Preparation method and application of lead-tungsten alloy, collimator forming method and mold device

Abstract

The present invention discloses a lead-tungsten alloy preparation method and application, a collimator forming method, and a mold device. The method comprises the following steps: screening tungsten powder with a particle size within a specific threshold range; melting pure lead in a furnace to obtain a lead melt, and then further setting the furnace temperature; adding the screened tungsten powder and a flux to the furnace, mixing them with the lead melt, and smelting them to form a lead-tungsten alloy melt; and treating the lead slag and waste smoke generated during the smelting process. This method solves the technical problem that the existing 3D printing-produced back-collimator is prone to fine sintered particle gaps, which can cause the back-collimator to be easily damaged and fractured, thus affecting medical efficiency and cost-effectiveness.

Description

Technical Field

[0001] The present invention relates to the technical field of materials for medical CT, and in particular to a preparation method and application of a lead-tungsten alloy, a collimator forming method and a mold device. Background Art

[0002] With advancements in medical device technology, the back-scaling (ASG) used in medical CT systems has evolved from the original one-dimensional back-scaling to today's two-dimensional back-scaling. One-dimensional back-scaling is typically made by bonding a tungsten sheet to a back-scaling base. However, bonding a two-dimensional back-scaling using this method is difficult and lacks guaranteed accuracy. Therefore, two-dimensional back-scaling is typically manufactured using tungsten powder 3D printing.

[0003] Due to the characteristics of pure tungsten material and the limitations of the 3D printing process, when observed under a microscope, the 3D-printed post-collimator will show that it is composed of a stack of tiny sintered particles. There are gaps between the tiny sintered particles that cannot contact each other, which makes the processed post-collimator extremely easy to damage and break, affecting medical efficiency. In addition, the tungsten material itself and the processing technology are relatively expensive, and damage can easily cause unnecessary economic losses.

[0004] Therefore, there is an urgent need for a material that can replace pure tungsten and a molding method that can replace 3D printing. Summary of the Invention

[0005] To this end, the present invention provides a lead-tungsten alloy preparation method and use, a collimator molding method and a mold device, so as to solve the technical problem in the prior art that the back collimator obtained by 3D printing is prone to the presence of small sintered particle gaps, which causes the back collimator to be easily damaged and broken, affecting medical efficiency and economy.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a lead-tungsten alloy comprises the following steps:

[0008] Screening tungsten powder with particle size within a specific threshold range;

[0009] Pure lead is placed in a furnace to melt to obtain molten lead, and then the furnace temperature is further set;

[0010] The screened tungsten powder and flux are added to the furnace respectively, mixed with the lead melt, and a lead-tungsten alloy melt is formed through a smelting process;

[0011] Treatment of lead slag and waste smoke generated during the smelting process.

[0012] On the basis of the above technical solution, the present invention is further described as follows:

[0013] As a further embodiment of the present invention, the screening of tungsten powder having a particle size within a specific threshold range specifically includes:

[0014] Tungsten powder selection: screen tungsten powder with a particle size of 10 to 15 μm in diameter, deoxidize the screened tungsten powder, and then preheat the deoxidized tungsten powder.

[0015] As a further embodiment of the present invention, the step of melting pure lead in a furnace to obtain molten lead and then further setting the furnace temperature specifically includes:

[0016] Pure lead is placed in a furnace for melting to obtain lead melt, and then the furnace temperature is further set to 1000-1200℃, and the lead dust generated during the melting process is treated.

[0017] As a further embodiment of the present invention, the screened tungsten powder and the flux are added to a furnace respectively, mixed with the lead melt, and smelted to form a lead-tungsten alloy melt, specifically comprising:

[0018] The deoxidized and preheated tungsten powder is further added to the melting furnace with a solvent, and then stirred as a whole to completely mix the tungsten powder into the lead melt. It is melted at a set furnace temperature of 1000-1200℃ to form a lead-tungsten alloy melt. The furnace temperature is then further increased to 1400-1500℃ to accelerate the flow of the lead-tungsten alloy melt, and finally a standard lead-tungsten alloy melt is obtained.

