Composite battery cover compression molding apparatus, method, and equipment

Abstract

The present application relates to the field of battery cover, specifically relates to a kind of composite material battery cover moulding forming device, process and equipment, device includes elastic tension clamping mechanism, lifting mechanism and mould, mould includes recessed die and male die that cooperate with each other, the temperature of mould is cooling setting temperature;Wherein, elastic tension clamping mechanism is used to clamp sheet material four around and in sheet material is pressed into shape process self-adapting tension sheet material, the temperature of sheet material before forming is hot forming temperature;Lifting mechanism is connected elastic tension clamping mechanism, for driving elastic tension clamping mechanism to descend to make sheet material distance recessed die preset distance;And after sheet material is formed, drive elastic tension clamping mechanism to rise to make sheet material demoulding;Male die is used to press down sheet material when sheet material distance recessed die preset distance to make sheet material stick close to recessed die surface to be formed as battery cover.The present application can realize the automatic production of composite material battery cover, production efficiency is high, forming quality and product consistency are good.

Description

TECHNICAL FIELD

[0001] The application relates to the field of battery covers, in particular to a composite material battery cover mold forming device, method and equipment. BACKGROUND

[0002] With the proposal of the national policy, automobile energy saving and emission reduction has become an effective way, new energy vehicles will become an important direction of national development, and the use amount of battery boxes will be larger and larger, and the battery energy density has become an important indicator of the power of new energy vehicles. Therefore, the weight of the battery box shell will directly affect the energy density of the battery box, the lighter the battery box shell, the greater the battery energy density, and the higher the new energy vehicle endurance mileage. Composite material battery cover emerges.

[0003] In the patent application with the application number 202111063488.9 and the patent name of composite material battery box upper cover rapid forming process, first, the continuous glass fiber prepreg and the glass fiber SMC sheet material are cut by a cutting machine, then the continuous glass fiber prepreg and the glass fiber SMC sheet material are laid and pasted in a laying mold for preforming blank laying, then the laid and pasted preforming blank is taken down and placed in a curing mold and cooperated with a press for pressing and curing, and finally the cured product is processed. The prior art needs manual laying and pasting for preforming, the production efficiency is low, the product consistency is poor, and the process is complex and has many procedures. SUMMARY

[0004] The technical problem to be solved by the application is to overcome the defects of the prior art and provide a composite material battery cover mold forming device which can realize automatic batch production of the composite material battery cover, has high production efficiency, good forming quality and product consistency.

[0005] In order to solve the above technical problems, the technical scheme of the application is as follows: a composite material battery cover mold forming device, comprising an elastic tension clamping mechanism, a lifting mechanism and a mold, the mold comprises a concave mold and a convex mold which cooperate with each other, and the temperature of the mold is a cooling setting temperature; wherein,

[0006] The elastic tension clamping mechanism is used for clamping the sheet material around and self-adaptingly tensioning the sheet material in the process of being pressed and formed, and the temperature of the sheet material before forming is a hot forming temperature;

[0007] The lifting mechanism is connected with the elastic tension clamping mechanism and is used for driving the elastic tension clamping mechanism to descend to a preset distance between the sheet material and the concave mold, and driving the elastic tension clamping mechanism to ascend after the sheet material is formed to demold the sheet material;

[0008] The convex mold is used for pressing the sheet material when the sheet material is at a preset distance from the concave mold, so that the sheet material is tightly attached to the surface of the concave mold to be formed into a battery cover.

[0009] Further, the elastic tension clamping mechanism comprises:

[0010] a support frame, the lifting mechanism being connected to the support frame;

[0011] four edge clamping assemblies, each edge clamping assembly being used for clamping a side edge of the sheet material;

[0012] four elastic assemblies, each elastic assembly corresponding to one edge clamping assembly and being arranged between the support frame and the corresponding edge clamping assembly, and being adapted to be pulled by the corresponding edge clamping assembly to be elastically deformed during the process of pressing the sheet material by the male die.

[0013] Further, the elastic tension clamping mechanism further comprises four mounting plates, each edge clamping assembly being mounted on one mounting plate, and the elastic assembly being connected to the edge clamping assembly through the mounting plate.

