Waste-less or waste-free sintered neodymium iron boron processing equipment

Abstract

According to the waste-less or waste-free sintered neodymium-iron-boron machining equipment, in the temperature environment needed by the heat insulation interlayer, the piston sets drive the pressing heads correspondingly, and the surface of a workpiece to be machined is extruded inwards from each side wall of the heat insulation interlayer. Therefore, in the sintering machining process of the workpiece, the pressure applying parameters of different positions of the workpiece are dynamically adjusted according to the target shape, the neodymium iron boron mark and the sintering time of the workpiece, the deformation amount of the neodymium iron boron under the pressure head in the sintering process is limited, and waste generated by sintering machining is reduced or waste-free sintering machining is achieved. According to the sintered neodymium iron boron processing equipment with less / no waste, intelligent control of a system can be realized, the sintering process of a neodymium iron boron permanent magnet material is controlled in real time, and the stability and controllability of deformation in the sintering process of a neodymium iron boron blank are ensured.

Description

TECHNICAL FIELD

[0001] The application relates to the rare earth neodymium iron boron processing technology field, in particular to a little waste or no waste sintered neodymium iron boron processing equipment. BACKGROUND

[0002] Neodymium iron boron, as a representative of rare earth permanent magnet materials, is the largest production, the most widely used and the fastest developing rare earth product in the global rare earth material industry, is a national key emerging strategic material, accounts for 91% of the global rare earth consumption value, China is the largest country in the production of neodymium iron boron rare earth permanent magnet materials in the world, and the production reached 216,500 tons in 2021. A large amount of neodymium iron boron waste is generated during the production process of neodymium iron boron, and the waste quality accounts for about 20%-50% of the mass of the sintered neodymium iron boron blank, resulting in huge economic waste. The main link of waste generation is concentrated in the processing process. The processing process needs to machine or grind the permanent magnet material according to the target shape of the workpiece, and the mud-like grinding waste and the corner material block generated by wire cutting account for about 80% of the total amount of waste. Therefore, how to reduce the generation of waste in the sintered neodymium iron boron processing process is a problem that needs to be solved in the processing of neodymium iron boron materials at the present stage.

[0003] The existing powder metallurgy sintering pusher furnace (application number CN202410429383.8) proposes to introduce ultrasonic waves together with sintering pressure and sintering temperature on the basis of traditional vacuum hot pressing, realize the common coupling of ultrasonic waves, pressure and temperature to complete sintering, so as to realize the densification, grain refinement, escape of pores and uniformization of grain distribution of the sintered refractory material. However, no matter by what way, the existing technology is difficult to control the size precision of the sintered material, and it is extremely difficult to realize the processing of little waste or even no waste. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a little waste or no waste sintered neodymium iron boron processing equipment. The application controls the material forming in the sintering process by respectively applying different pressures to each region of the workpiece in the processing during the sintering process, improves the processing precision, improves the material utilization rate, can solve the raw material waste in the production process of sintered rare earth permanent magnets to a certain extent, and realizes the little / no waste processing of permanent magnet materials in the sintering process. The application specifically adopts the following technical solutions.

[0005] First, in order to achieve the above-mentioned purpose, a sintered Nd-Fe-B processing equipment with little or no waste is provided, which comprises: a heat-insulating interlayer for enclosing the workpiece to be processed and maintaining the temperature environment required for processing; a piston group arranged on each side wall of the heat-insulating interlayer, respectively, and fixed outside the heat-insulating interlayer, each piston in the piston group is respectively connected with a transmission pressure head, and the distal end of each transmission pressure head is further fixedly connected with a high-temperature pressure head; the high-temperature pressure head extends from the outer wall of the heat-insulating interlayer to the surface of the workpiece to be processed, and during the sintering process of the workpiece, the pressure parameters for different positions of the workpiece are dynamically adjusted according to the target shape, the Nd-Fe-B grade and the sintering time of the workpiece, the deformation amount of the Nd-Fe-B during sintering under the pressure head is limited, and the waste generated during sintering is reduced or sintering without waste is realized.

