PCB conductive film production process and PCB conductive film production equipment

Abstract

The present invention provides a PCB conductive film generation process and a PCB conductive film generation device. The PCB conductive film generation process sequentially processes the following steps on the PCB: roughening of both sides, hole shaping, oxidation and catalysis. At least one of the hole shaping, oxidation and catalysis steps includes allowing the PCB to pass through a treatment tank containing a treatment liquid and then be sent out, the treatment tank includes a treatment area and an output area, and a liquid level control mechanism is arranged between the treatment area and the output area; the liquid level control mechanism includes a movable roller and a positioning roller; by translating the movable roller, the size of the channel can be adjusted by changing the gap between the movable roller and the positioning roller, and the flow rate of the treatment liquid above the positioning roller can be changed, so as to compensate for the flow rate change caused by the passage of the PCB below the positioning roller in real time, so as to control the liquid level in the treatment area between the first threshold value and the second threshold value, effectively avoiding the liquid level in the treatment area from being too low or too high, ensuring the treatment effect while avoiding waste and reducing production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB production, and in particular to a PCB conductive film production process and a PCB conductive film generating device. Background Art

[0002] PCB conductive film has the advantages of good conductivity and high temperature resistance and is widely used. In the process of PCB conductive film production, the PCB needs to be immersed in the treatment liquid to allow the PCB to fully react with the treatment liquid. Since the PCB remains in a moving state on the production line, the treatment liquid is also in a flowing state. After the PCB fully reacts with the treatment liquid in the treatment area, it enters the output area through a solid roller for arrangement.

[0003] Before the start of conductive film production, the total amount of treatment liquid required is determined based on the total surface area of ​​the PCB batch. The treatment liquid is continuously injected into the treatment area, and a solid roller is used to limit the flow of the treatment liquid to the output area. A treatment liquid with a certain depth is formed in the treatment area, so that the PCB can fully react with the treatment liquid before entering the output area.

[0004] Since multiple PCBs are processed simultaneously on the production line, the distances between two adjacent PCBs are different, and the shapes and sizes of the PCBs are different, so that the gap under the solid roller is constantly changing, and the flow rate of the treatment liquid from the bottom of the solid roller into the output area is constantly changing, so that the liquid level of the treatment liquid in the processing area is constantly changing. If the liquid level is too low, the reaction between the treatment liquid and the PCB surface is not sufficient, which seriously affects the product quality. The existing technology usually uses a higher treatment liquid injection speed to ensure the liquid level, but this method easily causes more treatment liquid to maintain a high liquid level, and a large amount of treatment liquid overflows from the top of the solid roller to the output area without reaction, resulting in low utilization of the treatment liquid, which is easy to cause waste and increase production costs. Summary of the invention

[0005] The present invention provides a PCB conductive film production process and a PCB conductive film production device, which can effectively control the liquid level, ensure product quality and reduce costs.

[0006] On the one hand, the present invention provides a PCB conductive film production process, which sequentially processes the PCB in the following steps:

[0007] a. Roughening on both sides;

[0008] b. Hole cleaning: ultrasonic penetration and wetting of the hole wall of the PCB to arrange the hole wall charge and improve oxidation adsorption;

[0009] c. oxidation to deposit the desired oxide layer on the PCB; and,

[0010] d. catalyzing to form a polymeric conductive layer on the oxide layer;

[0011] Wherein, in at least one of step b, step c and step d, the PCB is sent out after passing through a treatment tank containing a treatment liquid, the treatment tank includes a treatment area and an output area, the treatment liquid is injected into the treatment area and flows out from the output area; a liquid level control mechanism is provided between the treatment area and the output area; the PCB is sent out from the output area through the bottom of the liquid level control mechanism after being immersed in the treatment area;

[0012] The liquid level control mechanism comprises a movable roller and a positioning roller arranged along the PCB conveying direction; the positioning roller is positioned in the processing tank, the movable roller is arranged obliquely above the positioning roller, an adjustable channel for the processing liquid to flow from the processing area to the output area is formed between the movable roller and the positioning roller, and the movable roller is horizontally movable along the PCB conveying direction;

[0013] When the liquid level in the processing area is lower than a first threshold value, the first threshold value is higher than the top of the positioning roller, the movable roller translates close to the positioning roller to reduce the size of the adjustable channel and reduce the flow rate of the processing liquid in the adjustable channel, thereby increasing the liquid level in the processing area;

[0014] When the liquid level in the processing area is higher than a second threshold value, the second threshold value is equal to or lower than the top of the active roller, and the second threshold value is higher than the first threshold value, the active roller translates away from the positioning roller to increase the size of the adjustable channel, increase the flow rate of the processing liquid in the adjustable channel, and thus reduce the liquid level in the processing area.

