Vacuum 3D laminating jig and laminating process for electronic paper color-changing nail cover

Abstract

The electronic paper color-changing nail cover substrate single-piece 3D vacuum lamination jig and lamination process belong to the technical field of electronic paper wearable ornament processing. The jig comprises a concave die jig and a convex die. The concave die jig is provided with an independent single-piece concave cavity for placing a water-removed nail cover substrate. The convex die is matched with a flexible silica gel pressure head and a vacuum groove. The vacuum drives the silica gel pressure head to deform to realize 3D curved surface lamination. A supporting positioning plate and a positioning pin hole correct the warping of the nail piece and accurately position it. The concave and convex dies are provided with positioning pins and positioning holes to ensure the precision of die assembly. The application also provides a standardized lamination process, which comprises the whole process of cutting water-removed parts, plate flattening, pin hole positioning, vacuum exhaust, delayed demolding, defoaming and UV curing. The vacuum, pressure maintaining and ultraviolet curing parameters are controlled by a PLC grating automatic timing. The application eliminates the air bubble defects of the water-removed parts of the whole plate lamination, solves the problems of nail piece deviation and virtual lamination of curved surfaces, greatly improves the uniformity of lamination and the product yield, and is suitable for the large-scale production of electronic paper manicure.

Description

Technical Field

[0001] This invention belongs to the field of flexible electronic paper wearable jewelry processing technology, specifically involving a single-piece 3D vacuum bonding fixture for electronic paper color-changing nail substrate and a matching 3D vacuum bonding process, which is mainly applied to the OCA full bonding production process of electronic paper color-changing nail tips. Background Technology

[0002] Electronic paper color-changing nail clippers are a new type of wearable decorative device. They achieve multi-color dynamic color-changing effects by powering on electronic paper. During the production process, the nail clipper substrate, OCA (Optical Clear Adhesive), electronic paper, and carrier film need to be vacuum-bonded in a 3D curved surface.

[0003] Existing mature production processes use whole-plate nail-shaped substrates with sprue for batch OCA vacuum bonding without individual piece separation and cutting. The entire bonding fixture uses a whole-plate mold cavity structure without independent individual piece positioning structure.

[0004] The existing technology has the following core defects: The entire nail plate retains the sprue residue. During the vacuum pressing stage of mold closing, the sprue area forms a closed and narrow space. The internal air cannot be completely discharged with vacuum extraction, resulting in continuous air bubbles at the sprue position of the finished product. The air bubbles cannot be eliminated by the subsequent defoaming process, resulting in a low product yield. The mold cavity lacks an independent positioning structure, which makes it easy for the nail plate substrate to shift and warp when placed. The highest point of the nail plate's curved surface cannot be aligned with the edge of the mold cavity. After bonding, the electronic paper is misaligned with the curved surface of the nail plate, resulting in localized poor bonding and creases. The universal hard indenter cannot adapt to the 3D curved surface of the nail, resulting in uneven pressure and uneven thickness of the OCA adhesive layer at the edge of the curved surface. At the same time, the hard indenter has no buffer expansion margin and cannot adapt to the deformation of the curved surface under vacuum, which aggravates the bubble defects. The electronic paper and the nail-shaped substrate lack a precise positioning structure, resulting in large manual alignment errors and poor consistency in mass production. The bonding process lacks standardized process parameters and timing control, and the vacuum, pressure holding, and UV curing parameters lack precise controllable ranges, resulting in insufficient production stability.

[0005] Addressing the technical shortcomings of existing full-plate bonding processes, such as sprue air bubbles, alignment misalignment, incomplete surface bonding, and low product yield, this invention provides a single-piece independent mold cavity 3D vacuum bonding fixture and its supporting bonding process. By removing sprue residue, using a single-piece independent contour mold cavity, a flexible silicone pressure head, pre-positioning of the pressure plate, pin hole alignment, and a standardized vacuum UV curing sequence, the sprue air bubble problem is completely solved, improving the surface bonding accuracy and product yield. Summary of the Invention

