KR102501278B1 - Preform infiltration treatment system and method thereof - Google Patents

Abstract

An embodiment of the present invention is to provide an apparatus and a method for treating preform impregnation, which can integrally heat-treating a subsequent heat treatment process of a preform having a complicated structure using spherical oxide particles as a raw material in one apparatus. According to an embodiment of the present invention, the apparatus for treating preform infiltration comprises: a main body having a guide unit elongated along a preset first direction from an inner center to guide movement of a corresponding crucible; a plurality of heat treatment units having different heating temperatures along the first direction around the guide unit; and an impregnation treatment unit for treating dry, pre-heat treatment, and infiltration of the preform supplied into the guide unit.

Description

Preform impregnation processing device and method {PREFORM INFILTRATION TREATMENT SYSTEM AND METHOD THEREOF}

The present invention relates to a preform impregnation processing apparatus and method.

In general, a preform is manufactured using 3D printing technology of a binder jet method using ceramic powder as a raw material, and a desired object is manufactured by post-processing the preform. The process of making the final target product using oxide as a raw material proceeds through several stages of unit processes.

Manufacture of 3D shape preform using liquid binder and raw material powder → curing/drying → de-powdering → pre-thermal treatment (removal of binder and bonding between particles) → It goes through processes such as infiltration → sintering → finishing. However, the process for heat treatment (pre-thermal treatment ~ sintering) is not specifically mentioned by the 3D printer manufacturer, and there is almost no information on the infiltration furnace.

As related prior art, Korean Patent Registration No. 1,612,425 discloses "a heat treatment apparatus having a continuous vacuum chamber".

Korean registered patent 1,612,425

One embodiment of the present invention is to provide a preform impregnating treatment apparatus and method capable of integrating heat treatment of a preform having a complex structure using spherical oxide particles as a raw material in one apparatus.

In addition to the above tasks, embodiments according to the present invention may be used to achieve other tasks not specifically mentioned.

Preform impregnation processing apparatus according to an embodiment of the present invention is a main body having a guide part that is provided long along a first direction set in advance from the inside center and guides the movement of a corresponding crucible, and different guide parts along the first direction around the guide part. It includes a plurality of heat treatment units having heating temperatures, and an impregnation treatment unit that processes drying, preliminary heat treatment, and impregnation of the preform supplied to the inside of the guide unit.

A preform impregnation treatment method according to an embodiment of the present invention includes preparing a preform manufactured by a 3D printing process of a binder jet method, providing the preform in a first crucible and heating it to a preset first heating temperature in a first heating zone. and an impregnation step of impregnating the preform by raising the second crucible equipped with the melt.

One embodiment of the present invention has an effect of forming a part having a desired quality and shape by treating a preform having a complex structure using spherical oxide particles as a raw material and processing the subsequent heat treatment process with one integrated heat treatment device.

1 is a diagram showing a preform impregnation processing apparatus according to an embodiment of the present invention.
Figure 2 is a view showing the inside of the body of the preform impregnation processing apparatus according to an embodiment of the present invention.
3 is a view showing a state in which the main body of the preform impregnation processing apparatus according to an embodiment of the present invention is opened and closed.
4 is a diagram showing a method of using a preform impregnation treatment apparatus according to an embodiment of the present invention by dividing it.
5 is a diagram showing a step-by-step method of ascending use using a preform impregnation treatment apparatus according to an embodiment of the present invention.
6 is a diagram showing a step-by-step method of using a pressure type using a preform impregnation treatment apparatus according to an embodiment of the present invention.
7 is a diagram showing a gravity-type usage method using a preform impregnation processing apparatus according to an embodiment of the present invention, divided into stages.

With reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the same reference numerals are used for the same or similar components throughout the specification. In addition, in the case of widely known known technologies, detailed descriptions thereof will be omitted.

Throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Hereinafter, a preform impregnation processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a view showing a preform impregnation treatment apparatus according to an embodiment of the present invention, and FIG. 2 is a view showing the inside of the main body of the preform impregnation treatment apparatus according to an embodiment of the present invention. And Figure 3 is a view showing a state in which the main body of the preform impregnation processing apparatus according to an embodiment of the present invention is opened and closed. 1 to 3, a preform impregnation treatment apparatus 10 according to an embodiment of the present invention includes a main body 100, a heat treatment unit, and an impregnation treatment unit, and has a complicated structure using spherical oxide particles as a raw material. (preform) subsequent heat treatment process can be heat treated in an integrated type in one device. That is, it is possible to supplement the operation of existing heat treatment furnaces to perform a single heat treatment process, and to integrate subsequent heat treatment processes including pre-thermal treatment and infiltration in one heat treatment device after preform production. can be heat treated. Here, the preform may be manufactured by a 3D printing process using a binder jet method. Therefore, the drying, pre-heat treatment, and impregnation processes of the preform manufactured by the 3D printing process of the binder jet method can be integrated and heat treated using one preform impregnation processing device 10.

The main body 100 has a guide part that is provided long along a first direction set in advance from the inner center and guides the movement of the corresponding crucible.

The heat treatment unit may be provided in plurality with different heating temperatures around the guide unit along the first direction. The heat treatment unit includes a first heater 110 provided outside the guide unit in the first heating area corresponding to the upper side of the guide unit and heating the first heating area to a preset first heating temperature, and a second heating unit corresponding to the lower side of the guide unit. The area may include a second heater 120 provided outside the guide unit to heat the second heating area to a preset second heating temperature.

The impregnation processing unit may process drying, preliminary heat treatment, and impregnation of the preform supplied into the guide unit. The impregnation processing unit is provided at a position corresponding to the first heating area inside the guide unit to support the impregnation process of the preform, and is provided at a position corresponding to the second heating area inside the guide unit to protect against external force. It may include a second crucible 122 that moves up and down and supports the impregnation process of the preform.

A driving unit provided on the lower side of the second crucible 122 to implement vertical movement of the second crucible 122 may be further included. The driving unit may include a stepper motor.

In general, a preform having a complex structure using spherical oxide particles as a raw material is manufactured using a binder jet 3D printing method, and a part having a desired quality and shape may be formed by subsequent heat treatment.

In order to manufacture ceramic parts using oxide particles as a raw material using the binder jet method,

1) preparing raw material powder in a spherical state having a desired size and particle distribution;

2) manufacturing a structure (preform using the binder jet 3D printing method) of a desired shape using the manufactured spherical powder;

3) curing/drying and de-powdering the powder used in step 2);

4) de-binding the used binder;

5) infiltrating a desired matrix material while heat-treating the cured preform;

6) Step of cleaning and treating the surface of the heat treated product

If this binder jet method is used, the process is relatively simple compared to the existing mechanical manufacturing method, it is possible to produce a variety of products in small quantities, and a 3D printer can be used to produce objects that are impossible to produce complex shapes by mechanical methods. It can be easily produced using In addition, all of the raw material powder used in preform manufacturing can be recovered and reused.

Since the parts manufactured by the binder jetting method are based on the powder packing of the bed, they are made porous. To fill the pores in a component with a material, the component must be sintered or impregnated with another substance. Sintering results in a geometrical shrinkage of the initial part due to material diffusion from the bulk particles or grain boundaries into the pores, with subsequent centers of mass transfer between the grains, whereas impregnation results in shrinkage as the pores are filled with additional molten material. Decrease the distortion phenomenon. However, this part is made of two materials, making it a composite material. Impregnating the porous printed part with metal results in a metal matrix composite. The printed material is formed into a skeleton or preform and the molten metal is the matrix or surrounding material. Composite materials made through binder jet additive manufacturing and subsequent melt impregnation are processed by capillary forces that allow molten material to become entrapped in other solid materials. The metal matrix composite material may be a metal/metal combination or a ceramic/metal composite material (ceramic/metal composite material).

