Wax film manufacturing device and wax film manufacturing method

Abstract

The invention discloses a waxy film manufacturing device. The waxy film manufacturing device comprises a wax dipping area, a leveling area and a film forming area which are connected from bottom to top, wherein the wax dipping area is used for containing liquid-phase paraffin; a first heat insulation plate is arranged between the wax dipping area and the leveling area; a second heat insulation plate is arranged between the leveling area and the film forming area; a third heat insulation plate is arranged above the film forming area; the temperature of the wax dipping area, the leveling area and the film forming area is controlled independently; the temperature of the wax dipping area is 5-15 DEG C higher than the melting point of the liquid paraffin, the temperature of the leveling area is 5-10 DEG C higher than the temperature of the wax dipping area, and the temperature of the film forming area is 20-30 DEG C lower than the melting point of the liquid paraffin. According to the method, wax film manufacturing is divided into the three stages of wax dipping, leveling and film forming, the temperature of a wax dipping area, the temperature of a leveling area and the temperature of a film forming area are independently controlled, the mold lifting speed is increased to 1 mm / s or above from 0.1-1 mm / s of a traditional dip-coating technology, the technology control is more convenient and faster, and therefore the covering uniformity, the thickness accuracy and the roughness of a formed film are improved, and the precision requirement of precise injection molding is met.

Description

Technical Field

[0001] The invention relates to the technical field of wax film injection molding, and in particular to a wax film manufacturing device and a wax film manufacturing method. Background Art

[0002] Release agent is a functional substance between the mold and the finished product. It is coated on the mold surface to provide good surface smoothness and reduce adhesion. It can improve the mold release, alleviate mold release damage, and increase the reuse rate of the mold. It is widely used in injection molding process. Precision injection molding requires the dimensional accuracy of the molded blank to reach 0.01mm or less, especially the molding accuracy of semiconductor ceramic parts is usually at the micron level. Therefore, in addition to the need to use high-precision molds, the selection and coating accuracy of the release agent are required to be higher. Release agents are classified by active substances: wax series, siloxane (silicone oil, etc.) series, fluorine series, surfactant series, inorganic powder series, polyether series, etc. Among them, the wax series release agent is a mixture of several higher alkanes, insoluble in water, alcohol, acetone and other solvents, solid at room temperature, non-crystalline material, no fixed melting point, softening and plasticizing as the temperature rises until it melts. According to the source of wax raw materials, it can be divided into plant wax, animal wax, synthetic paraffin wax, microcrystalline wax, polyethylene wax, etc. Wax film is also commonly used as a multi-functional material for waterproofing, anti-corrosion, protection and packaging. In large-scale industrial applications, synthetic paraffin is cheap and widely used. The physical parameters of paraffin in the "Paraffin Product Manual" are shown in Table 1 below.

[0003] Table 1 Physical parameters of paraffin wax

[0004]

[0005]

[0006] In industrial applications, hot melt paraffin liquid is coated on the mold surface by spraying, smearing, wiping, dipping and other processes. However, spraying is only suitable for film formation on the outer surface of the mold, and the scope of application is limited. Smearing and wiping are unevenly formed. Dipping is suitable for the film formation of wax liquids for various special-shaped molds, and the scope of application is relatively wide. The Landau-Levich equation describes the relationship between the wet film thickness and the mold pulling speed. The equation considering the surface tension is as follows:

[0007]

[0008] Among them, H is the film thickness; c is the rheological constant of Newtonian fluid; η is the kinematic viscosity; v is the mold withdrawal speed; γ is the surface tension; ρ is the density; g is the gravity constant. Traditionally, after calculation, when the mold pulling speed is 0.1-1mm / s, the thickness of the paraffin film is about 10-20um. When the pulling speed is lower than 0.1mm / s, horizontal stripes ("coffee rings") perpendicular to the pulling direction are prone to appear. This is because when the pulling speed is too slow, the part pulled out of the liquid surface undergoes a solidification phase change, and the volume of the solidification front shrinks to form pores, causing capillary action. The wax liquid continues to replenish the solidification front in stages, and the density of the solidified part just pulled out of the liquid surface is always lower than the solidification front, resulting in uneven film density. When it is greater than 1mm / s, the wax liquid at the solidification front does not have time to solidify and flows downward due to its own gravity, which is prone to defects such as tears. However, the pulling speed window of 0.1 to 1 mm / s is too small and difficult to control. Its coverage uniformity, thickness accuracy, and roughness are difficult to control and cannot meet the accuracy requirements of precision injection molding.