[0015] The movable roller is closer to the processing area than the positioning roller, the top of the movable roller is higher than the top of the positioning roller, and the bottom of the movable roller is higher than the bottom of the positioning roller and lower than the top of the positioning roller.

[0016] The top of the movable roller is lower than the top opening of the processing tank. When the liquid level in the processing area is higher than the top of the movable roller, the processing liquid in the processing area flows from the top of the movable roller into the output area.

[0017] Wherein, the movable roller and the positioning roller are both cylindrical.

[0018] Wherein, the positioning roller is arranged to rotate around its own axis, and its bottom rotates toward the output area.

[0019] The movable roller is arranged to rotate around its own axis, and a plurality of water grooves are arranged on the surface of the movable roller. The plurality of water grooves are arranged around the movable roller. When the movable roller rotates so that the notch of the water groove is located at the top of the movable roller, the bottom of the water groove is biased toward one side of the positioning roller.

[0020] At least one end of the movable roller is connected to an automatic adjustment mechanism, which includes a reduction gear set, an output gear and a rack. The input end of the reduction gear set is connected to the movable roller, and the output end is connected to the output gear. The rotation directions of the movable roller and the output gear are opposite. The rack is arranged on the wall of the processing tank and meshes with the bottom of the output gear.

[0021] When the processing liquid flows from the top of the movable roller to the output area, the processing liquid enters the water tank and pushes the top of the movable roller to rotate toward the positioning roller. The movable roller drives the output gear to rotate on the output gear through the reduction gear set, so that the movable roller translates in the direction away from the positioning roller.

[0022] Wherein, a linear drive mechanism is arranged outside the processing tank, the linear drive mechanism is connected with a slider, and an abutment portion is arranged on the reduction gear group; when the liquid level in the processing area is lower than a first threshold value, the linear drive mechanism drives the slider to move toward the direction close to the positioning roller, and the slider abuts against the abutment portion to drive the movable roller to move toward the direction close to the positioning roller; when the movable roller moves to a preset position in the direction close to the positioning roller, the linear drive mechanism drives the slider to move toward the direction away from the positioning roller, and the slider is separated from the abutment portion.

[0023] Among them, the PCB is driven to move in the processing tank by a conveyor line, and the conveyor line is located below the liquid level control mechanism, which includes a conveying drive mechanism and a plurality of conveying rollers. The plurality of conveying rollers are arranged along the conveying direction of the PCB, and the conveying drive mechanism is transmission-connected to the conveying rollers to drive the conveying rollers to rotate around their own axes; the processing area is provided with a plurality of pressure rollers, and the pressure rollers are connected to the processing tank to rotate around their own axes, and the pressure rollers are located above the conveying rollers to limit the PCB between the pressure rollers and the conveying rollers.

[0024] Wherein, the positioning roller is flush with the bottom of the pressing roller, and the outer diameter of the positioning roller is smaller than the outer diameter of the pressing roller.

[0025] On the other hand, the present invention provides a PCB conductive film production device, which adopts the above-mentioned PCB conductive film production process, and includes a two-side roughening device, a pore-forming device, an oxidation device and a catalytic device arranged in sequence; at least one of the pore-forming device, the oxidation device and the catalytic device includes a treatment tank;

[0026] The treatment tank comprises a treatment area and an output area, the treatment liquid is injected into the treatment area and flows out from the output area; a liquid level control mechanism is arranged between the treatment area and the output area; the PCB is sent out from the output area through the bottom of the liquid level control mechanism after being immersed in the treatment area;

[0027] The liquid level control mechanism comprises a movable roller and a positioning roller arranged along the PCB conveying direction; the positioning roller is positioned in the processing tank, the movable roller is arranged obliquely above the positioning roller, an adjustable channel for the processing liquid to flow from the processing area to the output area is formed between the movable roller and the positioning roller, and the movable roller is horizontally movable along the PCB conveying direction;

[0028] When the liquid level in the processing area is lower than a first threshold value, the first threshold value is higher than the top of the positioning roller, the movable roller translates close to the positioning roller to reduce the size of the adjustable channel and reduce the flow rate of the processing liquid in the adjustable channel, thereby increasing the liquid level in the processing area;

[0029] When the liquid level in the processing area is higher than a second threshold value, the second threshold value is equal to or lower than the top of the active roller, and the second threshold value is higher than the first threshold value, the active roller translates away from the positioning roller to increase the size of the adjustable channel, increase the flow rate of the processing liquid in the adjustable channel, and thus reduce the liquid level in the processing area.

