Honeycomb structure forming die and method of manufacturing honeycomb structure forming die

1. A honeycomb structure forming die used for extrusion molding of a honeycomb structure that has a plurality of cells partitioned by cell walls, the honeycomb structure forming die comprising:

a die body;

a material supply portion including

a material supply surface that forms one surface of the die body, and

a material supply hole that extends in an extrusion direction from the material supply surface; and

a slit portion including

an extrusion surface that faces the material supply surface across the material supply hole, and

a slit that has a grid shape, opens on the extrusion surface, and communicates with the material supply hole inside the die body, wherein

the slit has a grid point,

the material supply hole is provided at a position corresponding to the grid point and coaxially with the grid point,

an end of the material supply hole in the extrusion direction includes

a throttle hole whose diameter decreases toward the grid point, and

a guide hole that extends outward from the throttle hole and guides a material to the slit including the grid point,

the slit includes a slit groove that extends from the grid point,

the guide hole is defined between a pair of surfaces that face each other across the slit groove, and

each surface of the pair of surfaces has a shape whose width increases in the extrusion direction.

2. The honeycomb structure forming die according to claim 1 , wherein

the guide hole includes

a first opening that opens on an inner circumferential surface of the throttle hole and extends along the inner circumferential surface, and

a second opening that opens to the slit.

3. The honeycomb structure forming die according to claim 1 , wherein

the material supply hole includes a supply taper hole that is located at an end adjacent to the material supply surface, and

the supply taper hole has a tapered cross section whose diameter increases toward the material supply surface.

4. The honeycomb structure forming die according to claim 1 , wherein

inner surfaces of the material supply hole, the throttle hole, and the guide hole have a smooth curved surface or flat surface, the inner surfaces being smoothly connected to each other.

5. The honeycomb structure forming die according to claim 1 , wherein

the slit has a polygonal grid shape,

the slit includes

a plurality of grid points, and

a plurality of slit grooves each of which extends between two adjoining grid points of the plurality of grid points, and

the material supply guide hole is provided for each of the plurality of slit grooves.

6. A method of manufacturing the honeycomb structure forming die according to claim 1 , the material supply hole and the slit being formed in the honeycomb structure forming die, the method comprising:

laying metal powder on a pedestal; and

applying a laser beam to the metal powder to melt and solidify the metal powder in an area other than portions corresponding to the material supply hole and the slit.