[0009] In addition, in the ceramic slurry precision molding process, the injection molding material is ceramic slurry. During the injection molding process, due to the high injection pressure, the ceramic slurry severely erodes the mold wax film. If the wax solidification phase change process is not properly controlled, the resulting wax film will either have low hardness and strength, or be too brittle and easy to peel off from the mold, which will first affect the accuracy of the blank product, fail to demold, and cause damage to the mold. Summary of the invention

[0010] In view of the above problems in the prior art, the present invention provides a wax film production device and a wax film production method, which solves the problem that the existing wax film production cannot meet the accuracy requirements of precision injection molding.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] Provided is a wax film manufacturing device, comprising a wax immersion area, a leveling area and a film-forming area for containing liquid paraffin; a first heat insulation board is arranged between the wax immersion area and the leveling area; a second heat insulation board is arranged between the leveling area and the film-forming area; a third heat insulation board is arranged above the film-forming area; the wax immersion area, the leveling area and the film-forming area are temperature-controlled independently, the temperature of the wax immersion area is 5°C to 15°C higher than the melting point of the liquid paraffin, the temperature of the leveling area is 5°C to 10°C higher than the temperature of the wax immersion area, and the temperature of the film-forming area is 20°C to 30°C lower than the melting point of the liquid paraffin.

[0013] The present invention divides the wax film production into three stages: wax dipping, leveling, and film forming, and the wax dipping area, leveling area, and film forming area are independently temperature controlled, thereby increasing the mold pulling speed from 0.1 to 1 mm / s in the traditional dipping process to more than 1 mm / s, making the process control more convenient, thereby improving the coverage uniformity, thickness accuracy, and roughness of the film, and meeting the precision requirements of precision injection molding.

[0014] Furthermore, a central through hole is opened at the center of the first heat insulation board, the second heat insulation board and the third heat insulation board, and the diameter of the central through hole is 6mm to 8mm.

[0015] Furthermore, a central through hole is opened at the center of the first heat insulation board, the second heat insulation board and the third heat insulation board, and the diameter of the central through hole is 6mm to 8mm.

[0016] Furthermore, the outer sides of the wax impregnation area, the leveling area and the film-forming area are all covered with heat insulation cotton.

[0017] Furthermore, the liquid surface area of ​​the liquid phase paraffin in the wax immersion zone is larger than the cross-sectional area of ​​the wax film mold.

[0018] Furthermore, the liquid paraffin is semi-refined paraffin.

[0019] Another invention provides a method for making a wax film based on a wax film making device, which comprises the following steps:

[0020] Step S1, mold preparation: polish the surface of the wax film mold to make it smooth, and ultrasonically clean it 2 to 3 times;

[0021] Step S2, temperature setting: heating the wax immersion area, the leveling area and the film forming area respectively according to the melting point of the liquid paraffin;

[0022] Step S3, preheating the mold: separate the third insulation board and the second insulation board, pass the wax film mold prepared in step S1 through the central through holes of the third insulation board and the second insulation board and hoist it in the leveling area, then merge the third insulation board and the second insulation board, and preheat the wax film mold for 60 minutes to 120 minutes;

[0023] Step S4, wax dipping: after the wax film mold is preheated, the first insulation board is separated, and the preheated wax film mold is sent to the wax dipping area, so that the wax film mold is immersed below the wax liquid level of liquid paraffin, and the first insulation board is combined;

[0024] Step S5, leveling: separate the first heat insulation board, pull the wax film mold that has been dipped in wax to the leveling area at a uniform speed of 1-3 mm / s, and then merge the first heat insulation board for leveling, and the leveling time is 10 min to 20 min;

[0025] Step S6, film forming: separate the second heat insulation board, pull the wax film mold after leveling to the film forming area at a uniform speed of 5-10 mm / s, and combine the second heat insulation board to form the film.