Meanwhile, nuclear fuel used in a small nuclear reactor (SMR) may require a nuclear fuel structure having a special shape based on a type of nuclear fuel used in an existing light water reactor or heavy water reactor. In addition, in order to make a complex nuclear fuel structure, it is advantageous in terms of economics and safety to manufacture it in small quantities and in many varieties using 3D printing. In the case of manufacturing nuclear fuel applicable to small nuclear reactors by 3D printing, making a structure using a laser or ion beam is not applicable in terms of nuclide separation. Among various 3D printing technology methods, it is expected that it is desirable to use the binder jet method, which is a method that has been widely used in addition to the use of lasers or ion beams, from the viewpoint of manufacturing nuclear fuel. The size or particle size distribution of the raw material powder used at this time varies depending on the type of binder jet printer used, and powders having a size of about 20-60 μm are widely used.

There are various routes for making particles with a size of several tens of micrometers. For example, as a method of manufacturing in the form of a sphere, there is a method of manufacturing by a conventional sol-gel method. In the process of manufacturing nuclear fuel by 3D printing, nuclear fuel scrap containing a binder is generated. And it is necessary to develop a recycling process, and research to use the spray drying method is beginning.

When nuclear fuel is produced by 3D printing using particles of several tens of micrometers in size, a complete nuclear fuel preform is made through a de-powdering process and a drying process. In order to use it as nuclear fuel, a de-binding process to remove the used binder and a curing process are performed. And after the first heat treatment, it goes through a sintering process. However, nuclear fuel is manufactured through an infiltration process in which a matrix material (a metal material such as zirconium and a zirconium co-product) is inserted between particles according to a manufacturing type of the nuclear fuel. Impregnation is a densification process that uses an alloy with a lower melting temperature than the 3D printed matrix to remove residual porosity and achieve full density with little change in dimensions. Indeed, the capillary force between the impregnable material and the pores of the powder particle surface is the main driving force in the impregnation process. Impregnation can eliminate pores in the binder sprayed parts to increase density, thus improving the mechanical properties of the final product, including hardness, modulus of elasticity, and yield strength.

The preform impregnation processing apparatus 10 according to an embodiment of the present invention can process the subsequent heat treatment process, which is expected to be performed through several steps after manufacturing the preform, with one integrated heat treatment apparatus. That is, de-binding, bonding between particles, infiltration, and sintering using a vertical heat treatment furnace with two heating zones, a crucible, and accessories can be performed sequentially. Here, the accessory may include a thermocouple, an IR thermometer, a pressurization system, a vacuum system 400, a cooling system, a guide tube, and an internal thermocouple.

In the preform impregnation processing device 10, which is an integrated heat treatment device proposed in the embodiment of the present invention, after manufacturing a preform using ceramic oxide, the de-powdered preform is bound with a weak adhesive force, It is difficult to maintain strong adhesion even during de-binding or pre-thermal treatment. For this reason, the infiltration process can be difficult. Therefore, the concept of the impregnation process proposed in the embodiment of the present invention is a method of raising the melted melt, and can be impregnated by dividing it into a mechanical method and a pressurizing method. And it can be impregnated with the force of gravity.

4 is a diagram showing a method of using a preform impregnation treatment apparatus according to an embodiment of the present invention by dividing it. Referring to FIG. 4, the method of using the preform impregnation treatment apparatus 10 according to an embodiment of the present invention is a rising type or a pressing type according to a change in the location or setting conditions of the heat treatment unit and the impregnation unit provided in the main body 100. , It is possible to change the high-temperature melt impregnation method by dividing it into gravity type. In order to change the positions of the heat treatment unit and the impregnation unit provided in the body 100, an elevation unit 300 connected to the body 100 to open and close the body 100 may be further included. In the process of elevating the main body 100, pipes, wires, sensor wires, etc. connected to the main body 100 may be provided in a flexible form.

