Device for horizontal electroplating of PCB (Printed Circuit Board) and method for horizontal electroplating of PCB

Abstract

The invention provides a device for horizontal electroplating of a PCB and a method for horizontal electroplating of the PCB.The device for horizontal electroplating of the PCB comprises a plated plate conveying belt, the two sides, perpendicular to the direction of the plated plate conveying belt, of the plated plate conveying belt are each provided with at least one conductive roller, and a conductive shaft core is arranged at the position of a center shaft of each conductive roller in a penetrating mode; the conductive shaft core is connected with a power supply; the conductive roller is also provided with at least three movable conductive thimbles; the movable conductive ejector pin is arranged in the circumferential surface direction of the conductive roller along the conductive axis; and at least three movable conductive thimbles are distributed, so that in the rolling process of the conductive roller, at least one movable conductive thimble is connected with the conductive shaft core and the plated plate conveying belt on each of the two sides of the plated plate conveying belt. The conductive mode of traditional horizontal electroplating is simplified, a conductive clamp is omitted, and the cost is reduced. The conductive mode of the device is suitable for a hard board and a flexible board, boards with different thicknesses can be considered, and the current distribution of the board surface can be improved at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of electroplating, and relates to a device for horizontal electroplating of a PCB and a method for horizontal electroplating of a PCB. Background Art

[0002] Printed Circuit Board (PCB) electroplating refers to the process of covering the surface of the circuit board with a layer of metal film. This metal film is usually made of conductive materials such as copper, nickel, and gold. It is designed to enhance the conductivity of the circuit board and protect and beautify the circuit board. Through the electroplating process, the metal layer on the surface of the circuit board can be evenly distributed, thereby improving the reliability and stability of the circuit board.

[0003] The advantages of PCB electroplating are mainly reflected in the following aspects: Excellent conductivity: The electroplating layer can significantly improve the conductivity of the circuit board, reduce resistance and signal transmission loss, and improve the transmission efficiency of the circuit board. Good corrosion resistance: The electroplating layer can effectively prevent the surface of the circuit board from being oxidized or corroded, thereby extending the service life of the circuit board. Good solderability: The electroplating layer can enhance the welding performance of the circuit board, improve the quality of the welding point, and reduce the welding defect rate. Aesthetics: The electroplating layer can make the surface of the circuit board smoother and brighter, and improve the overall appearance quality of the product.

[0004] The main methods of PCB electroplating commonly used in the prior art include immersion plating, spray plating and brush plating.

[0005] Immersion plating: The circuit board is completely immersed in the plating solution containing metal ions. The metal ions are deposited on the surface of the circuit board to form a metal film through the action of electric current. Immersion plating has the advantages of simple operation and low cost, but there may be problems with uneven distribution of the metal layer. Spraying: The plating solution is sprayed on the surface of the circuit board with a spray gun. By controlling the moving speed and angle of the spray gun, the metal layer is evenly distributed. Spraying is suitable for occasions with high requirements for the thickness and distribution of the metal layer. Brush plating: Use a brush to apply the plating solution to the surface of the circuit board, and the metal ions are deposited on the surface of the circuit board through the friction of the brush. Brush plating is suitable for electroplating local areas.

[0006] CN117241478A discloses a PCB double-sided and multi-layer board horizontal electroplating process, which includes the following steps: a. Pretreatment: cleaning the upper and lower surfaces of the PCB board and multiple through holes and blind holes on the PCB board; b. Metal deposition: copper deposition of multiple through holes and blind holes on the PCB board; c. Copper plating: electroplating the through holes and blind holes after copper deposition; d. Post-treatment: cleaning the PCB board.