[0026] Furthermore, in step S4, the wax immersion time of the metal wax film mold is 3 minutes to 5 minutes; the wax immersion time of the wax film mold with a porosity greater than 20% is 30 minutes to 50 minutes.

[0027] The present invention discloses a wax film manufacturing device and a wax film manufacturing method, and the beneficial effects are:

[0028] 1. The present invention divides the production of wax film into three stages: wax dipping, leveling, and film forming, and the wax dipping area, leveling area, and film forming area are independently temperature controlled, and the mold pulling speed is increased from 0.1 to 1 mm / s in the traditional dipping process to more than 1 mm / s, thereby increasing the window for the pulling speed, making the process control more convenient, and further improving the coverage uniformity, thickness accuracy, and roughness of the film, meeting the precision requirements of precision injection molding.

[0029] 2. In the present invention, the temperature of the wax immersion zone is set to be 5°C to 15°C higher than the melting point of paraffin wax, and the temperature of the leveling zone is set to be 5°C to 10°C higher than the temperature of the wax immersion zone. The leveling time is 10 to 20 minutes, so that the wax liquid can spread and adsorb evenly on the mold by its surface tension, effectively avoiding the wax liquid from forming wax film defects such as horizontal stripes ("coffee rings") and tear marks on the mold.

[0030] 3. The present invention pulls the wax film mold at a uniform speed of 5 to 10 mm / s to a film forming zone 20 to 30°C lower than the melting point of paraffin. Compared with the leveling zone, the temperature gradient is 30 to 55°C. The appropriate temperature gradient can make the wax liquid film on the mold enter the low temperature zone as a whole. The wax film has an appropriate crystallization rate, a small number of grains but a large particle size, rich crystal types, many crystal edges and angles, which are easy to connect with each other, a relatively dense structure, greater strength, and stronger toughness, which can effectively resist the mold filling scouring of the ceramic slurry. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of a wax film production device of the present invention.

[0032] Figure 2 It is a schematic internal cross-sectional view of a wax film production device of the present invention.

[0033] Among them, 1. wax immersion area; 2. leveling area; 3. film forming area; 4. first insulation board; 5. second insulation board; 6. third insulation board; 7. central through hole; 8. central through hole; 9. liquid paraffin. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0035] Example 1

[0036] This embodiment provides a wax film production device, the purpose of which is to solve the problem that the existing wax film production cannot meet the precision requirements of precision injection molding. Figure 1-Figure 2 , the specific structure of this embodiment will be described in detail below.

[0037] A wax film manufacturing device, comprising a wax immersion area 1 for containing liquid paraffin 9, a leveling area 2 and a film forming area 3 connected from bottom to top;

[0038] Among them, a first insulation board 4 is arranged between the wax immersion zone 1 and the leveling zone 2; a second insulation board 5 is arranged between the leveling zone 2 and the film forming zone 3; a third insulation board 6 is arranged above the film forming zone 3, and the wax immersion zone 1, the leveling zone 2 and the film forming zone 3 are independently temperature controlled. The temperature of the wax immersion zone 1 is 5℃~15℃ higher than the melting point of the liquid paraffin 9, the temperature of the leveling zone 2 is 5℃~10℃ higher than the temperature of the wax immersion zone 1, and the temperature of the film forming zone 3 is 20℃~30℃ lower than the melting point of the liquid paraffin 9.

[0039] In this embodiment, the wax impregnation area 1 is a box with an opening on the top, the leveling area 2 and the film-forming area 3 are through-boxes, and the liquid paraffin 9 is contained in the wax impregnation area 1. The liquid paraffin 9 is semi-refined paraffin. The wax impregnation area 1, the leveling area 2 and the film-forming area 3 are separated by the first insulation board 4 and the second insulation board 5 so that the wax impregnation area 1, the leveling area 2 and the film-forming area 3 can be independently heated and temperature controlled.