[0019] As a further embodiment of the present invention, the treatment of lead slag and waste smoke generated during the smelting process specifically includes:

[0020] Lead slag and waste smoke are two types of waste produced during the smelting process of lead-tungsten alloy. The lead slag is further treated at high temperature to separate into crude lead and waste slag.

[0021] The crude lead is put back into the furnace for secondary use, and the waste slag is treated harmlessly;

[0022] The waste smoke is separated into solid particles and waste gas through a cyclone separator. The solid particles are separated and disposed of harmlessly together with the waste residue; the waste gas passes through a purification device and is discharged into the atmosphere after meeting environmental protection requirements.

[0023] A use of the lead-tungsten alloy prepared according to the lead-tungsten alloy preparation method is used to make a formed ASG rear collimator.

[0024] A method for forming a collimator for use with the lead-tungsten alloy comprises the following steps:

[0025] Pour the standard lead-tungsten alloy melt into the forming mold of the ASG rear collimator;

[0026] After cooling, the mold is removed and the final processing of the ASG post-collimator is carried out.

[0027] As a further embodiment of the present invention, the step of casting the standard lead-tungsten alloy melt into the forming mold of the ASG rear collimator specifically includes:

[0028] The standard lead-tungsten alloy melt is poured into the forming die of the ASG rear collimator through the die-casting machine and the pressure is maintained for 1 minute;

[0029] The high-frequency heating coil installed on the outer side of the ASG rear collimator forming mold is activated, and the high-frequency heating coil is used to preheat the ASG rear collimator forming mold to maintain the ASG rear collimator forming mold to a predetermined difference range of 350°C. Then, the liquid lead-tungsten alloy melt is poured into the ASG rear collimator forming mold through a die-casting machine, and the pressure is maintained for 1 minute. After the inner cavity of the forming mold is completely filled, it begins to naturally cool to room temperature.

[0030] As a further solution of the present invention, the demoulding after cooling and the final processing of the ASG post-collimator specifically include:

[0031] The standard lead-tungsten alloy melt in the ASG rear collimator forming mold is demolded after cooling;

[0032] The specific demoulding process is:

[0033] Taking advantage of the different thermal expansion coefficients of different materials, the mold is first frozen at -40°C and then heated to 250°C to form a natural gap between the molding mold and the ASG rear collimator, and then demolding is performed;

[0034] Perform post-processing of ASG collimator, including appearance polishing, finishing, and dimensional inspection;

[0035] The ASG rear collimator forming mold is placed in a sealed cabin, and then an insulation cover is installed to surround the outer side of the sealed cabin. A cooling pipe is connected to the interior of the sealed cabin, and liquid nitrogen is filled into the cooling pipe to force the ASG rear collimator forming mold to cool down to below -60°C. After the temperature stabilizes, the insulation cover is removed, and the high-frequency heating coil installed on the outer side of the ASG rear collimator forming mold is activated again to heat the ASG rear collimator forming mold to above 250°C. This creates a temperature difference of more than 300°C in the ASG rear collimator forming mold in a short period of time. The principle of thermal expansion and contraction is used to naturally separate the ASG rear collimator from the core mold of the forming mold, and finally the ASG rear collimator is successfully demolded.

[0036] A mold device for performing the collimator forming method, comprising:

[0037] Support frame control structure, forming mold and insulation cover;

[0038] The support frame regulating structure includes a support platform bracket, a casting bucket, a cooling pipe, a high-frequency heating coil, a mold positioning plate and a sealed cabin;

[0039] The casting hopper is fixedly provided on the top of the pedestal support, and the mold positioning plate is fixedly provided on the bottom of the pedestal support. The mold positioning plate is provided corresponding to the casting hopper, and the mold positioning plate has a conveying channel connected to the casting hopper.

