Methods of manufacturing honeycomb-structure-forming extrusion dies having a number of slots for use in producing extruded articles having complex honeycomb patterns and extrusion dies for use in the manufacture of extruded honeycomb bodies. The method includes inserting a die insert having a runner and a number of teeth into a slot of an extrusion die such that each of the teeth blocks at least a portion of the slot of the extrusion die. The method further includes separating the runner from the teeth so that the teeth remain within the slot of the extrusion die.

A system for controlling center-to-outer flow distribution of extrudate source material through an extrusion die suitable for production of a honeycomb extrudate, and a method for fabricating a honeycomb extrudate, are provided. Sequentially arranged first and second plates define first and second pluralities of openings through which extrudate source material may flow, wherein at least some openings of the second plurality of openings arranged at different radial positions differ in area. Relative movement between the first plate and the second plate may be effectuated to adjust overlap between corresponding openings of the plates, thereby adjusting a center-to-outer flow distribution of extrudate source material through an extrusion die arranged downstream of the first and second plates.

A flow speed control plate is provided for use in combination with a die for forming a monolith. The flow speed control plate includes: a base plate having both a clay supply surface and a clay outflow surface that is to be superposed on a clay inflow surface of the die; clay flow holes which each penetrate the base plate and through which the clay flows from the clay supply surface to the clay outflow surface; and a positioning mechanism provided to position the flow speed control plate with respect to the die so that each of the clay flow holes of the flow speed control plate has its central axis arranged coaxially with a central axis of a corresponding one of clay inflow holes of the die. Moreover, a diameter of the clay flow holes is set to be smaller than a diameter of the corresponding clay inflow holes.