[0006] Optionally, the sintered Nd-Fe-B processing equipment with little or no waste as claimed in any one of the above, wherein the transmission pressure head is a stainless steel pressure head connected with the piston and arranged outside the heat-insulating interlayer.

[0007] Optionally, the sintered Nd-Fe-B processing equipment with little or no waste as claimed in any one of the above, wherein the high-temperature pressure head is any one or a combination of a graphite pressure head, a quartz pressure head and a high-temperature metal alloy pressure head connected at the end of the transmission pressure head and located inside the sintering furnace body and pressed against the surface of the workpiece blank to be sintered.

[0008] Optionally, the sintered Nd-Fe-B processing equipment with little or no waste as claimed in any one of the above, wherein the heat-insulating interlayer is wrapped outside the sintering furnace body, and the processing temperature of the sintering furnace is set between 600℃ and 1070℃.

[0009] Optionally, the sintered Nd-Fe-B processing equipment with little or no waste as claimed in any one of the above, wherein during the sintering process: during the process of increasing the processing temperature in the sintering furnace from room temperature to 600℃, the piston group applies pressure to the pressure head in each direction of the workpiece to be processed, so that the high-temperature pressure head moves a first compression distance towards the center of the workpiece; during the process of increasing the processing temperature in the sintering furnace from 600℃ to the target temperature, the piston group applies pressure to the pressure head in each direction of the workpiece to be processed, so that the high-temperature pressure head moves a second compression distance towards the center of the workpiece; and the first compression distance is less than the second compression distance.

[0010] Optionally, the sintered Nd-Fe-B processing equipment with little or no waste as claimed in any one of the above, wherein during the process of maintaining the processing temperature in the sintering furnace at the final target temperature for stable sintering, the piston group continues to apply pressure to the pressure head in each direction of the workpiece to be processed, so that the high-temperature pressure head moves a third compression distance towards the center of the workpiece; and the third compression distance is not greater than the first compression distance.

[0011] Optionally, the little or no waste sintered Nd-Fe-B processing equipment as claimed in any one of the above, wherein in each sintering stage, the compression distance of each ram located at the upper part of the workpiece blank is greater than the compression distance of each ram located at the lower part of the workpiece blank in the same stage.

[0012] Optionally, the little or no waste sintered Nd-Fe-B processing equipment as claimed in any one of the above, wherein in each sintering stage, the compression distance of each ram located at the lower part of the workpiece blank is greater than the compression distance of each ram located at the middle part of the workpiece blank in the same stage.

[0013] Optionally, the little or no waste sintered Nd-Fe-B processing equipment as claimed in any one of the above, further comprising: a monitoring module for collecting real-time positions of each high-temperature ram of the piston group; a driving unit for outputting driving signals to the piston group to drive each high-temperature ram to move to a corresponding position; and a controller connected to the monitoring module and the driving unit, for dynamically adjusting driving parameters of each high-temperature ram of the piston group by the driving unit according to a target shape of the workpiece, a grade of the Nd-Fe-B, a sintering time, and the real-time positions of each high-temperature ram of the piston group, so that each high-temperature ram is driven to the corresponding position, thereby ensuring deformation of the Nd-Fe-B workpiece at the position of each high-temperature ram during sintering of the Nd-Fe-B.

[0014] Optionally, the little or no waste sintered Nd-Fe-B processing equipment as claimed in any one of the above, wherein the monitoring module comprises a laser interferometer and an accelerometer for monitoring real-time positions and speeds of each high-temperature ram connected to the workpiece in each direction, so as to obtain a state vector of a kinetic model of the workpiece; the driving unit is a piezoelectric ceramic driver for adjusting real-time positions of each high-temperature ram of the piston group according to a control input of the controller; and the controller calculates a control signal output to the driving unit according to a state vector of a kinetic model of the workpiece, and a time-varying system matrix corresponding to a current target shape of the workpiece, a grade of the Nd-Fe-B, and a sintering time, according to an adaptive control strategy; wherein the time-varying system matrix contains coupling components between each high-temperature ram.