[0030] The invention provides a PCB conductive film production process and a PCB conductive film production device. The PCB is processed in at least one step of hole filling, oxidation and catalysis by using a processing tank containing a processing liquid. The processing liquid flowing from the processing area to the output area is mainly divided into two parts, which pass through the upper and lower sides of the positioning roller respectively. The positioning roller is relatively fixed. By horizontally moving the movable roller, the size of the channel can be adjusted by changing the gap between the movable roller and the positioning roller. The flow rate of the processing liquid above the positioning roller can be changed, thereby compensating for the flow change caused by the passage of the PCB under the positioning roller in real time. When the flow rate of the processing liquid through the adjustable channel increases, the processing liquid in the processing area can flow more into the output channel, thereby reducing the liquid level in the processing area. Conversely, the liquid level in the processing area can be increased to control the liquid level in the processing area between the first threshold value and the second threshold value, effectively avoiding the liquid level in the processing area from being too low or too high, ensuring the processing effect, avoiding waste, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. The drawings described below are only drawings corresponding to some embodiments of the present invention.

[0032] Figure 1 It is a structural schematic diagram of a PCB conductive film generating device provided in a preferred embodiment of the present invention;

[0033] Figure 2 It is a schematic diagram of the process of producing a PCB conductive film provided by a preferred embodiment of the present invention;

[0034] Figure 3 yes Figure 1 A schematic diagram of the structure of the hole-forming device of the PCB conductive film production equipment;

[0035] Figure 4 yes Figure 3 A partial cross-sectional view of the adjustable channel of the middle-hole device at the liquid level control mechanism when the size is smaller;

[0036] Figure 5 yes Figure 4 A partial cross-sectional view of the adjustable channel of the middle-hole device at the liquid level control mechanism when the size is larger;

[0037] Figure 6 yes Figure 3 A schematic diagram of the structure of the automatic adjustment mechanism of the center hole adjustment device;

[0038] Figure 7 yes Figure 6 Schematic diagram of the exploded view of the automatic adjustment mechanism. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0040] The terms "first", "second", etc. in the present invention are used for descriptive purposes only and should not be understood as indicating or implying relative importance, and should not be used as a limitation on the order of precedence.

[0041] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] The preferred embodiment of the present invention provides a PCB conductive film production process and a PCB conductive film production device. The conductive film production device uses the PCB conductive film production process to process the PCB. Figure 1 The conductive film production equipment includes a two-side roughening device 1, a first cleaning device 2, a hole-forming device 3, a second cleaning device 4, an oxidation device 5, a third cleaning device 6, a catalytic device 7, a fourth cleaning device 8, a board collecting machine 9 and a conveyor line 10 arranged in sequence. The structures of the hole-forming device 3, the oxidation device 5 and the catalytic device 7 can adopt the same structure, wherein the type of treatment liquid contained is selected according to the treatment steps. The conveyor line 10 is used to drive the PCB to move in each device in sequence to perform the treatment operation of each step.

[0043] See also Figure 2 The PCB conductive film generation process performs the following steps on the PCB in sequence.

[0044] Step S100, roughening both sides. The two-side roughening device 1 roughens both sides of the PCB to increase the surface roughness of the PCB, form a microscopic concave-convex structure, and mechanically interlock the conductive film with the PCB to improve the structural strength; at the same time, in the subsequent oxidation and catalytic process, it can ensure that the treatment liquid is fully in contact, improve the reaction efficiency, promote the uniform generation of the conductive film, reduce defects such as bubbles, prevent peeling caused by mechanical stress or thermal expansion, and improve product reliability.

[0045] Step S200 , first cleaning: The PCB is treated in this step by the first cleaning device 2 .