[0007] CN115094500A discloses a device and method for horizontal copper electroplating, which includes: a plurality of electroplating tanks, wherein an object to be plated, which serves as an electroplating cathode, enters each electroplating tank in turn under the traction of a driving device to complete the electroplating operation; a plurality of electroplating anodes are arranged in each of the electroplating tanks, and an ion membrane capable of preventing bubbles from passing through is arranged between the object to be plated and the electroplating anode; in each of the electroplating tanks, the object to be plated is parallel to the electroplating anode, and the ion membrane has a set inclination angle relative to the electroplating anode; and the inclination direction of the ion membrane in at least one of the plurality of electroplating tanks is opposite to that of the ion membranes in the remaining electroplating tanks.

[0008] The conductive method of horizontal electroplating of PCB described in the above scheme is to conduct electricity by clamping one side of the PCB with a conductive clamp, which results in that the current horizontal electroplating line cannot produce electroplated winding boards. At the same time, the one-sided conduction will cause uneven current distribution of the whole board. Summary of the invention

[0009] The purpose of the present invention is to provide a device for horizontal electroplating of PCB and a method for horizontal electroplating of PCB. The present invention simplifies the conventional conductive method of horizontal electroplating, eliminates the conductive clip, and reduces the cost. The conductive method of the device is suitable for rigid boards and flexible boards, can take into account boards of different thicknesses, and can improve the current distribution on the board surface.

[0010] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a device for horizontal electroplating of PCBs, the device for horizontal electroplating of PCBs comprising a plated plate conveyor belt;

[0012] At least one conductive roller is respectively arranged on both sides of the plated plate conveyor belt perpendicular to the direction of the plated plate conveyor belt, a conductive shaft core is passed through the central axis of the conductive roller, and the conductive shaft core is connected to a power source;

[0013] The conductive roller is also provided with at least three movable conductive ejectors; the movable conductive ejectors are arranged along the conductive axis toward the circumferential surface of the conductive roller;

[0014] The distribution of the at least three movable conductive pins ensures that when the conductive roller is rolling, at least one movable conductive pin on each side of the plate-plating conveyor belt connects the conductive shaft core and the plate-plating conveyor belt.

[0015] Compared with the traditional PCB horizontal electroplating device, the device for PCB horizontal electroplating described in the present invention eliminates the conductive clamp and uses the roller itself to conduct electricity, thereby achieving large-area multi-point conductivity of the entire board, making the current distribution uniform. The conductive roller tightly presses the electroplated board to conduct electricity while transmitting it, which can not only perform electroplating production on hard boards, but also realize electroplating production on flexible boards.

[0016] The number of directions of the conductive roller of the present invention refers to the number of directions in which the movable conductive pins point outward from the axis center on the cross section of the conductive roller. For example, movable conductive pins are arranged in three directions of the conductive roller, that is, three pins pointing outward from the axis center in different directions are arranged on the cross section of the conductive roller.

[0017] Preferably, the length of the movable conductive ejector pin is a, the distance from the conductive axis to the circumferential surface of the conductive roller is b, and a=b.

[0018] Preferably, the movable conductive ejector pin is connected to the conductive axis through a conductive elastic component.

[0019] Preferably, the conductive elastic component comprises a conductive spring.

[0020] The movable conductive ejector pin of the present invention is embedded in the conductive roller and is tightly combined with the conductive roller to prevent the plating solution from penetrating into the roller. The movable conductive ejector pin can rebound through the elastic component inside. During the production process, when the conductive roller rotates and transmits, the movable conductive ejector pin contacts the plated board, and the movable conductive ejector pin is squeezed by the plated board, and the ejector pin is pressed into the roller. After the plated board passes through the roller, the movable conductive ejector pin bounces up and further contacts the plated board until the next conductive ejector pin contacts the plated board, so that at least one ejector pin contacts the plated board, ensuring continuous power supply.

[0021] Preferably, the distance between two adjacent conductive rollers is 1 cm to 20 cm, for example, 1 cm, 5 cm, 10 cm, 15 cm or 20 cm, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, movable conductive pins are arranged in 3 to 8 directions of the conductive roller, for example, 3, 4, 5, 6, 7 or 8, etc., not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0023] During the movement of the roller of the present invention, each roller provided with a conductive ejector pin progressively rotates a certain angle during the movement, and the conductive elastic component can control the conductive ejector pin to protrude from the roller, so as to ensure that the PCB is always contacted by the ejector pin for conduction during the rolling transmission of the roller, and the coating film will not be punctured due to the ejector pin being too long.