[0006] I. The technical problem to be solved by the present invention This invention aims to overcome the shortcomings of existing whole-plate nail substrate bonding processes, such as air bubbles at the sprue, warping and misalignment of the nail pieces, poor adaptability of the rigid pressure head to the curved surface, low alignment accuracy of the electronic paper, and lack of standardized control over process parameters. It addresses the following technical problems in turn: Residual material at the sprue of the whole-plate substrate forms a closed cavity, resulting in incomplete vacuum degassing and frequent air bubbles at the sprue position in the finished product; The lack of independent single-piece mold cavities and leveling mechanisms leads to uneven and misaligned placement of the nail pieces, resulting in localized poor bonding and creases after bonding; Insufficient deformation capacity of the rigid pressure head prevents it from adapting to the curved surface of the 3D nail, resulting in uneven pressure on the adhesive layer; The lack of a pin hole alignment reference leads to large manual alignment errors between the electronic paper and the nail substrate; The lack of standardized processes and parameter ranges in the bonding process results in uncontrollable vacuum, pressure holding, and UV curing sequences, leading to poor consistency in mass production. Technical solution

[0007] (1) Basic bonding fixture To eliminate air accumulation space at the sprue and achieve adaptive curved surface venting and bonding of the vacuum-driven flexible pressure head, this invention provides a 3D vacuum bonding fixture for a single electronic paper color-changing nail cap substrate. This fixture is used to bond the nail cap substrate, electronic paper, and a carrier film into an electronic paper color-changing nail cap. The bonding fixture includes a concave mold fixture and a convex mold fixture. The concave mold fixture has several independent recesses for placing a single nail cap substrate, each recess for placing a single nail cap substrate after removing sprue residue. The convex mold fixture has several independent pressure heads for the single nail cap substrate, and the pressure heads are made of a flexible material. The structure comprises a single-finger base plate recess corresponding to a single-finger base plate pressure head after the concave mold fixture and the convex mold fixture are closed; it also includes a vacuum groove, which is disposed on the concave mold fixture and / or the convex mold fixture, and the vacuum groove is connected to the single-finger base plate recess and / or the single-finger base plate pressure head position; the vacuum groove is used to connect with an external negative pressure air source, and during the bonding process, the vacuum forces the single-finger base plate pressure head to expand and deform, bonding the nail plate base plate, electronic paper and carrier film into an integrated electronic paper color-changing nail.

[0008] The beneficial effects of this solution are as follows: Independent recesses only accommodate single substrate pieces after the sprue has been removed, eliminating the need for sealed cavities with continuous sprue marks and thus eliminating air bubbles and other defects at the source; the flexible pressure head can expand and deform under vacuum to match the 3D curved surface contour of the nail, applying pressure evenly across the entire curved surface to fully expel trapped air from the OCA adhesive layer, significantly reducing poor bonding and air bubbles; each recess corresponds to a pressure head, allowing each nail piece to be pressed independently without interference between workpieces; the vacuum groove connects all bonding areas, ensuring uniform negative pressure covering all bonding interfaces, improving vacuum degassing efficiency and shortening production cycle time.

[0009] (2) Silicone indenter hardness limiting structure Based on the above-mentioned basic bonding fixture, in order to balance the deformation capability of the flexible indenter and the structural support strength, and to avoid the problems of insufficient air release due to excessive hardness and indenter collapse and glue overflow due to excessive hardness, the independent single fingernail substrate indenter of this invention is made of silicone material; the hardness of the silicone material is greater than 20 degrees and less than 60 degrees, with a preferred hardness of 30 degrees.

[0010] The beneficial effects of this solution are as follows: silicone in the 20°~60° range combines flexible deformation capability with structural rigidity. Silicone below 20° is prone to collapse and edge overflow, while silicone above 60° has insufficient deformation, and low-lying areas on curved surfaces cannot be fully pressurized and degassed. The preferred 30° silicone pressure head has a moderate deformation range, which can completely conform to the curved surface of the nail under vacuum, while also providing support and uniform adhesive layer thickness. The silicone material is wear-resistant and UV-resistant, and is not prone to aging and cracking during long-term mass production, thus extending the service life of the fixture.

[0011] (3) Positioning pressure plate and pin hole leveling and alignment structure Based on the aforementioned basic bonding fixture, to correct nail tip warping and offset, standardize nail tip placement height, and provide an electronic paper alignment reference, this invention further includes a positioning pressure plate. A positioning pin A is provided next to the single nail substrate recess of the concave mold fixture. The convex mold fixture has an A1 positioning hole at the position corresponding to the A positioning pin. The positioning pressure plate has an A2 positioning hole corresponding to the A positioning pin. The shape of the nail substrate corresponds to the single nail substrate recess. The concave mold fixture is placed horizontally. After placing the nail substrate in the single nail substrate recess, the positioning pressure plate pushes the nail substrate completely into the single nail substrate recess, making the highest point of the nail substrate flush with the edge of the cavity in the concave mold fixture.

