Machining PA66 GF50 black

PA66 GF50 black is a polyamide 66 with aromatic components in the polymer chain, reinforced with 50 % glass fibres. The very high reinforcement and the modified matrix result in a material with near-metal stiffness, the highest creep and fatigue resistance and improved thermal stability – for structural parts permanently exposed to high mechanical and thermal loads. PA66 GF50 black achieves a tensile modulus of 8,700 MPa, a yield stress of 115 MPa and a flexural strength of 200 MPa at a continuous service temperature of 130 °C and a glass transition temperature of 78 °C. The coefficient of linear thermal expansion of 40 · 10⁻⁶/K (23–60 °C) is close to that of aluminium, and moisture absorption of 0.1 % (24 h) is very low for a polyamide – both ensure high dimensional stability. The material is resistant to oils, greases and fuels and easy to machine. The high glass fibre content makes the material brittle (elongation at break 2 %) and highly abrasive to tools; properties are direction-dependent according to fibre orientation and the density of 1.61 g/cm³ is high.

PA66 GF50 black can be machined using all conventional cutting methods; carbide tools are required because of the abrasive glass fibres; sharp cutting edges and good cooling via chip removal avoid heat build-up and residual stresses in the part. For tight tolerances and thick-walled parts, we recommend intermediate annealing to relieve machining stresses; for tight fits, the moisture absorption of the polyamide must be taken into account.

PA66 GF50 black is used wherever metal parts are to be replaced by a highly stiff, dimensionally stable plastic – for example in mechanical engineering, the automotive industry and the electrical industry:

• Structural parts and brackets as metal replacement
• Gears, cams and coupling parts under high permanent load
• Insulating and carrier parts with high stiffness and heat deflection

PA66 GF50 black is calculated individually based on drawing or sample. The part price is determined mainly by the semi-finished form and dimensions, material utilisation and offcuts, machining effort and batch size. We are happy to provide binding prices on request.

The limits of the material are equally important:

• Brittle behaviour, very low elongation at break
• Highly abrasive, direction-dependent properties, high density
• Not generally declared for food contact (see FDA declaration)

An honest assessment:

• Advantage: Highest stiffness and strength (50 % glass fibre)
• Advantage: Very high creep and fatigue resistance
• Advantage: High dimensional stability, low thermal expansion and moisture absorption
• Advantage: Continuous service up to 130 °C, resistant to oils and fuels
• Disadvantage: Brittle behaviour, very low elongation at break
• Disadvantage: Highly abrasive, direction-dependent properties, high density
• Disadvantage: Not generally declared for food contact (see FDA declaration)