[0024] The conductive roller of the present invention is provided with movable conductive ejectors in 3 to 8 directions, that is, 3 to 8 ejectors pointing outward from the axis in different directions are provided on the cross section of the conductive roller.

[0025] Preferably, the number of movable conductive pins arranged in each direction of the conductive roller is 3 to 30, for example, 3, 5, 10, 20 or 30, etc., and is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] The number of movable conductive pins arranged in each direction of the conductive roller of the present invention is 3 to 30, and in one roller, 3 to 30 movable conductive pins are arranged in parallel in each direction.

[0027] Preferably, the device for horizontal electroplating of PCB further comprises an insulating roller.

[0028] Preferably, the insulating roller is arranged on the plated plate conveyor belt and is located on the opposite side of the conductive roller.

[0029] Preferably, an insulating axis is arranged at the center of the insulating roller.

[0030] In the device for horizontal electroplating of PCB described in the present invention, one of the conductive rollers located on both sides of the same position of the plated plate conveyor belt can be an insulating roller. The insulating roller only plays a role of transmission and can be adjusted according to actual needs.

[0031] Preferably, the conductive axis is connected to the cathode of the power supply.

[0032] In a second aspect, the present invention provides a method for horizontal electroplating of a PCB, the method using the apparatus for horizontal electroplating of a PCB as described in the first aspect, the method comprising the following steps:

[0033] The plated plate is placed on the plated plate conveyor belt, and the conductive axis of each conductive roller is connected to the cathode of the power supply. When the power supply is turned on, the plated plate conveyor belt starts to convey the plate for horizontal electroplating.

[0034] Preferably, the current density of the energized current is 10ASF to 70ASF, for example, 10ASF, 20ASF, 30ASF, 40ASF, 50ASF, 60ASF or 70ASF, etc. ASF refers to Amperes per Square Foot.

[0035] Preferably, the conveying speed of the plate-plating conveyor belt is 0.3 m / min to 3.0 m / min, for example, 0.3 m / min, 0.5 m / min, 1 m / min, 2 m / min or 3 m / min.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention simplifies the traditional horizontal electroplating conductive method, eliminates the conductive clip, and reduces costs. This conductive method is suitable for hard boards and flexible boards, can take into account boards of different thicknesses, and can improve the current distribution on the board surface.

[0038] (2) The copper thickness of the electroplated layer on the surface of the electroplated part obtained by using the PCB horizontal electroplating device of the present invention can reach a maximum difference of less than 5 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of a device for horizontal electroplating of PCBs provided in Example 1 of the present invention, wherein 1 is a conductive axis, 2 is a movable conductive ejector pin, 3 is a conductive roller, and 4 is a plated plate conveyor belt.

[0040] Figure 2 It is a cross-sectional schematic diagram of an apparatus for horizontal electroplating of PCBs provided in Example 1 of the present invention, wherein 1 is a conductive axis, 2 is a movable conductive ejector pin, 3 is a conductive roller, 4 is a plated plate conveyor belt, 5 is an insulating roller, and 6 is an insulating axis.

[0041] Figure 3 This is a schematic diagram of a device for horizontal electroplating of PCBs provided in Example 2 of the present invention, wherein 1 is a conductive axis, 2 is a movable conductive ejector pin, 3 is a conductive roller, and 4 is a plated plate conveyor belt.

