METHOD FOR PRODUCING CERAMIC SHELLS USED FOR PRECISION CASTING

Abstract

The invention proposes a method for producing ceramic shells for precision casting. This method includes the following steps: S1, frosting the outside of the wax sample with corresponding layers of ceramic shell slurry, one layer at a time, where the ceramic shell is dried at the corresponding layer after each frosting of the ceramic shell slurry is completed; S2, placing the ceramic shells at each corresponding layer into a vacuum rapid drying system for rapid vacuum drying, and after the drying of the ceramic shell at that layer is completed, frosting the ceramic shell with the next layer of ceramic shell slurry, during which, during the rapid vacuum drying process, image data of the dried ceramic shell is obtained and analyzed to determine the position, orientation, and depth of the wormhole in the dried ceramic shell. This data is sent to a fan control module, which performs positional fan control analysis.The orientation and depth of the wormholes in the dried ceramic shell and the start-stop and / or control parameters of each fan unit are determined according to the analysis results, and the drying time of all parts of the intact ceramic shell tends to be identical by vacuuming the drying chamber and / or restoring chamber pressure and controlling the start-stop and / or control parameters of all fan units; and S3, for the completion of drying the ceramic shell in all layers to obtain a ceramic shell for precision casting. Based on retaining the inherent advantages of thick mud ceramic shells, this production method effectively overcomes the existing problems in thick mud ceramic shells.

Description

A method for preparing a ceramic shell for precision casting Technical Field

[0001] The present invention relates to the technical field of precision casting, in particular to a method for preparing and drying a ceramic shell for precision casting. Background Art

[0002] Precision casting is a casting method that, compared to traditional casting processes, can achieve relatively accurate shapes and high casting precision. The precision casting process is as follows: First, a wax mold is made. This wax mold matches the size and shape of the desired product to be cast. Then, a ceramic shell is formed on the surface of the wax mold. Subsequently, the ceramic shell is dewaxed (the wax mold inside is melted and removed). Finally, the metal material is poured into the dewaxed ceramic shell. After the metal material cools and solidifies, the ceramic shell is crushed and removed, resulting in the desired casting.

[0003] In the aforementioned process, the production of the ceramic shell is crucial; its quality determines the quality of the casting. Currently, the most commonly used method for ceramic shell production is the shell mold method, specifically the water-soluble silica sol method. This method uses refractory materials to prepare different slurries and sand. Layers of slurry and sand are gradually accumulated on the surface of the wax mold to create the desired thickness of the ceramic shell. Therefore, the ceramic shell can be structurally divided into a surface layer, a transition layer (second layer), a support layer (back layer), and a sealing layer. The surface layer, transition layer, and sealing layer each consist of only one layer, while the support layer typically has multiple layers.

[0004] According to the concentration of the ceramic shell slurry during the preparation process, it is generally divided into thick slurry ceramic shell and thin slurry ceramic shell. As the name suggests, the ceramic shell slurry concentration of thick slurry ceramic shell is higher. Compared with thin slurry ceramic shell, the main advantages of thick slurry ceramic shell are:

[0005] 1. Each layer of the ceramic shell is thicker and has a higher supporting force. Therefore, fewer layers of thick slurry ceramic shells can achieve the same supporting force as thin slurry ceramic shells that require more layers, reducing the complexity of the process.

[0006] 2. The surface density of the ceramic shell is high, and the problem of casting penetration rarely occurs.

[0007] However, in most cases, thin slurry ware shells are still chosen when preparing ware shells using existing technologies. The main reason is that thick slurry ware shells have the following difficult-to-overcome problems:

[0008] 1. Due to the high concentration of the slurry, it is difficult for the sand to penetrate the entire slurry layer during sand covering, resulting in an uneven state in which the sand is aggregated on the surface but missing inside. This makes the strength of the ceramic shell uneven, and the sand-free part is prone to cracking when drying, which can cause puncture and fire in the casting.

[0009] 2. The air permeability of the ceramic shell is poor, which will cause poor exhaust during casting, and easily cause grooves on the surface of the casting due to bubbles, affecting the casting accuracy.

[0010] 3. A high breaking strength coefficient. While a high breaking strength coefficient is beneficial for preparing a dense surface layer and providing sufficient support during the casting process, the high overall breaking strength coefficient of the ceramic shell can make it difficult to remove the shell after casting. Using violent shell breaking can easily damage the casting, resulting in a decrease in casting accuracy. Therefore, while ensuring that the ceramic shell has sufficient support, lowering the breaking strength coefficient of the ceramic shell has always been a technical improvement direction in the field of precision casting.

[0011] 4. Although the water content of thick slurry ceramic shell is low, the resistance to the movement of water molecules is large. Therefore, its drying time is even longer than that of thin slurry. When it comes to castings with deep holes, it is difficult to make the drying time of different parts of the ceramic shell tend to be consistent. Often, when the deep hole part of the ceramic shell is dried, the rest of the ceramic shell may have been over-dried, causing the ceramic shell to crack.

[0012] However, due to the limited expansion of a single layer of slurry ceramic shell, when the breaking strength coefficient is low, the thickness of the ceramic shell has to be increased by adding more layers to provide sufficient support. This requires multiple slurrying processes, which increases the complexity of the process. The drying time of the ceramic shell increases with the number of layers, and the preparation efficiency decreases significantly. At the same time, when deep-hole castings are involved, how to make the drying time of each part of the slurry ceramic shell tend to be consistent and complete the drying in a relatively short time is also a technical problem that needs to be overcome.

[0013] Summary of the Invention

[0014] In view of the problems existing in the prior art, the present invention provides a method for preparing a ceramic shell for precision casting, comprising:

[0015] S1. Apply a corresponding number of layers of ceramic shell slurry to the outside of the wax mold layer by layer, and obtain the corresponding layers of ceramic shell to be dried after each application of the ceramic shell slurry.

[0016] S2. Each corresponding layer of the ceramic shell to be dried is placed in a vacuum rapid drying system for vacuum rapid drying. After the drying of the ceramic shell of the layer is completed, the ceramic shell slurry of the next layer is applied.

[0017] During the vacuum rapid drying process, the model information of the ceramic shell to be dried is first obtained, and then the control parameters of the blowers on different sides of the ceramic shell to be dried are adjusted according to the model information, so that the drying time of each part of the ceramic shell to be dried tends to be consistent.

[0018] S3. After all layers of the ceramic shell are dried, the ceramic shell for precision casting is obtained.

[0019] Furthermore, the vacuum rapid drying system includes a vacuum drying chamber, a vacuum pump, and a control system. The vacuum pump evacuates the vacuum drying chamber. A drying rack is provided within the vacuum drying chamber, and the ceramic shell to be dried is placed on the drying rack for drying. At least two sets of fans with different wind directions are provided within the vacuum drying chamber, surrounding the drying rack.

[0020] The control system includes a vacuum drying control module and a fan group control module. The vacuum drying control module controls the vacuum drying chamber to evacuate and / or restore the chamber pressure, while the fan group control module controls the on / off and / or control parameters of all fan groups to ensure that the drying time of each part of the ceramic shell to be dried is consistent.

[0021] Furthermore, inside the vacuum drying chamber, a first blower unit is provided at the top of the drying rack, a second blower unit is provided at the bottom of the drying rack, a third blower unit is provided on the switch door of the vacuum drying chamber along the cross section of the vacuum drying chamber, and a fourth blower unit and a fifth blower unit are respectively provided on both sides of the drying rack along the axial direction of the vacuum drying chamber.

[0022] Furthermore, an adjustable component is provided in the vacuum drying chamber on the side opposite to the third blower unit, and the adjustable component is a condenser or a sixth blower unit.

[0023] Optionally, the vacuum drying chamber is provided with a controller component that receives a control signal and sends it to a fan group control module to control the start and stop of each fan group and / or control parameters.

[0024] Furthermore, the controller includes at least one of a knob controller, a button controller, a touch screen controller, and a toggle switch.

[0025] Optionally, a three-dimensional detection mechanism is provided inside the vacuum drying chamber, and the three-dimensional detection mechanism drives the scanning device to move along the X-axis, the Y-axis, and the Z-axis.

[0026] The scanning device at least includes: an imaging device, which is used to obtain image data of the ceramic shell to be dried.

[0027] The control system includes a ceramic shell analysis module. The module acquires image data of the ceramic shell to be dried and performs model structure analysis to determine the location, orientation, and depth of the deep holes in the ceramic shell to be dried. The module then transmits this information to a fan unit control module. The fan unit control module analyzes the location, orientation, and depth of the deep holes in the ceramic shell to be dried and controls the on / off and / or control parameters of each fan unit based on the analysis results.

[0028] Furthermore, the three-dimensional detection mechanism includes: two X-axis guide rails arranged horizontally along the axial direction of the vacuum drying chamber, which are parallel to each other and are respectively located on both sides of the drying rack, and a Y-axis guide rail arranged horizontally along the cross-section of the vacuum drying chamber. The two X-axis guide rails are respectively provided with a first displacement device that can be displaced along the X-axis guide rail, and the Y-axis guide rail is fixed between the two first displacement devices and is driven by the two first displacement devices to be displaced along the X-axis guide rail. The Y-axis guide rail is provided with a second displacement device that can be displaced along the Y-axis guide rail. The two displacement devices are provided with an electric-controlled telescopic device that can be extended and retracted along the Z-axis direction in the vertical direction. The end of the telescopic end of the electric-controlled telescopic device is fixed with a scanning device through an electric-controlled pan-tilt head. The first displacement device, the second displacement device, the electric-controlled telescopic device, and the electric-controlled pan-tilt head are respectively connected to the control system signal.

[0029] Furthermore, the control system includes a scanning device control module. The scanning device control module is used to control the movement of the two first displacement devices, the second displacement device, the electrically controlled telescopic device, and the electrically controlled pan / tilt stage, so that the scanning device can perform omnidirectional photography / scanning of the ceramic shell to be dried to obtain images / scanning data of the ceramic shell to be dried.

[0030] Furthermore, the model structure analysis includes image analysis:

[0031] First, the outer contour model data, deep hole position data, and deep hole depth data of the ceramic shell to be dried are obtained.

[0032] Then, the acquired image data is compared with the outer contour model data to determine the spatial orientation of the ceramic shell to be dried currently hanging in the vacuum drying chamber.

[0033] Finally, the current deep hole position and orientation of the ceramic shell to be dried are determined according to the spatial orientation of the ceramic shell to be dried, and the deep hole position, orientation and depth data corresponding to the deep hole of the ceramic shell to be dried are output.

[0034] Furthermore, the scanning device further comprises: a scanning distance measuring device, which is used to measure the distance between the ceramic shell to be dried and the scanning device in real time.

[0035] The model structure analysis includes:

[0036] Step 1.1 The scanning distance measuring device performs a full-scale scan on the surface n of the ceramic shell to be dried according to a preset route, and obtains a distance measurement data set G of all scanning points on the surface n relative to the scanning distance measuring device. n .

[0037] Step 1.2 The ranging data set G n The end points are connected to obtain the digital surface m of the ceramic shell surface n to be dried.

[0038] Step 1.3: Graphically analyze the digital surface m of the ceramic shell to be dried in combination with the image data to determine the basic surface, convex surface, and concave surface of the digital surface m.

[0039] Step 1.4 Calculate the difference C between each distance measurement point on the groove surface and each distance measurement point on the adjacent basic surface of the groove mk-b , where mk is the groove numbered k on the digital surface m, and b is the separate number of the distance measurement point in the groove mk.

[0040] Step 1.5 Take C mk-b >K2 is a deep hole, take C mk-b >K3 is a through hole. Among them, K2 is a preset deep hole judgment threshold, and K3 is the model width, model length, or model height corresponding to the surface n of the ceramic shell to be dried.

[0041] Step 1.6 Count the positions W of all deep holes on the digital surface m of the ceramic shell to be dried mc The depth H corresponding to each deep hole mc , where c is the natural number of the deep hole on the digital surface m.

[0042] Step 1.7 Repeat steps 1.1 to 1.6 until all the deep holes on the surface of the ceramic shell to be dried can be scanned. mc , depth H mc Statistics are completed, and the deep hole direction X is determined based on the surface n where the deep hole is located mc .

[0043] Step 1.8 Output the position W of the deep holes on all surfaces of the ceramic shell to be dried mc , depth H mc , towards X mc data.

[0044] Furthermore, the method for obtaining the base surface, the convex surface and the concave surface in step 1.3 includes:

[0045] Step 1.3.1: Obtain image data corresponding to the digital surface m of the ceramic shell to be dried, and obtain the image surface R by splicing the image data.

[0046] Step 1.3.2 performs element recognition on the image surface R to obtain element regions rn-m on the image surface R, where rn is the sequential number of the element regions in the digital surface m.

[0047] Step 1.3.3: Adjust the digital surface m to have the same orientation and similar size as the image surface R.

[0048] In step 1.3.4, the element region rc-m with the largest continuous area is taken as the base surface, and the rc-m belongs to rn-m.

[0049] Step 1.3.5 obtains the distance measurement point data of each non-basic surface feature area, where the feature area distance measurement points that are greater than the distance to the adjacent basic surface distance measurement points are groove points, and the feature area distance measurement points that are less than the distance to the adjacent basic surface distance measurement points are convex points.

[0050] In step 1.3.6, the adjacent groove points and convex points are connected to form groove surfaces and convex surfaces based on the element area.

[0051] Furthermore, the three-dimensional detection mechanism is equipped with an electrically controlled telescopic device, and a scanning device is fixed to the telescopic end of the electrically controlled telescopic device through an electrically controlled pan-tilt platform.

[0052] Optionally, the electronically controlled pan / tilt head includes: a fixed platform secured to the electronically controlled telescopic device; and a rotating platform rotatably connected to the fixed platform and capable of rotating relative to the fixed platform along a vertical axis. The rotating platform is rotatably connected to the fixed end of a second electronically controlled telescopic device via a speed reducer, and the speed reducer controls the rotation of the second electronically controlled telescopic device along a horizontal axis. The scanning device is secured to the telescopic end of the second electronically controlled telescopic device.

[0053] Furthermore, the model structure analysis also includes:

[0054] Step 2.1: According to the deep hole position, control the scanning distance measuring device to move to the deep hole position.

[0055] Step 2.2: Acquire multiple deep hole depth measurement data by adjusting the orientation of the scanning distance measuring device relative to the deep hole.

[0056] Step 2.3 Use the deepest depth measurement data to correct the original deep hole depth data H m-c , get the corrected data H m-c `.

[0057] Furthermore, the scanning device further comprises an infrared temperature measuring device. The control system comprises a drying process analysis module, which obtains the measurement data of the infrared temperature measuring device to analyze the drying process to determine whether the ceramic shell to be dried is completely dried.

[0058] The drying process analysis includes: measuring the temperature T inside the deep hole regularly or continuously. v - Curve Q of drying time t v , when Q v When all curve segments that conform to the preset curve law appear, it indicates that the drying of the ceramic shell to be dried is completed. Wherein v is the natural number of all deep holes in the ceramic shell to be dried.

[0059] Furthermore, the preset curve pattern includes: the temperature T inside the deep hole gradually decreases from the initial drying temperature T1 to the temperature T2 over the drying time, and then gradually increases to the drying environment temperature T3 over the drying time. When the temperature T of the deep hole of the ceramic shell to be dried undergoes the process of T1-T2-T3 and maintains the drying environment temperature T3 for a preset time U, it is determined that the drying is complete. The initial drying temperature T1 is 22-26°C, the temperature T2 is 5-7°C lower than the temperature T1, and the drying environment temperature T3 is 24±1°C.

[0060] Furthermore, when there are multiple ceramic shells to be dried in the same batch, the temperature of each deep hole of each ceramic shell to be dried is detected one by one. When more than L% of the ceramic shells to be dried are dried, it is determined that the drying of the entire batch of ceramic shells to be dried is completed. The L%=(L g-d ) / (L 0-d )*100%, where L g-d is the number of ceramic shells to be dried after batch d drying, L 0-d is the number of all ceramic shells to be dried in batch d. The value of L% is: 100% ≥ L% ≥ E%. Where E is the preset threshold value of the minimum drying completion percentage of all ceramic shells to be dried in batch d.

[0061] Furthermore, the fan group control analysis includes:

[0062] For all fan units P facing the ceramic shell to be dried with deep holes on the surface, the following method is adopted:

[0063] Step 3.1 Obtain the total number of deep holes D0 of the ceramic shell to be dried, and obtain the total number of deep holes D on the surface of the ceramic shell to be dried facing the fan group p. p ; The p is the number of the fan unit set on different sides of the vacuum drying chamber;

[0064] Step 3.2 Calculate k S-p % = D p / D0*100%, the k S-p % is the control parameter of fan group p;

[0065] Step 3.3 Repeat steps 3.1 to 3.2 to obtain k for all fan groups S-p %;

[0066] For all fan units P facing the ceramic shell to be dried without deep holes, the following method is adopted:

[0067] Calculate k F-p % = [1-D0 / (D 0+1 )]*100%, the k F-p % is the control parameter of fan group p;

[0068] The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

[0069] Furthermore, the fan group control analysis includes:

[0070] For all fan units P facing the ceramic shell to be dried with deep holes on the surface, the following method is adopted:

[0071] Step 4.1 Obtain the total number of deep holes D0 of the ceramic shell to be dried, and obtain the total number of deep holes D on the surface of the ceramic shell to be dried facing the fan group p. p ; The p is the number of the fan unit set on different sides of the vacuum drying chamber;

[0072] Step 4.2 According to D0 and D p The number of k is obtained from the control parameter database S-p %; the k S-p % is the control parameter of fan group p;

[0073] Step 4.3 Repeat steps 4.1 to 4.2 to obtain the k of all fan groups. S-p %;

[0074] For all fan units P facing the ceramic shell to be dried without deep holes, the following method is adopted:

[0075] According to the total number of deep holes D0 in the ceramic shell to be dried, k is obtained from the control parameter database. F-p %; the k F-p % is the control parameter of fan group p;

[0076] The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

[0077] Furthermore, k is entered into the control parameter database. S-p % and k F-p % of the methods include:

[0078] Step 5.1: Simulate the same position and orientation of the fan unit as that of the target vacuum drying chamber 1 in the simulation device.

[0079] Step 5.2 Preset the deep hole distribution of different ceramic shells to be dried for drying training, and determine the control parameter k of each fan group p relative to full load corresponding to the optimal drying time under each deep hole distribution S-p % and k F-p %; the deep hole distribution includes: deep hole direction and number; the optimal drying time is the shortest time for the deep holes and the surface of the ceramic shell 4 to be dried to complete the synchronous drying;

[0080] Step 5.3 Repeat step 5.2 until the deep hole distribution under normal conditions is trained and D0-D p —k S-p %—k F-p % of the deep hole-control parameter relationship group and store it in the control parameter database.

[0081] Furthermore, at least two fans are arranged in the fan group, and the fan group control module controls the fans in each fan group synchronously or individually.

[0082] Furthermore, the fan group control analysis also includes:

[0083] Step 6.1 constructs a three-dimensional coordinate system based on the scanning starting point preset by the scanning device.

[0084] Step 6.2: Record the three-dimensional coordinate points in space during the displacement of the scanning device, and mark the three-dimensional coordinate points of the deep hole position, direction and depth of the ceramic shell to be dried during the model structure analysis.

[0085] Step 6.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p.

[0086] Step 6.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up .

[0087] Step 6.5 Calculate k up-e %=(D up-e / D up )*k S-p %.

[0088] The fan group control module obtains the k of each fan in the fan group p. up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % Run. For D up-e =0, the fan operates at the lowest power.

