Preform molding mold, preform molding apparatus, and preform molding method

Abstract

To provide a mold for molding a preform capable of suppressing the generation of wrinkles on the product surface of a film at the time of molding the preform.SOLUTION: The mold for preform molding is a mold for preform molding for preform molding a film, and includes a first mold and a second mold, and the second mold has a split structure including a second first split mold and a second second split mold.SELECTED DRAWING: Figure 6-7

Description

[Technical Field]

[0001] The present disclosure relates to a preform molding die for preforming a film used in a method for producing a resin part by inserting a preform molded and shaped film into an insert molding die to integrate the molded resin and the film, and also to a preform molding apparatus and a preform molding method using the die. [Background technology]

[0002] In conventional technology, as shown in Fig. 1, in order to prevent wrinkles in the film, which is an appearance issue, when preforming films 4 and 5, the margin 5 on the outer periphery of the film other than the product shape is held down by parts of molds 1 and 2. In this way, while the film is fixed, the films 4 and 5 are stretched by preforming molds 1, 2, and 3 to be shaped into the product shape (see, for example, Patent Document 1).

[0003] The films 4 and 5 formed into the product shape were subjected to secondary processing, in which unnecessary portions of the margin 5 on the outer periphery were trimmed as necessary. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-180736 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional method of Patent Document 1 has the problem that a margin 5 is provided around the periphery of the film 4 as shown in Figure 1, and films 4, 5 larger than the product size are used, resulting in a lot of material waste and an increase in material costs. In addition, the margin 5 of the film around the periphery of the product must be trimmed in a post-process, which increases the cost of secondary processing.

[0006] Furthermore, depending on the product shape, when the upper and lower dies are pressed simultaneously, wrinkles cannot escape and are crushed, resulting in wrinkles on the product surface and a poor appearance.

[0007] The present disclosure aims to solve the above-mentioned problems and provide a preform molding die that can suppress the occurrence of wrinkles on the product surface of a film during preform molding. [Means for solving the problem]

[0008] The preform molding die according to the present disclosure is a preform molding die for preforming a film, and comprises a first mold and a second mold, and the second mold has a split structure including a 2-1 split mold and a 2-2 split mold.

[0009] The preform molding method according to the present disclosure is a preform molding method for preforming a film, and includes the steps of placing a film in a preform molding die equipped with a first die and a second die having a split structure including a 2-1 split die and a 2-2 split die, and pressing the 2-1 split die and the 2-2 split die sequentially to press the film. [Effects of the Invention]

[0010] According to the preform molding die of the present disclosure, at least one of the first die or the second die has two or more split dies, so that by sequentially pressing the split dies, wrinkles can be smoothed out and the occurrence of wrinkles on the product surface can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a cross-sectional structure of press working in the prior art. [Figure 2A] 1 is a plan view showing a product shape of a preformed film according to a first embodiment of the present disclosure. FIG. [Figure 2B]2B is a schematic cross-sectional view showing a cross-sectional structure seen in the direction AA of FIG. 2A. [Figure 2C] 2B is a schematic cross-sectional view showing a cross-sectional structure seen in the direction BB in FIG. 2A. [Figure 3] FIG. 1 is a schematic cross-sectional view showing the cross-sectional structure of a film used in the study of the present disclosure. [Figure 4] 1 is a schematic diagram showing a state before press working in which a film is set in a core die of a preform molding die according to a first embodiment of the present disclosure. FIG. [Figure 5-1] 10 is a schematic perspective view showing a state in which a 2-1 split mold, out of the split cavity molds, is pressed against a film in the preform molding mold according to the first embodiment. FIG. [Figure 5-2] FIG. 5-2 is a schematic cross-sectional side view showing the cross-sectional structure of the 2-1 split mold, the film, and the first mold in FIG. 5-1. [Figure 6-1] 10 is a schematic perspective view showing a state in which a 2-1 split mold is pressed against a film in one step of the preform molding method according to the first embodiment. FIG. [Figure 6-2] 10 is a schematic perspective view showing a state in which a 2-2 split mold is pressed against a film in one step of the preform molding method according to the first embodiment. FIG. [Figure 6-3] 10 is a schematic perspective view showing a state in which the second and third split molds are pressed against the film in one step of the preform molding method according to the first embodiment. FIG. [Figure 6-4] 10 is a schematic perspective view showing a state in which the second to fourth split molds are pressed against a film in one step of the preform molding method according to the first embodiment. FIG. [Figure 6-5] 10 is a schematic perspective view showing a state in which a 2-5th split mold and a 2-6th split mold are pressed against a film in one step of the preform molding method according to the first embodiment. FIG. [Figure 6-6] 10 is a schematic perspective view showing a state in which a 2-7 split mold is pressed against a film in one step of the preform molding method according to the first embodiment. FIG. [Figure 6-7]10 is a schematic perspective view showing a state in which a 2-8 split mold is pressed against a film in one step of the preform molding method according to the first embodiment. FIG. [Figure 7] 1 is a block diagram showing the configuration of a preform molding device according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The preform molding die according to the first aspect is a preform molding die for preforming a film, and comprises a first die and a second die, and the second die has a split structure including a 2-1 split die and a 2-2 split die.