[0046] In this step, the PCB is sequentially subjected to overflow water washing and high-pressure water washing to remove debris formed during the roughening process on both sides, so that the surface of the PCB is clean to facilitate the subsequent oxidation reaction.

[0047] Step S300 is hole-smoothing, where ultrasonic waves penetrate and wet the hole walls of the PCB to adjust the hole wall charges and improve oxidation adsorption. The PCB is processed in this step by the hole-smoothing device 3 .

[0048] The pore-forming device 3 includes a treatment tank 30. This step includes sending the PCB out after passing through the treatment tank 30 containing the treatment liquid. The treatment liquid used for pore-forming is an alkaline solution with a pore-forming agent added thereto, with a pH value of 10-11 and a treatment temperature of 45-50 degrees. The alkaline liquid can be a sodium carbonate solution, and the pore-forming agent can be various pore-forming agents in the prior art.

[0049] In this embodiment, in order to improve the hole-forming effect, 1000KG of hole-forming agent contains: ethyleneamine X-012, 180-285KG, epoxyethylene epoxypropylene copolymer 0.2-0.5KG; imidazole derivative 0.3-0.8KG, salt 0.3-0.5KG, and the balance is DI water. Enamine chemical materials with special groups and properties are used to clean the PCB hole wall, change the electrical properties of the hole wall, and enhance the adsorption of metal on the hole wall in subsequent processes. The main body is enamine, and the others are auxiliary. The surfactant is used to reduce the surface tension of the liquid, the imidazole substance can effectively control the reaction rate, and the salt is used to absorb the reaction heat.

[0050] The production method of the pore-forming agent is to add the above-mentioned substances in a clean mixing tank in turn and stir until they are completely dissolved; after passing the inspection, filter and barrel.

[0051] like Figure 3 As shown, the hole-forming device 3 includes a processing tank 30, which includes a processing area 301 and an output area 302. The processing liquid is injected into the processing tank 30 at the processing area 301 and flows out from the output area 302; a liquid level control mechanism 31 is arranged between the processing area 301 and the output area 302, and the PCB is sent out from the output area 302 below the liquid level control mechanism 31 after being immersed in the processing area 301. The processing liquid in the processing area 301 maintains a relatively high liquid level so as to immerse the PCB so that the processing liquid and the PCB react fully; the processing liquid in the output area 302 maintains a relatively low liquid level so as to prevent the processing liquid from entering the next step with the PCB. The liquid level control mechanism 31 is used to control the water level of the processing area 301 to be higher than the output area 302, and the liquid level height of the processing area 301 can be controlled by adjusting the liquid level control mechanism 31.

[0052] like Figure 4 and Figure 5 As shown, the liquid level control mechanism 31 includes a movable roller 311 and a positioning roller 312 arranged along the PCB conveying direction, the positioning roller 312 is positioned in the processing tank 30, the movable roller 311 is arranged at an interval obliquely above the positioning roller 312, and an adjustable channel 310 for the processing liquid to flow from the processing area 301 to the output area 302 is formed between the movable roller 311 and the positioning roller 312. The movable roller 311 is horizontally movable along the PCB conveying direction, and the size of the adjustable channel 310 is controlled by translating the movable roller 311 to adjust the flow of the processing liquid in the adjustable channel 310, thereby adjusting the liquid level of the processing area 301.

[0053] When the liquid level in the processing area 301 is lower than a first threshold value, the first threshold value is higher than the top of the positioning roller 312, and the movable roller 311 translates close to the positioning roller 312 to reduce the size of the adjustable channel 310 and reduce the flow of the processing liquid in the adjustable channel 310, thereby increasing the liquid level in the processing area 301.

[0054] When the liquid level in the processing area 301 is higher than the second threshold value, the second threshold value is equal to or lower than the top of the active roller 311, and the active roller 311 translates away from the positioning roller 312 to increase the size of the adjustable channel 310 and increase the flow rate of the processing liquid in the adjustable channel 310, thereby lowering the liquid level in the processing area 301.

