CN114353528A

CN114353528A - Multistage pressure rapid sintering furnace and use process thereof

Info

Publication number: CN114353528A
Application number: CN202210037183.9A
Authority: CN
Inventors: 张昱; 吴松; 刘强; 崔成强; 杨冠南; 钟克菊; 曹秀华
Original assignee: Guangdong Fenghua Advanced Tech Holding Co Ltd; Guangdong University of Technology
Current assignee: Guangdong Fenghua Advanced Tech Holding Co Ltd; Guangdong University of Technology
Priority date: 2022-01-13
Filing date: 2022-01-13
Publication date: 2022-04-15
Anticipated expiration: 2042-01-13
Also published as: CN114353528B

Abstract

The invention discloses a multistage pressure rapid sintering furnace and a using process thereof, and relates to the technical field of metallurgy and chip packaging interconnection. The multistage pressure rapid sintering furnace provided by the invention abandons the traditional sintering furnace to use an air extractor to remove air in the furnace, and creatively provides a method for removing air in the sintering furnace in a way of directly introducing hydraulic oil into the sintering furnace through a hydraulic system.

Description

Multistage pressure rapid sintering furnace and use process thereof

Technical Field

The invention relates to the technical field of metallurgy and chip packaging interconnection, in particular to a multistage pressure rapid sintering furnace and a using process thereof.

Background

In the field of chip packaging interconnection, after a layer of nano copper paste is coated between a substrate and a chip by the technologies such as screen printing and the like, the copper paste needs to be sintered again, so that the density and physical properties of a connecting layer of the substrate and the chip are improved, copper paste particles are mutually bonded at high temperature, crystal grains grow up, gaps (air holes) and crystal boundaries gradually decrease, the total volume is shrunk and the density is increased by the transfer of substances, and finally, the copper paste becomes a compact polycrystalline sintered body with a certain microstructure.

Traditional fritting furnace uses air exhaust device to take out the interior air of stove, pressurizes the sample through mechanical pressurization mode, uses air exhaust device not only troublesome, and the process of bleeding moreover causes the diffusion of copper lotion easily, uses mechanical pressurization's mode, can cause the sintering layer fracture, influences sintering performance.

Disclosure of Invention

The invention aims to provide a multistage pressure rapid sintering furnace, which can enable a sample to bear stable pressure by using liquid as a force transmission medium, avoids the damage of a sample sintering layer in a pressurizing process, effectively avoids the diffusion of a copper paste body by exhausting air in the sintering furnace in a hydraulic oil mode, and solves the problems that the copper paste body is easy to diffuse and the sintering layer is broken because an air exhaust device is used for exhausting air in the furnace and mechanical pressurization is used in a traditional sintering furnace.

The invention also aims to provide a using process of the multistage pressure rapid sintering furnace, which has the advantages of simple operation and high sintering efficiency.

A multistage pressure rapid sintering furnace comprises a wall body 1, a clamping device 2, a hydraulic system 3 and a plurality of work tables 4, wherein a cavity 5 is arranged inside the wall body 1, the work tables 4 are arranged in the cavity 5 at intervals in a vertically movable mode, the side surfaces of the work tables 4 and the inner wall of the wall body 1 are arranged in a sealing mode, the work tables 4 divide the cavity 5 into a plurality of hydraulic cavities, the hydraulic cavity at the top of the cavity 5 is a first hydraulic cavity 51, and the hydraulic cavity at the bottom of the cavity 5 is a bottom hydraulic cavity 52;

the clamping device 2 is arranged at the top of the workbench 4, the clamping device 2 is used for fixing the position of the sample 6, and the bottom of the workbench 4 is provided with a heating device 42;

a throttle valve 41 is arranged in the workbench 4 above the workbench 4 at the bottom of the cavity 5, a first working oil port of the hydraulic system 3 is communicated with the first hydraulic cavity 51, and a second working oil port of the hydraulic system 3 is communicated with the bottom hydraulic cavity 52; before sintering, the hydraulic system 3 is used for driving the plurality of the working tables 4 to sequentially move downwards to pressurize the sample 6, and after sintering is completed, the hydraulic system 3 is used for driving the plurality of the working tables 4 to move upwards to realize pressure relief;

when pressurizing sample 6, the hydraulic oil input from hydraulic system 3 passes through choke valve 41, gets into a plurality ofly in proper order the hydraulic pressure chamber, and makes a plurality ofly the pressure in hydraulic pressure chamber is from last to descending in proper order.

Further, the multistage pressure rapid sintering furnace comprises four work tables 4, the four work tables 4 are arranged in the cavity 5 at intervals, from top to bottom, the four work tables 4 are respectively a first work table, a second work table, a third work table and a fourth work table, the four work tables 4 divide the cavity 5 into five hydraulic cavities, and from top to bottom, the five hydraulic cavities are respectively a first hydraulic cavity 51, a second hydraulic cavity 53, a third hydraulic cavity 54, a fourth hydraulic cavity 55 and a bottom hydraulic cavity 52;

all be equipped with choke valve 41 in first workstation, second workstation, the third workstation, do not be equipped with choke valve 41 in the fourth workstation.

