Zirconia denture microwave rapid sintering equipment and process

Abstract

The application discloses a kind of zirconium oxide denture microwave rapid sintering equipment and process, including sealed furnace shell, heat preservation structure, rapid cooling mechanism, microwave auxiliary heating structure, microwave generator, electric control system;The sealed furnace shell is the cuboid of non-magnetic metal material, one of which is microwave feed-in face, one is furnace door, the rest is non-microwave feed-in face, the microwave feed-in face is provided with several microwave feed-in ports;The technical scheme of the present application combines the advantages of rapid heating, synchronous heating of microwave heating characteristics, on the basis of conventional microwave sintering equipment, microwave auxiliary heating structure and rapid cooling mechanism are added;Microwave auxiliary heating structure ensures that zirconium oxide ceramic material can be rapidly heated under low temperature (below 300 DEG C) condition, and further increases the uniformity of heating, greatly improves the heating efficiency;Rapid cooling mechanism can rapidly cool and cooling rate can be controlled.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave sintering, and particularly relates to a zirconia denture microwave rapid sintering equipment and process. BACKGROUND

[0002] Zirconia material has unique stress phase change toughening ability and high flexural strength, and in combination with CAD / CAM technology, zirconia denture has become the mainstream of current oral repair. However, the sintering temperature and sintering time of such zirconia full ceramic material are much higher than those of other dental materials, and generally, a sintering temperature of more than 1400 DEG C and a sintering time of more than 10 hours are required to achieve high strength and high density of the material; in addition, with the improvement of aesthetics, it is required that the zirconia denture has uniform semi-transparency, and the semi-transparency of the zirconia denture has strict requirements. Therefore, it is urgent to develop an equipment and process capable of rapidly sintering zirconia denture to meet the requirements of high strength and high density, and to meet the requirement of semi-transparency. SUMMARY

[0003] A first object of the application is to provide an equipment capable of rapidly sintering zirconia denture to meet the process requirements of rapid heating, uniform heating and rapid cooling in the zirconia sintering process.

[0004] A second object of the application is to provide a zirconia ceramic microwave sintering process meeting the requirements of high strength and high density.

[0005] To achieve the above objects, the technical solutions of the application are as follows:

[0006] A zirconia denture microwave rapid sintering equipment, comprising a sealed furnace shell, a heat preservation structure, a rapid cooling mechanism, a microwave auxiliary heating structure, a microwave generator and an electric control system.

[0007] The sealed furnace shell is a cuboid of non-magnetic metal material, one of the surfaces is a microwave feeding surface, one surface is a furnace door, and the remaining surfaces are non-microwave feeding surfaces, and the microwave feeding surface is provided with a plurality of microwave feeding entrances.

[0008] The heat preservation structure is arranged inside the sealed furnace shell, and a hollow hearth is formed inside the heat preservation structure.

[0009] The rapid cooling mechanism is arranged on the non-microwave feeding surface.

[0010] The microwave auxiliary heating structure is composed of at least three microwave auxiliary heating plates.

[0011] The microwave generator is arranged outside the microwave feeding surface through the microwave feeding entrance.

[0012] As a preferred embodiment of the present application, the rapid cooling mechanism is connected with the furnace through a ceramic tube, which penetrates the heat preservation structure and the non-microwave feeding surface;

[0013] The rapid cooling mechanism is composed of an air outlet pipe, a jet nozzle and a flow guide pipe;

[0014] The air outlet pipe is a circular pipe, and an air inlet is arranged on the side surface of the air outlet pipe;

[0015] The jet nozzle comprises an air inlet pipe and a converging pipe, the air inlet pipe is a short cylindrical pipe, the converging pipe is a tapered pipe, the air inlet pipe and the converging pipe are sealingly connected at the maximum inner diameter thereof, the jet nozzle is sealingly connected with the end surface of the air outlet pipe close to the air inlet, and the converging pipe is located inside the air outlet pipe;

[0016] The flow guide pipe is sealingly connected with the air outlet pipe through the air inlet.

