Mold and thermoforming equipment for thermoforming IML film

Abstract

The present application provides a mold and a thermoforming device for the thermoforming of IML diaphragms. The upper mold of the mold includes an upper mold core. The bottom surface of the upper mold core is provided with two downwardly protruding and spaced-apart bending portions, so as to form a U-shaped first cavity between the two bending portions. The lower mold includes a base, a lower mold core, a placement platform and a lifting mechanism. The lower mold core has a second cavity with an upward opening, and there is a lifting channel between the bottom wall of the second cavity and the bottom surface of the lower mold core. The placement platform is used for placing the diaphragm and is located in the lifting channel. The lifting mechanism drives the placement platform to rise or fall. The diaphragm is thermoformed through the mold, effectively solving the problem of stretching and deformation of the patterns or characters on both sides of the diaphragm, and can protect the middle area of the diaphragm, reducing the occurrence of process defects such as scratches, deformation, and pitting, saving energy, and reducing the material cost of product layout.

Description

Technical Field

[0001] This application belongs to the technical field of IML process. More specifically, it relates to a mold and a thermoforming device for thermoforming IML film sheets. Background Art

[0002] PC+PMMA composite sheet is a composite material obtained by co-extrusion of two raw materials, polycarbonate (PC) and polymethyl methacrylate (PMMA). This composite sheet combines the advantages of high hardness and high wear resistance of PMMA material and the advantages of high toughness and good formability of PC material, and also has excellent light transmittance, with a transparent glass-like effect, and is widely used in electronic product casings, automotive interiors, wearable devices, smart furniture and other devices. PC+PMMA composite sheets are usually combined with the plastic surface by IML (In Molding Label) process to become a surface decoration protective film with characteristics such as wear resistance and scratch resistance.

[0003] The specific steps of the IML process are as follows: First, the PC+PMMA composite sheet is cut into film sheets of a predetermined shape and size; then, a layer with patterns or text is formed on the film sheet by printing, electroplating or other means according to the appearance effect of the product; then, the film sheet is formed into a 3D shape according to the product shape; after forming, the excess material at the edge of the film sheet is cut off; finally, the film sheet is placed in an injection mold for injection molding, so that the molten plastic raw material fills the mold and tightly combines with the film sheet to form the final product.

[0004] For film sheets made of PC+PMMA composite materials, 3D forming is usually carried out by high-pressure vacuum suction forming. However, this forming method has requirements for the position of the patterns or text on the film sheet. The patterns or text cannot be too close to the edge of the film sheet, otherwise they will be pulled and deformed, thus affecting the forming quality and reducing the production yield. Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a mold and a thermoforming device for thermoforming IML film sheets, so as to solve the technical problem that when 3D forming is carried out on PC+PMMA composite material film sheets by the method of high-pressure vacuum suction forming in the prior art, the patterns or text at the edge position will be stretched and deformed.

[0006] To achieve the above object, the technical solution adopted by this application is: to provide a mold for thermoforming an IML film, the mold including an upper mold and a lower mold. The upper mold includes an upper mold core, and the bottom surface of the upper mold core is provided with two downwardly protruding and spaced-apart bending portions, thereby forming a U-shaped first cavity between the two bending portions. The lower mold includes a base, a lower mold core, a placement platform, and a lifting mechanism. The lower mold core and the lifting mechanism are both installed on the base. The lower mold core has a second cavity with an upward opening, and there is a lifting channel between the bottom wall of the second cavity and the bottom surface of the lower mold core. The placement platform is used to place the film and is located in the lifting channel. The lifting mechanism drives the placement platform to rise so that the top surface of the placement platform is higher than the bottom wall of the second cavity, and third cavities are respectively formed between the top surface of the placement platform and the inner walls on both sides of the cavity. The placement platform matches the shape of the first cavity, and the bending portion matches the shape of the third cavity; or, the lifting mechanism drives the placement platform to descend so that the top surface of the placement platform and the bottom wall of the cavity are on the same plane.

[0007] In one embodiment, the lower mold core is made of graphene material, and the thermal conductivity of the lower mold core is greater than that of the placement platform.

