Extrusion method and apparatus

An extrusion method for forming a length of multimaterial extrudate, the method comprising:

• providing a die comprising a longitudinal axis;
• providing a container comprising a multimaterial feed material supply comprising at least two materials,
• the die and the container being configured such that the container is rotatable relative to the die about a rotation axis;
• aligning the longitudinal axis of the die so as to be coincident with the rotation axis;
• rotating the container relative to the die about the rotation axis;
• effecting relative movement of the container towards the die so as to bring an axial surface of the die into contact with a rotating engagement surface of the supply of feed material;
• generating heat at the interface between the axial surface of the die and the rotating engagement surface of the multimaterial feed material supply so as to heat the at least two materials of the multimaterial feed material supply by the application of a contact pressure between the axial surface of the die and the rotating engagement surface of the feed material supply so as to generate friction therebetween;
• pressing the heated multimaterial feed material supply through an orifice in the axial surface of the die and into an extrusion channel in the die so as to form a length of multimaterial extrudate in the extrusion channel.