Nylon is a type of synthetic polymer known as polyamide. Nylon and polyamide are essentially the same thing and are used interchangeably in most cases. However, in some technical or scientific discussions, “polyamide” is used as a more generic term to encompass a broader range of polymers within the polyamide family. It can include various types of polyamides, such as nylon 6, nylon 6/6, nylon 12, and so on, each with its own specific properties and characteristics. Therefore, nylon and polyamide refer to the same family of polymers, with nylon being a specific type of polyamide.
Nylon was developed by DuPont in the 1930s. It is a versatile material known for its exceptional strength, durability, and resistance to wear and abrasion. It is a versatile and popular material for plastic injection molding services due to its excellent properties. Nylon is widely used in various industries, including automotive, aerospace, electronics, and consumer goods, for applications such as gears, bearings, electrical connectors, and structural components.
What Are the Properties of Injection Molding Nylon?
Why Is Nylon Good for Injection Moulding？
Nylon exhibits several advantageous properties that make it a suitable material for injection molding applications.
- High tensile strength, comparable to some metals
- Excellent fatigue resistance, ideal for components under cyclic loading, like gears
- Good impact and abrasion resistance
- Low coefficient of friction
- High maximum operating temperature up to 150°C for long-term exposure
- Higher melt temperature and heat resistance when reinforced with glass fibers
- Moisture absorption requires proper drying before molding to prevent defects
- Dimensional stability and low shrinkage rate of 1-2%
What Are the Disadvantages of Nylon？
While nylon offers excellent mechanical properties and chemical resistance, it has drawbacks that need to be addressed through design considerations and precise process control.
- High moisture absorption leading to dimensional issues and defects
- Susceptibility to degradation from strong acids and bases
- Notch sensitivity causes a reduction in impact strength
- UV degradation requires stabilizers for outdoor applications
- Processing challenges like gassing, voids, warpage due to moisture, and shrinkage
- Relatively high material cost compared to some other plastics
Different Types of Nylon
There are several different types of nylon available for injection molding, such as Nylon 6 (PA6), Nylon 66 (PA66), Nylon 11 (PA11), and Nylon 12 (PA12). Each has its own unique characteristics and applications. Here are some common types of nylon used in injection molding:
These are just a few examples of the different types of nylon used in injection molding. The selection of the appropriate nylon type depends on the specific requirements of the application, including mechanical properties, chemical resistance, heat resistance, and cost considerations. It is important to consult with material suppliers or experts to choose the most suitable nylon grade for your injection molding project.
Nylon Material Property
Why Choose Nylon Injection Molding Over Other Processing Methods?
The process of nylon injection molding begins with feeding nylon pellets into the hopper of the injection molding machine. These pellets are heated to a molten state and then injected into a precisely designed mold cavity under high pressure. Once the molten nylon fills the cavity, it is cooled and solidified to form the desired part. After cooling, the mold opens, and the finished component is ejected.
Nylon injection molding offers a unique balance of strength, toughness, and lightweight performance. It provides excellent wear resistance, chemical stability, and heat tolerance, making it reliable even under demanding conditions. In addition, the process allows high design flexibility and efficiency, enabling the production of complex parts at a competitive cost.
Nylon injection-molded parts are commonly found in automotive components such as gears, bearings, and engine covers. In the electronics industry, they are used in connectors, housings, and switch components. Nylon is also applied in industrial machinery, sporting goods, and consumer products.
Nylon Injection Molding Service
Other Processing Methods for Nylon
Nylon Extrusion
In nylon extrusion, the material is first melted in the extruder barrel and then forced through a shaped die. The continuous profile is cooled and solidified using water baths or chill rolls before being cut or wound into the desired length. This method is primarily used to produce rods, tubes, sheets, and filaments, which can serve as structural materials, semi-finished stock for machining, or fibers for textile and industrial applications.
Nylon CNC Machining
In CNC machining, solid nylon blocks or extruded stock shapes are clamped onto a machine and cut into the desired form using computer-controlled tools. The process removes material layer by layer to achieve precise dimensions and complex geometries. This method is commonly used for low-volume parts, prototypes, and components with tight tolerances, such as precision gears, fittings, and custom mechanical parts, where injection molding or extrusion may not be practical.
Nylon CNC Machining Service
Conditions of Nylon Injection Molding Process
The conditions of the nylon plastic injection molding process play a crucial role in achieving successful and high-quality results. Here are some key considerations for the nylon injection molding process:
1. Nylon Injection Molding Temperature
There can be some variation based on grade and reinforcement, the following shows the most standard nylon 6 material temperature during injection molding.
- 230°C – 280°C (446°F – 536°F) for unfilled/unreinforced grades
- 250°C – 300°C (482°F – 572°F) for glass fiber reinforced grades
For other nylon types like Nylon 66 (PA66), the melt temperature range is generally similar to Nylon 6.
Some key points regarding nylon molding temperatures:
- The melting point of most nylons is around 220°C – 225°C, so the molding temperature needs to be higher than this for proper melting and flow.
- Heating nylon above 300°C can cause degradation, discoloration and viscosity reduction.
- The exact molding temperature is optimized based on the nylon grade, filler content, flow length, part thickness and other processing conditions.
