Multi-section glue injection molding method

Abstract

A multi-section glue injection molding method is applied to an electronic product, a cover plate of the electronic product comprises a concave surface and a flange connected to the top edge of the concave surface, the method is used for conducting glue injection on the flange and the concave surface, and the method comprises the steps that before glue injection, a glue injection runner corresponding to a glue injection structure finally needing to be formed is divided with the concave surface facing upwards, and the glue injection runner is communicated with the concave surface; the glue injection runner is divided into a plurality of cavities from bottom to top; manufacturing a plurality of glue injection molds corresponding to the plurality of cavities according to the division result of the glue injection runner; during glue injection, a plurality of manufactured glue injection molds corresponding to the plurality of cavities are used for independently injecting glue into the plurality of cavities one by one according to the sequence from bottom to top; according to the invention, a complex glue injection runner is simplified into a plurality of sections of simple runners, so that the original problem of lack of glue during glue injection is effectively improved, the appearance effects of no collapse and no lack of glue of a product can be achieved, and meanwhile, the problems of poor strength and insufficient air tightness caused by lack of glue can be improved and met.

Description

Technical Field

[0001] The invention relates to the field of glue injection molding of electronic products, and in particular to a multi-stage glue injection molding method. Background Art

[0002] In the assembly field of mobile phones, watches and more electronic products, glue injection is usually used to seal and reinforce the cover module, which can meet the strength and waterproof performance requirements after the whole machine is assembled, and at the same time make the black border of the display module narrower.

[0003] Existing glue injection technology usually uses thermosetting or UV curing glue for glue injection, and performs overmolding on the outer edges of components such as cover plates, display modules, antennas, etc. Among them, in terms of the glue used, thermosetting glue usually has an opaque appearance, higher injection viscosity and higher strength after curing, while UV glue usually has a transparent appearance and better fluidity; in terms of process, thermosetting glue is usually injected into a ready-made mold under normal pressure or low pressure, vacuum environment, and injected once, and then heated and cured at a lower temperature, and demolded to obtain the injected product. UV glue requires a prefabricated light-transmitting mold, which is injected under normal pressure or low pressure vacuum environment, and then UV cured and demolded to obtain the product. Usually, due to the mold design, secondary curing is required in the insufficient light area. As for the existing UV glue, since it needs good light for curing, it cannot be used for more complex structures or opaque molds. As for thermosetting glue, since the product contains electronic components and has certain temperature requirements, the glue used can only be cured at a lower temperature. It has great limitations and often has problems of high viscosity and insufficient fluidity, which also poses difficulties for complex structures.

[0004] For existing products that need to be injected with glue, the cover plate usually adopts a 2D or 2.5D shape, and the display module is pasted on it for injection. The product structure is simple and the flow channel is smooth. For the consideration of processing efficiency and product yield, the product is usually placed horizontally to obtain a good appearance and waterproof effect and strength effect. However, for a large number of 3D structure cover plates in the existing market, since they usually have a deep display module fitting concave surface, in the existing technology, UV type glue cannot be cured due to excessive depth, and thermosetting glue has poor fluidity, which will cause a large amount of glue shortage on the surface of the product after injection. Moreover, because the display module assembly structure of some products is not stacked in order from large to small area, the product structure forms a semi-isolated cavity, and the glue flow channel will have two or more semi-independent cavities. The flow rate of glue in different cavities and the connecting gaps between cavities is different, which will cause the glue to slowly transfer from the cavity with a faster flow rate to the cavity or gap with a slower flow rate, resulting in the collapse of the product surface and more serious glue shortage. In the prior art, there is no relevant practice for glue injection of cover plate-module with complex structure, and the probability of glue deficiency in the product obtained by using the prior art is very high.

[0005] The above information disclosed in this Background section is included only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is currently known to a person of ordinary skill in the art. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a multi-stage injection molding method in view of the above-mentioned defects of the prior art.

