Vacuum sintering furnace workpiece supporting device and placement optimization method

Abstract

The invention provides a vacuum sintering furnace workpiece supporting device and a placement optimization method, and relates to the technical field of vacuum sintering furnace workpiece placement and heat transfer. A workpiece supporting device of a vacuum sintering furnace comprises a side supporting plate, a lower supporting plate, a clamping device, a temperature measuring device and a horizontal measuring device, the clamping device is designed to be an adjustable device and can adapt to tubular workpieces of different sizes, the temperature measuring device is moved, the temperature in the sintering process is monitored in real time, and it is ensured that the temperature in the sintering process is uniform; the infrared thermometer is connected with the air cylinder outside the furnace through the adjustable connecting rod, so that high-temperature returning can be realized, and the infrared thermometer is prevented from being damaged due to high temperature; according to the workpiece placement optimization method for the vacuum sintering furnace, an optimal workpiece placement mode is obtained by combining heat transfer theory simulation and a genetic algorithm, the influence of an internal supporting plate on workpiece temperature uniformity is reduced, and sintering efficiency is improved, energy consumption is reduced, and workpiece quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of workpiece placement and heat transfer in a vacuum sintering furnace, and in particular to a workpiece support device and a placement optimization method for a vacuum sintering furnace. Background Art

[0002] The vacuum sintering furnace is one of the indispensable equipment in the powder metallurgy industry and is a high-energy consumption equipment in industrial furnaces. Due to the high temperature inside the vacuum sintering furnace, the temperature inside the furnace cannot be accurately measured by contact measurement methods, and the accuracy of non-contact measurement methods is poor. The uniformity of the temperature inside the vacuum furnace and the uniformity of the workpiece temperature are the main basis for judging the performance of the vacuum sintering furnace. Therefore, the soft measurement of the workpiece temperature is realized by software simulation calculation, and a database of the influence factors of the workpiece placement on the workpiece temperature uniformity is established, and the workpiece placement is optimized using the database. As an important material processing equipment, the vacuum sintering furnace is widely used in the sintering process of ceramics, metals, composite materials and other fields. During the vacuum sintering process, the placement of the workpiece has a significant impact on the sintering efficiency, energy consumption and workpiece quality. However, the existing workpiece placement methods mostly rely on manual experience and lack scientific and systematic guidance, resulting in low sintering efficiency, high energy consumption, and unstable workpiece quality.

[0003] Chinese patent "CN114492079A A method for optimizing silicon carbide vacuum sintering furnace based on computational heat transfer simulation" discloses a method for optimizing silicon carbide vacuum sintering furnace based on computational heat transfer simulation, including the following steps: establishing a heat radiation and heat conduction model of the vacuum sintering furnace during the heating process according to the parameters of the vacuum sintering furnace body; performing computational heat transfer simulation to obtain the temperature rise curve of the vacuum sintering furnace during the entire heating process; optimizing the original furnace type by calculating and comparing the temperature rise curves of the workpieces under different heating rates, different graphite heating tube diameters, and different graphite heating tube and effective heating zone spacings, the temperature difference between the vertex workpiece and the center workpiece, and the temperature difference between the surface and the core of the same workpiece. The present invention provides a reference for the performance optimization of the vacuum sintering furnace by studying the effects of different heating rates, different graphite heating tube diameters, and different graphite heating tube and effective heating zone spacings on the heating efficiency and furnace temperature uniformity of the vacuum sintering furnace, meets the process production requirements of the silicon carbide vacuum sintering furnace, and improves the heating efficiency and furnace temperature uniformity of the heating system.

[0004] The Chinese patent "CN114492079A A method for optimizing a silicon carbide vacuum sintering furnace based on computational heat transfer simulation" describes the study of the effects of different heating rates, different graphite heating tube diameters, and different distances between the graphite heating tube and the effective heating zone on the heating efficiency and furnace temperature uniformity of the vacuum sintering furnace, providing a reference for the performance optimization of the vacuum sintering furnace, meeting the process production requirements of the silicon carbide vacuum sintering furnace, and improving the heating efficiency and furnace temperature uniformity of the heating system. It only studies the effects of the process and structure on the temperature uniformity in the furnace, and does not propose the effects of the placement of the workpiece on the temperature uniformity in the furnace and the workpiece.