Further, the hydraulic system 3 includes a reversing valve 31, a hydraulic pump 32, an oil tank 34, an oil inlet pipeline 37 and an oil return pipeline 38, one end of the oil inlet pipeline 37 is communicated with the oil outlet end of the oil tank 34, the other end of the oil inlet pipeline 37 is communicated with the oil inlet end of the reversing valve 31, one end of the oil return pipeline 38 is communicated with the oil outlet end of the reversing valve 31, the other end of the oil return pipeline 38 is communicated with the oil inlet end of the oil tank 34, and the hydraulic pump 32 is connected to the oil inlet pipeline 37 in parallel;

the oil inlet pipeline 37 is provided with an overflow valve 36, and the oil return pipeline 38 is provided with a back pressure valve 33;

the direction valve 31 includes a right operation position 311 and a left operation position 312, the right operation position 311 is communicated with the first hydraulic chamber 51, and the left operation position 312 is communicated with the bottom hydraulic chamber 52.

Further, a first cavity oil port 11 is arranged at the top of the wall body 1, a second cavity oil port 12 is arranged at the bottom of the wall body 1, a right working position 311 of the reversing valve 31 is communicated with the first cavity oil port 11, and a left working position 312 of the reversing valve 31 is communicated with the second cavity oil port 12;

and a pressure monitoring device 35 is arranged between the first cavity oil port 11 and the reversing valve 31.

Further, the clamping device 2 comprises a base 21, a pressing plate 22 and a vertical guide rail 23, wherein the base 21 is mounted on the worktable 4, and the base 21 is used for placing the sample 6;

the vertical guide rail 23 is vertically installed on the top surface of the base 21, the top of the vertical guide rail 23 passes through the pressing plate 22, the pressing plate 22 is installed above the base 21 through the vertical guide rail 23, and the pressing plate 22 is used for fixing the longitudinal position of the sample.

Further, the clamping device 2 further comprises two horizontal guide rails 24, two limiting plates 25 and two adjusting screws 26, the two limiting plates 25 are respectively located on the left side and the right side of the top of the base 21, the two horizontal guide rails 24 are located on the front side and the rear side of the top of the base 21, the horizontal guide rail 24 located on the front side sequentially penetrates through the front ends of the two limiting plates 25, and the horizontal guide rail 24 located on the rear side sequentially penetrates through the rear ends of the two limiting plates 25;

the two adjusting screws 26 are respectively located on the front side and the rear side of the top of the base 21, the adjusting screws 26 sequentially penetrate through the two limiting plates 25 and are parallel to the horizontal guide rail 24, and the two limiting plates 25 are used for fixing the horizontal position of the sample 6.

Further, a fixing part 211 protruding downwards is arranged at the bottom of the base 21, an installation groove 43 matched with the fixing part 211 is arranged in the middle of the workbench 4, and the fixing part 211 is installed in the installation groove 43;

the middle part of the working table 4 is provided with a boss 44 protruding downwards, and the heating device 42 is arranged around the periphery of the boss 44.

Further, the multistage pressure rapid sintering furnace further comprises a guide device 7, the guide device 7 is vertically arranged in the cavity 5, the guide device 7 comprises a guide rod 71 and a plurality of springs 72, the guide rod 71 sequentially penetrates through the plurality of work tables 4, the top of the guide rod 71 is mounted at the top of the wall body 1, and the bottom of the guide rod 71 is mounted at the bottom of the wall body 1;

the springs 72 are respectively sleeved outside the guide rods 71, one ends of the springs are fixedly connected with the wall body, and the other ends of the springs are fixedly connected with the working tables 4, or the springs are fixedly connected between two adjacent working tables.

Further, the wall body 1 is composed of a plurality of heat insulation layers, and the plurality of heat insulation layers are respectively made of any one of a carbonaceous heat insulation material, a composite heat insulation material and an aerogel heat insulation material.

A using process of a multi-stage pressure rapid sintering furnace is applied to the multi-stage pressure rapid sintering furnace and comprises the following steps:

(1) selecting the number of the working tables, and fixing the clamping device with the sample on the working tables;

(2) pressurizing the sample, and maintaining the pressure of the sample after the pressure reaches the required pressure of the sample;

(3) the sample is calcined while maintaining pressure, and the calcining process comprises the following three stages:

the first stage is as follows: heating the sintering furnace to 75-85 ℃, and keeping the temperature for 2-8 min;

and a second stage: heating the sintering furnace to 145-155 ℃, and preserving heat for 7-13 min;

and a third stage: heating the sintering furnace to 190 ℃ and 210 ℃, and preserving heat for 25-35 min;

(4) and after sintering, decompressing the sample, and taking out the sample to obtain a finished product.

One of the above technical solutions has the following beneficial effects: the multistage pressure rapid sintering furnace of the technical scheme abandons the traditional sintering furnace to use an air extractor to extract air in the furnace, innovatively provides a method for directly removing air in the sintering furnace through a hydraulic system in a mode of introducing hydraulic oil into the sintering furnace, not only can a sample bear stable pressure by using liquid (hydraulic oil) as a force conduction medium, avoids the damage of a sample sintering layer in a pressurizing process, the heat conductivity of the liquid is far greater than that of gas, the rapid temperature rise in the furnace can be realized, and a plurality of work tables can be flexibly placed in the multistage pressure rapid sintering furnace of the technical scheme, thereby realizing sintering of a plurality of samples simultaneously, and through a throttle valve, the pressure of a plurality of hydraulic cavities can be sequentially decreased from top to bottom, thereby realizing the rapid sintering of the multistage pressure of the samples with different pressure requirements.