[0042] Figure 4 It is a cross-sectional schematic diagram of a device for horizontal electroplating of PCBs provided in Example 2 of the present invention, wherein 1 is a conductive axis, 2 is a movable conductive ejector pin, 3 is a conductive roller, and 4 is a plated plate conveyor belt. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0044] Example 1

[0045] This embodiment provides a device for horizontal electroplating of PCB. The schematic diagram of the device for horizontal electroplating of PCB is shown in FIG. Figure 1 As shown, the cross-sectional schematic diagram of the device for horizontal electroplating of PCB is as shown Figure 2 As shown:

[0046] The device for horizontal electroplating of PCBs comprises a plate conveyor belt 4, and at least one conductive roller 3 is independently arranged on both sides of the plate conveyor belt 4. A conductive axis 1 and a movable conductive ejector pin 2 are arranged inside the conductive roller 3, and the conductive axis 1 is connected to a power source. The conductive axis 1 is arranged at the center of the conductive roller 3, and the movable conductive ejector pin 2 is evenly arranged along the conductive axis 1 toward the circumferential surface of the conductive roller 3;

[0047] Among them, movable conductive ejector pins 2 are arranged in five directions of the conductive roller, and during the rolling process of the conductive roller 3, the movable conductive ejector pin 2 in one direction of at least one conductive roller 3 on both sides of the plate conveyor belt 4 connects the conductive axis 1 and the plate conveyor belt 4;

[0048] The length of the movable conductive pin 2 is a, the distance from the conductive axis 1 to the circumference of the conductive roller 3 is b, a=b, and a spring is arranged between the movable conductive pin 2 and the conductive axis 1. During the rolling process of the conductive roller 3, the movable conductive pin 2 at the intersection of the conductive roller 3 and the plate conveyor belt 4 contacts the conductive axis 1 for conduction, and the other movable conductive pins 2 do not contact the conductive axis 1;

[0049] The distance between two adjacent conductive rollers is 5 cm, and the number of movable conductive pins arranged in each direction of the conductive roller is 10;

[0050] The PCB horizontal electroplating device also includes an insulating roller 5, which is arranged on the opposite side of the conductive roller 3, and an insulating axis 6 is arranged at the center of the insulating roller 5 (because the insulating roller 5 has no ejector pin and the position of the insulating axis 6 is Figure 1 The center coincides with the conductive axis 1, so Figure 1 Therefore, the position of the insulating roller 5 is shown in Figure 2 );

[0051] The conductive axis 1 is connected to the cathode of the power supply.

[0052] Example 2

[0053] This embodiment provides a device for horizontal electroplating of PCB. The schematic diagram of the device for horizontal electroplating of PCB is shown in FIG. Figure 3 As shown, the cross-sectional schematic diagram of the device for horizontal electroplating of PCB is as shown Figure 4 As shown:

[0054] The device for horizontal electroplating of PCB includes a plate conveyor belt 4, at least one conductive roller 3 is independently arranged on both sides of the plate conveyor belt 4, a conductive axis 1 and a movable conductive ejector pin 2 are arranged inside the conductive roller 3, and the conductive axis 1 is connected to a power source. The conductive axis 1 is arranged at the center of the conductive roller 3, and the movable conductive ejector pin 2 is evenly arranged along the conductive axis 1 toward the circumferential surface of the conductive roller 3;

[0055] Among them, movable conductive ejector pins 2 are arranged in five directions of the conductive roller, and during the rolling process of the conductive roller 3, the movable conductive ejector pin 2 in one direction of at least one conductive roller 3 on both sides of the plate conveyor belt 4 connects the conductive axis 1 and the plate conveyor belt 4;

[0056] The length of the movable conductive pin 2 is a, the distance from the conductive axis 1 to the circumference of the conductive roller 3 is b, a=b, and a spring is arranged between the movable conductive pin 2 and the conductive axis 1. During the rolling process of the conductive roller 3, the movable conductive pin 2 at the intersection of the conductive roller 3 and the plate conveyor belt 4 contacts the conductive axis 1 for conduction, and the other movable conductive pins 2 do not contact the conductive axis 1;

[0057] The distance between two adjacent conductive rollers is 3 cm, and the number of movable conductive pins arranged in each direction of the conductive roller is 5;

[0058] The conductive axis 1 is connected to the cathode of the power supply.