[0040] Since the wax used is a mixture of multiple higher alkanes and has no fixed melting point, the temperature of the wax immersion zone is 5°C to 15°C higher than the melting point of the commercially labeled liquid paraffin used, which can make the wax fully melted to be clear without turbidity;

[0041] The temperature of the leveling zone is 5℃~10℃ higher than that of the wax dipping zone, so that when the mold is pulled out of the wax liquid, there will be no coffee ring at the solidification front, and no tear marks will be left due to the influence of the pulling speed;

[0042] The temperature of the film-forming zone is 20°C to 30°C lower than the melting point of liquid paraffin, which allows a suitable temperature gradient to exist between the mold and the wax film, so that the wax film can be solidified and formed without peeling off due to excessive shrinkage of the mold.

[0043] Optionally, electric heating wires may be laid on the inner circumference of the wax immersion zone 1, the leveling zone 2 and the film forming zone 3, respectively, and then the wax immersion zone 1, the leveling zone 2 and the film forming zone 3 may be independently heated and temperature controlled through a temperature control switch.

[0044] Specifically, a central through hole 7 is opened at the center of the first insulation board 4, the second insulation board 5 and the third insulation board 6. The diameter of the central through hole 7 is 6mm to 8mm. The central through hole 7 is reserved to facilitate pulling the wax film mold through the central through hole 7, so that the wax film mold can be sent to the wax immersion area 1, the leveling area 2 and the film forming area 3 for pulling. The diameter of the central through hole 7 is 6mm to 8mm, which is convenient for controlling the pulling speed.

[0045] Specifically, the first insulation board 4, the second insulation board 5 and the third insulation board 6 are divided into two insulation sub-boards 8 along the central axis, and the two insulation sub-boards 8 can be separated from or merged to facilitate the passage of the wax film mold.

[0046] Specifically, the outer sides of the wax impregnation area 1, the leveling area 2 and the film-forming area 3 are all covered with heat-insulating cotton, and the heat-insulating cotton can be used to keep the wax impregnation area 1, the leveling area 2 and the film-forming area 3 warm, thereby reducing temperature loss.

[0047] Specifically, the liquid surface area of ​​the liquid paraffin 9 in the wax immersion zone 1 is larger than the cross-sectional area of ​​the wax film mold so that the wax film mold can be completely immersed in the liquid paraffin 9 in the wax immersion zone 1. In this embodiment, the liquid surface area of ​​the liquid paraffin 9 is more than 10 times larger than the cross-sectional area of ​​the wax film mold.

[0048] Example 2

[0049] Based on Example 1, this embodiment provides a wax film production method based on a wax film production device, the purpose of which is to solve the problem that the existing wax film production cannot meet the accuracy requirements of precision injection molding. This embodiment is to dip-coat 72# paraffin liquid on a graphite mold to produce a wax film. The specific production method in this embodiment will be described in detail below.

[0050] A wax film making method based on a wax film making device comprises the following steps:

[0051] Step S1, mold preparation: polish the surface of the wax film mold to be used until it is polished smooth, then use anhydrous ethanol to ultrasonically clean it for 5 minutes to 10 minutes and dry it, and repeat the ultrasonic cleaning 2 to 3 times.

[0052] Step S2, temperature setting: according to the melting point of the liquid paraffin 9, the wax immersion zone 1, the leveling zone 2 and the film forming zone 3 are heated respectively; wherein the temperature of the wax immersion zone 1 is 5°C to 15°C higher than the melting point of the liquid paraffin 9, the temperature of the leveling zone 2 is 5°C to 10°C higher than the temperature of the wax immersion zone 1, and the temperature of the film forming zone 3 is 20°C to 30°C lower than the melting point of the liquid paraffin 9.

[0053] In this embodiment, the liquid paraffin 9 is 72# paraffin liquid, and the melting point of 72# paraffin liquid is 72 +2 ℃, the temperature of wax immersion zone 1 is set to 87℃, the temperature of leveling zone 2 is set to 97℃, and the temperature of film forming zone 3 is set to 47℃. The wax immersion zone 1, leveling zone 2 and film forming zone 3 are heated respectively through the above temperature settings.

[0054] Step S3, mold preheating: separate the two insulation sub-boards 8 of the third insulation board 6 and the two insulation sub-boards 8 of the second insulation board 5, so that the wax film mold prepared in step S1 can be hoisted in the leveling area 2 through the central through hole 7 of the third insulation board 6 and the second insulation board 5, and then merge the two insulation sub-boards 8 of the third insulation board 6 and the two insulation sub-boards 8 of the second insulation board 5, so as to preheat the wax film mold, and the preheating time is 60min to 120min. In this embodiment, the preheating time is 60min.

