Brief Introduction of Nylon
What is Nylon?
Nylon, also known as polyamide and abbreviated as PA, is a synthetic fiber, plastic, and polymer. It was invented in 1935 by Wallace Carothers of DuPont, USA. Nylon comes in various types, such as nylon 6, nylon 66, nylon 12, nylon 610, etc., all of which fall under the category of engineering plastics. Due to its structural properties, nylon exhibits superior rigidity, toughness, chemical resistance, and weather resistance compared to general-purpose plastics. As a result, it is commonly used in engineering components, automotive parts, electrical products, office furniture, medical equipment, and other applications.

The main characteristics of nylon are as follows:

Appearance: Nylon is a crystalline polymer, typically displaying an opaque, milky-white appearance. This is due to the arrangement of nylon molecules, which prevent complete light transmission and cause reflection and scattering, resulting in the milky-white appearance.

Moisture absorption and impact resistance: The individual amide groups in nylon readily form hydrogen bonds with water molecules. Even after the molding process, nylon products continue to absorb moisture from the surrounding air, a property known as moisture regain. This moisture absorption contributes to excellent impact resistance in nylon. The presence of water molecules increases the toughness and ductility of nylon, making it more resistant to external forces.

Moisture absorption and impact resistance are just two of the characteristics of nylon, and there are other important properties as well, including high heat resistance, high rigidity, chemical resistance, and abrasion resistance.

Furthermore, to enhance the performance of nylon, additional additives are often incorporated to create nylon composites. For example, the addition of materials like glass fibers, mineral fillers, carbon fibers, etc., can improve the strength and heat resistance of nylon. Glass fiber is a commonly used additive, referred to as "glass-filled nylon" or "nylon + GF" (GF denoting glass fiber). The incorporation of glass fibers significantly improves the strength, heat deflection temperature, and dimensional stability of nylon. The proportions of additives, including glass fiber, can be adjusted according to the specific requirements of the product to achieve optimal performance.

Nylon 6

The name of nylon 6 is derived from the ring-opening polymerization of caprolactam containing six carbon atoms in its chemical structure. Nylon 6 has a density of 1.14(g/cm3) and a melting point of 220°C. In addition to the main properties of nylon: good impact strength, high heat deformation resistance, high rigidity, high chemical resistance and high wear resistance Etc., more good toughness and ductility.For more information regarding Nylon 6, please refer to the product page. 

Nylon 66

The name of Nylon 66 is derived from the six carbon atoms contained in hexamethylenediamine and adipic acid in the chemical structure formula. The basic properties of nylon 66 and nylon 6 are similar, but there are still some differences in chemical structure. The density/specific gravity of nylon 66 is 1.14 (g/cm3), the melting point is 260°C, and its crystallinity is higher than that of nylon 6, so it has better rigidity and excellent dimensional stabilityFor more information regarding Nylon 66, please refer to the product page. 

Nylon Composite Material

Nylon composite material refers to a combination of nylon (polyamide) with other reinforcing materials or additives to enhance its properties and performance. The purpose of incorporating these additional materials is to improve specific characteristics of the nylon, such as strength, stiffness, heat resistance, wear resistance, and dimensional stability.

Common reinforcing materials used in nylon composites include:

- Glass fibers (GF): Glass fiber-reinforced nylon, also known as glass-filled nylon or nylon + GF, involves the incorporation of glass fibers into the nylon matrix. The glass fibers provide increased strength, stiffness, and heat resistance to the nylon, making it suitable for applications requiring higher mechanical performance.

- Carbon fibers (CF): Carbon fiber-reinforced nylon, or nylon + CF, utilizes carbon fibers to enhance the mechanical properties of nylon. Carbon fibers offer excellent strength-to-weight ratio, stiffness, and dimensional stability, making the composite material stronger and lighter.

- Mineral fillers: Various mineral fillers, such as talc, mica, or glass beads, can be added to nylon to improve its dimensional stability, reduce shrinkage, and enhance its resistance to deformation and warping.

The addition of these reinforcing materials to nylon creates a composite material that retains the base properties of nylon while incorporating the desired characteristics of the reinforcement. Nylon composites can be tailored to meet specific application requirements by adjusting the type, content, and distribution of the reinforcing materials.