First, with reference to FIGS. 1 to 4 , a case in which the preform impregnation treatment apparatus 10 according to an embodiment of the present invention is used in an ascending type will be described. When used as a rising type, the first heating temperature may be set lower than the second heating temperature. The first heating temperature may be set to 600 degrees, and the second heating temperature may be set to 1,600 degrees. A preform may be provided in the first crucible 112 . The main body 100 is lifted and opened by the driving of the elevating unit 300, and then a preform is mounted on the upper first crucible 112. Then, a material to be infiltrated into the lower second crucible 122 is introduced, and the main body 100 is lowered to close it. Subsequently, de-gasing is performed using the vacuum system 400, and the degree of vacuum inside the main body 100 is adjusted. Subsequently, a de-binding process is performed. By operating the first heater 110 mounted outside the first crucible 112, the binder inside the preform is removed with fine temperature control and heating speed. At this time, the removed off-gas may be discharged to the outside through the vacuum system 400 . Harmful gases can be removed by attaching a gas trap to the discharge line. When the de-binding is completed, the first heater 110 is heated to an appropriate set temperature to perform a pre-thermal treatment to improve adhesion by using the properties of the material itself. The heating temperature of the first heater 110 can be adjusted to be turned on or off according to circumstances. The second heater 120 is operated to melt the metal material to be impregnated. The melt formed by heating to the second heating temperature is provided in the second crucible 122, and the preform may be impregnated by raising the second crucible 122 equipped with the melt. Here, the second crucible 122 equipped with the molten material in which the metal material is melted is mechanically raised by using a driving unit installed at the bottom of the second crucible 122 . The size of the second crucible 122 may be larger than that of the first crucible 112 . The rising speed of the second crucible 122 may be set to be controllable through the control unit 200 . The rising speed of the second crucible 122 may be controlled so that the molten material penetrates into the void of the preform subjected to pre-thermal treatment, and may be controlled to facilitate infiltration using a vacuum. When the penetration of the melt into the preform is completed, the temperature is lowered and the second crucible 122 containing the melt is lowered.

On the other hand, when used as a pressure type, the cover 162 provided on the top of the second crucible 122, and the pressure tube connected to the second crucible 122 through the first crucible 112 and the cover 162 (160) may be further included. The melt formed by heating to the second heating temperature is provided in the second crucible 122, and the melt provided in the second crucible 122 is pressurized to feed the melt into the first crucible 112 through the pressure pipe 160. and the preform can be impregnated with the melt. In the case of the pressurized type, basic operation can be performed in the ascending type progress method described above. However, instead of a mechanical lifting method, pressure is applied to the cover 162 of the second crucible 122 through a hole by pressing force so that the molten material rises to the lower part of the upper preform. When penetration of the melt is complete, the temperature can be lowered and the pressure released to allow the melt to return to the bottom.

On the other hand, when used as a gravity type, the first heating temperature may be set higher than the second heating temperature. The first heating temperature may be set to 1,600 degrees, and the second heating temperature may be set to 600 degrees. A preform may be provided in the second crucible 122 . That is, the preform is mounted on the lower second crucible 122, and the second heater 120 is driven to gradually heat it to the second heating temperature to complete de-binding. Heating can be maintained even after debinding and pre-heat treatment are completed.

A melt formed by heating to a first heating temperature may be provided in the first crucible 112 . The first heater 110 is driven to melt the metal material introduced into the upper first crucible 112 . A connecting pipe 172 provided between the first crucible 112 and the second crucible 122 and guiding the molten material provided in the first crucible 112 to be supplied to the second crucible 122, and the first crucible It may include an opening/closing unit 170 provided in the 112 to open and close the connection pipe 172 connected to the first crucible 112 to control the flow of the melt. The hole blocking the inside of the first crucible 112 is opened by turning the screw of the opening/closing control unit provided on the upper part of the main body 100 . The opening/closing control unit is connected to the opening/closing unit 170 and may be provided in a screw shape to enable up/down height adjustment. The void may be impregnated while the molten material descends to the lower preform through the connecting pipe 172 by gravity. The end of the connecting pipe 172 is spaced apart from the preform by a certain distance, so that the melt can descend only to the preform position. When the lowering of the molten material is completed, the hole of the first crucible 112 is closed using the opening/closing part 170 .