[0017] As a preferred embodiment of the present application, the taper of the converging pipe is 18°-24°, the ratio of the minimum inner diameter d1 of the converging pipe to the maximum inner diameter d2 is 0.4-0.7, and the maximum inner diameter d2 of the converging pipe is the same as the inner diameter d3 of the air inlet pipe;

[0018] The ratio of the inner diameter d4 of the flow guide pipe to the inner diameter d3 of the air inlet pipe is 0.65-0.75;

[0019] Taking the end surface of the minimum inner diameter of the converging pipe as a reference line, the distance between the radial center line of the flow guide pipe and the reference line is 1 / 2 of the minimum inner diameter d1 of the converging pipe, and the allowable deviation range is ±1 / 8d1;

[0020] The length of the air outlet pipe is greater than the length of the converging pipe, and the excess value is not less than 4 times the inner diameter of the air outlet pipe.

[0021] As a preferred embodiment of the present application, the end surface of the air inlet pipe is connected with a variable frequency high pressure fan;

[0022] The end surface of the flow guide pipe is provided with a connecting flange, and the rapid cooling mechanism is mechanically connected with the non-microwave feeding surface through the connecting flange.

[0023] As a preferred embodiment of the present application, the microwave auxiliary heating plate is arranged on the inner wall of the heat preservation structure and does not face the microwave feeding surface directly, and forms a stable frame structure;

[0024] As a preferred embodiment of the present application, the material of the microwave auxiliary heating plate is a high-temperature-resistant strong dielectric loss material;

[0025] The ratio of the microwave load H0 of the microwave auxiliary heating plate to the microwave load H1 of the heated denture material is 0.8-1.2.

[0026] The microwave load H0 is the product of the microwave dielectric loss constant and the mass of the microwave auxiliary hot plate; the microwave load H1 is the product of the microwave dielectric loss constant and the mass of the heated denture material at 300-350 DEG C.

[0027] As a preferred embodiment of the application, the electric control system is connected with the microwave generator and the variable frequency high pressure fan.

[0028] The electric control system is further provided with a temperature sensor.

[0029] A microwave rapid sintering process for zirconia dentures, characterized in that it comprises the following steps:

[0030] S1, preheating: heating the denture from room temperature to 310-360 DEG C by microwave heating, with a heating rate of 5-15 DEG C / min;

[0031] S2, heating stage A: heating the denture from 310-360 DEG C to 900-950 DEG C, with a heating rate of 10-40 DEG C / min;

[0032] S3, holding stage A: holding at 900-950 DEG C for 10-30 min;

[0033] S4, heating stage B: heating the denture from 900-950 DEG C to 1450-1580 DEG C, with a heating rate of 5-25 DEG C / min;

[0034] S5, holding stage B: holding at 1450-1580 DEG C for 10-120 min;

[0035] S6, rapid cooling A: rapidly cooling the denture from 1450-1580 DEG C to 1300-1340 DEG C, with a cooling rate of 25-150 DEG C / min;

[0036] S7, holding stage C: holding at 1300-1340 DEG C for 10-30 min;

[0037] S8, cooling: cooling the denture to 200 DEG C at a cooling rate of 15-40 DEG C / min.

[0038] Compared with the prior art, the application has the following beneficial effects:

[0039] The technical scheme of the present application combines the advantages of microwave heating, such as rapid heating and synchronous heating, and on the basis of conventional microwave sintering equipment, a microwave auxiliary heating structure and a rapid cooling mechanism are added; the microwave auxiliary heating structure ensures that the zirconia ceramic material can be rapidly heated at a low temperature (below 300 DEG C), and further increases the uniformity of heating, greatly improving the heating efficiency; the rapid cooling mechanism can rapidly cool and the cooling rate can be controlled. BRIEF DESCRIPTION OF DRAWINGS

[0040] The present application will be further described in detail below in combination with the drawings and specific implementation methods.

