Method for Controlling Glue Flow

Abstract

The present invention relates to the technical field of PCB manufacturing, and specifically discloses a method for controlling glue flow. The method for controlling glue flow includes opening a first window at the position of the bonding sheet corresponding to the stepped groove. A first adhesive layer is attached to the upper side of the position of the dielectric film corresponding to the stepped groove, and a second window is opened. The length of the second window is less than the length of the first window, and the width of the second window is less than the width of the first window. The side walls of the second window are cut to form two long-side wrapping parts and two short-side wrapping parts. The bonding sheet is placed on the dielectric film, and the two long-side wrapping parts and the two short-side wrapping parts are each folded 180° to form a bonding preform. The core board and the bonding preform are stacked in sequence and hot-pressed. The above method enables the inside of the second window of the bonding sheet to be wrapped. During the subsequent lamination with the core board, the glue flow of the bonding sheet is blocked by the dielectric film, thereby greatly reducing the possibility of the glue flow entering the bottom of the stepped groove formed by the steps and greatly improving the performance of the PCB.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB manufacturing, and particularly to a method for controlling glue flow. Background Art

[0002] There are usually two manufacturing processes for PCBs with stepped designs. One is the mechanical controlled-depth milling process to mill out the steps, which is simple but cannot accurately control the steps to the specified layer and is not applicable to PCBs with graphic designs at the bottom of the steps. The other is the lamination and embedding gasket process, which can meet the requirements of steps to the specified layer and can manufacture PCBs with graphic designs at the bottom of the steps. However, during the lamination process, if conventional adhesive sheets are used, it is difficult to control the glue flow, resulting in excessive glue flow and the problem of residual glue remaining at the bottom of the stepped grooves formed by the steps, thereby affecting the performance of the PCB.

[0003] Therefore, there is an urgent need to study a method for controlling glue flow to solve the problems of difficult glue flow control, excessive glue flow, and residual glue remaining at the bottom of the stepped grooves formed by the steps during the lamination process of conventional adhesive sheets. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for controlling glue flow to solve the problems of difficult glue flow control, excessive glue flow, and residual glue remaining at the bottom of the grooves during the lamination process of conventional adhesive sheets.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for controlling glue flow, which includes:

[0007] S1. Open a first window at the position of the adhesive sheet corresponding to the stepped groove;

[0008] S2. Stick a first adhesive layer on the upper side of the position of the dielectric film corresponding to the stepped groove, and open a second window. The length of the second window is less than that of the first window, and the width of the second window is less than that of the first window. Cut the side walls of the second window to form two long-side wrapping parts and two short-side wrapping parts;

[0009] S3. Place the adhesive sheet on the dielectric film, and fold each of the two long-side wrapping parts and the two short-side wrapping parts by 180° to form a pre-bonding sheet;

[0010] S4. Stack the core board and the pre-bonding sheet in sequence and perform high-temperature lamination.

[0011] Optionally, between S3 and S4, S31 is further included, that is, removing the part of the dielectric film outside the first window.

[0012] Optionally, perform a dotted-line pre-cut treatment on the dielectric film to form a pre-cut seam, and the projection of the first window on the dielectric film is located inside the pre-cut seam.

[0013] Optionally, before placing the adhesive sheet on the dielectric film, the dielectric film is placed on a support plate provided with a leaflet. After the leaflet is turned over by 180°, the long-side wrapping portion and the short-side wrapping portion are folded by 180°.

[0014] Optionally, the support plate is provided with adsorption holes for adsorbing the leaflet turned over by 180°.

[0015] Optionally, the adhesive sheet is provided with a first positioning hole, the dielectric film is provided with a second positioning hole, and the support plate is provided with a positioning pin that passes through the first positioning hole and the second positioning hole.

[0016] Optionally, in step S4, there are two core boards, which are respectively clamped on both sides of the bonding preform.

[0017] Optionally, after step S4, it further includes:

[0018] S5. A third window is opened in the core board.

[0019] Optionally, in step S4, there are at least three core boards, among which two core boards are hard boards and at least one core board is a soft board. There are at least two bonding preforms, among which the two hard boards are arranged on the outermost layers, and bonding preforms are provided between the hard board and the soft board and between any two adjacent soft boards.

[0020] Optionally, a third window is opened in at least one hard board.