[0059] Application Example 1

[0060] This application example provides a method for horizontal electroplating of a PCB, the method using the device for horizontal electroplating of a PCB described in Example 1, the method comprising the following steps:

[0061] After pre-treatment of degreasing - water washing - water washing - micro-etching - water washing - water washing - acid washing, the plated plate is placed on a plated plate conveyor belt, and the conductive axis of each conductive roller is connected to the cathode of the power supply. The power supply passes a current of 20ASF, and the plated plate conveyor belt is transported at a speed of 0.8m / min for horizontal copper electroplating.

[0062] Application Example 2

[0063] This application example provides a method for horizontal electroplating of a PCB, the method using the device for horizontal electroplating of a PCB described in Example 2, the method comprising the following steps:

[0064] After pre-treatment of degreasing - water washing - water washing - micro-etching - water washing - water washing - acid washing, the plated plate is placed on a plated plate conveyor belt, and the conductive axis of each conductive roller is connected to the cathode of the power supply. The power supply passes a current of 12ASF, and the plated plate conveyor belt is transported at a speed of 0.3m / min for horizontal copper electroplating.

[0065] Application Example 3

[0066] This application example provides a method for horizontal electroplating of a PCB, the method using the device for horizontal electroplating of a PCB described in Example 2, and the method comprising the following steps:

[0067] After the plated plates are pre-treated with degreasing, water washing, water washing, micro-etching, water washing, water washing and pickling, they are placed on a plated plate conveyor belt. The conductive axis of each conductive roller is connected to the cathode of a power supply. The power supply passes a current of 70ASF, and the plated plate conveyor belt is transported at a speed of 3m / min for horizontal copper electroplating.

[0068] Application Example 4

[0069] The only difference between this application example and application example 1 is that the current density of the power supply is 80ASF, and the other conditions and parameters are exactly the same as those of application example 1.

[0070] Application Example 5

[0071] The only difference between this application example and application example 1 is that the current density of the power supply is 5ASF, and the other conditions and parameters are exactly the same as those of application example 1.

[0072] Application Example 6

[0073] The only difference between this application example and application example 1 is that the plated plate conveyor belt is transported at a speed of 4 m / min, and the other conditions and parameters are exactly the same as those in application example 1.

[0074] Application Example 7

[0075] The only difference between this application example and application example 1 is that the plate conveyor belt is transported at a speed of 0.2 m / min, and the other conditions and parameters are exactly the same as those in application example 1.

[0076] Comparative application example 1

[0077] The only difference between this application example and application example 1 is that after the PCB is pre-processed, a typesetting machine will adjust the position of the PCB so that one end of the PCB is clamped by the driven cathode fixture for conduction.

[0078] Performance Test:

[0079] The copper thickness of the electroplated board obtained from the corresponding use case and comparative application example is recorded every 1cm, and the range is calculated. The test results are shown in Table 1:

[0080] Table 1

[0081]

[0082]

[0083] It can be seen from Table 1 that from Application Examples 1-3, the extreme difference in copper thickness of the electroplated layer on the surface of the electroplated part obtained by using the PCB horizontal electroplating device of the present invention can reach within 3 μm.

[0084] By comparing Application Example 1 with Application Examples 4-5, it can be seen that in the method for horizontal electroplating of PCBs described in the present invention, the current density of electroplating will affect the electroplating effect. When the current density of electroplating is controlled within the range of 10ASF to 70ASF, the electroplating effect is better. If the current density of electroplating is too large, the current of the conductive ejector pin is too large, which may cause part of the coating to be destroyed, thereby increasing the thickness difference of the coating and reducing the uniformity. If the current density of electroplating is too small, the metal ions in the electroplating solution are insufficient to fully cover the surface of the electroplated part, resulting in local electroplating, which may cause the surface of the electroplated part to be rough, uneven and have quality problems.

