Vacuum sintering furnace

Abstract

The utility model discloses a vacuum sintering furnace which comprises a furnace shell, a first isolation valve, a material moving device and a heating chamber. The first isolation valve is connected with a front flange of the furnace shell; the heating chamber is arranged in the furnace shell and comprises a movable bottom plate assembly; the bottom plate assembly comprises a sintering material box support, a heat insulation screen and a bottom plate shell, rolling wheels are arranged on the bottom plate shell, and the bottom plate assembly can move along rails on the inner wall of the furnace shell through the rolling wheels; the material moving device comprises a moving rod, a sealing assembly and a transmission device; the transmission device is arranged outside the furnace shell, the sealing assembly is connected with the furnace shell, and the transmission device drives the moving rod to penetrate through the sealing assembly to enter the furnace shell. The moving rod is connected with the bottom plate assembly and drives the bottom plate assembly to move. After the first isolation valve is opened, the bottom plate assembly can move to the outside of the vacuum sintering furnace. The vacuum sintering furnace can be suitable for a highly automatic and intelligent rare earth permanent magnet intelligent production line.

Description

Technical Field

[0001] This utility model belongs to the field of advanced equipment, and specifically relates to a vacuum sintering furnace for vacuum sintering of rare earth permanent magnet materials. Background Technology

[0002] Rare earth elements are a collective term for 17 elements, which are mixed together in the form of oxides. Neodymium iron boron rare earth permanent magnets mainly use light rare earth elements such as praseodymium and neodymium, and heavy rare earth elements such as dysprosium and terbium. Praseodymium and neodymium account for about 20% of the total rare earth elements, while heavy rare earth elements such as dysprosium and terbium account for less than 5%. Light rare earth elements such as lanthanum and cerium, which account for 70% of the total rare earth elements, are not used, and the supply of heavy rare earth elements such as dysprosium and terbium is tight. The application of rare earth resources is extremely unbalanced, resulting in a great waste of rare earth resources.

[0003] The industrial-scale preparation of rare-earth permanent magnet materials generally employs powder metallurgy technology. First, raw materials are processed into rare-earth permanent magnet alloys. Then, these alloys are pulverized into 3-5 μm powders, oriented and shaped under a magnetic field, removed, sealed, isostatically pressed, and finally vacuum sintered to obtain the rare-earth permanent magnet sintered blank, i.e., the rare-earth permanent magnet material. Rare-earth permanent magnet powders are highly susceptible to oxidation and can spontaneously combust in the atmosphere; therefore, they must be isolated from the atmosphere during the production process. Oxidation during production has consistently hampered industry development and severely impacted product consistency. Currently, the magnetic field presses and vacuum sintering furnaces used in the industry are mostly manufactured by different companies, resulting in poor production line compatibility. The process from molding alloy powder into compacts to sintering blanks largely requires manual operation. This includes material preparation, placement and boxing, stacking the boxes for loading into the furnace, transporting materials between processes, and unloading the sintered blanks. This presents several problems, including the risk of material oxidation due to exposure to the external environment during manual handling, which can hinder further improvement of rare earth permanent magnet material performance. Furthermore, manual operation not only reduces production efficiency, wastes manpower, and increases production costs, but also affects product quality stability due to the inherent uncertainties of manual operation, leading to a certain defect rate. Additionally, after the vacuum sintering process, the stacked boxes need to be laid flat in layers before the sintered blanks can be removed. Since the temperature of the sintered blanks when exiting the furnace is typically between 50-200℃, this adds considerable inconvenience to handling the boxes and the blanks within them.

[0004] Therefore, there is an urgent need to develop a vacuum sintering furnace that is more adaptable to production lines and has a higher degree of automation to change this situation in the industry. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a vacuum sintering furnace for manufacturing high-quality rare earth permanent magnet materials. This vacuum sintering furnace is applicable to a highly automated and intelligent rare earth permanent magnet intelligent production line.

[0006] The vacuum sintering furnace includes a furnace shell, a first isolation valve, a material moving device, a heating chamber, and a vacuum system. The vacuum system is connected to the furnace shell and is used to evacuate the furnace shell. The first isolation valve is connected to the front flange of the furnace shell. The heating chamber is located inside the furnace shell and includes a movable bottom plate assembly. The bottom plate assembly includes a sintering material box support, a heat insulation screen, and a bottom plate outer shell. Rollers are installed on the bottom plate outer shell, and the bottom plate assembly can move along a track on the inner wall of the furnace shell via the rollers. The material moving device includes a moving rod, a sealing assembly, and a transmission device. The transmission device is located outside the furnace shell, and the sealing assembly is connected to the furnace shell. The transmission device drives the moving rod through the sealing assembly into the interior of the furnace shell. The moving rod is connected to the bottom plate assembly, driving the bottom plate assembly to move. A heater is installed inside the heating chamber.

[0007] The base plate assembly also includes a heater, which is mounted on a heat insulation screen; the material moving device has two moving rods, and the moving rods are equipped with electrodes that energize the heater and are connected to cooling water.

[0008] The vacuum sintering furnace also includes an air-cooled heat exchange system and a gas filling system; the air-cooled heat exchange system is located at the rear of the furnace shell, and the air inlet pipe of the air-cooled heat exchange system is connected to the furnace shell; the air-cooled heat exchange system includes a cooling fan and a heat exchanger; the gas filling system includes a gas filling valve; after heating is completed, the gas filling valve is opened to fill the vacuum sintering furnace with protective gas, and the cooling fan is started when the pressure inside the furnace reaches the set value.

[0009] In a preferred embodiment, the vacuum sintering furnace has a horizontal structure with a water-cooled jacket on the furnace shell. The vacuum sintering furnace also includes a cooling system that provides cooling to the furnace shell.

[0010] The heating chamber also includes two side plate assemblies, located on the left and right sides of the heating chamber respectively. The exhaust pipe of the air-cooled heat exchange system splits into two pipelines before entering the furnace shell, each pipeline equipped with a valve. These pipelines pass through the furnace shell and connect to the two side plate assemblies of the heating chamber. Each side plate assembly includes a side plate shell, a heat insulation screen, and nozzles. The nozzles are fixed to the side plate shell and extend through the heat insulation screen of the side plate assembly into the heating chamber. The two valves open and close simultaneously or alternately. Pipes are located on the outer side of the side plate assemblies, connecting to the nozzles and pipelines. Gas flowing from the exhaust pipe of the air-cooled heat exchange system is injected into the heating chamber through the nozzles.