[0012] The beneficial effects of this solution are as follows: Positioning pin A, in conjunction with positioning pressure plate, forcibly corrects warped and offset nail plate substrates, ensuring that the nail piece completely conforms to the contour of the concave mold fixture, eliminating localized misalignment caused by uneven surface height; Positioning pin A and positioning hole A1 unify the mold closing reference of the punch and concave mold fixture, and positioning hole A2 ensures that the pressing position of the positioning pressure plate is fixed, resulting in high leveling consistency; Positioning pin A also serves as the alignment reference for the electronic paper carrier film, achieving precise coaxial alignment between the nail piece and the electronic paper, eliminating misalignment and poor edge creases.

[0013] (4) Structure of positioning pin holes for die closing Based on the above-mentioned basic fitting fixture, in order to solve the problems of misalignment between the die and the cavity and the mold closing, the present invention also includes a positioning pin and a positioning hole. The positioning pin and the positioning hole are respectively located on the die fixture or the punch fixture, and are used to fix the position of the die fixture and the punch fixture when the mold is closed.

[0014] The beneficial effects of this solution are as follows: the positioning pin and the positioning hole form a mechanical locking reference, and the mold closing automatically corrects the relative position of the concave and convex molds, ensuring that each set of silicone pressure heads accurately corresponds to the single cavity without lateral or longitudinal offset; there is no need for manual repeated calibration of the fixture, which shortens the mold closing operation time; the alignment accuracy is stable after multiple mold opening and closing operations, and the product bonding effect is stable under long-term mass production, with stable and controllable batch yield.

[0015] (5) Overall process of bonding electronic paper color-changing nail substrate The present invention also provides an electronic paper color-changing nail plate substrate bonding process, which uses any of the above bonding fixtures. In order to standardize the bonding process sequence, match the physical characteristics of 3D curved surface OCA bonding, and reduce air trapping, the process includes the following step S20: placing a single nail plate substrate into the independent cavity of the concave mold fixture. S30: Place the electronic paper with OCA adhesive and the carrier film into the die fixture; S50: Place the punch fixture above the die fixture; S60: Vacuuming the sealed cavity to remove air between the nail plate substrate and the electronic paper; S62: Allow the single nail plate substrate press head to enter the independent cavity, and the punch fixture and the die fixture close together.

[0016] The beneficial effects of adopting this solution are as follows: the process flow is standardized, with the first step being the placement of the atomizer, followed by alignment of the electronic paper, vacuum degassing, curing, and delayed demolding. The operational logic is adapted to the characteristics of curved surface bonding, effectively reducing air trapping. The process is clearly broken down, reducing defects caused by human error. Vacuum degassing followed by UV curing prevents air from being trapped inside the adhesive layer, further eliminating bubble defects from the process flow level.

[0017] (6) Pre-processing for substrate cutting and dewatering Based on the above bonding process, in order to eliminate the air-sealed cavity of the sprue from the source of materials, S10 is also included before S20: cutting the nail-shaped substrate to remove the sprue residue and separating it into a single nail-shaped substrate.

[0018] The beneficial effects of this solution are as follows: all excess material from the sprue connections is pre-cut and removed, the substrate is divided into independent single pieces, there are no continuous closed sprue areas, and the root cause of air accumulation in the sprue is completely eliminated; the size of each single substrate piece is perfectly matched with the independent cavity of the die fixture, there are no extra corners to block the vacuum channel, and the negative pressure venting is smoother; the high-temperature and long-term defoaming process after bonding is eliminated, the subsequent production process is simplified, and the overall production cycle is shortened.

[0019] (7) A-plate pre-leveling process Building upon the aforementioned bonding process, to eliminate nail warping gaps and prevent air trapping, step S21 follows S20: A single nail plate substrate is placed into an independent recess in the die fixture, and a positioning plate is placed on top to flatten all the nail plates substrates. The positioning plate can be a separate component used for flattening, ensuring that each nail plate substrate completely fits into its independent recess. Once in place, the positioning plate is removed to proceed to the next step.