[0007] The technical solution adopted by the present invention to solve the technical problem is: construct a multi-stage glue injection molding method, which is applied to electronic products. The cover of the electronic product includes a concave surface and a flange connected to the top edge of the concave surface. The method is used to inject glue on the flange and the concave surface. The method includes:

[0008] Before the glue is injected, the glue injection flow channel corresponding to the glue injection structure to be finally formed is divided with the concave surface facing upward, and the glue injection flow channel is divided into a plurality of cavities from bottom to top;

[0009] According to the injection flow channel division result, a plurality of injection molds corresponding to the plurality of cavities are manufactured;

[0010] When injecting glue, the glue is injected into the multiple cavities one by one in a bottom-up order using a plurality of glue injection molds corresponding to the multiple cavities.

[0011] Furthermore, in the multi-stage injection molding method described in the present invention, the injection mold corresponding to each cavity includes: a molding release surface corresponding to the dividing line of a cavity adjacent upward or conforming to the required shape of the product, a sealing structure pressed with the injection structure of a cavity adjacent downward and / or pressed with the product, and at least two glue inlet and outlet ports.

[0012] Furthermore, in the multi-stage injection molding method described in the present invention, the process of dividing the injection channel specifically includes: dividing the injection channel into two upper and lower cavities according to whether it is the appearance part of the injection structure that needs to be finally formed, and the upper cavity forms the appearance part of the injection structure that needs to be finally formed after injection.

[0013] Furthermore, in the multi-stage injection molding method described in the present invention, the process of dividing the injection channel specifically includes: intercepting a representative cross-section of the injection channel perpendicular to the glue flow direction, using the representative cross-section as the target graphic, and executing a cavity processing strategy to divide the cavity.

[0014] Furthermore, in the multi-stage injection molding method of the present invention, the method of intercepting the representative cross section is:

[0015] Cutting a plurality of cross sections of the glue injection channel perpendicular to the glue flow direction, and selecting cross sections with large differences according to the area change of each cross section relative to the cross sections before and after it;

[0016] For each screened cross section, the cross section is used as a target graphic to execute the cavity processing strategy to divide the cavity, and the cross section with the largest number of cavities is selected as the representative cross section.

[0017] Furthermore, in the multi-stage injection molding method described in the present invention, the cavity processing strategy includes: determining the maximum inscribed circle within the current target figure, determining a cavity dividing line based on the currently determined maximum inscribed circle, and if the injection channel still has remaining areas other than the already determined cavity, then taking the remaining areas as the new target figure and executing the cavity processing strategy again.

[0018] Furthermore, in the multi-stage injection molding method of the present invention, the step of determining a dividing line of a cavity based on the currently determined maximum inscribed circle specifically includes:

[0019] The diameter of the currently determined maximum inscribed circle is used as the characteristic size of the cavity to be determined next;

[0020] Determine all available inflection points of the injection flow channel;

[0021] For each available inflection point: take it as the first endpoint of the line segment, move the second endpoint of the line segment on the contour of the injection flow channel, if the length of the line segment when the second endpoint is on both sides of a certain position is longer than the length of the line segment at the certain position, take the certain position as the position of the second endpoint of the line segment, and take the line segment at this time as a target line;

[0022] By comparing each of the target lines with the characteristic size, the target line that meets the requirements is selected as the dividing line of the cavity.

[0023] Furthermore, in the multi-stage injection molding method of the present invention, the step of comparing each of the target lines with the characteristic dimensions and selecting the target line that meets the requirements as the dividing line of the cavity specifically includes:

[0024] The target lines whose lengths are greater than a preset ratio of the characteristic size are screened out, and only the target lines whose lengths are less than or equal to the preset ratio of the characteristic size are retained.

[0025] Furthermore, in the multi-stage injection molding method described in the present invention, the method also includes: after the injection of each cavity is completed, solidification is performed first, and then the injection of glue is performed in the cavity immediately above; or, after the injection of glue in each cavity is completed, solidification is not performed, and the injection of glue in the cavity immediately above is continued.

[0026] Furthermore, in the multi-stage glue injection molding method described in the present invention, the mold is a mold suitable for thermosetting glue, or a UV-transparent mold suitable for UV-curing glue.