[0011] The heating chamber also includes a front cover assembly and an upper plate assembly.

[0012] After the first isolation valve is opened, the base plate assembly can be moved to the outside of the vacuum sintering furnace; a movable conveyor box is provided outside the vacuum sintering furnace; the vacuum sintering furnace can connect with the conveyor box located outside the vacuum sintering furnace through the first isolation valve; after the vacuum sintering furnace connects with the conveyor box, the base plate assembly moves into the conveyor box to carry the sintering box containing the pressed blank, and then carries the sintering box back into the vacuum sintering furnace. Then, the conveyor box and the vacuum sintering furnace separate, and the vacuum sintering furnace performs the vacuum sintering process.

[0013] After the vacuum sintering process is completed, the vacuum sintering furnace is connected to the conveyor box, and the sintering material box containing the sintered blanks is transferred from the vacuum sintering furnace to the conveyor box through the bottom plate assembly. Before and after the vacuum sintering furnace and the conveyor box are connected, the atmosphere in the conveyor box and the vacuum sintering furnace is kept isolated from the atmosphere.

[0014] In one embodiment of this utility model, the vacuum system of the vacuum sintering furnace includes a mechanical vacuum pump that directly exhausts to the atmosphere and a Roots vacuum pump that further enhances the vacuum level inside the furnace.

[0015] In a preferred embodiment of this invention, the vacuum sintering furnace further includes a sintering box opening device and an opening assembly; sintering boxes are placed on the sintering box support; the opening assembly is located inside the heater and distributed on both sides of the sintering boxes; the sintering box opening device is located at the top of the vacuum furnace shell, and a guide shaft passes through the vacuum furnace shell and the insulation screen of the heating chamber and connects to the opening assembly; the sintering box opening device can drive the guide shaft to move the opening assembly up and down. When the vacuum sintering furnace is working, the opening assembly drives the lids of the sintering boxes loaded in the vacuum sintering furnace to open or close simultaneously. There are more than three layers of sintering boxes loaded in the furnace, and each layer of sintering boxes has more than one lid.

[0016] In one embodiment, the vacuum sintering furnace further includes a conveying hopper; the conveying hopper includes a conveying hopper housing, a hopper clamping and lifting device, a longitudinal moving device, a transverse moving device, and a second isolation valve; the second isolation valve is connected to the conveying hopper housing; the conveying hopper housing is mounted on the transverse moving device, and the longitudinal moving device drives the conveying hopper housing, together with the second isolation valve, to move on the transverse moving device; the conveying hopper carrying multi-layer sintering hoppers containing pressed blanks can move to the opposite side of the vacuum sintering furnace and dock with it, open the first isolation valve and the second isolation valve, and convey the multi-layer sintering hoppers in the conveying hopper into the vacuum sintering furnace, then close the first isolation valve and the second isolation valve, separating the conveying hopper from the vacuum sintering furnace; after the vacuum sintering process of the vacuum sintering furnace is completed, the conveying hopper and the vacuum sintering furnace dock again, open the first isolation valve and the second isolation valve, convey the sintering hoppers containing sintered blanks into the conveying hopper, then close the first isolation valve and the second isolation valve, separating the conveying hopper from the vacuum sintering furnace.

[0017] This utility model also relates to a rare earth permanent magnet intelligent production line, which includes an automatic magnetic field press, a magnetic block conveying device, a boxing box, a conveying bin, and the aforementioned vacuum sintering furnace. There are two or more automatic magnetic field presses arranged side-by-side. One end of each automatic magnetic field press is connected to the side of the magnetic block conveying device, and one end of the magnetic block conveying device is connected to the boxing box. The automatic magnetic field press, the magnetic block conveying device, and the boxing box form a sealed space filled with protective gas. The automatic magnetic field press presses rare earth alloy powder into compacts, which are then conveyed to a conveyor belt located within the magnetic block conveying device, and the compacts are then conveyed to the boxing box via the conveyor belt. The magnetic block conveying device serves as a common conveying channel for the automatic magnetic field presses, conveying the compacts pressed by each automatic magnetic field press to the boxing box. The boxing box is equipped with a robotic arm that picks up pressed blanks and places them into sintering cassettes placed inside the boxing box. There are two or more vacuum sintering furnaces. The boxing box and the vacuum sintering furnaces are arranged side-by-side. The conveyor cassettes can be moved laterally to opposite sides of the boxing box and the vacuum sintering furnace, and then longitudinally to connect with each furnace. A second isolation valve is installed at one end of the conveyor cassette, and a third isolation valve is installed at one end of the boxing box. After the conveyor cassette connects with the boxing box, the second and third isolation valves are opened, connecting the spaces inside the conveyor cassette and the boxing box. The sintering cassettes can then move between the boxing box and the conveyor cassette. Before separating the boxing box and the conveyor cassette, the second and third isolation valves are closed to ensure both are airtight. The sintering cassettes, containing pressed blanks, are then placed in the sintering cassettes. After the material conveying box separates from the boxing box, it moves to the opposite side of the vacuum sintering furnace and docks with it. After docking, the first and second isolation valves are opened to convey the sintered material box containing the pressed blanks into the vacuum sintering furnace. Then, the material conveying box separates from the vacuum sintering furnace. Before separating the material conveying box from the vacuum sintering furnace, the first and second isolation valves are closed to isolate the atmosphere in both the material conveying box and the vacuum sintering furnace from the atmosphere. After the vacuum sintering process in the vacuum sintering furnace is completed, the sintered material box containing the sintered blanks is conveyed back into the material conveying box through docking with the vacuum sintering furnace. Then, the material conveying box separates from the vacuum sintering furnace. In the rare earth permanent magnet intelligent production line, magnetic field forming and vacuum sintering are automatically realized under nitrogen protection or vacuum conditions to produce rare earth permanent magnet sintered blanks.

[0018] The rare earth permanent magnet intelligent production line also includes a discharge mechanism, which is arranged side by side with the box and vacuum sintering furnace. The conveyor box can be moved laterally to the opposite side of the discharge mechanism, and then connected with the discharge mechanism by moving longitudinally. After connection, the second isolation valve is opened, and the sintered material box in the conveyor box can be conveyed to the discharge mechanism, or the sintered material box on the discharge mechanism can be conveyed to the conveyor box.