[0020] The beneficial effects of this solution are: the pressure plate forcibly flattens the warped apron, making the curved surface of the apron completely fit the cavity, eliminating the height gap between the apron and the mold cavity; the apron height is uniform after pre-leveling, the gap is uniform after the electronic paper is placed, and there are no local air dead corners during the vacuum stage; the unified leveling standard ensures that each apron is placed in the same position, greatly improving the consistency of product bonding.

[0021] (8) Alignment process of bearing membrane pin holes Based on the above bonding process, in order to replace manual eye alignment and improve the alignment accuracy of electronic paper, the carrier film in step S30 includes a B limiting hole. After the electronic paper is placed on the carrier film, it is covered with OCA adhesive to form an A intermediate part. The A intermediate part is placed above the concave mold fixture, and the alignment is completed by inserting the A positioning pin into the B limiting hole.

[0022] The benefits of this solution are as follows: mechanical pin hole alignment replaces manual alignment, significantly improving alignment accuracy; the coaxiality of the electronic paper and the nail-shaped substrate is controllable, with no misalignment or overflow defects; the carrier film uniformly supports the electronic paper, the OCA adhesive layer is flat and wrinkle-free, and the electronic paper color-changing layer will not be scratched during placement; the alignment operation is simple and suitable for automated production lines.

[0023] (9) Standardized process parameter range Based on the above bonding process, in order to balance the effects of venting, bonding, and curing, and to avoid defects caused by insufficient parameters or damage to the electronic paper by excessively high parameters, in step S60: the vacuum evacuation time is 6~10s; after step S62, step S63 is also included: delayed pressure holding, the pressure of the punch fixture is 0.3~0.5MPa, and the pressure holding time is 12~20s; after the delayed pressure holding is completed, the punch fixture is lifted for demolding after 3~8s.

[0024] The beneficial effects of this solution are as follows: the 6-10s vacuum extraction range can fully remove air from the gaps between curved surfaces; if the extraction time is less than 6s, the air will not be fully expelled and bubbles will easily form; if the extraction time is more than 10s, the production cycle will be reduced; the 0.3-0.5MPa holding pressure can ensure that the silicone pressure head fully conforms to the curved surface without crushing the ultra-thin electronic paper; the 12-20s holding pressure duration ensures that the OCA adhesive can fully flow and fill the tiny gaps.

[0025] (10) Defoaming, UV curing and time-series automated control Based on the above bonding process, in order to release the internal small bubbles, solidify the OCA adhesive layer, avoid delamination during demolding, and unify the production cycle of the entire process, step S64 is added after step S63: lift the punch fixture and take out the electronic paper color-changing nail cover; S70: put the electronic paper color-changing nail cover into the defoaming furnace for high-pressure defoaming, and take it out after defoaming is completed; S80: place the electronic paper color-changing nail cover under a UV lamp and start the UV lamp to irradiate and cure the OCA adhesive; the UV lamp emits 365nm ultraviolet light, and the ultraviolet light irradiation time is 15~25s.

[0026] High-pressure defoaming eliminates extremely small air bubbles during the process, improving the quality of the electronic paper color-changing nail-shaped film. 365nm ultraviolet light (15-25s) ensures complete curing of the OCA (Optical Color Adhesive). Insufficient light results in weak adhesive layer adhesion, while excessive light exposure ages the electronic paper color-changing film. The entire process is controlled sequentially by a PLC module. After confirming the horizontal and vertical module positions via position-sensing gratings, the process automatically proceeds to the next step.

[0027] The benefits of adopting this solution include: fully automatic timing control using PLC and gratings, standardized and unified time and action of all processes, eliminating the need for manual timing and alignment, highly consistent bonding effect across different batches of products, and strong process stability.