[0021] The beneficial effects of the present invention are as follows:

[0022] The present invention provides a method for controlling glue flow. By opening a first window at the position of the adhesive sheet corresponding to the stepped groove, pasting a first adhesive layer on the upper side of the dielectric film corresponding to the stepped groove, and opening a second window, and folding the long-side wrapping portion and the short-side wrapping portion by 180°, the inner side of the second window of the adhesive sheet is wrapped. During the subsequent lamination with the core board, the glue flow of the adhesive sheet is blocked by the dielectric film, thereby greatly reducing the possibility of the glue flow entering the bottom of the stepped groove formed by the steps and improving the performance of the PCB. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the adhesive sheet in the embodiment of the present invention;

[0024] Figure 2 It is a schematic structural diagram of the dielectric film in the embodiment of the present invention;

[0025] Figure 3 It is a schematic structural diagram of the dielectric film, the first adhesive layer and the second adhesive layer in the embodiment of the present invention;

[0026] Figure 4Schematic diagram of the support plate and the hinge in the embodiment of the present invention;

[0027] Figure 5 Schematic side view structure diagram of the support plate and the hinge in the embodiment of the present invention;

[0028] Figure 6 Schematic diagram of the hinge in the initial position in the embodiment of the present invention;

[0029] Figure 7 Schematic diagram of the hinge rotated 180° in the embodiment of the present invention;

[0030] Figure 8 Schematic diagram of the bonding sheet and the dielectric film placed on the support plate in the embodiment of the present invention;

[0031] Figure 9 Schematic diagram of the inner side of the first window where the control dielectric film wraps the bonding sheet in the embodiment of the present invention;

[0032] Figure 10 Schematic diagram of the structure after the excess part of the dielectric film is removed through the pre-cut slit in the embodiment of the present invention;

[0033] Figure 11 Schematic diagram of the core board, the bonding preform and the positioning pin in the embodiment of the present invention;

[0034] Figure 12 Schematic diagram of the structure where two core boards are bonded by the bonding preform in the embodiment of the present invention;

[0035] Figure 13 Schematic diagram of the structure where the upper core board of the two core boards is provided with a third window in the embodiment of the present invention;

[0036] Figure 14 Schematic diagram of the structure where three core boards are bonded by the bonding preform in the embodiment of the present invention;

[0037] Figure 15 Schematic diagram of the structure where the upper and lower core boards of the three core boards are provided with third windows in the embodiment of the present invention;

[0038] Figure 16 Schematic diagram of the structure where the upper and lower core boards of the four core boards are provided with third windows in the embodiment of the present invention;

[0039] Figure 17 Flow chart of the method for controlling the flow of glue in the embodiment of the present invention.

[0040] In the figure:

[0041] 1. Bonding sheet; 11. First window; 12. First positioning hole;

[0042] 2. Dielectric film; 21. Second window; 22. Long-side wrapping part; 23. Short-side wrapping part; 24. Pre-cut slit; 25. Second positioning hole;

[0043] 3. First adhesive layer; 31. Second adhesive layer;

[0044] 4. Adhesive prefabricated sheet;

[0045] 5. Core board; 51. Third window;

[0046] 6. Support board; 61. Hinge; 62. Adsorption hole; 63. Positioning pin. Detailed implementation mode

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or only indicating that the first feature is at a higher horizontal height than the second feature. The first feature being "below", "beneath" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or only indicating that the first feature is at a lower horizontal height than the second feature.

[0049] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0050] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0051] As Figure 1-17 shown, this embodiment provides a method for controlling glue flow. The method for controlling glue flow includes the following steps:

[0052] Step 1: Open a first window 11 at the position corresponding to the stepped groove of the bonding sheet 1.

[0053] Step 2: Stick a first bonding layer 3 on the upper side of the position corresponding to the stepped groove of the dielectric film 2, and open a second window 21. The length of the second window 21 is less than the length of the first window 11, and the width of the second window 21 is less than the width of the first window 11. Cut the side walls of the second window 21 to form two long-side wrapping parts 22 and two short-side wrapping parts 23. Among them, the length of the dielectric film 2 is greater than the length of the first window 11, and the width of the dielectric film 2 is greater than the width of the first window 11.

[0054] Step 3: Place the bonding sheet 1 on the dielectric film 2, and fold each of the two long-side wrapping parts 22 and the two short-side wrapping parts 23 by 180° to form a bonding preform 4.

[0055] Step 4: Stack the core board 5 and the bonding preform 4 in sequence and perform high-temperature lamination.

[0056] By means of the above method, the inside of the second window 21 of the bonding sheet 1 is wrapped. During the subsequent lamination process with the core board 5, the glue flow of the bonding sheet 1 is blocked by the dielectric film 2, thereby greatly reducing the possibility of the glue flow entering the bottom of the stepped groove formed by the steps, and greatly improving the performance of the PCB.

[0057] Between Step 3 and Step 4, there is also Step 31 of removing the excess part of the dielectric film 2 outside the first window 11 to avoid the bonding sheet 1 so that the bonding sheet 1 can bond the upper and lower core boards 5. Specifically, perform a dotted-line pre-cut treatment on the dielectric film 2 to form a pre-cut seam 24. The projection of the contour line of the first window 11 on the dielectric film 2 is located inside the pre-cut seam 24. The pre-cut seam 24 is similar to the seam between the ticket and the stub of a torn ticket, which is convenient for tearing later to remove the excess dielectric film 2.