[0008] In one embodiment, the upper mold core includes an intermediate block and two heating blocks. The two heating blocks are respectively fixedly attached to both sides of the intermediate block, and the two bending portions are respectively located at the bottoms of the two heating blocks; the two heating blocks are made of graphene material, and the thermal conductivity of the heating blocks is greater than that of the intermediate block.

[0009] In one embodiment, silica gel layers are respectively provided on the top surface of the placement platform and the bottom surface of the intermediate block.

[0010] In one embodiment, the placement platform is provided with a plurality of spaced-apart negative pressure channels so that the film can be adsorbed on the surface of the placement platform.

[0011] In one embodiment, the lower mold core has two boss portions, and the two boss portions are integrally extended upward from the two side edges of the second cavity respectively; the upper mold core correspondingly has two groove portions, and the groove portions cooperate with the boss portions.

[0012] In one embodiment, the mold includes a heating device, and the upper mold core and the lower mold core are respectively connected to the heating device.

[0013] In one embodiment, the heating device includes an upper heating plate and a lower heating plate. The upper heating plate is fixedly installed on the top surface of the upper mold core, and the lower heating plate is fixedly installed on the bottom surface of the lower mold core.

[0014] In one embodiment, the heating device is a plurality of heating rods. The upper mold core and the lower mold core are both provided with a plurality of spaced-apart heating channels, and the heating rods are respectively installed in each heating channel in a one-to-one correspondence.

[0015] According to another aspect of the present application, the present application further provides a hot bending forming device, which includes the mold according to any one of the above, a machine table main body, and a mold clamping manipulator. The machine table main body is provided with a heating area and a cooling area. The mold and the mold clamping manipulator are installed on the machine table main body, and the mold clamping manipulator is used to move the mold between the heating area and the cooling area.

[0016] The beneficial effects of the mold for hot bending forming of IML film provided by the present application are as follows: Compared with the prior art, the mold provided by the present application bends and forms the two side regions of the film, and will not cause stretching and deformation of the patterns or characters at the edge position of the film, effectively solving the problem that the patterns or characters at the edge position of the film will be stretched and deformed when using high-pressure vacuum suction forming in the prior art, improving the yield rate of products, reducing the scrap rate of the film and the production cost; Second, the mold provided by the present application is provided with a lifting channel in the lower mold core, so that the placement platform can be lifted and moved along the lifting channel under the drive of the lifting mechanism. In this way, when the placement platform descends to a predetermined position, the film can be placed on the plane jointly formed by the placement platform and the bottom wall of the second cavity for heating. In this way, when the lower mold core is heated and its temperature rises, since there is a gap between the placement platform and the lower mold core, the temperature on the surface of the placement platform will be lower than the temperature of the bottom wall of the second cavity, so that the heating rate and temperature of the middle region of the film are lower than those of the two side regions of the film. Thus, when the two regions of the film that need to be bent reach the softening temperature, they can be bent, while the middle region of the film that does not need to be bent will not reach the softening temperature, which is beneficial to protecting the middle region of the film, reducing the occurrence of process defects such as scratches, deformations, and pits, and reasonably utilizing heat, saving energy, and being beneficial to the film to cool down more quickly after forming. Third, by using the mold and the hot bending forming device, the product layout can be further effectively utilized, greatly saving the material cost of the product layout and being beneficial to mass production. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the mold provided by the embodiment of the present application;

[0019] Figure 2 It is a three-dimensional structural schematic diagram of the upper mold core of the mold provided by the embodiment of the present application in an inverted state;

[0020] Figure 3A cross-sectional view of the mold provided by the embodiment of the present application, wherein the top surface of the placement platform and the bottom wall of the cavity are in the same plane;

[0021] Figure 4 A cross-sectional view of the mold provided by the embodiment of the present application, wherein the top surface of the placement platform is higher than the bottom wall of the cavity.