[0027] The multi-stage glue injection molding method of the present invention has the following beneficial effects: the present invention divides the complex glue injection structure of the product into multiple cavities from bottom to top, distinguishes the multiple cavities, and uses multiple glue injection molds corresponding to the multiple cavities to inject glue into the multiple cavities one by one in a bottom-up order, that is, multi-stage glue filling is realized, and the complex glue injection flow channel is simplified into multiple sections of simple flow channels, so that the original glue injection lack problem is effectively improved, and the product can achieve the appearance effect of no collapse and no glue lack, and at the same time it can improve and meet the strength problem and insufficient airtightness problem caused by lack of glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative work:

[0029] Figure 1 It is a flow chart of the multi-stage injection molding method of the present invention;

[0030] Figure 2 It is a schematic diagram of the glue injection structure that needs to be finally formed on the cover plate;

[0031] Figure 3 It is a schematic diagram of the appearance segmentation cavity division method;

[0032] Figure 4 It is a schematic diagram of the maximum inscribed circle segmentation cavity division method;

[0033] Figure 5 This is one of the schematic diagrams of the division method of the inflection point characteristic cavity;

[0034] Figure 6 This is the second schematic diagram of the inflection point characteristic cavity division method;

[0035] Figure 7 is a schematic diagram of the glue injection process of the first embodiment;

[0036] Figure 8 is a schematic diagram of the glue injection process of the second embodiment;

[0037] Fig. 9 is a schematic diagram of the glue injection process of Example 3;

[0038] Among them, the reference numerals in the figure are:

[0039] 1. Cover plate of electronic product; 2. Assembly of electronic product; 3. Glue injection structure; 101. Flange; 102. Concave surface; 311-312. Two-stage glue injection structure of embodiment 1; 321-324. Four-stage glue injection structure of embodiment 2; 331-333. Three-stage glue injection structure of embodiment 3. DETAILED DESCRIPTION

[0040] In view of the defects in the prior art that a large number of glue shortages are generated on the surface of products after glue filling, forming semi-isolated cavities, which leads to collapse of the product surface and more serious glue shortage, the present invention proposes a multi-stage glue injection molding method, which divides the complex glue injection structure of the product into multiple cavities from bottom to top, distinguishes the multiple cavities, and uses multiple glue injection molds corresponding to the multiple cavities to inject glue into the multiple cavities one by one in order from bottom to top, that is, multi-stage glue filling is realized, and the complex glue injection flow channel is simplified into multiple sections of simple flow channels, so that the original glue injection and glue shortage problem is effectively improved, and the appearance effect of no collapse and no glue shortage of the product can be achieved. At the same time, the strength problem and the problem of insufficient airtightness caused by glue shortage can be improved and satisfied.

[0041] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Typical embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0042] refer to Figure 1 The multi-stage injection molding method of the present invention comprises:

[0043] S100: before glue injection, dividing a glue injection flow channel corresponding to the glue injection structure to be finally formed with the concave surface facing upward, and dividing the glue injection flow channel into a plurality of cavities from bottom to top;

[0044] The method of the present invention can be applied to electronic products. Usually, such complex structures will form multiple cavities. Figure 2 , Figure 2 The cross section perpendicular to the glue flow direction is shown. The thin oblique line part is the final glue injection structure 3 to be formed, the thick oblique line is the assembly part 2 of the electronic product, and the dotted area is the cover plate 1 of the electronic product (usually made of glass). The cover plate 1 includes a concave surface 102 and a flange 101 connected to the top edge of the concave surface. Figure 2The cover plate 1 is placed horizontally with the concave surface 102 facing upwards. The depth direction when the concave surface 102 faces upwards is defined as the up-down direction. The method of the present invention is used to inject glue on the flange 101 and the concave surface 102. The injection structure 3 to be formed is as follows: Figure 2 The so-called glue injection flow channel refers to the space occupied by the glue injection structure 3 that needs to be formed in the end. This space is called the glue injection flow channel before glue injection, and the glue injection structure 3 is formed after glue injection.