[0041] Figure 1 is a structural schematic diagram of the present application;

[0042] Figure 2 is a structural schematic diagram of the present application Figure 1 in A-A direction;

[0043] Figure 3 is a structural schematic diagram of the present application Figure 2 in B-B direction;

[0044] Figure 4 is a structural schematic diagram of the rapid cooling mechanism of the present application Figure 1 ;

[0045] Figure 5 is a structural schematic diagram of the present application Figure 4 in C-C direction. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application, that is, the described examples are only a part of the examples of the present application, but not all the examples. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0048] The specific implementation of the present application will be described below in combination with Figures 1-5 ;

[0049] Example 1:

[0050] The application relates to a zirconia denture microwave rapid sintering device, which comprises a sealed furnace shell 11, a heat preservation structure 12, a rapid cooling mechanism 13, a microwave auxiliary heating structure 14, a microwave generator 15 and an electric control system.

[0051] The sealed furnace shell 11 is a cuboid made of non-magnetic metal material, one surface of which is a microwave feeding surface, one surface is a furnace door, and the remaining surfaces are non-microwave feeding surfaces; the microwave feeding surface is provided with a plurality of microwave feeding entrances.

[0052] The heat preservation structure 12 is arranged in the sealed furnace shell 11, and a hollow furnace chamber is formed in the heat preservation structure 12.

[0053] The rapid cooling mechanism 13 is arranged on the non-microwave feeding surface.

[0054] The microwave auxiliary heating structure 14 is composed of at least three microwave auxiliary heating plates.

[0055] The microwave generator 15 is arranged outside the microwave feeding surface through the microwave feeding entrances.

[0056] The microwave sintering device needs to seal the microwave in a sealed furnace shell 11, and the furnace shell is made of non-magnetic metal material to prevent ferromagnetic materials from absorbing microwaves and heating in the microwave field, thereby avoiding adverse consequences; the microwave generator 15 is fixed on a microwave feeding surface, which facilitates the reasonable design of the microwave auxiliary heating structure 14; and the rapid cooling mechanism 13 can facilitate the adjustment of the cooling speed of the zirconia denture.

[0057] The zirconia denture has very low microwave absorption capacity below 300 DEG C, and the direct microwave heating has very slow heating speed; the microwave auxiliary heating plates absorb microwaves to generate heat, and the heat is transmitted to the denture, so that the denture material can be rapidly heated; the microwave absorption capacity of the zirconia denture increases with the increase of temperature, and the inflection point of the microwave absorption capacity appears at 300 DEG C, so that the zirconia denture can strongly absorb microwaves above 300 DEG C to realize synchronous heating. In the process of microwave heating, the energy source required by the heated object is provided by the microwave absorption of the heated object, and the heat preservation structure 12 does not absorb microwaves; the temperature of the heated object is higher than that of the inner wall of the heat preservation structure 12, so that a temperature cold spot is generated between the heated object and the inner wall of the heat preservation structure 12 in the furnace chamber, thereby causing uneven heating; unless the temperature difference between the inner wall of the heat preservation structure 12 and the heated object is very small during the heating process, which is impossible in the case of rapid heating; the microwave auxiliary heating plates are arranged on the inner wall of the heat preservation structure 12, the microwave auxiliary heating plates and the heated object absorb microwaves synchronously, and the temperature difference between them is very small, so that the heating uniformity is further improved.

[0058] Beneficially, the rapid cooling mechanism 13 is composed of a metal air outlet pipe 19, a jet nozzle 20 and a guide pipe 21; the rapid cooling mechanism 13 is connected with the furnace through a ceramic pipe 16, which penetrates the heat preservation structure 12 and the non-microwave feeding surface; the air outlet pipe 19 is a circular pipe, and the side of the air outlet pipe 19 is provided with an air inlet; the jet nozzle 20 includes an air inlet pipe and a contraction pipe, the air inlet pipe is shaped as a short cylindrical pipe, the contraction pipe is shaped as a tapered pipe, the air inlet pipe and the contraction pipe are welded between the largest inner diameters thereof, the jet nozzle 20 is welded with the end surface of the air outlet pipe 19 close to the air inlet, and the contraction pipe is located inside the air outlet pipe 19; the guide pipe 21 is welded with the air outlet pipe 19 perpendicularly through the air inlet.