2. Injection Pressure
Nylon requires higher injection pressures compared to some other plastics due to its higher viscosity. Adequate injection pressure ensures that the molten nylon fills the mold cavity completely and achieves the desired part shape and dimensions. The injection pressure typically ranges from 8000 psi to 20000 psi (55 MPa to 138 MPa).
3. Injection Speed
Controlling the injection speed helps in achieving uniform filling and avoiding issues like flow marks or material degradation. The injection speed depends on factors such as part complexity, wall thickness, and the desired surface finish. It is crucial to optimize the injection speed for each specific nylon material and part design.
4. Cooling Time
Proper cooling is necessary to solidify the molten nylon inside the mold and ensure dimensional stability. Nylon has a relatively slow cooling rate, and the cooling time should be sufficient to prevent warping or shrinkage. The cooling time can be influenced by factors like part thickness, mold design, and cooling system efficiency.
5. Mold Design
The mold design for nylon injection molding should consider factors such as gate location, part ejection, venting, and wall thickness. Gate design should facilitate smooth material flow and prevent air entrapment. Venting is crucial to release trapped air during the injection process. Proper wall thickness helps maintain part strength and dimensional stability.
6. Drying
Nylon is hygroscopic, meaning it absorbs moisture from the environment. Therefore, it is important to dry nylon pellets before the injection molding process to eliminate moisture content. Moisture can cause surface defects or affect the material properties.
By carefully controlling these process conditions and parameters, it is possible to achieve high-quality nylon injection molded parts with excellent mechanical properties, dimensional accuracy, and surface finish. It is advisable to consult material suppliers and follow their specific recommendations for the particular grade of nylon being used.
Nylon vs ABS Injection Molding
Nylon and ABS are two common injection molding materials. They have some similarities with the materials of injection molding. Both of them can be modified to enhance specific properties. They can also both be molded into complex shapes and have good dimensional stability.
However, nylon and ABS injection molding also have some differences. Such as below:
Material Properties
- Nylon: Nylon is a polyamide material that offers excellent chemical resistance, low friction, and good fatigue resistance. It has high tensile strength, stiffness, and impact strength.
- ABS: ABS (acrylonitrile butadiene styrene) is a thermoplastic polymer that provides good impact resistance, moderate flexibility, and easy processability. It has high impact strength and good scratch resistance.
Mechanical Properties
- Nylon: Nylon has excellent toughness, high tensile strength, and good abrasion resistance. It is known for its fatigue resistance and can withstand repetitive stress.
- ABS: ABS exhibits high impact strength and moderate flexibility. It offers good tensile strength and toughness, making it suitable for applications that require impact resistance.
Chemical Resistance
- Nylon: Nylon has excellent toughness, high tensile strength, and good abrasion resistance. It is known for its fatigue resistance and can withstand repetitive stress.
- ABS: ABS exhibits high impact strength and moderate flexibility. It offers good tensile strength and toughness, making it suitable for applications that require impact resistance.
Temperature Resistance
- Nylon: Nylon has a higher melting point and can withstand higher temperatures compared to ABS. It offers good thermal stability and retains its properties at elevated temperatures.
- ABS: ABS has a lower melting point and is not as heat-resistant as nylon. It may deform or lose its properties at high temperatures.
Surface Finish
- Nylon: Nylon injection-molded parts tend to have a slightly textured surface finish.
- ABS: ABS injection-molded parts can achieve a smooth and glossy surface finish.
Applications:
- Nylon: Nylon is commonly used in automotive parts, electrical components, industrial equipment, and consumer goods that require strength, chemical resistance, and low friction.
- ABS: ABS finds applications in industries such as electronics, appliances, toys, and consumer products that require impact resistance, dimensional stability, and ease of processing.
Applications of Nylon Injection Molding
Nylon combines strength, toughness, and chemical resistance, which makes it highly suitable across multiple industries. Below are key sectors where its properties directly support specific applications:
Automotive Components
With high strength, impact resistance, and heat resistance, nylon is ideal for demanding automotive environments. It is widely used in engine covers, intake manifolds, fuel system components, interior trim, and structural parts.
Electrical and Electronic Enclosures
Nylon provides excellent electrical insulation, dimensional stability, and durability, making it suitable for enclosures, housings, and connectors in electrical and electronic devices.
Consumer Goods
Thanks to its toughness, wear resistance, and ability to be molded into complex shapes, nylon is commonly used in tools, appliances, toys, sports equipment, and household products.
Industrial Components
Its low friction, high wear resistance, and resistance to chemicals enable nylon to perform well in gears, bearings, rollers, conveyor system parts, and machine components.
Medical Devices and Equipment
Nylon offers biocompatibility, sterilizability, and chemical resistance, which makes it suitable for surgical instruments, disposable devices, connectors, and equipment housings.
Packaging Components
With durability, chemical resistance, and precision molding capability, nylon is often used in closures, caps, and containers for reliable packaging solutions.
Aerospace Applications
The lightweight nature, strength, and resistance to vibration and chemicals make nylon well-suited for clips, fasteners, brackets, and interior aerospace parts.
Conclusion
Nylon injection molding combines strength, heat resistance, and durability, making it suitable for a wide range of industries and applications. At a custom plastic company, we specialize in nylon injection molding with advanced equipment and proven expertise. From nylon 6 to nylon 66, we deliver precision-molded parts that meet demanding requirements. Contact us today to discuss your project and benefit from our professional molding solutions.