[0045] Because the glue will produce speed loss due to the viscosity of the side walls of the glue injection channel when it flows, the present invention divides the cavity perpendicular to the flow direction. After the division, the speed loss inside each cavity is roughly similar, and the speed loss between different cavities is quite different. Some flow very fast, and some flow very slowly. In this way, when different cavities are filled with glue separately, each cavity is very stable and it is not easy to have cavities.

[0046] It should be noted that the injection channel is divided into multiple cavities from bottom to top. The multiple cavities are not strictly stacked up and down, but refer to the overall trend of all cavities from bottom to top. The latter cavity is usually higher than the former cavity. There may be a situation where the same height distribution exists, but there will not be a situation where the latter cavity is lower than the former cavity. The former cavity and the latter cavity here are distinguished according to the order of injection. The cavity injected first is called the former cavity, and the cavity injected later is called the latter cavity.

[0047] It should be noted that the “plurality” mentioned in this article refers to two or more than two.

[0048] Three cavity division methods are introduced below.

[0049] Method 1: Appearance segmentation cavity division method.

[0050] The process of dividing the injection channel of method 1 specifically includes: dividing the injection channel into two upper and lower cavities according to whether it is the protruding appearance part of the injection structure that needs to be formed in the end, and the upper cavity forms the protruding appearance part of the injection structure that needs to be formed in the end after injection of glue.

[0051] like Figure 2 The cross section perpendicular to the glue flow direction is shown, in which the portion protruding from the flange 101 belongs to the protruding appearance portion ①, so in this embodiment, this portion is divided into the upper cavity 1, and the remaining portion ② is divided into the lower cavity 2, as shown in FIG. Figure 3In addition, when dividing the upper and lower cavities, the dividing line is corrected by using the nearby inflection points as much as possible, so that the dividing line connects the inflection points. For example, the appearance part ① and the remaining part ② do not directly use the horizontal extension line of the flange 101 as the dividing line, but start from the inflection point of the flange 101 and the concave surface 102, and slightly downward to the nearby concave inflection point to form a dividing line.

[0052] This way of dividing the cavity can ensure that the appearance and function of the uppermost cavity 1 are relatively good during the subsequent glue injection, while the number of sections is small and the production efficiency is high.

[0053] Method 2: Maximum inscribed circle segmentation cavity division method.

[0054] The specific process of dividing the glue injection flow channel in method 2 is to intercept a representative cross section of the glue injection flow channel perpendicular to the glue flow direction, such as Figure 4 The figure shows a representative cross section. Taking the representative cross section as the target figure, the following cavity processing strategy is executed:

[0055] S1: Determine the maximum inscribed circle in the current target figure;

[0056] S2: determining a dividing line of a cavity based on the currently determined maximum inscribed circle;

[0057] S3: If there are remaining areas in the injection flow channel except for the determined cavity, the remaining areas are used as new target graphics and the cavity processing strategy is executed again, that is, jumping back to S1.

[0058] That is, by repeatedly performing steps S1-S3, cavities are divided one by one from the injection flow channel, such as referring to Figure 4 , first divide out cavity 1, divide out cavity 2 for the remaining area, then divide out cavity 3 for the remaining area, and so on.

[0059] The detailed process of step S1 is introduced below.

[0060] The center of the maximum inscribed circle is the point with the largest distance from the inside of the figure to the boundary, and its radius is the distance. To find the maximum inscribed circle of a two-dimensional closed figure, existing methods can be used to determine it, and there is no restriction on this. For example, it can be determined based on the medial axis. First, the medial axis of the figure is calculated (the Voronoi diagram algorithm or skeleton extraction algorithm can be used) to find the medial axis of the figure, and then the point with the largest distance to the boundary on the medial axis is found, which is the center of the circle, and the distance is the radius. For another example, a numerical optimization method can be used. For complex figures, an iterative optimization algorithm can be used to approximate the solution: first discrete sampling is performed to generate candidate points inside the figure (for example, the inside of the figure is uniformly gridded, and each grid intersection is a candidate point); then the distance is calculated: for each candidate point, the closest distance to the boundary of the figure is calculated (such as ray casting or space division acceleration); finally, the maximum distance is screened out: the candidate point with the largest distance is selected as the center of the circle, and the distance is the radius.