[0014] Further, the edge clamping assembly comprises:

[0015] a clamping plate set comprising a pressing plate and a support plate fixedly mounted on the mounting plate;

[0016] a pressing plate driving mechanism arranged between the mounting plate and the pressing plate, and used for driving the pressing plate to move towards the support plate to clamp the sheet material and driving the pressing plate to move away from the support plate to release the sheet material.

[0017] Further, the pressing plate driving mechanism comprises:

[0018] a connecting rod, one end of which is connected to the pressing plate;

[0019] a linkage plate, one end of which is hinged to the middle part of the connecting rod, and the other end of which is hinged to the mounting plate;

[0020] a connecting shaft, which is mounted at the other end of the connecting rod;

[0021] a lifting driving member, which is arranged between the mounting plate and the connecting shaft, and used for driving the connecting shaft to lift to make the pressing plate flip towards or away from the support plate.

[0022] The present application also provides a composite material battery cover die forming method based on the composite material battery cover die forming device, and the method comprises:

[0023] S1, the elastic tension clamping mechanism clamps the sheet material;

[0024] S2, the lifting mechanism drives the elastic tension clamping mechanism to descend, so that the sheet material descends to a preset distance from the female die;

[0025] S3, the punch is lowered, the sheet material is pressed to make the sheet material adhere to the surface of the concave die to form a battery cover, and the elastic tension clamping mechanism is self-adaptively tensioned to the sheet material during the process that the punch presses the sheet material;

[0026] S4, after the battery cover is cooled to a cooling setting temperature, the lifting mechanism drives the elastic tension clamping mechanism to rise, so that the battery cover is demolded.

[0027] Further, the method further comprises:

[0028] S5, the elastic tension clamping mechanism releases the battery cover, and the robot takes down the battery cover.

[0029] The application further provides a composite material battery cover die forming equipment, which comprises the composite material battery cover die forming device according to any one of claims 1-6.

[0030] Further, the composite material battery cover die forming equipment further comprises:

[0031] A rack has a heating position and a forming position, the lifting mechanism is slidably arranged on the rack, and the die is located at the forming position;

[0032] A moving driving mechanism is connected to the lifting mechanism and is used for driving the lifting mechanism to slide to the heating position and the forming position in sequence;

[0033] A heating mechanism is installed at the heating position and is used for heating the sheet material to a hot forming temperature when the elastic tension clamping mechanism clamps the sheet material and moves to the heating position with the lifting mechanism.

[0034] Further, the heating mechanism has a plurality of infrared heating elements, the infrared heating elements are distributed on both sides of the sheet material to simultaneously heat both sides of the sheet material; wherein,

[0035] The sheet material has an intermediate region, an edge region and a flash region arranged in sequence from inside to outside, the edge region is thicker than the intermediate region, and the elastic tension clamping mechanism is used for clamping the flash region;

[0036] The heating power of the infrared heating element used for heating the edge region is higher than that of the infrared heating element used for heating the intermediate region, and / or the density of the infrared heating element used for heating the edge region is higher than that of the infrared heating element used for heating the intermediate region, so that the intermediate region and the edge region are synchronously heated.

[0037] By adopting the technical scheme, the composite battery cover can be automatically produced in batches, the production efficiency is high, and the forming quality and product consistency are good. When the elastic tension clamping mechanism clamps the sheet material at a certain distance from the concave mold, the convex mold is pressed down to the sheet material to realize the forming of the sheet material. Because the temperature of the mold is lower than the temperature of the sheet material, heat transfer occurs when they contact, which affects the forming quality. Therefore, after the setting, the contact time between the sheet material and the mold can be reduced as much as possible before and during the forming, so as to improve the forming quality. In addition, the elastic tension clamping mechanism gives the sheet material self-adapting tensioning force during the forming of the sheet material, which can avoid the sheet material from being wrinkled during the forming and can also avoid the sheet material from being damaged, further improving the forming quality. In addition, considering that the battery cover can be demolded after being cooled to the cooling setting temperature, and the battery cover is relatively thin, the conventional internal ejection method for demolding can cause marks on the surface of the product and can also damage the product. If the product is demolded by hand, the product needs to be cooled to a temperature that can be withstood by the hand before demolding, which affects the production efficiency. The elastic tension clamping mechanism and the battery cover clamped by the elastic tension clamping mechanism can be ejected by the lifting mechanism, which can effectively prevent marks from appearing on the product and can also avoid damage, has high demolding efficiency, and further improves the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 FIG. 1 is a structural schematic view of a part outside a mold of a composite battery cover mold forming device according to the present application;