[0013] The preform molding die according to the second aspect is the first aspect, and at least one of the first die and the second die may be provided with a positioning pin for a positioning tab provided on one side of the film.

[0014] In the preform molding die according to the third aspect, in the first or second aspect, the clearance between the first die and the 2-1 split die, or the clearance between the first die and the 2-2 split die, may be set narrower than the thickness of the film.

[0015] The preform molding die according to a fourth aspect is any one of the first to third aspects, and may be provided with a mechanism for rolling up a part of the film to the back side at at least one location.

[0016] The preform molding die according to a fifth aspect is any one of the first to fourth aspects, and may have a release coating on at least one of the first die and the second die.

[0017] The preform molding die according to the sixth aspect may be any of the first to fifth aspects, wherein at least one of the first die, the 2-1 split die, and the 2-2 split die has a heating or cooling function.

[0018] A preform molding apparatus according to a seventh aspect includes the preform molding die according to any one of the first to fifth aspects, and a control unit that controls the first die and the second die.

[0019] The preform molding method according to the eighth aspect is a preform molding method for preforming a film, and includes the steps of placing a film in a preform molding die equipped with a first die and a second die having a split structure including a 2-1 split die and a 2-2 split die, and pressing the 2-1 split die and the 2-2 split die sequentially to press the film.

[0020] A ninth aspect of the preform molding method is the same as the eighth aspect, and in the step of placing the film in the first mold, the first mold may have a positioning pin for a positioning tab on one side of the film, and the film may be placed in the first mold by passing the positioning pin through the positioning tab.

[0021] The preform molding method according to the tenth aspect may be the same as in the eighth or ninth aspect, and may further include, after the press processing step, a step of pressing and holding the film between the first mold and the second mold until the temperatures of the first mold and the second mold become 60°C or less.

[0022] The preform molding method according to the eleventh aspect is any one of the eighth to tenth aspects, wherein the clearance between the first mold and the 2-1 split mold, or the clearance between the first mold and the 2-2 split mold, may be set narrower than the thickness of the film.

[0023] The preform molding method according to the twelfth aspect is any one of the eighth to eleventh aspects, wherein in the step of press-forming the film, the temperature of at least one of the first mold, the 2-1 split mold, and the 2-2 split mold may be set to a temperature higher than or equal to the glass transition temperature Tg of the substrate of the film.

[0024] A preform molding method according to a thirteenth aspect is any one of the eighth to twelfth aspects, wherein in the step of press-forming the film, a part of the film may be rolled up on the back side at least at one or more locations.

[0025] In the preform molding method according to the fourteenth aspect, in the above ninth aspect, in the step of press-forming the film, the second-first split mold and the second-second split mold may be pressed sequentially starting from the side closer to the positioning pin of the first mold.

[0026] The preform molding method according to the fifteenth aspect may be any of the eighth to thirteenth aspects, in which, in the step of pressing the film, the 2-1 split mold and the 2-2 split mold may be pressed in order starting with the mold having the largest contact area with the film.

[0027] The preform molding method according to the 16th aspect may be such that, in any one of the above-mentioned 8th to 13th aspects, in the step of press-processing the film, the 2-1 split mold and the 2-2 split mold are pressed sequentially along one direction.