[0061] The detailed process of step S2 is introduced below.

[0062] S21) Using the diameter of the currently determined maximum inscribed circle as the characteristic dimension of the cavity to be determined next, and determining all available inflection points of the injection flow channel.

[0063] The so-called available inflection point refers to the inflection point of the contour belonging to the remaining area, and the line connecting the inflection point and the center of the inscribed circle will not intersect with the contour of the injection channel, nor will it intersect with the already divided dividing line. For example, when cavity 1 is divided for the first time, except for C4 and C7, all other inflection points C1-C9 are available inflection points; when cavity 2 is divided for the second time, only C1 and C2 are available inflection points; when cavity 3 is divided for the third time, only C4, C5, and C6 are available inflection points; when cavity 4 is divided for the fourth time, only C5, C6, C7, and C8 are available inflection points.

[0064] S22) For each available inflection point: take it as the first endpoint of the line segment, move the second endpoint of the line segment on the contour of the injection flow channel, if the length of the line segment when the second endpoint is on both sides of a certain position is longer than the length of the line segment at the certain position, then take the certain position as the position of the second endpoint of the line segment, and take the line segment at this time as a target line.

[0065] S23) By comparing each of the target lines with the characteristic size, the target lines that meet the requirements are selected as the dividing lines of the cavity. Specifically, the target lines whose length is greater than a preset ratio (such as 9 / 10) of the characteristic size are screened out, and the target lines retained after screening are line segments whose length is less than or equal to 9 / 10 of the characteristic size. After screening, there may be more than one target line for a single inflection point.

[0066] It should be noted that, after a maximum inscribed circle is determined, if no dividing line can be found, the area enclosed by all available inflection points corresponding to the current maximum inscribed circle represents the cavity to be found.

[0067] Figure 4 The double-headed arrows in the figure represent dividing lines. It can be understood that after finding the dividing line, the cavity can be determined. The space formed by the dividing line and the contour of the injection flow channel after it goes around the direction of the injection flow channel is the corresponding cavity.

[0068] It can be seen that the present invention uses a dividing line to divide the figure, and the area of ​​the current maximum inscribed circle corresponds to the cavity obtained by this subdivision. The next maximum inscribed circle is drawn in the remaining area, and so on, and finally the entire cross-sectional figure is divided into two or more cavities.

[0069] Among them, the representative cross section can be selected based on experience. For example, if some cross sections are obviously more complex than other cross sections, they can be determined as representative cross sections. The present invention provides a representative cross section interception method based on the number of cavities, specifically: first, along the flow direction of the glue (the concave surface 102 is facing upward, the glue is flowing horizontally, or flowing horizontally), uniformly intercept multiple cross sections of the glue injection channel that are perpendicular to the flow direction of the glue. In order to reduce the amount of data processing, before selecting a representative cross section, you can also filter out cross sections with large differences based on the area change of each cross section relative to the cross sections before and after it. For example, if the area of ​​a certain cross section changes by more than 10% compared to the area of ​​the cross sections before and after it, it can be considered that the difference of the certain cross section is large and it is filtered out; then, for each filtered cross section, use it as a target graphic to execute the cavity processing strategy to divide the cavity, and select the cross section with the largest number of cavities as the representative cross section.

[0070] Compared with method 1, method 2 has a better molding appearance effect, but because the number of segments may increase, it is more suitable for situations with higher requirements.

[0071] Method 3: Inflection point characteristic cavity division method.

[0072] Method 3 mainly uses the inflection point as the reference to draw a horizontal line (except for the inflection point where the flange connects with the concave surface, which also allows a vertical line). Figure 2 The cross section is divided into multiple regular shapes from bottom to top, refer to Figure 5-6 There are two splitting results. This method can generally be split based on experience. Figure 6 It can also be understood as dividing the Figure 3 The lower cavity 2 in the embodiment is divided into two cavities based on method 3. Figure 5 , 6The figures ①, ②, ③, and ④ separated by the middle dividing line correspond to cavities 1, 2, 3, and 4 respectively.