[0019] The automatic magnetic field press includes a powder storage device, an automatic powder loading device, a powder loading box, a press frame, an upper pressing head assembly, a mold assembly, a lower pressing head assembly, and electromagnetic orientation poles. The powder storage device is located above the powder loading box. The automatic powder loading device is located inside the powder loading box. Neodymium iron boron alloy powder stored in the powder storage device is quantitatively loaded into the mold cavity of the mold assembly by the automatic powder loading device. The upper pressing head assembly, mold assembly, lower pressing head assembly, and electromagnetic orientation poles are located inside the press frame. The upper and lower pressing head assemblies are respectively located above and below the mold assembly. There are two electromagnetic orientation poles, located on both sides of the mold assembly. The mold assembly, together with the upper and lower pressing head assemblies and the electromagnetic orientation poles, achieves bidirectional pressing of the powder in the mold cavity under magnetic field orientation, pressing the powder into a compact. One side of the press frame is connected to the powder loading box, and the other side is connected to a magnetic block conveying device. The compact is conveyed to the conveyor belt after being ejected from the mold cavity. The automatic magnetic field press also includes an electromagnetic orientation coil, which is fitted around the outside of the electromagnetic orientation poles.

[0020] The magnetic block conveying device includes a conveying device housing; one end of the conveying device housing is connected to a box, and the side is connected to an automatic magnetic press; a sensor is provided near the interface connecting the automatic magnetic press and the conveying device housing to detect whether there is a pressed blank at that position. The sensor is used to control the pressed blanks pressed by different automatic magnetic presses to prevent collisions.

[0021] In a preferred embodiment, the rare earth permanent magnet intelligent production line includes four or more automatic magnetic field presses.

[0022] The boxing box includes a box body and a sintered material box conveying device. One end of the box body is connected to a third isolation valve, and the side is connected to a magnetic block conveying device. The conveyor belt inside the magnetic block conveying device extends into the box body. A robotic arm and the sintered material box conveying device are located inside the box body. The robotic arm picks up the pressed blanks conveyed into the box body and places them into the sintered material boxes on the sintered material box conveying device. After the box body and the conveying box are connected, the sintered material box conveying device can move back and forth within the box body and the conveying box. The sintered material box conveying device can move horizontally or vertically.

[0023] In one embodiment of this invention, the press frame has wheels at its lower part, allowing it to move along the axis formed by the powder box, the press frame, and the magnetic block conveying device. The powder box can also move. When the automatic magnetic press requires maintenance, the press frame can be disconnected from the magnetic block conveying device, and then the press frame and the powder box move away from the magnetic block conveying device. When the automatic magnetic press needs to be restored to its working state after maintenance, the press frame and the powder box move towards the magnetic block conveying device, and the connection between the press frame and the magnetic block conveying device is restored. A fourth isolation valve is provided at the interface connecting the automatic magnetic press to the magnetic block conveying device. When the automatic magnetic press is disconnected from the magnetic block conveying device, the fourth isolation valve must be closed first to ensure that the magnetic block conveying device is airtight and to maintain the protective gas atmosphere in the sealed space formed by the magnetic block conveying device, the box, and the automatic magnetic press in operation. Maintenance of the automatic magnetic press includes mold replacement and overhaul.

[0024] The magnetic block conveying device serves as a common conveying channel for the automatic magnetic field presses, transporting the pressed blanks from each press to the packaging box. Even if an automatic magnetic field press undergoes maintenance or resumes operation after maintenance, the airtightness of the magnetic block conveying device remains unaffected. It can still function as a common conveying channel to automatically transport pressed blanks to other automatic magnetic field presses, ensuring the normal operation of the rare earth permanent magnet intelligent production line.

[0025] The discharge mechanism includes a material picking device, a fixed transfer assembly, a moving roller assembly, and a fixed roller assembly. The material picking device is mounted on the fixed transfer assembly, which is also equipped with a conveyor roller. After the conveyor box is connected to the discharge mechanism, the material picking device can reciprocate between the conveyor box and the discharge mechanism. The moving roller assembly is connected to the fixed transfer assembly, or to one or more sets of fixed roller assemblies. During operation, the material picking device enters the conveyor box, takes out the sintered material box, and places it on the conveyor roller of the fixed transfer assembly. The conveyor roller of the fixed transfer assembly then conveys the sintered material box to the moving roller assembly. The moving roller assembly first connects to one set of fixed roller assemblies to convey the sintered material box to this set of fixed roller assemblies. Then, the moving roller assembly connects to another set of fixed roller assemblies carrying empty sintered material boxes to convey the empty sintered material boxes to the moving roller assembly. Finally, the empty sintered material boxes are conveyed into the conveyor box through the moving roller assembly and the material picking device.

[0026] The conveying box includes a conveying box shell, a box clamping and lifting device, a longitudinal moving device, and a transverse moving device; a second isolation valve is connected to the conveying box shell; the conveying box shell is installed on the guide rail of the transverse moving device, and the conveying box shell together with the second isolation valve moves longitudinally on the guide rail of the transverse moving device to realize the docking of the conveying box with the boxing box or with the vacuum sintering furnace.

[0027] After the box and the conveyor box are connected, the reciprocating movement of the sintering box conveyor device in the box and the lifting and lowering of the box clamping lifting device in the conveyor box, together with the movement of the robotic arm, complete the process of automatically loading the pressed billet into the sintering box and automatically stacking the sintering boxes.

[0028] In a preferred embodiment of this utility model, the conveying box further includes a material bed; multiple sintered boxes are arranged in n layers on the material bed, where n≥3. The process of loading the pressed blanks into the sintered boxes and automatically stacking the sintered boxes includes: after the boxing box is connected to the conveying box, the box clamping and lifting device lifts all n layers of empty sintered boxes from the material bed; the sintered box conveying device moves horizontally from the boxing box to the conveying box housing; then, the box clamping and lifting device lowers the n layers of empty sintered boxes onto the sintered box conveying device; then, the box clamping and lifting device lifts (n-1) layers of empty sintered boxes; the sintered box conveying device moves the remaining 1 layer of empty sintered boxes from the conveying box housing to the boxing box; then, the sintered box conveying device moves vertically, loading the pressed blanks into the sintered boxes in the boxing box; and finally, the sintered box conveying device moves the sintered boxes containing the pressed blanks horizontally to the conveying box. Inside the housing, the box holding and lifting device lowers the (n-1) layers of empty sintered boxes onto the sintered box conveying device above the layer of sintered boxes. Then, the box holding and lifting device lifts the (n-2) layers of empty sintered boxes. The sintered box conveying device moves the two layers of sintered boxes, including one layer of empty sintered boxes, from the conveying box housing to the boxing box. In the boxing box, the pressed blanks are loaded into the empty sintered boxes. This process is repeated until all n layers of empty sintered boxes have been loaded with pressed blanks in the boxing box and then moved back to the conveying box housing. Then, the box holding and lifting device lifts the n layers of sintered boxes containing pressed blanks from the sintered box conveying device. The sintered box conveying device returns to the boxing box, and the box holding and lifting device lowers the n layers of sintered boxes onto the material bed.