[0089] Furthermore, the fan group control analysis includes:

[0090] Step 7.1 constructs a three-dimensional coordinate system based on the scanning starting point preset by the scanning device.

[0091] Step 7.2: Record the three-dimensional coordinate points in space during the displacement of the scanning device, and mark the three-dimensional coordinate points of the deep hole position, direction and depth of the ceramic shell to be dried during the model structure analysis.

[0092] Step 7.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p.

[0093] Step 7.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up .

[0094] Step 7.5 According to D up and D up-e Get the k value of the corresponding fan from the control parameter database up-e %, the k up-e % is the control parameter of the fan numbered e in the fan group p.

[0095] The fan group control module obtains the k of each fan in the fan group p. up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % to run.

[0096] Furthermore, the k up-e Methods for obtaining % include:

[0097] Step 8.1: Simulate the same fan unit position and orientation as the target vacuum drying chamber in the simulation device.

[0098] Step 8.2 Preset the deep hole distribution of different ceramic shells to be dried for drying training, and determine the operating ratio k of each fan in each fan group p when relatively fully loaded corresponding to the optimal drying time under each deep hole distribution. up-e The deep hole distribution includes: the direction and number of the deep holes. The optimal drying time is the shortest time for the deep holes and the surface layer of the ceramic shell to be dried to be dried synchronously.

[0099] Step 8.3 Repeat step 8.2 until the deep hole distribution under normal conditions is trained and D up —D up-e —k up-e% of the deep hole-control parameter relationship group and store it in the control parameter database.

[0100] Furthermore, the vacuum rapid drying system includes: a first data transmission module, a local database module and a remote system module.

[0101] The first data transmission module is signal-connected to the remote system module via a signal line connection or a wireless network connection.

[0102] The local database module is used as a control parameter database to store relevant deep hole-control parameter relationship groups.

[0103] The remote system module collects the deep hole-control parameter relationship group and operation result data of each vacuum rapid drying system through the first data transmission module, and selects the deep hole-control parameter relationship group corresponding to the best operation result from the same deep hole relationship; and based on authorization permission and / or instructions and / or automatic synchronization, the deep hole-control parameter relationship group corresponding to the best operation result is centralized through the remote system module and then synchronized to the local database module of each vacuum rapid drying system through the first data transmission module, or directly synchronized to the local database module of each vacuum rapid drying system through the first data transmission module.

[0104] When the vacuum rapid drying system calls the deep hole-control parameter relationship group in the local database module, if a new optimal deep hole-control parameter relationship group exists, the new optimal deep hole-control parameter relationship group is called first.

[0105] Furthermore, the vacuum rapid drying system includes a second data transmission module.

[0106] The remote system module is connected to the control system signal of the vacuum rapid drying system through a second data transmission module in the form of a signal line connection or a wireless network connection, so as to send remote control instructions to the control system and / or obtain control instructions issued by the control system and / or obtain operating status parameters of various electronic control devices in the vacuum rapid drying system.

[0107] The execution priority of the remote control instruction issued by the remote system module is higher than the execution priority of the control instruction issued by the control system.

[0108] Furthermore, the scanning device includes a thermal imager. The method for making the drying time of each part of the ceramic shell to be dried tend to be consistent includes:

[0109] Step 9.1 During the drying process of the ceramic shell to be dried, the thermal imager and the scanning device take real-time thermal images of the ceramic shell to be dried and send the images to the control system.

[0110] Step 9.2: The control system determines, based on the heat distribution in the thermal imaging image, whether there is an area T with a high / low temperature difference exceeding a preset temperature difference threshold when the drying time exceeds the preset first drying time. If there is an area T, the control system performs the following determination and operation:

[0111] When the temperature of the low-temperature area of ​​region T is lower than the preset low-temperature threshold, the operating power of the fan group corresponding to region T is reduced.

[0112] When the temperature of the high temperature area of ​​region T is higher than the preset high temperature threshold, the operating power of the fan group corresponding to region T is increased.

[0113] When the existence time of area T exceeds the preset time threshold, and the temperature of the low temperature area of ​​area T is higher than the preset low temperature threshold, and the temperature of the high temperature area of ​​area T is lower than the preset high temperature threshold, the operating power of the fan group corresponding to area T is increased.

[0114] Furthermore, the preset low temperature threshold is 12-15° C., the preset high temperature threshold is 26-28° C., the preset first drying time is 1-3 minutes, and the preset time threshold is 30-60 seconds.

[0115] Furthermore, the vacuum rapid drying method includes:

[0116] When drying the surface layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 750-720 mmHg within 5 seconds. Then, restore the vacuum level from 750-720 mmHg to atmospheric pressure within 5 seconds. Repeat this process until the surface layer is completely dried.

[0117] When drying the transition layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 720-680 mmHg within 7 seconds. Then, restore the vacuum level from 720-680 mmHg to atmospheric pressure within 7 seconds. Repeat this process until the transition layer is completely dried.

[0118] When drying the support layer, the following steps are included:

[0119] Step 10.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-20 mmHg within 30 seconds.

[0120] Step 10.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0121] Step 10.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds.

[0122] Step 10.4: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-20 mmHg within 30 seconds.

[0123] In step 10.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds.

[0124] Step 10.6 Repeat steps 10.4 and 10.5 until the support layer is completely dry.

[0125] When drying the sealing layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 120-90 mmHg within 40 seconds. Then, return the vacuum level of the ceramic shell to atmospheric pressure within 120 seconds. Repeat this process until the sealing layer is completely dried.

[0126] Furthermore, the support layer is provided with at least three layers in sequence from the transition layer to the sealing layer, wherein:

[0127] The inner surface of the first support layer is bonded to the outer surface of the transition layer, and the vacuum rapid drying process of the first support layer is performed, including the following steps:

[0128] Step 11.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-220 mmHg within 30 seconds.

[0129] Step 11.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0130] In step 11.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0131] In step 11.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 260-220 mmHg within 30 seconds.

[0132] In step 11.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0133] Step 11.6 Repeat steps 11.4 and 11.5 until the first layer of the support layer is dry.

[0134] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0135] Step 12.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 200-150 mmHg within 30 seconds.

[0136] Step 12.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0137] In step 12.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0138] In step 12.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 200-150 mmHg within 30 seconds.

[0139] In step 12.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0140] Step 12.6 Repeat steps 12.4 and 12.5 until the second layer of support layer is dry.

[0141] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0142] Step 13.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0143] Step 13.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0144] Step 13.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds.

[0145] Step 13.4: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0146] In step 13.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds.

[0147] Step 13.6 Repeat steps 13.4 and 13.5 until the third support layer is dry.

[0148] The inner surface of the sealing layer is in contact with the outer surface of the third layer of the supporting layer.

[0149] Furthermore, the vacuum rapid drying system includes a vacuum drying chamber, a vacuum pump, and a control system. The vacuum pump evacuates the vacuum drying chamber. The vacuum pump is connected to the vacuum drying chamber via a first connecting pipe, which is equipped with a first electrically controlled on / off valve. The vacuum drying chamber is connected to an air pipe, which is equipped with a second electrically controlled valve.

[0150] The ceramic shell to be dried is placed in a vacuum drying chamber for vacuum rapid drying.

[0151] The control system controls the opening and closing of the vacuum pump, the first electrically controlled switch valve, and the second electrically controlled valve to implement the method steps of the vacuum rapid drying process.

[0152] Furthermore, the vacuum rapid drying system further includes a vacuum tank. One end of the vacuum tank is connected to the vacuum pump via a second connecting pipe, and a third electrically controlled valve is provided on the second connecting pipe. The other end of the vacuum tank is connected to the vacuum drying chamber via a third connecting pipe, and a fourth electrically controlled valve is provided on the third connecting pipe.

[0153] Furthermore, when vacuum drying the support layer and the sealing layer, a transient pressure reduction operation is also included. The transient pressure reduction operation includes:

[0154] First, before reducing the pressure, close the fourth electronically controlled valve and evacuate the vacuum tank to a low vacuum state in advance.

[0155] Then, when the pressure is reduced, the fourth electrically controlled valve is opened to connect the vacuum drying chamber with the vacuum tank, and the pressure is instantly reduced to the equilibrium low pressure within 0.5 seconds.

[0156] Finally, the vacuum pump simultaneously extracts the gaseous components in the vacuum tank and the vacuum drying chamber, so that the vacuum degree in the vacuum drying chamber meets the preset target, and then closes the fourth electrically controlled valve and the first electrically controlled switch valve. At the same time, the vacuum pump continues to extract the gaseous components in the vacuum tank to the vacuum tank to a low vacuum state.

[0157] Furthermore, the vacuum drying of the support layer and the sealing layer also includes an instantaneous pressure reduction operation:

[0158] The vacuum rapid drying process for the first layer of the support layer includes the following steps:

[0159] Step 14.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank maintains vacuum.

[0160] Step 14.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank.

[0161] In step 14.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank continues to be evacuated.

[0162] In step 14.4, an instantaneous pressure reduction operation is performed, and the vacuum degree of the ceramic shell environment to be dried is reduced from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank is kept evacuated.

[0163] In step 14.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank continues to be evacuated.

[0164] Step 14.6 Repeat steps 14.4 and 14.5 until the first layer of the support layer is dry.

[0165] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0166] In step 15.1, an instantaneous pressure reduction operation is performed, and the vacuum degree of the ceramic shell to be dried is reduced from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank is kept evacuated.

[0167] Step 15.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes, and continue to evacuate the vacuum tank.

[0168] In step 15.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank continues to be evacuated.

[0169] In step 15.4, an instantaneous pressure reduction operation is performed, and the vacuum degree of the ceramic shell environment to be dried is reduced from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank is kept evacuated.

[0170] In step 15.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank continues to be evacuated.

[0171] Step 15.6 Repeat steps 15.4 and 15.5 until the second layer of the support layer is dry.

[0172] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0173] Step 16.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank maintains vacuum.

[0174] Step 16.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes, and continue to evacuate the vacuum tank.

[0175] In step 16.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank continues to be evacuated.

[0176] In step 16.4, an instantaneous pressure reduction operation is performed, and the vacuum degree of the ceramic shell environment to be dried is reduced from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank is kept evacuated.

[0177] In step 16.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank continues to be evacuated.

[0178] Step 16.6 Repeat steps 16.4 and 16.5 until the third layer of support layer is dry.

[0179] The inner surface of the sealing layer is attached to the outer surface of the third layer of the support layer, and the vacuum rapid drying process of the sealing layer is performed, which includes the following steps:

[0180] In step 17.1, an instantaneous pressure reduction operation is performed, and the vacuum degree of the ceramic shell environment to be dried is reduced from the instantaneous equilibrium low pressure to 260-220 mmHg within 35 seconds, while the vacuum tank is kept evacuated.

[0181] In step 17.2, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 120 seconds, and the vacuum tank continues to be evacuated.

[0182] Step 17.3 Repeat steps 17.1 and 17.2 until the sealing layer is completely dry.

[0183] The present invention has at least one of the following beneficial effects:

[0184] 1. The present invention retains the inherent advantages of thick slurry ceramic shells, effectively overcomes the problems existing in thick slurry ceramic shells, and provides a thick slurry ceramic shell with excellent layer thickness, good air permeability, uniform sand covering, and excellent breaking strength coefficient.

[0185] 2. The present invention can make the drying time of each part of the ceramic shell tend to be consistent through manual control or automatic analysis and control. Especially when it comes to deep hole structures where uniform drying is more difficult, the drying time of the deep hole and the surface can be effectively balanced to obtain the optimal result.

[0186] 3. The present invention has remote control and remote sharing capabilities, and can synchronize the optimal fan control method to all vacuum drying systems, significantly reducing the trial and error costs of enterprises when drying various types of ceramic shells and improving enterprise benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0187] FIG1 is a schematic structural diagram of a vacuum rapid drying system according to the present invention;

[0188] FIG2 is a schematic diagram showing a partial structure of a vacuum drying chamber according to the present invention;

[0189] FIG3 is a schematic diagram showing a partial structure of a three-dimensional detection mechanism according to the present invention;

[0190] FIG4 is a schematic diagram showing the Z-axis structure of the three-dimensional detection mechanism of the present invention;

[0191] FIG5 is a schematic diagram showing the structure of an electronically controlled pan / tilt platform according to the present invention;

[0192] FIG6 is a schematic structural diagram of a scanning device according to the present invention;

[0193] FIG7 is a schematic diagram of an exemplary ceramic shell structure;

[0194] FIG8 is a schematic diagram showing the scanning device of the present invention scanning the ceramic shell shown in FIG7 ;

[0195] FIG9 is a schematic diagram of a temperature-time curve showing a preset curve rule for determining whether drying is complete according to the present invention;

[0196] FIG10 is a schematic diagram of another exemplary ceramic shell structure;

[0197] In the figure: 1. Vacuum drying chamber; 101. First blower unit; 102. Second blower unit; 103. Third blower unit; 104. Fourth blower unit; 105. Fifth blower unit; 106. Air pipe; 107. Second electric control valve; 108. Adjustable member; 2. Three-dimensional detection mechanism; 201. X-axis guide rail; 202. Y-axis guide rail; 203. First displacement device; 204. Second displacement device; 205. Electric-controlled telescopic device; 206. Electric-controlled pan / tilt platform; 2061. Fixed platform; 2062. Rotating platform; 2063. Speed ​​reduction Machine; 2064, second electrically-controlled telescopic device; 207, scanning device; 2071, camera device; 2072, thermal imager; 2073, scanning distance measuring device; 2074, infrared temperature measuring device; 3, drying rack; 301, guide rail; 302, rack support plate; 303, roller; 304, ceramic shell rack; 305, hooking groove; 4, ceramic shell to be dried; 401, deep hole; 402, holding part; 5, vacuum tank; 6, fourth electrically-controlled valve; 7, third connecting pipe; 8, vacuum pump; 9, third electrically-controlled valve; 10, first electrically-controlled switch valve; 11, hook. DETAILED DESCRIPTION

[0198] The present invention will now be described in further detail with reference to the accompanying drawings. It should be noted that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the present invention.

[0199] The present invention illustratively provides a method for preparing a ceramic shell for precision casting, comprising:

[0200] S1. Apply a corresponding number of layers of ceramic shell slurry to the outside of the wax mold layer by layer, and obtain the corresponding layers of ceramic shell to be dried after each application of the ceramic shell slurry.

[0201] S2. Each corresponding layer of the ceramic shell to be dried is placed in a vacuum rapid drying system for vacuum rapid drying. After the drying of the ceramic shell of the layer is completed, the ceramic shell slurry of the next layer is applied.

[0202] During the vacuum rapid drying process, the model information of the ceramic shell to be dried is first obtained, and then the control parameters of the blowers on different sides of the ceramic shell to be dried are adjusted according to the model information, so that the drying time of each part of the ceramic shell to be dried tends to be consistent.

[0203] S3. After all layers of the ceramic shell are dried, the ceramic shell for precision casting is obtained.

[0204] The present invention adjusts the control parameters of the blowers on different sides of the ceramic shell to be dried, so that the drying time of each part of the ceramic shell to be dried tends to be consistent. In particular, when deep hole structures are involved, which are more difficult to dry uniformly, the drying time of the deep holes and the surface can be effectively balanced.

[0205] The present invention illustratively provides a vacuum rapid drying system, as shown in Figure 1 , comprising: a vacuum drying chamber 1, a vacuum pump 8, and a control system. The vacuum pump 8 evacuates the vacuum drying chamber 1. The vacuum pump 8 is connected to the vacuum drying chamber 1 via a first connecting pipe, which is provided with a first electrically controlled on / off valve 10. An air pipe 106 is connected to the vacuum drying chamber 1, which is provided with a second electrically controlled valve 107.

[0206] The vacuum drying chamber 1 is provided with a detachable drying rack 3, on which the ceramic shell 4 to be dried can be detachably mounted. At least two sets of fans with different wind directions are provided around the drying rack 3 in the vacuum drying chamber 1.

[0207] The control system includes a vacuum drying control module and a fan unit control module. The vacuum drying control module controls the opening and closing of the vacuum pump 8, the first electrically controlled on-off valve 10, and the second electrically controlled valve 107, while the fan unit control module controls the opening and closing and / or control parameters of all fan units.

[0208] In existing vacuum drying systems, the fan units installed generally operate at a constant speed. To achieve uniform drying, the prior art, as shown in the applicant's prior patent: CN 201610416881.4, uses two sets of fan units with different directions and a ceramic shell rotating device, so that the ceramic shell rotates continuously during the drying process to receive wind, thereby improving the uniformity of the drying process. However, this method has the following problems:

[0209] 1. When drying complex components with deep holes, the problem of relatively uniform drying time between the deep holes and other parts cannot be overcome. That is, when drying complex components with deep holes, there is still a possibility that when the ceramic shell of the deep hole part is dried, the rest of the ceramic shell may have been over-dried.

[0210] 2. There is a certain centrifugal force during the rotation of the ceramic shell, which can easily cause the sand inside the ceramic shell to deviate centrifugally, especially when the slurry viscosity is low.

[0211] 3. The ceramic shell needs to be rotated continuously during the drying process, which may cause relative slippage of the ceramic shell to be dried, and further the ceramic shell may collide with or slide off the turntable, causing damage to the ceramic shell.

[0212] The vacuum drying system of the present invention can realize corresponding control of the fan unit inside the vacuum drying chamber 1 through the fan unit control module, thereby providing wind of different intensities in different lateral directions, so that the degree of wind exposure of various parts of the ceramic shell varies. The wind force on the windward side of the ceramic shell containing a deep hole structure is stronger, which is conducive to the rapid volatilization of moisture in the deep holes, while the wind force on the windward side of the ceramic shell without a deep hole structure is weaker, avoiding the excessive drying of this part of the ceramic shell, thereby making the drying time of various parts of the ceramic shell tend to be consistent.

[0213] The present invention exemplarily provides a fan group structure, as shown in Figures 1 and 3: a first blower group 101 is provided at the top of the drying rack 3 inside the vacuum drying chamber 1, a second blower group 102 is provided at the bottom of the drying rack 3, a third blower group 103 is provided on the switch door of the vacuum drying chamber 1 along the cross section of the vacuum drying chamber 1 on the drying rack 3, and a fourth blower group 104 and a fifth blower group 105 are respectively provided on both sides of the drying rack 3 along the axial direction of the vacuum drying chamber 1.

[0214] The present invention exemplarily provides an additional component, as shown in Figure 1: an adjustable component 108 is provided inside the vacuum drying chamber 1 on the opposite side of the third blower unit 103. The adjustable component 108 is a condenser or a sixth blower unit.

[0215] The present invention exemplarily provides a method for controlling a fan group, including: the vacuum drying chamber 1 is provided with a controller component. The controller component receives a control signal and sends it to a fan group control module to control the start and stop and / or control parameters of each fan group.

[0216] The present invention exemplarily provides a controller, including at least one of a knob controller, a button controller, a touch screen controller, and a toggle switch.

[0217] This method can control the operating status of the fan groups using an offline control method, that is, the controller selects whether each fan group is started and at what operating ratio. The operating ratio is the ratio of the current fan speed to the rated speed.

[0218] This method makes the overall structure of the control system relatively simple, but when drying the ceramic shell, the operator needs to observe the direction of the deep holes of the ceramic shell to be dried and control the operation ratio of each group of fans based on experience. The drying effect is highly correlated with the observation ability and work experience of the staff.