[0059] Beneficially, the taper of the contraction pipe is 22.29°; the minimum inner diameter d1 of the contraction pipe is 16 mm, the inner diameter d3 of the air inlet pipe is 30 mm, and the inner diameter d4 of the guide pipe 21 is 21 mm; the distance between the radial center line of the guide pipe 21 and the end surface of the minimum inner diameter of the contraction pipe is 8 mm; the length of the air outlet pipe 19 is 325 mm.

[0060] Beneficially, the end surface of the air inlet pipe is connected with a variable frequency high pressure fan 22; the end surface of the guide pipe 21 is provided with a connecting flange 23, and the rapid cooling mechanism 13 is mechanically connected with the non-microwave feeding surface through the connecting flange 23.

[0061] When the high speed air flow generated by the variable frequency high pressure fan 22 passes through the contraction pipe from the air inlet pipe, the air flow becomes thin and the gas flow speed is accelerated, and a vacuum area is formed at the rear side of the outlet of the contraction pipe; the guide pipe 21 and the air outlet pipe 19 are welded and sealed, the contraction pipe is arranged in the air outlet pipe 19, and the air inlet is arranged in the vacuum area; the high temperature ceramic pipe is inserted into the guide pipe 21 and communicates with the furnace, and the high temperature gas (greater than 1300℃) in the furnace is directly sucked into the air outlet pipe 19 through the guide pipe 21 and mixed with the high speed air flow. Through such design, the high temperature gas in the furnace is extracted to achieve the effect of rapid cooling, and the high temperature gas is mixed with a large amount of cold air, so that the gas temperature is rapidly reduced, and damage to the equipment caused by overflow of high temperature gas is avoided.

[0062] The taper of the contraction pipe is 18-24°, the ratio of the minimum inner diameter d1 of the contraction pipe to the maximum inner diameter d2 is 0.4-0.7, the ratio of the inner diameter d4 of the drainage pipe 21 to the inner diameter d3 of the air inlet pipe is 0.65-0.75, and the distance between the radial center line of the drainage pipe 21 and the minimum inner diameter end face of the contraction pipe is 1 / 2 of the minimum inner diameter d1 of the contraction pipe, with an allowable deviation range of ±1 / 8d1; these designs are to ensure that the pressure loss of high-speed gas passing through the contraction pipe is minimum, the formed vacuum area is larger, the vacuum pressure is higher, and the drainage pipe 21 is as close as possible to the center position of the vacuum area to achieve the best air extraction effect. The frequency of the variable frequency high-pressure fan 22 can be adjusted according to the need to adjust the air extraction amount, so as to control the cooling speed.

[0063] The length of the air outlet pipe 19 is greater than the length of the contraction pipe, and the exceeding value is not less than 4 times the inner diameter of the air outlet pipe 19, so as to ensure that the high-temperature gas and the high-speed air flow are fully mixed.

[0064] Beneficially, the microwave auxiliary heating plate is arranged on the inner wall of the heat preservation structure 12 and does not face the microwave feeding surface, and forms a stable frame structure, and the material of the microwave auxiliary heating plate is silicon nitride; the ratio of the microwave load H0 of the silicon nitride plate to the microwave load H1 of the heated false tooth material is 1.0; the microwave load H0 is the product of the microwave dielectric loss constant and the mass of the silicon nitride plate; the microwave load H1 is the product of the microwave dielectric loss constant and the mass of the heated false tooth material at 330°C. The electric control system is in control connection with the microwave generator 15 and the variable frequency high-pressure fan 22; the electric control system is further provided with a temperature sensor.

[0065] The microwave auxiliary heating plate does not face the microwave feeding surface and forms a stable frame structure, so as to facilitate the false tooth to enter and exit the kiln; through the electric control system and the temperature sensor, the microwave power and the air extraction amount can be flexibly adjusted according to the process needs.

[0066] Silicon nitride is a strong wave-absorbing material with good thermal vibration ability, high temperature resistance and high strength, and has no pollution to the false tooth at high temperature, so it is an excellent microwave auxiliary heating material. By regulating the microwave load ratio of the microwave auxiliary heating material and the heated false tooth, the false tooth can be heated by heat conduction at a low temperature stage, and the microwave load of the two is equivalent during rapid heating above the temperature inflection point, so that synchronous heating and minimum temperature difference are realized, and the temperature uniformity is improved.