[0055] Step S4, wax dipping: After the wax film mold is preheated, the two insulation sub-plates 8 of the first insulation board 4 are separated, and the preheated wax film mold is sent into the wax dipping area 1 through the central through hole 7 of the first insulation board 4, so that the wax film mold is immersed below the wax liquid level of the liquid paraffin 9, and the two insulation sub-plates 8 of the first insulation board 4 are merged.

[0056] In this embodiment, the wax film mold is a graphite mold, and the graphite mold is a wax film mold with a porosity greater than 20%. The wax immersion time of the wax film mold with a porosity greater than 20% is 30 minutes to 50 minutes. In this embodiment, the wax immersion time is 30 minutes.

[0057] Step S5, leveling: separate the two insulation sub-boards 8 of the first insulation board 4, pull the wax film mold that has been dipped in wax to the leveling area 2 at a uniform speed of 1 to 3 mm / s, and then merge the two insulation sub-boards 8 of the first insulation board 4 for leveling. The leveling time is 10 min to 20 min; in this embodiment, the leveling time is 10 min.

[0058] Step S6, film forming: separate the second heat insulation board 5, pull the wax film mold after leveling to the film forming area 3 at a uniform speed of 5-10 mm / s, and merge the second heat insulation board 5 to form a film.

[0059] Example 3

[0060] Based on Example 1, this embodiment provides a wax film production method based on a wax film production device, the purpose of which is to solve the problem that the existing wax film production cannot meet the accuracy requirements of precision injection molding. This embodiment is to dip-coat 60# paraffin liquid on an aluminum alloy mold to produce a wax film. The specific production method in this embodiment will be described in detail below.

[0061] A wax film making method based on a wax film making device comprises the following steps:

[0062] Step S1, mold preparation: polish the surface of the wax film mold to be used until it is polished smooth, then use anhydrous ethanol to ultrasonically clean it for 5 minutes to 10 minutes and dry it, and repeat the ultrasonic cleaning 2 to 3 times.

[0063] Step S2, temperature setting: according to the melting point of the liquid paraffin 9, the wax immersion zone 1, the leveling zone 2 and the film forming zone 3 are heated respectively; wherein the temperature of the wax immersion zone 1 is 5°C to 15°C higher than the melting point of the liquid paraffin 9, the temperature of the leveling zone 2 is 5°C to 10°C higher than the temperature of the wax immersion zone 1, and the temperature of the film forming zone 3 is 20°C to 30°C lower than the melting point of the liquid paraffin 9.

[0064] In this embodiment, the liquid paraffin 9 is 60# paraffin liquid, and the melting point of 60# paraffin liquid is 60 +2 ℃, the temperature of wax immersion zone 1 is set to 75℃, the temperature of leveling zone 2 is set to 85℃, and the temperature of film forming zone 3 is set to 40℃. The wax immersion zone 1, leveling zone 2 and film forming zone 3 are heated respectively through the above temperature settings.

[0065] Step S3, mold preheating: separate the two insulation sub-boards 8 of the third insulation board 6 and the two insulation sub-boards 8 of the second insulation board 5, so that the wax film mold prepared in step S1 can be hoisted in the leveling area 2 through the central through hole 7 of the third insulation board 6 and the second insulation board 5, and then merge the two insulation sub-boards 8 of the third insulation board 6 and the two insulation sub-boards 8 of the second insulation board 5, so as to preheat the wax film mold, and the preheating time is 60min-120min. In this embodiment, the preheating time is 120min.

[0066] Step S4, wax dipping: After the wax film mold is preheated, the two insulation sub-plates 8 of the first insulation board 4 are separated, and the preheated wax film mold is sent into the wax dipping area 1 through the central through hole 7 of the first insulation board 4, so that the wax film mold is immersed below the wax liquid level of the liquid paraffin 9, and the two insulation sub-plates 8 of the first insulation board 4 are merged.

[0067] In this embodiment, the wax film mold is an aluminum alloy mold, the aluminum alloy mold is a metal wax film mold, the wax immersion time of the metal wax film mold is 3 minutes to 5 minutes, and the wax immersion time in this embodiment is 3 minutes.

