Integrated Quality Control System

Our quality control system is integrated throughout the entire production process, covering raw material inspection, in-process monitoring, and final product testing.

Each production stage is supported by standardized operating procedures and precise parameter control to ensure stable fibre performance and consistent batch quality.

By combining advanced manufacturing equipment with systematic inspection protocols, we maintain strict control over key performance indicators such as linear density, tensile strength, elongation, moisture content, and fibre uniformity.

This structured quality management approach enables us to deliver reliable fibre solutions for spinning, nonwoven, and filling applications.

quenching machine of fibre production line of dongjindu tianjin export and import co., ltd

PSF Production Process

1. Raw Material Preparation

PET chips are inspected for quality and moisture content.

Chips are dried in controlled drying systems to ensure they are suitable for extrusion.

Quality focus: moisture control, impurity removal, batch traceability.

2. Melting & Extrusion (Front-End Process)

Dried PET chips are melted in extruders under controlled temperature.

The melt is filtered to remove contaminants.

Melt is extruded through spinning beams to form continuous filaments.

Filaments are cooled (quenching) and coated with spin finish to ensure smooth processing.

Quality focus: melt uniformity, filaments without breaks or defects, consistent diameter.

3. Filament Drawing & Initial Collection

Filaments are drawn through rollers to achieve uniform strength and elongation.

Continuous filaments are gathered into tows or cans for back-end processing.

Quality focus: uniform denier, proper lubrication, controlled elongation.

4. Back-End Drawing & Crimping

Tows are threaded through guide frames and multi-roll drawing units.

Tows pass through water baths, oil baths, and steam-heated rollers for controlled drawing.

Filaments are crimped to add bulk and resilience.

Superheated steam may be applied to stabilize crimp and fibre dimensions.

Quality focus: consistent crimp, proper fibre strength, uniformity across the tow.

5. Relaxation & Heat Setting

Crimped tows are heat-set and relaxed to stabilize fibre dimensions.

Tension control systems ensure fibres remain uniform and do not stretch.

Quality focus: dimensional stability, uniform bulk, and consistent fibre performance.

6. Cutting & Packing

Continuous tows are cut into staple fibres of the desired length (e.g., 32mm–64mm).

Finished fibres undergo final inspection for denier, crimp, and other quality parameters.

Fibres are packed under controlled conditions to preserve quality during storage and shipment.

Quality focus: correct cut length, batch consistency, contamination-free packing.

Quality Highlights

✅ Moisture control at raw material stage

✅ Filament uniformity

✅ Crimp consistency

✅ Batch traceability

Lubricating Softening

Cutting

Disc

Quenching Machine

relax heat setting machine for polyester staple fibre production line

Relax Heating Setting Machine

Spinneret

Winding

Machine

Quality Inspection & Testing

1️⃣ Short Intro Line

Every batch of fibre is tested under strict quality standards to ensure consistent performance, stability, and reliability.

2️⃣ Present Tests as a Clear List

Key Quality Inspection Items

Fineness (Denier) Control — Ensures accurate fibre thickness

Cut Length Consistency — Maintains uniform processing performance

Tensile Strength Testing — Verifies durability and mechanical stability

Crimp & Bulk Performance — Ensures loft and resilience

Moisture Content Testing — Controls storage and processing stability

Oil Finish & Smoothness — Ensures good carding and bonding behavior

Color & Shade Consistency — Ensures uniform appearance

Impurity & Contamination Check — Guarantees clean fibre quality

3️⃣ Group Tests into Categories

Raw Material Inspection

Incoming PET quality check

Material cleanliness & consistency

In-Process Quality Control

Denier monitoring

Cut length control

Crimp and fibre uniformity checks

Final Product Testing

Strength & elongation

Moisture & oil content

Appearance & packaging inspection

Certifications & Standards

OEKO-TEX 100

SGS-FR

SGS

GRS

intertek

Quality Commitment

At Dongjindu Fibre, we are dedicated to delivering consistent, reliable, and high-quality polyester staple fibre for our customers worldwide.

We follow strict quality standards in every step of our production, from raw materials to final packaging, ensuring that every batch meets our specifications and your expectations.

Our commitment to quality is supported by:

Continuous process improvement

Strict adherence to international standards

Sustainable and responsible production practices

Long-term partnerships built on trust and reliability

We promise that every product you receive from Dongjindu Fibre reflects our dedication to performance, consistency, and environmental responsibility.

Our responsibility

We are committed to maintaining international standards in every aspect of our operations, ensuring quality, safety, and sustainability throughout our production process.