Apparatus and method for manufacturing products

A method of manufacturing products, the method comprising:

• extruding at least one first material through an extrusion aperture defined in a die to form an extrudate body, varying the rate of flow of at least one first material through the extrusion aperture, periodically increasing or decreasing the flow of the, or at least one of the, first material(s) through the extrusion aperture by periodically moving a moveable member in the form of a flexible element to vary the rate of flow of the or each first material entering the die using a control system including a first material flow control mechanism comprising the flexible element which is at least partially located in a first material supply path and movable to vary the volume of the supply path, the arrangement being such that movement of the flexible element in one direction increases the volume of the supply path and that movement of flexible element the opposite direction decreases the volume of the supply path, so as to produce an extrudate body having a series of bulges or regions of increased cross-sectional area along its length;
• wherein the extrusion die comprises at least one inner fluid outlet;
• and a second material delivery system for delivering a second material in a flowable state under pressure to the at least one inner fluid outlet for introduction into the extrudate body to form a chamber filled with the second material within the extrudate body;
• the method further comprising varying the rate of flow of the second material through the at least one inner fluid outlet by periodically moving a moveable member in the form of a flexible element to vary the rate of flow of the second material through the at least one inner fluid outlet using a control system including a second material flow control mechanism comprising the flexible element which is at least partially located in the second material supply path and movable to vary the volume of the supply path, the arrangement being such that movement of the flexible element in one direction increases the volume of the supply path and that movement of flexible element the opposite direction decreases the volume of the supply path;
• so as to produce an extrudate body comprising alternate filled and intermediate sections, the filled sections having at least one chamber filled with the second material.