[0039] Figure 2 FIG. 2 is a partial structural schematic view of an elastic tension clamping mechanism according to the present application;

[0040] Figure 3 FIG. 3 is a structural schematic view of a composite battery cover mold forming equipment according to the present application;

[0041] In the figure, 1 is an elastic tension clamping mechanism; 11 is a support frame; 12 is an edge clamping assembly; 121 is a pressing plate; 122 is a support plate; 123 is a pressing plate driving mechanism; 1231 is a connecting rod; 1232 is a linkage plate; 1233 is a connecting shaft; 1234 is a lifting driving piece; 13 is an elastic assembly; 14 is a mounting plate; 2 is a lifting mechanism; 3 is a mold; 4 is a sheet material; 5 is a rack; 6 is a heating mechanism; and 7 is a moving driving mechanism. DETAILED DESCRIPTION

[0042] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments and in combination with the drawings.

[0043] In one embodiment, as shown in FIG. 1, Figure 1 , 2A composite battery cover mold forming device is shown in FIGS. 1, 2 and 3, which comprises an elastic tension clamping mechanism 1, a lifting mechanism 2 and a mold 3. The mold 3 comprises a female mold and a male mold which cooperate with each other. The temperature of the mold 3 is a cooling setting temperature. Wherein,

[0044] The elastic tension clamping mechanism 1 is used for clamping the four sides of a sheet material 4 and self-adaptingly tensioning the sheet material 4 during the process of the sheet material 4 being pressed to form. The temperature of the sheet material 4 before forming is a hot forming temperature.

[0045] The lifting mechanism 2 is connected to the elastic tension clamping mechanism 1 and is used for driving the elastic tension clamping mechanism 1 to descend to a preset distance between the sheet material 4 and the female mold and driving the elastic tension clamping mechanism 1 to ascend after the sheet material 4 is formed to make the sheet material 4 demold.

[0046] The male mold is used for pressing the sheet material 4 to make the sheet material 4 closely adhere to the surface of the female mold to form a battery cover when the sheet material 4 is at a preset distance from the female mold.

[0047] It should be noted that the sheet material 4 is a composite material of glass fiber and PP film, which can be formed at about 180℃ and can keep the shape at about 120℃ to complete setting. Therefore, the hot forming temperature is 180℃±15℃, the female mold and the male mold are heated by a mold temperature machine, and the temperature of both is the cooling setting temperature, which is 120℃±10℃. The sheet material 4 is formed by mold forming at the hot forming temperature and can be set at the cooling setting temperature.

[0048] Specifically, when the sheet material 4 clamped by the elastic tension clamping mechanism 1 is at a certain distance from the female mold, the sheet material 4 is pressed by the male mold to realize the forming of the sheet material 4. Because the temperature of the female mold 3 is lower than that of the sheet material 4, heat transfer will occur when they contact, which will affect the forming quality. Therefore, after the above setting, the contact time between the sheet material 4 and the mold 3 can be reduced as much as possible before and during forming, thereby improving the forming quality. In addition, during the forming of the sheet material 4, the elastic tension clamping mechanism 1 also gives the sheet material 4 a self-adapting tensioning force, which can avoid the sheet material 4 from being wrinkled during forming and can also avoid the sheet material 4 from being damaged by being pulled, thereby further improving the forming quality. In addition, considering that the battery cover can be demolded after being cooled to the cooling setting temperature and the battery cover is relatively thin, the conventional internal ejection method will cause marks on the surface of the product and may also damage the product. If the product is demolded by hand, it needs to be cooled to a temperature that can be withstood by the hand before demolding, which affects the production efficiency. The elastic tension clamping mechanism 1 and the battery cover clamped by the elastic tension clamping mechanism 1 are ejected by the lifting mechanism 2, which can effectively prevent marks from appearing on the product and can also avoid damage, has high demolding efficiency and further improves the product quality.

[0049] The lifting mechanism 2 can adopt a pneumatic cylinder, an oil cylinder or an electric cylinder, which is not limited here.