[0005] The Chinese patent "CN113912053B A method for anti-oxidation loading of isostatic graphite roasting process" uses experimental means to study its loading method, so as to improve the quality of warm sintering, but this method is much more expensive than simulation methods, so it has limitations. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a workpiece support device for a vacuum sintering furnace and a placement optimization method in view of the above-mentioned deficiencies in the prior art.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] In one aspect, the present invention provides a workpiece support device for a vacuum sintering furnace, comprising a side support plate, a lower support plate, a clamping device, a temperature measuring device and a level measuring device;

[0009] The lower support plate is provided with a plurality of slide grooves in parallel, the clamping device is slidably connected in the slide grooves, and a side support plate is provided on the lower support plate through a lower clamping adjustment bolt. The side support plate is perpendicular to the clamping device along the moving direction of the slide groove and is used for limiting the movement of the clamping device;

[0010] The clamping device comprises two clamping arms arranged opposite to each other, used for clamping the tubular workpiece, the lower clamping bolt penetrates from the bottom end of the lower support plate and is screwed on the clamping arm, the two clamping arms are arranged along the moving direction of the slide slot, and the distance between the two clamping arms is adjusted by adjusting the position of the lower clamping bolt, so as to clamp tubular workpieces of different diameters;

[0011] Further, the clamping arm comprises a clamping bolt, an upper clamping head and a lower clamping head, the clamping bolt is made of graphite material, the lower clamping head is screwed on the lower support plate, the upper clamping head and the lower clamping head are screwed with the clamping bolt, and the positions of the upper and lower clamping heads on the clamping bolt are adjusted to clamp tubular workpieces of different diameters;

[0012] The temperature measuring device includes a temperature measuring ring, an infrared thermometer and a cylinder. The side support plate, the lower support plate and the clamping device are provided with a temperature measuring ring mounting hole. The temperature measuring ring is installed on the temperature measuring ring mounting hole. The infrared thermometer is installed in the infrared thermometer mounting hole reserved on the side of the side support plate and is connected to the cylinder outside the vacuum sintering furnace through an adjustable connecting rod.

[0013] Furthermore, the temperature measuring ring is used to obtain the temperature uniformity of the sintering process at different positions, and the final sintering temperature is determined by using the deformation law of the temperature measuring ring; the infrared thermometer moves vertically along the side support plate to measure the temperature of the tube-shaped workpiece, and as the temperature rises, the infrared thermometer can be retracted by the moving cylinder to ensure the stable use of the infrared thermometer;

[0014] The level measuring device includes an infrared level and a level calibration bolt. The infrared level is installed on the lower support plate just below the infrared thermometer installation hole. The level calibration bolt is evenly screwed under the lower support plate along the horizontal direction of the side support plate.

[0015] Furthermore, the horizontal measuring device is used to measure the horizontality of the workpiece and the supporting device during the workpiece placement process, and to adjust the horizontality of the workpiece and the supporting device by adjusting the length of the horizontal calibration bolt to ensure that the workpiece and the supporting device are in a horizontal state.

[0016] On the other hand, the present invention provides a method for optimizing the placement of workpieces in a vacuum sintering furnace, which specifically comprises the following steps:

[0017] Step 1: Establish the thermal radiation and heat conduction model of vacuum sintering process according to the vacuum furnace parameters;

[0018] Step 2: Set the population size, crossover rate, and mutation rate of the genetic algorithm, and randomly generate an initial population representing possible solutions. Each individual in the population represents a way to place the workpiece.