Drawings

FIG. 1 is a schematic structural view of a multi-stage pressure rapid sintering furnace according to an embodiment of the present invention;

FIG. 2 is a diagram of the multi-stage pressure rapid sintering furnace of FIG. 1 in operation to pressurize a sample;

FIG. 3 is a bottom view of the table 4 shown in FIG. 1;

FIG. 4 is a schematic view of the structure of the clamping device shown in FIG. 1;

FIG. 5 is a top view of the clamping device of FIG. 4 with the pressure plate removed;

wherein: the wall body 1, the clamping device 2, the hydraulic system 3, the workbench 4, the cavity 5, the sample 6, the guiding device 7, the temperature monitoring device 8, the first cavity oil port 11, the second cavity oil port 12, the base 21, the pressing plate 22, the vertical guide rail 23, the horizontal guide rail 24, the limiting plate 25, the adjusting screw 26, the reversing valve 31, the hydraulic pump 32, the back pressure valve 33, the oil tank 34, the pressure monitoring device 35, the overflow valve 36, the oil inlet pipeline 37, the oil return pipeline 38, the throttle valve 41, the heating device 42, the mounting groove 43, the boss 44, the first hydraulic cavity 51, the bottom hydraulic cavity 52, the second hydraulic cavity 53, the third hydraulic cavity 54, the fourth hydraulic cavity 55, the guide rod 71, the spring 72 and the fixing part 211.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. Furthermore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features for distinguishing between descriptive features, non-sequential, non-trivial and non-trivial.

In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

A multistage pressure rapid sintering furnace and a process using the same according to an embodiment of the present invention will be described with reference to fig. 1 to 5.

A multistage pressure rapid sintering furnace comprises a wall body 1, a clamping device 2, a hydraulic system 3 and a plurality of work tables 4, wherein a cavity 5 is arranged inside the wall body 1, the work tables 4 are arranged in the cavity 5 at intervals in a vertically movable mode, the side faces of the work tables 4 and the inner wall of the wall body 1 are arranged in a sealing mode, the work tables 4 divide the cavity 5 into a plurality of hydraulic cavities, the hydraulic cavity on the top of the cavity 5 is a first hydraulic cavity 51, and the hydraulic cavity on the bottom of the cavity 5 is a bottom hydraulic cavity 52;

a throttle valve 41 is arranged in the workbench 4 above the workbench 4 at the bottom of the cavity 5, a first working oil port of the hydraulic system 3 is communicated with a first hydraulic cavity 51, and a second working oil port of the hydraulic system 3 is communicated with a bottom hydraulic cavity 52; before sintering, the hydraulic system 3 is used for driving the plurality of work tables 4 to sequentially move downwards to pressurize the sample 6, and after sintering is completed, the hydraulic system 3 is used for driving the plurality of work tables 4 to move upwards to realize pressure relief;

when the sample 6 is pressurized, the hydraulic oil input from the hydraulic system 3 sequentially enters the plurality of hydraulic chambers through the throttle valve 41, and the pressures of the plurality of hydraulic chambers are sequentially decreased from top to bottom.

The air in the existing traditional sintering furnace is usually pumped by using an air pumping device, and the sample is pressurized by a mechanical pressurization mode, so that the use of the air pumping device is not only troublesome, but also the diffusion of copper paste is easily caused in the air pumping process, and the sintering layer can be broken by using the mechanical pressurization mode, thereby influencing the sintering performance.

The multi-stage pressure rapid sintering furnace (hereinafter referred to as sintering furnace) of the technical scheme abandons the traditional sintering furnace that an air extractor is used for extracting the air in the furnace, and creatively provides a method for removing the air in the sintering furnace by directly introducing hydraulic oil into the sintering furnace through a hydraulic system 3, the technical scheme can ensure that a sample 6 bears stable pressure by using liquid (hydraulic oil) as a force transmission medium, avoids the damage of a sintering layer of the sample 6 in the pressurizing process, the heat conductivity of the liquid is far greater than that of the gas, the rapid temperature rise in the furnace can be realized, and the multistage pressure rapid sintering furnace of the technical scheme can flexibly place a plurality of work tables 4, thereby realize sintering a plurality of samples 6 simultaneously to the pressure that enables a plurality of hydraulic pressure chambeies through choke valve 41 is from last to descending in proper order, thereby has realized carrying out multistage pressure to the many samples of different pressure demands and has sintered fast.