[0015] Advantages The sintered Nd-Fe-B processing equipment with less or no waste provided by the present application drives the pressure head by the piston group respectively from each side wall of the heat insulation interlayer to the surface of the workpiece to be processed in the temperature environment required by the heat insulation interlayer. Thus, during the sintering process of the workpiece, the pressure parameters of different positions of the workpiece are dynamically adjusted according to the target shape, the Nd-Fe-B grade and the sintering time of the workpiece, the deformation amount of the Nd-Fe-B during sintering under the pressure head is limited, and the waste generated by sintering is reduced or the sintering process without waste is realized. The sintered Nd-Fe-B processing equipment with less or no waste provided by the present application can realize intelligent control of the system, and the real-time control of the sintering process of the Nd-Fe-B permanent magnet material, to ensure the stability and controllability of the deformation of the Nd-Fe-B blank during the sintering process.

[0016] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, and together with the embodiments of the present application, serve to explain the present application, and do not constitute a limitation on the present application. In the drawings: Figure 1 is a schematic diagram of the sintered Nd-Fe-B processing equipment with less or no waste of the present application; Figure 2 is a principle block diagram of the device of the present application; In the figure, 1 represents the piston group; 2 represents the transmission pressure head; 3 represents the high-temperature pressure head; and 4 represents the heat insulation interlayer. DETAILED DESCRIPTION

[0018] In order to make the purpose and technical solutions of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as that generally understood by those skilled in the art in the field of the present application. It should also be understood that terms such as those defined in a general dictionary should be understood as having meanings consistent with those in the context of the prior art, and should not be interpreted with idealized or overly formal meanings unless otherwise defined.

[0020] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0021] In this application, "inner" and "outer" refer to the direction pointing towards the workpiece processing position inside the furnace relative to the sintering furnace itself, and conversely, the direction pointing from the workpiece inside the furnace towards the insulation interlayer, and not to a specific limitation on the device mechanism of this application.

[0022] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0023] The terms "upper" and "lower" as used in this application refer to the direction from the bottom of the sintering furnace towards the workpiece inside when the user is facing the furnace, and vice versa, rather than a specific limitation on the device mechanism of this application.

[0024] Figure 1 According to this application, a sintered NdFeB processing equipment with low or no waste is provided, comprising: The heat insulation layer 4, which is wrapped around the sintering furnace body, is used to seal the workpiece to be processed and maintain the temperature environment required for its processing. Piston assembly 1 is respectively disposed on each side wall of the heat insulation jacket 4 and fixed to the outside of the heat insulation jacket 4. Each piston in the piston assembly 1 is connected to a transmission head 2. The far end of each transmission head 2 is also fixedly connected to a high-temperature head 3 that extends into the sintering furnace body. The high-temperature pressure head 3 extends from the outer wall of the heat insulation layer 4 to the surface of the workpiece to be processed. During the sintering process of the workpiece, the pressure parameters applied by each pressure head to different positions of the workpiece are dynamically adjusted according to the target shape of the workpiece, the NdFeB grade, and the sintering time. This limits the amount of deformation of the NdFeB under the pressure head during the sintering process, reduces the waste generated during sintering, or achieves waste-free sintering.