[0029] In one embodiment of this utility model, the rare earth permanent magnet intelligent production line also includes a glove box; the other end of the conveying device box is connected to the manually discharged glove box, and the glove box includes a glove box body, a fifth isolation valve, a discharge box and a material tray transmission device.

[0030] This utility model also relates to a method for manufacturing rare earth permanent magnet materials, which is implemented using the above-mentioned rare earth permanent magnet intelligent production line. The entire process, from the initial loading of powder into the automatic magnetic field press to the sintering of the pressed blank, is completed under conditions of isolation from the atmosphere. The manufacturing method includes: (1) automatically feeding neodymium iron boron alloy powder from the powder storage device into the mold cavity of the automatic magnetic field press, and automatically ejecting the pressed blank after magnetic orientation and conveying it to the conveyor belt in front of the automatic magnetic field press; (2) the conveyor belt carries the pressed blank into the box located on the side of the automatic magnetic field press, and the pressed blank is placed into the sintering box by the robot arm in the box; (3) docking the conveyor box and the box, opening the first isolation valve and the second isolation valve, and then, through the movement of the sintering box conveying device of the box and the lifting of the box clamping lifting device of the conveyor box, the pressed blank is then... (3) The pressing blanks are loaded into the sintering box and stacked in the conveying box in coordination with the robot arm; (4) After the first isolation valve and the second isolation valve are closed, the conveying box is separated from the boxing box. After the conveying box containing the pressing blanks is separated from the boxing box, it is moved to the vacuum sintering furnace equipped with the third isolation valve. After the conveying box is connected to the vacuum sintering furnace, the third isolation valve and the second isolation valve are opened to convey the sintering box containing the pressing blanks in the conveying box to the vacuum sintering furnace. Then, the conveying box and the vacuum sintering furnace are separated, and the vacuum sintering furnace performs the vacuum sintering process.

[0031] Before separating the conveyor box and the vacuum sintering furnace, close the second and third isolation valves to keep the atmosphere inside the conveyor box and the vacuum sintering furnace isolated from the atmosphere.

[0032] The manufacturing method also includes: after the vacuum sintering process, the conveying box and the vacuum sintering furnace are connected. After opening the third isolation valve and the second isolation valve, the sintering box containing the sintered blank is conveyed into the conveying box. After closing the third isolation valve and the second isolation valve, the conveying box and the vacuum sintering furnace are separated. The conveying box is moved to the front of the discharge mechanism. The second isolation valve is opened to move the sintering box containing the sintered blank in the conveying box to the discharge mechanism. Then, the empty sintering box on the discharge mechanism is conveyed into the conveying box. The conveying box is moved to the front of the boxing box. The conveying box and the boxing box are connected. The empty sintering box is moved from the conveying box to the boxing box, completing the process of magnetic field forming and vacuum sintering of rare earth permanent magnet materials. The automatic magnetic field press, the magnetic block conveying device and the boxing box constitute a closed space, which is filled with protective gas. From the time the pressed blank is loaded into the sintering box until the end of vacuum sintering, the pressed blank is isolated from the atmosphere.

[0033] This manufacturing method does not include the isostatic pressing process.

[0034] In this novel intelligent production line for rare earth permanent magnets, the entire process, from alloy powder to the magnetic field forming and vacuum sintering of rare earth permanent magnet materials into sintered blanks, is automated under nitrogen protection or vacuum conditions. This ensures that the easily oxidized rare earth permanent magnet raw materials are always isolated from the atmospheric environment, which helps reduce the oxygen content in the materials and further improves their performance. Furthermore, the material preparation, placement and packaging, furnace loading, material transportation between processes, and the unloading and removal of sintered blanks are all fully automated. This not only improves production efficiency, saves human resources, and reduces production costs, but also eliminates the uncertainties of manual operation, reduces product defect rates, and improves product quality stability. Under the same raw material composition and manufacturing process parameters, the oxygen content in the rare earth permanent magnet materials manufactured using this invention is reduced by approximately 200 ppm, resulting in a product defect rate reduction of approximately 30% during the process.

[0035] Current vacuum sintering furnaces in the industry generally utilize a glove box structure and rely on manual operation for protective feeding. Furthermore, most employ a forklift mechanism to move materials from the glove box to the material bed of the vacuum sintering furnace. During material movement, the cantilevered forklift exhibits a certain degree of vibration. The inventors discovered that in this production line, because two isolation valves are installed between the vacuum sintering furnace and the conveyor box, if this type of vacuum sintering furnace is still used, the cantilever length of the forklift would need to be increased due to the larger travel distance, easily leading to exacerbated vibration. This vibration can cause micro-defects in the pressed blanks in the sintering box, negatively impacting the quality of the sintered rare earth permanent magnet materials. The vacuum sintering furnace of this invention includes a movable base plate assembly with rollers on its outer shell. The base plate assembly can move along a track on the inner wall of the furnace shell via the rollers. After the vacuum sintering furnace docks with the conveyor box, the base plate assembly moves into the conveyor box to carry the sintering box containing the pressed blanks, and then returns the sintering box to the vacuum sintering furnace. The movable base plate assembly structure ensures smooth transmission and effectively overcomes the aforementioned problems.

