Accuracy analysis of SPH for flow in a model extruder with a kneading element

•Complete SPH solution for a kneading element in the extrusion process with no simplifying assumptions.•Excellent agreement with FEM solutions for the modelling of single kneading element in barrel.•Up to 34 million SPH particles used.•Twin kneading elements SPH results also given.•Method can be extended to include correct heat transfer and shear rates within extruder.