[0058] In step three, before placing the bonding sheet 1 on the dielectric film 2, the dielectric film 2 is placed on the support plate 6. The support plate 6 is provided with a leaf 61. By flipping the leaf 61, the leaf 61 can be flipped 180°, so that the long-side wrapping part 22 and the short-side wrapping part 23 are folded 180°. This setting makes it easy to fold the long-side wrapping part 22 and the short-side wrapping part 23. Among them, the flipping of the leaf 61 can be operated by a manipulator. Specifically, there are four leaves 61, corresponding to two long-side wrapping parts 22 and two short-side wrapping parts 23 respectively. The leaf 61 is of a plate-like structure and is bonded to the support plate 6 through a thin film structure, so that the leaf 61 can be freely folded.

[0059] To firmly wrap the bonding sheet 1 with the dielectric film 2, the support plate 6 is provided with adsorption holes 62 for adsorbing the leaf 61 that has been flipped 180°. By inhaling through the adsorption holes 62, the leaf 61 that has been flipped and pressed on the bonding sheet 1 is adsorbed, so that the leaf 61 presses the dielectric film 2, and the dielectric film 2 and the bonding sheet 1 are firmly bonded. Among them, suction holes are provided on the bonding sheet 1 opposite to the adsorption holes 62. After the bonding sheet 1 melts, the suction holes are automatically filled with flowing glue. In other embodiments, the adsorption holes 62 are located outside the bonding sheet 1. In another embodiment, the adsorption holes 62 may not be provided, and pressure is directly applied to the leaf 61 to firmly bond the dielectric film 2 and the bonding sheet 1.

[0060] In this embodiment, the leaf 61 is provided with an avoidance groove, and both the long-side wrapping part 22 and the short-side wrapping part 23 after being folded 180° are located in the avoidance groove, so that the leaf 61 can apply pressure evenly.

[0061] The bonding sheet 1 is provided with a first positioning hole 12, the dielectric film 2 is provided with a second positioning hole 25, and the support plate 6 is provided with a positioning pin 63. The positioning pin 63 passes through the first positioning hole 12 and the second positioning hole 25. This method makes the alignment of the dielectric film 2 and the bonding sheet 1 accurate and improves the accuracy of wrapping the bonding sheet 1. Among them, there are four positioning pins 63.

[0062] Specifically, there are four cutting seams between the two long-side wrapping parts 22 and the two short-side wrapping parts 23, and the four cutting seams are located at the four corners of the second window 21. In this embodiment, to avoid the situation of glue flowing at the four corners of the bonding preform 4 in the first window 11, in step three, after forming the bonding preform 4, a first bonding layer 3 is pasted on the upper side at the position corresponding to the stepped groove of the second dielectric film 2, and the second window 21 is opened. The length of the second window 21 is smaller than the length of the first window 11, and the width of the second window 21 is smaller than the width of the first window 11. The side walls of the second window 21 are cut to form four corner wrapping strips at the four corners, and the bonding preform 4 is placed on the second dielectric film 2, and the four corner wrapping strips are each folded 180°, and the gaps at the four corners of the bonding preform 4 are wrapped twice to form the final bonding preform 4. It should be noted that in this embodiment, since the first window 11 is quadrilateral, due to the existence of the corner wrapping strips, the projection of the first window 11 is octagonal microscopically. However, the width dimension of the corner wrapping strips can be set to be small, and only the gaps at the four corners of the bonding preform 4 need to be covered. The width dimension of the corner wrapping strips is one-tenth or even one-hundredth of one side length of the first window 11. The width dimension of the corner wrapping strips can be ignored compared with the side length of the first window 11. Therefore, overall, the projection of the first window 11 is still quadrilateral.

[0063] In step four, there are two core boards 5, which are respectively clamped on both sides of the bonding preform 4. The layout at this position makes the entire PCB have a hollow structure. Among them, the two core boards 5 are positioned by positioning pins 63.

[0064] A second bonding layer 31 is pasted on the lower side of the dielectric film 2. After the long-side wrapping part 22 and the short-side wrapping part 23 are folded, the second bonding layer 31 can be used to assist the bonding sheet 1 to bond the adjacent core boards 5. The materials of the first bonding layer 3 and the second bonding layer 31 can be the same, and both can be pure glue. The materials of the first bonding layer 3 and the second bonding layer 31 can also be different. Among them, the first bonding layer 3 is pure glue, and the material of the second bonding layer 31 is the same as that of the bonding sheet 1.

[0065] The method for controlling glue flow also includes step five of opening a third window 51 in the core board 5. With this process, the PCB has a step, and the third window 51 and the first window 11 and another core board 5 form a stepped groove.