[0040] The sealed cabin is fixedly arranged at the bottom position of the support platform, and the sealed cabin is correspondingly located at the outer side of the mold positioning plate and the forming mold;

[0041] The cooling pipe is connected between the top of the support platform and the interior of the sealed cabin, and the cooling pipe serves as an input channel for liquid nitrogen to assist in cooling the forming mold;

[0042] The high-frequency heating coil is fixedly arranged at the bottom position of the support platform bracket, and the high-frequency heating coil is correspondingly located at the outer side of the sealed cabin to assist in heating the forming mold;

[0043] The forming mold includes a bottom mold and a top mold that are detachably fixedly connected and a core mold that is fixedly set on the bottom mold;

[0044] The top of the top mold is also connected to a base interface end, and the top mold is connected to the mold positioning plate through a corresponding detachable fixed assembly between the base interface end and the mold positioning plate;

[0045] The heat-insulating cover is detachably mounted on the sealed cabin.

[0046] The present invention has the following beneficial effects:

[0047] 1. The lead-tungsten alloy prepared by the present invention is a new material with the characteristics of high density, high strength and good toughness. It can replace the existing pure tungsten as the latest printing material;

[0048] 2. The lead-tungsten alloy prepared by the present invention can solve the problem of brittle cracking and fragility of 3D printed post-collimators;

[0049] 3. The molding process for preparing lead-tungsten alloy of the present invention has the characteristics of low cost and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0051] Figure 1 A schematic diagram of the overall process structure of the lead-tungsten alloy preparation method provided in an embodiment of the present invention.

[0052] Figure 2 Schematic diagram of the material preparation principle of the lead-tungsten alloy preparation method provided in an embodiment of the present invention.

[0053] Figure 3 This is a schematic diagram of the overall exploded structure of the collimator forming mold device provided by an embodiment of the present invention.

[0054] Figure 4 This is a schematic diagram of the assembly structure of the support regulating structure corresponding to one side direction in the collimator forming mold device provided by an embodiment of the present invention.

[0055] Figure 5 This is a schematic diagram of the assembly structure of the support regulating structure corresponding to the other side direction in the collimator forming mold device provided by an embodiment of the present invention.

[0056] Figure 6 This is a schematic diagram of the exploded structure of the forming mold in the collimator forming mold device provided by an embodiment of the present invention.

[0057] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0058] Support frame control structure 1: support platform 11, casting bucket 12, cooling pipe 13, high-frequency heating coil 14, mold positioning plate 15, sealing cabin 16;

[0059] Forming mold 2: bottom mold 21, top mold 22, core mold 23, ASG rear collimator 24, and support platform interface end 25;

[0060] Insulation cover 3. DETAILED DESCRIPTION

[0061] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0062] The terms "upper", "lower", "left", "right", "middle", etc. used in this specification are only for the convenience of description and are not intended to limit the scope of the present invention. Changes or adjustments to their relative relationships should be regarded as within the scope of the present invention without substantially changing the technical content.

[0063] like Figure 1 and Figure 2 As shown, the embodiment of the present invention provides a method for preparing a lead-tungsten alloy, wherein metal lead and metal tungsten are smelted in the presence of a flux to form a new lead-tungsten alloy material. The lead-tungsten alloy material has both the rigidity of tungsten and the toughness of lead. At the same time, since the melting point of lead is only 327°C, the boiling point of lead is 1740°C, and the melting point of tungsten is 3410°C, the state of the lead-tungsten alloy material is actually a material after the gaps between solid tungsten particles are filled with liquid lead water and solidified (please refer to Figure 2 ), with tungsten as the main alloy material and lead as the binder of the alloy material. The two complement each other, taking into account both rigidity and toughness, and achieving radiation isolation with high density. The specific steps include:

[0064] S1: Screening tungsten powder with particle size within a specific threshold range;

[0065] The specific process is as follows: tungsten powder selection, screening tungsten powder with a particle size of 10-15μm in diameter, deoxidation treatment of the screened tungsten powder, and then preheating the deoxidized tungsten powder;

[0066] S2: pure lead is placed in a furnace to melt to obtain lead melt, and then the furnace temperature is further set;

[0067] The specific process is as follows: pure lead is placed in a furnace for melting to obtain lead melt, and then the furnace temperature is further set to 1000-1200℃, and the lead dust generated during the melting process is processed;

[0068] S3: Add the screened tungsten powder and flux into the furnace respectively, mix with the lead melt, and form a lead-tungsten alloy melt through a smelting process;

[0069] The specific process is as follows: deoxidized and preheated tungsten powder is further added to the melting furnace with a solvent, and then the whole is stirred to ensure that the tungsten powder is completely mixed with the lead melt. The lead-tungsten alloy melt is formed at a set furnace temperature of 1000-1200℃. The furnace temperature is then further increased to 1400-1500℃ to accelerate the flow of the lead-tungsten alloy melt, and finally a standard lead-tungsten alloy melt is obtained.

