Choosing the wrong material can affect wear resistance, dimensional stability, machining cost, and product lifetime. Understanding the relationship between polyamide and nylon helps you select the correct material for your specific applications.
This article will help you better understand polyamide and nylon, their applications, and the differences between them.
What Is Polyamide Material?
Definition of Polyamide
Polyamide (PA) is a high-molecular-weight polymer with a large number of amide bonds in its molecular chain. It can be either natural or synthetic. Polyamide is not a single material but, in fact, a family of materials. It includes Nylon 6, Nylon 66, Nylon 11, Nylon 12, PA46, PA610, PA612, PA6T, PA9T, and aromatic Polyamide (Aramid).
Common Types of Polyamide
- PA6
This is the most common polyamide and is widely used for gears, bearings, and enclosures. Normally, PA6 is the most cost-effective material for your product.
- PA66
If you are looking for a higher strength, higher heat resistance, and more wear-resistant material, PA66 is the best choice for your applications, such as industrial equipment, automotive parts, and connectors.
- PA11
It is a bio-based material and is widely used in the medical industry.
- PA12
If you want to use SLS 3D printing for prototyping or mass production, this is the best material to be considered.
- PA46
For its high heat resistance, it is usually used for gears, chain tensioners, and electrical connectors.
- PA6T / PA9T
As a general high-temperature nylon, with high rigidity and good cost-effectiveness, they are suitable for high-temperature connectors, LED housings, and automotive electronics.
- Aramid
These are high-performance fibers and cannot be injection-molded alone. They are used to fill modified PA6T/PA9T or for fabric protection and composite material reinforcement.
Here is the chart below for your reference to compare the common polyamide materials.
| Type | Strength | Moisture Absorption | Heat Resistance | Typical Uses |
| PA6 | High | High | Medium | Gears, Bearings |
| PA66 | Higher | Medium | High | Automotive |
| PA12 | Medium | Very Low | Medium | 3D Printing |
| PA11 | Medium | Low | Medium | Tubing |
| PA46 | Very High | Medium | Very High | Engine Parts |
How to Identify Polyamide
You can quickly identify polyamide materials through the following seven simple methods.
- Material Marking
You can check the material labels on the product body, bottom, and label. For genuine products, the material names such as polyamide, nylon, PA, etc., will be clearly printed. This is the most intuitive and easiest way to make a basic identification.
- Resin Identification Code
You can check the plastic recycling triangle logo on the surface of your product to see if it has a specific code. Most are marked with the number 7, and some products will be directly labeled PA, PA6, or PA66.
Once you see such a label, you can preliminarily determine that it is polyamide.
- Appearance
The overall texture of polyamide is smooth and warm. The surface is in a matte or semi-matte state, with no strong reflection. And the touch is delicate and tough.
The common base color is milky white or slightly yellowish. You can make a judgment by directly observing the appearance of the product or component.
- Density
The density of polyamide is slightly higher than that of water. It feels heavy and not light and airy. Compared with PE and PP plastics, it has more weight.
Under the same volume, its weight is significantly higher than that of ordinary general-purpose plastics. Judging the density through the feel and by immersing in water is also a very convenient method for you.
- Water Absorption Test
You can conduct a simple water immersion test to distinguish. Polyamide has a stronger water absorption capacity.
After soaking the sample in water for several hours, you will notice a significant increase in weight and a slight softening of the material, as well as a slight expansion in size. This is the core characteristic that distinguishes it from other plastics.
- Burn Test
When polyamide burns, the flame is gentle. After removing it from the fire, it extinguishes slowly. There is no pungent smoke during the burning process. It emits a burnt hair or burnt wool-like odor. The burned residue is crispy and can be crushed after cooling.
- FTIR Analysis
If you have the equipment to conduct precise FTIR testing, the polyamide will exhibit characteristic spectral peaks corresponding to its specific amide bonds.
What is Nylon Material?
Definition of Nylon
Nylon was first developed by DuPont in the 1930s and became the world’s first fully synthetic engineering polymer. Today, “nylon” commonly refers to synthetic aliphatic polyamides including PA6, PA66, PA11, and PA12.
Common Types of Nylon
Polyamide 6 (PA6): Good toughness, lower price.
Polyamide 66 (PA66): Usually has higher strength and heat resistance than PA6.
Polyamide 11&12 (PA11&PA12): Low water absorption rate, often used in high-end industrial fields.
How to Identify Nylon
Since nylon is a type of polyamide, the same identification methods apply.
If you need to distinguish PA6 from PA66 or verify a material specification, FTIR spectroscopy and DSC analysis are the most reliable laboratory methods.