[0022] Among them, each reference numeral in the figure:

[0023] 10 - upper mold; 11 - upper mold core; 1101 - first cavity; 1102 - groove part; 111 - bending part; 112 - intermediate block; 113 - heating block; 20 - lower mold; 21 - base; 22 - lower mold core; 2201 - second cavity; 2202 - lifting channel; 2203 - third cavity; 221 - convex part; 23 - placement platform; 24 - lifting mechanism; 30 - heating device; 31 - upper heating plate; 32 - lower heating plate; 300 - diaphragm. Detailed implementation manners

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0027] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0028] Please refer to together Figures 1 to 4, the mold provided by the embodiments of the present application for thermoforming IML films will now be described. The mold includes an upper mold 10 and a lower mold 20. The upper mold 10 includes an upper mold core 11. The upper mold core 11 is generally in the shape of a rectangular parallelepiped block. Two downwardly protruding and spaced-apart bending portions 111 are provided on the bottom surface of the upper mold core 11. The two bending portions 111 are respectively formed by integrally extending downward from the bottom surface of the upper mold core 11 as long convex ribs, so as to form a U-shaped first cavity 1101 between the two bending portions 111, and the first cavity 1101 opens downward.

[0029] The lower mold 20 includes a base 21, a lower mold core 22, a placement platform 23, and a lifting mechanism 24. The base 21 is used to support the lower mold core 22, the placement platform 23, and the lifting mechanism 24. In actual production, the entire lower mold 20 is fixedly installed on the machine table through the base 21. The lower mold core 22 is installed on the base 21. The lower mold core 22 has a second cavity 2201 with an upward opening. There is a lifting channel 2202 between the bottom wall of the second cavity 2201 and the bottom surface of the lower mold core 22. The placement platform 23 is used to place the film and is located in the lifting channel 2202. One end of the lifting mechanism 24 is fixedly installed on the base 21, and the other end of the lifting mechanism 24 is connected to the bottom surface of the placement platform 23 and can operably drive the lifting mechanism 24 to rise or fall along the lifting channel 2202.

[0030] Specifically, the placement platform 23 has two states. In the first state, the lifting mechanism 24 drives the placement platform 23 to descend, so that the top surface of the placement platform 23 and the bottom wall of the second cavity 2201 are in the same plane, as Figure 3 shown. At this time, the film to be formed can be placed on the plane jointly formed by the placement platform 23 and the bottom wall of the second cavity 2201 for heating.

[0031] In the second state, the lifting mechanism 24 drives the placement platform to rise, so that the top surface of the placement platform 23 is higher than the bottom wall of the second cavity 2201, as Figure 1 and Figure 4 shown. At this time, third cavities 2203 are respectively formed between the placement platform 23 and the inner walls on both sides of the second cavity 2201. It can be understood that the two third cavities 2203 are respectively located on both sides of the placement platform 23, and the third cavity 2203 is equivalent to a part of the second cavity 2201. The shape of the placement platform 23 matches the shape of the first cavity 1101, and the bending portion 111 matches the shape of the third cavity 2203. In this way, the upper mold core 11 and the lower mold core 22 can be closed, so that the placement platform 23 enters the first cavity 1101, and the two bending portions 111 respectively enter the third cavities 2203. The gap between the placement platform 23 and the inner wall of the first cavity 1101 forms a cavity for forming the film.

[0032] The working process of the mold is as follows: First, open the upper and lower molds of the mold, install the upper mold 10 and the lower mold 20 on the machine table respectively, and align the upper mold core 11 and the lower mold core 22. Drive the placement platform 23 to descend through the lifting mechanism 24 so that the top surface of the placement platform 23 and the bottom wall of the second cavity 2201 are in the same plane. Then place the diaphragm 300 to be formed on the plane jointly formed by the top surface of the placement platform 23 and the bottom wall of the second cavity 2201. At this time, most of the middle area of the diaphragm 300 is located on the placement platform 23, while the two side areas of the diaphragm 300 are respectively located on the bottom wall of the second cavity 2201. Then the machine table will heat the upper mold core 11 and the lower mold core 22, and the heat is transferred to the diaphragm 300. After the diaphragm 300 starts to soften, the lifting mechanism 24 drives the placement platform 23 to rise to a predetermined position so that the top surface of the placement platform 23 is higher than the bottom wall of the second cavity 2201. At this time, the two side areas of the diaphragm 300 are suspended on the two side edges of the placement platform 23. Then as the upper mold core 11 gradually presses down and closes with the lower mold core 22, the two bent portions 111 of the upper mold core 11 contact the two side areas of the diaphragm 300 and press down and bend the diaphragm 300. Until the upper mold core 11 and the lower mold core 22 are completely closed, the diaphragm 300 is bent and formed. At this time, the diaphragm 300 is located in the gap between the inner wall of the first cavity 1101 and the top surface of the placement platform 23, as Figure 4 shown. Finally, cool the mold through the cooling system of the machine table so that the diaphragm 300 is cooled and shaped, and then open the mold to take out the diaphragm 300.

