Extrusion techniques for reducing bow of an extrudate formed from a ceramic forming mixture. Velocities of an outer surface of the extrudate are measured at a plurality of peripherally spaced measurement locations. The velocities are compared to determine whether there is a velocity bias, and the comparison is used to selectively alter the flow of the ceramic forming mixture.

Disclosed apparatus and method to extrude a honeycomb, providing correction in bowing of the extruded honeycomb structure, employs a deflector device having a base plate including an opening aligned in a direction parallel to the extrusion axis through which the plastic material is conveyed to the die. The deflector device includes a bow plate movably mounted to the downstream or upstream side of the base plate. The bow plate includes a constant area aperture. The deflector device positioned upstream of extrusion die imparts a degree of bow reduction by the position of the constant area aperture over the opening imparting a pressure drop gradient on the flow stream entering the die.

In-line inspection and control system to in-situ monitor an extrudate during extrusion. A light beam illuminates a line on the outside circumference of the extrudate skin recording the curvature. A master profile of the illuminated defect-free skin is recorded and compared to successive monitoring of the illuminated skin. Differences from the comparison indicate skin and/or shape defects. A real-time feedback to automatically adjust process control hardware reduces or eliminates the skin and shape defects based on the monitoring and comparison.

An extruder apparatus for the extrusion of a strand of building material for 3D printing of a structural part includes an extruder nozzle and at least one cover element. The extruder nozzle has a discharge opening for the discharge of the strand of building material out of the extruder apparatus. The at least one cover element is designed to cover at least a part of the discharge opening such that an opening cross section of at least one uncovered part of the discharge opening specifies a strand cross section of the discharged strand of building material.

In-line inspection and control system to in-situ monitor an extrudate during extrusion. A light beam illuminates a line on the outside circumference of the extrudate skin recording the curvature. A master profile of the illuminated defect-free skin is recorded and compared to successive monitoring of the illuminated skin. Differences from the comparison indicate skin and/or shape defects. A real-time feedback to automatically adjust process control hardware reduces or eliminates the skin and shape defects based on the monitoring and comparison.

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.

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.

An extrusion apparatus (200) and method to extrude ceramic precursor batch through a die to form a honeycomb extrudate (100), and an apparatus assembly method, are provided. The apparatus comprises a tail ring device (202) comprising a tapered inner opening configured to funnel the batch downstream from upstream extrusion hardware, wherein an inner surface (318,320) of the tail ring device (202) comprises no pockets or protrusions to disrupt batch flow; a bow control device (204) disposed on the tail ring device (202) comprising an aperture (414) defined by shutter plates (S1-S4) to control a bow of the honeycomb body extrudate (100) formed from the batch flowing through the die by adjustment of the shutters (S1-S4); and an edge flow control device (206) disposed on the bow control device (204) comprising edge plates (816) configured to protrude into the batch to control an edge flow of the batch flowing to a periphery of the die.

Disclosed apparatus and method to extrude a honeycomb, providing correction in bowing of the extruded honeycomb structure, employs a deflector device having a base plate including an opening aligned in a direction parallel to the extrusion axis through which the plastic material is conveyed to the die. The deflector device includes a bow plate movably mounted to the downstream or upstream side of the base plate. The bow plate includes a constant area aperture. The deflector device positioned upstream of extrusion die imparts a degree of bow reduction by the position of the constant area aperture over the opening imparting a pressure drop gradient on the flow stream entering the die.