Vacuum furnace

Abstract

The embodiment of the invention discloses a vacuum furnace, relates to the technical field of injection molding equipment, and solves the problems of long preparation process flow, high energy consumption and relatively high cost of an existing MIM (Metal Injection Molding) piece. The vacuum furnace comprises a furnace body, a plurality of partition doors and a vacuumizing device. A furnace chamber is formed in the furnace body. At least three heating and heat preservation bins distributed in the axial direction are arranged in the furnace cavity, and the at least three heating and heat preservation bins comprise a degreasing bin, a sintering bin and a heat treatment bin which are sequentially distributed. And the degreasing bin, the sintering bin and the heat treatment bin are independently heated. And the degreasing bin is used for thermally degreasing the workpieces. And one of the partition doors separates the degreasing bin from the sintering bin, and the other partition door separates the sintering bin from the heat treatment bin. The vacuumizing device communicates with the degreasing bin, the sintering bin and the heat treatment bin. According to the vacuum furnace, the degreasing bin, the sintering bin and the heat treatment bin are integrated in the same furnace body, required process equipment is reduced, the cost is reduced, the energy consumption is low, and the time required by the process flow is shortened.

Description

Technical Field

[0001] This application relates to the technical field of injection molding equipment, and particularly to a vacuum furnace. Background Art

[0002] Metal injection molding (MIM) is a preparation method in which a plasticized mixture of metal powder and its binder is injected into a mold to form a green part, and the required shaped part is obtained through debinding and sintering densification. The manufacturing process of MIM parts includes heat treatment processes such as mixing, injection molding, acid debinding, thermal debinding, sintering, and heat treatment (such as solution aging, carburizing, nitriding, etc.). The preparation process flow is long, the energy consumption is high, and the cost is relatively high. Summary of the Invention

[0003] An embodiment of this application provides a vacuum furnace, which solves the problems of long preparation process flow, high energy consumption, and high cost of existing MIM parts.

[0004] To achieve the above object, this application adopts the following technical solutions:

[0005] An embodiment of this application provides a vacuum furnace, which includes a furnace body, at least two partition doors, and a vacuum pumping device. Among them, a furnace cavity is formed inside the furnace body. The furnace cavity includes at least three heating and heat preservation chambers distributed along the axial direction, which are hereinafter referred to as "multiple heating and heat preservation chambers" for the convenience of description. The multiple heating and heat preservation chambers include a debinding chamber, a sintering chamber, and a heat treatment chamber distributed in sequence. That is, the sintering chamber is located between the debinding chamber and the heat treatment chamber. The debinding chamber is mainly used for thermal debinding of the workpiece to be processed. For the convenience of description, hereinafter, "at least two partition doors" are referred to as "multiple partition doors". One of the multiple partition doors separates the debinding chamber from the sintering chamber, and the other of the multiple partition doors separates the sintering chamber from the heat treatment chamber. Therefore, the debinding chamber, the sintering chamber, and the heat treatment chamber can be heated separately. The vacuum pumping device is respectively connected to the debinding chamber, the sintering chamber, and the heat treatment chamber.

[0006] Compared with the prior art, the vacuum furnace of the embodiment of this application integrates the debinding chamber, the sintering chamber, and the heat treatment chamber in the same furnace body, reduces the number of devices required for MIM part preparation, reduces the cost, shortens the time required for the process flow, and reduces the energy consumption. Moreover, the two partition doors separate the debinding chamber from the sintering chamber and the sintering chamber from the heat treatment chamber respectively, so that the thermal debinding process, the sintering process, and the heat treatment process are completed in different chamber rooms respectively. Even if the degreasing volatiles of the workpiece are not completely removed during the thermal debinding process, it will not affect the subsequent sintering process of the workpiece. And, the vacuum pumping device can pump the debinding chamber, the sintering chamber, and the heat treatment chamber into a vacuum. Thus, vacuum debinding, vacuum sintering, and vacuum heat treatment can be realized. Sintering the workpiece in a vacuum can make the formed workpiece have low density and high oxygen content.

[0007] Based on the above structure, any one of the above heating and heat preservation bins includes a heat preservation cylinder and a heating device. The heat preservation cylinder is sleeved inside the furnace body, and a furnace installation cavity is formed inside the heat preservation cylinder. The furnace installation cavity is used to place the furnace loaded with workpieces to be processed. The heating device is arranged inside the furnace installation cavity. The heating device can heat the workpieces to be processed inside the furnace. And, since the time required for the sintering process is longer than the time required for the debinding process and the heat treatment process, in some embodiments of the present application, the length of the furnace installation cavity in the above sintering bin can be more than twice the length of the furnace installation cavity in the debinding bin, or can also be more than twice the length of the furnace installation cavity in the heat treatment bin.

[0008] For example, the length of the furnace installation cavity of the heat preservation cylinder in the debinding bin and the length of the furnace installation cavity of the heat preservation cylinder in the heat treatment are both more than one times the length of the furnace required for accommodating. And the length of the furnace installation cavity of the heat preservation cylinder in the above sintering bin is more than twice the length of the furnace required for accommodating. Thus, the workpieces to be processed in two or more furnaces can be sintered simultaneously, improving the sintering efficiency and reducing the process flow time.

[0009] In addition, in order to realize the transfer of the furnace loaded with workpieces to be processed from the debinding bin to the sintering bin, or from the sintering bin to the heat treatment bin, in some embodiments of the present application, the vacuum furnace further includes a plurality of driving support columns and a first driving device. The first ends of the plurality of driving support columns are respectively arranged inside the heat preservation cylinders of the plurality of heating and heat preservation bins. And at least one driving support column is arranged inside any one of the heating and heat preservation bins. The first end of the driving support column can support the furnace loaded with workpieces to be processed inside the heat preservation cylinder. The first driving device is in transmission connection with the above plurality of driving support columns. The first driving device is used to drive the driving support column inside any one of the heat preservation cylinders to move the furnace loaded with workpieces to be processed into the heat preservation cylinder of another adjacent heating and heat preservation bin.

[0010] And, the above driving support column cannot affect the heat preservation performance of the heat preservation cylinder. So, in some embodiments of the present application, the heat preservation cylinder of the above heating and heat preservation bin includes a heat preservation cylinder body and a heat preservation baffle. The cylindrical wall of the heat preservation cylinder body extending along the circumferential direction of the furnace body is provided with a notch, and the heat preservation baffle is matched with the notch. The driving support column is hermetically connected to the heat preservation baffle. The driving support column can drive the heat preservation baffle to move, so that the heat preservation baffle can move to close the notch of the heat preservation cylinder body, or move into the heat preservation cylinder body. Thus, both the heat preservation performance of the heat preservation cylinder is realized, and at the same time, the function of the driving support column for transferring the furnace can also be realized.

[0011] Moreover, the above heating device cannot affect the transmission operation of the transmission support column and the movement of the furnace chamber. Therefore, in some embodiments of the present application, the heating device is provided with an avoidance opening for avoiding the transmission support column, so that the heating device does not affect the movement of the support column. And the above heating device can be distributed in a circumferential direction within the heat preservation cylinder. The heating device can heat the workpiece in the furnace chamber from all directions in the circumferential direction. During the processes of vacuum degreasing, vacuum sintering, and vacuum heat treatment, the temperature uniformity of the workpiece is better. The heating device can specifically be a heating plate.

[0012] Considering that the notch of the heat preservation cylinder body will be opened during the process of transporting the furnace chamber loaded with the workpiece to be processed, the high temperature in the heating and heat preservation chamber will radiate towards the furnace body, resulting in the softening of the furnace body. Therefore, in some embodiments of the present application, the above vacuum cylinder further includes a heat insulation device located outside the heat preservation cylinder and disposed opposite to the heat preservation baffle. The outer circumference of the projection of the heat insulation device on the heat preservation cylinder is located outside the notch of the heat preservation cylinder body. Therefore, the heat insulation device can block the exposed notch of the heat preservation cylinder body after the heat preservation baffle is removed, avoiding the problem that the high temperature in the heating and heat preservation chamber radiates towards the furnace body from this location and causing the softening of the furnace body.