[0219] The present invention exemplarily provides a method for controlling a fan unit, as shown in Figures 1 and 2, including: a three-dimensional detection mechanism 2 is provided inside the vacuum drying chamber 1. The three-dimensional detection mechanism 2 drives a scanning device 207 to move along the X-axis, Y-axis, and Z-axis.

[0220] As shown in FIG6 , the scanning device 207 includes an imaging device 2071. The imaging device 2071 is used to obtain image data of the ceramic shell 4 to be dried.

[0221] The control system includes a ceramic shell analysis module. The module acquires image data of the ceramic shell 4 to be dried and performs a structural model analysis to determine the location, orientation, and depth of the deep holes in the ceramic shell 4 to be dried. The module then transmits this information to the fan unit control module. The fan unit control module analyzes the location, orientation, and depth of the deep holes in the ceramic shell 4 to be dried and controls the on / off and / or control parameters of each fan unit based on the analysis results.

[0222] The use of image data for analysis can relatively quickly determine the basic structure of the ceramic shell, and determine whether there are deep holes and the location and orientation of the deep holes, thereby determining the fan group facing the deep holes for the corresponding fan operation ratio control.

[0223] The present invention exemplarily provides a three-dimensional detection mechanism, as shown in Figures 1 to 4. The three-dimensional detection mechanism 2 includes: two parallel X-axis guide rails 201 arranged horizontally along the axial direction of a vacuum drying chamber 1 and located on either side of a drying rack 3; and a Y-axis guide rail 202 arranged horizontally along the transverse direction of the vacuum drying chamber 1. Each of the two X-axis guide rails 201 is provided with a first displacement device 203 capable of displacement along the X-axis guide rail 201. The Y-axis guide rail 202 is fixed between the two first displacement devices 203 and is driven by the two first displacement devices 203 to displace along the X-axis guide rail 201. A second displacement device 204 capable of displacement along the Y-axis guide rail 202 is provided on the Y-axis guide rail 202. The second displacement device 204 is vertically provided with an electrically controlled telescopic device 205 that is telescopic along the Z-axis. A scanning device 207 is secured to the telescopic end of the electrically controlled telescopic device 205 via an electrically controlled pan / tilt platform 206. The first displacement device 203 , the second displacement device 204 , the electric-controlled telescopic device 205 , and the electric-controlled pan / tilt platform 206 are respectively connected to the control system signal.

[0224] The present invention illustratively provides a control system including a scanning device control module. The scanning device control module is configured to control the movement of two first displacement devices 203, a second displacement device 204, an electrically controlled telescopic device 205, and an electrically controlled pan / tilt platform 206, so that a scanning device 207 can omnidirectionally capture / scan the ceramic shell 4 to be dried, thereby obtaining images / scanning data of the ceramic shell 4 to be dried.

[0225] The scanning device control module can control the three-dimensional detection mechanism of the present invention to drive the scanning device 207 to move in three dimensions of the X-axis, Y-axis, and Z-axis, thereby performing an all-round scan of the front, back, left, right, and top surfaces of the ceramic shell 4 to be dried, and performing a lateral scan of the bottom to obtain an image of the main structure of the ceramic shell 4 to be dried, thereby more accurately determining the position and orientation of the deep holes in the ceramic shell 4 to be dried.

[0226] The present invention exemplarily provides a model structure analysis method, which specifically includes image analysis:

[0227] First, the outer contour model data, deep hole position data, and deep hole depth data of the ceramic shell 4 to be dried are obtained.

[0228] Then, the acquired image data is compared with the outer contour model data to determine the spatial orientation of the ceramic shell 4 to be dried currently hung in the vacuum drying chamber 1 .

[0229] Finally, the current deep hole position and orientation of the ceramic shell 4 to be dried are determined according to the spatial orientation of the ceramic shell 4 to be dried, and the deep hole position, orientation and depth data corresponding to the deep hole of the ceramic shell 4 to be dried are output.

[0230] Due to the rapid development of digital technology in recent years, it has become possible to design the ceramic shell to be dried by digital modeling. The ceramic shell to be dried obtained by digital model design has detailed various structural data. Therefore, the present invention compares the image data of the ceramic shell to be dried in an actual environment with the digital model, thereby quickly determining the position and orientation of the deep hole of the ceramic shell through the image data of the ceramic shell to be dried, and then obtaining the depth of the corresponding deep hole from the digital model, so as to obtain the position, orientation and depth data of the deep hole of the ceramic shell 4 to be dried.

[0231] The present invention exemplarily provides a scanning device 207, as shown in FIG6, the scanning device 207 further includes a scanning distance measuring device 2073. The scanning distance measuring device 2073 is used to measure the distance between the ceramic shell 4 to be dried and the scanning device 207 in real time.

[0232] The present invention exemplarily provides a model structure analysis method, comprising:

[0233] Step 1.1 The scanning distance measuring device 2073 performs a full-scale scan of the surface n of the ceramic shell 4 to be dried according to a preset route, and obtains a distance measurement data set G of all scanning points on the surface n relative to the scanning distance measuring device 2073. n .

[0234] Step 1.2 The ranging data set G n The end points are connected to obtain the digital surface m of the surface n of the ceramic shell 4 to be dried.

[0235] Step 1.3: Graphically analyze the digital surface m of the ceramic shell 4 to be dried in combination with the image data to determine the basic surface, convex surface, and concave surface of the digital surface m.

[0236] Step 1.4 Calculate the difference C between each distance measurement point on the groove surface and each distance measurement point on the adjacent basic surface of the groove mk-b , where mk is the groove numbered k on the digital surface m, and b is the separate number of the distance measurement point in the groove mk.

[0237] Step 1.5 Take C mk-b >K2 is a deep hole, take C mk-b >K3 is a through hole, wherein K2 is a preset deep hole judgment threshold, and K3 is a model width, model length, or model height corresponding to the surface n of the ceramic shell 4 to be dried.

[0238] Step 1.6 Count the positions W of all deep holes on the digital surface m of the ceramic shell to be dried mc The depth H corresponding to each deep hole mc , where c is the natural number of the deep hole on the digital surface m.

[0239] Step 1.7 Repeat steps 1.1 to 1.6 until all the deep holes on the surface of the ceramic shell 4 to be dried can be scanned. mc , depth H mc Statistics are completed, and the deep hole direction X is determined based on the surface n where the deep hole is located mc .

[0240] Step 1.8 Output the position W of all deep holes on the surface of the ceramic shell 4 to be dried mc , depth H mc , towards X mc data.

[0241] The present invention illustratively provides a method for obtaining the base surface, the convex surface, and the concave surface in step 1.3, comprising:

[0242] Step 1.3.1: Obtain image data corresponding to the digital surface m of the ceramic shell 4 to be dried, and obtain an image surface R by splicing the image data.

[0243] Step 1.3.2 performs element recognition on the image surface R to obtain element regions rn-m on the image surface R, where rn is the sequential number of the element regions in the digital surface m.

[0244] Step 1.3.3: Adjust the digital surface m to have the same orientation and similar size as the image surface R.

[0245] In step 1.3.4, the element region rc-m with the largest continuous area is taken as the base surface, and the rc-m belongs to rn-m.

[0246] Step 1.3.5 obtains the distance measurement point data of each non-basic surface feature area, where the feature area distance measurement points that are greater than the distance to the adjacent basic surface distance measurement points are groove points, and the feature area distance measurement points that are less than the distance to the adjacent basic surface distance measurement points are convex points.

[0247] In step 1.3.6, the adjacent groove points and convex points are connected to form groove surfaces and convex surfaces based on the element area.

[0248] FIG7 shows a ceramic shell 4 to be dried having a deep hole 401. Taking the left-facing front view of n=1 among the six front views of the ceramic shell 4 to be dried as an example, the above method is specifically as follows:

[0249] Step 1.1 The scanning distance measuring device 2073 performs an omnidirectional scan on the surface n=1 of the ceramic shell 4 to be dried according to a preset route, and obtains a distance measurement data set G1 of all scanning points on the surface n=1 relative to the scanning distance measuring device 2073.

[0250] Step 1.2 is as shown in FIG8 , connecting the end points of the distance measurement data set G1 to obtain the digital surface m=1 of the surface n=1 of the ceramic shell 4 to be dried.

[0251] Step 1.3: Graphically analyze the digital surface m=1 of the ceramic shell 4 to be dried in combination with the image data to determine the basic surface, convex surface, and concave surface of the digital surface m=1.

[0252] Step 1.4 Calculate the difference C between each distance measurement point on the groove surface and each distance measurement point on the adjacent basic surface of the groove mk-b , where mk is the groove numbered k on the digital surface m, and b is the other number of the distance measurement point in the groove mk. Since there are two grooves k=1 and k=2 at the digital surface m=1, and the distance measurement points inside k=1 include 5 distance measurement points from b=8 to b=12, it is necessary to calculate C mk-b =C 11-8 =|(L 11-8 )-(L 11-13 )|,C mk-b =C 11-9 =|(L 11-9 )-(L 11-13 )|,C mk-b =C 11-10 =|(L 11-10 )-(L 11-13 )|,C mk-b =C 11-11 =|(L 11-11 )-(L 11-13 )|,C mk-b =C 11-12 =|(L 11-12 )-(L 11-13)|. k=2 internal ranging points include 4 ranging points from b=18 to b=21, so it is necessary to calculate C mk-b =C 11-18 =|(L 11-18 )-(L 11-13 )|,C mk-b =C 11-19 =|(L 11-19 )-(L 11-1 3)|,C mk-b =C 11-20 =|(L 11-20 )-(L 11-13 )|,C mk-b =C 11-21 =|(L 11-21 )-(L 11-13 )|.

[0253] Step 1.5 Take C mk-b >K2 is a deep hole, take C mk-b >K3 is a through hole. Among them, K2 is a preset deep hole judgment threshold, and K3 is the model width or model length or model height corresponding to the surface n of the ceramic shell 4 to be dried. For example, C mk-b =C 11-10 >K2, so the groove with k=1 at m=1 on the digital surface is a deep hole.

[0254] Step 1.6 Count the positions W of all deep holes on the digital surface m=1 of the ceramic shell 4 to be dried mc =W 11 The depth H corresponding to each deep hole mc =H 11 , where c=1 is the natural number of the deep hole on the digital surface m=1. mc =W 11 The position is the position corresponding to the distance measurement points 8 to 12, and the depth of the deep hole is H mc =H 11 C mk-b =C 11-10 The calculated value of .

[0255] Step 1.7 Repeat steps 1.1 to 1.6 until all the deep holes on the surface of the ceramic shell 4 to be dried can be scanned. mc , depth H mc Statistics are completed, and the deep hole direction X is determined based on the surface n where the deep hole is located mc .

[0256] Step 1.8 Output the position W of all deep holes on the surface of the ceramic shell 4 to be dried mc , depth H mc , towards X mc data.

[0257] The present invention illustratively provides a method for obtaining the base surface, the convex surface, and the concave surface in step 1.3, comprising:

[0258] Step 1.3.1: Obtain image data corresponding to the digital surface m of the ceramic shell 4 to be dried, and obtain an image surface R by splicing the image data.

[0259] Step 1.3.2 performs element recognition on the image surface R to obtain element regions rn-m on the image surface R, where rn is the sequential number of the element regions in the digital surface m.

[0260] Step 1.3.3: Adjust the digital surface m to have the same orientation and similar size as the image surface R.

[0261] In step 1.3.4, the element region rc-m with the largest continuous area is taken as the base surface, and the rc-m belongs to rn-m.

[0262] Step 1.3.5 obtains the distance measurement point data of each non-basic surface feature area, where the feature area distance measurement points that are greater than the distance to the adjacent basic surface distance measurement points are groove points, and the feature area distance measurement points that are less than the distance to the adjacent basic surface distance measurement points are convex points.

[0263] In step 1.3.6, the adjacent groove points and convex points are connected to form groove surfaces and convex surfaces based on the element area.

[0264] In the prior art, not all ceramic shells 4 to be dried are obtained using digital model design, or the digital models of the ceramic shells 4 to be dried obtained using digital model design are not compatible with the vacuum rapid drying system. In this case, the vacuum rapid drying system cannot use the digital model to determine whether the shadows in the image data are deep holes, nor can it determine the depth of the deep holes from the image data. Using the above method of the present invention, the positions of all deep holes on the surface of the ceramic shell 4 to be dried can be confirmed through automatic scanning and analysis. mc , depth H mc , towards X mc Thus, the vacuum rapid drying system can obtain the necessary position W of the deep holes on the surface of the ceramic shell 4 to be dried. mc , depth H mc , towards X mc Data is used for wind turbine control analysis.

[0265] The present invention illustratively provides an electrically controlled pan / tilt platform 206, as shown in FIG5 , comprising: a fixed platform 2061 secured to an electrically controlled telescopic device 205; and a rotating platform 2062 rotatably connected to the fixed platform 2061 and capable of rotating relative to the fixed platform 2061 along a vertical axis. The rotating platform 2062 is rotatably connected to the fixed end of a second electrically controlled telescopic device 2064 via a speed reducer 2063. The speed reducer 2063 controls the rotation of the second electrically controlled telescopic device 2064 along a horizontal axis. The telescopic end of the second electrically controlled telescopic device 2064 is secured to a scanning device 207.

[0266] It is difficult to scan the bottom of the ceramic shell 4 to be dried using a conventional pan-tilt platform. Therefore, the present invention improves the pan-tilt platform structure. On the one hand, the second electrically controlled telescopic device 2064 enables the scanning device 207 to scan the bottom of the ceramic shell 4 to be dried. On the other hand, the speed reducer 2063 can change the rotation direction of the scanning device 207, thereby adding a degree of freedom of the scanning movement, thereby enabling the scanning device 207 to adapt to scanning more complex ceramic shells 4 to be dried.

[0267] The present invention exemplarily provides a model structure analysis method, which, based on the above model structure analysis, further includes:

[0268] Step 2.1: According to the deep hole position, control the scanning distance measuring device 2073 to move to the deep hole position.

[0269] Step 2.2: Acquire multiple deep hole depth measurement data by adjusting the orientation of the scanning distance measuring device 2073 relative to the deep hole.

[0270] Step 2.3 Use the deepest depth measurement data to correct the original deep hole depth data H m-c , get the corrected data H m-c `.

[0271] When designing the ceramic shell 4 to be dried, the deep hole structure is generally designed on the axis of the model, so that the deep holes of the ceramic shell are distributed along the axis. In this way, during the scanning and ranging process, the ranging laser can penetrate deep into the deep hole, measure the distance data of the deep hole, and thus determine the depth of the deep hole. However, in actual operation, not all ceramic shell deep holes are designed along the axis, and not all ceramic shells to be dried are placed or hooked in the normal direction during drying. Therefore, the direction of the deep hole may deviate from the operating axis of the scanning device 207. In this case, the laser emitted by the scanning and ranging device 2073 cannot penetrate deep into the deep hole, and the measured deep hole depth will be erroneous, thereby affecting the accuracy of the fan unit control analysis, resulting in a large difference between the actual drying speed of the deep hole portion of the ceramic shell 4 to be dried and the designed drying speed, affecting the uniformity of drying of various parts of the ceramic shell 4 to be dried.

[0272] By adopting the model structure analysis method supplemented by the present invention, at the deep hole position, by adjusting the orientation of the scanning ranging device 2073 relative to the deep hole, the scanning ranging device 2073 can obtain multiple ranging data in different orientations relative to the deep hole, including ranging data of ranging points where the orientation of the scanning ranging device 2073 is consistent with or similar to the axis of the deep hole. The ranging data is consistent with or highly similar to the depth of the deep hole, which can significantly improve the accuracy of the fan group control analysis, and significantly reduce the difference between the actual drying speed of the deep hole portion of the ceramic shell 4 to be dried and the designed drying speed.

[0273] The present invention illustratively provides a scanning device 207, as shown in FIG6 , which, in addition to the aforementioned scanning device 207, further includes an infrared temperature measuring device 2074. The control system includes a drying process analysis module that obtains the measurement data from the infrared temperature measuring device 2074 to analyze the drying process and determine whether the ceramic shell 4 to be dried is completely dried.

[0274] The present invention exemplarily provides a drying process analysis method, comprising: regularly or continuously measuring the temperature T inside the deep hole. v - Curve Q of drying time t v , when Q v When all curve segments that conform to the preset curve rule appear, it indicates that the drying of the ceramic shell 4 to be dried is completed. Wherein v is the natural number of all the deep holes in the ceramic shell 4 to be dried.

[0275] The present invention exemplarily provides a preset curve pattern, as shown in Figure 9, including: the temperature T inside the deep hole gradually decreases from the initial drying temperature T1 to the temperature T2 over the drying time, and then gradually increases to the drying environment temperature T3 over the drying time. When the deep hole temperature T of the ceramic shell 4 to be dried undergoes the process of T1-T2-T3 and maintains the drying environment temperature T3 for a preset time U, it is determined that the drying is complete. The initial drying temperature T1 is 22-26°C, the temperature T2 is 5-7°C lower than the temperature T1, and the drying environment temperature T3 is 24±1°C.

[0276] Conventional methods for determining the drying completion of the ceramic shells 4 rely primarily on experience or multiple tests to determine the appropriate drying time under specific drying conditions. Drying is considered complete when the drying time is reached. However, when this method is applied to multiple batches of ceramic shells 4, the drying time must be adjusted accordingly due to the inconsistent structures of each batch. This necessitates pre-testing the drying time, which significantly impacts overall drying efficiency.

[0277] After research, the applicant discovered that during the drying process of the ceramic shell 4, water volatilization is an endothermic process. Due to the high water content in the ceramic shell slurry during the initial drying phase, a large amount of water evaporates, causing the shell temperature to drop significantly. After the water evaporates to a certain extent, the water content in the ceramic shell slurry decreases, and the rate of water volatilization decreases, causing the shell temperature to gradually approach the drying ambient temperature. When the shell temperature remains at the drying ambient temperature, it indicates that almost no water has evaporated, indicating that drying is complete. Therefore, the method of determining the drying completion of the ceramic shell 4 according to the present invention determines whether the drying of the ceramic shell 4 is complete based solely on the temperature change curve during the drying process, and is not related to the structure of the ceramic shell 4. Therefore, each batch of ceramic shells 4 can be precisely dried, effectively overcoming the problems of existing drying time control methods.

[0278] At the same time, the applicant has conducted research and found that during the drying process, the temperature of the ceramic shell slurry will decrease as the water evaporates. On the other hand, the evaporation of water will also cause the ceramic shell to shrink to a certain extent (even with sand support). At this time, in the early stage of the ceramic shell drying, the wax mold will also cool down and shrink due to the cooling of the ceramic shell. Therefore, the ceramic shell will adhere to the surface of the shrunken wax mold during the drying process. When the ceramic shell begins to warm up, the wax mold will also expand as the temperature rises. However, the shrinkage and expansion process of the wax mold due to the influence of temperature is slower than the changes in the ceramic shell. Therefore:

[0279] If the ceramic shell cools down for too long—that is, the cooling amplitude is small and the drying time is too long—the wax mold will completely shrink under the prolonged low temperature. This, on the one hand, causes the ceramic shell to adhere to the significantly shrunken wax mold, resulting in significant spatial deformation of the resulting ceramic shell casting, affecting casting accuracy. On the other hand, when the wax mold warms up and expands, the large contraction-expansion ratio can easily break the solidified ceramic shell that adheres to the shrunken wax mold surface, leading to ceramic shell preparation failure or irregular protrusions on the casting surface, affecting casting accuracy. Excessive drying time also affects ceramic shell preparation efficiency.