Specifically, before pressurization, hydraulic oil is introduced into the bottom hydraulic chamber 52 through the hydraulic system, gas in the bottom hydraulic chamber 52 is removed, pressurization is performed, the hydraulic oil enters the first hydraulic chamber 51 from the first working oil port of the hydraulic system 3 through the hydraulic system at a pressure P1, enters the next hydraulic chamber through the throttle valve 41 on the top workbench 4, sequentially enters the rest hydraulic chambers through the throttle valves 41 on the rest workbenches 4, until the hydraulic oil flows into the hydraulic chamber adjacent to the bottom hydraulic chamber 52, as the hydraulic oil in the first hydraulic chamber 51 increases, the multiple workbenches 4 sequentially move downward, and as the throttle valves 41 are not arranged in the workbenches 4 at the bottom of the cavity 5, the hydraulic oil in the bottom hydraulic chamber 52 flows back into the hydraulic system 3 through the second working oil port of the hydraulic system 3, when hydraulic oil flows through the throttling valve on the workbench 4, a pressure drop is formed, so that the pressure of the multiple hydraulic cavities is gradually reduced from the first hydraulic cavity 51 to the bottom hydraulic cavity 52, the multiple workbenches 4 sequentially move downwards, the multiple samples 6 are respectively pressurized, the areas of the valve ports of the throttling valves in the different workbenches can be controlled in a grading manner, the pressure born by each sample 6 is further controlled, and the rapid multistage pressure sintering of the multiple samples with different pressure requirements is realized. When the pressure reaches the pressure requirement of the sample 6, the continuous transmission of the hydraulic oil into the first hydraulic cavity 51 is stopped, and the backflow of the hydraulic oil is avoided, so that the pressure borne by the multiple samples 6 is kept unchanged, the heating device 42 is started, the sintering furnace is heated, and the samples are sintered. After sintering, hydraulic oil enters the bottom hydraulic cavity 52 from the second working oil port of the hydraulic system 3, and drives the plurality of work tables to move upwards in sequence, so that the hydraulic oil in the hydraulic cavity flows back to the hydraulic system 3 from the first hydraulic cavity 51, and pressure relief is achieved.

Specifically, the flow area and the shape of the throttle valves 41 are controllable, and since the side surfaces of the working table 4 and the inner wall of the wall body 1 are hermetically arranged, hydraulic oil can only enter the next hydraulic cavity through the plurality of throttle valves 41 (except the working table 4 at the bottom of the cavity 5), so that multi-stage pressure transmission is realized.

Preferably, four throttle valves 41 are arranged in the rest of the plurality of work tables 4 except the work table 4 located at the bottom of the chamber 5, and the four throttle valves 41 are uniformly distributed in the work table 4.

Preferably, the outer edge of the table 4 is fitted with a sealing sleeve, so that the side of the table 4 and the inner wall of the wall 1 are sealingly arranged.

Preferably, the hydraulic oil is any one of liquid sodium chloride, linseed oil and ethylene glycol phenyl ether.

It is worth explaining that liquid sodium chloride, linseed oil and ethylene glycol phenyl ether are the liquid that the boiling point is high, after hydraulic oil is carried into cavity 5, make in the cavity 5 be vacuum state, and surrounded by hydraulic oil around the sample 6, when the sintering, can rapid heating sample 6, this technical scheme not only can make sample 6 bear steady pressure as power conduction medium through hydraulic oil, avoid the sintering bed of sample 6 to be destroyed in the pressurization process, and the thermal conductivity of liquid is greater than gaseous far away, can realize cavity 5 rapid heating up.

Further, the multistage pressure rapid sintering furnace comprises four work tables 4, the four work tables 4 are arranged in the cavity 5 at intervals, the four work tables 4 are respectively a first work table, a second work table, a third work table and a fourth work table from top to bottom, the cavity 5 is divided into five hydraulic cavities by the four work tables 4, and the five hydraulic cavities are respectively a first hydraulic cavity 51, a second hydraulic cavity 53, a third hydraulic cavity 54, a fourth hydraulic cavity 55 and a bottom hydraulic cavity 52 from top to bottom;

the first workbench, the second workbench and the third workbench are all provided with a throttle valve 41, and the fourth workbench is not provided with a throttle valve 41.

In the technical scheme, the four work tables 4 are arranged, the cavity 5 is divided into five hydraulic cavities by the four work tables 4, the second worktable, the third worktable and the fourth worktable are respectively provided with a clamping device 2 for placing a sample 6, due to the action of the throttle valve 41, the pressure of the first hydraulic chamber 51 > the pressure of the second hydraulic chamber 53 > the pressure of the third hydraulic chamber 54 > the pressure of the fourth hydraulic chamber 55 > the pressure of the bottom hydraulic chamber 52, so that three samples 6 can be pressurized at the same time, when the pressure reaches the pressure required by the samples, the pressure in the five hydraulic cavities is constant through the hydraulic system 3, the heating device 42 is started to heat, thereby sintering the sample, this technical scheme can heat and sinter three sample 6 simultaneously through four workstation 4, has strengthened the efficiency of sintering greatly, can realize carrying out multistage pressure quick sintering to the many samples of different pressure demands moreover.

To further illustrate, the hydraulic system 3 includes a reversing valve 31, a hydraulic pump 32, an oil tank 34, an oil inlet pipeline 37 and an oil return pipeline 38, one end of the oil inlet pipeline 37 is communicated with the oil outlet end of the oil tank 34, the other end of the oil inlet pipeline 37 is communicated with the oil inlet end of the reversing valve 31, one end of the oil return pipeline 38 is communicated with the oil outlet end of the reversing valve 31, the other end of the oil return pipeline 38 is communicated with the oil inlet end of the oil tank 34, and the hydraulic pump 32 is connected to the oil inlet pipeline 37 in parallel;

To be further described, the top of the wall body 1 is provided with a first cavity oil port 11, the bottom of the wall body 1 is provided with a second cavity oil port 12, the right working position 311 of the reversing valve 31 is communicated with the first cavity oil port 11, and the left working position 312 of the reversing valve 31 is communicated with the second cavity oil port 12;

a pressure monitoring device 35 is arranged between the first cavity oil port 11 and the reversing valve 31.