[0028] III. Working Principle This invention employs a core principle of single-piece independent contour mold cavity + flexible silicone expansion head + vacuum negative pressure deformation bonding: Pre-cutting removes excess material from the nail plate substrate's sprue, eliminating the source of air accumulation; the concave mold fixture features independent, unconnected single-piece concave cavities, individually positioning each nail piece without connected sprue cavities; the convex mold's flexible silicone pressure head has pre-reserved deformation expansion allowance, with a curvature smaller than the actual curvature of the nail surface; after mold closing and vacuuming, negative pressure acts on the silicone pressure head through the vacuum groove, causing the pressure head to expand uniformly and adapt to the 3D nail surface. The adhesive layer air is expelled evenly by extrusion from all directions; the positioning pin, positioning plate, and bearing film limiting hole of the die fixture form a three-level alignment structure; the positioning plate pre-presses to correct the warping of the apron, ensuring that the curved surface of the apron is completely fitted with the mold cavity; the die fixture and punch are equipped with positioning pins and positioning holes to ensure that the mold closing position is completely coincident each time, and the pressure head and the cavity are precisely one-to-one; the whole process is uniformly controlled by PLC for vacuum, pressure holding, UV curing, and delayed demolding sequence, and the grating feedback of the positioning signal automatically transfers the process, realizing standardized and automated bonding production.

[0029] IV. Summary of Beneficial Effects Completely eliminates air bubble defects in sprue: Pre-cut sprue residue is combined with independent single-piece concave cavity, eliminating continuous sealed air accumulation space. Combined with a vacuum flexible pressure head for all-round air degassing, no additional defoaming process is required, and the one-time bonding yield is significantly improved. Solving problems such as nail warping and misalignment: The positioning pressure plate forces the nail to be flattened, and the pin holes are mechanically aligned to prevent misalignment of electronic paper, poor adhesion of curved surfaces, and poor creases; Uniform force application in 3D curved surface bonding: The 20~60° flexible silicone pressure head adapts to vacuum deformation, applies uniform pressure to the entire curved surface, and has a uniform OCA adhesive layer thickness with no missing or overflowing adhesive. High precision of mold closing and good production consistency: The positioning pins and positioning holes of the die lock the mold closing, and with the help of automated timing control, the bonding effect of batch products is stable. The process parameter window is complete and controllable: it defines the complete parameter range for vacuum, pressure holding, UV curing, and delayed demolding, with clear parameter boundaries, which can be directly implemented for large-scale mass production, reducing trial production and debugging costs. Attached Figure Description

[0030] Figure 1 This is a three-dimensional exploded view of the fitting fixture in Example 1; Figure 2 This is a three-dimensional exploded view of the fitting fixture part in Example 1; Figure 3 This is a three-dimensional exploded view of the fitting fixture part in Example 1; Figure 4 This is a schematic diagram of the armor plate being squeezed by a pressure plate in Example 1; Figure 5 It is middleware A in Example 1; Figure 6 This is one of the process flow diagrams for bonding electronic paper color-changing nail plate substrates; Figure 7 Schematic diagram of part of the electronic paper color-changing nail plate substrate bonding process (Part 2); Figure 8 This is a photograph of an existing technology full-plate mold fixture with sprue fitting; Figure 9 These are photos of existing technology's full-plate bonding punch fixtures; Figure 10 This is a schematic diagram of a finished nail plate produced using existing technology; Figure 11 This is a schematic diagram of a finished nail head made using this application. Detailed Implementation

[0031] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] It should be noted that the following description of preferred embodiments of this application does not constitute any limitation on this application. The description of preferred embodiments is merely an illustration of the general principles of this application. The embodiments described in this application are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or components referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and technical features numbered with Arabic numerals 1, 2, 3, etc., and designations such as "A" and "B," are used for descriptive purposes only, for the convenience of explanation, and do not represent a temporal or spatial order; they should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first," "second," and numbered with Arabic numerals 1, 2, 3, etc., may explicitly or implicitly include one or more of that feature. In the description of this application, "several" means two or more, unless otherwise expressly and specifically defined.

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific process parameters, including preferred embodiments, upper and lower limit comparison embodiments of parameters, and those skilled in the art can realize mass production based on this solution.

[0035] Figure 1 This is a three-dimensional exploded view of the fitting fixture in Example 1.

[0036] Example 1 is the optimal embodiment, with a silicone hardness of 30°; the die fixture is arranged in an array of 24 independent cavities (1020), as shown below. Figure 1 In the middle, 24 independent recesses 1020 are arranged in two rows. The recesses are strictly processed according to the drawings of the nail plate substrate supplier. The size of each recess matches the shape of the nail plate 1021 after the sprue is removed.

