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Knitting Machines Explained: How Polyester Knitted Fabric Is Made
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.
How to Choose Fabric for Sports Shorts and Gym Shorts: A Complete Guide
Choosing the right fabric is one of the most important decisions when producing sports shorts and gym shorts. The fabric directly affects comfort, stretch, breathability, durability, moisture management, appearance, and overall garment performance.
For clothing brands, sportswear manufacturers, and bulk buyers, selecting the correct sports shorts fabric helps create garments that perform well during workouts while maintaining their shape and appearance after repeated use.
What Makes a Good Sports Shorts Fabric?
Sports shorts require a combination of comfort, flexibility, durability, and moisture management. The ideal fabric should allow the wearer to move freely without feeling heavy or restrictive.
Key properties to consider include:
Stretch and recovery
Moisture-wicking performance
Breathability
Lightweight construction
Quick-drying ability
Durability
Soft hand feel
Shape retention
Colour fastness
Resistance to repeated washing
The best choice depends on the type of sports shorts, intended activity, price range, and target customer.
1. Polyester Fabric for Sports Shorts
Polyester is one of the most widely used fibres for sportswear. It offers good durability, lightweight construction, quick drying, and easy-care properties.
Polyester sports fabrics are suitable for:
Gym shorts
Running shorts
Training shorts
Football shorts
Cricket shorts
Sports uniforms
Athletic wear
Different polyester constructions can provide different levels of stretch, texture, breathability, and performance.
2. Polyester Lycra for Stretch Sports Shorts
For gym and training shorts where flexibility is important, polyester blended with Lycra or elastane can be an excellent option.
The added stretch allows the garment to move with the body while providing better fit and comfort.
It is particularly useful for:
Gym workouts
Fitness training
Functional training
Running
Training shorts
Performance activewear
Stretch recovery is especially important because the fabric should return to its original shape after movement.
3. Mesh Fabric for Breathable Sports Shorts
Mesh fabrics are designed to improve airflow and can be useful for sports activities where ventilation is important.
Mesh is commonly used for:
Football shorts
Basketball shorts
Running shorts
Training shorts
Sports uniforms
Gymwear
The open or engineered construction can improve air circulation and help create a lighter-feeling garment.
4. Interlock and Knit Fabrics
Interlock and other knitted fabrics can provide a smooth surface, comfortable hand feel, and good flexibility.
They can be suitable for casual sports shorts, training garments, and athleisure products where comfort and appearance are equally important.
When selecting a knitted fabric, check its GSM, stretch, recovery, surface texture, and dimensional stability.
5. Consider GSM Carefully
GSM means grams per square metre and indicates the approximate weight of the fabric.
For sports shorts, fabric weight should match the intended use.
Lightweight fabrics can be suitable for running and high-intensity activities where ventilation and low garment weight are important.
Medium-weight fabrics can provide a balance between durability, coverage, comfort, and structure.
However, GSM alone does not determine fabric quality. Fibre composition, construction, finishing, stretch, and fabric performance also matter.
6. Check Stretch and Recovery
Sports shorts need to accommodate movement such as running, squatting, stretching, jumping, and training.
A fabric with suitable mechanical or elastane-based stretch can improve freedom of movement.
Recovery is equally important. After stretching, the fabric should return close to its original dimensions rather than becoming loose or baggy.
For performance sportswear, always test:
Stretch → Movement → Recovery → Repeat
This gives a better indication of how the fabric will perform in an actual garment.
7. Moisture Management and Quick Drying
During exercise, the garment comes into contact with sweat and moisture.
A suitable sports fabric should help manage moisture and dry efficiently.
Quick-drying polyester fabrics are popular for activewear because they can provide practical performance for workouts, outdoor sports, and training.
For premium sportswear, evaluate the actual fabric construction and finishing rather than choosing a fabric based only on fibre name.
8. Fabric Breathability
Breathability becomes especially important for gym shorts, running shorts, and high-intensity sportswear.
Fabrics with suitable construction can allow better air movement and reduce the uncomfortable feeling of excessive heat.
For highly active garments, consider:
Fabric construction
Fabric weight
Mesh panels
Surface structure
Moisture management
Garment design
Fabric performance and garment construction should work together.
9. Choose Fabric According to the End Use
Different sports shorts require different fabric characteristics.
Application
Important Fabric Properties
Running Shorts
Lightweight, breathable, quick drying
Gym Shorts
Stretch, comfort, durability
Football Shorts
Lightweight, durable, moisture management
Basketball Shorts
Breathability, flexibility, durability
Training Shorts
Stretch, recovery, comfort
Casual Sports Shorts
Softness, appearance, durability
Athleisure Shorts
Comfort, appearance, stretch
There is no single fabric that is perfect for every sports-short application.
10. Test the Fabric Before Bulk Production
Before purchasing large quantities, always test the fabric sample.
Check:
GSM
DIA
Width
Stretch
Recovery
Shrinkage
Colour fastness
Pilling resistance
Surface appearance
Washing performance
Sewing behaviour
A small fabric test can help prevent expensive problems during bulk garment production.
How to Select the Right Sports Shorts Fabric
A simple selection process is:
Step 1: Identify the end use.
Step 2: Decide the required level of stretch.
Step 3: Choose the required fabric weight.
Step 4: Evaluate breathability and moisture management.
Step 5: Check stretch recovery.
Step 6: Test shrinkage and colour fastness.
Step 7: Compare fabric cost with the target garment price.
Step 8: Make a sample garment before bulk production.
This approach helps clothing brands choose fabric based on performance requirements rather than price alone.
Common Mistakes When Buying Sports Shorts Fabric
Choosing Only by Price
The cheapest fabric may not provide the required durability or performance.
Ignoring Stretch Recovery
A fabric may initially feel stretchy but lose its shape after repeated movement.
Selecting the Wrong GSM
An unsuitable fabric weight can make the garment feel too heavy, too thin, or unsuitable for the intended activity.
Skipping Fabric Testing
Bulk purchasing without testing can lead to problems with shrinkage, colour, stretch, or finishing.
Not Considering the Garment Design
Fabric selection should match the pattern, fit, pockets, waistband, stitching, and intended movement of the shorts.
Final Thoughts
Choosing fabric for sports shorts requires more than selecting a material based on appearance or price. Stretch, recovery, GSM, breathability, moisture management, durability, and comfort should all be considered before bulk production.
For gymwear, running shorts, training shorts, and other activewear, polyester, polyester-Lycra, mesh, and knitted performance fabrics can offer different advantages depending on the application.
For clothing brands and garment manufacturers, the best approach is to test the fabric, develop a sample, evaluate its performance, and then proceed with bulk production.
The right fabric helps create sports shorts that are comfortable, functional, durable, and suitable for everyday performance.
Single Jersey vs Piqué vs Interlock vs Mesh: A Simple Comparison Guide
Compare Single Jersey, Piqué, Interlock and Mesh fabrics by construction, feel, GSM, breathability, stretch and common applications to choose the right fabric for your garment.