Specifically, the hydraulic pump 32 is a power element of the entire hydraulic system 3, and supplies a pressure P1, and the pressure of the first hydraulic chamber 51 is equal to P1, and the pressure of the second hydraulic chamber 53 is set to P2, the pressure of the third hydraulic chamber 54 is set to P3, the pressure of the fourth hydraulic chamber 55 is set to P4, and the pressure of the bottom hydraulic chamber 52 is set to P5. When the electromagnet at the right end of the reversing valve 31 is energized, hydraulic oil sequentially passes through the right working position of the reversing valve 31, the first cavity oil port 11, the first hydraulic cavity 51, the throttle valve 41 on the first workbench 42, the second hydraulic cavity 53, the throttle valves 41 on the second workbench 43 and the third workbench 44 from the oil tank 34, and finally flows into the fourth hydraulic cavity 55, the first workbench 42, the second workbench 43 and the third workbench 44 move downwards due to continuous input of the hydraulic oil, so that the bottom hydraulic cavity 52 is pushed to move downwards, and the hydraulic oil in the bottom hydraulic cavity 52 finally flows back to the oil tank 34 through the second cavity oil port 12, the reversing valve 31 and the back pressure valve 33. Due to the action of the throttle valve, when the hydraulic oil flows through the throttle valve on the worktable, a pressure drop is formed, namely the pressure P1 of the first hydraulic pressure chamber 51 is greater than the pressure P2 of the second hydraulic pressure chamber 53, so that the first worktable 42 moves downwards, and the pressure applied to the sample in the second hydraulic pressure chamber 53 is (P1-P2) multiplied by A, wherein A is the area of the top surface of the worktable. By analogy, the sample 6 in the third hydraulic chamber 54 is subjected to a pressure of (P2-P3) × a, and the sample 6 in the fourth hydraulic chamber 55 is subjected to a force of (P3-P4) × a. Flow of hydraulic oilThe pressure drop across the valve port of each throttle valve is Δ P ═ q/k × a^1/mWherein q is flow, k is a throttling coefficient, a is the flow area of an air interface or a gap, and m is an index. The valve port area of the throttle valve in the workbench can be controlled in a grading manner, so that the pressure born by each sample can be controlled. When the electromagnetic pilot valve of the reversing valve 31 is not powered, the valve core is in the middle position, oil chambers at two ends of the valve core are simultaneously communicated with the oil tank, and the pressure borne by the sample is unchanged. When the electromagnet at the left end of the reversing valve is electrified, hydraulic oil enters the bottom hydraulic cavity 52 from the oil tank 34 through the left working position of the reversing valve 31, the fourth workbench is driven to move upwards in sequence, and the hydraulic oil flows back to the oil tank 34 through the first hydraulic cavity 51, the reversing valve 31 and the back pressure valve 33 in sequence to realize pressure relief.

It should be noted that the oil return line 38 is provided with a back pressure valve 33, which can maintain a constant pressure at the output end of the hydraulic pump 32 to prevent the hydraulic oil from flowing back; the oil inlet pipeline 37 is provided with an overflow valve 36 which can play a role of safety protection and can release pressure when the system pressure exceeds a set value.

Preferably, the reversing valve 31 is a three-position four-way electro-hydraulic reversing valve, and the reversing valve 31 is any one of an M-type reversing valve, an H-type reversing valve and a K-type reversing valve;

preferably, the hydraulic pump 32 is any one of a plunger pump, a vane pump, a gear pump and a screw pump;

specifically, the pressure of the hydraulic oil entering the first hydraulic chamber 51 can be monitored by providing the pressure monitoring device 35 between the first chamber oil port 11 and the selector valve 31.

Preferably, the pressure monitoring device 35 is a pressure gauge.

Preferably, the first cavity oil port 11 and the second cavity oil port 12 are internally provided with sealing devices to prevent oil leakage, and the sealing devices are rubber rings.

To illustrate further, the holding device 2 comprises a base 21, a pressing plate 22 and a vertical guide rail 23, wherein the base 21 is installed on the worktable 4, and the base 21 is used for placing the sample 6;

Further, the clamping device 2 further includes two horizontal guide rails 24, two limiting plates 25 and two adjusting screws 26, the two limiting plates 25 are respectively located at the left and right sides of the top of the base 21, the two horizontal guide rails 24 are located at the front and rear sides of the top of the base 21, the horizontal guide rail 24 located at the front side sequentially passes through the front ends of the two limiting plates 25, and the horizontal guide rail 24 located at the rear side sequentially passes through the rear ends of the two limiting plates 25;

the two adjusting screws 26 are respectively positioned at the front side and the rear side of the top of the base 21, the adjusting screws 26 sequentially penetrate through the two limiting plates 25 and are parallel to the horizontal guide rail 24, and the two limiting plates 25 are used for fixing the horizontal position of the sample 6.