[0037] Figure 2 This is a three-dimensional exploded view of the fitting fixture portion in Example 1. (See attached diagram.) Figure 2 Each cavity has multiple φ2mmA locating pins fixed to its side, as shown in the figure for locating pin 2031; an annular vacuum groove is formed inside the cavity fixture, such as... Figure 2 The vacuum groove 2051 in the middle is connected to all the recesses, and a negative pressure air source interface is reserved on the side.

[0038] Figure 3Example 1: Exploded three-dimensional schematic diagram of the bonding fixture. The punch fixture is fitted with 24 flexible silicone pressure heads 3030 corresponding to 24 recesses. The silicone hardness is 30°, and the curvature of the pressure heads is less than the actual curvature of the nail substrate surface, reserving space for silicone vacuum expansion deformation. The punch has an A1 positioning hole 3031 corresponding to the A positioning pin. Positioning pins are fitted on both sides of the concave mold fixture, and positioning holes are opened at corresponding positions on the punch to achieve precise locking during mold closing.

[0039] In some embodiments not shown in the accompanying drawings, the positioning plate has 24 sets of A2 positioning holes, each corresponding to a positioning pin in the die fixture A. The bottom surface of the plate completely avoids the positioning pins, only fitting the edge area of ​​the recess. The positioning plate, not shown in the drawings, is used to align the edge of the apron with the edge of the recess. After alignment, it is removed.

[0040] In an embodiment of the electronic paper color-changing nail substrate bonding process, the steps and parameters of the bonding process are shown.

[0041] like Figure 6 Step S10: Cut the entire nail-shaped substrate, completely remove the sprue connector material, and divide it into independent single substrates. Figure 6 The middle image shows: S20: Single nail plate substrates are sequentially placed into the independent recesses of the mold fixture; S21: The locking and positioning pressure plate is pressed down, pressing the nail plate until the highest point of the nail plate is flush with the edge of the mold fixture cavity, then the pressure plate is removed; After completing the above steps, the result is as shown in the image. Figure 4 Example 1: The armor plates are squeezed by a pressure plate and arranged neatly.

[0042] Figure 5 In Example 1, intermediate component A is used. After attaching electronic paper to the carrier film, it is placed directly onto the nail plate. During the vacuum bonding process, the carrier film and electronic paper deform and press together onto the single nail plate substrate. During the deformation process, the position of the carrier film is fixed and the amount of deformation is controlled by the limiting holes opened in the carrier film.

[0043] In some embodiments, the following steps are included: S30: A φ2mm B limiting hole is opened in the carrier film. After the electronic paper is bonded with OCA adhesive, it is laid on the carrier film to obtain intermediate part A. Intermediate part A is placed above the die fixture, and positioning pin A is inserted into the B limiting hole to complete the alignment. S50: The punch positioning hole is aligned with the die positioning pin, and the die is lowered to close; the flexible silicone pressure head is embedded in the cavity. Figure 7 This demonstrates the subsequent process steps. Figure 6 The obtained pressure plate extrudes the armor plate, that is, in Figure 7 Place the die in the middle left image as shown Figure 5 The carrier film shown is then pressed onto the punch fixture.

[0044] S60: Start the negative pressure air source to draw a vacuum, the evacuation time is 8s; Pressure holding stage: mold closing pressure 0.4MPa, continuous pressure holding for 16s; the vacuum evacuation time can be 6~10s.

[0045] S62: Allow the single nail plate substrate press head to enter the independent cavity, and the punch fixture and the die fixture close together.

[0046] After mold closing, proceed to step S63: delayed pressure holding, the pressure holding pressure of the punch fixture is 0.3~0.5MPa, and the holding time is 12~20s; after the delayed pressure holding is completed, the punch fixture is lifted for demolding after 3~8s.

[0047] Step S64: Raise the punch fixture and remove the electronic paper color-changing nail plate; S70: Place the electronic paper color-changing nail clipper into the defoaming furnace for high-pressure defoaming, and remove it after defoaming is complete; S80: The electronic paper color-changing nail is placed under a UV lamp, and the UV lamp is activated to cure the OCA adhesive; the UV lamp emits 365nm ultraviolet light for 20 seconds, and the ultraviolet light duration can also be 15~25 seconds; forming a finished component; the entire process is controlled by a PLC, and the horizontal and vertical moving module grating is automatically transferred to the next process after it is in place.