[0019] Further, the parameters that affect the placement of the workpieces in the vacuum sintering furnace are the compactness of the workpiece placement, the thickness of the upper support plate, the thickness of the side support plate in the workpiece support device, and the thickness of the lower support plate;

[0020] Step 3: Use user-defined functions to control the process temperature and power, and according to the sintering temperature rise process curve, obtain the temperature distribution in the vacuum sintering furnace and the temperature of each point on the workpiece, simulate the entire heating process, and establish a soft measurement method for the workpiece temperature through simulation to obtain the temperature uniformity of different positions of workpieces with different placement methods. Calculate the heating efficiency of each workpiece placement method and the temperature uniformity in the furnace and the workpiece as a fitness evaluation;

[0021] Step 4: According to the fitness evaluation results, select the better individuals to enter the next generation;

[0022] Step 5: Perform mutation operations on individuals to generate diversity and find better solutions;

[0023] Step 6: Perform simulated annealing on each individual and conduct local search to find a better solution;

[0024] Step 7: Determine whether the conditions for stopping the generation selection are met according to the preset stopping conditions;

[0025] Step 8: Return the best individual as the optimal solution for workpiece placement, and perform simulation and actual verification.

[0026] The beneficial effects of adopting the above technical solution are:

[0027] The present invention provides a workpiece support device for a vacuum sintering furnace, wherein the clamping device is designed as an adjustable device, which can adapt to workpieces of different sizes, and the damaged part can be quickly replaced. At the same time, the locking bolt is made of graphite material with good stability and corrosion resistance at high temperatures; and a movable temperature measuring device is provided to monitor the temperature of the sintering process in real time to ensure that the temperature of the sintering process is uniform. The temperature measuring device is connected to the cylinder outside the furnace through an adjustable connecting rod, which can realize high-temperature return and prevent the temperature measuring device from being damaged by high temperature;

[0028] The present invention provides a method for optimizing the placement of workpieces in a vacuum sintering furnace. The method utilizes a combination of heat transfer simulation and genetic algorithm to obtain the optimal workpiece placement method, thereby reducing the influence of an internal support plate on the temperature uniformity of the workpiece, thereby achieving improved sintering efficiency, reduced energy consumption, and improved workpiece quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A front view of a workpiece support device for a vacuum sintering furnace provided by an embodiment of the present invention;

[0030] Figure 2 A top view of a workpiece support device for a vacuum sintering furnace provided in an embodiment of the present invention;

[0031] Figure 3 A disassembly diagram of a clamping device provided in an embodiment of the present invention;

[0032] Figure 4 A schematic diagram of the installation position of the temperature measuring device provided in an embodiment of the present invention;

[0033] Figure 5 A schematic diagram of the cylinder arrangement of a vacuum sintering furnace provided in an embodiment of the present invention;

[0034] Figure 6 A schematic diagram of the installation position of the measuring device provided in an embodiment of the present invention;

[0035] Figure 7A schematic diagram of the position of the horizontal adjustment bolt provided in an embodiment of the present invention (I);

[0036] Figure 8 Schematic diagram of the position of the horizontal adjustment bolt provided by the embodiment of the present invention (II);

[0037] Fig. 9 A flow chart of a method for optimizing the placement of workpieces in a vacuum sintering furnace provided by an embodiment of the present invention;

[0038] Fig.10 A diagram showing the components of a vacuum sintering furnace provided in an embodiment of the present invention;

[0039] Fig.11 A schematic diagram of the arrangement and position of workpieces in a vacuum sintering furnace simulation process provided by an embodiment of the present invention;

[0040] Fig.12 A schematic diagram of the arrangement of temperature monitoring points in a vacuum sintering furnace simulation process provided by an embodiment of the present invention;

[0041] Fig.13 A schematic diagram of a temperature curve for setting a sintering process in a vacuum sintering furnace simulation process provided by an embodiment of the present invention;

[0042] Fig.14 A schematic diagram of a comparison curve between simulated temperature and actual test temperature provided in an embodiment of the present invention;

[0043] Fig.15 The influence of the lower support plate provided by the embodiment of the present invention on temperature uniformity;

[0044] Fig.16 The effect of the thickness of the side plate on the temperature uniformity provided by the embodiment of the present invention;

[0045] Fig.17 The effect of the thickness of the side plate provided in the embodiment of the present invention on the temperature difference of different workpieces;

