CN111097879A

CN111097879A - Ceramic core and preparation method thereof

Info

Publication number: CN111097879A
Application number: CN201811260924.XA
Authority: CN
Inventors: 胡可辉; 成明; 万力
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-10-26
Filing date: 2018-10-26
Publication date: 2020-05-05

Abstract

The invention provides a ceramic core and a preparation method thereof. This ceramic core includes core main part (1) and encapsulation piece (2), and core main part (1) includes shell (3), is located inside interior runner (6) of shell (3) and sets up discharge opening (4) on shell (3), and interior runner (6) communicate to discharge opening (4), and encapsulation piece (2) encapsulation is in discharge opening (4) department to make shell (3) of core main part (1) form seal structure. According to the ceramic core, the surface roughness of the ceramic core can be improved, and the core removing difficulty of the ceramic core is reduced.

Description

Ceramic core and preparation method thereof

Technical Field

The invention relates to the technical field of ceramic cores, in particular to a ceramic core and a preparation method thereof.

Background

In the investment casting technology, a ceramic core is an essential part for forming a high-precision inner cavity of a metal part, the ceramic core is wrapped in paraffin during the wax pressing process, then shell slurry is coated on the surface of the paraffin, high-temperature dewaxing sintering is carried out after full drying, an inner cavity with a shell and a core is obtained after wax loss, namely an investment precision casting cavity, metal is poured into the cavity, the shell is removed by a mechanical means after the metal is solidified, and the core is removed by a chemical corrosion means, so that the metal part with the inner cavity is obtained.

Because ceramic core is wrapped up in inside by the metal after the pouring, so its desorption is very difficult, adopts high pressure sour alkali lye boiling method depoling at present mostly, in order to make sour alkali lye can permeate, ceramic core need possess certain porosity, and depoling just can go on smoothly, but too high porosity can lead to core intensity to reduce, roughness increases, can't satisfy the pouring demand.

Disclosure of Invention

The invention aims to provide a ceramic core and a preparation method thereof, which can improve the surface roughness of the ceramic core and reduce the core stripping difficulty of the ceramic core.

In order to solve the technical problem, as an aspect of the present invention, a ceramic core is provided, which includes a core main body and an encapsulation block, wherein the core main body includes a shell, an inner flow channel located inside the shell, and a discharge hole arranged on the shell, the inner flow channel is communicated to the discharge hole, and the encapsulation block is encapsulated at the discharge hole, so that the shell of the core main body forms a sealing structure.

Preferably, the discharge holes are distributed on the same non-molding surface of the shell or different surfaces of the shell.

Preferably, the number of the inner flow passages is multiple, and the multiple inner flow passages are arranged in a crossed manner to form a grid structure; or, a plurality of inner flow passages are arranged in parallel.

Preferably, the core body has a material reducing cavity therein.

Preferably, the thickness of the shell is 0.2-2 mm.

Preferably, the internal flow channels are distributed over a portion of the core body having a structural dimension greater than 4 mm.

Preferably, the volume ratio of the inner flow channel to the ceramic core is 1: 2-10.

Preferably, the mandrel body is 3D print formed.

According to another aspect of the present invention, there is provided a method for preparing the ceramic core, comprising:

printing an inner core of a core main body of the ceramic core by adopting a 3D printing technology, wherein the inner core comprises an inner flow channel;

printing a shell outside the inner core, wherein the shell is coated outside the shell, and the shell is provided with a discharge hole;

printing a packaging block, wherein the packaging block can be arranged in the discharge hole, so that the shell forms a sealing structure;

cleaning residual raw materials in the core main body and discharging the residual raw materials from the discharge hole;

and installing the packaging block at the discharge hole.

Preferably, the 3D printing technique is one of: 3D printing of photocuring ceramics, 3D printing of laser powder sintering and 3DP technology.

Preferably, the step of mounting the package block at the discharge hole includes:

drying the ceramic core;

packaging the packaging block with the discharge hole;

and (4) carrying out high-temperature degreasing and sintering on the matching position of the packaging block and the discharge hole.

Preferably, the step of cleaning the residual material in the core body is performed by shaking, blowing or ultrasonic cleaning, rinsing.