[0280] If the cooling time of the ceramic shell is too short, that is, the cooling amplitude is too large and the drying time is too short, the deep holes will not be completely dried while the surface is already over-dried. That is, the window period for adjusting the drying time is very short, which is not conducive to adjusting the drying time of each part of the ceramic shell 4 to be dried, and increases the difficulty of controlling the drying uniformity of the ceramic shell 4 to be dried.

[0281] Thin-slurry ceramic shells have a low slurry concentration and a high moisture content, resulting in less slurry being able to be hung when slurry is applied. Therefore, the thickness of each layer of the ceramic shell is small and the thermal conductivity is good. This makes thin-slurry ceramic shells prone to various adverse problems caused by the above-mentioned long or short cooling time of the ceramic shell. Therefore, the control accuracy requirements of the drying process are too high and it is difficult to achieve.

[0282] Compared to thin-slurry shells, thick-slurry shells have a higher slurry concentration and lower moisture content. Therefore, more slurry can be applied during slurry application, resulting in a thicker layer and poorer thermal conductivity. Under the specified T2 temperature, which is 5-7°C lower than T1, the shell can be dried at a more suitable drying speed. This allows for efficient drying while preventing individual shell parts from drying too quickly, making it difficult to adjust the drying progress. Furthermore, drying can be completed before the wax pattern has fully contracted, allowing both the wax pattern and the shell to return to room temperature. This prevents the wax pattern from expanding and cracking the shell.

[0283] The present invention provides an exemplary method for determining whether a plurality of ceramic shells 4 to be dried are dried, comprising: detecting the temperature of each deep hole of each ceramic shell 4 to be dried one by one, and determining that the drying of the entire batch of ceramic shells 4 to be dried is completed when more than L% of the ceramic shells 4 to be dried are dried. The L%=(L g-d ) / (L 0-d )*100%, where L g-d is the number of ceramic shells 4 to be dried after drying in batch d, L 0-d is the number of all the ceramic shells 4 to be dried in batch d. The value of L% is: 100% ≥ L% ≥ E%. Where E is the preset threshold value of the minimum drying completion percentage of all the ceramic shells 4 to be dried in batch d.

[0284] In order to improve the drying efficiency of the ceramic shells, multiple ceramic shells 4 of the same structure are often dried simultaneously during a batch drying process. Due to the different placement or hooking methods of the multiple ceramic shells 4, the wind exposure of each ceramic shell 4 varies, and the drying time will vary. Therefore, a certain margin control is required. After the majority of the ceramic shells 4 are dried, the vacuum rapid drying is stopped to avoid the problem of overdrying the majority of the ceramic shells 4 after waiting for the ceramic shells with less wind to dry. The preset percentage threshold is determined based on the wind exposure differences of the ceramic shells 4 to be dried, and is generally not less than 98%. In this way, after the drying is completed, even if there are ceramic shells 4 that are not completely dried, their moisture content will not be too high, and drying can continue in the subsequent drying process to achieve complete drying.

[0285] The present invention exemplarily provides a fan group control analysis method A, comprising:

[0286] For all fan units p with deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0287] Step 3.1 Obtain the total number of deep holes D0 of the ceramic shell 4 to be dried, and obtain the total number of deep holes D0 of the surface of the ceramic shell 4 to be dried facing the fan group p. p The p is the number of the fan units arranged on different sides of the vacuum drying chamber 1.

[0288] Step 3.2 Calculate k S-p % = D p / D0*100%, the k S-p % is the control parameter of fan group p.

[0289] Step 3.3 Repeat steps 3.1 to 3.2 to obtain k for all fan groups S-p %.

[0290] For all fan units P that do not have deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0291] Calculate k F-p % = [1-D0 / (D0+1)] * 100%, the k F-p % is the control parameter of fan group p.

[0292] The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F- p% to run.

[0293] For example, the total number of deep holes on the ceramic shell 4 to be dried is D0=4, the total number of deep holes on the surface of the ceramic shell 4 to be dried facing the fan group p=1 is D1=1, the total number of deep holes on the surface of the ceramic shell 4 to be dried facing the fan group p=2 is D2=1, the total number of deep holes on the surface of the ceramic shell 4 to be dried facing the fan group p=3 is D3=2, and the remaining ceramic shells 4 to be dried have no deep holes and are provided with corresponding fan groups p=4, p=5, and p=6.

[0294] At this time, we can calculate: k S-1 %=D1 / D0*100%=(1 / 4)*100%=25%. k S-2 %=D2 / D0*100%=(1 / 4)*100%=25%. k S-3 %=D3 / D0*100%=(2 / 4)*100%=50%. k F-4 % = k F-5 % = k F-6 %=[1-D0 / (D0+1)]*100%=(1-4 / 5)*100%=20%.

[0295] Using the fan group control and analysis method of this example of the present invention, the operating conditions of each fan group can be automatically and adaptively adjusted based on the acquired distribution of deep holes in the ceramic shell 4 to be dried. This ensures that the portion of the ceramic shell 4 to be dried with more deep holes receives more air, resulting in a faster drying speed, which facilitates rapid drying within the deep holes. Meanwhile, portions with fewer or no deep holes receive less air, resulting in a slower drying speed, which facilitates synchronization with the drying time of the deep holes. This ensures that all portions of the ceramic shell 4 to be dried have a consistent drying degree, while also achieving complete drying in a shorter drying time.

[0296] Moreover, this method is only related to the number and position of the deep holes of the ceramic shell 4 to be dried. For various types of structures, such as standard or non-standard structures of the ceramic shell 4 to be dried, better drying control with shorter drying time and uniform drying time for each part of the ceramic shell can be achieved.

[0297] The present invention exemplarily provides a fan group control analysis method B, comprising:

[0298] For all fan units p with deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0299] Step 4.1 Obtain the total number of deep holes D0 of the ceramic shell 4 to be dried, and obtain the total number of deep holes D0 on the surface of the ceramic shell 4 to be dried facing the fan group p. p The p is the number of the fan units arranged on different sides of the vacuum drying chamber 1.

[0300] Step 4.2 According to D0 and D p The number of k is obtained from the control parameter database S-p %. The k S-p % is the control parameter of fan group p.

[0301] Step 4.3 Repeat steps 4.1 to 4.2 to obtain the k of all fan groups. S-p %.

[0302] For all fan units P that do not have deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0303] According to the total number of deep holes D0 of the ceramic shell 4 to be dried, k is obtained from the control parameter database. F-p %. The k F-p % is the control parameter of fan group p.

[0304] The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

[0305] The present invention exemplarily provides a method for entering k into a control parameter database. S-p % and k F-p % of methods include:

[0306] Step 5.1: Simulate the same position and orientation of the fan unit as that of the target vacuum drying chamber 1 in the simulation device.

[0307] Step 5.2 Preset the deep hole distribution of different ceramic shells 4 to be dried for drying training, and determine the control parameter k of each fan group p relative to full load corresponding to the optimal drying time under each deep hole distribution condition. S-p % and k F-p %; the deep hole distribution includes: deep hole direction and number; the optimal drying time is the shortest time for the deep holes and the surface of the ceramic shell 4 to be dried to complete the synchronous drying;

[0308] Step 5.3 Repeat step 5.2 until the deep hole distribution under normal conditions is trained and D0-D p —k S-p %—k F-p % of the deep hole-control parameter relationship group and store it in the control parameter database.

[0309] By using the fan group control analysis method of this example of the present invention, a large number of deep hole-control parameter relationship groups with relatively comprehensive optimal conditions can be prepared in the vacuum drying system database through preliminary experiments. In this way, when the total number of deep holes D0 of the ceramic shell 4 to be dried is obtained, the total number of deep holes D0 on the surface of the ceramic shell 4 to be dried facing the fan group p is obtained. p After that, the deep hole-control parameter relationship group pre-stored in the control parameter database can be used to theoretically match the D0-D p Related best k S-p % and k F-p %Control the corresponding fan group.

[0310] Since the best result of the experiment is: p Under the deep hole relationship group, k S-p %—k F-pThe control parameters of % can be used to control the operation of the fan unit, which can ensure that the drying degree of each part of the ceramic shell 4 to be dried tends to be consistent, and the drying time is minimized. The drying time is closely related to the volume, surface area, and surface structure of the ceramic shell 4 to be dried. Therefore, this method needs to be judged together with the digital model structure of the ceramic shell 4 to be dried. The standard ceramic shell 4 to be dried is a commonly used component and can be simulated in advance. The non-standard ceramic shell 4 to be dried is a special-shaped part designed according to needs, and its structure is diverse. Pre-tests may not cover it. The control parameter database lacks the D0-D corresponding to the special-shaped ceramic shell 4 to be dried. p —k S-p %—k F-p % deep hole - control parameter relationship group, the fan group control analysis method B in the example cannot obtain the required D0-D p —k S-p %—k F-p % of the deep hole - control parameter relationship group, at this time, the fan group control analysis method A provided in the example should be used to analyze and obtain the D0-D corresponding to the special-shaped ceramic shell 4 to be dried p —k S-p %—k F-p % of deep hole-control parameter relationship group.

[0311] The fan group control analysis method B of the example and the fan group control analysis method A of the example can be used separately or in combination.

[0312] The present invention exemplarily provides a fan group, wherein at least two fans are arranged in an array, and the fan group control module synchronously controls or individually controls the fans in each fan group.

[0313] The present invention exemplarily provides a wind turbine group control analysis method C based on a wind turbine group having at least two wind turbines. The method, based on the above-mentioned wind turbine group control analysis method A or wind turbine group control analysis method B, further includes:

[0314] Step 6.1 constructs a three-dimensional coordinate system based on the scanning starting point preset by the scanning device 207.

[0315] Step 6.2: The scanning device 207 records the three-dimensional coordinate points in the process of displacement, and in the process of model structure analysis, the deep hole position, direction and depth of the ceramic shell 4 to be dried are marked with three-dimensional coordinate points.

[0316] Step 6.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p.

[0317] Step 6.4 Count U p-eNumber of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up .

[0318] Step 6.5 Calculate k up-e %=(D up-e / D up )*k S-p %.

[0319] The fan group control module obtains the k of each fan in the fan group p. up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % Run. For D up-e =0, the fan operates at the lowest power.

[0320] For example, fan group p contains two fans, numbered p-1 and p-2. Since the fans are fixed relative to the preset scanning starting point of the scanning device 207, the coordinate positions of fans p-1 and p-2 in the three-dimensional coordinate system constructed in step 6.1 are also fixed. At this time, fan p-1 can form a cylindrical air duct p-1 with a diameter of R = 100 cm in the three-dimensional coordinate system with the fan shaft axis as the central axis. The intersection of the cylindrical air duct p-1 and the corresponding surface of the ceramic shell 4 to be dried is the coordinate system range U covered by fan p-1. p-1 Statistics U p-1 The number of deep holes D up-1 , for example D up-1 =1, D up-2 =2, and the number of deep holes D within the overall coverage of the fan group p up , for example D up =3. From this we can calculate: k up-1 %=(D up-1 / D up )*k S-p % = (1 / 3) * k S-p %.k up-2 %=(D up-2 / D up )*k S-p % = (2 / 3) * k S-p %.

[0321] That is, in fan group p, fan 1 has (1 / 3)*k S-p % of the state, fan 2 operates at (2 / 3)*k S-p % Status Running.

[0322] Using the fan group control analysis method C of the present invention, individual control parameters for each fan within fan group P can be calculated, thereby enabling independent control of multiple fans within fan group P. This method can make the air blown by fan group P toward the ceramic shell 4 to be dried more targeted, resulting in more consistent drying completion times for various parts of the ceramic shell 4 to be dried, particularly those with deep holes and those without deep holes.

[0323] The present invention exemplarily provides a wind turbine group control analysis method D based on a wind turbine group having at least two wind turbines. The method, based on the above-mentioned wind turbine group control analysis method A or wind turbine group control analysis method B, further includes:

[0324] Step 7.1 constructs a three-dimensional coordinate system based on the scanning starting point preset by the scanning device 207.

[0325] Step 7.2: The scanning device 207 records the three-dimensional coordinate points in the process of displacement, and in the process of model structure analysis, the deep hole position, direction and depth of the ceramic shell 4 to be dried are marked with three-dimensional coordinate points.

[0326] Step 7.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p.

[0327] Step 7.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up .

[0328] Step 7.5 According to D up and D up-e Get the k value of the corresponding fan from the control parameter database up-e %, the k up-e % is the control parameter of the fan numbered e in the fan group p.

[0329] The fan group control module obtains the k of each fan in the fan group p. up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % to run.

[0330] The present invention provides an exemplary method for entering k into a control parameter database. up-e % methods, specifically including:

[0331] Step 8.1: Simulate the same position and orientation of the fan unit as that of the target vacuum drying chamber 1 in the simulation device.

[0332] Step 8.2 Preset the deep hole distribution of different ceramic shells 4 to be dried for drying training, and determine the operation ratio k of each fan in each fan group p when the fan is relatively fully loaded corresponding to the optimal drying time under each deep hole distribution condition. up-e The deep hole distribution includes the direction and number of the deep holes. The optimal drying time is the shortest time for the deep holes and the surface layer of the ceramic shell 4 to be dried to be synchronously dried.

[0333] Step 8.3 Repeat step 8.2 until the deep hole distribution under normal conditions is trained and D up —D up-e —k up-e % of the deep hole-control parameter relationship group and store it in the control parameter database.

[0334] By using the fan unit control analysis method of this example of the present invention, a large number of D values ​​under the optimal conditions with relatively comprehensive conditions can be prepared in the database of the vacuum drying system through preliminary experiments. up —D up-e —k up-e % deep hole-control parameter relationship group. In this way, when determining the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e and U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up When the D up —D up-e —k up-e % of the deep hole - control parameter relationship group, theoretically with D up —D up-e Related best k up-e % Control each fan individually based on the corresponding fan control parameters.

[0335] Similar to the example of fan group control analysis method B, the example of fan group control analysis method D is mainly applicable to the ceramic shell 4 to be dried with the model structure covered by the pre-simulation experiment. For the ceramic shell 4 to be dried with the model structure not covered by the pre-simulation experiment, the example of fan group control analysis method C is used to obtain D. up —D up-e —k up-e % of deep hole-control parameter relationship group.

[0336] The present invention exemplarily provides a vacuum rapid drying system, comprising: a first data transmission module, a local database module and a remote system module.

[0337] The first data transmission module is signal-connected to the remote system module via a signal line connection or a wireless network connection.

[0338] The local database module is used as a control parameter database to store relevant deep hole-control parameter relationship groups and operation result data.

[0339] The remote system module collects the deep hole-control parameter relationship groups and operation result data of each vacuum rapid drying system through the first data transmission module, and selects the deep hole-control parameter relationship group corresponding to the best operation result from the same deep hole relationship. Based on authorization permission and / or instructions and / or automatic synchronization, the deep hole-control parameter relationship group corresponding to the best operation result is centralized through the remote system module and then synchronized to the local database module of each vacuum rapid drying system through the first data transmission module, or directly synchronized to the local database module of each vacuum rapid drying system through the first data transmission module.

[0340] When the vacuum rapid drying system calls the deep hole-control parameter relationship group in the local database module, if a new optimal deep hole-control parameter relationship group exists, the new optimal deep hole-control parameter relationship group is called first.

[0341] For example: Each vacuum rapid drying system is connected to the remote system module through the Internet. At this time, the local database module of each vacuum rapid drying system records the D of model A. up —D up-e —k up-e The best result corresponding to the deep hole-control parameter relationship group is B; at this time, a company or equipment manufacturer, through experiments or accidental discovery, changes D up —D up-e —k up-e % The control parameters in the deep hole-control parameter relationship group are adjusted to k up-e %`, we can get a better result C than the best result B. At this time, the new D recorded for model A up —D up-e —k up-e The %`deep hole-control parameter relationship group and the corresponding optimal result C are centrally collected through the remote system module of the present invention, and then synchronized to the local database module of each vacuum rapid drying system through the first data transmission module, or directly synchronized to the local database module of each vacuum rapid drying system through the first data transmission module.

[0342] Through the data synchronization method of the present invention, the optimal control parameters for a certain model obtained by a certain enterprise or equipment manufacturer can be synchronized to all other networked vacuum rapid drying systems to improve the control parameters for the model in D up —D up-eThe control parameters under the conditions are optimized to improve the drying efficiency. Therefore, the present invention can continuously optimize and improve the control parameters of the fan group and each fan in the fan group during actual operation, thereby improving the overall drying efficiency and increasing the benefits to the enterprise.

[0343] The present invention exemplarily provides a vacuum rapid drying system, comprising: a second data transmission module and a remote system module.

[0344] The remote system module is connected to the control system signal of the vacuum rapid drying system through a second data transmission module in the form of a signal line connection or a wireless network connection, so as to send remote control instructions to the control system and / or obtain control instructions issued by the control system and / or obtain operating status parameters of various electronic control devices in the vacuum rapid drying system.

[0345] The execution priority of the remote control instruction issued by the remote system module is higher than the execution priority of the control instruction issued by the control system.

[0346] The vacuum rapid drying system in this example can be operated with the intervention of a remote system module, enabling remote control of the vacuum rapid drying system. This exemplary approach can facilitate remote control and self-testing of equipment for users, improving the efficiency of early equipment adjustments and subsequent equipment maintenance.

[0347] The present invention illustratively provides a drying rack 3, comprising a ceramic shell hanger 304 for hanging ceramic shells 4 to be dried. The ceramic shell hanger 304 is provided with a plurality of hooking slots 305. The ceramic shells 4 to be dried are hooked into the hooking slots 305 via hooks 11. A hanger support plate 302 is fixed to the bottom of the ceramic shell hanger 304. The bottom of the hanger support plate 302 is provided with a plurality of rollers 303 that can slide along a guide rail 301. The guide rail 301 is fixed to the bottom surface of the vacuum drying chamber 1.

[0348] Because the ceramic shell preparation process involves multiple sizing and corresponding drying operations, a convenient, removable fixing method is required between the ceramic shell to be dried 4, the ceramic shell hanger 304, and the vacuum drying chamber 1. The present invention provides a removable fixing method between the ceramic shell to be dried 4, the ceramic shell hanger 304, and the vacuum drying chamber 1. Specifically, the ceramic shell to be dried 4 can be hooked in the hooking groove 305 via the hook 11, so that the ceramic shell to be dried 4 and the ceramic shell hanger 304 can be conveniently hooked / removed and removably fixed. The ceramic shell hanger 304 is then slid into / out of the guide rail 301 to achieve convenient, removable fixing between the ceramic shell to be dried 4 and the vacuum drying chamber 1.

[0349] The present invention illustratively provides a guide rail 301 with a stopper on the side away from the door of the vacuum drying chamber 1. As shown in Figure 1, the stopper is located on the side of the guide rail 301 near the adjustable member 108. This arrangement ensures that the ceramic shell hanger 304 remains relatively fixed when it is slid into the vacuum drying chamber 1. This ensures that the fan assembly faces a similar number of ceramic shells 4 during each drying process, improving drying stability.

[0350] The present invention exemplarily provides a scanning device 207, which includes a thermal imager 2072. The method for making the drying time of each part of the ceramic shell to be dried tend to be consistent includes:

[0351] Step 9.1: During the drying process of the ceramic shell 4 to be dried, the thermal imager 2072 and the scanning device 207 take real-time thermal imaging photos of the ceramic shell 4 to be dried, and send the photos to the control system.