[0028] The preform molding method according to the seventeenth aspect may be any of the eighth to thirteenth aspects, in which, in the step of press-processing the film, the 2-1 split mold and the 2-2 split mold may be pressed sequentially from the inside to the outside.

[0029] Hereinafter, a preform molding die, a preform molding device, and a preform molding method according to embodiments will be described with reference to the accompanying drawings. In the following description, the same components are given the same reference numerals, and duplicate explanations may be omitted. To facilitate understanding, the drawings mainly show each component in a schematic manner. Furthermore, the thickness, length, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of creating the drawings. Note that the present invention is not limited to the following embodiments.

[0030] (Embodiment 1) <Preformed film (shaped product, product shape)> Fig. 2A is a plan view showing a product shape of a preformed film according to embodiment 1 of the present disclosure, Fig. 2B is a schematic cross-sectional view showing a cross-sectional structure as viewed in the AA direction of Fig. 2A, and Fig. 2C is a schematic cross-sectional view showing a cross-sectional structure as viewed in the BB direction of Fig. 2A. As shown in Figure 2B, for example, the preformed film (formed product) that is the target of preform molding does not have a flat surface as a characteristic of the product shape, and each part has a curved surface with different curvatures (R2.57, R894.73, R9.99, R1.2) that do not have a constant curvature. For this reason, conventional methods require a margin of film, which results in a large amount of material waste. Furthermore, if there is no margin of film, the film will be stretched at the pressed parts, which can lead to whitening or breakage of the stretched parts. Furthermore, if the decoration range requires decoration all the way to the edge of the product, it is not possible to decorate the film all the way to the backside, which creates design restrictions.

[0031] <Film> FIG. 3 is a schematic cross-sectional view showing the cross-sectional structure of the film used in the study of the present disclosure. As shown in FIG. 3, the film 10 used in this disclosure is pre-decorated, with the decorative layer 10 being formed by painting or printing. The film is pre-trimmed to a shape similar to the product shape before being preformed. For example, a Thomson die can be used to cut the film into the product shape. A Thomson die is a punching die whose shape varies for each product. If design and manufacturing requirements require, for example, positioning accuracy (within ±0.2 mm), positioning tabs 26 for installation on the preform die are placed in appropriate positions. As shown in FIG. 4, there are no restrictions on the number, shape, or location of these positioning tabs 26.

[0032] <Preform molding mold> FIG. 4 is a schematic diagram showing a state before press processing in which a film 13 is set in a core mold (lower mold, first mold) 12 of a preform molding mold according to embodiment 1 of the present disclosure. FIG. 5-1 is a schematic cross-sectional view showing a state in which a 2-1 split mold 17, one of the divided cavity molds, is pressed against a film 16 in a preform molding mold according to embodiment 1. FIG. 5-2 is a schematic side cross-sectional view showing the cross-sectional structure of the 2-1 split mold 17, the film 16, and the first mold 15 of FIG. 5-1. The first mold 15 may also be referred to as a core mold or a lower mold. The second mold may also be referred to as a cavity mold or an upper mold. The preform molding die according to the first embodiment is a preform molding die for preforming a film 16, and includes a core die (first die) 15 and a cavity die (second die) 17. The cavity die 17 has a divided structure including two or more split dies 17. For example, in Figs. 6-1 to 6-7 described below, the cavity die has a divided structure including eight split dies. The number of split dies is not limited as long as it is two or more.

[0033] The cavity mold (second mold, upper mold) of this preform molding mold has a split structure on the product surface side, and the preform molding mold bends and draws the film from the inside to the outside.