[0070] S4: Treatment of lead slag and waste smoke generated during the smelting process;

[0071] The specific process is as follows: the lead slag and waste smoke are generated during the smelting process of lead-tungsten alloy; the lead slag is further treated at high temperature to separate into crude lead and waste slag;

[0072] The crude lead is put back into the furnace for secondary use, and the waste slag is treated harmlessly;

[0073] The waste smoke is separated into solid particles and waste gas through a cyclone separator. The solid particles are separated and disposed of harmlessly together with the waste residue; the waste gas passes through a purification device and is discharged into the atmosphere after meeting environmental protection requirements.

[0074] The lead-tungsten alloy melt prepared by the above method is further used to make a formed ASG rear collimator.

[0075] The embodiment of the present invention further provides a collimator forming method, which specifically includes the following steps:

[0076] S1: pouring the standard lead-tungsten alloy melt into the forming mold of the ASG rear collimator;

[0077] The specific process is as follows: standard lead-tungsten alloy melt is poured into the forming die of the ASG rear collimator through a die-casting machine, and the pressure is maintained for 1 minute;

[0078] More specifically, a high-frequency heating coil mounted on the outer side of the ASG rear collimator forming die is activated to preheat the ASG rear collimator forming die using the high-frequency heating coil, maintaining the ASG rear collimator forming die at a predetermined temperature of 350°C. Liquid lead-tungsten alloy melt is then poured into the ASG rear collimator forming die through a die-casting machine, and the pressure is maintained for 1 minute. After the inner cavity of the forming die is completely filled, the temperature begins to naturally cool to room temperature.

[0079] S2: After cooling, demoulding is performed and the final processing of the ASG post-collimator is performed.

[0080] The specific process is as follows: the standard lead-tungsten alloy melt in the ASG post-collimator forming mold is cooled and then demolded;

[0081] The specific demoulding process is:

[0082] Taking advantage of the different thermal expansion coefficients of different materials, the mold is first frozen at -40°C and then heated to 250°C to form a natural gap between the molding mold and the ASG rear collimator, and then demolding is performed;

[0083] Perform post-processing of ASG collimator, including appearance polishing, finishing, and dimensional inspection;

[0084] More specifically, the ASG rear collimator forming mold is placed in a sealed cabin, and then an insulation cover is installed to surround the outer side of the sealed cabin. A cooling pipe is connected to the interior of the sealed cabin, and liquid nitrogen is filled in the cooling pipe to force the ASG rear collimator forming mold to cool down to below -60°C. After the temperature stabilizes, the insulation cover is removed, and the high-frequency heating coil installed on the outer side of the ASG rear collimator forming mold is activated again to heat the ASG rear collimator forming mold to above 250°C. This allows the ASG rear collimator forming mold to generate a temperature difference of more than 300°C in a short period of time. The principle of thermal expansion and contraction is used to naturally separate the ASG rear collimator from the core mold of the forming mold, and finally the ASG rear collimator is successfully demolded.

[0085] like Figures 3 to 6 As shown, the embodiment of the present invention also provides a mold device for executing the collimator forming method, including a support regulating structure 1, a forming mold 2 and a heat-insulating cover 3, so as to effectively realize the integrated material infusion, forming and temperature control functions of the ASG rear collimator. The specific settings are as follows:

[0086] Please refer to Figures 3 to 5 The support frame regulating structure 1 includes a support platform bracket 11, a casting bucket 12, a cooling pipe 13, a high-frequency heating coil 14, a mold positioning plate 15 and a sealed cabin 16; wherein, the casting bucket 12 is fixedly provided on the top of the support platform bracket 11, and the mold positioning plate 15 is fixedly provided on the bottom of the support platform bracket 11, the mold positioning plate 15 and the casting bucket 12 are arranged correspondingly, and the mold positioning plate 15 has a conveying channel connected to the casting bucket 12, which is used to effectively serve as the assembly positioning basis of the forming mold 2 through the mold positioning plate 15, and enables the lead-tungsten alloy melt poured into the casting bucket 12 to reach the forming mold 2 through the conveying channel of the mold positioning plate 15.