[0352] Step 9.2: The control system determines, based on the heat distribution in the thermal imaging image, whether there is an area T with a high / low temperature difference exceeding a preset temperature difference threshold when the drying time exceeds the preset first drying time. If there is an area T, the control system performs the following determination and operation:

[0353] When the temperature of the low-temperature area of ​​region T is lower than the preset low-temperature threshold, the operating power of the fan group corresponding to region T is reduced.

[0354] When the temperature of the high temperature area of ​​region T is higher than the preset high temperature threshold, the operating power of the fan group corresponding to region T is increased.

[0355] When the existence time of area T exceeds the preset time threshold, and the temperature of the low temperature area of ​​area T is higher than the preset low temperature threshold, and the temperature of the high temperature area of ​​area T is lower than the preset high temperature threshold, the operating power of the fan group corresponding to area T is increased.

[0356] The present invention exemplarily provides a preset low temperature threshold of 12-15°C.

[0357] The present invention exemplarily provides a preset high temperature threshold of 26-28°C.

[0358] The present invention exemplarily provides a preset first drying time of 1-3 minutes.

[0359] The present invention exemplarily provides a preset time threshold of 30-60 seconds.

[0360] One of the main problems to be solved by the present invention is to achieve a uniform drying degree for each part of the ceramic shell 4 to be dried, and to achieve a uniform drying time for each part of the ceramic shell 4 to be dried. Using the method of achieving a uniform drying time for each part of the ceramic shell to be dried as exemplified in the present invention, the control parameters of each fan unit can be dynamically adjusted during the drying process based on the temperature changes of each part in the thermal image of the ceramic shell 4 to be dried, so that the drying time of each part of the ceramic shell 4 to be dried is more uniform during the drying process.

[0361] The present invention illustratively provides a method for rapid vacuum drying, comprising:

[0362] When drying the surface layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 750-720 mmHg within 5 seconds. Then, restore the vacuum level from 750-720 mmHg to atmospheric pressure within 5 seconds. Repeat this process until the surface layer is completely dried.

[0363] When drying the transition layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 720-680 mmHg within 7 seconds. Then, restore the vacuum level from 720-680 mmHg to atmospheric pressure within 7 seconds. Repeat this process until the transition layer is completely dried.

[0364] When drying the support layer, the following steps are included:

[0365] Step 10.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-20 mmHg within 30 seconds.

[0366] Step 10.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0367] Step 10.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds.

[0368] Step 10.4: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-20 mmHg within 30 seconds.

[0369] In step 10.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds.

[0370] Step 10.6 Repeat steps 10.4 and 10.5 until the support layer is completely dry.

[0371] When drying the sealing layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 120-90 mmHg within 40 seconds. Then, return the vacuum level of the ceramic shell to atmospheric pressure within 120 seconds. Repeat this process until the sealing layer is completely dried.

[0372] The existing vacuum rapid drying technology for ceramic shells is mainly based on thin slurry ceramic shells. Through the reciprocating operation of vacuuming and re-pressing, the surface layer and transition layer can be dried quickly. The support layer can expand under the reciprocating high negative pressure conditions to form a sponge-like structure, increasing the thickness of the ceramic shell while reducing the breaking strength coefficient of the ceramic shell.

[0373] Compared with the existing vacuum rapid drying technology for thin slurry ceramic shells, thick slurry ceramic shells have a lower moisture content and should theoretically be able to achieve rapid drying under simpler control conditions. For example, the vacuum rapid drying method for thin slurry ceramic shells disclosed in CN 201610416881.4: "When drying the support layer of the ceramic shell, first, within 60 seconds, the sealed cavity is evacuated to a vacuum state of 300-100 mm of mercury column, maintained for 400-600 seconds, and then the sealed cavity is vacuum deflated to return the sealed cavity to normal pressure; then step b is started, in which the sealed cavity is evacuated to a vacuum state of 300-100 mm of mercury column within 60 seconds, and then the sealed cavity is vacuum deflated to return the sealed cavity to normal pressure; then step b is started, in which the sealed cavity is evacuated to a vacuum state of 300-100 mm of mercury column within 60 seconds, and then the sealed cavity is vacuum deflated to return the sealed cavity to normal pressure; then the sealed cavity is vacuum deflated ... Step c is then performed; in step c, the sealed cavity is vacuum-deflated within 120 seconds to return the sealed cavity to atmospheric pressure, and then step b is restarted; the support layer of the resulting ceramic shell exhibits a sponge-like, loose structure. According to common knowledge, when drying the support layer of a thick slurry ceramic shell, rapid drying can be achieved under simpler control conditions. For example, a slower decompression period of 90 seconds can be employed to reduce the sealed cavity to a vacuum of 500-400 mmHg. However, in reality, the applicant's research has revealed that vacuum drying conditions for optimally dried thick slurry ceramic shells are more challenging than those for thin slurry ceramic shells. For example, when drying the support layer of a thick slurry ceramic shell, the vacuum level of the ceramic shell to be dried must be reduced from atmospheric pressure to 260-20 mmHg within 30 seconds, and then restored to atmospheric pressure within 90 seconds. This is because the concentrated slurry shell contains less moisture than the sand or granular materials, which in turn contain a higher content. This easily hinders the flow of moisture and airflow within the shell, leading to the shell's surface drying out while the internal moisture remains unevaporated during the drying process. Therefore, in a theoretically low controlled environment, the water volatilization efficiency within the concentrated slurry shell differs significantly from the theoretical efficiency. This requires a lower negative pressure environment and a faster depressurization rate to allow the water and bubbles within the concentrated slurry shell to form an effective flow. This allows for the formation of a uniformly distributed sponge-like structure caused by the bubble flow and expansion of the shell layer during the drying process. Furthermore, this allows for the effective discharge of moisture from the concentrated slurry shell, ultimately achieving truly rapid drying.

[0374] The present invention exemplarily provides a method for drying a support layer, wherein the support layer is provided with at least three layers in sequence from a transition layer to a sealing layer, wherein:

[0375] The inner surface of the first support layer is bonded to the outer surface of the transition layer, and the vacuum rapid drying process of the first support layer is performed, including the following steps:

[0376] Step 11.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-220 mmHg within 30 seconds.

[0377] Step 11.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0378] In step 11.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0379] In step 11.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 260-220 mmHg within 30 seconds.

[0380] In step 11.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0381] Step 11.6 Repeat steps 11.4 and 11.5 until the first layer of the support layer is dry.

[0382] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0383] Step 12.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 200-150 mmHg within 30 seconds.

[0384] Step 12.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0385] In step 12.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0386] In step 12.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 200-150 mmHg within 30 seconds.

[0387] In step 12.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0388] Step 12.6 Repeat steps 12.4 and 12.5 until the second layer of support layer is dry.

[0389] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0390] Step 13.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0391] Step 13.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0392] Step 13.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds.

[0393] Step 13.4: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0394] In step 13.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds.

[0395] Step 13.6 Repeat steps 13.4 and 13.5 until the third support layer is dry.

[0396] The inner surface of the sealing layer is in contact with the outer surface of the third layer of the supporting layer.

[0397] The vacuum rapid drying method exemplified in the present invention can ensure that the thick slurry ceramic shell support layer has an optimal drying speed during the vacuum drying process, and on the other hand, the dried ceramic shell has a good breaking strength coefficient and can provide sufficient supporting force to meet the use requirements of precision casting.

[0398] The present invention illustratively provides a vacuum rapid drying system, as shown in Figure 1 , comprising: a vacuum drying chamber 1, a vacuum pump 8, and a control system. The vacuum pump 8 evacuates the vacuum drying chamber 1. The vacuum pump 8 is connected to the vacuum drying chamber 1 via a first connecting pipe, which is provided with a first electrically controlled on / off valve 10. An air pipe 106 is connected to the vacuum drying chamber 1, which is provided with a second electrically controlled valve 107.

[0399] The ceramic shell 4 to be dried is placed in the vacuum drying chamber 1 for vacuum rapid drying.

[0400] The control system controls the opening and closing of the vacuum pump 8, the first electrically controlled switch valve 10, and the second electrically controlled valve 107 to implement the method steps of the vacuum rapid drying process.

[0401] The vacuum rapid drying system further includes a vacuum tank 5. One end of the vacuum tank 5 is connected to a vacuum pump 8 via a second connecting pipe, which is provided with a third electrically controlled valve 9. The other end of the vacuum tank 5 is connected to the vacuum drying chamber 1 via a third connecting pipe 7, which is provided with a fourth electrically controlled valve 6.

[0402] The present invention exemplarily provides a method for reducing pressure during vacuum drying of a support layer and a sealing layer, which is an instantaneous pressure reduction operation. The instantaneous pressure reduction operation includes:

[0403] First, before reducing the pressure, the fourth electrically controlled valve 6 is closed, and the vacuum tank 5 is evacuated to a low vacuum state in advance.

[0404] Then, when the pressure is reduced, the fourth electrically controlled valve 6 is opened to connect the vacuum drying chamber 1 with the vacuum tank 5, and the pressure is instantly reduced to the equilibrium low pressure within 0.5 seconds.

[0405] Finally, the vacuum pump 8 simultaneously extracts the gaseous components in the vacuum tank 5 and the vacuum drying chamber 1, so that the vacuum degree in the vacuum drying chamber 1 meets the preset target, and then closes the fourth electrically controlled valve 6 and the first electrically controlled switch valve 10. At the same time, the vacuum pump 8 continues to extract the gaseous components in the vacuum tank 5 to the vacuum tank 5 to a low vacuum state.

[0406] The present invention exemplarily provides a vacuum rapid drying method for a support layer and a sealing layer combined with an instantaneous pressure reduction operation, wherein the support layer is provided with at least three layers in sequence from a transition layer to a sealing layer, wherein:

[0407] The inner surface of the first support layer is bonded to the outer surface of the transition layer, and the vacuum rapid drying process of the first support layer is performed, including the following steps:

[0408] Step 14.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank 5 maintains vacuum.

[0409] Step 14.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank 5.

[0410] In step 14.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank 5 continues to be evacuated.

[0411] Step 14.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank 5 maintains vacuum.

[0412] In step 14.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank 5 continues to be evacuated.

[0413] Step 14.6 Repeat steps 14.4 and 14.5 until the first layer of the support layer is dry.

[0414] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0415] Step 15.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank 5 maintains vacuum.

[0416] Step 15.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank 5.

[0417] In step 15.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank 5 continues to be evacuated.

[0418] Step 15.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank 5 maintains vacuum.

[0419] In step 15.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank 5 continues to be evacuated.

[0420] Step 15.6 Repeat steps 15.4 and 15.5 until the second layer of the support layer is dry.

[0421] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0422] Step 16.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank 5 maintains vacuum.

[0423] Step 16.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank 5.

[0424] In step 16.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank 5 continues to be evacuated.

[0425] Step 16.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank 5 maintains vacuum.

[0426] In step 16.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank 5 continues to be evacuated.

[0427] Step 16.6 Repeat steps 16.4 and 16.5 until the third layer of support layer is dry.

[0428] The inner surface of the sealing layer is attached to the outer surface of the third layer of the support layer, and the vacuum rapid drying process of the sealing layer is performed, which includes the following steps:

[0429] Step 17.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 35 seconds, while the vacuum tank 5 maintains vacuum.

[0430] In step 17.2, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 120 seconds, and the vacuum tank 5 continues to be evacuated.

[0431] Step 17.3 Repeat steps 17.1 and 17.2 until the sealing layer is completely dry.

[0432] The above-mentioned example technology is combined with a specific instantaneous pressure reduction operation, which can further shorten the drying time of the thick slurry shell film, further reduce the breaking strength coefficient, and further increase the average thickness of the ceramic shell support layer, thereby maintaining sufficient supporting force while making the thick slurry ceramic shell also have an excellent breaking strength coefficient, thereby improving the applicability of the thick slurry ceramic shell in precision casting.

[0433] In order to explain the technical solution of the present application in more detail, the technology of the present application is further specifically described below in combination with specific embodiments and comparative examples.

[0434] Slurry preparation:

[0435] (1) Concentrated slurry A: A slurry obtained by compounding slurry sol, powder, water, and sand, and meeting the following requirements: the concentration of each slurry layer is expressed by the Zahn cup method using a No. 4 Zahn measuring cup, wherein the concentration of the surface slurry is 58 seconds, the concentration of the transition layer slurry is 32 seconds, the concentration of the support layer slurry is 24 seconds, and the concentration of the sealing layer slurry is 11 seconds. The sealing layer does not contain sand. When covering the surface layer of the slurry to be dried with sand, 100 mesh sand is used, when covering the transition layer of the slurry to be dried with sand, 60 mesh sand is used, and when covering the support layer of the slurry to be dried with sand, 30 mesh sand is used. The slurry sol is silica sol, and the mass concentration of silicon dioxide is 25%. The powder is 300 mesh zirconium powder.

[0436] (2) Slurry: A slurry obtained by mixing slurry sol, powder, water, and sand, and meeting the following requirements: the concentration of each layer of slurry is expressed by the Zahn cup method using a No. 4 Zahn measuring cup, wherein the concentration of the surface layer slurry is 45 seconds, the concentration of the transition layer slurry is 26 seconds, the concentration of the support layer slurry is 14 seconds, and the concentration of the sealing layer slurry is 11 seconds. The sealing layer does not contain sand. When covering the surface layer of the slurry to be dried with sand, 100 mesh sand is used, when covering the transition layer of the slurry to be dried with sand, 60 mesh sand is used, and when covering the support layer of the slurry to be dried with sand, 30 mesh sand is used. The slurry sol is silica sol, and the mass concentration of silicon dioxide is 25%. The powder is 300 mesh zirconium powder.

[0437] Test method:

[0438] (1) Breaking strength coefficient:

[0439] Ceramic shells from the same batch were subjected to dewaxing and high-temperature treatment at 1050°C for 1.5 hours to obtain casting shells. The maximum pressure the shells withstand upon breaking was used as the breaking strength coefficient. The breaking strength coefficients of at least five shells from the same batch were averaged and used as the breaking strength coefficient for the Examples or Comparative Examples of the present invention.

[0440] (2) Ceramic shell thickness:

[0441] The same batch of ceramic shells were subjected to wax removal and high temperature treatment at 1050° C. for 1.5 hours to obtain casting ceramic shells. The average thickness of at least five of the ceramic shells at the casting port was taken as the thickness of the ceramic shell of the present invention, in cm.

[0442] (3) Drying time:

[0443] The drying time of the present invention is the average of the drying times of each layer of the ceramic shell 4 to be dried, from the surface layer to the sealing layer, and is expressed in minutes. The drying time of each layer is the time it takes for the corresponding layer of the ceramic shell 4 to be dried to be placed in the vacuum rapid drying system until the drying of that layer is completed.

[0444] (4) Drying yield rate:

[0445] Q% = (number of ceramic shells that have passed drying in this batch) / (total number of ceramic shells in this batch) * 100%, rounded to the nearest integer. The criteria for determining whether a ceramic shell has passed drying are: no overdrying of the ceramic shell after drying, and both the humidity in the deep holes and the humidity on the surface of the ceramic shell are less than 3%.

[0446] A ceramic shell preparation method 1, comprising:

[0447] S1. Apply a corresponding number of layers of ceramic shell slurry to the outside of the wax mold layer by layer, and obtain the corresponding layers of ceramic shell to be dried after each application of the ceramic shell slurry.

[0448] S2. Each corresponding layer of the ceramic shell to be dried is placed in a vacuum rapid drying system for vacuum rapid drying. After the drying of the ceramic shell of the layer is completed, the ceramic shell slurry of the next layer is applied.

[0449] During the vacuum rapid drying process, the model information of the ceramic shell to be dried is first obtained, and then the control parameters of the blowers on different sides of the ceramic shell to be dried are adjusted according to the model information, so that the drying time of each part of the ceramic shell to be dried tends to be consistent.

[0450] S3. After all layers of the ceramic shell are dried, the ceramic shell for precision casting is obtained.

[0451] The vacuum rapid drying system includes: a vacuum drying chamber 1, a vacuum pump 8, a control system, a first data transmission module, a second data transmission module, a local database module, and a remote system module. The vacuum pump 8 evacuates the vacuum drying chamber 1. The vacuum pump 8 is connected to the vacuum drying chamber 1 via a first connecting pipe, which is equipped with a first electrically controlled on / off valve 10. An air pipe 106 is connected to the vacuum drying chamber 1, which is equipped with a second electrically controlled valve 107.

[0452] The first data transmission module is signal-connected to the remote system module via a signal line connection or a wireless network connection.

[0453] The local database module is used as a control parameter database to store relevant deep hole-control parameter relationship groups and operation result data.

[0454] The remote system module collects the deep hole-control parameter relationship groups and operation result data of each vacuum rapid drying system through the first data transmission module, and selects the deep hole-control parameter relationship group corresponding to the best operation result from the same deep hole relationship. Based on authorization permission and / or instructions and / or automatic synchronization, the deep hole-control parameter relationship group corresponding to the best operation result is centralized through the remote system module and then synchronized to the local database module of each vacuum rapid drying system through the first data transmission module, or directly synchronized to the local database module of each vacuum rapid drying system through the first data transmission module.

[0455] When the vacuum rapid drying system calls the deep hole-control parameter relationship group in the local database module, if a new optimal deep hole-control parameter relationship group exists, the new optimal deep hole-control parameter relationship group is called first.

[0456] The remote system module is connected to the control system signal of the vacuum rapid drying system through a second data transmission module in the form of a signal line connection or a wireless network connection, so as to send remote control instructions to the control system and / or obtain control instructions issued by the control system and / or obtain operating status parameters of various electronic control devices in the vacuum rapid drying system.

[0457] The execution priority of the remote control instruction issued by the remote system module is higher than the execution priority of the control instruction issued by the control system.

[0458] A drying rack 3 is detachably mounted within the vacuum drying chamber 1, and the ceramic shell 4 to be dried is detachably mounted on the drying rack 3 for drying. A first blower unit 101 is provided at the top of the drying rack 3, a second blower unit 102 is provided at the bottom of the drying rack 3, a third blower unit 103 is provided on the opening and closing door of the vacuum drying chamber 1, and a fourth blower unit 104 and a fifth blower unit 105 are provided on either side of the drying rack 3 along the axial direction of the vacuum drying chamber 1. An adjustable component 108 is provided on the opposite side of the third blower unit 103. The adjustable component 108 is a sixth blower unit.

[0459] As shown in Figures 1-2, the drying rack 3 includes a ceramic shell hanger 304 for hanging the ceramic shells 4 to be dried. The ceramic shell hanger 304 is provided with a plurality of hooking slots 305. The ceramic shells 4 to be dried are hooked into the hooking slots 305 via hooks 11. A hanger support plate 302 is fixed to the bottom of the ceramic shell hanger 304. The bottom of the hanger support plate 302 is provided with a plurality of rollers 303 that can slide along a guide rail 301. The guide rail 301 is fixed to the bottom surface of the vacuum drying chamber 1.

[0460] The guide rail 301 is provided with a limit block on the side away from the opening and closing door of the vacuum drying chamber 1. As shown in FIG1 , the guide rail 301 is provided with a limit block on the side close to the adjustable component 108.