[0034] The order in which the split dies are pressed depends on whether positional accuracy is required for the film. If positional accuracy is required, the split dies are pressed starting with the area most requiring positional accuracy. For example, the split dies closest to the positioning pins of the core die 15 may be pressed sequentially. If positional accuracy is not required, the split dies with the largest contact area with the film may be pressed sequentially. Pressing the split dies with the largest contact area with the film first stabilizes the film. Alternatively, multiple split dies may be pressed sequentially in one direction. By pressing the split dies sequentially in one direction, the excess film can be pressed in one direction from one end to the other, thereby preventing wrinkles. Multiple split dies may be pressed sequentially from the inside to the outside. By pressing sequentially from the inside to the outside, the excess film can be pressed from the inside to the outer edge, preventing wrinkles. For example, pressing both ends of the film first eliminates any escape route for wrinkles that may occur due to excess film deformation during bending and drawing. For this reason, the split dies adjacent to the split dies pressed first may be pressed in sequence to spread them apart. Alternatively, the split dies that are in contact with each other via a split dies that have already been pressed may be pressed in sequence. By pressing adjacent split dies in sequence, the directionality of the film being pressed can be maintained. In this case, by pressing the periphery of the split dies that have already been pressed in sequence, the directionality from the split dies that have already been pressed can be maintained.

[0035] The gap between the core mold (lower mold, first mold) and cavity mold (upper mold, second mold) of the preform molding die is set, for example, to a uniform clearance of 60% of the film thickness. The reason for setting the clearance to 60% is that if the clearance is larger than the film thickness, the film is more likely to wrinkle, which may result in poor appearance. To prevent poor appearance, a clearance smaller than the film thickness is set to prevent excess material generated during the film deformation process from wrinkling. Therefore, the clearance between the core mold (lower mold, first mold) and cavity mold (upper mold, second mold) of the preform molding die of the present invention may be set in the range of 20% to 100%. If the clearance is less than 20%, the clearance becomes too narrow, increasing the pressure applied to the film, which can cause the adhesive layer to fuse to the die, or the film is easily scratched on the exterior because it is rubbed during preforming. Furthermore, the pressure applied to the film varies depending on the location on the film, which can cause the material to shift during preforming in part of the film, making it more likely to wrinkle. A more preferable range is 50% to 80%.

[0036] This preform molding die may be equipped with a mechanism for folding a portion of the film to the back side at at least one location. The excess portion of the film deformed to the product shape during preform molding is collected on the back side of the molded part, for example, so that it does not appear on the product's exterior, allowing preform molding processing to be performed without wrinkles on the film surface on the product's exterior surface.

[0037] 4, at least one of the first mold and the second mold may be provided with a positioning pin 27 for a positioning tab 26 provided on one side of the film 13. This allows for accurate positioning. At least one of the first mold and the second mold may have a release coating.

[0038] The preform molding die may have a heating or cooling function in at least one of the first die, the 2-1 split die, and the 2-2 split die. Alternatively, the temperature may be raised in advance to a temperature above the glass transition point (Tg) of the film (°C) and below Tg + 20 (°C), and the film trimmed to the product shape is placed in the lower die for preform molding. In order to deform the film to the product shape during preform molding, the temperature of the preform molding die must be maintained above the Tg (°C) of the film. Temperatures below Tg (°C) reduce the flexibility of the film and reduce the transfer rate of the preform processing. Temperatures above Tg + 20 (°C) can cause the film substrate to deteriorate due to heat, leading to discoloration and a decrease in physical properties. However, the temperature range is not limited to this range as long as the same effect as in the first embodiment can be obtained by selecting an optimal temperature range depending on the type of substrate.

[0039] According to the preform molding die of embodiment 1, at least one of the first die or the second die has two or more split dies, so that by sequentially pressing the split dies, wrinkles can be smoothed out and the occurrence of wrinkles on the product surface can be suppressed.

[0040] <Preform molding equipment> Fig. 7 is a block diagram showing the configuration of a preform molding apparatus 40 according to embodiment 1. The apparatus comprises the preform molding die 32 and a control unit 34 that controls the first die 16 and the second die 30. As shown in Fig. 7, the second die 30 has eight split dies, 2-1 split die 17 to 2-8 split die 24. Note that this is just one example, and the number of split dies may be two or more.

[0041] <Preform molding method> 6-1 to 6-7 are schematic perspective views showing the steps of the preform molding method according to the first embodiment. In this preform molding method, the above-described preform molding die can be used. In this preform molding method, the film has a symbol mark arranged thereon, and the shape of the symbol mark requires positional accuracy. The preform molding method according to the first embodiment is a method for preforming a film, and includes the following two steps. (i) In a preform molding die comprising a first die 15 and a second die having a split structure including a 2-1 split die 17 and a 2-2 split die 18, a film 16 is placed on the first die 15 (film placement process). In this case, the film is set on the first die (lower die, core die) regardless of whether it has a tab or not. The temperature of the first die is previously raised to or above the glass transition temperature Tg of the film. (ii) The 2-1 split mold 17 and the 2-2 split mold 18 are pressed together in sequence to press the film 16 (pressing step).