[0050] In one embodiment, as shown in Figure 1 , 2 , the elastic tension clamping mechanism 1 comprises:

[0051] a support frame 11, to which the lifting mechanism 2 is connected;

[0052] four edge clamping assemblies 12, each of which is used to clamp one side edge of the sheet material 4;

[0053] four elastic assemblies 13, each of which corresponds to one edge clamping assembly 12 and is arranged between the support frame 11 and the corresponding edge clamping assembly 12 and is adapted to be stretched by the corresponding edge clamping assembly 12 to be elastically deformed during the process of pressing the sheet material 4 by the punch.

[0054] Here, the elastic assembly 13 can be a gas spring, a common spring, etc. As shown in Figure 2 , the edge clamping assembly 12 is slidably fitted on the support frame 11 and abuts against one end of the elastic assembly 13, and the other end of the elastic assembly 13 is fixed on the support frame 11. During the process of pressing the sheet material 4 to be formed, the edge clamping assembly 12 is pulled to slide, and the edge clamping assembly 12 in turn compresses the corresponding elastic assembly 13, so that the elastic assembly 13 gives the sheet material 4 an adaptive tension, keeping the sheet material 4 in a state of being pulled in the opposite direction at all times.

[0055] It should be noted that the battery cover is already shaped at the cooling shaping temperature, and it is a relatively hard product. After the punch rises, the elastic assembly 13 rebounds to give the product an outward pulling force, but this pulling force is not large enough to cause the product to deform.

[0056] In one embodiment, in order to facilitate the connection between the elastic assembly 13 and the edge clamping assembly 12, as shown in Figure 1 , 2 , 3, the elastic tension clamping mechanism 1 further comprises four mounting plates 14, each of which is mounted on one mounting plate 14, and the elastic assembly 13 is connected to the edge clamping assembly 12 through the mounting plate 14.

[0057] In one embodiment, as shown in Figure 1 , 2 , the edge clamping assembly 12 comprises:

[0058] a clamping plate group comprising a pressing plate 121 and a support plate 122 fixedly mounted on the mounting plate 14;

[0059] a pressing plate driving mechanism 123 arranged between the mounting plate 14 and the pressing plate 121, used to drive the pressing plate 121 to move towards the support plate 122 to clamp the sheet material 4 and to drive the pressing plate 121 to move away from the support plate 122 to release the sheet material 4.

[0060] In one embodiment, as shown in Figure 1 , 2 , the pressing plate driving mechanism 123 comprises:

[0061] a connecting rod 1231, one end of which is connected to the pressing plate 121;

[0062] a linkage plate 1232, one end of which is hinged to the middle part of the connecting rod 1231, and the other end of which is hinged to the mounting plate 14;

[0063] a connecting shaft 1233, which is installed at the other end of the connecting rod 1231;

[0064] a lifting driving member 1234, which is arranged between the mounting plate 14 and the connecting shaft 1233, and is used to drive the connecting shaft 1233 to lift to turn the pressing plate 121 towards or away from the support plate 122.

[0065] In one embodiment, the telescopic driving member 1234 can be a pneumatic cylinder, an oil cylinder, etc., and is hinged to the connecting shaft 1233. When the telescopic driving member 1234 is extended, the pressing plate 121 is turned to jointly hold the sheet material 4 with the support plate 122, and when the telescopic driving member 1234 is retracted, the pressing plate 121 is turned to be released, thereby facilitating the industrial robot to place the sheet material 4 on the support plate 122 or take away the formed battery cover.

[0066] In one embodiment, as shown in Figure 1 , 2 , a composite material battery cover molding forming method based on the composite material battery cover molding forming device in the above embodiment, the method comprises:

[0067] S1, the elastic tension clamping mechanism 1 clamps the sheet material 4;

[0068] S2, the lifting mechanism 2 drives the elastic tension clamping mechanism 1 to descend, so that the sheet material 4 descends to a preset distance from the concave mold;

[0069] S3, the convex mold is lowered to press the sheet material 4 to make the sheet material 4 tightly adhere to the surface of the concave mold to be formed into a battery cover, and the elastic tension clamping mechanism 1 self-adapts to tension the sheet material 4 during the process of the convex mold pressing the sheet material 4;

[0070] S4, after the battery cover is cooled to a cooling setting temperature, the lifting mechanism 2 drives the elastic tension clamping mechanism 1 to ascend, so that the battery cover is demolded.

[0071] In one embodiment, as shown in Figure 1 , 2 , the method further comprises:

[0072] S5, the elastic tension clamping mechanism 1 releases the battery cover, and the robot takes away the battery cover.

[0073] Before step S1, S0 is further included, i.e. placing the sheet material on the elastic tension clamping mechanism 1 by the robot.

[0074] In this way, the production efficiency can be further improved, and the entire process is free of manual intervention, thereby improving the consistency of products. In addition, the battery cover is at a relatively high temperature after demolding, and the robot sucks away the battery cover by using the high-temperature-resistant suction cup, thereby facilitating subsequent cooling and cutting of the flash.

[0075] In one embodiment, as shown in Figure 1 , 2 , 3, a composite battery cover mold forming device includes the composite battery cover mold forming device according to the above embodiments.

[0076] In one embodiment, as shown in Figure 3 , the composite battery cover mold forming device further includes:

[0077] The rack 5 has a heating position and a forming position, and the lifting mechanism 2 is slidably arranged on the rack 5, and the mold 3 is located at the forming position;

[0078] The movement driving mechanism 7 is connected to the lifting mechanism 2 and is used to drive the lifting mechanism 2 to slide to the heating position and the forming position in sequence;

[0079] The heating mechanism 6 is installed at the heating position and is used to heat the sheet material 4 to a hot forming temperature when the elastic tension clamping mechanism 1 clamps the sheet material 4 and moves to the heating position with the lifting mechanism 2.

[0080] The movement driving mechanism 7 can adopt a structure of a motor, a gear, and a rack, and can also adopt a moving belt, and the structure can be various, which will not be described in detail here.

[0081] In one embodiment, as shown in Figure 1 , 2 The heating mechanism 6 has a plurality of infrared heating elements, and the infrared heating elements are distributed on both sides of the sheet material 4 to simultaneously heat both sides of the sheet material 4; wherein,

[0082] The sheet material 4 has an intermediate region, an edge region, and a flash region arranged in sequence from inside to outside, the edge region is thicker than the intermediate region, and the elastic tension clamping mechanism 1 is used to clamp the flash region;

[0083] The heating power of the infrared heating element for heating the edge region is higher than that of the infrared heating element for heating the intermediate region, and / or the density of the infrared heating element for heating the edge region is higher than that of the infrared heating element for heating the intermediate region, so that the intermediate region and the edge region are synchronously heated.

[0084] In the embodiment, the thickness of the intermediate region is 1.5 mm, and the thickness of the edge region is 3 mm. Of course, the thickness of the intermediate region and the edge region is not limited thereto, and can be other thicknesses. The embodiment adopts the manner of partition heating, and can uniformly heat each region of the sheet material 4.

[0085] The infrared heating member can be a quartz lamp tube.

[0086] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content in the specification, and must be determined according to the scope of claims.