5 is a diagram showing a step-by-step method of ascending use using a preform impregnation treatment apparatus according to an embodiment of the present invention. Referring to FIGS. 1 to 5 , a preform manufactured by a binder jet 3D printing process is prepared (S510). Subsequently, a pre-heat treatment step of heating the preform to a first heating temperature set in advance in a first heating region by providing the first crucible 112 is performed. A melt forming step of heating the metal material in the second crucible 122 to a preset second heating temperature in the second heating region is performed (S520). Then, the second crucible 122 equipped with the melt is raised to impregnate the preform (S530).

6 is a diagram showing a step-by-step method of using a pressure type using a preform impregnation treatment apparatus according to an embodiment of the present invention. Referring to FIG. 6, a preform manufactured by a binder jet 3D printing process is prepared (S610). Subsequently, a pre-heat treatment step of heating the preform to a first heating temperature set in advance in a first heating region by providing the first crucible 112 is performed. A melt forming step is performed in which a metal material is provided in the second crucible 122 and heated to a preset second heating temperature in a second heating region (S620). The second crucible 122 and the first crucible 112 having melt formed by being heated to a preset second heating temperature in the second heating region are connected by a pressure pipe 160 . Then, the melt provided in the second crucible 122 is pressurized and the melt is supplied into the first crucible 112 through the pressure pipe 160 (S620). The preform is impregnated (S630).

7 is a diagram showing a gravity-type usage method using a preform impregnation processing apparatus according to an embodiment of the present invention, divided into stages. Referring to FIG. 7, a preform manufactured by a binder jet 3D printing process is prepared. A melt forming step is performed in which a metal material is provided in the first crucible 112 and heated to a first heating temperature set in advance in a first heating region. A preliminary heat treatment step is performed in which the preform is provided in the second crucible 122 and heated to a preset second heating temperature in a second heating region (S710). The first crucible 112 and the second crucible 122 equipped with melt formed by being heated to a first heating temperature set in advance in the first heating region are connected with a connection pipe 172 . The melted material provided in the first crucible 112 is supplied into the second crucible 122 through the connection pipe 172 using gravity (S720). The preform is impregnated (S730).

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

10; Preform impregnation processing device 100; main body
110; 1st heater 112; Crucible No. 1
120; 2nd heater 122; 2nd Crucible
160; pressure pipe 162; cover
170; Opening part 172; connector
200; control unit 300; Elevator
400; vacuum system

Claims (16)