[0042] The preform molding method according to the first embodiment will be specifically described below with reference to FIGS. 6-1 to 6-7. (1) First, as shown in Figure 6-1, press processing is performed in the direction of the arrow using the 2-1 split mold 17, which is a split mold of the cavity mold (upper mold, second mold) of the preform molding mold separated from the product surface with the symbol mark. (2) Next, as shown in FIG. 6-2, the second-second split mold 18 adjacent to the second-first split mold 17 is used to press a portion of the inclined surface. (3) As shown in Figure 6-3, press forming is performed by pressing the remaining slopes with the 2-2 split mold 18 and the adjacent 2-3 split mold 19. As shown in Figures 6-1 to 6-3, adjacent split molds are pressed sequentially, and the margins of the film 16 are pushed out from the inside to the outside to perform preform molding.

[0043] (4) Next, as shown in FIG. 6-4, the lower end and side surfaces are pressed together using the second-third separate mold 19 and the adjacent second-fourth separate mold 20. (5) Next, as shown in Fig. 6-5, bending of the corner portions is carried out using a 2-5 split die 22 adjacent to the 2-2 split die 18 and the 2-4 split die 20, and a 2-6 split die 22 adjacent to the 2-1 split die 17. In this case, the 2-5 split die 22 and the 2-6 split die 22 may be pressed simultaneously. (6) As shown in FIG. 6-6, the side surfaces are bent using the 2-1 split mold 17, the 2-6 split mold 22, and the adjacent 2-7 split mold 23. (7) As shown in Figures 6-7, the 2-7th split mold 23 and the adjacent 2-8th split mold 24 roll up the portion of the film 16 that has been pushed outward from the inside to the back of the product portion. In this disclosure, the excess portion that is generated by pushing the film 16 outward from the inside can be prevented from appearing on the product exterior, thereby suppressing the occurrence of wrinkles. In addition, the decorative area can be expanded and the margins can be minimized, reducing material waste. 6-1 to 6-7, there are no restrictions on the size of the pressing area or the pressing direction, and it is also possible to press multiple split dies simultaneously. Note that the above-mentioned division method and press processing order in embodiment 1 are just examples, and there is no problem with changing the pressing order of the split dies or the range of division as appropriate.

[0044] (8) After preforming in the state shown in Figure 6-7, the preform processing mold temperature may be removed at a temperature 20°C or more lower than the Tg (°C) of the film substrate. When the temperature drops below the desired value, the cavity mold and core mold of the preform processing mold are opened, and the preformed film is removed. In other words, the mold temperature is lowered below the Tg with the mold closed, and then the film is removed. This prevents heat-induced deformation of the preformed film, resulting in the production of highly accurate preformed products. Furthermore, since the film printing may melt and adhere to the mold when removed during preform processing, a release coating may be applied to the cavity mold, core mold, or both. Note that the release coating is not necessarily required, as it is significantly affected by the mold temperature.

[0045] According to the preform molding method of the first embodiment, the film is shaped at a temperature equal to or higher than the glass transition point Tg, and the film is removed in a temperature range sufficiently lower than Tg, thereby preventing a decrease in the transfer rate of the shaped film. In addition, by setting the clearance between the first mold (lower mold, core mold) and the second mold (upper mold, cavity mold) to 20% to 100% of the film thickness, it is possible to prevent wrinkles caused by excess material due to deformation of the film. Furthermore, by making the second mold (upper mold) a split structure and pressing the split second mold (upper mold) in order, the film surface can be pressed down, spreading out any wrinkles that may occur in the excess film to the periphery while forming the shape, enabling preform molding processing with no wrinkles on the film product surface.