[0036] Existing technologies were primarily developed around 2000. Despite numerous improvements since then, the market urgently needs to address the imbalance in rare earth resource utilization and the tight supply of the heavy rare earth elements dysprosium and terbium. Therefore, the applicant has developed a new generation of process and production line equipment technology to overcome the challenges of existing technologies. This application is part of a new technology production line equipment, primarily addressing the following issues:

[0037] 1. Existing technology involves a boxing box in front of each press, and then the boxes filled with pressed billets are conveyed to the boxing box for arrangement. A single batch of pressed billets in a vacuum sintering furnace requires docking with multiple moving boxing boxes, involving multiple gas filling and venting processes. This not only complicates the equipment and increases workload significantly, but also severely increases the oxygen content of the pressed billets. This structure requires human intervention and is not truly automated. This application proposes a conveyor belt that directly carries the pressed billets into the boxing box, where they are uniformly loaded into the sintering boxes. A single docking between the conveyor box and the boxing box completes a single batch in the sintering furnace. This results in lower oxygen content, saves nitrogen, and is simple, reliable, and practical.

[0038] 2. In this invention, the conveyor box connects to the boxing box, and after disconnecting from the boxing box, it connects directly to the vacuum sintering furnace. Empty sintering boxes are returned to the boxing box via the conveyor box, achieving automated operation.

[0039] 3. In existing technology, a carrier 1 interfaces with the magnetic field press, while a carrier 2 interfaces with the boxing container. The interface sizes of carriers 1 and 2 are different, and carrier 1 cannot interface with the glove box of the vacuum sintering furnace. This means that empty sintered material boxes cannot be directly transferred to the magnetic field press. This invention directly transfers the pressed blanks from multiple magnetic field presses to the boxing container, eliminating the need to transfer the sintered material boxes to the magnetic field press. This results in a shorter, simpler process and easier control of oxygen content. The transfer box can directly interface with the boxing container, the vacuum sintering furnace, and the discharge device. After interfaceing with the discharge device, the transfer box transfers the sintered material boxes in layers to the discharge mechanism. The single-layer empty sintered material boxes on the discharge mechanism are then loaded into the transfer box, stacked, and then transferred back to the boxing container to load the pressed blanks, thus completing fully automated operation.

[0040] 4. The carton in the production line involved in this utility model includes a carton shell, a material box moving device, and a material picking mechanism; the material picking mechanism includes a robot arm, which is mounted upside down on the top of the carton and is also equipped with a vision system; the pressed blank is conveyed into the carton, and the robot arm determines when to grab the pressed blank and where to place it. Attached Figure Description

[0041] Figure 1 This is a front view structural schematic diagram of one embodiment of the vacuum sintering furnace in this utility model.

[0042] Figure 2 This is a top view schematic diagram of one embodiment of the vacuum sintering furnace in this utility model.

[0043] Figure 3 This is a side view of one embodiment of the vacuum sintering furnace in this utility model.

[0044] Figure 4 This is a schematic diagram of the structural layout of one embodiment of the rare earth permanent magnet intelligent production line involved in this utility model.

[0045] Figure 5 This is a schematic diagram of one embodiment of the automatic magnetic field press of the rare earth permanent magnet intelligent production line involved in this utility model. Detailed Implementation

[0046] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0047] like Figure 1 , Figure 2 and Figure 3 As shown, the vacuum sintering furnace 01 of this utility model includes a furnace shell 1, a first isolation valve 2, a material moving device 3, a heating chamber 4, and a vacuum system 5; the first isolation valve 2 is connected to the front flange of the furnace shell; the heating chamber 4 is located inside the furnace shell 1 and includes a movable bottom plate assembly 6; the bottom plate assembly 6 includes a sintering material box support 7, a heat insulation screen 8, and a bottom plate outer shell 9, with rollers 10 provided on the bottom plate outer shell 9, allowing the bottom plate assembly 6 to move along a track 11 on the inner wall of the furnace shell via the rollers 10; the material moving device 3 includes a moving rod 12, a sealing assembly 13, and a transmission device 14, with the transmission device 14 located outside the furnace shell 1, the sealing assembly 13 connected to the furnace shell 1, and the transmission device 14 driving the moving rod 12 through the sealing assembly 13 into the interior of the furnace shell 1; the moving rod 12 is connected to the bottom plate assembly 6, driving the bottom plate assembly 6 to move. A heater 15 is provided inside the heating chamber 4.

[0048] The base plate assembly 6 also includes a heater 16, which is mounted on the heat insulation screen 8; the material moving device has two moving rods 12, and the moving rods 12 have electrodes inside that energize the heater 16.

[0049] The vacuum sintering furnace 01 also includes an air-cooled heat exchange system 17 and a gas filling system 18. The air-cooled heat exchange system 17 is located behind the furnace shell 1, and its inlet pipe is connected to the furnace shell 1. The air-cooled heat exchange system includes a cooling fan and a heat exchanger. The gas filling system 18 includes a gas filling valve 19. After heating is completed, the gas filling valve 19 is opened to fill the vacuum sintering furnace with protective gas. When the pressure inside the furnace reaches the set value, the cooling fan is started.

[0050] The heating chamber 4 also includes two side plate assemblies 20, located on the left and right sides of the heating chamber 4 respectively. The exhaust pipe 21 of the air-cooled heat exchange system splits into two pipes 22 before entering the furnace shell. Each pipe 22 is equipped with a valve 23. The pipes 22 pass through the furnace shell 1 and connect to the two side plate assemblies 20 of the heating chamber respectively. The side plate assembly 20 includes a side plate outer shell, a heat insulation screen, and a nozzle 24. The nozzle 24 is fixed to the side plate outer shell and extends through the heat insulation screen of the side plate assembly 20 into the interior of the heating chamber 4. The two valves 23 open and close simultaneously or alternately. A pipe 25 is provided on the outside of the side plate assembly 20, communicating with the nozzle 24 and the pipe 22. Gas flowing from the exhaust pipe 21 of the air-cooled heat exchange system is injected into the interior of the heating chamber 4 through the nozzle 24.

[0051] The heating chamber also includes a front cover assembly and an upper plate assembly.

[0052] In a preferred embodiment, the vacuum sintering furnace has a horizontal structure with a water-cooled jacket on the furnace shell. The vacuum sintering furnace also includes a cooling system that provides cooling to the furnace shell.

