Method for solving the problem of exposed copper of the resist ink at the hole opening position of the double-sided flexible board via hole

Abstract

The application discloses a method for solving the problem of exposed copper of resist soldering ink at the position of the hole opening of a double-sided soft board through hole, and comprises the following steps: S1, cutting; S2, drilling; S3, electroplating; S4, circuit etching; S5, AOL; S6, pasting a first surface cover film; S7, silk printing resist soldering ink; and S8, pasting a second surface cover film. The method for solving the problem of exposed copper of resist soldering ink at the position of the hole opening of a double-sided soft board through hole adjusts the production process, pastes the cover film of the surface that needs to be printed with resist soldering ink first, and pastes the cover film of the other surface after resist soldering ink is completed, so that the conductive hole is a through hole structure when the silk printing ink is printed, and the silk printing resist soldering ink can be smoothly filled into the conductive hole, and the production test and demonstration show that the problem of exposed copper of resist soldering ink at the edge of the conductive hole in the resist soldering ink area can be solved by 100%, the resist soldering yield is high and stable, the method has the characteristics of high production efficiency, high yield and low cost, and can effectively solve the problem of exposed copper at the hole edge.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of circuit board production, in particular to a method for solving copper exposure of solder resist ink at a through-hole orifice position of a double-sided soft board. BACKGROUND

[0002] Because the conductive through-hole is in the silk-screen solder resist ink area of the double-sided soft board, after the covering film is attached, a blind hole structure is formed, and when the solder resist ink is silk-screened, the ink is scraped onto the blind hole, and due to factors such as small hole diameter (0.6 mm), air in the hole and tension of the ink itself, the ink cannot quickly flow into the hole, a bubble state is formed, and after the silk-screening, the ink at the hole edge starts to flow into the lower part of the hole in the static state, copper exposure without ink covering is formed at the hole edge, no solder resist ink covering is formed at the hole edge, and the functionality of an electronic product is affected. Figures 5-8 .

[0003] In the prior art, in order to solve the problem of copper exposure of solder resist ink at the hole edge, twice solder resist ink is currently used, and this method not only has high operation cost, but also has problems of poor quality and difficulty in controlling the thickness of the ink.

[0004] Therefore, the application provides a method for solving copper exposure of solder resist ink at a through-hole orifice position of a double-sided soft board, so as to solve the problem of copper exposure of solder resist ink at the hole edge in the background art. SUMMARY

[0005] The application aims to provide a method for solving copper exposure of solder resist ink at a through-hole orifice position of a double-sided soft board, so as to solve the problem of copper exposure of solder resist ink at the hole edge in the background art.

[0006] To achieve the above-mentioned purpose, the application provides the following technical scheme: a method for solving copper exposure of solder resist ink at a through-hole orifice position of a double-sided soft board, comprising the following steps:

[0007] S1, cutting: according to fixed specifications, a cutting device is used to cut a double-sided soft board with required specifications;

[0008] S2, drilling: according to specific requirements of the design position of the through hole of the double-sided soft board, a program of a numerical control drilling machine is accurately programmed, the position of the required hole is drilled on the cut double-sided soft board, and then the drilling is checked by comparing with a photo of the through hole, and when no deviation is found, the next process is entered;

[0009] S3, electroplating: also known as copper plating, which is an important link of the through hole method; copper is deposited on the hole wall through the method of electroplating, so as to ensure the conduction of the copper covering on both sides of the PCB and increase the thickness of the whole copper covering; after the copper deposition, the substrate is checked for defects such as "no copper in the hole, hole plugging and roughness";

[0010] S4, line etching: attach the etching template to the double-sided soft board, then put the double-sided soft board into the etching solution, so that the area to be etched is etched by chemical etching;

[0011] S5, AOL: using high-speed and high-precision visual processing technology to automatically detect various different mounting errors and welding defects on the double-sided soft board;

[0012] S6, paste the first side cover film: use the film coating equipment to coat the side that needs to print ink;

[0013] S7, silk printing solder resist ink: use silk printing equipment to print solder resist ink on the double-sided soft board;