Nylon composite materials are widely used in industries such as automotive, aerospace, electrical and electronic, consumer goods, and industrial equipment, where the combination of nylon's inherent properties with the added reinforcement offers improved performance, durability, and reliability.Please refer to product  and application pages for more detailed information, or contact us to produce customised solutions.

Injection Moulding Defects and Countermeasures
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Dedect Cause Countermeasure
Insufficient filling Insufficient injection pressure Increase the injection pressure
Insufficient resin amount Increase the resin amount
Low barrel temperature Extend the injection cycle or increase the temperature slowly
Low mold temperature Increase the injection pressure.
Poor air exhaust Improve the vent
Air bubble The different thickness of the moulded product will easily cause the curing speed of the thick and thin surface to be different, causing the thicker part to sag and form a vacuum cavity.
The moisture in the resins itself volatilizes or the additives are decomposed by heat, and a large number of bubbles are formed due to the pressure drop in the injection mould.
Increase the resin temperatures
Increase the injection pressure
Increase mould temperatures
Increase the runner or gate size
Increase the back pressure
Increase the holding period
Decrease the injection speed
Dry resins fully
Flash The fluidity of the resins is too good when it is overheated, and there is excess film on the finished product after excessive pressure holding Decrease the injection temperatures
Reduce the injection pressure and the rate of fire to cut into the pressure in advance
Reduce the mould temperature and reduce the holding time
Increase clamping force due to insufficient clamping force
 Crack Overfill Reduce injection pressure time speed and dose
Low mould temperature Increase mould temperatures
Improper demoulding design such as angle oblique position and undercut position Modify the mould
Improper thimble or ring position Place the thimble to eject the finished products out of the mould smoothly
Flow pattern Low injection and  mould temperature and small gate, resulting in jetting mark Increase plastic temperature and mould temperature
Low injection pressure and injection rate, resulting in corrugated on the product surface Increase the injection pressure , speed and the exhaust
Silver Streaks Low injection and mould temperature, resulting in slow filling, so the temperature of the nozzle is too high to cause the problem of cold slug Improve the control of the bottom pressure and back pressure of the machine, increase the plasticization and reduce the effective flow rate during feeding to reduce the internal pressure of the injection area
Water in plastic turns into a liquid state due to compression. When the extrusion nozzle connects the mould,  the pressure suddenly drops and the liquid evaporates into a gaseous state. When the resins come into contact with the mould surface, silvery white streaks are formed due to tiny bubbles on the surface after curing Dry resins, strengthen screw exhaust air, increase back pressure,  and reduce pressure
Weld line When the resin flows through the hole, it is blocked by the heated air when it is divided and recombined. Increase the temperature of the resins or increase the speed of the plastic through the hole
Increase the mould temperature or use a material with better fluidity
Increased injection rate and pressure
Check whether the heater is faulty
Check the moisture content of raw materials
Shrink The plastic has begun to harden when it hits the surface of the mould, and the density of the plastic has begun to differentiate between the molten plastic and the solidified plastic, so it begins to shrink.
Especially for products with irregular thickness, the shrinkage will be more obvious when the thick body injection pressure at the end of the thin surface cannot be replenished.
Increase the resin amount
Increase the injection pressure
Increase the holding time
Reduce the barrel temperature
Reduce the moulding temperature
Increase the exhaust
Warpage & Deformation Released from the mould under too high temperature Reduce the injection temperature
Reduce the moulding temperature
Extended cooldown
Low temperature in resins Increase the melt barrel temperature
Increase core plate temperature
Increase screw back pressure
Incomplete surface Low injection pressure Increase the injection pressure
Insufficient resin amount Increase the injection amount
Short injection period Increase the injection period
Slow injection speed Increase the injection speed
Insufficient back pressure Increase the back pressure
Worn screw or backstop ring Remove and inspect the rubber head group or replace it
Insufficient machine energy Replace the machine
Rough Surface Low mould temperature Increase mould temperatures
Low injection pressure Increase the injection pressure
Moisture in the mould wall Clean and repair water leaks and cracks
Using too much release agent Clean the mould and use a small amount of release agent
Slow injection speed Increase the injection pressure
Increase the  melt temperature