[0013] And, in order to cooperate with the transmission of the furnace chamber loaded with the workpiece to be processed, the above partition door needs to close or open the heating and heat preservation chamber according to the transmission requirements. In some embodiments of the present application, the above partition door includes an annular fixed door body, an opening mechanism, and a second driving device. Among them, the annular fixed door body is fixed in the furnace chamber and is arranged along the radial direction of the furnace chamber. The opening mechanism includes a circular closing door and one or more annular movable doors, both of which are arranged along the radial direction of the furnace chamber. One or more annular movable doors continuously block a part of the inner cavity of the annular fixed door body from the outside to the inside in a direction away from the annular fixed door body, and the circular closing door blocks the remaining part of the inner cavity of the annular fixed door body. Any one of the annular movable doors includes two semi-circular arc-shaped movable door bodies, and the two movable door bodies can be spliced into a circular door body or separated from each other. The circular closing door includes two semi-circular closing door panels, and the two closing door panels can be spliced into a circular door or separated from each other. The second driving device is in transmission connection with the above opening mechanism. The second driving device can drive the two movable door bodies of any one of the annular movable doors and the two closing door panels of the circular closing door to move away from each other to open the annular fixed door body; or drive the two movable door bodies of any one of the annular movable doors and the two closing door panels of the circular closing door to move closer to each other to close the annular fixed door body. This partition door can close the annular fixed door body through one or more annular movable doors and the circular closing door, and the multi-layer door body closing structure ensures the closing reliability of the partition door. And when this partition door switches between opening and closing, the space it occupies in the furnace cavity is also small, and the structure of the vacuum furnace is compact and the volume is small.

[0014] In addition, the annular fixed door body may be provided with a set of the above-mentioned door opening mechanisms on only one axial side, or may be provided with a set of the above-mentioned door opening mechanisms on both axial sides respectively, and the latter is applicable to application scenarios with high sealing requirements.

[0015] Based on the above-mentioned partition door structure, in some embodiments of the present application, the above-mentioned partition door further includes multiple sets of guiding structures, which are respectively arranged between adjacent annular movable doors and the annular fixed door body, and between adjacent annular movable doors and the circular closed door. For the door opening mechanism including two or more annular movable doors, the above-mentioned guiding structures are also arranged between two adjacent annular movable doors. The guiding structures can guide the opening and closing processes of the annular movable doors and the circular closed door, making the movement processes of the annular movable doors and the circular closed door smoother.

[0016] Taking the guiding structure between an adjacent annular movable door and the annular fixed door body as an example, in some embodiments, the above-mentioned guiding structure may include four guide rails and four guide posts. The four guide rails are arranged at intervals on the annular fixed door body and are respectively opposite to two of the movable door bodies in the annular movable door. That is, each movable door body is opposite to two guide rails. The four guide rails all extend along the radial direction of the annular fixed door body. And, two guide posts are respectively arranged on one of the movable door bodies in the annular movable door, and the other two guide posts are respectively arranged on the other movable door body in the annular movable door. And, the four guide posts are located on the side surface of the annular movable door close to the annular fixed door body. The four guide posts can be respectively slidably connected to the four guide rails.

[0017] In addition, in some examples of the present application, the above-mentioned furnace body includes a first furnace door, an intermediate furnace body, and a second furnace door, which are connected in sequence. The degreasing chamber, the sintering chamber, and the heat treatment chamber are all located in the intermediate furnace body. The intermediate furnace body has a first opening and a second opening. The first opening is communicated with the degreasing chamber, and the second opening is communicated with the heat treatment chamber. The first furnace door is used to close or open the first opening, and the second furnace door is used to close or open the second opening. Thus, the furnace chamber loaded with the workpieces to be processed is loaded into the degreasing chamber through the first opening by the first furnace door to achieve feeding; the furnace chamber after the heat treatment of the workpieces is taken out from the heat treatment chamber through the second opening by the second furnace door to achieve discharging.

[0018] In the heat treatment process of the workpiece, in addition to heating, cooling is sometimes also required. Therefore, in some embodiments of the present application, the above-mentioned vacuum furnace further includes a first refrigeration device and a second refrigeration device. The first refrigeration device can be arranged on the first furnace door of the furnace body and is used to refrigerate the degreasing chamber. The second refrigeration device can be arranged on the second furnace door of the furnace body and is used to refrigerate the heat treatment chamber. Thus, forced refrigeration of the degreasing chamber and forced refrigeration of the heat treatment chamber are achieved to meet the cooling requirements during the heat treatment process and to meet the requirement of cooling the degreasing chamber before the next workpiece to be processed enters the degreasing chamber when continuously performing the degreasing process on multiple workpieces.

[0019] Among them, in some examples, the above-mentioned first refrigeration device may include a first refrigeration pipeline, a first forced cooling fan and a first heat exchanger. Among them, the first refrigeration pipeline is communicated with the air inlet of the first forced cooling fan. The first refrigeration pipeline can also be communicated with a storage device storing a refrigeration gas (such as a low-temperature inert protective gas). The first forced cooling fan can be installed on the first furnace door of the furnace body, and the air outlet of the first forced cooling fan can be communicated with the degreasing chamber. The first heat exchanger is installed in the area of the furnace cavity communicated with the degreasing chamber. The first forced cooling fan is used to introduce the refrigeration gas in the first refrigeration pipeline into the degreasing chamber, and exchange heat with the gas in the degreasing chamber through the first heat exchanger. The first heat exchanger can increase the heat exchange contact area between the high-temperature gas in the degreasing chamber and the refrigeration gas introduced by the first forced cooling fan.

[0020] The second refrigeration device includes a second refrigeration pipeline, a second forced cooling fan and a second heat exchanger. Among them, the second refrigeration pipeline is communicated with the air inlet of the second forced cooling fan. The second refrigeration pipeline can also be communicated with a storage device storing a refrigeration gas (such as a low-temperature inert protective gas). The second forced cooling fan can be installed on the second furnace door of the furnace body, and the air outlet of the second forced cooling fan can be communicated with the heat treatment chamber. The second heat exchanger is installed in the area of the furnace cavity communicated with the heat treatment chamber. The second forced cooling fan is used to introduce the refrigeration gas in the second refrigeration pipeline into the heat treatment chamber, and exchange heat with the gas in the heat treatment chamber through the second heat exchanger. The second heat exchanger can increase the heat exchange contact area between the high-temperature gas in the heat treatment chamber and the refrigeration gas introduced by the second forced cooling fan.

[0021] Based on this, in some embodiments of the present application, the above-mentioned first furnace door includes a first outer furnace cover and a first inner cover plate. Among them, the first outer furnace cover is movably connected to the first inner cover plate and is connected to the intermediate furnace body. The first inner cover plate can cover or move away from the first opening of the intermediate furnace body to close or open the first opening. A first buffer cavity is formed between the first outer furnace cover and the first inner cover plate. The above-mentioned first refrigeration device is installed on the first outer furnace cover and is communicated with the first buffer cavity. The first heat exchanger is installed in the first buffer cavity. Thus, when the first inner cover plate moves away from the first opening, by turning on the first refrigeration device, the degreasing chamber can be refrigerated. Similarly, the above-mentioned second furnace door includes a second outer furnace cover and a second inner cover plate. Among them, the second outer furnace cover is movably connected to the second inner cover plate and is connected to the intermediate furnace body. The second inner cover plate can cover or move away from the second opening of the intermediate furnace body to close or open the second opening. A second buffer cavity is formed between the second outer furnace cover and the second inner cover plate. The above-mentioned second refrigeration device is installed on the second outer furnace cover and is communicated with the second buffer cavity. The second heat exchanger is installed in the second buffer cavity. Thus, when the second inner cover plate moves away from the second opening, by turning on the second refrigeration device, the heat treatment chamber can be refrigerated.

[0022] The above-mentioned thermal degreasing process, sintering process and heat treatment process need to introduce some inert protective gases to assist. Therefore, in some embodiments of the present application, the above-mentioned vacuum furnace further includes an intake pipeline, and the intake pipeline is respectively communicated with the degreasing chamber, the sintering chamber and the heat treatment chamber. The intake pipeline can introduce the gases required for the process into the degreasing chamber, the sintering chamber and the heat treatment chamber. It can be understood that the above-mentioned vacuum furnace further includes an exhaust pipeline, and the exhaust pipeline can timely discharge the gases in the heating and insulation chamber.