[0067] A microwave rapid sintering process for a zirconia false tooth includes the following steps:

[0068] S1, preheating: heating the false tooth from room temperature to 360°C by microwave heating, and the heating speed is 15°C / min;

[0069] S2, temperature rising stage A: the denture is heated from 360℃ to 950℃ at a speed of 40℃ / min;

[0070] S3, temperature holding stage A: holding at 950℃ for 30min;

[0071] S4, temperature rising stage B: the denture is heated from 950℃ to 1580℃ at a speed of 25℃ / min;

[0072] S5, temperature holding stage B: holding at 1580℃ for 120min;

[0073] S6, rapid cooling stage A: the denture is rapidly cooled from 1580℃ to 1340℃ at a speed of 150℃ / min;

[0074] S7, temperature holding stage C: holding at 1340℃ for 30min;

[0075] S8, cooling: the denture is cooled to 200℃ at a speed of 40℃ / min.

[0076] Example two:

[0077] The sintered sample is a full crown 3 unit below bridge of the brand of Edison porcelain, and the above microwave sintering,

[0078] Wherein the parameters of the rapid cooling mechanism: the taper of the contraction pipe is 18°, d1:d2=0.4, d4:d3=0.65, the distance between the radial center line of the drainage pipe and the reference line is 3 / 8d1; the length of the air outlet pipe is greater than the length of the contraction pipe, and the exceeding value is equal to 4 times the inner diameter of the air outlet pipe;

[0079] The parameters of the microwave auxiliary heating structure: H0:H1=0.8, H1 is the product of the microwave dielectric loss constant and the mass of the heated denture material at 300℃.

[0080] The sintering process includes the following steps:

[0081] S1, preheating: the denture is heated from room temperature to 310℃ by microwave heating at a speed of 10℃ / min;

[0082] S2, temperature rising stage A: the denture is heated from 310℃ to 900℃ at a speed of 30℃ / min;

[0083] S3, temperature holding stage A: holding at 900℃ for 20min;

[0084] S4, temperature rising stage B: the denture is heated from 900℃ to 1530℃ at a speed of 15℃ / min;

[0085] S5, temperature holding stage B: holding at 1530℃ for 10min;

[0086] S6, rapid cooling A: the denture is rapidly cooled from 1530℃ to 1310℃, the cooling rate is 80℃ / min;

[0087] S7, holding stage C: holding at 1310℃ for 10min;

[0088] S8, cooling: the denture is cooled to 200℃ at a cooling rate of 30℃ / min.

[0089] The zirconia denture has poor wave absorption performance from room temperature to 310℃, mainly relying on the heat conduction of the microwave auxiliary heating plate, so the denture cannot be heated synchronously, and therefore the heating rate needs to be slow.

[0090] 900℃ holding for 10min is because the denture has a dyeing agent, which needs to be fully reacted and colored at this temperature.

[0091] Holding at 1530℃ for 10min is to make the grain growth sufficient and more uniform.

[0092] Rapid cooling from 1530℃ to 1310℃ at a rate of 80℃ / min is to rapidly cool the denture under the condition of ensuring that the denture does not deform by stress, and not to let the grain grow.

[0093] Holding at 1310℃ for 10min is to eliminate the stress generated in the rapid cooling process.

[0094] Example Three:

[0095] The sintered sample is a half mouth full tooth of the brand of Edeet, and the above microwave sintering,

[0096] The rapid cooling mechanism parameters are: the taper of the contraction pipe is 24°, d1:d2=0.7, d4:d3=0.75, the distance between the radial center line of the drainage pipe and the reference line is 5 / 8d1; the length of the air outlet pipe is greater than the length of the contraction pipe, and the exceeding value is greater than 4 times the inner diameter of the air outlet pipe.

[0097] The microwave auxiliary heating structure parameters are: H0:H1=1.2, H1 is the product of the microwave dielectric loss constant and the mass of the heated denture material at 350℃.

