Adjusting method of extrusion rate

Patent metadata

Field	Value
Publication number	US-10828819-B2
Application number	US-201615386275-A
Country	US
Kind code	B2
Filing date	Dec 21, 2016
Priority date	Jan 8, 2016
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

In the adjusting method of the extrusion rate, a perforated plate is superimposed on and attached to a forming die, the perforated plate includes a plurality of through hole portions, the adjusting method includes a perforated plate group consisting of a plurality of perforated plates which are different in degree of diameter decrease of the hole diameter, and the adjusting method includes a trial extrusion step of extruding the forming material to form a trial honeycomb formed body, a shape measuring step of measuring a shape of a formed body end face of the trial honeycomb formed body, and a perforated plate selecting step of selecting the perforated plate to be suitably attached to the forming die.

First claim

What is claimed is:

1. An adjusting method of an extrusion rate in which a perforated plate is superimposed on and attached to a forming die for use in extrusion of a honeycomb formed body, to achieve a uniformity of an extrusion rate of a forming material which passes through the forming die at a die surface,
the perforated plate comprising a plurality of through hole portions bored at positions of a perforated plate surface which face back holes opened at a die back surface, to introduce the forming material into the forming die,
the through hole portions being formed so that a hole diameter of the through hole portion decreases from a circumferential portion of the perforated plate toward a central portion thereof gradually or stepwisely,
the adjusting method comprising:
a perforated plate group preparation step of preparing a plurality of perforated plates which are different in degree of diameter decrease of the hole diameter of the through hole portion,
the adjusting method further comprising:
a trial extrusion step of using the forming die to which the perforated plate is not attached, extruding the forming material from the forming die, and forming a trial honeycomb formed body;
a shape measuring step of measuring a shape of a formed body end face of the trial honeycomb formed body; and
a perforated plate selecting step of selecting one perforated plate to be attached to the forming die from the perforated plate group on the basis of a matching relation between the measured shape of the formed body end face and the degree of the diameter decrease of the hole diameter in the perforated plate.

2. The adjusting method of the extrusion rate according to claim 1 ,
wherein the shape measuring step is constituted to measure the shape of the formed body end face which is perpendicular to an extruding direction of the forming material to be extruded to form the trial honeycomb formed body, and comprises:
a contour map preparing step of dividing a height from a circumferential edge of the measured formed body end face to a topmost portion thereof at equal intervals, and preparing a contour map indicating a distribution of the heights of the formed body end face;
a contour line dividing step of dividing the formed body end face into a plurality of end face regions on the basis of the prepared contour map; and
a hole diameter setting step of allotting the divided end face regions to the perforated plate surface of the perforated plate, and setting the hole diameter of the through hole portion so that the hole diameter decreases from an outermost circumference division of the perforated plate toward a central division thereof in accordance with a predetermined reference.

3. The adjusting method of the extrusion rate according to claim 2 ,
wherein the perforated plate selecting step is constituted to select the perforated plate from the perforated plate group on the basis of a matching relation between a difference in height from the circumferential edge to the topmost portion of the formed body end face and the degree of the diameter decrease of the hole diameter.

4. The adjusting method of the extrusion rate according to claim 2 ,
wherein the contour map preparing step is constituted to divide the height from the circumferential edge of the formed body end face to the topmost portion thereof into at least three stages at equal intervals to prepare the contour map, and
the contour line dividing step is constituted to divide the formed body end face into at least three end face regions.

5. The adjusting method of the extrusion rate according to claim 2 ,
wherein when the degree of the diameter decrease is a diameter decrease ratio represented by Equation (1) mentioned below, a value of the diameter decrease ratio is in a range of 7% to 50%:
( X−Y )/ X× 100,  Equation (1):

in which X is a hole area of the through hole portion positioned in the outermost circumference division of the perforated plate, and Y is a hole area of the through hole portion positioned in the central division of the perforated plate.

6. The adjusting method of the extrusion rate according to claim 1 ,
wherein the hole diameter of the through hole portion of the perforated plate is the same as a back hole diameter of the back hole of the forming die or smaller than the back hole diameter.

7. The adjusting method of the extrusion rate according to claim 1 , which further comprises:
a formed body drying step of drying the trial honeycomb formed body formed by the trial extrusion step,
wherein the shape measuring step is constituted to measure the shape of the formed body end face of the trial honeycomb formed body dried in the formed body drying step.

8. The adjusting method of the extrusion rate according to claim 1 ,
wherein in the perforated plate, the perforated plate surface possesses a circular shape or an elliptic shape.

Assignees

• Ngk Insulators Ltd

Inventors

• Ito Hiroaki
• Hamatsuka Kazuhiko

Classifications

• B28B3/269 Primary

  For multi-channeled structures, e.g. honeycomb structures · CPC title

• B29C2948/92114

  Dimensions · CPC title

• B29C48/0022

  combined with cutting · CPC title

• B29C2948/926

  Flow or feed rate · CPC title

• B28B17/0081

  Process control · CPC title