[0087] The sealed cabin 16 is fixedly provided at the bottom position of the support bracket 11, and the sealed cabin 16 is correspondingly located at the outer side of the mold positioning plate 15 and the forming mold 2; the cooling pipe 13 is connected between the top position of the support bracket 11 and the interior of the sealed cabin 16, and is used as an input channel for liquid nitrogen through the cooling pipe 13 to assist in cooling the forming mold 2; the high-frequency heating coil 14 is fixedly provided at the bottom position of the support bracket 11, and the high-frequency heating coil 14 is correspondingly located at the outer side of the sealed cabin 16 to assist in heating the forming mold 2.

[0088] Please refer to Figure 3 and Figure 6 The molding mold 2 includes a bottom mold 21 and a top mold 22 that are detachably fixedly connected and a core mold 23 fixedly set on the bottom mold 21, so as to complete the post-injection molding of the ASG rear collimator 24 through the molding mold 2; the top of the top mold 22 is also connected to a base interface end 25, and the top mold 22 is detachably fixedly assembled with the mold positioning plate 15 through the base interface end 25; so as to realize the positioning of the molding mold 2.

[0089] Please continue to refer to Figure 3 and Figure 5 The heat preservation cover 3 is detachably mounted on the sealed cabin 16 so as to cooperate with the sealed cabin 16 to perform low-temperature insulation when liquid nitrogen is filled in.

[0090] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for preparing a lead-tungsten alloy, characterized in that: The steps include: Screening tungsten powder with particle size within a specific threshold range; Pure lead is placed in a furnace to melt to obtain molten lead, and then the furnace temperature is further set; The screened tungsten powder and flux are added to the furnace respectively, mixed with the lead melt, and a lead-tungsten alloy melt is formed through a smelting process; Treatment of lead slag and waste smoke generated during the smelting process; The screening of tungsten powder having a particle size within a specific threshold range specifically includes: Tungsten powder selection: screening tungsten powder with a particle size of 10 to 15 μm in diameter, deoxidizing the screened tungsten powder, and then preheating the deoxidized tungsten powder; The process of placing pure lead in a furnace to melt to obtain molten lead and then further setting the furnace temperature specifically includes: Place pure lead in a furnace for melting to obtain lead melt, then further set the furnace temperature to 1000-1200℃ and treat the lead dust generated during the melting process; The screened tungsten powder and the flux are added to the furnace respectively, mixed with the lead melt, and smelted to form a lead-tungsten alloy melt, specifically comprising: The deoxidized and preheated tungsten powder is further added to the melting furnace with a solvent, and then stirred as a whole to completely mix the tungsten powder into the lead melt. It is melted at a set furnace temperature of 1000-1200℃ to form a lead-tungsten alloy melt. The furnace temperature is then further increased to 1400-1500℃ to accelerate the flow of the lead-tungsten alloy melt, and finally a standard lead-tungsten alloy melt is obtained.

2. The method for preparing lead-tungsten alloy according to claim 1, characterized in that: The treatment of lead slag and waste smoke generated during the smelting process specifically includes: Lead slag and waste smoke are two types of waste produced during the smelting process of lead-tungsten alloy. The lead slag is further treated at high temperature to separate into crude lead and waste slag. The crude lead is put back into the furnace for secondary use, and the waste slag is treated harmlessly; The waste smoke is separated into solid particles and waste gas through a cyclone separator. The solid particles are separated and disposed of harmlessly together with the waste residue; the waste gas passes through a purification device and is discharged into the atmosphere after meeting environmental protection requirements.

3. A use of the lead-tungsten alloy prepared according to the lead-tungsten alloy preparation method according to any one of claims 1-2, characterized in that: Used to make ASG post-collimator.