[0033] Compared with the prior art, the mold for thermoforming the IML diaphragm provided by the present application forms the diaphragm 300 by bending the two side areas of the diaphragm 300. In this way, during the 3D forming process of the diaphragm, the pattern or text at the edge position of the diaphragm 300 will not be pulled and deformed, effectively solving the problem that the pattern or text at the edge position of the diaphragm will be stretched and deformed when high-pressure vacuum suction forming is used in the prior art, improving the yield of the product, and reducing the scrap rate of the diaphragm and the production cost;

[0034] In addition, it can be understood that if the placement platform 23 and the lower mold core 22 are an integral and non-relatively movable structure, then their temperatures after the machine table is heated and raised are the same. In order for the diaphragm 300 to be bent and formed, the height of the placement platform 23 needs to be higher than the bottom wall of the second cavity 2201. In this way, when the diaphragm 300 is placed on the placement platform 23 for heating and softening, the two side regions of the diaphragm 300 that need to be heated, softened and bent will be suspended on both side edges of the placement platform 23, and the heating rate is slow; while the middle region of the diaphragm 300 that does not need to be heated, softened and bent directly contacts the placement platform 23 and can quickly heat up. On the one hand, this leads to unreasonable heat utilization. On the other hand, after the middle region of the diaphragm 300 that does not need to be bent is heated and softened, it is also more likely to have process defects such as scratches, deformation, and pitting in the subsequent bending and demolding processes. To solve this problem, in this application, a lifting channel 2202 is provided in the lower mold core 22, so that the placement platform 23 can be lifted and moved along the lifting channel 2202 under the drive of the lifting mechanism 24. In this way, when the placement platform 23 descends to a predetermined position, the diaphragm can be placed on the plane jointly formed by the placement platform 23 and the bottom wall of the second cavity 2201 for heating. Since the machine table heats the lower mold core 22 instead of directly heating the placement platform 23, and there is also a gap between the placement platform 23 and the lower mold core 22, the temperature on the surface of the placement platform 23 will be lower than the temperature of the bottom wall of the second cavity 2201, so that the heating rate and temperature of the middle region of the diaphragm 300 are both lower than those of the two side regions of the diaphragm 300. As a result, the two side regions of the diaphragm 300 that need to be bent can be bent after reaching the softening temperature, while the middle region of the diaphragm 300 that does not need to be bent will not reach the softening temperature. This not only helps to protect the middle region of the diaphragm 300, reduce the occurrence of process defects such as scratches, deformation, and pitting, but also reasonably utilizes heat, saves energy, and is conducive to the more rapid cooling of the diaphragm 300 after molding.

[0035] In another embodiment of the present application, the lower mold core 22 is made of graphene material, and the thermal conductivity of the lower mold core 22 is greater than that of the placement platform 23.

[0036] Graphene is an excellent thermal conductive material with a very high thermal conductivity, and is very suitable for preparing thermoforming molds. The lower mold core 22 is made of graphene material, which enables the lower mold core 22 to quickly heat up after being heated by the machine table and transfer the heat to the two side regions of the diaphragm 300, so that the two side regions of the diaphragm 300 are softened. And the thermal conductivity of the lower mold core 22 is greater than that of the placement platform 23, making the placement platform 23 heat up relatively slowly and have a lower temperature, and the middle region of the diaphragm 300 is not easy to heat up and soften, thus protecting the middle region of the diaphragm 300 and reasonably utilizing heat. Optionally, the placement platform 23 can be made of ordinary steel.

