Knitted polyester fabric is widely used in T-shirts, sportswear, activewear, jerseys, track pants, casualwear and uniforms. But before polyester becomes a finished fabric, the yarn must pass through a knitting process that determines much of the fabric's appearance, stretch, texture and performance.
Knitting machines play an important role in converting polyester yarn into a continuous fabric structure. Different machines and knitting techniques can create fabrics with different GSM, stretch, surface texture, drape, breathability and appearance.
Understanding how knitting machines work can help garment manufacturers, clothing brands and fabric buyers make better decisions when selecting polyester knitted fabrics.
What Is a Knitting Machine?
A knitting machine is textile equipment that converts yarn into fabric by forming interconnected loops.
Unlike weaving, which creates fabric by crossing yarns in different directions, knitting creates fabric through loops.
This loop structure gives knitted fabrics characteristics such as:
- Flexibility
- Stretch
- Soft hand feel
- Comfortable drape
- Good movement
- Different surface textures
The final characteristics depend on the yarn, machine type, knitting structure and finishing process.
How Is Polyester Knitted Fabric Made?
The basic process can be simplified as:
Polyester Yarn → Knitting Machine → Fabric Formation → Dyeing → Finishing → Inspection → Finished Fabric
Each stage affects the final fabric.
1. Polyester Yarn Selection
The process starts with the right polyester yarn.
Depending on the required fabric, manufacturers may use:
- Spun polyester yarn
- Filament polyester yarn
- Textured polyester yarn
- Different yarn counts and specifications
Yarn selection influences the eventual:
- Hand feel
- Surface appearance
- Drape
- Strength
- Texture
- Fabric weight
The yarn must be suitable for the intended knitting structure and garment application.
2. Yarn Feeding
The selected polyester yarn is supplied to the knitting machine through controlled yarn-feeding systems.
Consistent yarn feeding is important because uneven feeding can affect the appearance and structure of the finished fabric.
During production, manufacturers control factors such as:
- Yarn tension
- Feeding consistency
- Machine speed
- Stitch formation
These settings help maintain uniform fabric construction.
3. Loop Formation
The key function of a knitting machine is to create loops from the yarn.
Needles and other machine components guide the yarn and form interconnected loops.
As the machine continues operating, these loops build into a continuous fabric structure.
The size, arrangement and density of the loops influence characteristics such as:
- Stretch
- Thickness
- GSM
- Surface texture
- Drape
- Breathability
4. Different Knitting Structures
Different knitting structures can produce very different polyester fabrics.
Some common knitted structures include:
Single Jersey
A widely used structure for T-shirts and lightweight apparel.
It can provide:
- Soft hand feel
- Comfortable drape
- Good flexibility
- Lightweight construction
Piqué / Lacosta
Commonly used for polo-style garments.
It can provide:
- Textured surface
- Structured appearance
- Comfortable wear
- Different levels of breathability depending on construction
Interlock
Interlock has a more stable and smooth construction compared with many single-jersey fabrics.
It can be used for:
- T-shirts
- Activewear
- Casualwear
- Premium garments
Rib
Rib structures are commonly used where additional flexibility is required, particularly for:
- Collars
- Cuffs
- Neckbands
- Fitted garments
Mesh
Mesh structures are designed with more open construction to support airflow.
They are widely used in:
- Sportswear
- Jerseys
- Activewear
- Training garments
5. Circular Knitting Machines
Circular knitting machines are widely used to produce knitted fabrics in a continuous tubular form.
The needles are arranged around a cylinder, allowing the machine to create fabric continuously.
Circular knitting machines can be used to produce many types of polyester knitted fabrics.
They are particularly common for:
- T-shirt fabrics
- Sportswear fabrics
- Jersey fabrics
- Polo fabrics
- Activewear
- Casualwear
Different machine settings and knitting structures can produce different fabric characteristics.
6. Flat Knitting Machines
Flat knitting machines produce fabric in a flatter format rather than continuously around a cylinder.
They are commonly associated with products requiring shaped or engineered knitted structures.
Applications can include:
- Sweaters
- Collars
- Cuffs
- Knitted panels
- Shaped components
The appropriate machine depends on the product and construction required.
7. How Machine Settings Affect Fabric
Knitting machines are not simply used to create fabric. Their settings can significantly influence the final result.
Important factors can include:
- Machine gauge
- Stitch length
- Yarn tension
- Machine speed
- Needle configuration
- Fabric take-down
- Knitting structure
Changes in these settings can affect:
- GSM
- Width
- Stretch
- Surface appearance
- Fabric density
- Drape
This is why two polyester fabrics made from similar yarns can still have very different characteristics.
What Is Machine Gauge?
Gauge refers broadly to the fineness or density of the needle arrangement in a knitting machine.
Different gauges are suitable for different types of knitted structures and fabric requirements.
The machine gauge can influence:
- Stitch size
- Fabric fineness
- Surface appearance
- Fabric density
However, gauge alone does not determine the final GSM or quality of the fabric.
What Is Stitch Length?
Stitch length refers to the amount of yarn used to form an individual knitted loop.
Changing stitch length can affect:
- Fabric weight
- Density
- Stretch
- Thickness
- Surface appearance
Manufacturers carefully control stitch length to achieve the required fabric specification.
How Does Knitting Affect GSM?