[0025] Considering that the temperature in the sintering furnace can reach thousands of degrees Celsius, the heat-insulating sandwich structure of this application can specifically include multiple layers such as a heat-insulating layer, a heat-conducting layer, and a heat-dissipating layer. This ensures the protection of the structure below the mounting plate by the mounting plate, thereby preventing the heat from the sintering furnace body from affecting the external structure of the heat-insulating sandwich structure during operation. Furthermore, since the sintering temperature can reach over 1000 degrees Celsius, the transmission pressure head 2 connected to the outside of the sintering furnace is generally made of stainless steel to provide sufficient structural strength. Simultaneously, the high-temperature pressure head 3, extending through the heat-insulating sandwich structure into the sintering furnace body, is made of any one or a combination of graphite, quartz, and high-temperature resistant metal alloy, connected to the end of the transmission pressure head 2 and pressing against the surface of the workpiece blank to be sintered. Thus, this application can utilize the high-temperature properties of graphite to ensure that the pressure structure will not melt at high temperatures and lose its extrusion power; at the same time, the stainless steel transmission pressure head reduces equipment manufacturing costs. Placing the connection between the graphite pressure head and the stainless steel pressure head outside the sintering furnace effectively prevents the stainless steel from melting at high temperatures.

[0026] In the aforementioned apparatus, the smaller the size and the more densely distributed the pressure heads connected to piston assembly 1, the better the processing effect. In this application, each pressure head must completely enclose the entire blank to avoid bulging.

[0027] Taking a square permanent magnet with grade N45 and dimensions of 45×45×45mm as an example: During the processing, a square permanent magnet blank with dimensions of 50×50×50mm is usually used as the workpiece to be processed. It is placed in a sintering furnace, and the furnace body and heat insulation layer are sealed. Then, the temperature inside the sintering furnace is raised from room temperature to 600℃. During this process, the piston assembly 1 is driven to apply pressure to the pressure head in each direction of the workpiece to be processed, so that the high-temperature pressure head 3 moves towards the center of the workpiece by a first compression distance. For a blank of 50×50×50mm, the first compression distance can generally be set as follows: the upper end of the blank shrinks by 0.6 mm, the middle shrinks by 0.2 mm, and the lower part shrinks by 0.8 mm. Then, the processing temperature in the sintering furnace is further increased from 600℃ to the target temperature of 1070℃. During this process, the piston assembly 1 is further driven to apply pressure to the pressure heads in all directions of the workpiece to be processed, so that the high-temperature pressure head 3 moves a larger second compression distance toward the center of the workpiece. For a 50×50×50mm blank, the second compression distance can generally be set as follows: the upper end of the blank shrinks by 4 mm, the middle part shrinks by 3.2 mm, and the lower part shrinks by 3.7 mm. Finally, the processing temperature inside the sintering furnace is maintained at the final target temperature for stable sintering. During this process, the synchronously driven piston assembly 1 continues to apply pressure to the pressure heads in all directions of the workpiece, causing the high-temperature pressure head 3 to move a small third compression distance toward the center of the workpiece. This third compression distance is generally set to be no greater than the first compression distance. For a 50×50×50mm blank, this second compression distance can generally be specifically set as follows: causing the permanent magnet blank to shrink by 0.5 mm at the top, 0.2 mm in the middle, and 0.3 mm at the bottom during the heat preservation process.

[0028] The reason why the compression distance of each pressure head located on the upper part of the workpiece blank is set to be greater than that of each pressure head located on the lower part of the workpiece blank in the same stage during the sintering process, and the compression distance of each pressure head located on the lower part of the workpiece blank is set to be greater than that of each pressure head located on the middle part of the workpiece blank in the same stage, is that different parts of the workpiece are heated unevenly during sintering. Furthermore, the area located on the lower part of the workpiece is more affected by gravity, and therefore will shrink more due to gravity, while the upper and middle parts of the workpiece will shrink less. This application utilizes the pressure head at different positions to compensate for the different shrinkage rates of the workpiece itself, thereby controlling the sintering shrinkage direction through the pressure head to achieve processing with less / zero waste.

[0029] After sintering according to the above process, the NdFeB is tempered. During the tempering process, the NdFeB blank has completed the densification process, and the material size remains unchanged.