[0053] After the first isolation valve 2 is opened, the base plate assembly 6 can be moved to the outside of the vacuum sintering furnace 01. A movable conveyor box 26 is provided outside the vacuum sintering furnace 01, and a second isolation valve 30 is provided at one end of the conveyor box 26. The vacuum sintering furnace 01 can connect with the conveyor box 26 located outside the vacuum sintering furnace through the first isolation valve 2. After the vacuum sintering furnace 01 connects with the conveyor box 26, the first isolation valve 2 and the second isolation valve 30 are opened, and the base plate assembly 6 moves into the conveyor box 26 to carry the sintering material box 27 containing the pressed blank, and then carries the sintering material box 27 back into the vacuum sintering furnace 01. Then, the conveyor box 26 and the vacuum sintering furnace 01 separate, and the vacuum sintering furnace 01 performs the vacuum sintering process. Before the conveyor box 26 and the vacuum sintering furnace 01 separate, the first isolation valve 2 and the second isolation valve 30 are closed.

[0054] After the vacuum sintering process is completed, the vacuum sintering furnace 01 is connected to the conveying box 26, and the sintering material box 27 containing the sintered blank is transferred from the vacuum sintering furnace 01 to the conveying box 26 through the bottom plate assembly 6. Before and after the vacuum sintering furnace 01 is connected to the conveying box 26, the atmosphere in the conveying box 26 and the vacuum sintering furnace 01 is kept isolated from the atmosphere.

[0055] In one embodiment of this utility model, the vacuum system 5 of the vacuum sintering furnace includes a mechanical vacuum pump 28 that directly exhausts to the atmosphere and a Roots vacuum pump 29 that further enhances the vacuum level inside the furnace.

[0056] In a preferred embodiment of the present invention, the vacuum sintering furnace further includes a sintering material box opening device, which includes a synchronous opening adjustment device on the upper part of the furnace shell and an opening component inside the furnace shell. When the vacuum sintering furnace is working, the opening component drives the lids of the sintering material boxes loaded in the vacuum sintering furnace to open or close simultaneously. There are more than 3 layers of sintering material boxes loaded in the furnace, and each layer of sintering material boxes has more than 1 lid.

[0057] This utility model also relates to a rare earth permanent magnet intelligent production line, such as Figure 4 As shown, the rare earth permanent magnet intelligent production line includes an automatic magnetic field press 31, a magnetic block conveying device 32, a packaging box 33, a conveying material box 26, and the aforementioned vacuum sintering furnace 01. In such a way... Figure 4 In the illustrated embodiment, the rare earth permanent magnet intelligent production line includes four vacuum sintering furnaces and four automatic magnetic field presses arranged side by side. One end of each automatic magnetic field press is connected to the side of a magnetic block conveying device 32, and one end of the magnetic block conveying device 32 is connected to a box 33. The automatic magnetic field press 31, the magnetic block conveying device 32, and the box 33 form a sealed space filled with protective gas. The automatic magnetic field press 31 presses the rare earth alloy powder into a compact and then conveys it to a conveyor belt located within the magnetic block conveying device 32, which then transports the compact to the box 33. The magnetic block conveying device 32 serves as a common conveying channel for the automatic magnetic field presses, transporting the compacts pressed by each automatic magnetic field press to the box 33. A robotic arm is installed inside the box, which picks up the compacts and places them into a sintering hopper placed within the box.

[0058] The packaging box 33 and the vacuum sintering furnace 01 are arranged side by side. The conveying box 26 can be moved laterally to the opposite side of the packaging box 33 and the vacuum sintering furnace 01, and then longitudinally to dock with the packaging box 33 and the vacuum sintering furnace 01 respectively. A third isolation valve 34 is provided at one end of the packaging box 33. After the conveying box 26 docks with the packaging box 33, the second isolation valve 30 and the third isolation valve 34 are opened, connecting the space inside the conveying box 26 with the space inside the packaging box 33. Then, the sintering box can move between the packaging box 33 and the conveying box 26. Before the packaging box 33 and the conveying box 26 are separated, the second isolation valve 30 and the third isolation valve 34 are closed to ensure that both the packaging box 33 and the conveying box 26 are sealed and leak-proof.

[0059] After separating from the box 33, the conveyor box 26, which carries the sintering material box containing the pressed blank, moves to the opposite side of the vacuum sintering furnace 01 and docks with it. After docking, the first isolation valve 2 and the second isolation valve 30 are opened to convey the sintering material box containing the pressed blank in the conveyor box 26 into the vacuum sintering furnace 01. Then the conveyor box 26 is separated from the vacuum sintering furnace 01. Before the conveyor box 26 and the vacuum sintering furnace 01 are separated, the first isolation valve 2 and the second isolation valve 30 are closed to isolate the atmosphere in both the conveyor box 26 and the vacuum sintering furnace 01 from the atmosphere.

[0060] After the vacuum sintering process in the vacuum sintering furnace is completed, the sintering material box containing the sintered blank is transferred to the conveying material box through the docking of the conveying material box and the vacuum sintering furnace. Then, the conveying material box and the vacuum sintering furnace are separated. In the rare earth permanent magnet intelligent production line, magnetic field forming and vacuum sintering are automatically realized under nitrogen protection or vacuum conditions to produce rare earth permanent magnet sintered blanks.

[0061] The rare earth permanent magnet intelligent production line also includes a discharge mechanism 35, which is arranged side by side with the packaging box 33 and the vacuum sintering furnace 01. The conveying box 26 can be moved laterally to the opposite side of the discharge mechanism 35, and then moved longitudinally to dock with the discharge mechanism 35. After docking, the second isolation valve 30 is opened, and the sintered material box in the conveying box 26 can be conveyed to the discharge mechanism 35, or the sintered material box on the discharge mechanism 35 can be conveyed to the conveying box 26.

[0062] like Figure 5 As shown, the automatic magnetic field press 31 includes a powder storage device 36, an automatic powder loading device 37, a powder loading box 38, a press frame 39, an upper press head assembly 40, a mold assembly 41, a lower press head assembly 42, and electromagnetic orientation poles 43. The powder storage device 36 is located above the powder loading box 38. The automatic powder loading device 37 is located inside the powder loading box 38. The NdFeB alloy powder stored in the powder storage device 36 is quantitatively loaded into the mold cavity of the mold assembly 41 by the automatic powder loading device 37. The upper press head assembly 40, the mold assembly 41, the lower press head assembly 42, and the electromagnetic orientation poles 43 are located inside the press frame 39. The upper press head assembly 40 and the lower press head assembly 42 are respectively located above and below the mold assembly 41. There are two electromagnetic orientation poles 43, located on both sides of the mold assembly 41. One side of the press frame 39 is connected to the powder loading box 38, and the other side is connected to the magnetic block conveying device 32. A conveyor belt 44 is provided inside the magnetic block conveying device 32.