[0461] A three-dimensional detection mechanism 2 is provided within the vacuum drying chamber 1. As shown in Figures 1 to 4, the three-dimensional detection mechanism 2 comprises two parallel X-axis guide rails 201 arranged horizontally along the axial direction of the vacuum drying chamber 1 and located on either side of the drying rack 3, and a Y-axis guide rail 202 arranged horizontally along the transverse direction of the vacuum drying chamber 1. Each of the two X-axis guide rails 201 is provided with a first displacement device 203 capable of displacement along the X-axis guide rail 201. The Y-axis guide rail 202 is secured between the two first displacement devices 203 and is driven by the two first displacement devices 203 to displace along the X-axis guide rail 201. A second displacement device 204 capable of displacement along the Y-axis guide rail 202 is provided on the Y-axis guide rail 202. An electrically controlled telescopic device 205 is vertically attached to the second displacement device 204, which is capable of extending and retracting along the Z-axis. A scanning device 207 is secured to the distal end of the telescopic device 205 via an electrically controlled pan / tilt platform 206. The first displacement device 203 , the second displacement device 204 , the electric-controlled telescopic device 205 , and the electric-controlled pan / tilt platform 206 are respectively connected to the control system signal.

[0462] As shown in Figure 5 , the electronically controlled pan / tilt platform 206 comprises a fixed platform 2061 secured to the electronically controlled telescopic device 205, and a rotating platform 2062 rotatably connected to the fixed platform 2061 and capable of rotating relative to the fixed platform 2061 along a vertical axis. The rotating platform 2062 is rotatably connected to the fixed end of a second electronically controlled telescopic device 2064 via a speed reducer 2063. The speed reducer 2063 controls the horizontal rotation of the second electronically controlled telescopic device 2064. The scanning device 207 is secured to the telescopic end of the second electronically controlled telescopic device 2064.

[0463] As shown in FIG6 , the scanning device 207 includes an imaging device 2071, a thermal imager 2072, a scanning distance measuring device 2073, and an infrared temperature measuring device 2074. The imaging device 2071 is used to obtain image data of the ceramic shell 4 to be dried. The scanning distance measuring device 2073 is used to measure the distance between the ceramic shell 4 to be dried and the scanning device 207 in real time.

[0464] The control system includes: a vacuum drying control module, a fan unit control module, a ceramic shell analysis module, a scanning device control module, and a drying process analysis module.

[0465] The vacuum drying control module controls the opening and closing of the vacuum pump 8 , the first electrically controlled switch valve 10 , and the second electrically controlled valve 107 .

[0466] The ceramic shell analysis module acquires image data of the ceramic shell 4 to be dried and performs a model structure analysis to determine the location, orientation, and depth of the deep holes in the ceramic shell 4 to be dried. The module then transmits this information to the fan unit control module. The fan unit control module then performs a fan unit control analysis based on the location, orientation, and depth of the deep holes in the ceramic shell 4 to be dried, and controls the on / off and / or control parameters of each fan unit based on the analysis results.

[0467] The scanning device control module is used to control the movement of the two first displacement devices 203, the second displacement device 204, the electric-controlled telescopic device 205, and the electric-controlled pan-tilt platform 206, so that the scanning device 207 can perform omnidirectional photography / scanning on the ceramic shell 4 to be dried to obtain images / scanning data of the ceramic shell 4 to be dried.

[0468] The drying process analysis module obtains the measurement data of the infrared temperature measuring device 2074 to perform drying process analysis to determine whether the ceramic shell 4 to be dried is completely dried.

[0469] The model structure analysis method comprises:

[0470] Step 1.1 The scanning distance measuring device 2073 performs a full-scale scan of the surface n of the ceramic shell 4 to be dried according to a preset route, and obtains a distance measurement data set G of all scanning points on the surface n relative to the scanning distance measuring device 2073. n .

[0471] Step 1.2 The ranging data set G n The end points are connected to obtain the digital surface m of the surface n of the ceramic shell 4 to be dried.

[0472] Step 1.3: Graphically analyze the digital surface m of the ceramic shell 4 to be dried in combination with the image data to determine the basic surface, convex surface, and concave surface of the digital surface m.

[0473] Step 1.4 Calculate the difference C between each distance measurement point on the groove surface and each distance measurement point on the adjacent basic surface of the groove mk-b , where mk is the groove numbered k on the digital surface m, and b is the separate number of the distance measurement point in the groove mk.

[0474] Step 1.5 Take C mk-b >K2 is a deep hole, take C mk-b >K3 is a through hole, wherein K2 is a preset deep hole judgment threshold, and K3 is a model width, model length, or model height corresponding to the surface n of the ceramic shell 4 to be dried.

[0475] Step 1.6 Count the positions W of all deep holes on the digital surface m of the ceramic shell to be dried mc The depth H corresponding to each deep hole mc , where c is the natural number of the deep hole on the digital surface m.

[0476] Step 1.7 Repeat steps 1.1 to 1.6 until all the deep holes on the surface of the ceramic shell 4 to be dried can be scanned. mc , depth H mc Statistics are completed, and the deep hole direction X is determined based on the surface n where the deep hole is located mc .

[0477] Step 1.8 Output the position W of all deep holes on the surface of the ceramic shell 4 to be dried mc , depth H mc , towards X mc data.

[0478] Step 2.1: According to the deep hole position, control the scanning distance measuring device 2073 to move to the deep hole position.

[0479] Step 2.2: Acquire multiple deep hole depth measurement data by adjusting the orientation of the scanning distance measuring device 2073 relative to the deep hole.

[0480] Step 2.3 Use the deepest depth measurement data to correct the original deep hole depth data H m-c , get the corrected data H m-c `.

[0481] The method for obtaining the basic surface, the convex surface and the concave surface comprises:

[0482] Step 1.3.1: Obtain image data corresponding to the digital surface m of the ceramic shell 4 to be dried, and obtain an image surface R by splicing the image data.

[0483] Step 1.3.2 performs element recognition on the image surface R to obtain element regions rn-m on the image surface R, where rn is the sequential number of the element regions in the digital surface m.

[0484] Step 1.3.3: Adjust the digital surface m to have the same orientation and similar size as the image surface R.

[0485] In step 1.3.4, the element region rc-m with the largest continuous area is taken as the base surface, and the rc-m belongs to rn-m.

[0486] Step 1.3.5 obtains the distance measurement point data of each non-basic surface feature area, where the feature area distance measurement points that are greater than the distance to the adjacent basic surface distance measurement points are groove points, and the feature area distance measurement points that are less than the distance to the adjacent basic surface distance measurement points are convex points.

[0487] In step 1.3.6, the adjacent groove points and convex points are connected to form groove surfaces and convex surfaces based on the element area.

[0488] The drying process analysis includes: measuring the temperature T inside the deep hole regularly or continuously. v - Curve Q of drying time t v , when Q v When all curve segments that conform to the preset curve rule appear, it indicates that the drying of the ceramic shell 4 to be dried is completed. Wherein v is the natural number of all the deep holes of the ceramic shell 4 to be dried.

[0489] The preset curve pattern, as shown in FIG9 , includes the following steps: the temperature T inside the deep hole gradually decreases from the initial drying temperature T1 to a temperature T2 over the drying time, and then gradually increases to the drying environment temperature T3 over the drying time. When the temperature T of the deep hole of the ceramic shell 4 to be dried passes through the interval T1-T2-T3 and remains at the drying environment temperature T3 for a preset time U, drying is considered complete. The initial drying temperature T1 is 22-26°C, the temperature T2 is 5-7°C lower than the temperature T1, and the drying environment temperature T3 is 24±1°C.

[0490] When there are multiple ceramic shells 4 to be dried, the method for determining whether the drying of the ceramic shells 4 is complete includes: detecting the temperature of each deep hole of each ceramic shell 4 to be dried one by one, and determining that the drying of the entire batch of ceramic shells 4 to be dried is complete when more than L% of the ceramic shells 4 to be dried are dried. The L%=(L g-d ) / (L 0-d )*100%, where L g-d is the number of ceramic shells 4 to be dried after drying in batch d, L 0-dis the number of all the ceramic shells 4 to be dried in batch d. The value of L% is: 100% ≥ L% ≥ E%. Where E is the preset threshold value of the minimum drying completion percentage of all the ceramic shells 4 to be dried in batch d.

[0491] The fan group control analysis includes: fan group control analysis method A, fan group control analysis method B, fan group control analysis method C, and fan group control analysis method D. Among them:

[0492] Fan group control analysis method A, including:

[0493] For all fan units p with deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0494] Step 3.1 Obtain the total number of deep holes D0 of the ceramic shell 4 to be dried, and obtain the total number of deep holes D0 of the surface of the ceramic shell 4 to be dried facing the fan group p. p The p is the number of the fan units arranged on different sides of the vacuum drying chamber 1.

[0495] Step 3.2 Calculate k S-p % = D p / D0*100%, the k S-p % is the control parameter of fan group p.

[0496] Step 3.3 Repeat steps 3.1 to 3.2 to obtain k for all fan groups S-p %.

[0497] For all fan units P that do not have deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0498] Calculate k F-p % = [1-D0 / (D0+1)] * 100%, the k F-p % is the control parameter of fan group p.

[0499] The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

[0500] Fan group control analysis method B, including:

[0501] For all fan units p with deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0502] Step 4.1 Obtain the total number of deep holes D0 of the ceramic shell 4 to be dried, and obtain the total number of deep holes D0 on the surface of the ceramic shell 4 to be dried facing the fan group p. pThe p is the number of the fan units arranged on different sides of the vacuum drying chamber 1.

[0503] Step 4.2 According to D0 and D p The number of k is obtained from the control parameter database S-p %. The k S-p % is the control parameter of fan group p.

[0504] Step 4.3 Repeat steps 4.1 to 4.2 to obtain the k of all fan groups. S-p %.

[0505] For all fan units P that do not have deep holes on the surface of the ceramic shell 4 to be dried, the following method is adopted:

[0506] According to the total number of deep holes D0 of the ceramic shell 4 to be dried, k is obtained from the control parameter database. F-p %. The k F-p % is the control parameter of fan group p.

[0507] The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

[0508] The k S-p % and k F-p % of methods include:

[0509] Step 5.1: Simulate the same position and orientation of the fan unit as that of the target vacuum drying chamber 1 in the simulation device.

[0510] Step 5.2 Preset the deep hole distribution of different ceramic shells 4 to be dried for drying training, and determine the control parameter k of each fan group p relative to full load corresponding to the optimal drying time under each deep hole distribution condition. S-p % and k F-p %; the deep hole distribution includes: deep hole direction and number; the optimal drying time is the shortest time for the deep holes and the surface of the ceramic shell 4 to be dried to complete the synchronous drying;

[0511] Step 5.3 Repeat step 5.2 until the deep hole distribution under normal conditions is trained and D0-D p —k S-p %—k F-p % of the deep hole-control parameter relationship group and store it in the control parameter database.

[0512] Fan group control analysis method C includes:

[0513] Step 6.1 constructs a three-dimensional coordinate system based on the scanning starting point preset by the scanning device 207.

[0514] Step 6.2: The scanning device 207 records the three-dimensional coordinate points in the process of displacement, and in the process of model structure analysis, the deep hole position, direction and depth of the ceramic shell 4 to be dried are marked with three-dimensional coordinate points.

[0515] Step 6.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p.

[0516] Step 6.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up .

[0517] Step 6.5 Calculate k up-e %=(D up-e / D up )*k S-p %.

[0518] The fan group control module obtains the k of each fan in the fan group p. up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % Run. For D up-e =0, the fan operates at the lowest power.

[0519] Fan group control analysis method D, including:

[0520] Step 7.1 constructs a three-dimensional coordinate system based on the scanning starting point preset by the scanning device 207.

[0521] Step 7.2: The scanning device 207 records the three-dimensional coordinate points in the process of displacement, and in the process of model structure analysis, the deep hole position, direction and depth of the ceramic shell 4 to be dried are marked with three-dimensional coordinate points.

[0522] Step 7.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p.

[0523] Step 7.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up .

[0524] Step 7.5 According to D up and Dup-e Get the k value of the corresponding fan from the control parameter database up-e %, the k up-e % is the control parameter of the fan numbered e in the fan group p.

[0525] The fan group control module obtains the k of each fan in the fan group p. up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % to run.

[0526] The k up-e % methods, specifically including:

[0527] Step 8.1: Simulate the same position and orientation of the fan unit as that of the target vacuum drying chamber 1 in the simulation device.

[0528] Step 8.2 Preset the deep hole distribution of different ceramic shells 4 to be dried for drying training, and determine the operation ratio k of each fan in each fan group p when the fan is relatively fully loaded corresponding to the optimal drying time under each deep hole distribution condition. up-e The deep hole distribution includes the direction and number of the deep holes. The optimal drying time is the shortest time for the deep holes and the surface layer of the ceramic shell 4 to be dried to be synchronously dried.

[0529] Step 8.3 Repeat step 8.2 until the deep hole distribution under normal conditions is trained and D up —D up-e —k up-e % of the deep hole-control parameter relationship group and store it in the control parameter database.

[0530] For the ceramic shells 4 to be dried for which data is entered in the control parameter database, the drying is performed using the fan group control analysis method B+D. For the ceramic shells 4 to be dried for which data is not entered in the control parameter database, the drying is performed using the fan group control analysis method A+C.

[0531] The method for making the drying time of each part of the ceramic shell to be dried tend to be consistent includes:

[0532] Step 9.1: During the drying process of the ceramic shell 4 to be dried, the thermal imager 2072 and the scanning device 207 take real-time thermal imaging photos of the ceramic shell 4 to be dried, and send the photos to the control system.

[0533] Step 9.2: The control system determines, based on the heat distribution in the thermal imaging image, whether there is an area T with a high / low temperature difference exceeding a preset temperature difference threshold when the drying time exceeds the preset first drying time. If there is an area T, the control system performs the following determination and operation:

[0534] When the temperature of the low-temperature area of ​​region T is lower than the preset low-temperature threshold, the operating power of the fan group corresponding to region T is reduced.

[0535] When the temperature of the high temperature area of ​​region T is higher than the preset high temperature threshold, the operating power of the fan group corresponding to region T is increased.

[0536] When the existence time of area T exceeds the preset time threshold, and the temperature of the low temperature area of ​​area T is higher than the preset low temperature threshold, and the temperature of the high temperature area of ​​area T is lower than the preset high temperature threshold, the operating power of the fan group corresponding to area T is increased.

[0537] The preset low temperature threshold is: 14°C.

[0538] The preset high temperature threshold is: 27°C.

[0539] The preset first drying time is: 2 minutes.

[0540] The preset time threshold is: 50 seconds.

[0541] After placing the ceramic shells to be dried into the vacuum rapid drying system and letting them stand for 60 seconds, the vacuum rapid drying process is carried out. The vacuum rapid drying process comprises:

[0542] When drying the surface layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 750-720 mmHg within 5 seconds. Then, restore the vacuum level from 750-720 mmHg to atmospheric pressure within 5 seconds. Repeat this process until the surface layer is completely dried.

[0543] When drying the transition layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 720-680 mmHg within 7 seconds. Then, restore the vacuum level from 720-680 mmHg to atmospheric pressure within 7 seconds. Repeat this process until the transition layer is completely dried.

[0544] The support layer is provided with at least three layers in sequence from the transition layer to the sealing layer. When drying the support layer, the following steps are included:

[0545] The inner surface of the first support layer is bonded to the outer surface of the transition layer, and the vacuum rapid drying process of the first support layer is performed, including the following steps:

[0546] Step 11.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-220 mmHg within 30 seconds.

[0547] Step 11.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0548] In step 11.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0549] In step 11.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 260-220 mmHg within 30 seconds.

[0550] In step 11.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0551] Step 11.6 Repeat steps 11.4 and 11.5 until the first layer of the support layer is dry.

[0552] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0553] Step 12.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 200-150 mmHg within 30 seconds.

[0554] Step 12.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0555] In step 12.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0556] In step 12.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 200-150 mmHg within 30 seconds.

[0557] In step 12.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0558] Step 12.6 Repeat steps 12.4 and 12.5 until the second layer of support layer is dry.

[0559] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0560] Step 13.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0561] Step 13.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0562] Step 13.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds.

[0563] Step 13.4: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0564] In step 13.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds.

[0565] Step 13.6 Repeat steps 13.4 and 13.5 until the third support layer is dry.

[0566] The inner surface of the sealing layer is in contact with the outer surface of the third layer of the supporting layer.

[0567] When drying the sealing layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 120-90 mmHg within 40 seconds. Then, return the vacuum level of the ceramic shell to atmospheric pressure within 120 seconds. Repeat this process until the sealing layer is completely dried.

[0568] Ceramic shell preparation method 2, comprising:

[0569] S1. Apply a corresponding number of layers of ceramic shell slurry to the outside of the wax mold layer by layer, and obtain the corresponding layers of ceramic shell to be dried after each application of the ceramic shell slurry.

[0570] S2. Each corresponding layer of the ceramic shell to be dried is placed in a vacuum rapid drying system for vacuum rapid drying. After the drying of the ceramic shell of the layer is completed, the ceramic shell slurry of the next layer is applied.

[0571] S3. After all layers of the ceramic shell are dried, the ceramic shell for precision casting is obtained.

[0572] The vacuum rapid drying system includes a vacuum drying chamber 1, a vacuum pump 8, and a control system. The vacuum pump 8 evacuates the vacuum drying chamber 1. The vacuum pump 8 is connected to the vacuum drying chamber 1 via a first connecting pipe, which is equipped with a first electrically controlled on / off valve 10. An air pipe 106 is connected to the vacuum drying chamber 1, which is equipped with a second electrically controlled valve 107.

[0573] A drying rack 3 is detachably mounted within the vacuum drying chamber 1, and the ceramic shell 4 to be dried is detachably mounted on the drying rack 3 for drying. A first blower unit 101 is provided at the top of the drying rack 3, a second blower unit 102 is provided at the bottom of the drying rack 3, a third blower unit 103 is provided on the opening and closing door of the vacuum drying chamber 1, and a fourth blower unit 104 and a fifth blower unit 105 are provided on either side of the drying rack 3 along the axial direction of the vacuum drying chamber 1. An adjustable component 108 is provided on the opposite side of the third blower unit 103. The adjustable component 108 is a sixth blower unit.

[0574] After placing the ceramic shells to be dried into the vacuum rapid drying system and letting them stand for 60 seconds, the vacuum rapid drying process is carried out. The vacuum rapid drying process comprises:

[0575] When drying the surface layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 750-720 mmHg within 5 seconds. Then, restore the vacuum level from 750-720 mmHg to atmospheric pressure within 5 seconds. Repeat this process until the surface layer is completely dried.

[0576] When drying the transition layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 720-680 mmHg within 7 seconds. Then, restore the vacuum level from 720-680 mmHg to atmospheric pressure within 7 seconds. Repeat this process until the transition layer is completely dried.

[0577] The support layer is provided with at least three layers in sequence from the transition layer to the sealing layer. When drying the support layer, the following steps are included:

[0578] The inner surface of the first support layer is bonded to the outer surface of the transition layer, and the vacuum rapid drying process of the first support layer is performed, including the following steps:

[0579] Step 11.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 260-220 mmHg within 30 seconds.

[0580] Step 11.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0581] In step 11.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0582] In step 11.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 260-220 mmHg within 30 seconds.

[0583] In step 11.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds.

[0584] Step 11.6 Repeat steps 11.4 and 11.5 until the first layer of the support layer is dry.

[0585] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0586] Step 12.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 200-150 mmHg within 30 seconds.

[0587] Step 12.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0588] In step 12.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0589] In step 12.4, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 200-150 mmHg within 30 seconds.

[0590] In step 12.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds.

[0591] Step 12.6 Repeat steps 12.4 and 12.5 until the second layer of support layer is dry.

[0592] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0593] Step 13.1: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0594] Step 13.2: Maintain the vacuum degree of the ceramic shell to be dried at a negative pressure for 4-6 minutes.

[0595] Step 13.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds.

[0596] Step 13.4: Reduce the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds.