[0046] Fig.18 The effect of the thickness of the side plate provided in the embodiment of the present invention on the temperature difference between the workpieces;

[0047] Fig.19 A comparison of the temperature difference between the workpieces before and after optimization provided by the embodiment of the present invention;

[0048] Fig. 20 A comparison curve diagram of the temperature difference of a workpiece before and after optimization provided by an embodiment of the present invention;

[0049] Fig.21 A comparison curve diagram of the temperature difference between the temperature measuring points of the workpiece before and after optimization provided by the embodiment of the present invention;

[0050] In the figure: 1. side support plate; 2. lower support plate; 3. slide groove; 4. tubular workpiece; 5. lower clamping bolt; 6. clamping arm; 7. clamping bolt; 8. upper clamping head; 9. lower clamping head; 10. vacuum sintering furnace; 11. cylinder; 12. temperature measuring ring mounting hole; 13. temperature measuring ring; 14. infrared thermometer mounting hole; 15. infrared thermometer; 16. adjustable connecting rod; 17. infrared level; 18. level adjustment bolt; 19. water-cooled shell; 20. insulation layer; 21. graphite heating body; 22. upper support plate. DETAILED DESCRIPTION

[0051] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0052] To meet the needs of high-temperature sintering, the workpiece is easily deformed in the furnace due to being under its own gravity for a long time. Especially during the heating process, without proper support, the workpiece may be damaged by thermal expansion and gravity. Existing support devices may require complex operation and long replacement time, which limits the improvement of production efficiency.

[0053] In this embodiment, a vacuum sintering furnace workpiece support device, such as Figure 1-2 As shown, it includes a side support plate 1, a lower support plate 2, a clamping device, a temperature measuring device and a level measuring device;

[0054] The lower support plate is provided with a plurality of slide grooves 3 in parallel, and the clamping device is slidably connected in the slide grooves 3. A side support plate 1 is provided on the lower support plate 2 through a lower clamping adjustment bolt 5. The side support plate 1 is perpendicular to the moving direction of the clamping device along the slide groove 3 and is used for limiting the movement of the clamping device.

[0055] The clamping device comprises two clamping arms 6 arranged opposite to each other. Figure 3 As shown, it is used to clamp the tubular workpiece, the lower clamping bolt is inserted from the bottom end of the lower support plate 2 and is screwed on the clamping arm 6, the two clamping arms 6 are arranged along the moving direction of the slide slot, and the distance between the two clamping arms is adjusted by adjusting the position of the lower clamping bolt 5, so as to clamp the tubular workpieces with different diameters;

[0056] The clamping arm 6 includes a clamping bolt 7, an upper clamping head 8 and a lower clamping head 9. The clamping bolt is made of graphite material. The lower clamping head 9 is screwed on the lower support plate 2. The upper clamping head 8 and the lower clamping head 9 are screwed with the clamping bolt 7. By adjusting the positions of the upper and lower clamping heads on the clamping bolt 7, tubular workpieces with different diameters can be clamped.

[0057] The clamping device can realize the variable clamping limit function. Its design comprehensively considers the ease of operation, stability in high temperature environment, adaptability to workpieces of different sizes and durability for long-term use, aiming to improve the efficiency of the sintering process and the sintering quality of the workpiece. The clamping device is designed with the convenience of maintenance in mind, and vulnerable parts such as locking bolts can be quickly replaced; the device adopts a modular design and can adapt to workpieces of different sizes. The locking bolts are made of graphite material, which can facilitate operators to quickly adjust according to the size of the workpiece. It has good stability and corrosion resistance at high temperatures, is suitable for the environment in the sintering furnace, and prevents high-temperature deformation; the slide groove of the lower support plate can lock the clamping device and can slide.