[0023] Moreover, in some embodiments of the present application, the above-mentioned intake pipeline includes a main intake pipe and three or more intake sub-pipes. The vacuum furnace further includes three or more mass flow meters and three or more control valves. Three intake sub-pipes in the intake pipeline can respectively communicate the main intake pipe with the degreasing chamber, the sintering chamber and the heat treatment chamber. Three mass flow meters are respectively arranged on these three intake sub-pipes, and three control valves are respectively arranged on these three intake sub-pipes. At least one mass flow meter and at least one control valve are provided on any one of the intake sub-pipes. Each intake sub-pipe can perform flow detection through a separate mass flow meter and perform flow control through a separate control valve. Thus, the different gas flow requirements of the thermal degreasing process, sintering process and heat treatment process can be met.

[0024] In addition, degreasing volatiles are generated in the above-mentioned thermal degreasing process, and this gas cannot be directly discharged. Therefore, in some embodiments of the present application, the above-mentioned vacuum furnace further includes a wax replenisher, and the wax replenisher is communicated with the degreasing chamber. The wax replenisher can collect the degreasing volatiles in the degreasing chamber to avoid direct discharge and environmental pollution. Brief Description of the Drawings

[0025] To illustrate the technical solutions of the embodiments of the present application, the drawings required for the embodiments of the present application will be described below.

[0026] Figure 1 Schematic cross-sectional view of the vacuum furnace of the embodiment of the present application along the first direction;

[0027] Figure 2 Schematic cross-sectional view of the vacuum furnace of the embodiment of the present application along the second direction;

[0028] Figure 3 Schematic structural view of the first type of partition door in the vacuum furnace of the embodiment of the present application;

[0029] Figure 4 Exploded view of the first type of partition door in the vacuum furnace of the embodiment of the present application;

[0030] Figure 5a Schematic structural view of the splicing of two movable door bodies in the annular movable door of the vacuum furnace of the embodiment of the present application;

[0031] Figure 5b Schematic structural view of the separation of two movable door bodies in the annular movable door of the vacuum furnace of the embodiment of the present application;

[0032] Figure 6a Schematic structural view of the splicing of two closed door panels in the circular closed door of the vacuum furnace of the embodiment of the present application;

[0033] Figure 6b Schematic structural view of the separation of two closed door panels in the annular movable door of the vacuum furnace of the embodiment of the present application;

[0034] Figure 7 Schematic structural view of the second type of partition door in the vacuum furnace of the embodiment of the present application;

[0035] Figure 8 Schematic structural view of the third type of partition door in the vacuum furnace of the embodiment of the present application;

[0036] Figure 9 Exploded view of the fourth type of partition door in the vacuum furnace of the embodiment of the present application.

[0037] Reference Numerals in the Drawings:

[0038] 1000 - Furnace chamber; 100 - Vacuum furnace; 10 - Furnace body; 11 - First furnace door; 111 - First outer furnace cover; 112 - First inner cover plate; 110 - First buffer chamber; 12 - Intermediate furnace body; 121 - First opening; 122 - Second opening; 13 - Second furnace door; 131 - Second outer furnace cover; 132 - Second inner cover plate; 130 - Second buffer chamber; 10S - Furnace cavity; 101S - Heating and insulation bin; 1011 - Degreasing bin; 1012 - Sintering bin; 1013 - Heat treatment bin; 1 - Insulation cylinder; 1S - Furnace chamber installation cavity; 1a - Insulation cylinder body; 10a - Notch; 1b - Insulation baffle; 2 - Heating device; 20a - Avoidance opening; 3 - Temperature detection device; 20 - Partition door; 201 - First partition door; 202 - Second partition door; 21 - Annular fixed door body; 22 - Door opening mechanism; 221 - Circular closing door; 2211 - Closing door plate; 222 - Annular movable door; 2221 - Movable door body; 23 - Second driving device; 231 - Driving motor; 232 - Transmission shaft; 30 - Transmission support column; 301 - First end; 40 - Heat insulation device; 50 - Guide structure; 51 - Guide rail; 52 - Guide post; 60 - First refrigeration device; 61 - First strong cooling fan; 62 - First heat exchanger; 70 - Second refrigeration device; 71 - Second strong cooling fan; 72 - Second heat exchanger; 80 - Intake pipe; 81 - Main intake pipe; 82 - Intake sub - pipe; 801 - Mass flow meter; 90 - Exhaust pipe. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

[0040] Hereinafter, terms such as "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0041] In addition, in the present application, orientation terms such as "upper", "lower", "left", "right", "horizontal" and "vertical" are defined relative to the orientation of the components shown in the drawings. It should be understood that these directional terms are relative concepts, which are used for relative description and clarification, and they may change correspondingly according to the change of the orientation of the components placed in the drawings.

[0042] In this application, unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense. For example, "connection" can refer to the connection of mechanical structures and physical structures. It can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium. It can also be understood that components are physically in contact and electrically conductive, and it can also be understood as a form of connection between different components in a circuit structure through an entity line such as a PCB copper foil or a wire that can transmit electrical signals.

[0043] The manufacturing process of metal injection molding parts includes mixing, injection molding, acid degreasing, thermal degreasing, sintering, and heat treatment processes (such as solution aging, carburizing, nitriding, etc.). Among them, the mixing process is to mix metal powder and binder evenly to obtain a mixture, and the equipment used can be a mixer. The injection molding process is to inject the above mixture in an injection molding machine to obtain a shaped green metal blank. The combination of acid degreasing and thermal degreasing is a two-stage degreasing process, usually acid degreasing first and then thermal degreasing. The acid degreasing process is to treat the above metal blank in nitric acid or oxalic acid vapor, and the equipment used can be a degreasing furnace. The thermal degreasing process is to heat the acid-degreased metal blank at a high temperature (about 600 °C) to remove organic substances. The sintering process is to heat the metal blank after thermal degreasing to a temperature lower than the melting point of its basic components, and then cool it to room temperature by a certain method and speed. The thermal degreasing process and the sintering process can use a degreasing and sintering integrated vacuum sintering furnace, and the treatment time is 22 hours. The heat treatment process includes solution treatment and aging. Solution treatment refers to a heat treatment process in which the workpiece is heated to the high-temperature austenite region and held for insulation, so that the excess phase is fully dissolved into the solid solution and then rapidly cooled to obtain a supersaturated solid solution. Aging refers to holding the workpiece at a higher temperature or room temperature to maintain its shape and size, and the performance of the workpiece changes with time. The equipment used can be a heat treatment furnace. In addition, the heat treatment process can also include heat treatment processes such as carburizing and nitriding.

[0044] According to the above, the above metal injection molding parts need to be prepared by multiple pieces of equipment. Therefore, the process flow is long, the energy consumption is high, the floor area is large, and the operating cost and equipment cost are extremely high. To improve this problem, the embodiments of this application provide a vacuum furnace capable of realizing degreasing, sintering, and heat treatment, which is used for processing workpieces made of metal or ceramic materials.

[0045] Refer to Figure 1, the vacuum furnace 100 includes a furnace body 10, a plurality of partition doors 20, and a vacuum pumping device (not shown in the figure). Among them, the shape of the furnace body 10 is not limited to a cylindrical shape, and can be a regular quadrangular prism, a regular hexagonal prism, etc. A furnace chamber 10S is formed inside the furnace body 10, and the furnace chamber 10S includes three or more heating and heat preservation chambers 101S distributed along the axial direction. For the convenience of description, hereinafter, "at least three heating and heat preservation chambers" will be referred to as "a plurality of heating and heat preservation chambers". The plurality of heating and heat preservation chambers 101S include a degreasing chamber 1011, a sintering chamber 1012, and a heat treatment chamber 1013 that are sequentially distributed. The sintering chamber 1012 is located between the degreasing chamber 1011 and the heat treatment chamber 1013. Therefore, thermal degreasing, sintering, and heat treatment can be carried out sequentially. Moreover, one of the plurality of partition doors 20 separates the degreasing chamber 1011 from the heat treatment chamber 1013, and the other of the plurality of partition doors 20 separates the sintering chamber 1012 from the heat treatment chamber 1013.

