Injection Moulding Nylon: The Strong, Versatile Choice for Engineering Plastics

Nylon consistently shows its worth for demanding applications. It’s strong, wear-resistant, heat- and chemical-resistant, and can be moulded into complex shapes that other materials struggle with.

From automotive engine components to industrial gears, nylon plays key roles that other plastics struggle to match.

Understanding what makes nylon work – and where it doesn’t work – helps you specify the right material for your plastic injection moulding project.

What Makes Nylon Different

Nylon, technically a polyamide (PA), is a semi-crystalline thermoplastic with mechanical properties that rival those of some metals whilst remaining lightweight. The two most common types in plastic moulding are Nylon 6 (PA6) and Nylon 66 (PA66), each with slightly different characteristics.

What sets nylon apart:

• Tensile strength comparable to some metals at a fraction of the weight
• Wear resistance of the surface naturally minimising friction
• Heat tolerance with continuous use above 100°C, some grades up to 150°C
• Chemical resistance to oils, fuels, weak acids, and most solvents
• Fatigue resistance that lets parts withstand bending, flexing, and stress without failing

These properties mean nylon handles mechanical stress, elevated temperatures, and chemical exposure that would degrade other plastics.

Processing Nylon

The injection moulding process for nylon needs specific attention. The material has low melt viscosity, so it flows easily through tight channels and thin sections, making complex geometries and thin-walled parts feasible.

However, nylon needs thorough drying before moulding because it absorbs moisture from the air. Leave it sitting around, and it’ll soak up enough water to cause problems during moulding.

Processing parameters need careful control too – higher mould temperatures than those used for many plastics to achieve proper crystallinity, which affects final part strength.

Glass-filled nylon takes performance further. Adding glass fibres dramatically increases strength and stiffness whilst improving heat resistance. These variants handle higher loads and temperatures, making them suitable for structural applications that previously needed metal.

Where Nylon Excels

So where does nylon tend to show its worth? Below are some of its potential uses:

• Gears and bearings are natural fits for nylon. The low friction and wear resistance provide smooth rotation whilst resisting gradual wear. Unlike metal alternatives, nylon gears run quietly and don’t need lubrication in many applications. Industrial machinery uses nylon bearings, which prevent corrosion and don’t require constant maintenance.
• Automotive applications use nylon extensively. Engine covers need to handle heat. Intake manifolds are exposed to both heat and chemical contaminants. Fuel system components deal with aggressive chemicals. Interior clips and structural parts need strength without adding weight. Nylon handles all of it.
• Electrical housings rely on nylon’s insulation properties combined with mechanical strength. Connectors, cable ties, and electrical enclosures use the material’s resistance to electrical breakdown. When extra rigidity and heat resistance are needed, glass-filled nylon steps in.
• Industrial equipment – conveyor components, rollers, machine parts – uses nylon’s combination of toughness and wear resistance. The material handles continuous operation in demanding environments whilst maintaining dimensional stability. Chemical resistance allows use where oils, solvents, or cleaning agents are present.

Potential Drawbacks

Nylon isn’t perfect for everything. Moisture absorption is the main issue – the material soaks up water from air, causing dimensional changes and affecting mechanical properties.

Parts for humid environments need to be designed to account for swelling. Some applications require moisture-barrier coatings or lower-absorption grades, such as Nylon 12.

Chemical resistance is generally good, but strong acids and bases can attack nylon. UV exposure degrades it too unless you add stabilisers. Shrinkage is typically higher than that of many plastics as well – experienced moulders compensate through mould design and process control. Finally, sharp corners can significantly reduce impact strength.

Nylon vs Polyester

Polyester remains dimensionally stable and absorbs little moisture, making it attractive for precision parts in varying humidity conditions. But nylon handles impact better, resists wear more effectively, and performs better under cyclic loading.

For a gear that’s going to rotate constantly under load, nylon usually wins. For an electrical housing that needs to maintain precise dimensions regardless of humidity, polyester is often the better choice. The choice comes down to which properties your application can’t compromise on.

Working With BEC Group

At BEC Group, we’ve been moulding nylon components since 1976. Our experience covers nylon moulding across automotive, industrial, electrical, and consumer sectors. Whether you need gears, housings, structural parts, or bearings, we can advise on the right nylon specification and produce components to exacting standards. Contact us to discuss your nylon plastic injection moulding project.

For more information on Injection Moulding Nylon: The Strong, Versatile Choice for Engineering Plastics talk to BEC Group