[0058] The temperature measuring device includes a temperature measuring ring, an infrared thermometer and a cylinder. The side support plate 1, the lower support plate 2 and the clamping device are provided with a temperature measuring ring mounting hole 12. The temperature measuring ring 13 is mounted on the temperature measuring ring mounting hole 12. The infrared thermometer 15 is mounted in the infrared thermometer mounting hole 14 reserved on the side of the side support plate 1. Figure 4 As shown, the vacuum sintering furnace 10 is connected to the cylinder 11 outside the vacuum sintering furnace 10 through an adjustable connecting rod 16. Figure 5 As shown;

[0059] The temperature measuring ring 13 is used to obtain the temperature uniformity of the sintering process at different positions, and to determine the final sintering temperature using the deformation law of the temperature measuring ring;

[0060] The infrared thermometer 15 moves vertically along the side support plate 1 to measure the temperature of the tubular workpiece 4. As the temperature rises, the infrared thermometer 15 can be retracted by the moving cylinder 11 to ensure the stable use of the infrared thermometer 11 and prevent it from being damaged. Figure 5-6 As shown;

[0061] The parallel slide rail is set to the horizontal direction. The workpiece can be adjusted in the horizontal direction before installation to reduce the temperature uniformity of the workpiece in the horizontal direction. The installation position of the temperature measuring ring is reserved on the side support plate, the lower support plate and the clamping device of the workpiece to obtain the temperature uniformity of the sintering process at different positions. The temperature measuring device is a movable temperature measuring device. The infrared thermometer is moved in the horizontal direction to measure the temperature of the workpiece. As the temperature rises, the thermometer can be retracted by the moving cylinder to ensure the stable use of the thermometer and not easy to be damaged.

[0062] The horizontal position of the thermometer can be adjusted by an external adjustable connecting rod, which is simple and easy to implement, allowing operators to quickly respond to temperature changes. Improved temperature uniformity can reduce sintering cycles, speed up production rhythm, and improve overall production efficiency. The design takes into account the simplicity of operation and modularity, and the device is easy to maintain and upgrade.

[0063] The level measuring device includes an infrared level 17 and a level calibration bolt 18. The infrared level 17 is installed on the lower support plate 2 just below the infrared thermometer installation hole 14. Figure 6 As shown, the horizontal calibration bolts 18 are evenly screwed under the lower support plate 2 along the horizontal direction of the side support plate 1, as shown in FIG. Figure 7-8 As shown;

[0064] The horizontal measuring device is used to measure the horizontality of the workpiece and the supporting device during the workpiece placement process, and to adjust the horizontality of the workpiece and the supporting device by adjusting the length of the horizontal calibration bolt to ensure that the workpiece and the supporting device are in a horizontal state.

[0065] In this embodiment, a vacuum sintering furnace workpiece placement optimization method is provided. Fig. 9 As shown, the specific steps include:

[0066] Step 1: Establish the thermal radiation and heat conduction model of the vacuum sintering process according to the vacuum furnace parameters, considering the heat transfer characteristics in the vacuum environment;

[0067] Silicon carbide vacuum sintering furnace based on computational heat transfer simulation, its components are as follows Fig.10 As shown, the thermal physical properties of the vacuum sintering furnace material are shown in Table 1. The components of the vacuum sintering furnace mainly include a water-cooled shell 19, a thermal insulation layer 20, a graphite heating body 21, and an internal tooling. The tooling includes a workpiece support device, an upper support plate 22, and a tubular workpiece 4. In this embodiment, five layers of workpiece support devices are arranged in the vacuum sintering furnace, and each layer of support devices is provided with two layers of tubular workpieces, and the number of tubular workpieces on each layer is 10. The upper and lower support plates are made of graphite material, and the tubular workpiece is made of silicon carbide material;

[0068] Table 1 Thermophysical parameters of materials

[0069]

[0070] In this embodiment, the simulation model is a heating section of a vacuum sintering furnace. The model of the vacuum sintering furnace is ZSD-13000W. The pressure in the vacuum sintering furnace is 101325Pa before the coke discharge is completed, and the vacuum degree is 50Pa after the coke discharge. Ignoring the influence of convection heat transfer, the energy equation formula is as follows:

[0071]