[0030] To accurately control the pressure applied to the workpiece blank at each stage of the sintering process, achieve intelligent system control, and ensure real-time control of the NdFeB permanent magnet material sintering process, thereby guaranteeing the stability and controllability of the deformation of the NdFeB blank during sintering, this application may further refer to... Figure 2 The method involves arranging monitoring modules on each piston of the piston group to collect and monitor the real-time position of each high-temperature pressure head 3 in the piston group; and according to the real-time sintering temperature and sintering time of the sintering furnace, the controller sends the driving parameters for each high-temperature pressure head 3 to the drive unit in the following manner, so that the drive unit can accurately drive each high-temperature pressure head 3 to move to the corresponding position by the driving signal output by each piston of the piston group, and adjust the pressure applied to different positions of the workpiece blank in real time.

[0031] Figure 2 In this process, the monitoring module can specifically employ a laser interferometer and an accelerometer mounted on the pressure head. The laser interferometer monitors the real-time position of the high-temperature pressure head 3 connected to the workpiece in each direction, and the accelerometer detects the real-time velocity of the high-temperature pressure head 3 connected to the workpiece in each direction, thereby obtaining the state vector of the workpiece dynamic model. ; The drive unit may be a piezoelectric ceramic actuator, which operates based on the control input provided by the controller. The real-time position of each high-temperature pressure head 3 in the corresponding drive piston assembly is adjusted; The controller, following an adaptive control strategy, calculates the control signal to be output to the drive unit in real time based on the state vector of the workpiece dynamics model and the time-varying system matrix corresponding to the current workpiece target shape, NdFeB grade, and sintering time, as follows: First, based on the target shape and NdFeB grade of the workpiece, its dynamic model is established and expressed in the form of a linear time-varying state equation: .in, , For the time-varying system matrix containing coupling terms between pressure heads, External disturbance; Model reference adaptive control (MRAC) is employed to design a reference model. An adaptive law is designed based on Lyapunov stability theory to address the error. With convergence as the objective, the corresponding control input parameters are obtained iteratively. The control input parameters are used to drive each pressure head to apply pressure to the workpiece from all directions, thus driving the workpiece to follow a predetermined desired trajectory during the sintering process. By shrinking the material to a compact size, the workpiece structure that is closest to the design target can be obtained directly. Then, the excess parts on the surface can be simply shaved and ground according to the shape requirements of the workpiece to obtain the target workpiece with minimal waste.

[0032] In the above calculation process: The control input is adjusted in real time using an adaptive law. This makes the actual output Tracking reference model output .

[0033] Adaptive law All designs are based on Lyapunov stability theory to ensure error accuracy. Convergence, of which, It is a positive definite gain matrix, which guarantees parameter convergence.

[0034] The coupling compensation mechanism identifies the inter-axis coupling coefficient (such as the interference coefficient of other actuators on this actuator) online. Introducing decoupling terms into the control law Dynamically cancels out cross-interference.

[0035] In addition, the model in this application adds two modules: 1. Real-time optimization, and 2. Coupled identification, which are used for: Through real-time optimization, hardware acceleration modules (such as matrix multiplication IP cores) are used in the FPGA to compress the calculation time of the adaptive law to less than 50μs. Furthermore, sensor data filtering techniques are utilized, specifically the use of a Kalman filter to suppress noise in the laser interferometer, thereby improving the signal-to-noise ratio of the detected signal during the control process by 30dB. The coupling matrix is ​​initialized offline using coupling identification and impulse response experiments. Online, using the least squares method with a learning rate of 0.01~0.1. Iterative updates: .

