Patent ID: 8038817

Claim:
A method of filling a plug material paste, comprising: obtaining a honeycomb structure comprising a plurality of cells extending along a longitudinal direction of the honeycomb structure; imaging an end face of said honeycomb structure, wherein the end face comprises a plurality of cell openings; identifying a plurality of first openings among the plurality of cell openings to be filled with the plug material paste; determining a coordinate of a first center of gravity for each of the first openings; obtaining an opening-sealing mask comprising a plurality of second openings, wherein the number of the first openings corresponds to the number of the second openings; determining a coordinate of a second center of gravity for each of the plurality of second openings; selecting a number of the first centers of gravity and a corresponding number of the second centers of gravity wherein all of the first openings except those located within two rows at the periphery of the honeycomb structure and a corresponding number of second openings are selected; calculating a value of deviation between the coordinates of selected first centers of gravity for the plurality of first openings and the coordinates of selected second centers of gravity for the plurality of second openings using the method of least squares; comparing the value of deviation with a predetermined value; designating the honeycomb structure as defective when the value of deviation is larger than the predetermined value and designating the honeycomb structure as non-defective when the value of deviation is equal or smaller than the predetermined value; subjecting the honeycomb structure determined as non-defective to subsequent steps of the method of filling a plug material paste; shifting the position of the opening-sealing mask to align each of the plurality of second openings with each of the plurality of first openings of the honeycomb structure determined as non-defective so that the value of deviation is minimized; and injecting the plug material paste into the first openings through said second openings in an alternately plugged manner over the entire end face of the honeycomb structure.