4. A method for forming a collimator for use with a lead-tungsten alloy according to claim 3, characterized in that: The steps include: Pour the standard lead-tungsten alloy melt into the forming mold of the ASG rear collimator; After cooling, demoulding is carried out and the final processing of the ASG post-collimator is carried out; The method of pouring the standard lead-tungsten alloy melt into the forming mold of the ASG rear collimator specifically includes: The standard lead-tungsten alloy melt is poured into the forming die of the ASG rear collimator through the die-casting machine and the pressure is maintained for 1 minute; The high-frequency heating coil installed on the outer side of the ASG rear collimator forming mold is activated to preheat the ASG rear collimator forming mold using the high-frequency heating coil to maintain the ASG rear collimator forming mold at a predetermined differential range of 350°C. Then, the liquid lead-tungsten alloy melt is poured into the ASG rear collimator forming mold through the die-casting machine and the pressure is maintained for 1 minute. After the inner cavity of the forming mold is completely filled, the temperature begins to naturally drop to room temperature. After cooling, demoulding is performed and the final processing of the ASG post-collimator is performed, which specifically includes: The standard lead-tungsten alloy melt in the ASG rear collimator forming mold is demolded after cooling; The specific demoulding process is: Taking advantage of the different thermal expansion coefficients of different materials, the mold is first frozen at -40°C and then heated to 250°C to form a natural gap between the molding mold and the ASG rear collimator, and then demolding is performed; Perform post-processing of ASG collimator, including appearance polishing, finishing, and dimensional inspection; The ASG rear collimator forming mold is placed in a sealed cabin, and then an insulation cover is installed to surround the outer side of the sealed cabin. A cooling pipe is connected to the interior of the sealed cabin, and liquid nitrogen is filled into the cooling pipe to force the ASG rear collimator forming mold to cool down to below -60°C. After the temperature stabilizes, the insulation cover is removed, and the high-frequency heating coil installed on the outer side of the ASG rear collimator forming mold is activated again to heat the ASG rear collimator forming mold to above 250°C. This creates a temperature difference of more than 300°C in the ASG rear collimator forming mold in a short period of time. Based on the principle of thermal expansion and contraction, the ASG rear collimator is naturally separated from the core mold of the forming mold, and finally the ASG rear collimator is successfully demolded.

5. A mold device for performing the collimator forming method according to claim 4, characterized in that: include: Support frame control structure, forming mold and insulation cover; The support frame regulating structure includes a support platform bracket, a casting bucket, a cooling pipe, a high-frequency heating coil, a mold positioning plate and a sealed cabin; The casting hopper is fixedly provided on the top of the pedestal support, and the mold positioning plate is fixedly provided on the bottom of the pedestal support. The mold positioning plate is provided corresponding to the casting hopper, and the mold positioning plate has a conveying channel connected to the casting hopper. The mold positioning plate serves as the assembly and positioning basis of the forming mold, and enables the lead-tungsten alloy melt poured into the casting hopper to reach the forming mold through the conveying channel of the mold positioning plate. The sealed cabin is fixedly arranged at the bottom position of the support platform, and the sealed cabin is correspondingly located at the outer side of the mold positioning plate and the forming mold; The cooling pipe is connected between the top of the support platform and the interior of the sealed cabin, and the cooling pipe serves as an input channel for liquid nitrogen to assist in cooling the forming mold; The high-frequency heating coil is fixedly arranged at the bottom position of the support platform bracket, and the high-frequency heating coil is correspondingly located at the outer side of the sealed cabin to assist in heating the forming mold; The molding die comprises a bottom die and a top die that are detachably fixedly connected and a core die that is fixedly connected to the bottom die; the ASG rear collimator is formed by pouring through the molding die; The top of the top mold is also connected to a base interface end, and the top mold is connected to the mold positioning plate through a corresponding detachable fixed assembly between the base interface end and the mold positioning plate to position the forming mold; The heat-insulating cover is detachably mounted on the sealed cabin, and the heat-insulating cover cooperates with the sealed cabin to perform low-temperature heat preservation when liquid nitrogen is filled.

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