[0073] S200: manufacturing a plurality of injection molds corresponding to a plurality of cavities according to the injection flow channel division result;

[0074] Each cavity corresponds to a glue injection mold. The present invention does not limit the type of glue, nor does it limit the type of mold. The mold may be a mold suitable for thermosetting glue, or a UV light-transmitting mold suitable for UV curing glue. In fact, the mold includes but is not limited to thermosetting and UV. The shape of the glue injection mold must ensure that the cavity to be injected with glue next can be injected with glue. Therefore, the glue injection mold corresponding to each cavity includes: a molding release surface corresponding to the dividing line of a cavity immediately above (that is, the next cavity) or conforming to the required shape of the product, a sealing structure that is pressed with the glue injection structure of a cavity immediately below (that is, the previous cavity) or / and pressed with the product, and at least two glue inlets and outlets. The positions of the glue inlet and outlet of the glue injection mold can be satisfied as long as the cavity can be filled with glue. By injecting glue into the glue inlet of the glue injection mold, the glue will enter the corresponding cavity from the glue outlet of the glue injection mold.

[0075] It should be noted that the corresponding to the dividing line of the cavity includes coinciding with the dividing line, or adjusting based on the dividing line. For example, there may be several dividing lines whose overall trend is more obvious, and these dividing lines can be replaced by an equivalent dividing line. In short, in mold making, for the sake of simplicity, sealing effect or size control, it is not necessarily exactly consistent with the dividing line. The dividing line can be slightly adjusted as long as the effect difference is acceptable.

[0076] It is understandable that after the mold is manufactured, in actual operation, it is only necessary to use the mold that has been manufactured to manufacture or adjust the mold dimensions related to the size.

[0077] S300: When injecting glue, use a plurality of glue injection molds corresponding to the plurality of cavities to inject glue into the plurality of cavities one by one in a bottom-up order.

[0078] According to the glue injection sequence, when the first cavity is injected with glue, the first glue injection mold is used. The first glue injection mold is matched with the product to enclose the first cavity. The first glue injection mold will be sealed with the product through a sealing structure. By injecting glue into the glue inlet of the first glue injection mold, the glue will enter the first cavity from the glue outlet of the first glue injection mold; after the first cavity is injected with glue, the second glue injection mold is replaced. The second glue injection mold, the product and the glue injection structure of the first cavity are enclosed to form the second cavity. The second glue injection mold will be sealed with the product and the glue injection structure of the first cavity through a sealing structure. By injecting glue into the glue inlet of the second glue injection mold, the glue will enter the second cavity from the glue outlet of the second glue injection mold; and so on.

[0079] It should be noted that after the glue injection in each cavity is completed, it can be cured first, and then the glue injection in the cavity immediately above (i.e., the next cavity) can be carried out; or, after the glue injection in each cavity is completed, it is not cured, and the glue injection in the cavity immediately above (i.e., the next cavity) can continue.

[0080] For thermosetting glue, it is necessary to use the temperature required by the glue to cure. Generally, it is divided into multiple sections for glue injection and curing. Since the glue is the same, its strength is generally the same. In general, each section will be cured separately. For UV curing glue, UV curing is required. In particular, for UV curing glue, after each section of glue injection is completed, it must be cured before the next section of glue injection can be carried out. Figure 5-6 For example, because the depth of curing required is too deep and there is obstruction, UV curing can only achieve better curing effect by curing in sections 2, 3, and 4 respectively when there is no obstruction above section 1.

[0081] Three embodiments are given below.

[0082] Embodiment 1

[0083] refer to Figure 7 , this embodiment is to inject glue to obtain Figure 2 The glue injection structure 3. This embodiment first adopts method 1 to divide the obtained Figure 3 The cavity 1 and cavity 2 shown in the figure are arranged according to Figure 3 Two molds 1 and 2 are made of a cavity.