[0072] Where t is time, s; ρ is density, kg / m 3 ; h is specific enthalpy, kj / kg, which represents the enthalpy per unit mass of a substance and is used to describe the energy contained in a substance, h = ∫C p dT,C p is the specific heat capacity at constant pressure J / (kg·K); is the Hamiltonian operator; u is the velocity vector, m / s; λ is the thermal conductivity, W / (m·K); T is the temperature, K; S h is the internal heat source, W / m 3 ;

[0073] The discrete ordinate DO radiation model is used as the thermal radiation and heat conduction model of the vacuum sintering process. The calculation formula is as follows:

[0074]

[0075] Where I is the radiation intensity, W / m 2 ; r is the radiation azimuth normal vector; s is the radiation length vector; s ′ is the scattering direction; α is the material absorption coefficient; σ s is the heat dissipation coefficient; n is the refractive index; σ is the blackbody radiation constant; Ω ′ is the radiation solid angle;

[0076] Step 2: Set the population size, crossover rate, and mutation rate of the genetic algorithm, and randomly generate an initial population representing possible solutions. Each individual in the population represents a way to place the workpiece.

[0077] In this embodiment, the schematic diagram of the workpiece arrangement and workpiece position in the vacuum sintering furnace simulation process is as follows: Fig.11 As shown in the figure, the main parameters affecting the workpiece placement in the vacuum sintering furnace are the compactness of the workpiece placement, the thickness of the upper support plate, the thickness of the middle support plate of the workpiece support device, and the thickness of the lower support plate. By changing several parameters, the influence of different parameters on the workpiece and the temperature uniformity in the furnace is obtained;

[0078] In this embodiment, the main parameter changed in the workpiece placement method is the thickness of each plate. First, different lower support plate thicknesses are simulated to obtain calculation results and the optimal lower support plate thickness is obtained. The optimal lower support plate thickness is used as a standard to change the side support plate thickness and obtain calculation results to obtain the rightmost thickness of the optimal side support plate. The optimal lower support plate and the optimal side support plate are used to change the upper support plate thickness, and simulation analysis is performed to obtain the optimal upper support plate thickness. The simulation calculation scheme is shown in Table 2.

[0079] Table 2 Design scheme of simulation calculation parameters

[0080]

[0081] like Fig.12The figure shows the schematic diagram of the arrangement of temperature monitoring points in the vacuum sintering furnace during the simulation process. The main purpose of setting temperature monitoring points in the furnace is to better monitor the temperature distribution in the furnace. The temperature uniformity in the furnace is obtained by obtaining the temperature of the monitoring points, and compared with the data obtained during the test process to determine the accuracy of the simulation.

[0082] Step 3: ANSYS Fluent software is used to control the process temperature and power using a user-defined function (UDF). Based on the sintering temperature rise process curve, the temperature distribution in the vacuum sintering furnace and the temperature of each point on the workpiece are obtained to simulate the entire heating process. Through simulation, a soft measurement method for the workpiece temperature is established to obtain the temperature uniformity of workpieces at different positions in different placements. The heating efficiency of each workpiece placement and the temperature uniformity in the furnace and on the workpiece are calculated as a fitness evaluation.

[0083] like Fig.13 The figure shows the temperature curve of the sintering process setting in the vacuum sintering furnace simulation process. The process curve can be set using UDF according to different sintering processes and the conditions of the sintered workpieces to make it consistent with the actual heating process, and to establish the determination standard of the temperature uniformity of the workpieces in the sintering process and the analysis of the factors affecting it.

[0084] Step 4: According to the fitness evaluation results, select the better individuals to enter the next generation;

[0085] Step 5: Perform mutation operations on individuals to generate diversity and find better solutions;

[0086] Step 6: Perform simulated annealing on each individual and conduct local search to find a better solution;

[0087] Step 7: According to the preset stopping conditions (such as the number of iterations, fitness threshold, etc.), determine whether the conditions for stopping the generation are met;

[0088] Step 8: Return the optimal individual as the optimal solution for workpiece placement, and perform simulation and actual verification;