[0098] The sintering process includes the following steps:

[0099] S1, preheating: the denture is heated from room temperature to 320℃ by microwave heating, the heating rate is 5℃ / min;

[0100] S2, heating stage A: the denture is heated from 320℃ to 900℃ at a rate of 10℃ / min;

[0101] S3, holding stage A: holding at 900℃ for 20min;

[0102] S4, temperature rising stage B: the denture is heated from 900℃ to 1450℃ at a speed of 5℃ / min;

[0103] S5, holding stage B: holding at 1450℃ for 60min;

[0104] S6, rapid cooling stage A: the denture is rapidly cooled from 1450℃ to 1340℃ at a speed of 25℃ / min;

[0105] S7, holding stage C: holding at 1340℃ for 30min;

[0106] S8, cooling: the denture is cooled to 200℃ at a speed of 15℃ / min.

[0107] Comparative Example 1:

[0108] The sintered sample is Edison brand porcelain full crown 3 units below the bridge, and the conventional electric furnace is heated:

[0109] S1, the denture is heated from 20℃ to 900℃ at a speed of 10℃ / min;

[0110] S2, holding at 900℃ for 20min;

[0111] S3, heating from 900℃ to 1530℃ at a speed of 5℃ / min;

[0112] S4, holding at 1530℃ for 120min;

[0113] S5, cooling to 300℃ at a speed of 10℃ / min.

[0114] Comparative Example 2:

[0115] The sintered sample is Edison brand Rengcai 3D half mouth full tooth, and the conventional electric furnace is heated:

[0116] S1, the denture is heated from 20℃ to 900℃ at a speed of 5℃ / min;

[0117] S2, holding at 900℃ for 20min;

[0118] S3, heating from 900℃ to 1450℃ at a speed of 2℃ / min;

[0119] S4, holding at 1450℃ for 120min;

[0120] S5, cooling from 1450℃ to 900℃ at a speed of 3℃ / min;

[0121] S6, cooling from 900℃ to 300℃ at a rate of 7℃ / min.

[0122] From the experimental data of Example 1 and Example 2, and compared with Comparative Example 1 and Comparative Example 2, it can be concluded that the sintering equipment of the application can control the rapid heating and rapid cooling of the zirconia denture, and the rapid cooling in the temperature range from the sintering temperature to the phase transition temperature allows the grains to not grow too large before dropping below the phase transition temperature, thereby making the semi-transparency meet the requirements.

[0123] The technical process principle of the application is as follows:

[0124] In addition to the high requirement on the strength, the zirconia denture also has strict requirements on the semi-transparency. Research shows that light scattering is the main factor affecting the semi-transparency of zirconia, and the pore and grain size have the greatest influence on the scattering; the pore is one of the largest scattering centers of the zirconia denture, and when the pore size is greater than 200-400nm, it can significantly cause light scattering and reduce the semi-transparency, especially when the pore size is close to the incident light wavelength; when the grain size of the denture is close to the wavelength of visible light, the scattering of the grain to light is the most obvious, and the semi-transparency is the lowest.

[0125] Therefore, the finer the grain, the higher the density, the smaller the porosity, the smaller the light scattering, and the better the semi-transparency. The grain diameter should be controlled to be out of the range of the wavelength of visible light (0.38-0.70μm), and the conventional sintering is to ensure the semi-transparency by increasing the sintering temperature, prolonging the holding time, and increasing the grain diameter to more than 0.70μm.

[0126] Compared with the conventional sintering, the microwave sintering increases the heating speed, reduces the sintering temperature, and significantly reduces the sintering time, and the obtained zirconia grain is finer and the microstructure is more uniform. However, in the process of reducing the temperature from the sintering temperature (1450℃-1580℃) to the phase transition temperature (1330℃-1350℃) after the sintering is completed, the grain will grow, and if the cooling time is too long, the grain size may grow to the range of the wavelength of visible light (0.38-0.70μm), and the semi-transparency is reduced.

[0127] One of the solutions is to rapidly cool in the temperature range from the sintering temperature to the phase transition temperature, so that the grain does not grow too large before dropping below the phase transition temperature.