[0014] S8, paste the second side cover film: use the film coating equipment to coat the other side of the double-sided soft board;

[0015] S9, chemical gold: a layer of metal film is plated on the surface of the double-sided soft board;

[0016] S10, text: print text on the circuit board;

[0017] S11, molding: the double-sided soft board is produced into a shape;

[0018] S12, paste FR4: paste the flame-resistant material grade code on the surface of the double-sided soft board;

[0019] S13, electrical measurement: ensure that the circuit connection on the double-sided soft board is correct, without open circuit or short circuit;

[0020] S14, appearance inspection / packaging.

[0021] Preferably, in step S4, the specific steps of etching include:

[0022] S41, design the circuit diagram according to the circuit requirements, which can be drawn using circuit design software. Attention should be paid to the circuit layout and component selection during design to ensure the circuit function and performance;

[0023] S42, clean the double-sided soft board and etch it with chemicals such as potassium ferrocyanide. After etching, the board needs to be cleaned;

[0024] S43, print the designed circuit diagram on the double-sided soft board, which can be printed using an inkjet printer or a laser printer. Before printing, the surface of the double-sided soft board needs to be coated with a copper film to protect the area that does not need to be etched;

[0025] S44, copy the printed circuit diagram through photosensitive dry film or photosensitive glue to make an etching template. The etching template needs to expose the area to be etched for etching treatment;

[0026] S45, the prepared etching template is pasted on the double-sided soft plate, and the plate is soaked in etching liquid, so that the area needing etching is etched by chemical etching, and the plate needs to be cleaned after etching.

[0027] Preferably, in step S7, the silk screen mesh used in the silk printing device is selected as 51T.

[0028] Preferably, in step S6, before coating, an acid plate grinding machine is used for acid plate grinding to remove oxides and impurity dust particles on the double-sided soft plate, so as to ensure the quality of subsequent silk printing.

[0029] Preferably, in step S7, before printing the solder resist ink, the solder resist ink needs to be pre-dried at a temperature of 70-90 DEG C for 30-50 minutes.

[0030] Preferably, the double-sided soft plate placing mechanism of the printing device in step S7 comprises a sleeve frame, an inner cavity is formed in the inner part of the sleeve frame, and a clamping groove is formed in each of the four corner parts of the sleeve frame.

[0031] Preferably, a side mounting block is fixedly connected to the middle part of each side of the sleeve frame, an installation hole is formed in the inner part of the side mounting block, and a threaded hole is formed in one end of the installation hole.

[0032] Preferably, an inner loading rack is arranged in the inner part of the inner cavity, a limiting block is fixedly connected to each of the four corner parts of the inner loading rack, and the limiting block is clamped with the clamping groove.

[0033] Preferably, an air passage is formed in the inner part of the inner loading rack, and a bottom loading groove is formed in the lower end of the inner loading rack.

[0034] Preferably, a through hole is formed in the upper end of the sleeve frame, the through hole is communicated with the air passage, a threaded loading hole is formed in the middle part of each side of one side of the lower end of the sleeve frame, an air inlet connecting pipe and an air outlet connecting pipe are respectively threadedly connected to the inner parts of the two threaded loading holes, and the threaded loading hole is communicated with the air passage.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] 1. By adjusting the production process, the covering film of the side needing to print the solder resist ink is pasted first, and the covering film of the other side is pasted after the solder resist ink is completed, so that the conductive hole is a through hole structure when the solder resist ink is printed, the solder resist ink can be smoothly filled into the conductive hole, and the problem of copper exposure at the hole edge of the solder resist ink area can be solved by 100%, the solder resist yield is high and stable, the production efficiency is high, the yield is high, the cost is low, and the problem of copper exposure at the hole edge can be effectively solved.

