An extrusion die for extruding biodegradable material, the extrusion die comprising: a mandrel; a nozzle extending from the mandrel; an outer member positioned near the mandrel; an extrusion orifice between the mandrel and the outer member; a member in communication with at least one defining member of the extrusion orifice, wherein the member is capable of producing relative movement between the outer member and the mandrel, wherein the relative movement has a component transverse to an extrusion direction of biodegradable material through the extrusion orifice; a flow control device which controls flow of biodegradable material through the extrusion die; and a positioning device which positions the outer member and the mandrel relative to each other.