Manufacturing method of plugged honeycomb structure

A manufacturing method of a plugged honeycomb structure including a cylindrical honeycomb substrate in which a plurality of cells having two opening end portions are separated by partition walls and formed so as to communicate with both end surfaces of the honeycomb substrate, and plugging portions arranged so as to plug one of the two opening end portions of the cells and form a complementary checkered pattern with one end surface and the other end surface of the honeycomb substrate, the method comprising:

• a first attaching and perforation step of attaching a first mask film to one of the end surfaces of the honeycomb substrate, and making slurry permeation holes at portions of the first mask film corresponding to the one opening end portion of each of the predetermined cells;
• a first filling step of submerging, into a plugging slurry, the one end surface of the honeycomb substrate to which the first mask film has been attached, and filling the one opening end surface of each of the predetermined cells with the plugging slurry;
• a second attaching and perforation step of attaching a second mask film to the other end surface of the honeycomb substrate, and making slurry permeation holes at portions of the second mask film corresponding to the one opening end portion of each of the predetermined cells;
• an air blowing step of allowing air to flow from the other end surface of the honeycomb substrate into the cells so that the air is discharged with a pressure of 0.05 to 5 MPa between the first mask film at the one end surface of the honeycomb substrate and the honeycomb substrate;
• a second filling step of submerging, into the plugging slurry, the other end surface of the honeycomb substrate to which the second mask film has been attached, and filling the one opening end portion of each of the predetermined cells with the plugging slurry to obtain a slurry filled substrate;
• and
• a firing step of firing the resultant slurry filled substrate.