[0037] In another embodiment of the present application, please refer to Figure 2 , the upper mold core 11 includes an intermediate block 112 and two heating blocks 113. The two heating blocks 113 are respectively and fixedly attached to both sides of the intermediate block 112. For example, the two heating blocks 113 can be respectively bonded to both sides of the intermediate block 112. The intermediate block 112 and the two heating blocks 113 are fixedly connected as a whole. The two bending portions 111 are respectively located at the bottoms of the two heating blocks 113. That is to say, the bending portions 111 are integrally extended downward from the bottoms of the heating blocks 113. The surfaces of the two bending portions 111 and the bottom surface of the intermediate block 112 form a U-shaped first cavity 1101. The two heating blocks 113 are made of graphene material, which enables the heating blocks 113 to quickly heat up after being heated by the machine tool, and press and thermally form the two side regions of the diaphragm 300 during the mold closing process of the upper mold core 11 and the lower mold core 22. The thermal conductivity coefficient of the heating block 113 is greater than that of the intermediate block 112, so that the intermediate block 112 located in the middle position of the upper mold core 11 heats up relatively slowly and has a lower temperature. The middle region of the diaphragm 300 is not easily heated and softened, thereby protecting the middle region of the diaphragm 300 and reasonably utilizing the heat. Optionally, the intermediate block 112 is made of ordinary steel.

[0038] In another embodiment of the present application, silica gel layers are respectively provided on the top surface of the placement platform 23 and the bottom surface of the intermediate block 112. In this way, during the mold closing and thermoforming process of the upper mold core 11 and the lower mold core 22, the silica gel layers can protect the upper and lower surfaces of the middle region of the diaphragm 300 and reduce scratches on the diaphragm 300. In addition, when foreign matters or dust adhere to the surface of the diaphragm 300, after the upper mold core 11 and the lower mold core 22 are completely closed, pits may be pressed on the surface of the diaphragm 300, and the silica gel layers can play a buffering role on the diaphragm 300 to avoid pits being pressed on the diaphragm surface by foreign matters or dust as much as possible.

[0039] In another embodiment of the present application, the placement platform 23 is provided with a plurality of spaced-apart negative pressure channels so that the diaphragm 300 can be adsorbed on the surface of the placement platform 23. Specifically, the negative pressure channels can be vertical tubular channels penetrating the top surface and the bottom surface of the placement platform 23. The plurality of negative pressure channels are spaced and evenly distributed inside the placement platform 23. When a silica gel layer is provided on the surface of the placement platform 23, each negative pressure channel also penetrates the silica gel layer. The negative pressure channels are connected to an external negative pressure device. In this way, when the diaphragm 300 is located on the top surface of the placement platform 23, a negative pressure can be formed in the negative pressure channels, thereby adsorbing the diaphragm 300 on the placement platform 23 and realizing the fixation and positioning of the diaphragm 300.

[0040] In another embodiment of the present application, as Figure 1 and Figure 2As shown, the lower die insert 22 has two boss portions 221, which are integrally formed and extend upward from the two side edges of the second cavity 2201 respectively. The upper die insert 11 correspondingly has two groove portions 1102, and the groove portions 1102 cooperate with the boss portions 221. After the upper die insert 11 and the lower die insert 22 are clamped, the two boss portions 221 respectively enter the two groove portions 1102, so that the upper die insert 11 and the lower die insert 22 are engaged with each other, thereby realizing the precise alignment of the upper die insert 11 and the lower die insert 22. In addition, during the process of the upper die insert 11 pressing down, when the boss portion 221 abuts against the groove portion 1102 and the upper die insert 11 cannot continue to press down, it means that the upper die insert 11 has been pressed down to the predetermined position, thus playing a role in motion limiting.

[0041] In another embodiment of the present application, the mold includes a heating device 30, and the upper die insert 11 and the lower die insert 22 are respectively connected to the heating device 30, so as to realize the heating and temperature rising functions of the upper die insert 11 and the lower die insert 22. For example, the heating device 30 can be a heating plate, a heating rod or a heating coil.

[0042] In another embodiment of the present application, the heating device 30 includes an upper heating plate 31 and a lower heating plate 32. The upper heating plate 31 is fixedly installed on the top surface of the upper die insert 11, and the lower heating plate 32 is fixedly installed on the bottom surface of the lower die insert 22. Through the upper heating plate 31 and the lower heating plate 32 respectively contacting and thermally conducting with the upper die insert 11 and the lower die insert 22, the heating and temperature rising of the upper die insert 11 and the lower die insert 22 are realized.