[0128] In the description of the application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0129] The above merely illustrates and explains the structure of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or replace them with similar ways, as long as they do not deviate from the structure of the present application or exceed the scope defined by the present claims.

Claims

1. A zirconia denture microwave rapid sintering device, characterized by: The equipment comprises a sealed furnace shell, a heat preservation structure, a rapid cooling mechanism, a microwave auxiliary heating structure, a microwave generator and an electric control system. The sealed furnace shell is a cuboid made of non-magnetic metal material, one of the surfaces of which is a microwave feeding surface, one surface is a furnace door, and the remaining surfaces are non-microwave feeding surfaces, and the microwave feeding surface is provided with a plurality of microwave feeding inlets. The heat preservation structure is arranged inside the sealed furnace shell, and a hollow hearth is formed inside the heat preservation structure. The rapid cooling mechanism is arranged on the non-microwave feeding surface. The microwave auxiliary heating structure is composed of at least three microwave auxiliary heating plates. The microwave generator is arranged outside the microwave feeding surface through the microwave feeding inlets. The rapid cooling mechanism and the hearth are connected through a ceramic pipe, and the ceramic pipe penetrates through the heat preservation structure and the non-microwave feeding surface. The rapid cooling mechanism is composed of a metal air outlet pipe, a jet nozzle and a flow guide pipe. The air outlet pipe is a circular pipe, and the side surface of the air outlet pipe is provided with an air inlet. The jet nozzle comprises an air inlet pipe and a contraction pipe, the air inlet pipe is a short cylindrical pipe, the contraction pipe is a tapered pipe, the air inlet pipe and the contraction pipe are sealingly connected at the maximum inner diameter position, the jet nozzle is sealingly connected with the end surface of the air outlet pipe close to the air inlet, and the contraction pipe is located inside the air outlet pipe. The flow guide pipe is sealingly connected with the air outlet pipe through the air inlet. The taper of the contraction pipe is 18°-24°, the ratio of the minimum inner diameter d1 of the contraction pipe to the maximum inner diameter d2 of the contraction pipe is 0.4-0.7, and the maximum inner diameter d2 of the contraction pipe is the same as the inner diameter d3 of the air inlet pipe. The ratio of the inner diameter d4 of the flow guide pipe to the inner diameter d3 of the air inlet pipe is 0.65-0.

75. Taking the minimum inner diameter end surface of the contraction pipe as a reference line, the distance between the radial center line of the flow guide pipe and the reference line is 1 / 2 of the minimum inner diameter d1 of the contraction pipe, and the allowable deviation range is ±1 / 8 d1. The length of the air outlet pipe is greater than the length of the contraction pipe, and the excess value is not less than 4 times the inner diameter of the air outlet pipe.

2. The zirconia denture microwave rapid sintering equipment according to claim 1, wherein: the end surface of the air inlet pipe is connected with a variable frequency high pressure fan; and the end surface of the flow guide pipe is provided with a connecting flange, and the rapid cooling mechanism is mechanically connected with the non-microwave feeding surface through the connecting flange.

3. The zirconia denture microwave rapid sintering equipment according to claim 1, wherein: the microwave auxiliary heating plates are arranged on the inner wall of the heat preservation structure and do not face the microwave feeding surface directly, and form a stable frame structure.

4. The zirconia denture microwave rapid sintering equipment according to claim 3, wherein: the microwave auxiliary heating plates are made of high-temperature-resistant strong dielectric loss material; and the ratio of the microwave load H0 of the microwave auxiliary heating plates to the microwave load H1 of the heated denture material is 0.8-1.

2. ​ ​ ​ ​ ​ The microwave load H0 is the product of the microwave dielectric loss constant and the mass of the microwave auxiliary hot plate; the microwave load H1 is the product of the microwave dielectric loss constant and the mass of the heated denture material at 300-350 DEG C.

5. The zirconium oxide denture microwave rapid sintering equipment according to claim 2 is characterized in that: The electric control system is connected with the microwave generator and the variable frequency high pressure fan; The electric control system is also provided with a temperature sensor.

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