A main body having a guide part that is provided long from the inner center along a first direction set in advance and guides the movement of the corresponding crucible;
A plurality of heat treatment units having different heating temperatures along the first direction around the guide unit, and
Impregnation processing unit that processes drying, pre-heat treatment, and impregnation of the preform supplied to the inside of the guide unit
Preform impregnation processing device comprising a. In paragraph 1,
The heat treatment part
A first heater provided outside the guide portion in a first heating area corresponding to an upper side of the guide portion to heat the first heating area to a preset first heating temperature; and
A second heater provided outside the guide part in the second heating area corresponding to the lower side of the guide part to heat the second heating area to a preset second heating temperature.
Preform impregnation processing device comprising a. In paragraph 2,
The impregnation treatment part
A first crucible provided at a position corresponding to the first heating area inside the guide unit to support the impregnation process of the preform, and
A second crucible provided at a position corresponding to the second heating area inside the guide unit, moved up and down according to external force, and supporting the impregnation process of the preform.
Preform impregnation processing device comprising a. In paragraph 3,
The first heating temperature is lower than the second heating temperature. In paragraph 4,
A preform impregnation processing apparatus in which the preform is provided in the first crucible. In paragraph 5,
Preform impregnation processing apparatus further comprising a driving unit provided on the lower side of the second crucible to implement vertical movement of the second crucible. In paragraph 6,
A preform impregnation processing apparatus in which a melt formed by heating to the second heating temperature is provided in the second crucible, and the second crucible having the melt is raised to impregnate the preform. In paragraph 5,
A cover provided on the upper part of the second crucible, and
A pressure tube connected to the second crucible through the first crucible and the cover
Including more,
A melt formed by being heated to the second heating temperature is provided in the second crucible, pressurizes the melt provided in the second crucible, supplies the melt to the inside of the first crucible through the pressure pipe, and A preform impregnation processing device in which the preform is impregnated. In paragraph 3,
The first heating temperature is higher than the second heating temperature. In paragraph 9,
A preform impregnation processing apparatus in which the preform is provided in the second crucible. In paragraph 10,
A preform impregnation processing apparatus in which a melt formed by heating to the first heating temperature is provided in the first crucible. In paragraph 11,
A connection pipe provided between the first crucible and the second crucible to guide the molten material provided in the first crucible to be supplied to the second crucible, and
A preform impregnation processing apparatus including an opening and closing part provided in the first crucible and opening and closing the connection pipe connected to the first crucible. In paragraph 1,
The preform is a preform impregnation processing device formed by a 3D printing process of a binder jet method. A first crucible that is provided elongated along a first direction set in advance from the inner center and is provided on the upper side of the guide part inside the guide part that guides the movement of the corresponding crucible to support the impregnation process of the preform, and
Drying of the preform supplied to the inside of the guide part by using a preform impregnation treatment apparatus including a second crucible provided on the lower side of the guide part inside the guide part and moving up and down according to an external force to support the impregnation process of the preform; In the preform impregnation treatment method of pre-heat treatment and impregnation process,
Preparing a preform manufactured by the 3D printing process of the binder jet method;
A pre-heat treatment step of heating the preform in the first crucible to a first heating temperature set in advance in a first heating region; and
Impregnation step of impregnating the preform by raising the second crucible equipped with a melted material
Preform impregnation treatment method comprising a. A first crucible that is provided elongated along a first direction set in advance from the inner center and is provided on the upper side of the guide part inside the guide part that guides the movement of the corresponding crucible to support the impregnation process of the preform, and
Drying of the preform supplied to the inside of the guide part by using a preform impregnation treatment apparatus including a second crucible provided on the lower side of the guide part inside the guide part and moving up and down according to an external force to support the impregnation process of the preform; In the preform impregnation treatment method of pre-heat treatment and impregnation process,
Preparing a preform manufactured by the 3D printing process of the binder jet method;
A pre-heat treatment step of heating the preform in the first crucible to a first heating temperature set in advance in a first heating region;
Connecting the second crucible and the first crucible equipped with a melt formed by heating to a second heating temperature set in advance in a second heating region with a pressure pipe, and
An impregnation step of pressurizing the melt provided in the second crucible to supply the melt to the inside of the first crucible through the pressure tube and impregnating the preform.
Preform impregnation treatment method comprising a. A first crucible that is provided elongated along a first direction set in advance from the inner center and is provided on the upper side of the guide part inside the guide part that guides the movement of the corresponding crucible to support the impregnation process of the preform, and
Drying of the preform supplied to the inside of the guide part by using a preform impregnation treatment apparatus including a second crucible provided on the lower side of the guide part inside the guide part and moving up and down according to an external force to support the impregnation process of the preform; In the preform impregnation treatment method of pre-heat treatment and impregnation process,
Preparing a preform manufactured by the 3D printing process of the binder jet method;
A pre-heat treatment step of providing the preform in the second crucible and heating it to a preset second heating temperature in a second heating region;
Connecting the first crucible and the second crucible equipped with a melt formed by heating to a first heating temperature set in advance in a first heating region with a connection pipe, and
An impregnation step of supplying the molten material provided in the first crucible to the inside of the second crucible through the connection pipe using gravity and impregnating the preform.
Preform impregnation treatment method comprising a.

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