[0043] In another embodiment of the present application, the heating device 30 is a plurality of heating rods. The upper die insert 11 and the lower die insert 22 are both provided with a plurality of heating channels distributed at intervals, and the heating rods are respectively installed in each heating channel. Specifically, the upper die insert 11 and the lower die insert 22 are both provided with a plurality of horizontal tubular channels, and the tubular channels are distributed as evenly as possible inside the upper die insert 11 and the lower die insert 22. The heating rods are respectively inserted and installed in the respective tubular channels of the upper die insert 11 and the lower die insert 22. In this way, when the heating rods work, the heat can be respectively transferred to each area of the upper die insert 11 and the lower die insert 22, thereby realizing the heating and temperature rising of the upper and lower die inserts. Compared with respectively arranging heating plates on one side surface of the upper and lower die inserts, by inserting and installing heating rods in the respective tubular channels of the upper and lower die inserts, each heating rod can be evenly distributed inside the upper and lower die inserts, so as to perform zoning heating on the upper and lower die inserts, making the temperature distribution of the upper die insert 11 and the lower die insert 22 more uniform.

[0044] In other embodiments, the heating device 30 is a heating coil. Heating coils can be respectively laid on the top surface of the upper mold core 11 and the bottom surface of the lower mold core 22. After the heating coils are powered on, the upper mold core 11 and the lower mold core 22 can be heated. In addition, the heating coils can also be laid inside the upper mold core 11 and the lower mold core 22. For example, channels for accommodating the routing of the heating coils are provided inside the upper mold core 11 and the lower mold core 22, and the heating coils are threaded through the routing channels inside the upper mold core 11 and the lower mold core 22. The heating coils can be wound or coiled in a meandering manner around the upper mold core 11 and the lower mold core 22 to be as evenly distributed as possible, so that the temperature distribution of the upper mold core 11 and the lower mold core 22 is more uniform.

[0045] According to another aspect of the present application, the present application further provides a hot bending forming device. The hot bending forming device includes the above-mentioned mold, a machine table main body, and a mold clamping manipulator. The machine table main body is provided with a heating area and a cooling area, and the mold and the mold clamping manipulator are installed on the machine table main body. The mold clamping manipulator is used to move the mold between the heating area and the cooling area.

[0046] During the working process of the hot bending forming device, it is necessary to first open the upper mold 10 and the lower mold 20 of the mold. The machine table main body controls the lifting mechanism 24 to lower the placing platform 23 to a predetermined position, and then place the diaphragm 300 to be formed on the placing platform 23 of the mold. Start the heating system of the machine table main body to heat the heating device 30. The heating device 30 conducts heat to the upper mold core 11 and the lower mold core 22, thereby heating and softening the diaphragm 300. Then the machine table main body controls the lifting mechanism 24 to raise the placing platform 23 to a predetermined position, and then the machine table main body controls the upper mold core 11 to gradually press down and close the mold with the lower mold core 22, thereby performing hot bending forming on the diaphragm 300. After forming, the mold clamping manipulator moves the mold from the heating area to the cooling area, and starts the cooling system of the machine table main body to cool down the mold. The diaphragm 300 in the mold is then cooled and shaped. When the temperature of the mold drops to a predetermined value, the mold is opened to take out the diaphragm, and the mold clamping manipulator moves the mold back to the heating area for the next hot bending forming.

[0047] It is worth mentioning that in the prior art, after the diaphragm is 3D-formed by high-pressure vacuum suction molding, it is necessary to process the diaphragm through a CNC machine tool to cut off the excess scraps at the edge of the diaphragm, and finally cut the material. The CNC machining process has requirements for the spacing of the product layout on the PC+PMMA composite sheet, and the spacing between adjacent products needs to be designed to be larger, otherwise interference will occur during the machining operation. If the hot bending molding equipment provided by the present application is used to perform 3D molding on the diaphragm 300, the diaphragm 300 is first CNC-processed to cut off the scraps before the diaphragm 300 is hot-bent; in this way, during the CNC machining process of the diaphragm, the spacing of the product layout on the PC+PMMA composite sheet only needs to be able to accommodate the width of the CNC tool, so the use of the hot bending molding equipment of the present application saves more material costs for product layout.

