Machining PA 6

PA 6 (polyamide 6, also nylon 6) is a semi-crystalline engineering thermoplastic of the polyamide family. It is characterised by high toughness, impact and abrasion resistance, very good sliding properties and pronounced sound and vibration damping. A special feature is its moisture absorption: it increases toughness but reduces stiffness and hardness and changes the dimensions.

PA 6 machines well – turning, milling, drilling and sawing produce clean results with a good surface finish. Because of the moisture absorption and the comparatively high thermal expansion, for tight tolerances we take the swelling and shrinkage behaviour into account and condition the stock if required. This lets us reliably produce precision parts – from single parts to series production.

PA 6 pays off when toughness, wear resistance and good sliding properties at a moderate price are required – for example:

• Highly loaded plain bearings, bushings, gears and rollers
• Impact- and shock-loaded parts (high impact strength)
• Sound- and vibration-damping components
• Wear parts in conveyor technology and mechanical engineering
• Components in food processing (food-grade variants)

PA 6 is one of the economical engineering plastics. As a rough guide, semi-finished stock (natural rod/plate) ranges from about 5–15 €/kg; cast polyamide (PA 6 G), oil- or glass-fibre-filled and coloured grades are higher. The part price is mainly determined by grade, stock form and dimension, material utilisation (waste), machining effort and batch size. We are happy to quote binding prices on request based on your drawing.

Just as important are the limits of the material:

• Highest dimensional accuracy under changing humidity – POM is often the better choice here
• Permanent contact with hot water/steam or strong acids (hydrolysis/attack)
• Continuous use above approx. 85–100 °C or requirements for flame retardancy (only UL 94 HB)
• Applications with very high chemical or temperature requirements – then PVDF, PPS or PEEK
• Precision parts that must stay absolutely dry and dimensionally stable permanently

An honest assessment – and how the disadvantages can be mitigated in practice: Advantages:

Disadvantages:

Practical tip: where the highest dimensional accuracy is required we choose POM; where high temperatures or aggressive chemistry prevail, PVDF, PPS or PEEK. For tough, wear-resistant and damping functional parts, however, PA 6 is the most economical choice – for tight tolerances we condition the stock specifically.

• Very high toughness and impact strength
• High abrasion and wear resistance
• Very good sliding and damping properties
• Good machinability and weldability, low material price
• Good resistance to oils, greases and fuels
• Absorbs moisture – dimensional and property changes
• Not resistant to strong acids and hot water (hydrolysis)
• Not flame retardant (UL 94 HB), limited to approx. 85–100 °C continuous use
• Lower dimensional accuracy than POM under fluctuating humidity