The ceramic core comprises a core main body and an encapsulation block, wherein the core main body comprises a shell, an inner flow channel positioned in the shell and a discharge hole arranged on the shell, the inner flow channel is communicated to the discharge hole, and the encapsulation block is encapsulated at the discharge hole, so that the shell of the core main body forms a sealing structure. This ceramic core adopts inside formation inner flow way, and the outside forms sealed housing, can be so that the shell has smooth surface, is convenient for take off the core, effectively reduces ceramic core's the degree of difficulty of taking off the core, and core main part inside has sufficient porosity simultaneously, guarantees inside sour/alkali lye can stretch into the core fast, is convenient for take off the core operation.

Drawings

FIG. 1 schematically illustrates a perspective view of a ceramic core according to an embodiment of the present invention;

FIG. 2 schematically illustrates a rear view structural view of a ceramic core according to an embodiment of the present invention;

FIG. 3 schematically illustrates a first structural internal view of a ceramic core in accordance with an embodiment of the present invention;

FIG. 4 schematically illustrates a rear view of the interior of a second configuration of a ceramic core in accordance with an embodiment of the present invention;

FIG. 5 schematically illustrates a perspective view of the interior of a second configuration of a ceramic core in accordance with an embodiment of the present invention;

fig. 6 schematically shows a control flow diagram of an embodiment of the invention.

Reference numbers in the figures: 1. a core body; 2. packaging the block; 3. a housing; 4. a discharge hole; 5. a material reducing cavity; 6. an inner flow passage.

Detailed Description

The following detailed description of embodiments of the invention, but the invention can be practiced in many different ways, as defined and covered by the claims.

Referring to fig. 1 to 5, according to an embodiment of the present invention, a ceramic core includes a core main body 1 and a package block 2, the core main body 1 includes a shell 3, an inner runner 6 located inside the shell 3, and a discharge hole 4 disposed on the shell 3, the inner runner 6 is communicated to the discharge hole 4, and the package block 2 is packaged at the discharge hole 4, so that the shell 3 of the core main body 1 forms a sealing structure.

This ceramic core's inside forms interior flow path 6, and the outside forms sealed shell 3, can be so that shell 3 has smooth surface, and the porosity is less, is convenient for take off the core, effectively reduces ceramic core's the degree of difficulty of taking off the core, can form sufficient porosity in core main part 1 inside simultaneously, guarantees inside sour alkali lye can permeate the core fast, is convenient for take off the core operation.

The discharge holes 4 are distributed on the same non-molding surface of the shell 3 or different surfaces of the shell 3. When a plurality of discharge openings 4 distribute on the same non-profiled surface of shell 3, can increase the number of discharge opening 4 on the basis that does not influence the shaping surface quality, more conveniently clear away the inside raw and other materials of core main part 1 to make things convenient for sour/alkali lye to be convenient for take off core processing in the inside circulation of core main part 1. When a plurality of discharge openings 4 are distributed on different surfaces of the housing 3, the raw material can be removed from a plurality of surfaces of the housing 3, and the removal efficiency is higher.

The number of the discharging holes 4 can be one, so that the number of the packaging blocks 2 can be reduced, and the packaging speed of the core main body 1 can be improved.

In one embodiment, the inner flow passage 6 is provided in plurality, and the plurality of inner flow passages 6 are arranged in a crossing manner to form a grid structure. A plurality of interior runners 6 are alternately arranged, can form topological network structure in the inside of core main part 1 for form interconnection between a plurality of interior runners 6 of inside, conveniently carry out the cleaing away of raw and other materials more, and make sour/alkali lye fast and abundant circulation in core main part 1 is inside, realize ceramic core's quick depoling. The runner structure of inside grid structure form can effectively guarantee ceramic core's porosity for porosity reaches more than 60%, makes ceramic core's structure have sufficient structural strength simultaneously, satisfies ceramic core's intensity operation requirement.

In another embodiment, the inner runners 6 are arranged in parallel, so that the processing difficulty of the ceramic core can be reduced, the processing efficiency is improved, and the processing cost is reduced.

