A masking method for honeycomb formed body, including bonding a film on at least one bottom face of a honeycomb formed body in a quadrangular prism shape such that an adhesive surface is in contact with the bottom face. The step of bonding the film includes bonding of the film so as to have a bottom face covering portion that covers a whole surface of the bottom face and a pair of outer edge portions along one pair of opposite sides of a quadrangle defining an outer peripheral shape of the bottom face and a pair of protruding portions protruding from another pair of opposite sides of the quadrangle. At least a part of the adhesive surface of each of the pair of protruding portions is bonded so as to be in contact with a pair of opposing lateral faces of the honeycomb formed body.

A method of plugging a honeycomb body is disclosed herein, the method comprising: applying a mask layer to the honeycomb body defining a plurality of channels, wherein the mask layer defines a plurality of holes aligned with the plurality of channels; rotating a roller drum; moving the honeycomb body over the roller drum to define a nip between the roller drum and the honeycomb body; and inserting a plugging cement in the nip between the roller drum and the mask layer such that the roller drum forces the plugging cement through the plurality of holes of the mask layer into the plurality of channels of the honeycomb body.

A system and method to dry plug cement in a ceramic honeycomb body during the manufacture of plugged ceramic honeycomb bodies. The system includes a heating element (520) configured to immediately heat without contact a face (502) of a ceramic honeycomb body (500) plugged with a wet plug cement (510) to rapidly dry and stiffen the plug cement (510) on the face (502) of the ceramic honeycomb body (500). The method includes immediately applying heat without contact to a face (502) of a ceramic honeycomb body (500) having wet plug cement (510) disposed in channels (508) of the ceramic honeycomb body at the face, and rapidly drying and stiffening the plug cement on the face of the ceramic honeycomb body.

A bottom face processing method of a pillar-shaped honeycomb structure including steps of: preparing a pillar-shaped honeycomb structure including a plurality of first cells which extend in parallel with each other from a first bottom face to a second bottom face, and each of which is opened in the first bottom face and has a protruding plugged portion in the second bottom face, and a plurality of second cells each of which is adjacent to at least one of the first cells with a partition wall interposed therebetween, which extend in parallel with each other from the first bottom face to the second bottom face, and each of which has a protruding plugged portion in the first bottom face, and is opened in the second bottom face; and removing the protruding portion from the plugged portion of each of the first cells and the second cells of the pillar-shaped honeycomb structure.

A method of plugging a honeycomb body is disclosed herein, the method comprising: applying a mask layer to a honeycomb body comprising a plurality of channels; forming a plurality of holes in the mask layer such that the plurality of holes are aligned with the plurality of channels; positioning a nozzle defining an opening proximate the mask layer; moving at least one of the nozzle and the honeycomb body relative to one another; and passing a plugging cement through the opening defined by the nozzle against the mask layer such that the plugging cement passes through the plurality of holes in the mask layer and enters the plurality of channels of the honeycomb body.

A method for plugging a subset of cells of a honeycomb structure that includes: covering a first end face of the honeycomb structure with a mask that comprises a body and a plurality of openings, wherein the plurality of openings of the mask is coincident with a plurality of cells of the honeycomb structure; providing a plenum, a movable plunger and a flow plate; positioning a cylinder between the honeycomb structure and the plenum; dispensing a plugging material into the plenum; moving the plunger toward the flow plate with a force to push the plugging material through the flow plate into the cylinder, the moving generating a pressure in the plenum and the cylinder that forces the plugging material through the mask into the plurality of cells of the honeycomb structure to a predetermined depth; and determining the pressure within the cylinder during the moving of the plunger.

A honeycomb structural body includes: a porous cell wall that partitions a cylindrical casing; and a large number of cells extending in the axial direction X thereof and alternately blocked at an upstream end face. The large number of cells include plugged cells having plugs and penetrating cells that do not have the plugs. The plugged cells and the penetrating cells both include complete cells and incomplete cells. At least some of plugged incomplete cells of the incomplete cells have a cross-sectional area smaller than a cross-sectional area of penetrating complete cells, and are configured as blocked cells that are entirely blocked inside in the axial direction.

A method of plugging channels of a honeycomb body and a honeycomb body including plugged channels. The method includes applying a shear force to a plugging mixture including a plurality of inorganic particles, clay, and a liquid vehicle to alter the viscosity of the plugging mixture from a first viscosity prior to the vibrating to a second viscosity which is less than the first viscosity. A honeycomb body is placed into contact with the plugging mixture such that a portion of the plugging mixture having the second viscosity flows into the plurality of channels. Application of the shear force is stopped or reduced to increase the viscosity of the portion of the plugging mixture in the plurality of channels to greater than the first viscosity.

A method for producing a ceramic honeycomb filter having a ceramic honeycomb structure having plugs in predetermined cells: comprising using an apparatus having a reservoir having an inlet for a plugging material slurry and an upper opening, a porous plate with pluralities of openings covering the upper opening of the reservoir, and a holding member fixed to an upper end of the reservoir; keeping a lower surface of the sealing film attached to a lower end surface of the ceramic honeycomb structure apart from an upper surface of the porous plate by a distance D of more than 0 mm and 2.0 mm or less; supplying a predetermined volume of the plugging material slurry into the reservoir to introduce it into the predetermined cells of the ceramic honeycomb structure; rotating the ceramic honeycomb structure after sealing of the ceramic honeycomb structure is released; and lifting the ceramic honeycomb structure after the rotation starts.

A plugged honeycomb structure in which in a cross section of a honeycomb structure body which is perpendicular to an extending direction of cells, inflow cells are disposed to surround an outflow cell, and the number of the inflow cells is larger than the number of the outflow cells, and the cross section has a plurality of intersecting portions of partition walls each defining the inflow cells which are adjacent to each other, and in 60% or more of a total number of the intersecting portions, a relation between a diameter (D.sub.1) of a circle inscribed in the intersecting portion and a diameter (D.sub.0) of a circle inscribed in the partition wall defining the inflow cell and the outflow cell which are adjacent to each other satisfies D.sub.1/(2D.sub.0)=1.20 to 1.80