[0085] By comparing Application Example 1 with Application Examples 6-7, it can be seen that in the method for horizontal electroplating of PCBs of the present invention, the conveying speed of the plate conveyor belt will affect the electroplating effect. The electroplating effect is better when the current density of the electroplating is controlled at 0.3m / min to 3.0m / min. If the conveying speed of the plate conveyor belt is too fast, the roller will slip, scratch the PCB surface, and even the heat between the material and the roller will be too much, causing deformation and protrusions on the material surface, affecting the surface quality. If the conveying speed of the plate conveyor belt is too slow, the contact point between the ejector pin and the board will appear, resulting in uneven coating, decreased uniformity, and even possible scorching or rough crystallization.

[0086] From the comparison between Application Example 1 and Comparative Application Example 1, it can be seen that the device for horizontal electroplating of PCBs described in the present invention eliminates the conductive clamp, and uses the roller itself to conduct electricity, thereby achieving large-area multi-point conductivity of the entire board, so that the current is evenly distributed. The conductive roller tightly presses the electroplated board to conduct electricity while transmitting it, which can not only perform electroplating production on hard boards, but also realize electroplating production on flexible boards.

[0087] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A device for horizontal electroplating of PCB, characterized in that: The device for horizontal electroplating of PCBs includes a plate-plating conveyor belt; At least one conductive roller is respectively arranged on both sides of the plated plate conveyor belt perpendicular to the direction of the plated plate conveyor belt, a conductive shaft core is passed through the central axis of the conductive roller, and the conductive shaft core is connected to a power source; The conductive roller is also provided with at least three movable conductive ejectors; the movable conductive ejectors are arranged along the conductive axis toward the circumferential surface of the conductive roller; The distribution of the at least three movable conductive pins ensures that when the conductive roller is rolling, at least one movable conductive pin on each side of the plate-plating conveyor belt connects the conductive shaft core and the plate-plating conveyor belt.

2. The device for horizontal electroplating of PCB as claimed in claim 1, characterized in that: The length of the movable conductive ejector pin is a, the distance from the conductive axis to the circumferential surface of the conductive roller is b, and a=b.

3. The device for horizontal electroplating of PCB as claimed in claim 1 or 2, characterized in that: The movable conductive ejector pin is connected to the conductive axis through a conductive elastic component; Preferably, the conductive elastic component comprises a conductive spring.

4. The device for horizontal electroplating of PCB according to any one of claims 1 to 3, characterized in that: The distance between two adjacent conductive rollers is 1 cm to 20 cm.

5. The device for horizontal electroplating of PCB according to any one of claims 1 to 4, characterized in that: Movable conductive ejector pins are arranged in 3 to 8 directions of the conductive roller.

6. The device for horizontal electroplating of PCB according to any one of claims 1 to 5, characterized in that: The number of movable conductive pins arranged in each direction of the conductive roller is 3 to 30.

7. The device for horizontal electroplating of PCB according to any one of claims 1 to 6, characterized in that: The device for horizontal electroplating of PCB also includes an insulating roller; Preferably, the insulating roller is arranged on the plated plate conveyor belt, on the opposite side of the conductive roller; Preferably, an insulating axis is arranged at the center of the insulating roller.

8. The device for horizontal electroplating of PCB according to any one of claims 1 to 7, characterized in that: The conductive axis is connected to the cathode of the power supply.

9. A method for horizontal electroplating of a PCB, characterized in that: The method uses the device for horizontal electroplating of PCB as claimed in any one of claims 1 to 8, and the method comprises the following steps: The plated plate is placed on the plated plate conveyor belt, and the conductive axis of each conductive roller is connected to the cathode of the power supply. When the power supply is turned on, the plated plate conveyor belt starts to transport for horizontal electroplating.

10. The method for horizontal electroplating of PCB as claimed in claim 9, characterized in that: The current density of the energization is 10ASF to 70ASF; Preferably, the conveying speed of the plate conveyor belt is 0.3m / min to 3.0m / min.

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