[0084] When injecting glue, first use the first mold 1 pair Figure 3 The cavity 2 is injected with thermosetting glue, such as Figure 7 As shown in (a), after the glue is injected, it is cured in a 60 degree oven for 40 minutes to form a glue injection structure 311 of the cavity 2; Figure 7 As shown in (b), the mold 2 is used again. Figure 3The cavity 1 is injected with thermosetting glue, and then cured in a 60 degree oven for 40 minutes to form an injection structure 312 of the cavity 1. The injection structures 311 and 312 together constitute the final injection structure 3. In the figure, A1 represents a sealing structure.

[0085] Embodiment 2

[0086] refer to Figure 8 , this embodiment is to inject glue to obtain Figure 2 The glue injection structure 3. This embodiment first adopts method 2 to divide the obtained Figure 4 The cavity 1, cavity 2, cavity 3 and cavity 4 shown are arranged according to Figure 4 Four molds 1, 2, 3, and 4 are made with a cavity.

[0087] When injecting glue, first use the mold 3 pairs Figure 4 The cavity 3 is injected with thermosetting glue, such as Figure 8 As shown in (a), after the glue is injected, it is cured in a 60 degree oven for 40 minutes to form a glue injection structure 323 of the cavity 3; Figure 8 As shown in (b), the mold 4 is used again Figure 4 The cavity 4 is injected with thermosetting glue, and after injection, a 60-degree oven is used to cure for 40 minutes to form an injection structure 324 of the cavity 4; Figure 8 As shown in (c), the mold 1 is used again. Figure 4 The cavity 1 is injected with thermosetting glue, and then cured in a 60 degree oven for 40 minutes to form an injection structure 321 of the cavity 1; Figure 8 As shown in (d), the mold 2 is used again. Figure 4 The cavity 2 is injected with thermosetting glue, and then cured in a 60 degree oven for 40 minutes to form an injection structure 322 of the cavity 2; the injection structures 321, 322, 323, and 324 together constitute the final injection structure 3. In the figure, A1 represents a sealing structure.

[0088] Embodiment 3

[0089] refer to Fig. 9 , this embodiment is to inject glue to obtain Figure 2 The glue injection structure 3. This embodiment first adopts method 3 to divide the obtained Figure 6 The cavity 1, cavity 2 and cavity 3 shown are as follows Figure 6 Three light-transmitting molds 1, 2, and 3 are made in the cavity.

[0090] When injecting glue, first use the first mold 1 pair Figure 6 The cavity 1 is injected with UV glue, such as Fig. 9 As shown in (a), after the glue is injected, UV curing is used to form the injection structure 331 of the cavity 1; Fig. 9 As shown in (b), the mold 2 is used again. Figure 6 The cavity 2 is injected with UV glue, and then cured with UV to form the injection structure 332 of the cavity 2; Fig. 9 As shown in (c), the mold is used again to Figure 6 The cavity 3 is injected with UV glue, and then cured with UV to form an injection structure 333 of the cavity 3; the injection structures 311, 312, and 333 together constitute the final injection structure 3. In the figure, A1 represents a sealing structure.

[0091] In summary, the multi-stage glue injection molding method of the present invention has the following beneficial effects: the present invention divides the complex glue injection structure of the product into multiple cavities from bottom to top, distinguishes the multiple cavities, and uses multiple glue injection molds corresponding to the multiple cavities to inject glue into the multiple cavities one by one in order from bottom to top, that is, multi-stage glue filling is realized, and the complex glue injection flow channel is simplified into multiple sections of simple flow channels, so that the original glue injection lack problem is effectively improved, and the product can achieve the appearance effect of no collapse and no glue lack, and at the same time it can improve and meet the strength problems and insufficient airtightness problems caused by lack of glue.

[0092] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal" and similar expressions used herein are for illustrative purposes only.

[0093] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0094] Terms including ordinal numbers such as "first", "second" and the like used in this specification may be used to describe various constituent elements, but these constituent elements are not limited by these terms. The purpose of using these terms is only to distinguish one constituent element from other constituent elements. For example, without departing from the scope of the present invention, the first constituent element may be named as the second constituent element, and similarly, the second constituent element may also be named as the first constituent element. The term "or / and" used herein includes any and all combinations of one or more related listed items.