[0036] Taking the aforementioned square permanent magnet with grade N45 and dimensions of 45×45×45mm as an example: Through the above calculation process, this application enables the central controller to issue real-time commands to the actuator based on the above data and the temperature change curve of the NdFeB sintering process, thereby controlling the piston movement in the cylinder of the actuator and driving the graphite pressure head on the piston to control the sintering process of the NdFeB material. When the sintering temperature rises from room temperature to 600℃, the controller issues commands to move the piston in the solenoid valve drive cylinder at the top of the NdFeB billet 0.6 mm in the direction of pressure, the piston in the solenoid valve drive cylinder at the middle of the NdFeB billet 0.2 mm in the direction of pressure, and the piston in the solenoid valve drive cylinder at the bottom of the NdFeB billet 0.8 mm in the direction of pressure. As the furnace temperature rises from 600℃ to 1070℃, the controller issues commands to move the piston in the solenoid valve drive cylinder at the top of the NdFeB billet 4 mm in the direction of pressure, the piston in the solenoid valve drive cylinder at the middle of the NdFeB billet 3.2 mm in the direction of pressure, and the piston in the solenoid valve drive cylinder at the bottom of the NdFeB billet 3.7 mm in the direction of pressure. mm; As the furnace temperature remains constant, during the heat preservation stage of the NdFeB material, the controller issues commands to move the piston in the cylinder driven by the electromagnetic reversing valve at the top of the NdFeB blank 0.5 mm in the direction of pressure, the piston in the cylinder driven by the electromagnetic reversing valve at the middle of the NdFeB blank 0.2 mm in the direction of pressure, and the piston in the cylinder driven by the electromagnetic reversing valve at the bottom of the NdFeB blank 0.3 mm in the direction of pressure. The final sintered NdFeB blank has dimensions of 44.9 × 46.4 × 45.2 mm, only slightly different from the expected size of a square permanent magnet of 45 × 45 × 45 mm, effectively reducing waste in industrial production.

[0037] In the aforementioned system, the control unit can utilize a data storage device to store shrinkage data of various parts of the NdFeB blanks of all grades and shapes during the sintering process at different sintering times, temperatures, and locations within the sintering furnace. This provides fundamental parameters for multivariate system modeling. The central processing unit (CPU) mounted on the control unit calculates the shrinkage data of different parts of the blank based on fundamental data such as the NdFeB grade, shape, placement, sintering temperature, and time during the sintering process. This data is then transmitted via a signal transmission system to the flux-reversing valve in the actuator, controlling its operation. The data transmission system transmits the electrical signals processed by the CPU to the actuator via a data bus.

[0038] The actuator may specifically include a pneumatic directional valve, a cylinder, a piston, and a pressure head. The pneumatic solenoid valve receives electrical signals processed by a central processing unit transmitted through a data transmission system, controlling the air pressure at both ends of the piston within the cylinder. The piston is located inside the cylinder, and the cylinder, guided by a pneumatic regulating valve that adjusts the air pressure at both ends of the piston, directs the piston to perform linear reciprocating motion within the cylinder. The piston is connected to one end of the stainless steel pressure head via a piston push rod.

[0039] Specifically, the actuator can be flexibly adopted according to the driving requirements, such as pneumatic actuator, hydraulic actuator, crank-slider actuator, gear and rack actuator, or stepless curve displacement actuator.

[0040] The above are merely embodiments of this application, and their descriptions are quite specific and detailed, but they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A sintered NdFeB processing equipment with low or no waste, characterized in that, include: The heat insulation layer (4) is used to seal the workpiece to be processed and maintain the temperature environment required for its processing; Piston assembly (1), which is respectively set on each side wall of the heat insulation jacket (4) and fixed on the outside of the heat insulation jacket (4), each piston in the piston assembly (1) is respectively connected to a transmission head (2), and a high temperature head (3) is also fixedly connected to the far end of each transmission head (2). The high-temperature pressure head (3) extends from the outer wall of the heat insulation layer (4) to the surface of the workpiece to be processed. During the sintering process of the workpiece, the pressure parameters applied to different positions of the workpiece are dynamically adjusted according to the target shape, NdFeB grade and sintering time of the workpiece, limiting the amount of deformation of NdFeB under the pressure head during the sintering process, reducing the waste generated by the sintering process or achieving waste-free sintering process.