[0046] Figure 1 The shown furnace chamber 10S only includes three heating and heat preservation chambers 101S and two partition doors 20. The three heating and heat preservation chambers 101S are respectively a degreasing chamber 1011, a sintering chamber 1012, and a heat treatment chamber 1013 that are sequentially distributed. The two partition doors 20 are respectively a first partition door 201 and a second partition door 202. The first partition door 201 separates the degreasing chamber 1011 from the sintering chamber 1012, and the second partition door 202 separates the sintering chamber 1012 from the heat treatment chamber 1013. The degreasing chamber 1011, the sintering chamber 1012, and the heat treatment chamber 1013 can be heated up independently. When performing the thermal degreasing process, even if the degreasing volatiles of the workpiece are not completely removed, it will not affect the subsequent sintering process of the workpiece.

[0047] The above-mentioned vacuum pumping device can specifically include a mechanical pump and a Roots pump. The vacuum pumping device is respectively communicated with the degreasing chamber 1011, the sintering chamber 1012, and the heat treatment chamber 1013. Thus, vacuum degreasing, vacuum sintering, and vacuum heat treatment can be realized. Moreover, sintering the workpiece under vacuum can make the formed workpiece have a low density and a high oxygen content.

[0048] Therefore, the vacuum furnace 100 of the embodiment of the present application can realize the three process flows of degreasing, sintering, and heat treatment in sequence within the same furnace body, reduce the number of devices required for metal injection molding parts, reduce costs, shorten the time required for the process flow (such as shortening the process treatment time by 10 hours - 15 hours), and reduce energy consumption, floor area, operating costs, and equipment costs.

[0049] The following further describes the structure of the above-mentioned vacuum furnace 100 in detail. Refer to Figure 1 and Figure 2, any of the above heating and heat preservation bins 101S includes a heat preservation cylinder 1 and a heating device 2. Among them, the heat preservation cylinder 1 can be graphite soft felt, graphite hard felt, metal molybdenum heat insulation screen or molybdenum alloy heat insulation screen, etc. The manufacturing material of the heating device 2 can be isostatic graphite, metal molybdenum or tungsten molybdenum alloy, etc. The heat preservation cylinder 1 is sleeved on the furnace body 10. A furnace chamber installation cavity 1S is formed inside the heat preservation cylinder 1. The furnace chamber installation cavity 1S is used to place the furnace chamber 1000 loaded with the workpiece to be processed. Exemplarily, the manufacturing material of the furnace chamber 1000 is specifically isostatic graphite, metal molybdenum or tungsten molybdenum alloy, etc. The heating device 2 is arranged inside the furnace chamber installation cavity 1S. The heating device 2 can heat the furnace chamber 1000 loaded with the workpiece to be processed inside the furnace chamber installation cavity 1S. In some embodiments, the manufacturing material of the above heating device 2 can be the same as that of the furnace chamber 1000, so that during processes such as sintering, the structures of the furnace chamber 1000 and the heating device 2 will not be different at high temperatures, and the furnace chamber 1000 will not generate substances that affect the workpiece. In addition, in order to precisely control the temperature inside the heating and heat preservation bin 101S, the above heating and heat preservation bin 101S further includes, for example, Figure 2 the temperature detection device 3 shown, and the temperature detection device 3 is used to detect the temperature value inside the heat preservation cylinder 1. For example, the temperature detection device 3 is a thermocouple.

[0050] Moreover, since the time required for the sintering process is longer than the time required for the debinding process and the heat treatment process, in some embodiments of the present application, the length of the furnace chamber installation cavity 1S in the above sintering bin 1012 can be more than twice the length of the furnace chamber installation cavity 1S in the debinding bin 1011, and can also be more than twice the length of the furnace chamber installation cavity 1S in the heat treatment bin 1013.

[0051] Exemplarily, the length of the furnace chamber installation cavity 1S of the heat preservation cylinder 1 in the above debinding bin 1011 and the length of the furnace chamber installation cavity 1S of the heat preservation cylinder 1 in the heat treatment are equal to the length of a furnace chamber 1000 loaded with the workpiece to be processed, and the length of the furnace chamber installation cavity 1S of the heat preservation cylinder 1 in the sintering bin 1012 is equal to the length of two furnace chambers 1000 loaded with the workpiece to be processed. Thus, the workpieces to be processed in the two furnace chambers 1000 can be sintered simultaneously, improving the sintering efficiency and reducing the process flow time.

[0052] In addition, according to the distribution manner of the debinding bin 1011, the sintering bin 1012 and the heat treatment bin 1013 in the above furnace body 10, the furnace chamber 1000 loaded with the workpiece to be processed can be sequentially transported to the debinding bin 1011, the sintering bin 1012 and the heat treatment bin 1013 along the axial direction inside the furnace cavity 10S. The distance between two adjacent heating and heat preservation bins 101S is short, shortening the transportation distance and improving the process treatment efficiency. Therefore, in some embodiments of the present application, the above vacuum furnace 100 further includes a transmission structure, and the transmission structure includes a plurality of Figure 2The shown transmission support columns 30 and the first driving device (not shown in the figure), the first ends 301 of the plurality of transmission support columns 30 are respectively disposed in the heat preservation cylinders 1 of the plurality of heat preservation bins 101S. And at least one transmission support column 30 is disposed in any one of the heat preservation bins 101S. The first end 301 of the transmission support column 30 can support the furnace chamber 1000 loaded with the workpiece to be processed in the heat preservation cylinder 1. The above-mentioned first driving device can be in transmission connection with the plurality of transmission support columns 30. The first driving device can drive the transmission support column 30 in any one of the heat preservation cylinders 1 to move, so that the transmission support column 30 can move the above-mentioned furnace chamber 1000 to the furnace chamber installation cavity 1S of another adjacent heat preservation cylinder 1. For example, after the workpiece completes the thermal degreasing process, the transmission support column 30 in the degreasing bin 1011 can move the furnace chamber 1000 loaded with the workpiece in the degreasing bin 1011 to the furnace chamber installation cavity 1S of the sintering bin 1012. The structure of the above-mentioned transmission structure is relatively simple.

[0053] It should be noted that the part of the transmission support column 30 located in the heat preservation cylinder 1 can be made of isostatic graphite material, which is the same as the materials of the heating device 2 and the furnace chamber 1000, to avoid the generation of substances that affect the workpiece in the high-temperature environment. And the part of the transmission support column 30 located outside the heat preservation cylinder 1 can be made of stainless steel, which has high structural strength and good high-temperature resistance.

[0054] And, the above-mentioned transmission structure cannot affect the heat preservation performance during degreasing, sintering or heat treatment. That is, the transmission support column 30 cannot affect the heat preservation effect of the heat preservation cylinder 1. Therefore, in some embodiments of the present application, as Figure 2 shown, the above-mentioned heat preservation cylinder 1 includes a heat preservation cylinder body 1a and a heat preservation baffle 1b. Among them, the heat preservation cylinder body 1a can be matched with the shape of the furnace body 10. Matching means that the shapes of the heat preservation cylinder body 1a and the furnace body 10 are similar or the same. For example, both the heat preservation cylinder body 1a and the furnace body 10 are cylindrical. The barrel wall of the heat preservation cylinder body 1a extending along the axial direction of the furnace body 10 is provided with a notch 10a. The above-mentioned heat preservation baffle 1b is matched with the notch 10a. For example, if the notch 10a is rectangular, the heat preservation baffle 1b is also a rectangle with the same shape and size as the notch 10a. As Figure 2The heat-insulating cylinder body 1a and the heat-insulating baffle 1b shown in the figure are both double-layer structures, with good heat-insulating effect. The area of the notch 10a in the inner layer of the heat-insulating cylinder body 1a is large, while the area in the outer layer of the heat-insulating cylinder body 1a is small. The contact surface between the heat-insulating cylinder body 1a and the heat-insulating baffle 1b is an inclined surface. The above-mentioned transmission support column 30 is hermetically connected to the heat-insulating baffle 1b to ensure the heat-insulating performance at the connection. And, the transmission support column 30 is fixed on the heat-insulating baffle 1b. Therefore, the transmission support column 30 can drive the heat-insulating baffle 1b to move, so that the heat-insulating baffle 1b moves to close the notch 10a of the heat-insulating cylinder body 1a, or moves into the heat-insulating cylinder body 1a. Thus, the structure of the above-mentioned heat-insulating cylinder 1 and the connection method with the transmission support column 30 can not only realize the heat-insulating performance of the heat-insulating cylinder 1, but also realize the function of the transmission support column 30 to transmit the furnace chamber 1000.