Claims

1.A composite battery cover mold forming device, comprising an elastic tension clamping mechanism (1), a lifting mechanism (2) and a mold (3), the mold (3) comprises a female die and a male die which cooperate with each other, and the temperature of the mold (3) is a cooling setting temperature; wherein the elastic tension clamping mechanism (1) is used for clamping a sheet material (4) around and self-adaptingly tensioning the sheet material (4) during the process of the sheet material (4) being pressed to form, and the temperature of the sheet material (4) before forming is a hot forming temperature; the lifting mechanism (2) is connected to the elastic tension clamping mechanism (1), and is used for driving the elastic tension clamping mechanism (1) to descend to a preset distance between the sheet material (4) and the female die, and driving the elastic tension clamping mechanism (1) to ascend after the sheet material (4) is formed to make the sheet material (4) demold; the male die is used for pressing the sheet material (4) to make the sheet material (4) closely adhere to the surface of the female die to form a battery cover when the sheet material (4) is at the preset distance from the female die; the elastic tension clamping mechanism (1) comprises: a support frame (11), the lifting mechanism (2) is connected to the support frame (11) ; four edge clamping assemblies (12), each edge clamping assembly (12) is used for clamping a side edge of the sheet material (4) ; and four elastic assemblies (13), each elastic assembly (13) corresponds to an edge clamping assembly (12), is arranged between the support frame (11) and the corresponding edge clamping assembly (12), and is adapted to be stretched by the corresponding edge clamping assembly (12) to elastically deform during the process of the male die pressing the sheet material (4). 2.The composite battery cover mold forming device according to claim 1, wherein the elastic tension clamping mechanism (1) further comprises four mounting plates (14), each edge clamping assembly (12) is mounted on a mounting plate (14), and the elastic assembly (13) is connected to the edge clamping assembly (12) through the mounting plate (14). 3.The composite battery cover mold forming device according to claim 2, wherein the edge clamping assembly (12) comprises: a clamping plate group comprising a pressing plate (121) and a support plate (122) fixedly mounted on the mounting plate (14) ; and a pressing plate driving mechanism (123) arranged between the mounting plate (14) and the pressing plate (121), and used for driving the pressing plate (121) to move towards the support plate (122) to clamp the sheet material (4), and driving the pressing plate (121) to move away from the support plate (122) to release the sheet material (4). 4.The composite battery cover mold forming device according to claim 3, wherein the pressing plate driving mechanism (123) comprises: a connecting rod (1231), one end of which is connected to the pressing plate (121) ; a linkage plate (1232), one end of which is hinged to the middle part of the connecting rod (1231), and the other end of which is hinged to the mounting plate (14) ; and a connecting shaft (1233) mounted at the other end of the connecting rod (1231). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A lifting driving member (1234) is arranged between the mounting plate (14) and the connecting shaft (1233) and is configured to drive the connecting shaft (1233) to lift to turn the pressing plate (121) towards or away from the support plate (122). 5.A composite battery cover compression molding method, characterized in that, The composite battery cover compression molding device according to any one of claims 1-4, the method comprises: S1, the elastic tension clamping mechanism (1) clamps the sheet material (4); S2, the lifting mechanism (2) drives the elastic tension clamping mechanism (1) to descend, so that the sheet material (4) descends to a preset distance from the concave mold; S3, the convex mold descends and presses the sheet material (4) to make the sheet material (4) adhere to the surface of the concave mold to form a battery cover, and the elastic tension clamping mechanism (1) adaptively tensions the sheet material (4) during the process of the convex mold pressing the sheet material (4); S4, after the battery cover is cooled to a cooling setting temperature, the lifting mechanism (2) drives the elastic tension clamping mechanism (1) to ascend, so that the battery cover is demolded. 6.The composite battery cover compression molding method according to claim 5, characterized in that, The method further comprises: S5, the elastic tension clamping mechanism (1) releases the battery cover, and a robot takes down the battery cover. 7.A composite battery cover compression molding device, characterized in that, It comprises the composite battery cover compression molding device according to any one of claims 1-4. 8.The composite battery cover compression molding device according to claim 7, characterized in that, It further comprises: A rack (5) having a heating position and a forming position, the lifting mechanism (2) is slidably arranged on the rack (5), and the mold (3) is located at the forming position; A moving driving mechanism (7) connected to the lifting mechanism (2) is configured to drive the lifting mechanism (2) to slide to the heating position and the forming position in sequence; A heating mechanism (6) is installed at the heating position and is configured to heat the sheet material (4) to a hot forming temperature when the elastic tension clamping mechanism (1) clamps the sheet material (4) and moves to the heating position with the lifting mechanism (2). 9.The composite battery cover compression molding device according to claim 8, characterized in that, The heating mechanism (6) has a plurality of infrared heating elements, and the infrared heating elements are distributed on both sides of the sheet material (4) to heat both sides of the sheet material (4) simultaneously; wherein, The sheet material (4) has an intermediate region, an edge region and a flash region arranged from inside to outside in sequence, the edge region is thicker than the intermediate region, and the elastic tension clamping mechanism (1) is configured to clamp the flash region; The heating power of the infrared heating element for heating the edge region is higher than that of the infrared heating element for heating the intermediate region, and / or the density of the infrared heating element for heating the edge region is higher than that of the infrared heating element for heating the intermediate region, so that the intermediate region and the edge region are synchronously heated.

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