PA (Nylon) Injection Mould

Characteristics of Nylon

Nylon is known for its high tenacity, wear resistance, self-lubricating properties, and smooth surface finish. It is non-toxic, exhibits antibacterial qualities, and has high water absorbability. However, its tensile strength and stiffness decrease significantly when moisture is absorbed, which can cause noticeable dimensional changes in molded parts. Prolonged exposure to high temperatures may result in degradation.

Nylon does not soften gradually with increasing temperature; instead, it retains its form until reaching its melting point, at which point it begins to flow. It is soluble in various chemicals, though it is resistant to gases, lubricating oils, developers, detergents, and grease.

Advantages of Nylon Injection Mould

• High mechanical strength, toughness, and pressure resistance

• Tensile strength close to its yield strength — approximately twice as strong as ABS

• Excellent fatigue resistance

• Low friction coefficient, smooth surface, and superior wear resistance

• Outstanding chemical resistance, particularly to alkalis and most salt solutions

• Non-toxic, with strong biological inertia and anti-mildew properties

• Good heat resistance and excellent electrical insulation

• Lightweight, easily moldable, and suitable for dyeing

Disadvantages of Nylon Injection Mould

• High water absorption, leading to dimensional instability

• Poor resistance to UV light

• Requires precise control in the molding process

• Swells in alcohol, and lacks resistance to strong acids and oxidizers, making it unsuitable for acid-resistant applications

Molding Process Guidelines

• Precise control of injection parameters is essential to prevent defects such as flashing

• Due to rapid condensation and quick solidification, special attention must be paid to prevent blockages at the orifice, runner, or gate

• Avoid excessively high temperatures, as nylon has poor thermal stability and may yellow

• Injection pressure must be optimized:

• Too high → flashing

• Too low → ripples, flow marks, weld lines, or short shots

• Minimize holding pressure to reduce internal stress in the final product

• Fast injection speed is recommended to counter the rapid cooling rate and prevent incomplete filling or surface defects