[0055] In this embodiment, the treatment liquid flowing from the treatment area 301 to the output area 302 is mainly divided into two parts, passing through the upper and lower sides of the positioning roller 312 respectively. The position of the positioning roller 312 is relatively fixed. By horizontally moving the movable roller 311 and changing the gap between the movable roller 311 and the positioning roller 312, the size of the channel 310 can be adjusted, and the flow of the treatment liquid above the positioning roller 312 can be changed, thereby compensating in real time for the flow change caused by the passage of the PCB below the positioning roller 312. When the flow of the treatment liquid through the adjustable channel 310 increases, the treatment liquid in the treatment area 301 can flow more into the output channel, thereby reducing the liquid level of the treatment area 301. Conversely, the liquid level of the treatment area 301 can be increased to control the liquid level of the treatment area 301 between the first threshold and the second threshold, effectively avoiding the liquid level of the treatment area 301 from being too low or too high, ensuring the treatment effect while avoiding waste and reducing production costs.

[0056] The adjustable channel 310 is located between the movable roller 311 and the positioning roller 312. Its height is lower than the height of the processing liquid in the processing area 301, so it is relatively close to the PCB. The processing liquid at this height has basically reacted with the PCB, and will not cause waste when discharged to the output area 302. The height difference between the adjustable channel 310 and the output area 302 is small, which can reduce splashing of liquid when it flows down, making it convenient for staff to perform various operations during the operation of the equipment.

[0057] The movable roller 311 is closer to the processing area 301 relative to the positioning roller 312, the top of the movable roller 311 is higher than the top of the positioning roller 312, the bottom of the movable roller 311 is higher than the bottom of the positioning roller 312 and lower than the top of the positioning roller 312, and the processing liquid needs to bypass the bottom of the movable roller 311 and the top of the positioning roller 312 to flow into the conveying area. The siphon phenomenon is used to make the processing liquid pass through the gap between the movable roller 311 and the positioning roller 312, and the processing liquid flows more smoothly.

[0058] The top of the movable roller 311 is lower than the top opening of the processing tank 30. When the liquid level in the processing area 301 is higher than the top of the movable roller 311, the processing liquid in the processing area 301 flows from the top of the movable roller 311 into the output area 302 to avoid overflowing out of the processing tank 30 and facilitate the liquid level control of the processing area 301. At the same time, the processing liquid in the processing area 301 flows from the top of the movable roller 311 into the output area 302 via the positioning roller 312 to avoid the liquid level in the processing area 301 being too high and overflowing out of the processing tank 30, and to avoid the processing liquid directly falling from the top of the movable roller 311 into the output area 302 and causing splashing.

[0059] The movable roller 311 and the positioning roller 312 are both cylindrical, so as to facilitate processing and preparation, and the gap between the two can be adjusted. The upper and lower surfaces of the channel 310 are arc-shaped, which is conducive to the smooth passage of the treatment liquid.

[0060] The positioning roller 312 is rotatably arranged around its own axis, and its bottom rotates toward the output area 302 to facilitate smooth transportation of the PCB from below the positioning roller 312 .

[0061] The surface of the movable roller 311 is provided with a plurality of water grooves 3110, and the plurality of water grooves 3110 are arranged around the movable roller 311. When the movable roller 311 rotates so that the notch of the water groove 3110 is located at the top of the movable roller 311, the bottom of the water groove 3110 deviates to one side of the positioning roller 312.

[0062] like Figure 3 , Figure 6 and Figure 7 As shown, at least one end of the movable roller 311 is connected to an automatic adjustment mechanism 32, and the automatic adjustment mechanism 32 includes a reduction gear set 321, an output gear 322 and a rack 323. The input end 3211 of the reduction gear set 321 is connected to the movable roller 311, and the output end is connected to the output gear 322. The rotation directions of the movable roller 311 and the output gear 322 are opposite; the rack 323 is arranged on the groove wall of the processing groove 30 and is engaged with the output gear 322.

