US-12623427-B2 - Powder feeding device

US12623427B2US 12623427 B2US12623427 B2US 12623427B2US-12623427-B2

Abstract

A powder feeding device configured to fill a saggar with powder by compressing the powder thereinto may include: a pressing plate configured to compress the powder in the saggar; and a pressing mechanism configured to press the pressing plate toward the powder in the saggar. The pressing plate may include a compression plate including a pressing surface that compresses the powder by contacting the powder; and a plurality of slit plates disposed on the pressing surface and extending downward from the pressing surface. The slit plates may be arranged radially as the powder feeding device with the saggar placed therein is viewed from above. When the saggar is placed in the powder feeding device, distances between the slit plates and a sidewall of the saggar may be substantially equal and the distances between the slit plates and the sidewall of the saggar may be 30 mm or less.

Inventors

Taiki KINNAN
Michihiro Ito
Takanori Isono

Assignees

NGK INSULATORS, LTD.
NGK KILNTECH, CORPORATION

Dates

Publication Date: 20260512
Application Date: 20240905
Priority Date: 20220502

Claims (10)

1 . A powder feeding device configured to fill a saggar with powder by compressing the powder thereinto, the powder feeding device comprising: a pressing plate configured to compress the powder in the saggar; and a pressing mechanism configured to press the pressing plate toward the powder in the saggar, wherein the pressing plate comprises: a compression plate including a pressing surface that compresses the powder by contacting the powder; and a plurality of slit plates disposed on the pressing surface and extending downward from the pressing surface, the slit plates are arranged radially as the powder feeding device with the saggar placed therein is viewed from above, when the saggar is placed in the powder feeding device, distances between the slit plates and a sidewall of the saggar are substantially equal, when the saggar is placed in the powder feeding device, the distances between the slit plates and the sidewall of the saggar is 30 mm or less, and each of the slit plates comprises a chamfered or rounded taper having an angle of 20 degrees or more at a lower end thereof.
2 . The powder feeding device according to claim 1 , wherein the plurality of slit plates includes slit plates that coincide with at least diagonal lines of the saggar as the powder feeding device with the saggar placed therein is viewed from above.
3 . The powder feeding device according to claim 1 , wherein a thickness of each of the slit plates is 0.5 mm or more and 4 mm or less.
4 . The powder feeding device according to claim 1 , wherein the taper of each of the slit plates is defined by only one surface of the slit plate being tilted, and an angle of the taper of each of the slit plates is 20 degrees or more and 90 degrees or less.
5 . The powder feeding device according to claim 1 , wherein the taper of each of the slit plates is defined by only one surface of the slit plate being tilted, and an angle of the taper of each of the slit plates is 30 degrees or more and 85 degrees or less.
6 . The powder feeding device according to claim 1 , wherein the taper of each of the slit plates is defined by opposing surfaces of the slit plate being tilted, and an angle of the taper of each of the slit plates is 20 degrees or more and less than 180 degrees.
7 . The powder feeding device according to claim 1 , wherein the taper of each of the slit plates is defined by opposing surfaces of the slit plate being tilted, and an angle of the taper of each of the slit plates is 30 degrees or more and 170 degrees or less.
8 . The powder feeding device according to claim 1 , wherein the slit plates are constituted of one or more materials selected from the group consisting of stainless steel, titanium, nickel, polyvinyl chloride, and tungsten carbide.
9 . The powder feeding device according to claim 1 , wherein surfaces of the slit plates are buffed.
10 . The powder feeding device according to claim 1 , wherein surfaces of the slit plates are coated with polytetrafluoroethylene.

Description

REFERENCE TO RELATED APPLICATION This application claims priority to Japanese Patent Application No. 2022-076143 filed on May 2, 2022. The entire content of the priority application is incorporated herein by reference. TECHNICAL FIELD The art disclosed herein relates to a powder feeding device configured to fill a saggar with powder. BACKGROUND ART For example, when a raw powder material used for an electronic product is to be fired, the powder is supplied into a saggar and then fired. In order to improve the productivity of powder firing, the powder is compressed when supplied into the saggar so that the saggar is filled with the powder more efficiently. However, this may make it hard to remove the sintered powder from the saggar since the powder was compressed and thus densely packed in the saggar. For example, Japanese Patent Application Publication No. 2015-218098 describes a powder feeding device that supplies powder into a saggar by compressing the powder thereinto. The powder feeding device of Japanese Patent Application Publication No. 2015-218098 includes a pressing plate that compresses the powder. The pressing plate includes a plurality of slit plates extending downward from the pressing plate which compresses the powder. The slit plates of the pressing plate form slit grooves in a powder compact formed by filling the saggar with the powder. This facilitates removal of the sintered powder from the saggar after firing. The slit plates are in the same shape and arranged radially as the powder feeding device is viewed from above. SUMMARY In the powder feeding device of Japanese Patent Application Publication No. 2015-218098, the slit plates are arranged radially from the center of the pressing plate. When the powder is compressed by the pressing plate, since the slit plates all have the same shape, the slit plates are not positioned near the four corners of the saggar, which is square as viewed from above. That is, the slit grooves are not formed near the four corners of the saggar. This lack of slit grooves in the powder compact formed by filling the saggar with the powder may hinder gases required for firing reactions from reaching deep inside the powder compact and may also hinder reaction gases generated during the firing from escaping. With the powder feeding device of Japanese Patent Application Publication No. 2015-218098, the reaction gases are less likely to escape from near the four corners of the saggar than from near a center portion thereof. Due to this, the powder in the saggar may be fired homogeneously. The disclosure herein provides a technology that allows powder in a saggar to be homogeneously fired. In a first aspect of the technology disclosed herein, a powder feeding device is configured to fill a saggar with powder by compressing the powder thereinto. The powder feeding device may comprise: a pressing plate configured to compress the powder in the saggar; and a pressing mechanism configured to press the pressing plate toward the powder in the saggar. The pressing plate may comprise a compression plate including a pressing surface that compresses the powder by contacting the powder; and a plurality of slit plates disposed on the pressing surface and extending downward from the pressing surface. The slit plates may be arranged radially as the powder feeding device with the saggar placed therein is viewed from above. When the saggar is placed in the powder feeding device, distances between the slit plates and a sidewall of the saggar may be substantially equal. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 schematically shows a perspective view of a powder feeding device according to first and second embodiments. FIG. 2 shows a top view of a pressing plate and a saggar, where the pressing plate is inserted in the saggar. FIG. 3 shows a side view of the pressing plate and the saggar, where the pressing plate is inserted in the saggar. FIG. 4 shows relationships between distances between slit plates and a sidewall of the saggar and homogeneousness of sintered powder. FIG. 5 shows relationships between thicknesses of slit plates and homogeneousness of sintered powder and relationships between the thicknesses of slit plates and pressing force of a pressing device. FIG. 6 shows a side view of a lower end of a slit plate in the powder feeding device according to the second embodiment. FIG. 7 shows relationships between taper angles α at the lower ends of the slit plates and abrasion resistance of the slit plates and relationships between the taper angles α at the lower ends of the slit plates and pressing force of a pressing device. FIGS. 8A and 8B show side views of lower ends of other exemplary slit plates in the powder feeding device according to the second embodiment. FIG. 9 shows a side view of a lower end of a slit plate in a powder feeding device according to a third embodiment. FIG. 10 shows relationships between taper angles β at lower ends of the slit plates and abrasion resistance of