[0055] Exemplarily, the transmission support column 30 and the heat-insulating baffle 1b are connected by a snap connection and fixed by a fastener such as a bolt. It can be understood that, similarly, the bolt can be made of isostatic graphite or carbon-carbon composite material.

[0056] In addition to adopting the above structure, in some other embodiments of the present application, the above-mentioned heat-insulating cylinder 1 can also movably connect the above-mentioned heat-insulating baffle 1b to the heat-insulating cylinder body 1a. An avoidance hole for avoiding the transmission support column 30 is arranged at the outer periphery of the heat-insulating baffle 1b. The transmission support column 30 can be hermetically connected to the hole wall of the avoidance hole of the heat-insulating baffle 1b and the wall surface at the notch 10a of the heat-insulating cylinder body 1a. Thus, after the degreasing process or the sintering process is completed and the furnace chamber 1000 needs to be transmitted to the next heating and heat-insulating bin 101S, the heat-insulating baffle 1b can open the notch 10a of the heat-insulating cylinder body 1a. Thus, the entire notch 10a of the heat-insulating cylinder body 1a is exposed, leaving a movement space for the transmission support column 30. When degreasing, sintering or heat treatment is required, the heat-insulating baffle 1b can be covered at the notch 10a of the heat-insulating cylinder body 1a and hermetically connected to the transmission support column 30 and the heat-insulating cylinder body 1a, ensuring good heat-insulating performance of the heat-insulating cylinder 1.

[0057] Based on the structure of the above-mentioned heat-insulating cylinder 1 and the connection method between the heat-insulating cylinder 1 and the transmission support column 30, the movement process of the above-mentioned transmission support column 30 can include moving radially along the heat-insulating cylinder 1 and then moving axially along the heat-insulating cylinder 1. Or, the movement process of the transmission support column 30 can include moving radially along the heat-insulating cylinder 1 and then rotating axially along the heat-insulating cylinder 1. Or, the movement process of the transmission support column 30 can only include rotating axially along the heat-insulating cylinder 1. And, for different movement modes of the transmission support column 30, different first driving devices are required. Exemplarily, the above-mentioned first driving device can include any one or any several of a motor and a cylinder, etc. The number of motors in the first driving device can be one or multiple, and the present application does not limit this. The number of cylinders in the first driving device can be one or multiple, and the present application does not limit this.

[0058] The above heating device 2 also cannot affect the transmission operation of the transmission support column 30 and the movement of the furnace chamber 1000. Therefore, in some embodiments of the present application, as Figure 2 shown, the above heating device 2 can be distributed in a radial circle within the heat preservation cylinder 1 without affecting the movement of the furnace chamber 1000. Moreover, the heating device 2 is provided with an avoidance opening 20a for avoiding the transmission support column 30. Thus, the movement of the transmission support column 30 will not be affected. By way of example, the heating device 2 can specifically be a heating plate.

[0059] In addition, considering the process of transporting the furnace chamber 1000 loaded with workpieces to be processed, when the heat preservation cylinder body 1a is opened, the high temperature in the heat preservation and heating bin 101S will radiate towards the furnace body 10, resulting in softening of the furnace body 10. Therefore, to solve this problem, in some embodiments of the present application, the above vacuum furnace 100 further includes Figure 2 the heat insulation device 40 as shown. The heat insulation device 40 can specifically be a radiation shielding screen. The heat insulation device 40 is located outside the heat preservation cylinder 1 and is disposed opposite to the heat preservation baffle 1b. The outer circumference of the projection of the heat insulation device 40 on the heat preservation cylinder 1 is located outside the notch 10a of the heat preservation cylinder body 1a. Therefore, the heat insulation device 40 can block the notch 10a of the heat preservation cylinder body 1a exposed after the heat preservation baffle 1b is removed, avoiding the problem that the high temperature in the heat preservation and heating bin 101S radiates towards the furnace body 10 and causes softening of the furnace body 10.

[0060] Moreover, in order to cooperate with the transmission of the furnace chamber 1000 loaded with workpieces to be processed, the above partition door 20 needs to seal or open the heat preservation and heating bin 101S according to the transmission requirements. In some embodiments of the present application, referring to Figure 1 and Figure 3 , the above partition door 20 includes an annular fixed door body 21, a door opening mechanism 22 and a second driving device 23. Among them, the annular fixed door body 21 is fixed in the furnace cavity 10S and is arranged along the radial direction of the furnace cavity 10S. The door opening mechanism 22 includes a circular closing door 221 and one or more annular movable doors 222. The circular closing door 221 and one or more annular movable doors 222 are both arranged along the radial direction of the furnace cavity 10S. As Figure 4 shown, any one of the annular movable doors 222 includes two semi-circular arc-shaped movable door bodies 2221. The two movable door bodies 2221 can be spliced into a circular ring-shaped door body as Figure 5a shown, or separated from each other as Figure 5b shown. As Figure 4 shown, any one of the circular closing doors 221 includes two semi-circular closing door panels 2211. The two closing door panels 2211 can be spliced into a circular door as Figure 6a shown, or separated from each other as Figure 6bare separated from each other as shown. One or more annular movable doors 222 continuously block a part of the inner cavity of the annular fixed door body 21 from the outside to the inside in a direction away from the annular fixed door body 21, and the circular closing door 221 blocks the remaining part of the inner cavity of the annular fixed door body 21.

[0061] If, as Figure 7 shown, the door opening mechanism 22 only includes one annular movable door 222, which is arranged between the annular fixed door body 21 and the circular closing door 221 and can block a part of the cavity inside the annular fixed door body 21. Therefore, the inner diameter of the annular movable door 222 is less than the inner diameter The outer diameter Φ1 of the annular movable door 222 is less than the outer diameter Φ2 of the annular fixed door body 21 and less than the inner diameter of the annular fixed door body 21

[0062] If, as Figure 3 and Figure 4 shown, the door opening mechanism 22 only includes two or more annular movable doors 222, hereinafter referred to as "multiple annular movable doors 222". Since the multiple annular movable doors 222 continuously block a part of the inner cavity of the annular fixed door body 21 from the outside to the inside in a direction away from the annular fixed door body 21, the circular closing door 221 closes the remaining cavity inside the annular fixed door body 21. Therefore, the outer diameter Φ1 and the inner diameter of the multiple annular movable doors 222 decrease in sequence in a direction away from the annular fixed door body 21. Among two adjacent annular movable doors 222, the outer diameter of the annular movable door 222 located on the outer side is less than the outer diameter of the annular movable door 222 located on the inner side and greater than the inner diameter of the annular movable door 222 located on the inner side. The inner diameter of the annular movable door 222 located on the outer side is less than the inner diameter of the annular movable door 222 located on the inner side. The above-mentioned "inner side" refers to the side close to the annular fixed door body 21, and the "outer side" refers to the side away from the annular fixed door body 21. And, the outer diameter Φ1 of the annular movable door 222 adjacent to the annular fixed door body 21 is less than the outer diameter Φ2 of the annular fixed door body 21 and greater than the inner diameter of the annular fixed door body 21 The inner diameter of the annular movable door 222 adjacent to the annular fixed door body 21 correspondingly is less than the inner diameter of the annular fixed door body 21

[0063] The second driving device 23 is in transmission connection with the door opening mechanism 22. The second driving device 23 can drive the two movable door bodies 2221 of the multiple annular movable doors 222 in the door opening mechanism 22, and the two closed door plates 2211 of the circular closed door 221 to move in a direction away from each other, so as to open the annular fixed door body 21; or drive the two movable door bodies 2221 of the multiple annular movable doors 222 in the door opening mechanism 22, and the two closed door plates 2211 of the circular closed door 221 to move in a direction close to each other, so as to close the annular fixed door body 21. The partition door 20 can close the annular fixed door body 21 together with one or more annular movable doors 222 and the circular closed door 221, and the multi-layer door body closed structure ensures the closed reliability of the partition door 20. In addition, the space occupied by the partition door 20 in the furnace chamber 10S when switching between opening and closing is also small, and the vacuum furnace 100 has a compact structure and a small volume.