What Are the Differences Between Polyamides and Nylons?
All Nylon is Polyamide. However, not all Polyamide is Nylon. Nylon is a type of polyamide. Polyamide is the broader category of polymers containing amide bonds, while nylon refers mainly to synthetic aliphatic polyamides such as PA6, PA66, PA11, and PA12.
However, aromatic polyamides such as aramid are not classified as nylon.
There are several main differences between them. See the following for your reference.
Chemical Structure
Nylon (aliphatic polyamide PA6/PA66/PA11/PA12): It is formed by polymerizing fatty monomers, with molecular chains lacking aromatic rings. It has a moderate melting point and can be injection molded or CNC machined. It is the mainstream material for mechanical parts.
Aromatic polyamide (aramid): It contains benzene ring structures and is a high-temperature-resistant, ultra-high-strength fiber. However, it does not belong to nylon and cannot be molded alone. It is only used as a filler or protective fabric.
Properties
Polyamide
It contains amide bonds, has good self-lubrication, oil resistance, and organic solvent resistance. And all have water absorption properties.
Aramid has high temperature resistance and ultra-high tensile strength, but lacks melt flowability and cannot be machined.
Different types of nylon can be molded by melting and can be CNC machined, and the melting point varies with the brand.
Nylon (PA6/PA66/PA11/PA12)
Mechanical properties: Excellent toughness, low friction coefficient, wear-resistant, and self-lubricating, suitable for motion friction parts.
Thermal properties: It has a fixed melting temperature, and you can precisely distinguish them.
Weaknesses: The size slightly expands after absorbing water. When designing precise parts drawings, you need to reserve the moisture tolerance.
Applications
Polyamides
This is applicable when you are planning the full-category materials and compiling the Bill of Materials (BOM), covering all polyamide-based high-molecular materials.
Aliphatic nylon (PA6/PA66/PA11/PA12/PA46/PA6T/PA9T): automotive structural components, industrial transmission gears, connectors, 3D printing blanks, medical tubing, high-temperature-resistant engine parts, and CNC wear-resistant fixtures.
Aramid Aramid: high-strength protective fabrics, composite material filler, and modified materials, special fibers, not used for conventional plastic parts, machined by conventional machinery.
Nylon
This is frequently used when you are drawing mechanical processing drawings and purchasing plastic blanks, only applicable to aliphatic polyamides:
General wear-resistant transmission components, bearing bushings, electronic insulation brackets, textile fabrics, non-standard workpiece sliders, and various injection molded housings.
They are suitable for CNC turning, milling parts, and injection molding.
Comparison Table
| Feature | Polyamide | Nylon |
| Definition | A family of polymers containing amide bonds | A type of synthetic polyamide |
| Category | Broader material group | Subgroup of polyamide |
| Examples | Nylon, Aramid | PA6, PA66, PA11, PA12 |
| Applications | Engineering plastics, fibers, composites | Mechanical parts, textiles |
Which Should You Specify: Polyamide or Nylon?
When should you specify polyamide?
When you are only referring to this type of material in a general sense, it is more accurate to use polyamide. Polyamide is a general name that covers many different materials.
When should you specify nylon?
When you are referring to the actual engineering plastics used, nylon is usually the choice. It is a very common material for CNC machining.
When should you specify a detailed type of Nylon?
If you are in a product design, procurement, processing, or production stage, merely writing “Nylon” or “Polyamide” is not precise enough. It is better to directly indicate the specific brand name, etc. PA6…
FAQ
Are Polyamides Breathable?
Most Polyamides are not breathable, but some nylon fibers used in textiles can enhance their moisture absorption and breathability after undergoing special design.
What Is the Difference Between PA6 and PA66?
PA6 has better fluidity and toughness, and stronger processing performance; PA66 has higher strength, heat resistance, and rigidity, and is suitable for mechanical parts with higher requirements.
What Are Common CNC-Machined Nylon Parts?
Yes, nylon is widely used in gears, bushings, bearings, rollers, electrical insulators, and fixtures.
Can Polyamide and Nylon Be CNC Machined?
Yes, most polyamides can be machined, and nylon is a very common CNC machining material. Due to their excellent wear resistance, low friction coefficient, and good mechanical strength, nylon materials are widely used for precision mechanical components.
What Does PA Mean in Plastic Materials?
PA means Polyamide. In engineering plastics, PA usually refers to nylon materials such as PA6, PA66, and PA12.
Final Thoughts
Nylon is one of the most common materials we use in CNC machining. If you are looking for some high-strength materials, it will be a very suitable choice. Contact us Yecheng for further information.
Send us drawings, and we will provide DFM feedback and quotations in 2 hours.