2. The sintered NdFeB processing equipment with low or no waste as described in claim 1, characterized in that, The transmission head (2) is a stainless steel head that connects to the piston and is located on the outside of the heat insulation jacket (4).

3. The sintered NdFeB processing equipment with low or no waste as described in claim 1, characterized in that, The high-temperature pressure head (3) is any one or a combination of graphite pressure head, quartz pressure head, and high-temperature resistant metal alloy pressure head connected to the end of the transmission pressure head (2), located inside the sintering furnace, and pressed against the surface of the workpiece blank to be sintered.

4. The sintered NdFeB processing equipment with low or no waste as described in claim 1, characterized in that, The heat insulation interlayer (4) is wrapped around the sintering furnace body, and the processing temperature of the sintering furnace is set between 600°C and 1070°C.

5. The sintered NdFeB processing equipment with low or no waste as described in claim 4, characterized in that, During the sintering process: During the process of the processing temperature in the sintering furnace rising from room temperature to 600°C, the piston assembly (1) applies pressure to the pressure head in each direction of the workpiece to be processed, causing the high-temperature pressure head (3) to move a first compression distance toward the center of the workpiece. During the process of the processing temperature in the sintering furnace rising from 600℃ to the target temperature, the piston assembly (1) applies pressure to the pressure head in each direction of the workpiece to be processed, causing the high temperature pressure head (3) to move a second compression distance toward the center of the workpiece. The first compression distance is less than the second compression distance.

6. The sintered NdFeB processing equipment with low or no waste as described in claim 5, characterized in that, During the sintering process, the piston assembly (1) continues to apply pressure to the pressure head in each direction of the workpiece to be processed, so that the high temperature pressure head (3) moves towards the center of the workpiece by a third compression distance. The third compression distance is no greater than the first compression distance.

7. The sintered NdFeB processing equipment with low or no waste as described in claim 6, characterized in that, In each sintering stage, the compression distance of each pressure head located on the upper part of the workpiece blank is greater than the compression distance of each pressure head located on the lower part of the workpiece blank in the same stage.

8. The sintered NdFeB processing equipment with low or no waste as described in claim 6, characterized in that, In each sintering stage, the compression distance of each pressure head located at the bottom of the workpiece blank is greater than the compression distance of each pressure head located in the middle of the workpiece blank in the same stage.

9. The sintered NdFeB processing equipment with low or no waste as described in claims 1-6, characterized in that, Also includes: The monitoring module is used to collect the real-time position of each high-temperature pressure head (3) of the monitoring piston assembly; The drive unit is used to output drive signals to the piston assembly to drive each high-temperature pressure head (3) to move to the corresponding position. The controller, which connects the monitoring module and the drive unit, is used to dynamically adjust the drive parameters of the drive unit on each high-temperature pressure head (3) of the piston group according to the target shape of the workpiece, the NdFeB grade, the sintering time and the real-time position of each high-temperature pressure head (3) of the piston group, so that each high-temperature pressure head (3) is driven to the corresponding position, thereby ensuring the deformation of the NdFeB workpiece at each pressure head position during the NdFeB sintering process.

10. The sintered NdFeB processing equipment with low or no waste as described in claims 1-9, characterized in that, The monitoring module includes a laser interferometer and an accelerometer, which are used to monitor the real-time position and velocity of the high-temperature pressure head (3) connected to the workpiece in each direction, so as to obtain the state vector of the workpiece dynamic model. The driving unit is a piezoelectric ceramic actuator, which adjusts the real-time position of each high-temperature pressure head (3) of the corresponding driving piston group according to the control input of the controller; The controller, in accordance with an adaptive control strategy, calculates the control signal to be output to the drive unit in real time based on the state vector of the workpiece dynamics model and the time-varying system matrix corresponding to the current workpiece target shape, NdFeB grade, and sintering time. The time-varying system matrix contains coupling components between each high-temperature pressure head (3).

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