It should be noted that, before the sample 6, the sample 6 is placed on the top of the base 21, the nut on the screw is tightened, the two limit plates 25 are moved toward the middle, the sample 6 is sandwiched between the two limit plates 25, thereby fixing the horizontal direction of the sample 6, and then the pressing plate 22 is mounted on the vertical guide rail 23, and the longitudinal position of the sample 6 is fixed by the gravity of the pressing plate 22. Through the clamping device 2 of the technical scheme, samples in various shapes can be fixed, the displacement of the samples in the sintering process is prevented, and therefore better pressurizing and sintering effects can be achieved.

Preferably, the length of the vertical guide 23 is adjustable according to the height of the sample 6, and the guide may be provided in a plurality of sections, each of which is connected by a screw.

To be further described, the bottom of the base 21 is provided with a fixing portion 211 protruding downwards, the middle of the worktable 4 is provided with a mounting groove 43 matched with the fixing portion 211, and the fixing portion 211 is mounted in the mounting groove 43;

It should be noted that, the mounting groove 43 is provided in the worktable 4, so that the fixing portion 211 is detachably mounted on the worktable 4, thereby fixing the clamping device 2 and preventing the clamping device 2 from loosening or displacing, and the boss 44 is provided at the bottom of the worktable 4 and located above the adjacent pressing plate 22, when the sample 6 is pressurized, as the worktable 4 moves downward, the boss 44 applies downward pressure to the top of the pressing plate 22, thereby improving the pressurizing effect.

Preferably, the heating device 42 is a resistance wire or a heating plate.

Preferably, a temperature monitoring device 8 is arranged in the cavity 5, and the temperature of the cavity 5 is monitored through the temperature monitoring device 8, so that the sintering effect can be better ensured.

Preferably, the temperature monitoring device 8 is a temperature sensor.

the plurality of springs 72 are respectively sleeved outside the guide rod 71, one end of each spring is fixedly connected with the wall body, and the other end of each spring is fixedly connected with the workbench 4, or the springs are fixedly connected between two adjacent workbenches.

It is worth to say that, a circular hole for the guide rod 71 to pass through is arranged in the workbench 4, so that the workbench 4 can move up and down along the guide rod 71, and the plurality of workbenches 4 are respectively supported by the plurality of springs 72, thereby realizing multi-stage pressure transmission, and further realizing pressurization or pressure relief of the sample 6.

Specifically, when the number of the working tables is four, the number of the springs is five, one end of each spring positioned at the top of the guide rod 7 is fixedly connected with the top of the wall body, and the other end of each spring is fixedly connected with the top surface of the first working table; one end of a spring positioned at the bottom of the guide rod 7 is fixedly connected with the bottom of the wall body, the other end of the spring is fixedly connected with the bottom of the fourth workbench, and the rest three springs are fixedly connected between the two adjacent workbenches.

Preferably, guider 7 is equipped with two, and two guider 7 are located the left and right sides of workstation 4 respectively, through setting up two guider 7, when first hydraulic pressure chamber 51 pressure constantly increases, can drive the firm reciprocating of a plurality of workstations 4 along two guide arms 71, supports the bottom of wall body 1 until being located the workstation 4 of lowest portion.

Further, the wall body 1 is composed of multiple insulation layers, and the multiple insulation layers are made of any one of a carbonaceous thermal insulation material, a composite thermal insulation material and an aerogel thermal insulation material.

It is worth explaining that the heat preservation and heat insulation effect of the wall body 1 can be enhanced by arranging the multiple heat preservation layers, and heat leakage of a sintering furnace is avoided, so that the sintering effect is better, and meanwhile, the energy consumption can be saved.

Preferably, the wall body 1 consists of three heat-insulating layers from outside to inside, the three heat-insulating layers are a first heat-insulating layer, a second heat-insulating layer and a third heat-insulating layer respectively, the first heat-insulating layer is made of carbonaceous heat-insulating materials, the second heat-insulating layer is made of composite heat-insulating materials, and the third heat-insulating layer is made of carbonaceous heat-insulating materials. Specifically, the carbonaceous heat-insulating material, the composite heat-insulating material and the aerogel heat-insulating material can be directly purchased from the market.

Preferably, the aerogel thermal insulation material is silica aerogel, the carbonaceous thermal insulation material is a carbon silica plate, and the composite thermal insulation material is a cement-based silica aerogel-diatomite composite thermal insulation material.

Specifically, the use process of the multistage pressure rapid sintering furnace comprises the following steps:

(1) preparing and setting out: the method comprises the following steps of taking a large copper plate as a substrate and a small copper plate as a simulation chip, coating a layer of copper paste on the large copper plate by means of screen printing and the like, placing a small copper plate on the upper layer of the copper paste to form a sandwich structure sample of substrate-copper paste-simulation chip, selecting the number of a workbench, screwing nuts on adjusting screws on a clamping device, fixing the horizontal direction of the sample through a limiting plate, fixing the Z-axis direction of the sample by utilizing the gravity of a pressing plate, and finally fixing the clamping device in a mounting groove of the workbench;

(2) pressurizing and maintaining pressure: starting a hydraulic pump, setting the pressure of an overflow valve and a back pressure valve, enabling a reversing valve to work at a right working position, enabling hydraulic oil to flow into a cavity from a first cavity oil port 11 at the top of the sintering furnace, moving a workbench downwards under the action of the pressure, and pressurizing a sample;

