Interdigitated finger coextrusion device

A co-extrusion device, comprising:

• a first layer of material having at least one array of separating channels and at least one array of splitting channels, the separating channels and the splitting channels having entrances and exits, the first layer of material arranged to receive a first material;
• a second layer of material arranged adjacent the first layer of material, the second layer of material having at least one array of combining channels and at least one array of extruding orifices, the combining channels having entrances and exits;
• a third layer of material, arranged adjacent a side of the second layer of material opposite the first layer of material such that the second layer of material lies between the first and third layers of material, the third layer of material is arranged to receive a second material;
• the exits of the separating channels being aligned with the entrances of the combining channels;
• the exits of the combining channels being aligned with the entrances of the splitting channels;
• and
• the exits of the splitting channels being aligned with the entrances of one of either another array of combining channels or an array of extruding orifices such that the first and second materials exit the extruding orifices to form interleaved stripes of the first and second materials without mixing the first and second materials;
• wherein a first flow path begins at one of the separating channels in the first layer, enters a first of the combining channels in the second layer, returns to a first of the splitting channels in the first layer, ending at one of the extruding orifices in the second layer, the layers of material comprising plates stacked together, such that the first flow path passes through a plate forming the first layer in a first direction, passes through a plate forming the second layer in a direction opposite to the first direction to return to the plate forming the first layer;
• and
• wherein the third layer of material forms a second flow path that begins in a separating channel in the third layer of material, enters a first of the combining channels of the second layer, returns to a first of the splitting channels in the third layer, ending at one of the extruding orifices in the second layer.