[0064] Based on the structure of the partition door 20, in some embodiments of the present application, such as Figure 3 As shown, a set of the door opening mechanism 22 is provided on one axial side of the annular fixed door body 21 .

[0065] In other embodiments of the present application, Figure 8 As shown, a group of the door opening mechanisms 22 are respectively provided on both axial sides of the annular fixed door body 21, which is suitable for application scenarios with high sealing requirements.

[0066] It should be noted that, in some embodiments, the second driving device 23 may include: Figure 1 The driving motor 231 and the transmission shaft 232 are shown, and the driving motor 231 is in driving connection with the transmission shaft 232 , and the transmission shaft 232 is in driving connection with two movable door bodies 2221 of the plurality of annular movable doors 222 , and two closed door panels 2211 of the circular closed door 221 .

[0067] Furthermore, in some embodiments of the present application, Figure 9 As shown, the partition door 20 further includes a plurality of guide structures 50, which are respectively arranged between adjacent annular movable doors 222 and annular fixed door bodies 21, and between adjacent annular movable doors 222 and circular closed doors 221. The guide structures 50 can guide the opening and closing process of the annular movable doors 222 and the circular closed doors 221, so that the movement process of the annular movable doors 222 and the circular closed doors 221 is smoother.

[0068] It can be understood that for the door opening mechanism 22 including two or more annular movable doors 222, as Figure 9As shown, the above guiding structure 50 is also provided between two adjacent annular movable doors 222. Moreover, the guiding structures 50 between the adjacent annular movable doors 222 and the annular fixed door body 21, the guiding structures 50 between the adjacent annular movable doors 222 and the circular closing door 221, and the guiding structures 50 between two adjacent annular movable doors 222 may be the same or different, and the present application does not limit this. The following takes the guiding structures 50 between the adjacent annular movable doors 222 and the annular fixed door body 21, the guiding structures 50 between the adjacent annular movable doors 222 and the circular closing door 221, and the guiding structures 50 between two adjacent annular movable doors 222 being the same as an example, and takes the guiding structure 50 between the adjacent annular movable doors 222 and the annular fixed door body 21 for illustration.

[0069] Exemplarily, as Figure 9 shown, the guiding structure 50 may include a plurality of guide rails 51 and a plurality of guide posts 52, and the number of guide rails 51 and the number of guide posts 52 may be equal. For example, the number of guide rails 51 and the number of guide posts 52 in the guiding structure 50 are both 4 - 8. Taking the guiding structure 50 including four guide rails 51 and four guide posts 52 as an example, the four guide rails 51 are arranged at intervals on the annular fixed door body 21 and respectively correspond to two of the movable door bodies 2221 in the annular movable door 222. For example, two guide rails 51 face one of the movable door bodies 2221 in the annular movable door 222, and the other two guide rails 51 correspond to the other movable door body 2221 in the annular movable door 222. The four guide rails 51 all extend along the radial direction of the annular fixed door body 21. Moreover, the four guide posts 52 are respectively arranged on two of the movable door bodies 2221 in the annular movable door 222 and respectively correspond to the four guide rails 51. The four guide rails 51 are located on the surface of the annular movable door 222 close to the annular fixed door body 21. The four guide posts 52 are respectively slidably connected to the four guide rails 51. Thus, guiding during the process of the two movable door bodies 2221 in the annular movable door 222 being spliced or separated from each other is achieved. It can be understood that the positions of the above guide rails 51 and guide posts 52 can also be interchanged. That is, the four guide rails 51 are respectively arranged on two of the movable door bodies 2221 in the annular movable door 222, and the four guide posts 52 are arranged at positions on the annular fixed door body 21 corresponding to the four guide rails 51.

[0070] The above mainly describes the structure in the vacuum furnace 100 related to the furnace chamber 1000 for transporting and loading workpieces to be processed. For the furnace body 10 in the vacuum furnace 100, the structure in the furnace body 10 that, in addition to separating the three heating and heat preservation bins 101S through the partition door 20, closes the sides of the degreasing bin 1011 and the heat treatment bin 1013 far from the sintering bin 1012 can be a part of the furnace body 10. Based on this, in some embodiments of the present application, as Figure 1As shown in the figure, the above-mentioned furnace body 10 includes a first furnace door 11, an intermediate furnace body 12 and a second furnace door 13, and the first furnace door 11, the intermediate furnace body 12 and the second furnace door 13 are connected in sequence. Among them, the degreasing chamber 1011, the sintering chamber 1012 and the heat treatment chamber 1013 are all located in the intermediate furnace body 12. The intermediate furnace body 12 has a first opening 121 and a second opening 122. The first opening 121 is communicated with the degreasing chamber 1011, and the second opening 122 is communicated with the heat treatment chamber 1013. The first furnace door 11 is used to close or open the first opening 121. The second furnace door 13 is used to close or open the second opening 122. Thus, the furnace chamber 1000 loaded with the workpiece to be processed is loaded into the degreasing chamber 1011 through the first opening 121 by the first furnace door 11 to realize feeding. The furnace chamber 1000 after the heat treatment of the workpiece is taken out from the heat treatment chamber 1013 through the second opening 122 by the second furnace door 13 to realize discharging.

[0071] In addition, in the heat treatment process of the workpiece, in addition to heating, when the vacuum furnace 100 performs the heat treatment process, the workpiece also needs to be cooled down. And when the vacuum furnace 100 continuously performs the degreasing process, it is necessary to cool down the degreasing chamber 1011 before another workpiece to be processed enters the degreasing chamber 1011. Therefore, in some embodiments of the present application, the above-mentioned vacuum furnace 100 further includes a first refrigeration device 60 and a second refrigeration device 70. The first refrigeration device 60 can be arranged on the first furnace door 11 of the furnace body 10 and is used to refrigerate the degreasing chamber 1011. The second refrigeration device 70 can be arranged on the second furnace door 13 of the furnace body 10 and is used to refrigerate the heat treatment chamber 1013. Thus, forced refrigeration of the degreasing chamber 1011 and forced refrigeration of the heat treatment chamber 1013 are realized. Among them, the structures of the first refrigeration device 60 and the second refrigeration device 70 can be the same or different, and the present application does not limit this.

[0072] For example, in some embodiments of the present application, the structures of the first refrigeration device 60 and the second refrigeration device 70 are the same. The first refrigeration device 60 includes a first refrigeration pipeline (not shown in the figure), a first strong cooling fan 61 and a first heat exchanger 62. Among them, the first refrigeration pipeline is communicated with the air inlet of the first strong cooling fan 61 ( Figure 1The arrow at the first strong cooling fan 61 indicates the inlet direction of the refrigerating gas). The first refrigeration pipeline can also be connected to a storage device storing a refrigerating gas (such as a low-temperature inert protective gas). The first strong cooling fan 61 can be installed on the first furnace door 11 of the furnace body 10, and the air outlet of the first strong cooling fan 61 can be connected to the degreasing chamber 1011. The first heat exchanger 62 is installed in the furnace chamber 10S in the area connected to the degreasing chamber 1011. The first strong cooling fan 61 is used to introduce the refrigerating gas in the first refrigeration pipeline into the degreasing chamber 1011, and exchange heat with the gas in the degreasing chamber 1011 through the first heat exchanger 62 to achieve refrigeration of the degreasing chamber 1011. The first heat exchanger 62 can increase the heat exchange contact area between the high-temperature gas in the degreasing chamber 1011 and the refrigerating gas introduced by the first strong cooling fan 61.