[0048] like Figure 11 As shown, the finished product has no sprue or air bubbles, and the electronic paper is perfectly bonded to the 3D curved surface of the fingernail without any misalignment, poor adhesion, or creases. The OCA adhesive layer has a uniform thickness, and the first-time bonding yield is 99.6%, eliminating the need for a secondary defoaming process.

[0049] Example 2: Silicone hardness lower limit 20°, process parameters lower limit group; silicone indenter hardness 20°; vacuum evacuation for 6s, holding pressure 0.3MPa, holding time 12s; UV irradiation for 15s, demolding after a 3s delay after curing. The remaining fixture structure and process steps are completely consistent with Example 1. Implementation results: Greater silicone deformation range, complete curvature surface fit, a small number of edge micro-bubbles, yield rate 97.2%, meeting the production needs of low-standard products.

[0050] Example 3: Silicone hardness upper limit 60°, process parameters upper limit group. Silicone indenter hardness 60°; vacuum evacuation 10s, holding pressure 0.5MPa, holding time 20s; UV light irradiation 25s. The remaining fixture structure and process steps are completely consistent with Example 1. Implementation results: The silicone hardness is relatively high, the deformation range is slightly reduced, and the air can be completely expelled after the vacuum time is extended, with no bubble defects. The product yield is 99.1%, suitable for the production of thick-layer OCA adhesive products.

[0051] In comparison, existing jigs for bonding processes with sprue marks on a single sheet, such as... Figure 8 As shown, a mold for bonding without cutting the sprue and a nail-shaped base plate are connected as a whole; the finished product is as follows. Figure 10 As shown, there are obvious air bubbles, as indicated by the red circle in the image. Figure 9 It is a proportional punch fixture; Figure 9 There is no independent silicone pressure head in the middle. Figure 9 The pressure head 7010 is made of rigid plastic.

[0052] like Figure 8 The process employs a single-piece mold cavity fixture without independent single-piece recesses (6010), which is connected into an integrated nail plate substrate (6030) without cutting the sprue, without positioning pressure plates, without independent silicone pressure heads, and without standardized vacuum and UV timing parameters. After bonding, the sprue position has a high rate of bubble defects, and the nail tip warping and misalignment defects are also high, resulting in insufficient overall yield. This necessitates the addition of a long-term high-temperature defoaming process, which significantly increases production costs.

[0053] like Figure 11 This is a schematic diagram of a finished nail clipper obtained using this application. Comparison with existing technologies through three sets of embodiments demonstrates that the single-piece independent mold cavity fixture, 20~60° flexible silicone pressure head, positioning plate pre-leveling, and pin hole alignment structure of this invention, combined with a standardized vacuum-pressure holding-UV curing sequence process, can completely solve the core defects of existing whole-plate bonding processes such as sprue bubbles, alignment misalignment, and incomplete bonding of curved surfaces. The process parameters are stable and controllable within a certain range, making it suitable for the mass production of electronic paper color-changing nail clipper substrates.

[0054] This application discloses a 3D vacuum bonding fixture and bonding process for a single electronic paper color-changing nail substrate, belonging to the field of electronic paper wearable jewelry processing technology. The fixture includes a concave mold and a convex mold. The concave mold has an independent single-piece recess for placing the nail substrate with the sprue. The convex mold is matched with a flexible silicone pressure head, which, in conjunction with a vacuum groove, drives the silicone pressure head to deform and achieve 3D curved surface bonding. A positioning plate and positioning pin holes are provided to correct nail warping and ensure precise alignment. The concave and convex molds are equipped with positioning pins and positioning holes to ensure mold closing accuracy. This invention also provides a standardized bonding process, including the entire process of cutting the sprue, leveling the plate, aligning the pin holes, vacuum degassing, delayed demolding, defoaming, and UV curing. Vacuum, pressure holding, and UV curing parameters are defined and automatically time-controlled by a PLC grating. This invention eliminates the defects of air bubbles accumulating at the sprue during whole-plate bonding, solves the problems of nail offset and incomplete bonding on curved surfaces, significantly improves bonding uniformity and product yield, and is suitable for large-scale mass production of electronic paper nail art.