(3) pressure maintaining and heating: enabling the reversing valve to work at the middle working position, maintaining the pressure of the sample, starting heating at the same time, heating the sintering furnace to 75-85 ℃ in the first heating stage, and preserving the heat for 2-8 min; in the second stage, the temperature of the sintering furnace is raised to 145-155 ℃, and the temperature is kept for 7-13 min; in the third stage, the temperature of the sintering furnace is raised to 190-;

(4) pressure relief and sampling: and (3) enabling the reversing valve to work at a left working position, enabling the hydraulic oil to flow back to the oil tank 34 from the first cavity oil port 11 at the top of the sintering furnace, realizing pressure relief, dismounting the die, and taking out the sample to obtain a finished product.

It is worth explaining that the use process of the multistage pressure rapid sintering furnace adopting the technical scheme is simple to operate, high in sintering efficiency and easy to realize industrial production.

The technical solution of the present invention is further illustrated by the following examples.

A multistage pressure rapid sintering furnace comprises a wall body 1, a clamping device 2, a hydraulic system 3, a workbench 4, a cavity 5 and a guide device 7, wherein the hydraulic system 3 consists of a reversing valve 31, a hydraulic pump 32, a back pressure valve 33, an oil tank 34, a pressure monitoring device 35, an overflow valve 36, an oil inlet pipeline 37 and an oil return pipeline 38, the wall body 1 is filled with three layers of heat insulation materials, a first heat insulation layer is a carbon heat insulation material, a second heat insulation layer is a composite heat insulation material, and a third heat insulation layer is a carbon heat insulation material, wherein the workbench 4 is provided with four layers to realize three-level pressure transmission, the four workbench 4 are respectively a first workbench, a second workbench, a third workbench and a fourth workbench from top to bottom, the first workbench, the second workbench and the third workbench are respectively provided with four throttle valves 41 to adjust the valve port sizes of the throttle valves 41, the pressure of the hydraulic oil is reduced by 3MPa through the first workbench, 2MPa through the second workbench and 1MPa through the third workbench. Wherein, the used hydraulic oil is linseed oil, the hydraulic pump 32 is a gear pump, the reversing valve 31 is of an M type, and the overflow valve 36 is a guide type overflow valve.

The use process of the multistage pressure rapid sintering furnace comprises the following steps: a layer of copper paste is coated on a large copper plate with the thickness of 10mm multiplied by 10mm, and then a small copper plate with the thickness of 3mm multiplied by 3mm is placed on the upper layer of the copper paste to form a sandwich structure sample of the large copper plate-the copper paste-the small copper plate. The sample is placed into the clamping device 2, the nut on the adjusting screw rod of the clamping device 2 is screwed, the horizontal direction of the sample is fixed through the limiting plate 25, then the pressing plate 22 is placed, the Z-axis direction of the sample is fixed by the gravity of the pressing plate 22, and finally the clamping device 2 is fixed in the groove of the workbench. And starting the hydraulic pump 32, setting the pressure of an overflow valve to be 10MPa, setting the pressure of the backpressure valve 33 to be 0.1MPa, enabling the reversing valve 31 to work at a right working position, enabling hydraulic oil to flow into the inner cavity from the first cavity oil port 11 at the top of the sintering furnace, enabling the workbench to move downwards under the action of the pressure, and pressurizing the sample in a grading manner. When the pressure gauge of the first chamber oil port 11 indicates that the pressure is 9MPa, i.e., P1 is 9MPa, P2 is 6MPa, P3 is 4MPa, and P4 is 3MPa, the reversing valve 31 is operated at the intermediate operating position, and the sample is pressurized and heated. In the first stage of heating, the temperature of the sintering furnace is rapidly raised to 80 ℃, the temperature is preserved for 5 minutes, in the second stage, the temperature of the sintering furnace is rapidly raised to 150 ℃, the temperature is preserved for 10 minutes, in the third stage, the temperature of the sintering furnace is rapidly raised to 200 ℃, and the temperature is preserved for 30 minutes. After sintering, the reversing valve 31 is operated at the left working position, and hydraulic oil flows back to the oil tank 34 from the first cavity oil port 11 at the top of the sintering furnace, so that pressure relief is realized. After the furnace is cooled, the holding device 2 is removed and the sample is taken out. Sintering shows that the density, conductivity and shear resistance of the sintered layer are greatly improved relative to sintering in a gas environment.

Other configurations and operations of a multi-stage pressure rapid sintering furnace and processes for using the same according to embodiments of the present invention are known to those of ordinary skill in the art and will not be described in detail herein.