[0037] 2、Through the threaded hole and the installation hole, the installation can be installed in two ways of clamping and end fixing, which can make the installation more stable, and can limit the installation rod and the outer sleeve frame, to facilitate the subsequent installation and use, through the bottom installation groove and the limiting block, after the installation of the air inlet connecting pipe and the air outlet connecting pipe, the wire can be used to bind the pipeline under the inner loading frame, through the clamping between the limiting block and the clamping groove, and the gravity of the pipeline and the inner loading frame itself, the installation between the inner loading frame and the outer sleeve frame is more stable, and the design can limit the pipeline, which is convenient for the arrangement of the line;

[0038] 3、Through the through hole and the ventilation cavity, when in use, the hot gas needs to flow, the inner loading frame can be heated, in this way, after the double-sided soft plate is placed on the inner loading frame, the double-sided soft plate can be preheated, to facilitate the drying of the solder resist ink, reduce the drying time, at the same time, through the flow of gas, the air pressure in the ventilation cavity is low, when the double-sided soft plate is placed on the inner loading frame, it will be extruded by the pressure, so that the double-sided soft plate is attached to the inner loading frame, to facilitate the installation of the double-sided soft plate, and the damage to the double-sided soft plate is small, which ensures the integrity of the double-sided soft plate. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a flow chart of the method for solving the double-sided soft plate through hole orifice position solder resist ink copper exposure of the application;

[0040] Figure 2 It is a perspective view of the double-sided soft plate placing mechanism in the method for solving the double-sided soft plate through hole orifice position solder resist ink copper exposure of the application;

[0041] Figure 3 It is a perspective view of the outer sleeve frame in the method for solving the double-sided soft plate through hole orifice position solder resist ink copper exposure of the application;

[0042] Figure 4 It is an internal structure diagram of the inner loading frame in the method for solving the double-sided soft plate through hole orifice position solder resist ink copper exposure of the application;

[0043] Figure 5 It is a stack structure diagram before covering the cover film;

[0044] Figure 6 It is a stack structure diagram after covering the cover film;

[0045] Figure 7 It is a stack structure diagram when silk printing;

[0046] Figure 8 It is a stack structure diagram after silk printing.

[0047] In the figure:

[0048] 1, outer frame; 2, inner loading frame; 3, through hole; 4, side block; 5, mounting hole; 6, ventilation cavity; 7, clamping groove; 8, limiting block; 9, air inlet connecting pipe; 10, air outlet connecting pipe; 11, inner cavity; 12, bottom loading groove; 13, threaded hole; 14, threaded loading hole. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. Embodiment one

[0050] Referring to Figure 1 As shown in a method for solving the problem of solder resist ink copper exposure at the hole opening position of a double-sided soft board, comprising the following steps:

[0051] Step one, cutting: according to fixed specifications, using a cutting device, cutting the required specifications of the double-sided soft board;

[0052] Step two, drilling: according to the specific requirements of the double-sided soft board through hole design position, accurately programming the numerical control drilling machine, drilling the required hole position on the cut double-sided soft board, then checking with the through hole photo, confirming no deviation, then entering the next process;

[0053] Step three, electroplating: also known as copper plating, is an important link of the through hole method; through the method of electroplating, copper is deposited on the hole wall to ensure the conduction of the copper on both sides of the PCB, and at the same time increase the thickness of the whole copper; after copper deposition, check the substrate for "no copper in the hole, plug hole, roughness" and other defects;

[0054] Step four, circuit etching: the specific steps include:

[0055] 1) Design the circuit diagram according to the circuit requirements, which can be drawn using circuit design software. Attention should be paid to the circuit layout and component selection during design to ensure circuit function and performance;

[0056] 2) Clean the double-sided soft board and use potassium ferrocyanide and other chemicals for etching treatment. After etching, the board needs to be cleaned;

[0057] 3) Print the designed circuit diagram on the double-sided soft board, which can be printed using an inkjet printer or a laser printer. Before printing, the double-sided soft board surface needs to be coated with a copper clad laminate to protect the area that does not need to be etched;

[0058] 4), the printed circuit diagram is copied through photosensitive dry film or photosensitive glue, and an etching template is made, and the etching template needs to expose the area to be etched to the outside, so as to be etched;