Preferably, the core main body 1 is internally provided with the material reducing cavity 5, and since the central part of the core main body 1 is not a stress point, no requirement is made on the structural strength of the central part of the core main body 1, and the core main body 1 can be made into a hollow structure, so that the porosity of the core main body 1 is improved, the material cost of the core main body 1 is reduced, and meanwhile, the circulation of acid/alkali liquor in the core main body 1 is more convenient.

Preferably, the thickness of the shell 3 is 0.2-2 mm. The shell thickness here refers to the minimum distance from the outer surface of the shell 3 to the wall of the bore of the inner flow channel 6. Set up the thickness of shell 3 to 0.2 ~ 2mm, can enough guarantee that shell 3 has sufficient structural strength, can avoid 3 thickness oversizes of shell to influence ceramic core's porosity again.

The inner flow channels 6 are distributed on the part of the core main body 1 with the structural size larger than 4mm and mainly used for removing raw materials and rapidly circulating acid/alkali liquor.

The topological mesh structure forms an inner core of the core main body 1, the inner core is wrapped by the shell 3, the topological mesh structure is mainly distributed on a core structure part of the core main body 1 with the characteristic dimension larger than 2mm and smaller than 5mm, topological structure meshes with different dimensions are set according to the characteristic dimension of the core, the ratio of the pore volume to the volume of the ceramic core is 1: 2-10, the pore dimension is larger than 0.5mm, all the pores are communicated, the meshes are externally connected with the shell 3, and the inner runner 6 is internally connected.

The discharge opening 4 can be a round hole, a square hole or a hole with other shapes, and when 4 round holes are formed in the discharge opening, the diameter of the discharge opening is larger than 2mm, so that the raw materials in the mold core can be conveniently removed.

Preferably, the core main body 1 is 3D printing forming, so that the forming difficulty of the core main body 1 can be reduced, the forming efficiency and the forming quality of the core main body 1 are improved, a topological network structure is more easily formed in the core main body 1, a smooth surface structure is formed outside the core main body 1, and the processing difficulty of an internal structure is reduced.

The shape of the packaging block 2 is consistent with that of the discharge hole 4, and the packaging block is used for filling the discharge hole 4 after the internal raw materials are removed, so that the ceramic core with a complete shape is obtained.

Referring to fig. 6 in combination, according to an embodiment of the present invention, a method of making a ceramic core as described above includes: printing an inner core of a core main body 1 of the ceramic core by adopting a 3D printing technology, wherein the inner core comprises an inner runner 6; printing a shell 3 outside the inner core, wherein the shell is coated outside the shell 3, and the shell 3 is provided with a discharge hole 4; printing a packaging block 2, wherein the packaging block 2 can be arranged in a discharge hole 4, so that the shell 3 forms a sealing structure; cleaning residual raw materials in the core main body 1 and discharging the residual raw materials from the discharge hole 4; the packaging block 2 is arranged at the discharging hole 4.

The 3D printing technique may be one of: 3D printing of photocuring ceramics, 3D printing of laser powder sintering and 3DP technology.

The step of installing the encapsulation block 2 at the discharge hole 4 comprises: drying the ceramic core; the packaging block 2 is packaged with the discharge hole 4; and (4) carrying out high-temperature degreasing and sintering on the matching position of the packaging block 2 and the discharge hole 4.

The step of cleaning the residual raw material in the core body 1 is performed by vibration, blowing or ultrasonic cleaning and washing.

When the photocuring ceramic 3D printing technology is adopted for printing, one or more of alumina, silica, zirconia, calcium oxide and magnesia ceramic can be adopted for mixing, photocuring ceramic slurry obtained by gradually mixing with photocuring resin and a dispersing agent is subjected to 3-dimensional printing and forming, then ultrasonic cleaning is carried out, all residual photocuring slurry inside is removed from the discharge hole 4, the discharge hole 4 is packaged by the packaging block 2 after drying, and the ceramic core is obtained through subsequent high-temperature degreasing and sintering.

When adopting laser powder sintering 3D printing technique to print, adopt the mixture of one or more in aluminium oxide, silicon oxide, zirconia, calcium oxide, the magnesium oxide pottery, mix with organic polymer powder and obtain mixed powder material, in laser sintering 3D printing apparatus, utilize laser to select the district with polymer powder and melt bonding ceramic powder, print out ceramic core main part 1 and encapsulation piece 2, adopt vibrations, the blast air, ultrasonic cleaning's mode is clear away inside unnecessary powder afterwards, encapsulate with encapsulation piece 2 with discharge opening 4 after the drying, through the high temperature degrease of preface, sintering, obtain ceramic core.