In the description herein, references to the description of the terms "embodiment," "example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A multistage pressure rapid sintering furnace is characterized by comprising a wall body, a clamping device, a hydraulic system and a plurality of working tables, wherein a cavity is arranged inside the wall body, the working tables are arranged in the cavity at intervals in a vertically movable manner, and the side surfaces of the working tables and the inner wall of the wall body are arranged in a sealing manner, so that the cavity is divided into a plurality of hydraulic cavities by the working tables, the hydraulic cavity positioned at the top of the cavity is a first hydraulic cavity, and the hydraulic cavity positioned at the bottom of the cavity is a bottom hydraulic cavity;

the clamping device is arranged at the top of the workbench and used for fixing the position of a sample, and a heating device is arranged at the bottom of the workbench;

a throttling valve is arranged in the workbench above the workbench at the bottom of the cavity, a first working oil port of the hydraulic system is communicated with the first hydraulic cavity, and a second working oil port of the hydraulic system is communicated with the bottom hydraulic cavity; before sintering, the hydraulic system is used for driving the plurality of the working tables to move downwards in sequence to pressurize a sample, and after sintering is completed, the hydraulic system is used for driving the plurality of the working tables to move upwards to realize pressure relief;

when pressurizeing the sample, pass through from the hydraulic oil of hydraulic system input the choke valve gets into a plurality ofly in proper order the hydraulic pressure chamber, and make a plurality ofly the pressure in hydraulic pressure chamber is from last to descending in proper order.

2. The multi-stage pressure rapid sintering furnace according to claim 1, comprising four work tables, wherein the four work tables are arranged in the cavity at intervals, from top to bottom, the four work tables are respectively a first work table, a second work table, a third work table and a fourth work table, the four work tables divide the cavity into five hydraulic chambers, and from top to bottom, the five hydraulic chambers are respectively a first hydraulic chamber, a second hydraulic chamber, a third hydraulic chamber, a fourth hydraulic chamber and a bottom hydraulic chamber;

all be equipped with the choke valve in first workstation, second workstation, the third workstation, not be equipped with the choke valve in the fourth workstation.

3. The multistage pressure rapid sintering furnace according to claim 2, wherein the hydraulic system comprises a reversing valve, a hydraulic pump, an oil tank, an oil inlet pipeline and an oil return pipeline, one end of the oil inlet pipeline is communicated with the oil outlet end of the oil tank, the other end of the oil inlet pipeline is communicated with the oil inlet end of the reversing valve, one end of the oil return pipeline is communicated with the oil outlet end of the reversing valve, the other end of the oil return pipeline is communicated with the oil inlet end of the oil tank, and the hydraulic pump is connected to the oil inlet pipeline in parallel;

the oil inlet pipeline is provided with an overflow valve, and the oil return pipeline is provided with a back pressure valve;

the reversing valve comprises a right working position and a left working position, the right working position is communicated with the first hydraulic cavity, and the left working position is communicated with the bottom hydraulic cavity.

4. The multistage pressure rapid sintering furnace according to claim 3, wherein a first cavity oil port is formed in the top of the wall body, a second cavity oil port is formed in the bottom of the wall body, the right working position of the reversing valve is communicated with the first cavity oil port, and the left working position of the reversing valve is communicated with the second cavity oil port;

and a pressure monitoring device is arranged between the first cavity oil port and the reversing valve.

5. The multi-stage pressure rapid sintering furnace according to claim 1, wherein the clamping device comprises a base, a pressure plate and a vertical guide rail, the base is mounted on the worktable, and the base is used for placing a sample;

the vertical guide rail is vertically arranged on the top surface of the base, the top of the vertical guide rail penetrates through the pressing plate, the pressing plate is arranged above the base through the vertical guide rail, and the pressing plate is used for fixing the longitudinal position of the sample.

6. The multistage pressure rapid sintering furnace according to claim 5, wherein the clamping device further comprises two horizontal guide rails, two limiting plates and two adjusting screws, the two limiting plates are respectively positioned at the left side and the right side of the top of the base, the two horizontal guide rails are positioned at the front side and the rear side of the top of the base, the horizontal guide rail positioned at the front side sequentially penetrates through the front ends of the two limiting plates, and the horizontal guide rail positioned at the rear side sequentially penetrates through the rear ends of the two limiting plates;

the two adjusting screws are respectively positioned on the front side and the rear side of the top of the base, the adjusting screws sequentially penetrate through the two limiting plates and are parallel to the horizontal guide rail, and the two limiting plates are used for fixing the horizontal position of the sample.

7. The multi-stage pressure rapid sintering furnace according to claim 6, wherein the bottom of the base is provided with a fixing part which protrudes downwards, the middle part of the worktable is provided with a mounting groove matched with the fixing part, and the fixing part is mounted in the mounting groove;

the middle part of workstation is equipped with downward bellied boss, heating device encloses to be located the periphery of boss.

8. The multi-stage pressure rapid sintering furnace according to claim 1, further comprising a guide device vertically disposed in the cavity, wherein the guide device comprises a guide rod and a plurality of springs, the guide rod sequentially passes through the plurality of work tables, the top of the guide rod is mounted on the top of the wall body, and the bottom of the guide rod is mounted on the bottom of the wall body;

the springs are sleeved outside the guide rod respectively, one ends of the springs are fixedly connected with the wall body, and the other ends of the springs are fixedly connected with the working tables, or the springs are fixedly connected between the two adjacent working tables.

9. The multi-stage pressure rapid sintering furnace according to claim 1, wherein the wall body is composed of a plurality of insulating layers, and the insulating layers are respectively made of any one of carbonaceous heat insulating material, composite heat insulating material and aerogel heat insulating material.

10. Use process of a multi-stage pressure rapid sintering furnace, characterized in that it is applied to the multi-stage pressure rapid sintering furnace according to any of the claims 1-9, comprising the following steps: