A dishing device and a dishing method for a disc-shaped polyimide film

Abstract

This invention relates to a film forming apparatus for the aerospace field, specifically to a forming apparatus and method for a disc-shaped polyimide film. It solves the technical problems of difficult and costly forming of existing disc-shaped polyimide films. The present invention provides a forming apparatus for a disc-shaped polyimide film, comprising a lower mold, an upper mold, a silicone pad, and multiple guide pins; the upper surface of the lower mold has a first profile with the same shape as the disc-shaped polyimide film; the bottom surface of the silicone pad has a second profile with the same shape as the disc-shaped polyimide film; the first profile and the second profile are coaxially fitted; the upper mold has a mold cavity at its center that matches the outer diameter of the silicone pad, and the inner wall of the mold cavity contacts the outer wall of the silicone pad; the upper mold and the lower mold are fixedly connected by multiple guide pins; the lower mold has at least one vent along its height direction, and the at least one vent is located in the recessed area of ​​the first profile.

Description

Technical Field

[0001] This invention relates to a film forming apparatus for the aerospace field, specifically to a forming apparatus and forming method for a disc-shaped polyimide film. Background Technology

[0002] Polyimide possesses excellent heat resistance and radiation resistance, making it one of the best industrially produced polymer materials in terms of these properties. Furthermore, at high temperatures, polyimide exhibits outstanding dielectric, mechanical, abrasion, and organic solvent resistance properties. Therefore, polyimide is highly favored as a specialty engineering plastic in the aerospace field. However, its application is also limited by several factors, primarily its high cost and poor processability.

[0003] A polyimide film made from polyimide material is available. The structural requirement is to process geometric indentations of different shapes on a flat 0.04mm film, resulting in a disc-like structure. This structure is used as a hydraulic sensing element to replace rubber film. A typical disc-shaped polyimide film blank is shown below. Figure 1 As shown, according to requirements, the polyimide film blank needs to be molded into... Figure 2 and Figure 3 As shown in the diagram, polyimide films are difficult to form. When the transition radius (R) is large, they can be formed in one step with a high yield. However, when the transition radius (R) is small, incomplete R and insufficient height (H) often occur during the forming process, resulting in a low part yield. Therefore, a molding device is needed, employing a suitable forming method, to improve the forming problem of polyimide films with small transition radius (R), in order to meet the usage requirements of polyimide films and improve the product yield. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of difficult molding and high molding cost of existing disc-shaped polyimide films, and to provide a molding device and molding method for disc-shaped polyimide films.

[0005] The technical solution of the present invention:

[0006] A molding device for a disc-shaped polyimide film, characterized in that it includes a lower template, an upper template, a silicone pad, and multiple guide pins;

[0007] The upper surface of the middle part of the lower template is processed with a first surface that has the same shape as the disc-shaped polyimide film.

[0008] The bottom surface of the silicone pad is processed with a second surface that has the same shape as the disc-shaped polyimide film;

[0009] The first surface and the second surface are coaxially fitted.

[0010] The upper template has a mold cavity at its center that is adapted to the outer diameter of the silicone pad, and the inner wall of the mold cavity is in contact with the outer wall of the silicone pad.

[0011] The upper and lower templates are fixedly connected by multiple guide pins, which are evenly distributed and symmetrically arranged around the circumference.

[0012] The lower template is provided with at least one vent hole along the axial direction, and the at least one vent hole is located in the concave plane area of ​​the first surface.

[0013] Furthermore, a stepped structure is provided on the edge of the upper end face of the lower template, and the stepped structure is located on the outside of the mold cavity.

[0014] Furthermore, the number of guide pins is two.

[0015] Furthermore, there is only one exhaust port.

[0016] A method for forming a dish-shaped polyimide film, using the aforementioned molding apparatus for a dish-shaped polyimide film, is characterized by comprising the following steps:

[0017] 1) Machining positioning holes with positions and dimensions that match the guide pins on the polyimide film blank;

[0018] 2) Process the silicone pad to ensure the bottom surface meets the requirements;

[0019] 3) Heat the bottom plate of the flat vulcanizing machine, and preheat the lower and upper templates to 260℃±5℃, while keeping the top plate of the flat vulcanizing machine at room temperature;

[0020] 4) Clean the upper surface of the lower template, lay the polyimide film blank flat on the upper surface of the lower template, keep the positioning hole and the guide pin hole aligned, close the upper template and lower template and fix them with the guide pin, preheat for 4-6 minutes, and then clean the surface of the polyimide film blank.

[0021] 5) Take a silicone pad, clean its bottom surface, and then put it into the mold cavity so that the bottom surface of the silicone pad contacts the upper surface of the lower template. Keep it warm and pressurized for 18-22 minutes.

[0022] 6) Remove the molding device of the disc-shaped polyimide film from the flat vulcanizing machine and open the mold to obtain the formed disc-shaped polyimide film.

[0023] Further, in step 3), the bottom plate of the flat vulcanizing machine is heated, and the lower and upper templates are preheated to 260°C;

[0024] In step 4), the preheating time after membrane closure is 5 minutes;

[0025] In step 5), the heat preservation and pressure holding time is 20 minutes.

[0026] Further, in step 5), when removing the silicone pad, observe whether the outer surface of the polyimide film is consistent with the first surface of the lower template. If they are inconsistent, take a new processed silicone pad, clean the bottom surface of the new silicone pad and put it into the mold cavity, so that the bottom surface of the new silicone pad contacts the upper surface of the lower template, and keep it warm and pressured again for 8 to 12 minutes.

[0027] Furthermore, in step 5, the re-insulation and pressure holding time is 10 minutes.

[0028] Further, in step 4), compressed air is used to clean the upper surface of the lower template;

[0029] Clean the surface of the polyimide film blank with a lint-free cloth dampened with alcohol.

[0030] The beneficial effects of this invention are:

[0031] (1) The present invention provides a molding device for disc-shaped polyimide film, which has a simple structure, is easy to operate, and has low cost. It can realize the rapid molding of disc-shaped polyimide film products and has a high product qualification rate.

[0032] (2) The present invention provides a molding device for a disc-shaped polyimide film. After the silicone plate is pressed, it deforms. Due to the clamping effect of the upper template, the bottom surface of the silicone plate deforms and coincides with the upper surface of the lower template, thus solving the problem of forming disc-shaped polyimide films.

[0033] (3) The present invention provides a molding device for a disc-shaped polyimide film, wherein a groove is provided on the upper end face of the lower template to facilitate mold closing and mold opening operations.

[0034] (4) The present invention provides a method for forming a disc-shaped polyimide film, which is simple to operate, fast to form, and has a high pass rate.

[0035] (5) The present invention provides a method for forming a disc-shaped polyimide film, which improves the forming quality of the disc-shaped polyimide film when the transition R is small by performing a single forming and a second correction, thereby increasing the product qualification rate. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a polyimide film preform;

[0037] Figure 2 This is a schematic diagram of the disc-shaped polyimide film structure after molding;

[0038] Figure 3 for Figure 2 Enlarged view of point A;

[0039] Figure 4This is a schematic diagram of the structure of the silicone pad in the disc-shaped polyimide film molding device of the present invention before the bottom surface is processed;

[0040] Figure 5 This is a schematic diagram of the structure of a disc-shaped polyimide film molding device according to the present invention.

[0041] Figure label:

[0042] 1-Lower template, 2-Upper template, 3-Silicone pad, 4-Guide pin, 5-Vent hole, 6-Positioning hole. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] like Figure 5 As shown, the present invention provides a molding device for a disc-shaped polyimide film, comprising a lower template 1, an upper template 2, a silicone pad 3, and two guide pins 4.

[0045] The upper surface of the middle part of the lower template 1 is machined with a first surface that is identical in shape to the disc-shaped polyimide film, and the bottom surface of the silicone pad 3 is machined with a second surface that is identical in shape to the disc-shaped polyimide film. The structure of the silicone pad 3 before processing is as follows: Figure 4 As shown, after mold closing, the first and second mold surfaces are coaxially fitted to press the polyimide film blank into the required dish shape. To facilitate mold opening and closing, a stepped structure is provided on the upper edge of the lower mold plate 1, and the stepped structure is located outside the mold cavity.

[0046] The upper template 2 is used to position the silicone pad 3. A mold cavity adapted to the outer diameter of the silicone pad 3 is located at the center of the upper template 2, and the inner wall of the mold cavity contacts the outer wall of the silicone pad 3. The upper template 2 and the lower template 1 are fixedly connected by two guide pins 4. Multiple guide pins 4 are evenly distributed circumferentially and symmetrically arranged. The guide pins 4 prevent radial movement of the upper template 2, ensuring accurate mold closing and pressing position. A vent 5 is provided on the lower template 1 along the axial direction. One vent 5 is located in the concave plane area of ​​the first mold surface. In other embodiments, multiple vents 5 can be provided according to actual conditions to prevent air stagnation.

[0047] Meanwhile, the present invention also provides a method for forming a dish-shaped polyimide film, using the above-mentioned forming apparatus for a dish-shaped polyimide film, comprising the following steps:

[0048] 1) such as Figure 1 As shown, positioning holes 6 with positions and dimensions that match those of guide pins 4 are machined on the polyimide film blank.

[0049] 2) Use a punch to cut out the silicone pad 3 so that the bottom surface meets the requirements;

[0050] 3) Heat the bottom plate of the flat vulcanizing machine and preheat the lower template 1 and the upper template 2 to 260°C. In other embodiments, the temperature can be 260°C ± 5°C. The upper plate of the flat vulcanizing machine is kept at room temperature.

[0051] 4) Use compressed air to clean the dust, impurities, etc. on the upper surface of the lower template 1. Lay the polyimide film blank flat on the upper surface of the lower template 1, keeping the positioning hole and the hole of the guide pin 4 aligned. Close the upper template 2 and the lower template 1 and fix them with the guide pin 4. Preheat for 5 minutes. In other embodiments, preheat for 4 to 6 minutes. Use a lint-free cloth soaked in alcohol to clean the dust, impurities, etc. on the surface of the polyimide film blank.