[0089] Fig.14 This is a schematic diagram of the comparison curve between the simulated temperature and the actual test temperature. The curve can be used to draw the conclusion that the average relative error between the simulation and the actual measurement is less than 10%, proving that the simulation is highly accurate. Fig.15 As shown in the figure, the temperature uniformity decreases with the increase of the thickness of the lower support plate. Therefore, reducing the thickness of the lower support plate while meeting the strength requirements can improve the temperature uniformity in the furnace and the temperature uniformity of the workpiece. Therefore, the lower support plate should be 30mm thick as the lower support plate in the sintering process. Fig.11The tubular workpieces on the third layer of workpiece support devices are taken as analysis objects. The leftmost tubular workpiece on the first layer is workpiece 1, and the rightmost tubular workpiece is workpiece 1. The leftmost tubular workpiece on the second layer is workpiece 6, and the rightmost tubular workpiece is workpiece 10. Figure 16 to Figure 18 It can be concluded that as the thickness of the lower support plate increases, the temperature uniformity in the furnace, the temperature difference of the workpiece and the temperature difference on the workpiece all increase.

[0090] Fig.19 for Fig.11 Comparison of the temperature differences between the 10 workpieces before and after optimization shows that the gap between the two is large at the beginning of heating, but after the first insulation stage, the temperature uniformity after optimization is better than the original support plate thickness, and the temperature uniformity is increased by an average of 2.8K.

[0091] Fig. 20 For the workpiece temperature difference, Fig.21 is the temperature difference of the measuring point, Fig. 20 by Fig.11 Taking workpiece 5 as an example, the temperature difference before and after optimization, that is, the temperature uniformity of workpiece 5 after optimization, is significantly improved. At the end of sintering, the temperature difference is reduced by 2.1K. Fig.21 As shown in the figure, the temperature difference of the measuring points before and after optimization is significantly reduced, and the maximum is at the sintering end point, where the temperature difference increases by 8.1K.

[0092] The present invention utilizes a method combining heat transfer simulation and genetic algorithm to effectively improve the temperature uniformity of workpieces in a furnace. The genetic algorithm has a powerful global search capability and can find the global optimal solution in a complex search space. It is suitable for nonlinear, non-convex, multi-peak and other complex function optimization problems. It can be implemented in parallel and can search for the optimal solution faster in a multi-processor or distributed environment. Prior knowledge can be added to guide the search, thereby improving the search efficiency and having strong adaptability. Heat transfer simulation can handle dangerous environments such as high temperature and high pressure and problems such as extraordinary size, while genetic algorithm can solve complex optimization problems. The combination of the two can handle more complex problems. Combining heat transfer simulation and genetic algorithm can improve the robustness of the optimization process and reduce dependence on initial conditions.

[0093] Based on the above experimental analysis, the present invention studies the influence of the thickness of the support plate at different positions on the temperature uniformity in the vacuum sintering furnace and the temperature uniformity of the workpiece, provides a reference for the placement of the workpiece in the vacuum sintering furnace, meets the production process requirements of the vacuum sintering furnace, improves the temperature uniformity of the workpiece and the furnace to improve the sintering quality of the workpiece. Compared with the prior art, the technical solution proposed in this embodiment establishes the influence of the thickness of the graphite support plate of different tooling in the furnace on the temperature field of the workpiece in the furnace. By optimizing the thickness of the graphite support plate at different positions, the thickness of the graphite support plate at the upper and lower sides is selected as 10, 30, and 80 mm respectively as the most suitable thickness, and the average temperature of the workpiece is increased by 2.8K.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope defined by the claims of the present invention.