[0597] In step 13.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds.

[0598] Step 13.6 Repeat steps 13.4 and 13.5 until the third support layer is dry.

[0599] The inner surface of the sealing layer is in contact with the outer surface of the third layer of the supporting layer.

[0600] When drying the sealing layer: First, reduce the vacuum level of the ceramic shell from atmospheric pressure to 120-90 mmHg within 40 seconds. Then, return the vacuum level of the ceramic shell to atmospheric pressure within 120 seconds. Repeat this process until the sealing layer is completely dried.

[0601] During the vacuum rapid drying process, the control system controls the fan unit in the vacuum rapid drying system to operate at a fixed wind direction and rated power. Each layer of the ceramic shell is judged to be dried after a preset time based on work experience or operating instructions.

[0602] The ceramic shell preparation method 3 comprises:

[0603] S1. Apply a corresponding number of layers of ceramic shell slurry to the outside of the wax mold layer by layer, and obtain the corresponding layers of ceramic shell to be dried after each application of the ceramic shell slurry.

[0604] S2. Each corresponding layer of the ceramic shell to be dried is placed in a vacuum rapid drying system for vacuum rapid drying. After the drying of the ceramic shell of the layer is completed, the ceramic shell slurry of the next layer is applied.

[0605] S3. After all layers of the ceramic shell are dried, the ceramic shell for precision casting is obtained.

[0606] Step S2 is carried out using the ceramic shell rapid drying method and device of ZL 201610416881.4.

[0607] Example 1

[0608] A ceramic shell, as shown in Figure 7, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component used by workers to apply slurry and is not a cast structure. The ceramic shell is prepared using a thick slurry using ceramic shell preparation method 1.

[0609] Example 2

[0610] A ceramic shell, as shown in Figure 7, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component used by workers to apply slurry and is not a cast structure. The ceramic shell is prepared using a thick slurry using ceramic shell preparation method 2.

[0611] Example 3

[0612] A ceramic shell, as shown in Figure 7, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component used by workers to apply slurry and is not a cast structure. The ceramic shell is prepared using a thick slurry using ceramic shell preparation method 3.

[0613] Comparative Example 1

[0614] A ceramic shell, as shown in Figure 7, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component used by workers to apply sizing and is not a cast structure. This ceramic shell was prepared using ceramic shell preparation method 1 with a thin slurry. To achieve the same support strength as the ceramic shell obtained in Example 1, the number of support layers is five.

[0615] Comparative Example 2

[0616] A ceramic shell, as shown in Figure 7, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component used by workers to apply sizing and is not a cast structure. This ceramic shell was prepared using ceramic shell preparation method 3 with a thin slurry. To achieve the same support strength as the ceramic shell obtained in Example 1, the number of support layers is five.

[0617] Comparative Example 3

[0618] A ceramic shell, as shown in Figure 7, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component used by workers to hold the shell during sizing and is not a cast structure. The ceramic shell is prepared from a concentrated slurry and dried using hot air at 120°C at normal pressure.

[0619] The ceramic shells obtained in Examples 1-3 and Comparative Examples 1-3 were tested for breaking strength coefficient, ceramic shell thickness, total drying time, and drying yield rate. The test results are shown in Table 1.

[0620] Table 1. Test results of breaking strength coefficient, ceramic shell thickness, total drying time, and drying yield rate of Examples 1-3 and Comparative Examples 1-3.

[0621] As can be seen from the table above:

[0622] (1) Comparison between Example 1 and Example 2 shows that, compared with the technology of adopting multi-directional fixed wind direction and fixed fan power, the present invention adjusts the control parameters of the fans in each direction during the drying of the ceramic shell. Under the control of the same vacuum drying vacuum degree and other control parameters, the ceramic shell drying time of the present invention is slightly improved. However, since the drying time of each part of the ceramic shell is almost the same during the drying process of the ceramic shell of the present invention, the drying yield of the ceramic shell is significantly improved.

[0623] (2) Comparison between Example 1 and Example 3 shows that, compared with the existing vacuum rapid drying technology, the performance of the ceramic shell obtained by the present invention is significantly improved when drying the concentrated slurry ceramic shell, and the drying yield of the ceramic shell can also be significantly improved. The main reason for the unstable drying time in Example 3 is that the existing technology uses fixed wind on both sides and rotating ceramic shells for vacuum rapid drying. When the deep hole faces the windward side, the drying time is relatively short. When the deep hole faces the leeward side, the drying time is relatively long, and the problem of over-drying of the windward side is prone to occur, that is, the drying yield of the ceramic shell decreases.

[0624] (3) Comparison of Example 1 with Comparative Examples 1 and 2 shows that the present invention can promote the expansion of the ceramic shell support layer to obtain a ceramic shell support layer with a higher thickness, thereby reducing the fracture strength coefficient of the ceramic shell. Since thin-slurry ceramic shells contain less material, the thickness of the ceramic shell that can expand is less than that of thick-slurry ceramic shells. Therefore, in order to achieve the necessary ceramic shell thickness to provide sufficient support for the ceramic shell, it is necessary to increase the number of support layers, which leads to an increase in the overall drying time (number of layers * drying time).

[0625] (4) From the comparison of Example 1, Example 3 and Comparative Example 3, it can be seen that the drying yield rate of the thick slurry ceramic shell prepared by the present invention has been significantly improved. This is mainly due to the fact that the present invention significantly shortens the drying time while ensuring that the drying process tends to be consistent. However, when the existing prior art dries the thick slurry ceramic shell, the drying time is too long. The drying of the ceramic shell is a cooling process of water volatilization, that is, during the volatilization of the water in the ceramic shell, the temperature of the ceramic shell will drop by about 6°C. At this time, the wax mold will also be affected by the low temperature of the ceramic shell and cool down and shrink. Since the drying of the ceramic shell is also a shrinkage process, the ceramic shell will shrink with the shrinkage of the wax mold. When the drying time is too long, the shrinkage ratio of the wax mold will increase, resulting in a relatively large shrinkage of the ceramic shell after drying. When the drying is completed, the ceramic shell as a whole will return to room temperature. At this time, the wax mold will expand and cause cracks to appear at the part where the ceramic shell surface layer and the wax mold are in contact, which seriously affects the drying yield rate of the ceramic shell. However, due to the shorter drying time of the present invention, the shrinkage rate of the wax mold due to the influence of low temperature is small, which generally does not cause cracks in the part where the ceramic shell surface layer and the wax mold are in contact, thereby improving the drying yield of the thick slurry ceramic shell.

[0626] Example 4

[0627] A ceramic shell, as shown in Figure 6, includes a deep hole 401 and a gripping portion 402. Deep hole 401 is a cast structure, while gripping portion 402 is a component held by workers during sizing and is not a cast structure. This ceramic shell is prepared using a concentrated slurry using ceramic shell preparation method 4. Compared to ceramic shell preparation method 1, ceramic shell preparation method 4 has the following differences:

[0628] 1. The vacuum rapid drying system also includes a vacuum tank 5. One end of the vacuum tank 5 is connected to a vacuum pump 8 via a second connecting pipe, which is equipped with a third electrically controlled valve 9. The other end of the vacuum tank 5 is connected to the vacuum drying chamber 1 via a third connecting pipe 7, which is equipped with a fourth electrically controlled valve 6.

[0629] 2. When vacuum drying the support layer and the sealing layer, use the following method:

[0630] The inner surface of the first support layer is bonded to the outer surface of the transition layer, and the vacuum rapid drying process of the first support layer is performed, including the following steps:

[0631] Step 14.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank 5 maintains vacuum.

[0632] Step 14.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank 5.

[0633] In step 14.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank 5 continues to be evacuated.

[0634] Step 14.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank 5 maintains vacuum.

[0635] In step 14.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank 5 continues to be evacuated.

[0636] Step 14.6 Repeat steps 14.4 and 14.5 until the first layer of the support layer is dried.

[0637] The inner surface of the second supporting layer is attached to the outer surface of the first supporting layer, and the vacuum rapid drying process of the second supporting layer is performed, including the following steps:

[0638] Step 15.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank 5 maintains vacuum.

[0639] Step 15.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank 5.

[0640] In step 15.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank 5 continues to be evacuated.

[0641] Step 15.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank 5 maintains vacuum.

[0642] In step 15.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank 5 continues to be evacuated.

[0643] Step 15.6 Repeat steps 15.4 and 15.5 until the second layer of the support layer is dried.

[0644] The inner surface of the third support layer is attached to the outer surface of the second support layer, and the vacuum rapid drying process of the third support layer is performed, including the following steps:

[0645] Step 16.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank 5 maintains vacuum.

[0646] Step 16.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank 5.

[0647] In step 16.3, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank 5 continues to be evacuated.

[0648] Step 16.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank 5 maintains vacuum.

[0649] In step 16.5, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank 5 continues to be evacuated.

[0650] Step 16.6 Repeat steps 16.4 and 16.5 until the third support layer is dried.

[0651] The inner surface of the sealing layer is attached to the outer surface of the third layer of the support layer, and the vacuum rapid drying process of the sealing layer is performed, which includes the following steps:

[0652] Step 17.1 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 35 seconds, while the vacuum tank 5 maintains vacuum.

[0653] In step 17.2, the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 120 seconds, and the vacuum tank 5 continues to be evacuated.

[0654] Step 17.3 Repeat steps 17.1 and 17.2 until the sealing layer is completely dry.

[0655] The instantaneous voltage reduction operation includes:

[0656] First, before reducing the pressure, the fourth electrically controlled valve 6 is closed, and the vacuum tank 5 is evacuated to a low vacuum state in advance.

[0657] Then, when the pressure is reduced, the fourth electrically controlled valve 6 is opened to connect the vacuum drying chamber 1 with the vacuum tank 5, and the pressure is instantly reduced to the equilibrium low pressure within 0.5 seconds.

[0658] Finally, the vacuum pump 8 simultaneously extracts the gaseous components in the vacuum tank 5 and the vacuum drying chamber 1, so that the vacuum degree in the vacuum drying chamber 1 meets the preset target, and then closes the fourth electrically controlled valve 6 and the first electrically controlled switch valve 10. At the same time, the vacuum pump 8 continues to extract the gaseous components in the vacuum tank 5 to the vacuum tank 5 to a low vacuum state.

[0659] The ceramic shells obtained in Example 1 and Example 4 were tested for breaking strength coefficient, ceramic shell thickness, total drying time, and drying yield rate. The test results are shown in Table 2.

[0660] Table 2. Test results of breaking strength coefficient, ceramic shell thickness, total drying time, and drying yield rate of Example 1 and Example 4.

[0661] As can be seen from the table above:

[0662] Through the instantaneous pressure reduction action, the breaking strength coefficient of the obtained ceramic shell can be further reduced, and the thickness of the obtained ceramic shell can be further increased, so that while maintaining sufficient supporting force, the thick slurry ceramic shell also has an excellent breaking strength coefficient, which improves the applicability of the thick slurry ceramic shell in precision casting.

[0663] Example 5

[0664] A ceramic shell, as shown in FIG10 , is of conventional configuration and is provided with a gripping portion 402 , which is a component held by a worker during sizing and is not a casting structure. The ceramic shell is prepared using a thick slurry using ceramic shell preparation method 1 .

[0665] Example 6

[0666] A ceramic shell, as shown in FIG10 , is of conventional configuration and is provided with a gripping portion 402 , which is a component held by a worker during sizing and is not a casting structure. The ceramic shell is prepared using a thick slurry using ceramic shell preparation method 2 .

[0667] The ceramic shells obtained in Examples 1-2 and 5-6 were tested for breaking strength coefficient, ceramic shell thickness, total drying time, and drying yield rate. The test results are shown in Table 3.

[0668] Table 3. Test results of breaking strength coefficient, ceramic shell thickness, total drying time, and drying yield rate of Examples 1-2 and 5-6.

[0669] As can be seen from the table above:

[0670] (1) When the configuration of the component to be cast is relatively simple, the total drying time and drying yield of the present invention are closer than those of the technology with fixed wind direction.

[0671] (2) When the configuration of the component to be cast is relatively complex, the present invention can significantly improve the drying yield rate although the total drying time is slightly increased compared with the technology of fixed wind direction.

[0672] It can be seen that the ceramic shell preparation method of the present invention achieves similar production efficiency and success rate to fixed-wind technology when preparing ceramic shells with simple configurations, while significantly improving the technical effect when preparing ceramic shells with complex configurations. Therefore, the ceramic shell preparation method of the present invention not only produces ceramic shells with good performance, but is also suitable for preparing ceramic shells of various configurations, showing wide applicability, and is particularly suitable for preparing ceramic shells with complex configurations.

[0673] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a ceramic shell for precision casting, characterized in that: include: S1. Apply the corresponding number of layers of ceramic shell slurry layer by layer on the outside of the wax mold, and after each application of the ceramic shell slurry, the corresponding layers of ceramic shell to be dried are obtained in turn; S2. Each corresponding layer of the ceramic shell to be dried is placed in a vacuum rapid drying system for vacuum rapid drying. After the ceramic shell layer is dried, the ceramic shell slurry coating operation of the next layer is performed; When performing the vacuum rapid drying process, the model information of the ceramic shell to be dried is first obtained, and then the control parameters of the blowers on different sides of the ceramic shell to be dried are adjusted according to the model information, so that the drying time of each part of the ceramic shell to be dried tends to be consistent; The vacuum rapid drying system comprises: a vacuum drying chamber (1), a vacuum pump (8) and a control system; the vacuum pump (8) performs a vacuum treatment on the vacuum drying chamber (1); a drying rack (3) is provided inside the vacuum drying chamber (1), and the ceramic shell (4) to be dried is arranged on the drying rack (3) for drying treatment; at least two groups of fan units with different wind directions are provided around the drying rack (3) inside the vacuum drying chamber (1); The control system comprises: a vacuum drying control module and a fan group control module; the vacuum drying control module controls the vacuum drying chamber (1) to evacuate and / or restore the chamber pressure, and the fan group control module controls the start and stop and / or control parameters of all fan groups, so that the drying time of each part of the ceramic shell to be dried tends to be consistent; A three-dimensional detection mechanism (2) is provided inside the vacuum drying chamber (1); the three-dimensional detection mechanism (2) drives the scanning device (207) to move along the X-axis, the Y-axis, and the Z-axis; The scanning device (207) comprises at least: an imaging device (2071); the imaging device (2071) is used to obtain image data of the ceramic shell (4) to be dried; The control system comprises: a ceramic shell analysis module; the ceramic shell analysis module acquires image data of the ceramic shell (4) to be dried and performs model structure analysis to obtain the deep hole position, orientation and depth, and sends it to the fan group control module; the fan group control module performs fan group control analysis according to the deep hole position, direction and depth of the ceramic shell (4) to be dried, and controls the start and stop and / or control parameters of each fan group according to the analysis results; S3. When all layers of the ceramic shell are dried, the ceramic shell for precision casting is obtained.

2. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The vacuum pump (8) is connected to the vacuum drying chamber (1) via a first connecting pipe, and a first electrically controlled switch valve (10) is provided on the first connecting pipe; the vacuum drying chamber (1) is connected to an air pipe (106), and a second electrically controlled valve (107) is provided on the air pipe (106); the vacuum drying control module controls the vacuum pump (8), the first electrically controlled switch valve (10), and the second electrically controlled valve (107) to evacuate the vacuum drying chamber (1) and / or restore the chamber pressure.

3. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The vacuum drying chamber (1) is provided with a controller component; the controller component receives a control signal and sends it to a fan group control module to control the start and stop and / or control parameters of each fan group; the controller comprises: at least one of a knob controller, a button controller, a touch screen controller, and a toggle switch.

4. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The three-dimensional detection mechanism (2) comprises: two X-axis guide rails (201) arranged horizontally along the axial direction of the vacuum drying chamber (1) and parallel to each other and respectively located on both sides of the drying frame (3); and a Y-axis guide rail (202) arranged horizontally along the cross-sectional direction of the vacuum drying chamber (1); the two X-axis guide rails (201) are respectively provided with a first displacement device (203) that can be displaced along the X-axis guide rail (201); the Y-axis guide rail (202) is fixed between the two first displacement devices (203) and is driven by the two first displacement devices (203) to move along the X-axis guide rail ( 201) displacement; the Y-axis guide rail (202) is provided with a second displacement device (204) that can be displaced along the Y-axis guide rail (202); the second displacement device (204) is provided with an electric-controlled telescopic device (205) that can be telescoped along the Z-axis direction in the vertical direction; the telescopic end of the electric-controlled telescopic device (205) is fixed with a scanning device (207) through an electric-controlled pan-tilt table (206); the first displacement device (203), the second displacement device (204), the electric-controlled telescopic device (205), and the electric-controlled pan-tilt table (206) are respectively connected to control system signals.

5. The method for preparing a ceramic shell for precision casting according to claim 4, characterized in that: The control system comprises: a scanning device control module; the scanning device control module is used to control the movement of two first displacement devices (203), a second displacement device (204), an electric-controlled telescopic device (205), and an electric-controlled pan-tilt platform (206), so that the scanning device (207) performs omnidirectional shooting / scanning on the ceramic shell (4) to be dried, thereby obtaining images / scanning data of the ceramic shell (4) to be dried.

6. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The model structure analysis includes image analysis: First, the outer contour model data, deep hole position data, and deep hole depth data of the ceramic shell (4) to be dried are obtained; Then, the acquired image data is compared with the outer contour model data to determine the spatial orientation of the ceramic shell (4) to be dried currently hung in the vacuum drying chamber (1); Finally, the current deep hole position and orientation of the ceramic shell (4) to be dried are determined according to the spatial orientation of the ceramic shell (4) to be dried, and the current deep hole position, orientation and depth data corresponding to the deep hole of the ceramic shell (4) to be dried are output.

7. The method for preparing a ceramic shell for precision casting according to claim 5, characterized in that: The scanning device (207) further comprises: a scanning distance measuring device (2073); the scanning distance measuring device (2073) is used to measure in real time the distance between the ceramic shell (4) to be dried and the scanning device (207); The model structure analysis includes: Step 1.1 The scanning distance measuring device (2073) performs a full-scale scan on the surface n of the ceramic shell (4) to be dried according to a preset route, and obtains a distance measurement data set G of all scanning points on the surface n relative to the scanning distance measuring device (2073). n ; Step 1.2: The ranging data set G n The end points are connected to obtain a digital surface m of the surface n of the ceramic shell (4) to be dried; Step 1.3: Performing graphic analysis on the digital surface m of the ceramic shell (4) to be dried in combination with the image data to determine the basic surface, the convex surface and the concave surface of the digital surface m; Step 1.4 Calculate the difference C between each distance measurement point on the groove surface and each distance measurement point on the adjacent basic surface of the groove mk-b , where mk is the groove numbered k on the digital surface m, and b is the other number of the distance measurement point in the groove mk; Step 1.5 Take C mk-b >K2 is a deep hole, take C mk-b >K3 is a through hole; wherein K2 is a preset deep hole judgment threshold, and K3 is a model width or a model length or a model height corresponding to the surface n of the ceramic shell (4) to be dried; Step 1.6 Count the positions W of all deep holes on the digital surface m of the ceramic shell to be dried (4) mc The depth H corresponding to each deep hole mc , where c is the natural number of the deep hole on the digital surface m; Step 1.7 Repeat steps 1.1 to 1.6 until all the deep holes on the surface of the ceramic shell (4) to be dried can be scanned. mc , depth H mc Statistics completed, determine the deep hole direction X according to the deep hole surface n mc ; Step 1.8 Output the positions W of all the deep holes on the surface of the ceramic shell (4) to be dried mc , depth H mc , towards X mc data.

