1. Field of the Invention
The present invention relates to a die for forming a honeycomb structure and a method of manufacturing the same, and more particularly, to a die for forming a honeycomb structure having a long service life and a method of manufacturing the same.
2. Description of Related Art
Heretofore, a die for forming a honeycomb structure is formed, for example, by stacking a second plate-shaped portion having a plurality of back holes opened on both sides and a first plate-shaped portion having slits communicating with the back holes formed in the second plate-shaped portion. In such a die for forming a honeycomb structure, for example, a first plate-shaped member and a second plate-shaped member having back holes are bonded through a hot pressing process, and slits communicating with the back holes are formed in the first plate-shaped member (for example, refer to Patent Document 1). Such a die for forming a honeycomb structure is used as an extrusion die for manufacturing a ceramic honeycomb structure by extruding a ceramic raw material.
Meanwhile, in the aforementioned die for forming a honeycomb structure, a width of the slit is much narrower than a diameter of the back hole. For this reason, as a ceramic raw material is introduced into the back holes, a pressure inside the back holes increases, so that a stress may be concentrated on the slits. Therefore, the slits may be easily worn or deformed disadvantageously.
For such problems, a die for forming a honeycomb structure, capable of suppressing wear or deformation of the slit has been discussed (for example, refer to Patent Document 2).
The die discussed in Patent Document 2 includes a forming trench having a lattice shape having a cross-sectional shape matching the cross-sectional shape of the honeycomb structure to be formed, and a forming portion that is formed of wear-resistant alloy and has a plurality of “apertures (cavities) having a substantially rectangular cross section” communicating with the forming trench. In addition, the die discussed in Patent Document 2 has a die base portion arranged in a “surface side of the forming portion where ‘the aperture’ is formed.” The die base portion has a through-hole portion (back hole) communicating with the “aperture” of the forming portion.