[0048] The mold for hot bending and forming of IML diaphragms and the hot bending and forming equipment including the mold provided in the present application perform 3D forming of IML diaphragms by hot bending and forming. During the bending and forming process, the pattern or text at the edge of the diaphragm will not be pulled and deformed, which solves the process pain point of pulling and deforming the edge of the diaphragm in the prior art and greatly improves the product yield. Second, in the process of heating and softening the diaphragm 300, the heating rate and temperature of the middle area of ​​the diaphragm 300 are lower than those of the two side areas of the diaphragm, so that the areas on both sides of the diaphragm 300 that need to be bent can be bent after reaching the softening temperature, while the middle area of ​​the diaphragm 300 that does not need to be bent will not reach the softening temperature, which is beneficial to protecting the middle area of ​​the diaphragm 300, reducing the occurrence of process defects such as scratches, deformation, pitting, etc., and reasonably utilizing heat, saving energy, and facilitating faster cooling and cooling of the diaphragm 300 after forming. Third, the use of the mold and hot bending and forming equipment can further effectively utilize the product imposition, greatly saving material costs and facilitating mass production.

[0049] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A mold for thermoforming IML diaphragms, characterized in that, The mold includes: An upper mold, the upper mold includes an upper mold core, and the bottom surface of the upper mold core is provided with two downwardly protruding and spaced-apart bent portions, thereby forming a U-shaped first cavity between the two bent portions; A lower mold, the lower mold includes a base, a lower mold core, a placement platform and a lifting mechanism. The lower mold core and the lifting mechanism are both installed on the base. The lower mold core has a second cavity with an upward opening, and there is a lifting channel between the bottom wall of the second cavity and the bottom surface of the lower mold core. The placement platform is used to place the diaphragm and is located in the lifting channel; The placement platform has two states. In the first state, the lifting mechanism drives the placement platform to descend, so that the top surface of the placement platform and the bottom wall of the cavity are in the same plane. In the second state, the lifting mechanism drives the placement platform to ascend, so that the top surface of the placement platform is higher than the bottom wall of the second cavity, and third cavities are respectively formed between the placement platform and the two inner side walls of the cavity. The placement platform matches the shape of the first cavity, and the bent portion matches the shape of the third cavity; the lower mold core is made of graphene material, and the thermal conductivity of the lower mold core is greater than the thermal conductivity of the placement platform; the upper mold core includes an intermediate block and two heating blocks, and the two heating blocks are respectively fixedly attached to both sides of the intermediate block, and the two bent portions are respectively located at the bottoms of the two heating blocks; the two heating blocks are made of graphene material, and the thermal conductivity of the heating block is greater than the thermal conductivity of the intermediate block.

2. The mold according to claim 1, characterized in that, Silicone layers are respectively provided on the top surface of the placement platform and the bottom surface of the intermediate block.

3. The mold according to claim 1, characterized in that, The placement platform is provided with a plurality of spaced-apart negative pressure channels so that the diaphragm can be adsorbed on the surface of the placement platform.

4. The mold according to any one of claims 1 to 3, characterized in that, The lower mold core has two convex portions, and the two convex portions are integrally extended upward from the two side edges of the second cavity respectively; the upper mold core correspondingly has two groove portions, and the groove portions cooperate with the convex portions.

5. The mold according to any one of claims 1 to 3, characterized in that, The mold includes a heating device, and the upper mold core and the lower mold core are respectively connected to the heating device.

6. The mold according to claim 5, characterized in that, The heating device includes an upper heating plate and a lower heating plate. The upper heating plate is fixedly installed on the top surface of the upper mold core, and the lower heating plate is fixedly installed on the bottom surface of the lower mold core.

7. The mold according to claim 5, characterized in that, The heating device is a plurality of heating rods. The upper mold core and the lower mold core are both provided with a plurality of spaced-apart heating channels, and the heating rods are respectively installed in each of the heating channels in a one-to-one correspondence.

8. A hot bending forming device, characterized in that, The hot bending forming device includes the mold according to any one of claims 1-7, a machine table main body and a mold clamping manipulator. The machine table main body is provided with a heating area and a cooling area. The mold and the mold clamping manipulator are installed on the machine table main body, and the mold clamping manipulator is used to move the mold between the heating area and the cooling area.

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