When adopting 3DP printing technique to print, adopt the mixture of one or more in aluminium oxide, silicon oxide, zirconia, calcium oxide, the magnesium oxide pottery, spherical powder is better with the quasi-spherical powder, spout the drop successive layer through the location of binder and bond the printing in 3DP former, print out ceramic core main part 1 and encapsulation piece 2 respectively, adopt vibrations afterwards, the air blast, ultrasonic cleaning's mode is clear away inside unnecessary powder, encapsulate 2 with ejection of compact hole 4 with encapsulation piece after the drying, through the high temperature degrease of preface, sintering, obtain ceramic core.

When the packaging block is used, the discharge hole 4 can be packaged by the packaging block 2, after degreasing and sintering, wax pressing, shell making, sintering, pouring and shelling are carried out, the packaging block 2 is taken out again, and then acid/alkali liquor is adopted for removing.

The ceramic core prepared by the method has the advantages that the strength can meet the strength use requirement of the core, the porosity reaches more than 60%, and the core removing efficiency is more than 5 times of that of a full-solid ceramic core.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A ceramic core, characterized in that it comprises a core body (1) and an encapsulation block (2), wherein the core body (1) comprises a shell (3), an inner core located inside the shell (3) A flow channel (6) and a discharge hole (4) arranged on the outer casing (3), the inner flow channel (6) is communicated with the discharge hole (4), and the packaging block (2) is packaged At the outlet hole (4), the outer shell (3) of the core body (1) forms a sealing structure.

2. The ceramic core according to claim 1, characterized in that, there are a plurality of said discharge holes (4), and a plurality of said discharge holes (4) are distributed in the same non-contact surface of said shell (3). The forming face or distributed on different faces of the casing (3).

3. The ceramic core according to claim 1, characterized in that, there are a plurality of the inner flow channels (6), and a plurality of the inner flow channels (6) are crossed to form a grid structure; The inner flow channels (6) are arranged in parallel.

4 . The ceramic core according to claim 1 , wherein the core body ( 1 ) has a material-reducing cavity ( 5 ) inside. 5 .

5. The ceramic core according to claim 1, characterized in that, the thickness of the shell (3) is 0.2-2 mm.

6 . The ceramic core according to claim 1 , wherein the inner flow channels ( 6 ) are distributed on the portion of the core body ( 1 ) whose structural size is greater than 4 mm. 7 .

7 . The ceramic core according to claim 1 , wherein the volume ratio of the inner flow channel ( 6 ) to the ceramic core is 1:2˜10. 8 .

8. The ceramic core according to claim 1, wherein the core body (1) is formed by 3D printing.

9. A method for preparing a ceramic core as claimed in any one of claims 1 to 8, characterized in that, comprising:

3D printing technology is used to print the inner core of the core body (1) of the ceramic core, wherein the inner core includes an inner flow channel (6);

A shell (3) is printed outside the inner core, the shell is wrapped outside the shell (3), and the shell (3) is provided with a discharge hole (4);

The packaging block (2) is printed, and the packaging block (2) can be inserted into the discharge hole (4), so that the casing (3) forms a sealing structure;

Clean the residual raw material in the core body (1), and discharge the residual raw material from the discharge hole (4);

Install the packaging block (2) at the outlet hole (4).

10 . The preparation method according to claim 9 , wherein the 3D printing technology is one of the following: photocuring ceramic 3D printing, laser powder sintering 3D printing, and 3DP technology. 11 .

11. The preparation method according to claim 9, wherein the step of installing the packaging block (2) at the discharge hole (4) comprises:

drying the ceramic core;

make the packaging block (2) encapsulate the discharge hole (4);

High temperature degreasing and sintering are performed on the matching position of the packaging block (2) and the discharge hole (4).

12 . The preparation method according to claim 9 , characterized in that, the method used in the step of cleaning the residual raw materials in the core body ( 1 ) is vibration, blasting, or ultrasonic cleaning and flushing. 13 .