PA6 GF30 Versus GF50: When Should You Step Up to GF50?

Data comparison

Typical PA6 GF30: density 1.36 g/cm³, tensile strength 165 MPa, flexural modulus 8,500 MPa, notched impact 11 kJ/m², HDT 205 °C.

Typical PA6 GF50: density 1.56 g/cm³, tensile strength 205 MPa, flexural modulus 14,000 MPa, notched impact 13 kJ/m², HDT 215 °C. Strength and modulus climb clearly, but impact barely improves.

The real cost of GF50

Lower flow makes thin walls hard to fill, usually demanding larger gates and higher injection pressure, which in turn raises internal stress.

Fibre show: at 50% loading fibres break through the surface readily, so cosmetic parts are largely out; internal parts or post-painting are the only options.

Tool wear: high glass loading accelerates abrasion of screw, barrel and tooling — especially gates and cores — and upgraded steel belongs in the cost model.

When GF50 is genuinely needed

Structural parts where flexural modulus is the governing design constraint — brackets replacing die-cast aluminium, automotive engine mounts, industrial parts under sustained static load.

Where deflection allowance is generous and impact loading dominates, GF30 or even toughened GF25 usually fits better and saves tooling cost.