[0066] In one embodiment, in step four, there are at least three core boards 5. Among them, two core boards 5 are rigid boards, and at least one core board 5 is a flexible board. There are at least two bonding preforms 4. Among them, the two rigid boards are arranged on the outermost layers, and bonding preforms 4 are arranged between the rigid board and the flexible board and between any two adjacent flexible boards. The layout at this position makes the entire PCB have two hollow structures.

[0067] A third window 51 is formed in at least one rigid board. In an embodiment of the present embodiment, a third window 51 is formed in one rigid board. The third window 51 corresponds to the first window 11. By means of this process, the PCB has a step and a stepped groove is formed. In another embodiment of the present embodiment, third windows 51 are formed in both the upper and lower rigid boards. Both of the third windows 51 correspond to the first window 11. By means of this process, the PCB has two steps and two stepped grooves are formed.

[0068] Exemplarily, the rigid boards, the bonding prefabricated sheets 4, the flexible board, the bonding prefabricated sheets 4 and the rigid boards are sequentially arranged from top to bottom. Third windows 51 are formed in both the topmost and bottommost rigid boards.

[0069] In another embodiment, there are four core boards 5, two of which are rigid boards and two are flexible boards. The two rigid boards are respectively arranged outside the two flexible boards. A bonding prefabricated sheet 4 is pasted between each of the core boards 5. This layout of positions makes the entire PCB have three hollow structures. Further, third windows 51 are formed in the upper and lower rigid boards. The third window 51 corresponds to the first window 11. In this embodiment, the first windows 11 of the three bonding prefabricated sheets 4 can be directly opposite in the vertical direction or can be staggeredly arranged. For the sake of easy understanding, the first windows 11 of the respective bonding prefabricated sheets 4 in the figure of this embodiment are directly opposite in the vertical direction.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to enumerate all the embodiments here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for controlling bleeding, characterized in that, Including: S1. A first window (11) is opened at the position of the adhesive sheet (1) corresponding to the stepped groove. S2. A first adhesive layer (3) is pasted on the upper side of the dielectric film (2) at the position corresponding to the stepped groove, and a second window (21) is opened at the position of the dielectric film (2) corresponding to the stepped groove. The length of the second window (21) is smaller than that of the first window (11), and the width of the second window (21) is smaller than that of the first window (11). The side walls of the second window (21) are cut to form two long-side wrapping parts (22) and two short-side wrapping parts (23). S3. The adhesive sheet (1) is placed on the dielectric film (2), and the two long-side wrapping parts (22) and the two short-side wrapping parts (23) are each folded by 180° to form an adhesive preform (4). S4. The core board (5) and the adhesive preform (4) are stacked in sequence and hot-pressed.

2. The method for controlling glue flow according to claim 1, wherein Between S3 and S4, S31 is further included, that is, a part of the dielectric film (2) outside the first window (11) is removed.

3. The method for controlling the flow of glue according to claim 2, wherein A dotted-line pre-cut treatment is performed on the dielectric film (2) to form a pre-cut seam (24), and the projection of the first window (11) on the dielectric film (2) is located inside the pre-cut seam (24).

4. The method for controlling glue flow according to claim 1, wherein Before the adhesive sheet (1) is placed on the dielectric film (2), the dielectric film (2) is placed on the support plate (6). The support plate (6) is provided with a hinge (61). After the hinge (61) is flipped by 180°, the long-side wrapping parts (22) and the short-side wrapping parts (23) are folded by 180°.

5. The method for controlling the flow of glue according to claim 4, wherein The support plate (6) is provided with adsorption holes (62) for adsorbing the hinge (61) flipped by 180°.

6. The method for controlling the flow of glue according to claim 1, characterized in that, The adhesive sheet (1) is provided with a first positioning hole (12), the dielectric film (2) is provided with a second positioning hole (25), and the support plate (6) is provided with a positioning pin (63). The positioning pin (63) passes through the first positioning hole (12) and the second positioning hole (25).

7. The method for controlling glue flow according to any one of claims 1-6, characterized in that, In step S4, there are two core boards (5), which are respectively clamped on both sides of the adhesive preform (4).

8. The method for controlling glue flow according to claim 7, wherein After step S4, the following is further included: S5. A third window (51) is opened in the core board (5).

9. The method for controlling glue flow according to any one of claims 1-6, characterized in that, In step S4, there are at least three core boards (5), among which two core boards (5) are hard boards, and at least one core board (5) is a soft board. There are at least two adhesive preforms (4). Among them, the two hard boards are arranged on the outermost upper layer and the outermost lower layer, and an adhesive preform (4) is provided between the hard board and the soft board and between any two adjacent soft boards.

10. The method for controlling the flow of glue according to claim 9, characterized in that, A third window (51) is opened in at least one hard board.

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