[0059] 5), the prepared etching template is attached to the double-sided soft plate, and the oxide and impurity dust particles on the double-sided soft plate are removed, so that the quality of subsequent silk printing is ensured, and the plate is soaked in etching liquid, so that the area to be etched is etched by chemical medicine, and the plate is cleaned after etching;

[0060] Step five, AOL: using high-speed and high-precision visual processing technology to automatically detect various different mounting errors and welding defects on the double-sided soft plate;

[0061] Step six, paste the first cover film: before laminating, an acid plate grinding machine is used for acid plate grinding, and then a laminating device is used to laminate the side to be printed with ink;

[0062] Step seven, silk printing of solder resist ink: before printing the solder resist ink, the solder resist ink needs to be pre-dried at a temperature of 70-90 DEG C for 30-50 minutes, and the solder resist ink is printed on the double-sided soft plate by using a silk printing device;

[0063] Step eight, paste the second cover film: use a laminating device to laminate the other side of the double-sided soft plate;

[0064] Step nine, gold plating: a layer of metal film is plated on the surface of the double-sided soft plate;

[0065] Step ten, text: printing text on the circuit board;

[0066] Step eleven, molding: the double-sided soft plate is produced and molded;

[0067] Step twelve, paste FR4: paste the fire-resistant material grade code on the surface of the double-sided soft plate;

[0068] Step thirteen, electrical measurement: ensure that the circuit connection on the double-sided soft plate is correct, without open circuit or short circuit;

[0069] Step fourteen, appearance inspection / packaging.

[0070] In the application, by adjusting the production process, the cover film of the side to be printed with solder resist ink is pasted first, and the cover film of the other side is pasted after the solder resist ink is completed, so that the conductive hole is a through hole structure when the solder resist ink is silk printed, the solder resist ink can be smoothly filled into the conductive hole, and the problem of copper exposure at the hole edge in the solder resist ink area can be solved by 100%, the solder resist yield is high and stable, has the characteristics of high production efficiency, high yield and low cost, and can effectively solve the problem of copper exposure at the hole edge. Example two

[0071] Figures 2-4 As shown, the double-sided soft plate placing mechanism of the printing device in step S7 comprises a sleeve frame 1, an inner cavity 11 is formed in the inside of the sleeve frame 1, a clamping groove 7 is formed in each of the four corner portions of the sleeve frame 1, a side mounting block 4 is fixedly connected to the middle portion of each of the two sides of the sleeve frame 1, an installation hole 5 is formed in the inside of the side mounting block 4, a threaded hole 13 is formed in one end of the installation hole 5, a threaded groove needs to be formed in the end of the driving rod connected with the installation hole 5, an inner loading rack 2 is arranged in the inside of the inner cavity 11, a limiting block 8 is fixedly connected to each of the four corner portions of the inner loading rack 2, the limiting block 8 is clamped with the clamping groove 7, an air passage 6 is formed in the inside of the inner loading rack 2, a bottom loading groove 12 is formed in the lower end of the inner loading rack 2, a through hole 3 is formed in the upper end of the sleeve frame 1, the through hole 3 is communicated with the air passage 6, a threaded loading hole 14 is formed in the middle portion of each of the two sides of the lower end of the sleeve frame 1, an air inlet connecting pipe 9 and an air outlet connecting pipe 10 are respectively screwed in the inner portions of the two threaded loading holes 14, the threaded loading hole 14 is communicated with the air passage 6. The threaded loading hole 14, the air inlet connecting pipe 9 and the air outlet connecting pipe 10 are installed and fixed in a threaded manner, the inner loading rack 2 is integrally produced by pouring metal material, the upper half of the inner loading rack 2 is first produced, then the lower half of the inner loading rack 2 is produced, and then the upper and lower portions of the inner loading rack 2 are fixed.