[0073] The above-mentioned second refrigeration device 70 includes a second refrigeration pipeline (not shown in the figure), a second strong cooling fan 71 and a second heat exchanger 72. Among them, the second refrigeration pipeline is connected to the air inlet of the second strong cooling fan 71 ( Figure 1 The arrow at the second strong cooling fan 71 indicates the inlet direction of the refrigerating gas). The second refrigeration pipeline can also be connected to a storage device storing a refrigerating gas (such as a low-temperature inert protective gas). The second strong cooling fan 71 can be installed on the second furnace door 12 of the furnace body 10, and the air outlet of the second strong cooling fan 71 can be connected to the heat treatment chamber 1013. The second heat exchanger 72 is installed in the furnace chamber 10S in the area connected to the heat treatment chamber 1013. The second strong cooling fan 71 is used to introduce the refrigerating gas in the second refrigeration pipeline into the heat treatment chamber 1013, and exchange heat with the gas in the heat treatment chamber 1013 through the second heat exchanger 72 to achieve refrigeration of the heat treatment chamber 1013. The second heat exchanger 72 can increase the heat exchange contact area between the high-temperature gas in the heat treatment chamber 1013 and the refrigerating gas introduced by the second strong cooling fan 71. The structure of the first refrigeration device 60 and the refrigeration effect of the second refrigeration device 70 are both good.

[0074] Among them, the specific structures of the above-mentioned first furnace door 11 and second furnace door 13 can be various. For example, Figure 1As shown, the above-mentioned first furnace door 11 includes a first outer furnace cover 111 and a first inner cover plate 112. Among them, the first outer furnace cover 111 is movably connected to the first inner cover plate 112 and is connected to the intermediate furnace body 12. The first inner cover plate 112 can cover the first opening 121 of the intermediate furnace body 12 or move away from the first opening 121 to close or open the first opening 121. A first buffer chamber 110 is formed between the first outer furnace cover 111 and the first inner cover plate 112. The above-mentioned first refrigeration device 60 is installed on the first outer furnace cover 111 and is communicated with the first buffer chamber 110. The above-mentioned first heat exchanger 62 is installed in the first buffer chamber 110. Thus, when the first inner cover plate 112 moves away from the first opening 121 and the first refrigeration device 60 is turned on, the degreasing chamber 1011 can be refrigerated.

[0075] The structure of the above-mentioned second furnace door 13 may be the same as or different from that of the first furnace door 11, and the present application does not limit this. In some embodiments, as Figure 1 As shown, the above-mentioned second furnace door 13 includes a second outer furnace cover 131 and a second inner cover plate 132. Among them, the second outer furnace cover 131 is movably connected to the second inner cover plate 132 and is connected to the intermediate furnace body 12. The second inner cover plate 132 can cover the second opening 122 of the intermediate furnace body 12 or move away from the second opening 122 to close or open the second opening 122. A second buffer chamber 130 is formed between the second outer furnace cover 131 and the second inner cover plate 132. The above-mentioned second refrigeration device 70 is installed on the second outer furnace cover 131 and is communicated with the second buffer chamber 130. The above-mentioned second heat exchanger 72 is installed in the second buffer chamber 130. Thus, when the second inner cover plate 132 moves away from the second opening 122 and the second refrigeration device 70 is turned on, the heat treatment chamber 1013 can be refrigerated.

[0076] Moreover, some gases such as inert protective gases need to be introduced for assistance in the above-mentioned degreasing process, sintering process and heat treatment process. Therefore, in some embodiments of the present application, as Figure 1 As shown, the above-mentioned vacuum furnace 100 further includes an intake pipeline 80, and the intake pipeline 80 is respectively communicated with the degreasing chamber 1011, the sintering chamber 1012 and the heat treatment chamber 1013. The intake pipeline 80 can introduce the required process gases into the degreasing chamber 1011, the sintering chamber 1012 and the heat treatment chamber 1013. It can be understood that the above-mentioned vacuum furnace 100 further includes an exhaust pipeline 90, and the exhaust pipeline 90 can timely discharge the gases in the heating and insulation chamber 101S.

[0077] Based on the above structure, in some embodiments of the present application, as Figure 1 As shown, the above-mentioned intake pipeline 80 includes a main intake pipe 81 and three or more intake sub-pipes 82. Figure 1The air intake pipe 80 shown includes three air intake sub-pipes 82, and the three air intake sub-pipes 82 respectively connect the main air intake pipe 81 with the degreasing chamber 1011, the sintering chamber 1012, and the heat treatment chamber 1013. The vacuum furnace 100 also includes a mass flow meter 801 and a control valve (not shown in the figure). The number of mass flow meters 801 can be three or more, and the number of control valves can also be three or more. At least one mass flow meter 801 and a control valve are provided on each air intake sub-pipe 82. Taking the vacuum furnace 100 also including three mass flow meters 801 and three control valves as an example, the three mass flow meters 801 are arranged on the three air intake sub-pipes 82 in a one-to-one correspondence, and the three control valves are arranged on the three air intake sub-pipes 82 in a one-to-one correspondence. Each air intake sub-pipe 82 can be flow detected by a separate mass flow meter 801, and flow controlled by a separate control valve. Thus, the different gas flow requirements of the degreasing (heat removal) process, the sintering process and the heat treatment process are met. The control valve can be specifically a proportional valve, and the flow control is more precise.

[0078] In addition, degreasing volatiles are generated in the above-mentioned thermal degreasing process, and the gas cannot be directly discharged through the gas outlet pipe 90. Therefore, in some embodiments of the present application, the above-mentioned vacuum furnace 100 further includes a wax replenisher (not shown in the figure), and the wax replenisher is connected to the degreasing bin 1011. The wax replenisher can collect the degreasing volatiles in the degreasing bin 1011 to avoid direct discharge and pollution of the environment.

[0079] According to the structure of the vacuum furnace 100, when heat treatment is performed on a workpiece to be processed, the working process of the vacuum furnace 100 of the embodiment of the present application includes:

[0080] S100: The furnace 1000 loaded with the workpiece to be processed is placed into the degreasing chamber 1011 through the first furnace door 11. At this time, the two partition doors 20 and the second furnace door 13 are both kept closed.

[0081] S200: Close the first furnace door 11. First, turn on the mechanical pump in the vacuum pumping device to evacuate the degreasing chamber 1011 so that the vacuum degree of the degreasing chamber 1011 reaches 0.5-1KPa. Then, turn on the Roots pump in the vacuum pumping device to continue to evacuate the degreasing chamber 1011 so that the vacuum degree of the degreasing chamber 1011 reaches about 0.1KPa. After that, turn on the heating device 2 in the degreasing chamber 1011 to heat the furnace 1000 loaded with the workpieces to be processed in the degreasing chamber 1011. At the same time, the control valve on the air inlet sub-pipe 82 connected to the degreasing chamber 1011 is opened to introduce inert protective gas into the degreasing chamber 1011. When the temperature in the degreasing chamber 1011 reaches the degreasing temperature, the workpieces to be processed in the furnace 1000 can be thermally degreased. The degreasing volatiles generated during the thermal degreasing process are collected in the wax replenisher.

[0082] S300: Before the workpiece completes the degreasing process, turn on the heating device 2 in the sintering chamber 1012 so that the temperature in the sintering chamber 1012 can reach the sintering temperature.

[0083] S400: After the workpiece completes the degreasing process, the second driving device 23 in the first partition door 201 drives the door opening mechanism 22 to open the annular fixed door body 21. The first driving device drives the transmission support column 30 in the degreasing chamber 1011 to rise and lift the furnace chamber 1000, and drives the heat preservation baffle 1b to move into the heat preservation cylinder 1a. Subsequently, the first driving device drives the transmission support column 30 to transfer the furnace chamber 1000 to the sintering chamber 1012.

[0084] S500: The second driving device 23 in the first partition door 201 drives the door opening mechanism 22 to close the annular fixed door body 21. The control valve on the intake sub-pipe 82 connected to the sintering chamber 1012 is opened to introduce an inert protective gas into the sintering chamber 1012.

[0085] S600: Before the workpiece completes the sintering process, turn on the heating device 2 in the heat treatment chamber 1013 so that the temperature in the heat treatment chamber 1013 can be raised to a preset temperature.