[0052] 5) Take a silicone pad 3, clean its bottom surface carefully with a lint-free cloth dipped in alcohol, and then put the silicone pad 3 into the mold cavity, so that the bottom surface of the silicone pad 3 contacts the upper surface of the lower template 1, and the second surface of the bottom surface of the silicone pad 3 coincides with the first surface of the upper surface of the lower template 1. Keep it warm and pressurized for 20 minutes. In other embodiments, the warm and pressurized time can also be 18 to 22 minutes.

[0053] Remove the silicone pad 3. When removing it, observe whether the shape of the polyimide film is consistent with the first surface of the lower template 1. If they are not consistent, take a new processed silicone pad 3, clean the bottom surface of the new silicone pad 3 and put it into the mold cavity, so that the bottom surface of the new silicone pad 3 contacts the upper surface of the lower template 1, and the second surface of the bottom surface of the silicone pad 3 coincides with the first surface of the upper surface of the lower template 1. Keep it warm and pressurized again for 10 minutes. In other embodiments, the warm and pressurized time can also be 8 to 12 minutes.

[0054] 6) Remove the molding device of the disc-shaped polyimide film from the flat vulcanizing machine and open the mold to obtain the formed disc-shaped polyimide film.

[0055] The disc-shaped polyimide film obtained by the molding method of the present invention has good molding quality and high pass rate.

[0056] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make some improvements and changes without departing from the principle, but these should also be considered within the scope of protection of the present invention.

Claims

1. A method for forming a disc-shaped polyimide film, applicable to a molding device for a disc-shaped polyimide film, the molding device for the disc-shaped polyimide film comprising a lower template (1), an upper template (2), multiple silicone pads (3), and multiple guide pins (4); the upper surface of the middle part of the lower template (1) is processed with a first profile that is the same as the shape of the disc-shaped polyimide film; the bottom surface of the silicone pads (3) is processed with a second profile that is the same as the shape of the disc-shaped polyimide film; the first profile and the second profile are coaxially fitted; the upper template (2) is provided with a mold cavity at its center that is adapted to the outer diameter of the silicone pads (3), the inner wall of the mold cavity is in contact with the outer wall of the silicone pads (3); the upper template (2) and the lower template (1) are fixedly connected by multiple guide pins (4), the multiple guide pins (4) are evenly distributed around the circumference and symmetrically arranged; at least one vent hole (5) is provided on the lower template (1) along the axial direction, the at least one vent hole (5) is located at the position of the concave plane area of ​​the first profile; Its features are, Includes the following steps: 1) Machining positioning holes (6) on the polyimide film blank, the position and size of which are adapted to the guide pin (4). 2) Process the silicone pad (3) to make the bottom surface conform to the requirements; 3) Heat the bottom plate of the flat vulcanizing machine, and preheat the lower template (1) and upper template (2) to 260℃±5℃, while keeping the upper plate of the flat vulcanizing machine at room temperature; 4) Clean the upper surface of the lower template (1), lay the polyimide film blank flat on the upper surface of the lower template (1), keep the positioning hole consistent with the hole of the guide pin (4), close the upper template (2) and the lower template (1) and fix them through the guide pin (4), and after preheating for 4~6 minutes, clean the surface of the polyimide film blank. 5) Take a silicone pad (3), clean its bottom surface, and then put it into the mold cavity so that the bottom surface of the silicone pad (3) contacts the upper surface of the lower template (1) and keep it warm and pressurized for 18~22 minutes. When removing the silicone pad (3), observe whether the outer surface of the polyimide film is consistent with the first surface of the lower template (1). If they are inconsistent, take a new processed silicone pad (3), clean the bottom surface of the new silicone pad (3) and put it into the mold cavity, so that the bottom surface of the new silicone pad (3) contacts the upper surface of the lower template (1), and keep it warm and pressurized again for 8~12 minutes. 6) Remove the molding device of the disc-shaped polyimide film from the flat vulcanizing machine and open the mold to obtain the formed disc-shaped polyimide film.

2. The method for forming a dish-shaped polyimide film according to claim 1, characterized in that: The lower template (1) has a stepped structure on the upper edge, and the stepped structure is located outside the mold cavity.

3. The method for forming a dish-shaped polyimide film according to claim 2, characterized in that: The number of guide pins (4) is two.

4. The method for forming a dish-shaped polyimide film according to claim 3, characterized in that: There is one exhaust port (5).

5. The method for forming a dish-shaped polyimide film according to claim 1, characterized in that: In step 3), the bottom plate of the flat vulcanizing machine is heated, and the lower template (1) and the upper template (2) are preheated to 260°C; In step 4), the preheating time after mold closing is 5 minutes; In step 5), the heat preservation and pressure holding time is 20 minutes.

6. The method for forming a dish-shaped polyimide film according to claim 5, characterized in that: In step 5), the time for the second heat preservation and pressure preservation is 10 minutes.

7. The method for forming a dish-shaped polyimide film according to claim 6, characterized in that: In step 4), use compressed air to clean the upper surface of the lower template (1); Clean the surface of the polyimide film blank with a lint-free cloth dampened with alcohol.

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