[0055] As shown in the accompanying drawings, the above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the content of the invention specification and drawings, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A vacuum 3D bonding fixture for electronic paper color-changing nail clippers, used to bond a nail clipper substrate, electronic paper, and a carrier film together to form an electronic paper color-changing nail clipper, characterized in that, The fitting jig includes a female mold jig and a male mold jig; The die fixture has several independent recesses for placing a single nail plate substrate. Each recess is used to place a single nail plate substrate after removing the sprue residue. The punch fixture has several independent single-finger base plate pressure heads. The pressure heads are made of flexible material. After the die fixture and the punch fixture are closed, the single-finger base plate recesses correspond one-to-one with the single-finger base plate pressure heads. It also includes a vacuum groove, which is disposed on the concave mold fixture and / or the convex mold fixture, and the vacuum groove is connected to the single nail plate substrate recess and / or the single nail plate substrate pressure head position. The vacuum groove is used to connect with an external negative pressure air source. During the bonding process, the vacuum forces the pressure head of the single nail base plate to expand and deform, bonding the nail base plate, electronic paper and carrier film into an electronic paper color-changing nail.

2. The electronic paper color-changing nail vacuum 3D bonding fixture according to claim 1, characterized in that, The independent single-finger nail substrate indenter is made of silicone material; the hardness of the silicone material is greater than 20 degrees and less than 60 degrees, with a preferred hardness of 30 degrees.

3. The electronic paper color-changing nail vacuum 3D bonding fixture according to claim 1, characterized in that, It also includes a positioning plate, wherein a positioning pin A is provided next to the single nail base plate recess of the concave mold fixture, and a positioning hole A1 is provided at the position corresponding to the positioning pin A; The positioning plate is provided with an A2 positioning hole corresponding to the A positioning pin; the shape of the nail plate substrate corresponds to the recess of the single nail plate substrate; The concave mold fixture is placed horizontally. After the nail plate is placed in the single nail plate recess, the positioning plate is used to push the nail plate completely into the single nail plate recess, so that the highest point of the nail plate is flush with the edge of the cavity of the concave mold fixture.

4. The electronic paper color-changing nail vacuum 3D bonding fixture according to claim 1, characterized in that, It also includes positioning pins and positioning holes, which are located on the concave mold fixture or the convex mold fixture, respectively, and are used to fix the position of the concave mold fixture and the convex mold fixture when the mold is closed.

5. A bonding process for an electronic paper color-changing nail substrate, using the bonding fixture described in any one of claims 1 to 4, characterized in that, Includes the following steps: S20: Place the single nail plate substrate into the independent cavity of the die fixture; S30: Place the electronic paper with OCA adhesive and the carrier film into the die fixture; S50: Place the punch fixture above the die fixture; S60: Vacuuming the sealed cavity to remove air between the nail plate substrate and the electronic paper; S62: Allow the single nail plate substrate press head to enter the independent cavity, and the punch fixture and the die fixture close together.

6. The bonding process according to claim 5, characterized in that, Before step S20, there is also step S10: cutting the nail plate substrate to remove the sprue residue and separating it into single nail plate substrates.

7. The bonding process according to claim 5, characterized in that, Step S20 is followed by step S21: placing a single nail plate substrate into the independent cavity of the concave mold fixture, and covering it with a positioning pressure plate to flatten all the nail plate substrates.

8. The bonding process according to claim 5, characterized in that, In step S30 The carrier film includes a B limiting hole. After the electronic paper is placed on the carrier film, it is covered with OCA glue to form an A intermediate part. The A intermediate part is placed above the die fixture, and the A positioning pin is inserted into the B limiting hole to complete the alignment and limiting.

9. The bonding process according to claim 5, characterized in that, In step S60: the vacuum pumping time is 6~10s; Step S62 is followed by step S63: delayed pressure holding, with the punch fixture holding pressure of 0.3~0.5MPa and holding time of 12~20s; after the delayed pressure holding is completed, the punch fixture is lifted for demolding after 3~8s.

10. The bonding process according to claim 9, characterized in that, Step S63 is followed by step S64: lifting the punch fixture and removing the electronic paper color-changing nail. S70: Place the electronic paper color-changing nail clipper into the defoaming furnace for high-pressure defoaming, and remove it after defoaming is complete; S80: Place the electronic paper color-changing nail clipper under a UV lamp and turn on the UV lamp to cure the OCA adhesive; the UV lamp emits 365nm ultraviolet light, and the UV light exposure time is 15~25s. The entire process is controlled by a PLC control module. After the horizontal and vertical modules are confirmed to be in place by the position sensing grating, the process automatically proceeds to the next step.

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