Knitting construction has a major influence on fabric GSM.
GSM can change depending on:
- Yarn specification
- Stitch length
- Fabric density
- Knitting structure
- Machine settings
- Finishing
Therefore, GSM should be measured on the finished fabric rather than estimated only from the yarn.
How Does Knitting Affect Stretch?
Knitted fabrics naturally have flexibility because of their loop structure.
However, the amount of stretch varies according to:
- Knitting structure
- Yarn characteristics
- Stitch length
- Fabric density
- Elastane content, if used
For example, an open mesh structure may behave differently from a dense interlock fabric.
How Does Knitting Affect Breathability?
The structure of the knitted fabric influences airflow.
Open structures such as certain mesh constructions can allow more air movement, while denser structures can provide greater coverage.
For sportswear, buyers should evaluate the actual fabric for:
- Airflow
- Moisture management
- Comfort
- GSM
- Surface structure
From Knitted Fabric to Finished Garment
After knitting, the fabric may go through additional processing before it becomes suitable for garment production.
A simplified process is:
Polyester Yarn
↓
Knitting Machine
↓
Grey Fabric
↓
Dyeing
↓
Finishing
↓
Quality Inspection
↓
Fabric Roll
↓
Cutting & Stitching
↓
Finished Garment
Each stage can affect the final fabric.
Why Does Finishing Matter?
Knitting creates the basic fabric structure, but finishing can modify its final characteristics.
Finishing can influence:
- Softness
- Smoothness
- Hand feel
- Drape
- Surface appearance
- Dimensional stability
This is why the same polyester yarn and similar knitting structure can produce fabrics with different final feels.
Quality Checks for Knitted Polyester Fabric
After production and finishing, fabric should be inspected before being used for bulk garment production.
Important checks can include:
GSM
Confirm the actual fabric weight.
DIA
Check the usable width of knitted fabric.
Colour
Check shade consistency and colour fastness.
Surface
Look for defects, unevenness or unwanted marks.
Stretch and Recovery
Important for sportswear and fitted garments.
Width Consistency
Check whether the fabric maintains the required width throughout the roll.
Hand Feel
Evaluate softness, smoothness and overall fabric character.
Washing Performance
Where required, test dimensional stability, colour and appearance after washing.
Why Two Knitted Polyester Fabrics Can Feel Different
It is common to find two polyester knitted fabrics that look similar but feel completely different.
This can happen because of differences in:
Yarn + Machine + Knitting Structure + GSM + Finishing
For example:
One fabric may be:
- Lightweight
- Soft
- Fluid
- Highly breathable
Another may be:
- Heavier
- More structured
- Denser
- More stable
Both can still be polyester knitted fabrics.
Choosing the Right Knitted Fabric for Different Garments
| Garment | Important Characteristics |
|---|---|
| T-Shirts | Softness, comfort, drape, breathability |
| Sports Jerseys | Lightweight construction, airflow, moisture management |
| Polo Shirts | Structure, comfort, surface texture |
| Track Pants | Stretch, recovery, drape, durability |
| Activewear | Stretch, recovery, breathability |
| Casualwear | Comfort, hand feel, appearance |
| Uniforms | Durability, comfort, colour consistency |
The ideal knitting structure depends on the specific garment requirements.
What Should Fabric Buyers Ask Suppliers?
Before purchasing knitted polyester fabric, ask for the complete specification.
Important details include:
- Fibre composition
- Yarn type
- Yarn specification
- Knitting structure
- GSM
- DIA
- Colour
- Finish
- Stretch
- Recovery
- Intended application
It is also useful to request a physical fabric sample before placing a large bulk order.
Frequently Asked Questions
What does a knitting machine do?
A knitting machine converts yarn into fabric by forming interconnected loops.
Which knitting machine is used for polyester fabric?
Circular knitting machines are widely used for polyester knitted fabrics, while flat knitting machines are used for specific knitted products and shaped components.
What is circular knitting?
Circular knitting creates fabric continuously using needles arranged around a cylinder.
What is single jersey?
Single jersey is a common knitted structure used for T-shirts and lightweight garments.
Does knitting affect GSM?
Yes. Yarn specification, stitch length, machine settings, density and knitting structure can all affect the final GSM.
Does knitting affect fabric stretch?
Yes. The loop structure of knitted fabric provides flexibility, while the amount of stretch depends on construction, yarn and other factors.
What is machine gauge?
Machine gauge generally describes the fineness or density of the needle arrangement in a knitting machine.
Why do two polyester knitted fabrics feel different?
Differences in yarn, knitting structure, machine settings, GSM and finishing can produce very different fabric characteristics.
Final Thoughts
Knitting machines play a critical role in converting polyester yarn into usable knitted fabric.
The basic process is:
Yarn → Yarn Feeding → Loop Formation → Knitting Structure → Dyeing → Finishing → Inspection
Different knitting machines and settings can create fabrics with different GSM, stretch, texture, breathability, drape and hand feel.
For garment manufacturers and fabric buyers, understanding the knitting process makes it easier to evaluate fabric specifications and choose the right material for the intended garment.
The final quality of knitted polyester fabric depends on the complete combination of:
Yarn + Machine + Knitting Structure + GSM + Finishing
Rather than selecting fabric based only on its name or fibre composition, evaluate the actual fabric sample and its performance before moving into bulk production.