[0086] S700: After the workpiece completes the sintering process, the second driving device 23 in the second partition door 202 drives the door opening mechanism 22 to open the annular fixed door body 21. The first driving device drives the transmission support column 30 in the sintering chamber 1012 to rise and lift the furnace chamber 1000, and drives the heat preservation baffle 1b to move into the heat preservation cylinder 1a. Subsequently, the first driving device drives the transmission support column 30 to transfer the furnace chamber 1000 to the heat treatment chamber 1013.

[0087] S800: The second driving device 23 in the second partition door 202 drives the door opening mechanism 22 to close the annular fixed door body 21. The control valve on the intake sub-pipe 82 connected to the heat treatment chamber 1013 is opened to introduce an inert protective gas into the heat treatment chamber 1013.

[0088] S900: After the heat treatment chamber 1013 is insulated for a certain period of time, the second inner cover plate 132 in the second furnace door 13 moves away from the second opening 122 of the middle furnace body 12. The second strong cooling fan 71 in the second refrigeration device 70 is turned on to introduce a refrigerating gas into the heat treatment chamber 1013 for cooling. Then, an inert gas with high flow rate and normal temperature is introduced through the intake sub-pipe 82 communicating with the inside of the heat treatment chamber 1013 to perform gas quenching on the workpiece in the furnace chamber 1000. Subsequently, the same heating and heat preservation operations as the above steps are performed as needed to perform aging treatment on the workpiece.

[0089] S1000: After the aging treatment process of the workpiece is completed, open the second furnace door 13, and unload the furnace chamber 1000 loaded with the workpiece through the second opening 122. The heat treatment process of the workpiece is completed.

[0090] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. A vacuum furnace, characterized in that, Comprising: A furnace body, within which a furnace chamber is formed; the furnace chamber includes at least three heating and heat preservation bins distributed along the axial direction, and the at least three heating and heat preservation bins include a degreasing bin, a sintering bin, and a heat treatment bin distributed in sequence; A plurality of partition doors, one partition door separating the degreasing bin from the sintering bin, and another partition door separating the sintering bin from the heat treatment bin; A vacuum pumping device, which is respectively communicated with the degreasing bin, the sintering bin, and the heat treatment bin.

2. The vacuum furnace according to claim 1, wherein, Any one of the heating and heat preservation bins includes a heat preservation cylinder and a heating device. The heat preservation cylinder is sleeved within the furnace body, and a furnace chamber installation cavity is formed within the heat preservation cylinder; the heating device is arranged within the furnace chamber installation cavity and is used for heating the workpiece to be processed within the furnace chamber installation cavity; The length of the furnace chamber installation cavity in the sintering bin is more than twice the length of the furnace chamber installation cavity in the degreasing bin and / or more than twice the length of the furnace chamber installation cavity in the heat treatment bin.

3. The vacuum furnace according to claim 2, wherein The vacuum furnace further includes: A plurality of transmission support columns, the first ends of the plurality of transmission support columns are respectively inserted into the heat preservation cylinders of the three heating and heat preservation bins, and at least one of the transmission support columns is inserted into any one of the heat preservation cylinders; the first end of the transmission support column is used for supporting the furnace chamber loaded with the workpiece to be processed within the heat preservation cylinder; A first driving device, which is in transmission connection with the plurality of transmission support columns, and the first driving device is used for driving the transmission support column within any one of the heat preservation cylinders to move the furnace chamber into the furnace chamber installation cavity of another adjacent heat preservation cylinder.

4. The vacuum furnace according to claim 3, characterized in that, The heat preservation cylinder includes: A heat preservation cylinder body, the barrel wall of which extending along the axial direction is provided with a notch; A heat preservation baffle, the shape of which matches the notch; the transmission support column is hermetically connected to the heat preservation baffle; the heat preservation baffle is configured to: be driven by the transmission support column to close the notch or move into the heat preservation cylinder body.

5. The vacuum furnace according to claim 3 or 4, characterized in that, The heating devices are distributed in a circumferential direction within the heat preservation cylinder, and the heating devices are provided with avoidance openings for avoiding the transmission support columns.

6. The vacuum furnace according to claim 4, characterized in that, The vacuum furnace further includes: A heat insulation device, which is located outside the heat preservation cylinder and is arranged opposite to the heat preservation baffle; the outer periphery of the projection of the heat insulation device on the heat preservation cylinder is located outside the notch of the heat preservation cylinder body.

7. The vacuum furnace according to any one of claims 1-6, characterized in that, The partition door includes: An annular fixed door body, which is fixedly arranged within the inner wall of the furnace body and is arranged along the radial direction of the furnace chamber; A door opening mechanism, the door opening mechanism comprises at least one annular movable door and a circular closed door both arranged along the radial direction of the furnace, the at least one annular movable door is arranged between the annular fixed door body and the circular cover plate, and the at least one annular movable door sequentially and continuously blocks part of the inner cavity of the annular fixed door body from the outside to the inside in a direction away from the annular fixed door body; the circular closed door blocks the remaining part of the inner cavity of the annular fixed door body; the annular movable door comprises two semicircular movable door bodies, and the two movable door bodies can be spliced ​​or separated; the circular closed door comprises two semicircular closed door panels, and the two closed door panels can be spliced ​​or separated; A second driving device, which is in driving connection with the door opening mechanism; the second driving device is used for driving the two movable door bodies of the at least one annular movable door and the two closed door plates of the circular closed door to move in directions away from each other so as to open the annular fixed door body; or, driving the two movable door bodies of the at least one annular movable door and the two closed door plates of the circular closed door to move in directions approaching each other so as to close the annular fixed door body.

8. The vacuum furnace according to claim 7, wherein The partition door also includes: A plurality of guide structures are provided, wherein the plurality of guide structures are respectively arranged between the adjacent annular movable doors and the annular fixed door bodies, and between the adjacent annular movable doors and the circular closed doors.

9. The vacuum furnace according to any one of claims 1-8, characterized in that, The vacuum furnace also includes: a first refrigeration device, which is disposed on the furnace body and is used to refrigerate the degreasing bin; A second refrigeration device is disposed on the furnace body and is used to refrigerate the heat treatment chamber.

10. The vacuum furnace according to claim 9, characterized in that, The first refrigeration device includes a first refrigeration pipeline, a first forced cooling fan and a first heat exchanger, the first refrigeration pipeline is connected to the air inlet of the first forced cooling fan, the first forced cooling fan is installed on the furnace body, and the air outlet of the first forced cooling fan is connected to the degreasing bin, and the first heat exchanger is installed in the area in the furnace cavity that is connected to the degreasing bin; the first forced cooling fan is used to introduce the refrigerant gas in the first refrigeration pipeline into the degreasing bin, and exchange heat with the gas in the degreasing bin through the first heat exchanger; And / or, the second refrigeration device includes a second refrigeration pipe, a second forced cooling fan and a second heat exchanger, the second refrigeration pipe is connected to the air inlet of the second forced cooling fan, the second forced cooling fan is installed on the furnace body, and the air outlet of the second forced cooling fan is connected to the heat treatment chamber, and the second heat exchanger is installed in the area of ​​the furnace cavity that is connected to the degreasing chamber; the second forced cooling fan is used to introduce the refrigerant gas in the second refrigeration pipe into the heat treatment chamber, and exchange heat with the gas in the heat treatment chamber through the second heat exchanger.

11. The vacuum furnace according to any one of claims 1 to 10, characterized in that, The vacuum furnace also includes: An air intake pipeline is connected to the degreasing chamber, the sintering chamber, and the heat treatment chamber respectively.

12. The vacuum furnace according to claim 11, characterized in that, The intake pipeline includes a main intake pipe and at least three intake sub-pipes, and the at least three intake sub-pipes connect the main intake pipe with the degreasing chamber, the sintering chamber, and the heat treatment chamber; The vacuum furnace further includes at least three mass flow meters and at least three control valves. The at least three mass flow meters are respectively arranged on the at least three intake sub-pipes, and the at least three control valves are respectively arranged on the at least three intake sub-pipes. And at least one of the mass flow meters and at least one of the control valves are provided on any one of the intake sub-pipes.

13. The vacuum furnace according to any one of claims 1 to 12, characterized in that, The vacuum furnace further includes: A wax replenisher, which is connected to the degreasing chamber and is used for collecting the degreasing volatiles in the degreasing chamber.

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