[0063] In this embodiment, the second threshold value is the top height of the movable roller. When the liquid level in the processing area 301 is higher than the second threshold value, that is, higher than the movable roller 311, and the processing liquid flows from the top of the movable roller 311 to the output area 302, the processing liquid enters the water tank 3110 and pushes the top of the movable roller 311 to rotate toward the positioning roller 312. The movable roller 311 drives the two output gears 322 to rotate through the reduction gear set 321. The top of the output gear 322 rotates away from the positioning roller 312, so that the movable roller 311 translates away from the positioning roller 312, thereby increasing the gap between the movable roller 311 and the positioning roller 312, and increasing the flow rate of the processing liquid in the adjustable channel 310, so that the liquid level in the processing area 301 is lower than the top surface of the movable roller 311, and the processing liquid no longer passes through the top of the movable roller 311, and the movable roller 311 stops rotating and stops translating. This structure can make the movable roller 311 automatically move in the direction away from the positioning roller 312, and the reduction gear set 321 can be used to convert the faster rotation speed of the movable roller 311 into the slower rotation speed of the output gear 322, thereby slowing down the translation speed of the movable roller 311, ensuring the translation stability, and avoiding the sudden change of the liquid level. When the liquid level in the processing area 301 is reduced, the processing liquid no longer passes through the top surface of the movable roller 311, and the movable roller 311 stops rotating, so that when the liquid level in the processing area 301 is higher than the second threshold, the movable roller 311 automatically moves and reaches a balanced state.

[0064] When the liquid level in the processing area 301 is lower than the second threshold value, the processing liquid will not flow from the top of the active roller 311 to the output area 302, and the processing liquid can pass through the adjustable channel 310, that is, the processing liquid flows from the bottom of the active roller 311. The structural design of the water tank 3110 makes it possible to have resistance between the water tank 3110 and the processing liquid at this time, and the processing liquid will not drive the active roller 311 to move, so that the active roller 311 will not translate.

[0065] In this embodiment, the output end of the reduction gear set 321 is connected to two output gears 322, and the two output gears 322 are arranged at intervals along the PCB conveying direction, so as to ensure the stability of the connection with the rack 323. In other embodiments, the output end of the reduction gear set 321 may be provided with only one output gear 322, and a linear guide mechanism may be provided between the reduction gear set 321 and the processing tank 30 to ensure the stability of the translation of the movable roller 311, and the linear guide mechanism may be the cooperation of a guide rail and a slider.

[0066] A linear drive mechanism 324 is provided outside the processing tank 30, and a slider 325 is connected to the linear drive mechanism 324. An abutment portion 326 is provided outside the reduction gear set 321. When the liquid level of the processing area 301 is lower than the first threshold value, the linear drive mechanism 324 drives the slider 325 to move toward the direction close to the positioning roller 312, and the slider 325 abuts against the abutment portion 326 to drive the movable roller 311 to move toward the direction close to the positioning roller 312. When the movable roller 311 moves to the preset position in the direction close to the positioning roller 312, the linear drive mechanism 324 drives the slider 325 to move away from the positioning roller 312, and the slider 325 is separated from the abutment portion 326. The preset position is the position where the gap between the movable roller 311 and the positioning roller 312 is at the minimum value, and the minimum value can be determined as needed, and can be 1-10 mm, so as to avoid the movable roller 311 directly contacting the positioning roller 312, resulting in the movable roller 311 rotating under the drive of the positioning roller 312.

[0067] When no PCB passes under the positioning roller 312, the flow rate of the treatment liquid passing under the positioning roller 312 is at the maximum state. When the gap between the movable roller 311 and the positioning roller 312 is at the minimum value at the same time, the injection flow rate of the treatment liquid is greater than the outflow flow rate of the treatment liquid from the treatment area 301, which can make the liquid level of the treatment area 301 inevitably in an upward trend to ensure that the liquid level of the treatment area 301 can be increased when the size of the adjustable channel 310 is the smallest. Before the equipment starts to operate, the appropriate injection flow rate of the treatment liquid can be calculated based on the outflow flow rate of the treatment liquid from the treatment area 301 to the output area 302 when the gap between the movable roller 311 and the positioning roller 312 is at the minimum value at the same time, so that the liquid level of the treatment area 301 can be in a slowly rising state, so as to improve the utilization rate of the treatment liquid.

[0068] The linear drive mechanism 324 can drive the movable roller 311 to move toward the positioning roller 312. The processing area 301 can be provided with a liquid level detector, which is used to detect the first threshold value and is electrically connected to the linear drive mechanism 324 through the control module, so as to detect the liquid level of the processing area 301 in real time and timely control the movement of the movable roller 311. The liquid level detector can be a float or various types of liquid level sensors.

[0069] The linear drive mechanism 324 can be a mechanism that can realize linear drive, such as a cylinder, a linear motor, etc. In other embodiments, the linear drive mechanism 324 can also be directly used to drive the movable roller 311 to move in two directions to control the size of the adjustable channel 310 and simplify the structure. The liquid level detector can detect the first threshold and the second threshold at the same time.