[0095] In the specification provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0096] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those explicitly recited in each claim. More specifically, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present invention.

[0097] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A multi-stage glue injection molding method, applied to electronic products, wherein the cover of the electronic product comprises a concave surface and a flange connected to the top edge of the concave surface, and the method is used to inject glue on the flange and the concave surface, characterized in that: The method comprises: Before the glue injection, the glue injection flow channel corresponding to the glue injection structure to be finally formed is divided with the concave surface facing upward, and the glue injection flow channel is divided into a plurality of cavities from bottom to top; According to the injection flow channel division result, a plurality of injection molds corresponding to the plurality of cavities are manufactured; When injecting glue, the glue is injected into the multiple cavities one by one in a bottom-up order using a plurality of glue injection molds corresponding to the multiple cavities.

2. The multi-stage injection molding method according to claim 1, characterized in that: The injection mold corresponding to each cavity includes: a molding release surface corresponding to the dividing line of a cavity immediately above or conforming to the required shape of the product, a sealing structure pressed with the injection structure of a cavity immediately below or / and pressed with the product, and at least two glue inlet and outlet ports.

3. The multi-stage injection molding method according to claim 1, characterized in that: The process of dividing the injection flow channel specifically includes: dividing the injection flow channel into upper and lower cavities according to whether it is the appearance part of the injection structure that needs to be formed eventually, and the upper cavity forms the appearance part of the injection structure that needs to be formed eventually after injection of glue.

4. The multi-stage injection molding method according to claim 1, characterized in that: The process of dividing the glue injection channel specifically includes: intercepting a representative cross section of the glue injection channel perpendicular to the glue flow direction, taking the representative cross section as a target graphic, and executing a cavity processing strategy to divide the cavity.

5. The multi-stage injection molding method according to claim 4, characterized in that: The representative cross section is extracted by: Cutting a plurality of cross sections of the glue injection channel perpendicular to the glue flow direction, and selecting cross sections with large differences according to the area change of each cross section relative to the cross sections before and after it; For each screened cross section, the cross section is used as a target graphic to execute the cavity processing strategy to divide the cavity, and the cross section with the largest number of cavities is selected as the representative cross section.

6. The multi-stage injection molding method according to claim 4 or 5, characterized in that: The cavity processing strategy includes: determining the maximum inscribed circle within the current target graphic, determining a cavity dividing line based on the currently determined maximum inscribed circle, and if the injection channel still has a remaining area other than the already determined cavity, taking the remaining area as a new target graphic and executing the cavity processing strategy again.

7. The multi-stage injection molding method according to claim 6, characterized in that: The step of determining a cavity dividing line based on the currently determined maximum inscribed circle specifically includes: The diameter of the currently determined maximum inscribed circle is used as the characteristic size of the cavity to be determined next; Determine all available inflection points of the injection flow channel; For each available inflection point: take it as the first endpoint of the line segment, move the second endpoint of the line segment on the contour of the injection flow channel, if the length of the line segment when the second endpoint is on both sides of a certain position is longer than the length of the line segment at the certain position, take the certain position as the position of the second endpoint of the line segment, and take the line segment at this time as a target line; By comparing each of the target lines with the characteristic size, the target line that meets the requirements is selected as the dividing line of the cavity.

8. The multi-stage injection molding method according to claim 7, characterized in that: The step of comparing each of the target lines with the characteristic dimensions and selecting the target line that meets the requirements as the cavity dividing line specifically includes: The target lines whose lengths are greater than a preset ratio of the characteristic size are screened out, and only the target lines whose lengths are less than or equal to the preset ratio of the characteristic size are retained.

9. The multi-stage injection molding method according to claim 1, characterized in that: The method further includes: after each cavity is injected with glue, curing is first performed, and then the glue injection of a cavity immediately above is performed; or, after each cavity is injected with glue, curing is not performed, and the glue injection of a cavity immediately above is continued.

10. The multi-stage injection molding method according to claim 1, characterized in that: The mold is a mold suitable for thermosetting glue, or a UV light-transmitting mold suitable for UV curing glue.

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