[0046] As described above, the preform molding method according to the first embodiment, unlike conventional preform molding methods, enables wrinkle-free film preform molding without restricting the film margins with the outer periphery of the mold. This reduces material loss and makes it possible to suppress material costs. Furthermore, since there is no need to process the film margins through secondary processing, it is also possible to suppress processing costs. By reducing material costs, it is possible to suppress the direct material costs of the film, for example, by approximately 20% to 50%. [Industrial Applicability]

[0047] The preform molding die according to the present disclosure can be suitably used to manufacture molded articles obtained by insert molding, in which a sheet such as a film is fixed to an insert molding die and injection molded, such as panels for automotive parts. [Explanation of symbols]

[0048] 1 Upper mold 2 Lower mold 3. Mold for creating the shape 4 Film (Products Department) 5 Film (margin) 6. Film part with target shape 7. Target shape forming part 8. Hard coat layer of film 9 Film substrate 10 Film decorative layer 11 Film adhesive layer 12 Core mold (lower mold, first mold) 13 Film 14 Film tab placement range 15 Core mold (lower mold, first mold) 16 Product shape range of core mold (lower mold) 17. 2nd-1st split mold (cavity mold, upper mold) 18 No. 2-2 split mold 19 2nd-3rd split mold 20 2nd-4th split mold 21 2nd-5th split mold 22 2nd-6th split mold 23 2nd-7th split mold 24 2nd-8th split mold 26 Positioning tab 27 Locating pin 30 cavity mold (upper mold, second mold) 32 Preform molding mold 34 Control Unit 40 Preform molding equipment (press processing equipment)

Claims

1. A preform molding die for preforming a film, A preform molding die comprising a first die and a second die, the second die having a split structure including a 2-1 split die and a 2-2 split die.

2. The preform molding die according to claim 1 , wherein at least one of the first die and the second die is provided with a positioning pin for a positioning tab provided on one side of the film.

3. The clearance between the first mold and the 2-1 split mold, or the clearance between the first mold and the 2-2 split mold is set narrower than the thickness of the film. The preform molding die according to claim 1.

4. The preform molding die according to claim 1 , further comprising a mechanism for rolling up a portion of the film to the back side at at least one location.

5. The preform mold according to claim 1 , wherein at least one of the first mold and the second mold has a release coating.

6. The preform molding die according to claim 1, wherein at least one of the first die, the second-1st split die, and the second-2nd split die has a heating or cooling function.

7. The preform molding die according to claim 1; a control unit that controls the first mold and the second mold; A preform molding device comprising:

8. A preform molding method for preforming a film, comprising: In a preform molding die comprising a first die and a second die having a split structure including a 2-1 split die and a 2-2 split die, a step of placing a film on the first die; a step of sequentially pressing the second-1 split mold and the second-2 split mold to press the film; A preform molding method comprising:

9. 9. The preform molding method according to claim 8, wherein in the step of placing the film in the first mold, the first mold has a positioning pin for a positioning tab on one side of the film, and the film is placed in the first mold by passing the positioning pin through the positioning tab.

10. 9. The preform molding method according to claim 8, further comprising, after the press working step, a step of pressing and holding the film between the first mold and the second mold until the temperatures of the first mold and the second mold become 60°C or less.

11. The clearance between the first mold and the 2-1 split mold, or the clearance between the first mold and the 2-2 split mold is set narrower than the thickness of the film. The preform molding method according to claim 8.

12. In the step of press-forming the film, the temperature of at least one of the first mold, the second-first split mold, and the second-second split mold is set to a temperature equal to or higher than the glass transition temperature Tg of the base material of the film. The preform molding method according to claim 8.

13. The preform molding method according to claim 8 , wherein in the step of pressing the film, a portion of the film is rolled up on the back side at least at one or more locations.

14. 10. The preform molding method according to claim 9, wherein in the step of press-forming the film, the 2-1 split mold and the 2-2 split mold are pressed sequentially from the side closer to the positioning pin of the first mold.

15. The preform molding method according to claim 8, wherein in the step of press-forming the film, the second-1 split mold and the second-2 split mold are pressed sequentially from the mold having a larger contact area with the film.

16. The preform molding method according to claim 8, wherein in the step of press-forming the film, the second-1 split mold and the second-2 split mold are pressed sequentially along one direction.

17. The preform molding method according to claim 8, wherein in the step of press-forming the film, the 2-1 split mold and the 2-2 split mold are pressed sequentially from the inside to the outside.

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