• side seam alignment

Panel mismatch causes:

• twisting

• misaligned seams

• uneven shoulders

OEM factories maintain “paired panel control” to avoid asymmetry.

Seam Strength Testing

Sweaters must withstand:

• stretching

• repeated washing

• consumer wear

Factories test:

• bursting strength (ISO)

• seam slippage

• tensile strength of linked areas

• needle damage checks

These tests are critical for corporate & school uniform knitwear.

Keywords:

• bulk production quality management

Inline Pilling Prevention

Pilling is monitored throughout production—not just after finishing.

Inline Anti-Pill Control Includes:

• fiber selection QA

• stitch density calibration

• finishing chemistry adjustments

• anti-pill softener application

• controlled agitation during washing

• rib tension stability

Factories perform “quick pill tests” every batch using a mini pilling machine.

Color Shade Control During Bulk Production

Shade differences often occur when:

• new yarn lots arrive

• machines operate at different temperatures

• finishing for different batches varies

• drying conditions change

Shade control involves:

• shade bands

• inline shade comparison

• controlled drying conditions

• yarn lot separation

Shade lot management ensures consistency across thousands of garments.

AQL Levels for Knitwear

Before shipment, AQL testing is applied.

Typical AQL standards:

• AQL 2.5 for general knitwear

• AQL 1.5 for luxury brands

• AQL 4.0 for basic corporate orders

AQL testing checks:

• measurements

• seams

• appearance

• color consistency

• accessories

• labels and hangtags

• packaging

MES (Manufacturing Execution System) in QA

Modern factories use MES for:

• tracking raw materials

• real-time QC data

• operator accountability

• defect logging

• panel traceability

• linking station logs

• finishing schedule

• order progress tracking

MES ensures transparency and repeatability.

Keywords:

• knitwear production workflow

Pre-Shipment Final QC

Performed before goods are packed.

Checklist includes:

• measurement check (full size set)

• color verification

• surface inspection

• pilling grade

• seam inspection

• packaging

• carton weight & sealing

• barcode accuracy

• shipping labels

Keywords:

• sweater QC inspection checklist

Quality Assurance for Export Markets

Different markets require different compliance standards.

Required Tests:

• REACH compliance (EU)

• AATCC colorfastness (US)

• Oeko-Tex safety certification

• CPSIA requirements for children’s wear

• GB standards for China

Export QC Includes:

• humidity control

• odor-free finishing

• correct folding method

• carton compression test

How OEM Factories Reduce Defects Before They Happen

Factories use predictive QA:

Predictive Controls Include:

• yarn lot analysis

• machine condition logs

• operator skill matching

• heat & humidity tracking

• shrinkage projection

• stitch density simulation

• MES-based risk warnings

This shifts QA from reaction to prevention.