[0063] The mold assembly, together with the upper and lower pressure head assemblies and the electromagnetic orientation poles, enables bidirectional pressing of the powder within the mold cavity under magnetic field orientation, compressing the powder into a compact. The compact is then ejected from the mold cavity and conveyed onto a conveyor belt.

[0064] The automatic magnetic field press is also equipped with an electromagnetic orientation coil, which is mounted on the outside of the electromagnetic orientation pole.

[0065] exist Figure 5 In the illustrated embodiment, the lower part of the press frame 39 has wheels 45, allowing it to move along the axis formed by the powder hopper 38, the press frame 39, and the magnetic block conveying device 32. Wheels 46 are also provided below the powder hopper 38, allowing it to move as well. A fourth isolation valve 47 is provided at the interface on the magnetic block conveying device 32 that connects to the automatic magnetic field press 31.

[0066] When the automatic magnetic field press requires maintenance, the press frame can be disconnected from the magnetic block conveying device, and then the press frame and powder box can be moved away from the magnetic block conveying device. After maintenance, when the automatic magnetic field press needs to be restored to operation, the press frame and powder box can be moved back towards the magnetic block conveying device, and the connection between the press frame and the magnetic block conveying device is restored. When the automatic magnetic field press is disconnected from the magnetic block conveying device, the fourth isolation valve must first be closed to ensure the magnetic block conveying device is airtight, maintaining a constant protective gas atmosphere within the enclosed space formed by the magnetic block conveying device, the box, and the operating automatic magnetic field press. Maintenance of the automatic magnetic field press includes mold replacement and overhaul.

[0067] The magnetic block conveying device serves as a common conveying channel for the automatic magnetic field presses, transporting the pressed blanks from each press to the packaging box. Even if an automatic magnetic field press undergoes maintenance or resumes operation after maintenance, the airtightness of the magnetic block conveying device remains unaffected. It can still function as a common conveying channel to automatically transport pressed blanks to other automatic magnetic field presses, ensuring the normal operation of the rare earth permanent magnet intelligent production line.

[0068] The magnetic block conveying device includes a conveying device housing; one end of the conveying device housing is connected to a box, and the side is connected to an automatic magnetic press; a sensor is provided near the interface connecting the automatic magnetic press and the conveying device housing to detect whether there is a pressed blank at that position. The sensor is used to control the pressed blanks pressed by different automatic magnetic presses to prevent collisions.

[0069] The boxing box includes a box body and a sintered material box conveying device. One end of the box body is connected to a third isolation valve, and the side is connected to a magnetic block conveying device. The conveyor belt inside the magnetic block conveying device extends into the box body. A robotic arm and the sintered material box conveying device are located inside the box body. The robotic arm picks up the pressed blanks conveyed into the box body and places them into the sintered material boxes on the sintered material box conveying device. After the box body and the conveying box are connected, the sintered material box conveying device can move back and forth within the box body and the conveying box. The sintered material box conveying device can move horizontally or vertically.

[0070] The discharge mechanism includes a material picking device, a fixed transfer assembly, a moving roller assembly, and a fixed roller assembly. The material picking device is mounted on the fixed transfer assembly, which is also equipped with a conveyor roller. After the conveyor box is connected to the discharge mechanism, the material picking device can reciprocate between the conveyor box and the discharge mechanism. The moving roller assembly is connected to the fixed transfer assembly, or to one or more sets of fixed roller assemblies. During operation, the material picking device enters the conveyor box, takes out the sintered material box, and places it on the conveyor roller of the fixed transfer assembly. The conveyor roller of the fixed transfer assembly then conveys the sintered material box to the moving roller assembly. The moving roller assembly first connects to one set of fixed roller assemblies to convey the sintered material box to this set of fixed roller assemblies. Then, the moving roller assembly connects to another set of fixed roller assemblies carrying empty sintered material boxes to convey the empty sintered material boxes to the moving roller assembly. Finally, the empty sintered material boxes are conveyed into the conveyor box through the moving roller assembly and the material picking device.

[0071] like Figure 3 As shown, the conveying hopper 26 includes a conveying hopper housing 48, a hopper clamping and lifting device 49, a longitudinal moving device 50, and a transverse moving device 51; the second isolation valve 30 is connected to the conveying hopper housing 48; the conveying hopper housing 48 is mounted on the guide rail 52 of the transverse moving device, and the conveying hopper housing 48 together with the second isolation valve 30 moves longitudinally on the guide rail 52 of the transverse moving device to realize the connection between the conveying hopper and the hopper box, or with the vacuum sintering furnace.

[0072] After the box and the conveyor box are connected, the reciprocating movement of the sintering box conveyor device in the box and the lifting and lowering of the box clamping lifting device in the conveyor box, together with the movement of the robotic arm, complete the process of automatically loading the pressed billet into the sintering box and automatically stacking the sintering boxes.

[0073] In one embodiment of this utility model, the rare earth permanent magnet intelligent production line also includes a glove box; the other end of the conveying device box is connected to the manually discharged glove box, and the glove box includes a glove box body, a fifth isolation valve, a discharge box and a material tray transmission device.

[0074] This utility model also relates to a method for manufacturing rare earth permanent magnet materials, which is implemented using the above-mentioned rare earth permanent magnet intelligent production line. The entire process from the initial loading of powder into the automatic magnetic field press to the sintering of the pressed blank is completed under conditions of isolation from the atmosphere. The manufacturing method includes: (1) automatically feeding neodymium iron boron alloy powder from the powder storage device into the mold cavity of the automatic magnetic field press, and automatically ejecting the pressed blank after magnetic orientation and conveying it to the conveyor belt in front of the automatic magnetic field press; (2) the conveyor belt carries the pressed blank into the box located on the side of the automatic magnetic field press, and the robot in the box places the pressed blank into the sintering box; (3) docking the conveyor box and the box, opening the first isolation valve and the second isolation valve, and using the movement of the sintering box conveyor device of the box and the lifting of the box clamping lifting device of the conveyor box, and with the help of the robot, loading the pressed blank into the sintering box and stacking it in the conveyor box; (4) After closing the first isolation valve and the second isolation valve, the conveyor box is separated from the boxing box. After the conveyor box containing the sintered material box with the pressed blank is separated from the boxing box, it is moved to the vacuum sintering furnace equipped with the third isolation valve. After the conveyor box is connected to the vacuum sintering furnace, the third isolation valve and the second isolation valve are opened to convey the sintered material box containing the pressed blank in the conveyor box to the vacuum sintering furnace. Then, the conveyor box and the vacuum sintering furnace are separated, and the vacuum sintering furnace performs the vacuum sintering process. Before the conveyor box and the vacuum sintering furnace are separated, the second isolation valve and the third isolation valve are closed to keep the atmosphere in the conveyor box and the vacuum sintering furnace isolated from the atmosphere.