8. The method for preparing a ceramic shell for precision casting according to claim 7, characterized in that: The method for obtaining the basic surface, the convex surface and the concave surface in step 1.3 includes: Step 1.3.1: obtaining image data corresponding to the digital surface m of the ceramic shell (4) to be dried, and obtaining an image surface R by splicing the image data; Step 1.3.2: perform element recognition on the image surface R to obtain element regions rn-m on the image surface R, where rn is the sequential number of the element regions in the digital surface m; Step 1.3.3: Adjust the digital surface m to have the same orientation and similar size as the image surface R; Step 1.3.4: take the element region rc-m with the largest continuous area as the base surface, and the rc-m belongs to rn-m; Step 1.3.5 obtains the distance measurement point data of each non-basic surface element area, wherein the distance measurement point of the element area that is greater than the distance of the adjacent basic surface distance measurement point is a groove point, and the distance measurement point of the element area that is less than the distance of the adjacent basic surface distance measurement point is a convex point; Step 1.3.6 uses the element area as the boundary and connects adjacent groove points and convex points to form groove surfaces and convex surfaces.

9. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The three-dimensional detection mechanism (2) is equipped with an electrically controlled telescopic device (205), and a scanning device (207) is fixed to the telescopic end of the electrically controlled telescopic device (205) via an electrically controlled pan-tilt platform (206); The model structure analysis also includes: Step 2.1: According to the deep hole position, control the scanning distance measuring device (2073) to move to the deep hole position; Step 2.2: obtaining a plurality of deep hole depth measurement data by adjusting the orientation of the scanning distance measuring device (2073) relative to the deep hole; Step 2.3 Use the deepest depth measurement data to correct the original deep hole depth data H m-c , get the corrected data H m-c `.

10. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The scanning device (207) further comprises: an infrared temperature measuring device (2074); the control system comprises: a drying process analysis module, the module acquiring the measurement quantity of the infrared temperature measuring device (2074) to perform drying process analysis to determine whether the ceramic shell (4) to be dried has been dried; The drying process analysis includes: regularly or continuously measuring the internal temperature T of the deep hole; v - Curve Q of drying time t v , when Q v When all curve segments that conform to the preset curve rules appear, it indicates that the drying of the ceramic shell (4) to be dried is completed; wherein v is the natural number of all the deep holes of the ceramic shell (4) to be dried.

11. The method for preparing a ceramic shell for precision casting according to claim 10, characterized in that: The preset curve rule includes: the temperature T inside the deep hole gradually decreases from the initial drying temperature T1 to the temperature T2 as the drying time increases, and then gradually increases to the drying environment temperature T3 as the drying time increases. When the temperature T of the deep hole of the ceramic shell (4) to be dried experiences T1-T2-T3 and maintains the drying environment temperature T3 for a preset time U, it is judged that the drying is completed; the initial drying temperature T1 is 22-26°C, the temperature T2 is 5-7°C lower than the temperature T1, and the drying environment temperature T3 is 24±1°C.

12. The method for preparing a ceramic shell for precision casting according to claim 11, characterized in that: When there are multiple ceramic shells (4) to be dried in the same batch, the temperature of each deep hole of each ceramic shell (4) to be dried is detected one by one. When more than L% of the ceramic shells (4) to be dried are dried, it is determined that the drying of the entire batch of ceramic shells (4) to be dried is completed; the L%=(L g-d ) / (L 0-d )*100%, where L g-d is the number of ceramic shells (4) to be dried after drying in batch d, L 0-d is the number of all ceramic shells (4) to be dried in batch d; wherein the value of L% is: 100%≥L%≥E%; wherein E is the preset threshold value of the minimum drying completion percentage of all ceramic shells (4) to be dried in batch d.

13. The method for preparing a ceramic shell for precision casting according to claim 12, characterized in that: The fan group control analysis includes: For all the fan units p facing the ceramic shell (4) to be dried with deep holes on its surface, the following method is adopted: Step 3.1 Obtain the total number of deep holes D0 of the ceramic shell (4) to be dried, and obtain the total number of deep holes D0 on the surface of the ceramic shell (4) to be dried facing the fan unit p. p ; said p is the number of the fan units arranged on different sides of the vacuum drying chamber (1); Step 3.2 Calculate k S-p % = D p / D0*100%, k S-p % is the control parameter of fan group p; Step 3.3 Repeat steps 3.1 to 3.2 to obtain k of all fan groups S-p %; For all the fan units P facing the ceramic shell (4) to be dried without deep holes on its surface, the following method is adopted: Calculate k F-p % = [1-D0 / (D0+1)] * 100%, the k F-p % is the control parameter of fan group p; The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

14. The method for preparing a ceramic shell for precision casting according to claim 12, characterized in that: The fan group control analysis includes: For all the fan units p facing the ceramic shell (4) to be dried with deep holes on its surface, the following method is adopted: Step 4.1 Obtain the total number of deep holes D0 of the ceramic shell (4) to be dried, and obtain the total number of deep holes D0 on the surface of the ceramic shell (4) to be dried facing the fan unit p. p ; said p is the number of the fan units arranged on different sides of the vacuum drying chamber (1); Step 4.2 According to D0 and D p The number of k is obtained from the control parameter database S-p %; the k S-p % is the control parameter of fan group p; Step 4.3 Repeat steps 4.1 to 4.2 until k of all fan groups is obtained. S-p %; For all the fan units P facing the ceramic shell (4) to be dried without deep holes on its surface, the following method is adopted: According to the total number D0 of all deep holes in the ceramic shell (4) to be dried, k is obtained from the control parameter database. F-p %; the k F-p % is the control parameter of fan group p; The fan group control module obtains the k of all fan groups S-p % and k F-p % is sent to the corresponding fan group p to control the fan group p to operate at full load k S-p % or k F-p % to run.

15. The method for preparing a ceramic shell for precision casting according to claim 14, characterized in that: Enter k into the control parameter database S-p % and k F-p % of the methods include: Step 5.1: simulating the same position and orientation of the fan unit as the target vacuum drying chamber (1) in the simulation device; Step 5.2 Preset different deep hole distribution conditions of the ceramic shell (4) to be dried for drying training, and determine the control parameter k of each fan group p when the relative full load corresponds to the optimal drying time under each deep hole distribution condition. S-p % and k F-p %; the deep hole distribution includes: the direction and number of the deep holes; the optimal drying time is the shortest time for the deep holes on each surface of the ceramic shell (4) to be dried and the surface layer to be dried synchronously; Step 5.3 Repeat step 5.2 until the deep hole distribution under normal conditions is trained and D0-D p —k S-p %—k F-p % of the deep hole-control parameter relationship group and store it in the control parameter database.

16. The method for preparing a ceramic shell for precision casting according to any one of claims 14 or 15, characterized in that: At least two fans are arranged and installed in the fan group; the fan group control module performs synchronous control or individual control on the fans in each fan group; 17. The method for preparing a ceramic shell for precision casting according to claim 16, characterized in that: The fan group control analysis also includes: Step 6.1 constructing a three-dimensional coordinate system based on a scanning starting point preset by the scanning device (207); Step 6.2: The scanning device (207) records the three-dimensional coordinate points in the space during the displacement process, and in the process of model structure analysis, the three-dimensional coordinate points are marked on the position, direction and depth of the deep hole of the ceramic shell (4) to be dried; Step 6.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p; Step 6.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up ; Step 6.5 Calculate k up-e % = (D up-e / D up )*k S-p %; The fan group control module obtains the k of each fan in the fan group p up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e %Run; for D up-e =0, the fan corresponding to runs at the lowest power.

18. The method for preparing a ceramic shell for precision casting according to claim 16, characterized in that: The fan group control analysis includes: Step 7.1 constructing a three-dimensional coordinate system based on a scanning starting point preset by the scanning device (207); Step 7.2: The scanning device (207) records the three-dimensional coordinate points in the space during the displacement process, and in the process of model structure analysis, the three-dimensional coordinate points are marked on the position, direction and depth of the deep hole of the ceramic shell (4) to be dried; Step 7.3 Obtain the coordinate system range U covered by the blowing direction of each fan in the fan group p p-e , where e is the natural number of the fan in fan group p; Step 7.4 Count U p-e Number of deep holes within the coverage area D up-e , and the number of deep holes D within the overall coverage of the fan group p up ; Step 7.5 According to D up and D up-e Get the k value of the corresponding fan from the control parameter database up-e %, the k up-e % is the control parameter of the fan numbered e in fan group p; The fan group control module obtains the k of each fan in the fan group p up-e % is sent to the corresponding fan to control the corresponding fan to fully load k up-e % to run.

19. The method for preparing a ceramic shell for precision casting according to claim 18, characterized in that: Enter k into the control parameter database up-e % of the methods include: Step 8.1: simulating the same position and orientation of the fan unit as the target vacuum drying chamber (1) in the simulation device; Step 8.2 Preset different deep hole distribution conditions of the ceramic shell (4) to be dried for drying training, and determine the operation ratio k of each fan in each fan group p when the fan is relatively fully loaded corresponding to the optimal drying time under each deep hole distribution condition. up-e %; the deep hole distribution includes: the direction and number of the deep holes; the optimal drying time is the shortest time for the deep holes on each surface of the ceramic shell (4) to be dried and the surface layer to be dried synchronously; Step 8.3 Repeat step 8.2 until the deep hole distribution under normal conditions is trained and D is constructed. up —D up-e —k up-e % of the deep hole-control parameter relationship group and store it in the control parameter database.

20. The method for preparing a ceramic shell for precision casting according to any one of claims 14 or 18, characterized in that: The vacuum rapid drying system comprises: a first data transmission module, a local database module and a remote system module; The first data transmission module is connected to the remote system module by signal connection via a signal line or a wireless network; The local database module is used as a control parameter database to store relevant deep hole-control parameter relationship groups and operation result data; The remote system module collects the deep hole-control parameter relationship group and operation result data of each vacuum rapid drying system through the first data transmission module, and selects the deep hole-control parameter relationship group corresponding to the best operation result from the same deep hole relationship; and based on authorization permission and / or instructions and / or automatic synchronization, the deep hole-control parameter relationship group corresponding to the best operation result is centralized through the remote system module and then synchronized to the local database module of each vacuum rapid drying system through the first data transmission module, or directly synchronized to the local database module of each vacuum rapid drying system through the first data transmission module; When the vacuum rapid drying system retrieves the deep hole-control parameter relationship group in the local database module, if there is a new optimal deep hole-control parameter relationship group, the new optimal deep hole-control parameter relationship group is preferentially retrieved.

21. The method for preparing a ceramic shell for precision casting according to claim 20, characterized in that: The vacuum rapid drying system also includes a second data transmission module; The remote system module is connected to the control system signal of the vacuum rapid drying system by a signal line connection or a wireless network connection through the second data transmission module, so as to send remote control instructions to the control system and / or obtain control instructions issued by the control system and / or obtain various electrical instructions in the vacuum rapid drying system. Control the operating status parameters of the equipment; The execution priority of the remote control instruction issued by the remote system module is higher than the execution priority of the control instruction issued by the control system.

22. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The scanning device (207) comprises: a thermal imager (2072); the method for making the drying time of all parts of the ceramic shell to be dried tend to be consistent comprises: Step 9.1: During the drying process of the ceramic shell (4) to be dried, the thermal imager (2072) and the scanning device (207) take real-time thermal imaging photos of the ceramic shell (4) to be dried, and send the photos to the control system; Step 9.2 The control system determines whether there is an area T with a high and low temperature difference exceeding a preset temperature difference threshold value according to the heat distribution in the thermal imaging image when the drying time exceeds the preset first drying time. If there is an area T, the following determination and operation are performed: When the low temperature area temperature of area T is lower than the preset low temperature threshold, the operating power of the fan group corresponding to area T is reduced; When the high temperature area temperature of area T is higher than the preset high temperature threshold, the operating power of the fan group corresponding to area T is increased; When the existence time of area T exceeds the preset time threshold, and the temperature of the low temperature area of ​​area T is higher than the preset low temperature threshold, and the temperature of the high temperature area of ​​area T is lower than the preset high temperature threshold, the operating power of the fan group corresponding to area T is increased.

23. The method for preparing a ceramic shell for precision casting according to claim 22, characterized in that: The preset low temperature threshold is 12-15° C., the preset high temperature threshold is 26-28° C., the preset first drying time is 1-3 minutes, and the preset time threshold is 30-60 seconds.

24. The method for preparing a ceramic shell for precision casting according to claim 1, characterized in that: The method for vacuum rapid drying treatment comprises: When drying the surface layer: first, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 750-720 mmHg within 5 seconds; then the vacuum degree of the ceramic shell to be dried is restored from 750-720 mmHg to normal pressure within 5 seconds; the above process is repeated until the surface layer is dried; When drying the transition layer: first, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 720-680 mmHg within 7 seconds; then the vacuum degree of the ceramic shell to be dried is restored from 720-680 mmHg to normal pressure within 7 seconds; the above process is repeated until the transition layer is dried; When drying the support layer, the following steps are included: Step 10.1: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 260-20 mmHg within 30 seconds; Step 10.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes; Step 10.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds; Step 10.4: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 260-20 mmHg within 30 seconds; Step 10.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds; Step 10.6: Repeat steps 10.4 and 10.5 until the support layer is completely dried; When drying the sealing layer: first, the vacuum degree of the ceramic shell to be dried is reduced from normal pressure to 120-90 mmHg within 40 seconds; then the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 120 seconds; the above process is repeated until the sealing layer is dried.

25. The method for preparing a ceramic shell for precision casting according to claim 24, characterized in that: The support layer is provided with at least three layers from the transition layer to the sealing layer, wherein: The inner surface of the first layer of the support layer is attached to the outer surface of the transition layer, and the vacuum rapid drying process of the first layer of the support layer includes the following steps: Step 11.1: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 260-220 mmHg within 30 seconds; Step 11.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes; Step 11.3 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 40 seconds; Step 11.4: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 260-220 mmHg within 30 seconds; Step 11.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 40 seconds; Step 11.6 Repeat steps 11.4 and 11.5 until the first layer of the support layer is dried; The inner surface of the second support layer is attached to the outer surface of the first support layer, and the vacuum rapid drying process of the second support layer is performed, including the following steps: Step 12.1: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 200-150 mmHg within 30 seconds; Step 12.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes; Step 12.3: The vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds; Step 12.4: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 200-150 mmHg within 30 seconds; Step 12.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 60 seconds; Step 12.6 Repeat steps 12.4 and 12.5 until the second layer of the support layer is dried; The inner surface of the third layer of the support layer is attached to the outer surface of the second layer of the support layer, and the vacuum rapid drying process of the third layer of the support layer is performed, including the following steps: Step 13.1: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds; Step 13.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes; Step 13.3: The vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds; Step 13.4: reducing the vacuum degree of the ceramic shell to be dried from normal pressure to 80-20 mmHg within 30 seconds; Step 13.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds; Step 13.6 Repeat steps 13.4 and 13.5 until the third layer of the support layer is dried; The inner surface of the sealing layer is in contact with the outer surface of the third layer of the supporting layer.

26. The method for preparing a ceramic shell for precision casting according to claim 2, characterized in that: The vacuum rapid drying system further comprises: a vacuum tank (5); one end of the vacuum tank (5) is connected to a vacuum pump (8) via a second connecting pipe, and a third electrically controlled valve (9) is provided on the second connecting pipe; the other end of the vacuum tank (5) is connected to a vacuum drying chamber (1) via a third connecting pipe (7), and a fourth electrically controlled valve (6) is provided on the third connecting pipe (7).

27. The method for preparing a ceramic shell for precision casting according to claim 26, characterized in that: When vacuum drying is performed on the support layer and the sealing layer, an instantaneous pressure reduction operation is also included; the instantaneous pressure reduction operation includes: First, before reducing the pressure, the fourth electric control valve (6) is closed, and the vacuum tank (5) is evacuated to a low vacuum state in advance; Then, when the pressure is reduced, the fourth electrically controlled valve (6) is opened, so that the vacuum drying chamber (1) is connected to the vacuum tank (5), and the pressure is instantly reduced to a balanced low pressure within 0.5 seconds; Finally, the vacuum pump (8) simultaneously extracts the gaseous components in the vacuum tank (5) and the vacuum drying chamber (1), and after the vacuum degree in the vacuum drying chamber (1) meets the preset target, the fourth electrically controlled valve (6) and the first electrically controlled switch valve (10) are closed, and at the same time, the vacuum pump (8) continues to extract the gaseous components in the vacuum tank (5) into the vacuum tank (5) to a low vacuum state.

28. The method for preparing a ceramic shell for precision casting according to claim 27, characterized in that: The vacuum drying of the support layer and the sealing layer also includes the instantaneous depressurization operation: The first layer of the support layer is vacuum-dried quickly, and the following steps are included: Step 14.1: perform an instantaneous pressure reduction operation, and reduce the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank (5) maintains vacuum; Step 14.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank (5); Step 14.3: The vacuum degree of the ceramic shell to be dried is restored to normal pressure within 40 seconds, and the vacuum tank (5) continues to be evacuated; Step 14.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 10 seconds, while the vacuum tank (5) maintains vacuum; Step 14.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 40 seconds, and the vacuum tank (5) continues to be evacuated; Step 14.6 Repeat steps 14.4 and 14.5 until the first layer of the support layer is dried; The vacuum rapid drying process of the second layer of the support layer includes the following steps: Step 15.1: perform an instantaneous pressure reduction operation, and reduce the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank (5) maintains vacuum; Step 15.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank (5); Step 15.3: The vacuum degree of the ceramic shell to be dried is restored to normal pressure within 60 seconds, and the vacuum tank (5) continues to be evacuated; Step 15.4 performs an instantaneous pressure reduction operation, and reduces the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 200-150 mmHg within 15 seconds, while the vacuum tank (5) maintains vacuum; Step 15.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 60 seconds, and the vacuum tank (5) continues to be evacuated; Step 15.6: Repeat steps 15.4 and 15.5 until the second layer of the support layer is dried; The vacuum rapid drying process of the third layer of the support layer includes the following steps: Step 16.1: perform an instantaneous pressure reduction operation, and reduce the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank (5) maintains vacuum; Step 16.2: Maintain the vacuum degree of the ceramic shell to be dried in a negative pressure state for 4-6 minutes, and continue to evacuate the vacuum tank (5); Step 16.3: The vacuum degree of the ceramic shell to be dried is restored to normal pressure within 90 seconds, and the vacuum tank (5) continues to be evacuated; Step 16.4: perform an instantaneous pressure reduction operation, and reduce the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 80-20 mmHg within 25 seconds, while the vacuum tank (5) maintains vacuum; Step 16.5 allows the vacuum degree of the ceramic shell to be dried to return to normal pressure within 90 seconds, and the vacuum tank (5) continues to be evacuated; Step 16.6 Repeat steps 16.4 and 16.5 until the third layer of the support layer is dried; The vacuum rapid drying process of the sealing layer includes the following steps: Step 17.1: perform an instantaneous pressure reduction operation, and reduce the vacuum degree of the ceramic shell environment to be dried from the instantaneous equilibrium low pressure to 260-220 mmHg within 35 seconds, while the vacuum tank (5) maintains vacuum; Step 17.2: the vacuum degree of the ceramic shell to be dried is restored to normal pressure within 120 seconds, and the vacuum tank (5) continues to be evacuated; Step 17.3 Repeat steps 17.1 and 17.2 until the sealing layer is completely dry.

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