[0072] In the application, the threaded hole 13 and the installation hole 5 are arranged, so that the installation can be performed in a clamping and end fixing manner during installation, the installation is stable, the installation rod and the sleeve frame 1 can be limited, subsequent installation and use are facilitated, the bottom loading groove 12 and the limiting block 8 are arranged, after the air inlet connecting pipe 9 and the air outlet connecting pipe 10 are installed, the pipes can be bound below the inner loading rack 2 by using a wire, the clamping between the limiting block 8 and the clamping groove 7 and the gravity of the pipes and the inner loading rack 2 can make the installation between the inner loading rack 2 and the sleeve frame 1 stable, the design can limit the pipes and facilitate the arrangement of the lines, the through hole 3 and the air passage 6 are arranged, during use, hot air needs to flow, the inner loading rack 2 can be heated, in this way, the double-sided soft plate can be preheated after being placed on the inner loading rack 2, the drying of the solder resist ink is facilitated, the drying time is reduced, the design can make the air pressure in the air passage 6 low, so that the double-sided soft plate is extruded by the pressure when being placed on the inner loading rack 2, the double-sided soft plate is attached to the inner loading rack 2, the installation of the double-sided soft plate is facilitated, the damage to the double-sided soft plate is small, and the integrity of the double-sided soft plate is ensured.

[0073] The working principle of the present application: when installing the outer frame 1, insert the driving rod into the installation hole 5, then use screws to install the side block 4 with the driving rod, then install the air inlet connecting pipe 9 and the air outlet connecting pipe 10 into the threaded loading hole 14, then install the inner loading frame 2 into the inner loading cavity 11, and then clamp the limiting block 8 into the clamping groove 7, in this way, the initial fixation is completed, then install the gas conveying equipment with the air outlet connecting pipe 10 and the air inlet connecting pipe 9 respectively, the air flow out of the air outlet connecting pipe 10 is greater than the air flow into the air inlet connecting pipe 9, then use the wire to pass through the bottom groove 12 to bind the pipe under the inner loading frame 2, in this way, the weight of the inner loading frame 2 is increased, the extrusion degree of the inner loading frame 2 to the outer frame 1 is increased, and the installation is completed, when using, open the gas conveying equipment, the hot gas flows in 15, the inner loading frame 2 is heated, then place the double-sided soft plate on the inner loading frame 2, enter the gas through the through hole 3, adsorb the double-sided soft plate, the heat on the inner loading frame 2 is conducted to the double-sided soft plate, the double-sided soft plate is preheated, then start the driving rod, move the outer frame 1 into the printing equipment, and print the double-sided soft plate.

[0074] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to part of the technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for solving the problem of copper exposure in solder mask ink at the through-hole opening of double-sided flexible circuit board, characterized in that: The following steps are involved: S1. Cutting: Use the cutting device to cut out the double-sided flexible board of the required specifications according to the fixed specifications; S2. Drilling: According to the specific requirements of the through-hole design position of the double-sided flexible board, the CNC drilling machine program is accurately written to drill the required hole positions on the cut double-sided flexible board. Then, the holes are compared with the photos of the through-holes to confirm that there is no deviation before entering the next process. S3. Electroplating: Also known as copper electroplating, it is an important step in the through-hole method. Copper is deposited on the hole wall by electroplating to ensure the conductivity of the copper on both sides of the PCB and increase the thickness of the entire copper. After copper deposition, check whether the substrate has any defects such as "no copper in the hole, plugged hole, roughness"; S4, circuit etching: attach an etching template to the double-sided flexible board, then place the double-sided flexible board in the etching solution, and let the area to be etched be etched away by chemicals; S5, AOL: Use high-speed and high-precision visual processing technology to automatically detect various placement errors and welding defects on double-sided flexible boards; S6. Apply the first covering film: Use laminating equipment to laminate the side that needs printing ink; S7, Silk screen solder mask ink: Use silk screen printing equipment to print solder mask ink on double-sided flexible circuit board; S8, apply the second side cover film: use the laminating equipment to laminate the other side of the double-sided flexible board; S9, gold plating: a layer of metal film is plated on the surface of the double-sided flexible circuit board; S10, text: printing text on the circuit board; S11, Molding: Double-sided soft board production molding; S12, FR4: affix the flame retardant material grade code to the surface of the double-sided flexible board; S13, electrical test; ensure that the circuit connections on the double-sided flexible board are correct and there are no open circuits or short circuits; S14. Appearance inspection / packaging.