Claims

1. A workpiece support device for a vacuum sintering furnace, characterized in that: It includes a side support plate, a lower support plate, a clamping device, a temperature measuring device and a level measuring device; The lower support plate is provided with a plurality of slide grooves in parallel, the clamping device is slidably connected in the slide grooves, and a side support plate is provided on the lower support plate through a lower clamping adjustment bolt. The side support plate is perpendicular to the clamping device along the moving direction of the slide groove and is used for limiting the movement of the clamping device; The clamping device comprises two clamping arms arranged opposite to each other, used for clamping the tubular workpiece, the lower clamping bolt penetrates from the bottom end of the lower support plate and is screwed on the clamping arm, the two clamping arms are arranged along the moving direction of the slide slot, and the distance between the two clamping arms is adjusted by adjusting the position of the lower clamping bolt, so as to clamp tubular workpieces of different diameters; The temperature measuring device includes a temperature measuring ring, an infrared thermometer and a cylinder. The side support plate, the lower support plate and the clamping device are provided with a temperature measuring ring mounting hole. The temperature measuring ring is installed on the temperature measuring ring mounting hole. The infrared thermometer is installed in the infrared thermometer mounting hole reserved on the side of the side support plate and is connected to the cylinder outside the vacuum sintering furnace through an adjustable connecting rod. The level measuring device includes an infrared level and a level calibration bolt. The infrared level is installed on the lower support plate just below the infrared thermometer installation hole, and the level calibration bolt is evenly screwed under the lower support plate along the horizontal direction of the side support plate.

2. A vacuum sintering furnace workpiece support device according to claim 1, characterized in that: The clamping arm comprises a clamping bolt, an upper clamping head and a lower clamping head. The clamping bolt is made of graphite material. The lower clamping head is screwed on the lower support plate. The upper clamping head and the lower clamping head are screwed with the clamping bolt. By adjusting the positions of the upper and lower clamping heads on the clamping bolt, tubular workpieces with different diameters can be clamped.

3. A workpiece support device for a vacuum sintering furnace according to claim 1, characterized in that: The temperature measuring ring is used to obtain the temperature uniformity of the sintering process at different positions, and the final sintering temperature is determined by using the deformation law of the temperature measuring ring.

4. A workpiece support device for a vacuum sintering furnace according to claim 1, characterized in that: The infrared thermometer moves vertically along the side support plate to measure the temperature of the tube-shaped workpiece. As the temperature rises, the infrared thermometer can be retracted by the moving cylinder to ensure stable use of the infrared thermometer.

5. The workpiece support device for a vacuum sintering furnace according to claim 1, characterized in that: The horizontal measuring device is used to measure the horizontality of the workpiece and the supporting device during the workpiece placement process, and to adjust the horizontality of the workpiece and the supporting device by adjusting the length of the horizontal calibration bolt to ensure that the workpiece and the supporting device are in a horizontal state.

6. A method for optimizing the placement of workpieces in a vacuum sintering furnace, based on a workpiece support device for a vacuum sintering furnace, characterized in that: The specific steps include: Step 1: Establish the thermal radiation and heat conduction model of vacuum sintering process according to the vacuum furnace parameters; Step 2: Set the population size, crossover rate, and mutation rate of the genetic algorithm, and randomly generate an initial population representing possible solutions. Each individual in the population represents a way to place the workpiece. Step 3: Use user-defined functions to control the process temperature and power, and according to the sintering temperature rise process curve, obtain the temperature distribution in the vacuum sintering furnace and the temperature of each point on the workpiece, simulate the entire heating process, and establish a soft measurement method for the workpiece temperature through simulation to obtain the temperature uniformity of different positions of workpieces with different placement methods. Calculate the heating efficiency of each workpiece placement method and the temperature uniformity in the furnace and the workpiece as a fitness evaluation; Step 4: According to the fitness evaluation results, select the better individuals to enter the next generation; Step 5: Perform mutation operations on individuals to generate diversity and find better solutions; Step 6: Perform simulated annealing on each individual and conduct local search to find a better solution; Step 7: Determine whether the conditions for stopping the generation selection are met according to the preset stopping conditions; Step 8: Return the best individual as the optimal solution for workpiece placement, and perform simulation and actual verification.

7. The method for optimizing the placement of workpieces in a vacuum sintering furnace according to claim 6, characterized in that: The parameters that affect the placement of workpieces in the vacuum sintering furnace are the compactness of the workpiece placement, the thickness of the upper support plate, the thickness of the side support plate in the workpiece support device, and the thickness of the lower support plate.

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