[0075] The manufacturing method further includes: after the vacuum sintering process is completed, the conveying box and the vacuum sintering furnace are connected. After opening the third isolation valve and the second isolation valve, the sintering box containing the sintered blank is conveyed into the conveying box. After closing the third isolation valve and the second isolation valve, the conveying box and the vacuum sintering furnace are separated. The conveying box is moved to the front of the discharge mechanism. The second isolation valve is opened to move the sintering box containing the sintered blank in the conveying box to the discharge mechanism. Then, the empty sintering box on the discharge mechanism is conveyed into the conveying box. The conveying box is moved to the front of the boxing box. The conveying box and the boxing box are connected. The empty sintering box is moved from the conveying box to the boxing box, thus completing the process of magnetic field forming and vacuum sintering of rare earth permanent magnet materials.

[0076] The automatic magnetic field press, magnetic block conveying device, and boxing box form a sealed space filled with protective gas; from the time the compact is loaded into the sintering box until the vacuum sintering is completed, the compact is isolated from the atmosphere.

[0077] This manufacturing method does not include the isostatic pressing process.

Claims

1. A vacuum sintering furnace, characterized in that: The furnace includes a furnace shell, a first isolation valve, a material moving device, a heating chamber, and a vacuum system. The vacuum system is connected to the furnace shell and is used to evacuate the furnace shell. The first isolation valve is connected to the front flange of the furnace shell. The heating chamber is located inside the furnace shell and includes a movable bottom plate assembly. The bottom plate assembly includes a sintering material box support, a heat insulation screen, and a bottom plate outer shell. Rollers are provided on the bottom plate outer shell, and the bottom plate assembly can move along a track on the inner wall of the furnace shell via the rollers. The material moving device includes a moving rod, a sealing assembly, and a transmission device. The transmission device is located outside the furnace shell, and the sealing assembly is connected to the furnace shell. The transmission device drives the moving rod to pass through the sealing assembly and enter the interior of the furnace shell. The moving rod is connected to the bottom plate assembly and drives the bottom plate assembly to move.

2. The vacuum sintering furnace according to claim 1, characterized in that: The base plate assembly also includes a heater, which is mounted on a heat insulation screen; the material moving device has two moving rods, and the moving rods are equipped with electrodes that energize the heater and are connected to cooling water.

3. The vacuum sintering furnace according to claim 1, characterized in that: The vacuum sintering furnace also includes an air-cooled heat exchange system and a gas filling system; the air-cooled heat exchange system is located at the rear of the furnace shell, and the air inlet pipe of the air-cooled heat exchange system is connected to the furnace shell; the air-cooled heat exchange system includes a cooling fan and a heat exchanger; the gas filling system includes a gas filling valve; after heating is completed, the gas filling valve is opened to fill the vacuum sintering furnace with protective gas, and the cooling fan is started when the pressure inside the furnace reaches the set value.

4. The vacuum sintering furnace according to claim 3, characterized in that: The heating chamber also includes two side plate assemblies, located on the left and right sides of the heating chamber respectively; the air outlet pipe of the air-cooled heat exchange system is divided into two pipelines before entering the furnace shell, and each pipeline is equipped with a valve. The pipelines pass through the furnace shell and are connected to the two side plate assemblies of the heating chamber respectively; the side plate assembly includes a side plate shell, a heat insulation screen and a nozzle; the nozzle is fixed on the side plate shell and extends through the heat insulation screen of the side plate assembly into the interior of the heating chamber; the two valves are opened and closed simultaneously or alternately.

5. The vacuum sintering furnace according to claim 1, characterized in that: After the first isolation valve is opened, the base plate assembly can be moved to the outside of the vacuum sintering furnace; a movable conveyor box is provided on the outside of the vacuum sintering furnace. The vacuum sintering furnace can connect with the conveying box through the first isolation valve. After the vacuum sintering furnace connects with the conveying box, the bottom plate assembly moves into the conveying box to carry the sintering box containing the pressed billet, and then carries the sintering box back into the vacuum sintering furnace. Then, the conveying box and the vacuum sintering furnace separate, and the vacuum sintering furnace performs the vacuum sintering process.

6. The vacuum sintering furnace according to claim 1, characterized in that: The vacuum sintering furnace also includes a conveying hopper; the conveying hopper includes a conveying hopper shell, a hopper clamping and lifting device, a longitudinal moving device, a transverse moving device, and a second isolation valve; the second isolation valve is connected to the conveying hopper shell; the conveying hopper shell is mounted on the transverse moving device, and the longitudinal moving device drives the conveying hopper shell, together with the second isolation valve, to move on the transverse moving device; the conveying hopper carrying multi-layer sintering hoppers containing pressed blanks can move to the opposite side of the vacuum sintering furnace and dock with it, open the first and second isolation valves, and convey the multi-layer sintering hoppers in the conveying hopper into the vacuum sintering furnace, then close the first and second isolation valves, and the conveying hopper separates from the vacuum sintering furnace; after the vacuum sintering process of the vacuum sintering furnace is completed, the conveying hopper and the vacuum sintering furnace dock again, open the first and second isolation valves, convey the sintering hoppers containing sintered blanks into the conveying hopper, then close the first and second isolation valves, and the conveying hopper separates from the vacuum sintering furnace.

7. The vacuum sintering furnace according to claim 1, characterized in that: The vacuum sintering furnace also includes a sintering box opening device and an opening assembly; sintering boxes are placed on the sintering box support; the opening assembly is located inside the heater and distributed on both sides of the sintering box; the sintering box opening device is located at the top of the vacuum furnace shell, and a guide shaft passes through the vacuum furnace shell and the heat insulation screen of the heating chamber and is connected to the opening assembly; the sintering box opening device can drive the guide shaft to move the opening assembly up and down.

Images