2. A method for solving the problem of exposed copper in solder mask ink at the through-hole opening of a double-sided flexible circuit board according to claim 1, characterized in that: In step S4, the specific steps of etching include: S41. Design a circuit diagram based on circuit requirements and use circuit design software to draw it. Pay attention to circuit layout and component selection during design to ensure circuit functionality and performance. S42. Clean the double-sided flexible board and etch it with potassium ferrocyanide. Clean the board after etching. S43. Print the designed circuit diagram onto a double-sided flexible circuit board using an inkjet printer or a laser printer. Before printing, the surface of the double-sided flexible circuit board needs to be coated with a copper film to protect the areas that do not need to be etched. S44, replicating the printed circuit diagram using a photosensitive dry film or photosensitive adhesive to produce an etching template. The etching template needs to expose the area to be etched to facilitate etching. S45. Stick the prepared etching template on the double-sided soft board and soak it in the etching solution to allow the area to be etched by the chemicals. After etching, the board needs to be cleaned.

3. The method for solving the problem of exposed copper in solder mask ink at the through-hole opening of double-sided flexible circuit board according to claim 1, characterized in that: In step S7, the specification of the screen printing mesh used in the screen printing equipment is selected to be 51T.

4. The method for solving the problem of exposed copper in solder mask ink at the through-hole opening of double-sided flexible circuit board according to claim 1, characterized in that: In step S6, before lamination, a grinding machine is used to perform acid grinding to remove oxides and impurity dust particles on the double-sided flexible board, thereby ensuring the quality of subsequent silk screen printing.

5. The method for solving the problem of exposed copper in solder mask ink at the through-hole opening of double-sided flexible circuit board according to claim 1, characterized in that: In step S7, before printing the solder resist ink, the solder resist ink needs to be pre-dried, with a pre-drying temperature of 70° C. to 90° C. and a pre-drying time of 30 min to 50 min.

6. The method for solving the problem of exposed copper in solder mask ink at the through hole opening of double-sided flexible circuit board according to claim 1, characterized in that: The double-sided soft board placement mechanism includes a printing device in step S7, wherein the double-sided soft board placement mechanism includes an outer shell frame (1), an inner cavity (11) is provided inside the outer shell frame (1), and four corners of the outer shell frame (1) are provided with snap-in grooves (7).

7. A method for solving the problem of exposed copper in solder mask ink at the through hole opening of a double-sided flexible circuit board according to claim 6, characterized in that: The middle of both sides of the outer shell frame (1) are fixedly connected with side mounting blocks (4), the inside of the side mounting blocks (4) is provided with mounting holes (5), and one end of the mounting holes (5) is provided with threaded holes (13).

8. The method for solving the problem of exposed copper in solder mask ink at the through-hole opening of double-sided flexible circuit board according to claim 7, characterized in that: An inner loading rack (2) is provided inside the inner loading cavity (11), and the four corners of the inner loading rack (2) are fixedly connected with limiting blocks (8), and the limiting blocks (8) are clamped with the clamping grooves (7).

9. The method for solving the problem of exposed copper in solder mask ink at the through-hole opening of double-sided flexible circuit board according to claim 8, characterized in that: A ventilation cavity (6) is provided inside the inner loading frame (2), and a bottom mounting groove (12) is provided at the lower end of the inner loading frame (2).

10. A method for solving the problem of exposed copper in solder mask ink at the through-hole opening of a double-sided flexible circuit board according to claim 9, characterized in that: A through hole (3) is provided at the upper end of the outer jacket frame (1), and the through hole (3) is communicated with the ventilation cavity (6). Threaded loading holes (14) are provided on both sides of the middle portion of one side of the lower end of the outer jacket frame (1), and the interiors of the two threaded loading holes (14) are respectively threadedly connected with an air inlet connecting pipe (9) and an air outlet connecting pipe (10), and the threaded loading holes (14) are communicated with the ventilation cavity (6).

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