[0068] Step S5, leveling: separate the two insulation sub-boards 8 of the first insulation board 4, pull the wax film mold that has been dipped in wax to the leveling area 2 at a uniform speed of 1 to 3 mm / s, and then merge the two insulation sub-boards 8 of the first insulation board 4 for leveling. The leveling time is 10 min to 20 min; in this embodiment, the leveling time is 10 min.

[0069] Step S6, film forming: separate the second heat insulation board 5, pull the wax film mold after leveling to the film forming area 3 at a uniform speed of 5-10 mm / s, and merge the second heat insulation board 5 to form a film.

[0070] Although the specific implementation of the invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A wax film production device, characterized in that: The invention comprises a wax impregnation area (1) for containing liquid paraffin (9), a leveling area (2) and a film-forming area (3) connected from bottom to top; a first heat insulation board (4) is arranged between the wax impregnation area (1) and the leveling area (2); a second heat insulation board (5) is arranged between the leveling area (2) and the film-forming area (3); and a third heat insulation board (6) is arranged above the film-forming area (3); The wax immersion zone (1), leveling zone (2) and film-forming zone (3) are independently temperature-controlled; the temperature of the wax immersion zone (1) is 5°C to 15°C higher than the melting point of the liquid paraffin (9), the temperature of the leveling zone (2) is 5°C to 10°C higher than the temperature of the wax immersion zone (1), and the temperature of the film-forming zone (3) is 20°C to 30°C lower than the melting point of the liquid paraffin (9).

2. The wax film production device according to claim 1, characterized in that: A central through hole (7) is provided at the center of each of the first heat insulation board (4), the second heat insulation board (5) and the third heat insulation board (6), and the diameter of the central through hole (7) is 6 mm to 8 mm.

3. The wax film production device according to claim 1, characterized in that: The first heat insulation board (4), the second heat insulation board (5) and the third heat insulation board (6) are all divided into two heat insulation sub-boards (8) along the central axis.

4. The wax film production device according to claim 1, characterized in that: The outer sides of the wax impregnation area (1), the leveling area (2) and the film forming area (3) are all covered with heat insulation cotton.

5. The wax film making device according to claim 1, characterized in that: The liquid surface area of ​​the liquid phase paraffin (9) in the wax immersion zone (1) is larger than the cross-sectional area of ​​the wax film mold.

6. The wax film production device according to claim 1, characterized in that: The liquid paraffin (9) is semi-refined paraffin.

7. A method for producing a wax film based on the wax film producing device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, mold preparation: polish the surface of the wax film mold to make it smooth, and ultrasonically clean it 2 to 3 times; Step S2, temperature setting: heating the wax immersion area (1), the leveling area (2) and the film forming area (3) respectively according to the melting point of the liquid paraffin (9); Step S3, preheating the mold: separate the third insulation board (6) and the second insulation board (5), pass the wax film mold prepared in step S1 through the central through hole (7) of the third insulation board (6) and the second insulation board (5) and hoist it in the leveling area (2), then merge the third insulation board (6) and the second insulation board (5), and preheat the wax film mold for 60 minutes to 120 minutes; Step S4, wax dipping: after the wax film mold is preheated, the first insulation board (4) is separated, and the preheated wax film mold is sent to the wax dipping area (1), so that the wax film mold is immersed below the wax liquid level of the liquid phase paraffin (9), and the first insulation board (4) is merged; Step S5, leveling: separate the first heat insulation board (4), pull the wax film mold that has been dipped in wax to the leveling area (2) at a uniform speed of 1 to 3 mm / s, and then merge the first heat insulation board (4) for leveling, and the leveling time is 10 to 20 minutes; Step S6, film forming: separate the second heat insulation board (5), pull the wax film mold after leveling to the film forming area (3) at a uniform speed of 5 to 10 mm / s, and merge the second heat insulation board (5) to form a film.

8. The method for producing a wax film according to claim 7, characterized in that: In the step S4, the wax immersion time of the metal wax film mold is 3 minutes to 5 minutes; the wax immersion time of the wax film mold with a porosity greater than 20% is 30 minutes to 50 minutes.

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