[0070] In this embodiment, both ends of the movable roller 311 are connected with the automatic adjustment mechanism 32 and the linear drive mechanism 324, which can ensure the stability of the translation of the movable roller 311 when the axial dimension of the movable roller 311 is large. As another embodiment, the movable roller 311 can be provided with the automatic adjustment mechanism 32 and the linear drive mechanism 324 at only one end, and the other end is connected to the processing tank 30 through the linear guide mechanism.

[0071] The PCB is driven to move in the processing tank 30 by the conveyor line 10. The conveyor line 10 is located below the liquid level control mechanism 31 and includes a conveying drive mechanism 101, a separation roller 102 and a plurality of conveying rollers 103. The plurality of conveying rollers 103 are arranged along the conveying direction of the PCB. The conveying drive mechanism 101 is connected to the separation roller 102 and the conveying roller 103 by transmission to drive the separation roller 102 and the conveying roller 103 to rotate around their own axis, thereby driving the PCB to move. The separation roller 102 is cylindrical and is located directly below the liquid level control mechanism 31 to separate the processing liquid in the processing area 301 and the output area 302, slowing down the flow rate of the processing liquid from the processing area 301 to the conveying area, so that the processing liquid fully reacts with the PCB in the processing area 301.

[0072] The processing area 301 is provided with a plurality of rollers 104, which rotate around their own axes and are connected to the processing tank 30. The rollers 104 are located above the conveying rollers 103 to limit the PCB between the rollers 104 and the conveying rollers 103, thereby ensuring that the PCB is immersed in the processing liquid and prevented from floating. The positioning roller 312 is flush with the bottom of the rollers 104 to ensure the smooth transportation of the PCB. The outer diameter of the positioning roller 312 is smaller than the outer diameter of the rollers 104, so that the top of the positioning roller 312 is lower than the top of the rollers 104, so that the entrance height of the adjustable channel 310 is located at the middle and lower position of the rollers 104, so that the processing liquid entering the adjustable channel 310 is the liquid after the reaction with the PCB, thereby improving the utilization rate of the processing liquid.

[0073] The pressure roller 104 includes a rotating shaft and a roller sheet. There are multiple roller sheets, which are arranged at intervals along the axial direction of the conveying roller 103. The roller sheet includes a rolling ring and a connecting rod. The rolling ring is coaxially arranged with the conveying roller 103. There are multiple connecting rods, which are connected between the rolling ring and the conveying roller 103. The rolling sheet is used to press down the PCB and can also play a stirring role, so that the PCB and the processing liquid react fully. The structure of the conveying roller and the pressure roller can be the same, which will not be repeated here.

[0074] The top surface of the pressing roller 104 is lower than the first threshold value, so that the pressing roller 104 is always located below the surface of the processing liquid, thereby preventing excessive mixing of air from affecting the reaction between the PCB and the processing liquid.

[0075] Step S400 , second cleaning: The PCB is cleaned by the second cleaning device 4 .

[0076] In this step, the PCB is sequentially subjected to a first water jet immersion, a second water jet immersion, a first overflow water wash, a first city water wash and drying.

[0077] Step S500: oxidation to deposit a desired oxide layer on the PCB. The PCB is treated in this step by an oxidation device 5 .

[0078] In this step, the structure of the oxidation device 5 and the hole-forming device 3 can be the same, and the treatment tank 30 used is the same as the treatment tank 30 used in the hole-forming step S300, and its structure is not repeated here. The treatment liquid is an oxidizing solution, and specifically a boric acid solution can be used. The PCB is immersed in the boric acid solution in the treatment area 301 for oxidation operation, the temperature is 86-90°C, the pH value is 6-7, and the oxidant can be potassium permanganate.

[0079] After the PCB is immersed in the oxidation treatment in the treatment area 301 , it passes under the liquid level control mechanism 31 and is sent out from the output area 302 to the next step.

[0080] The same liquid level control method as that in step S300 is adopted, and the liquid level control mechanism 31 can be used to adjust the liquid level of the oxidizing solution in the processing area 301 to ensure that the liquid level of the oxidizing solution in the processing area 301 is maintained between the first threshold value and the second threshold value. The PCB surface can fully react with the oxidizing solution to ensure product quality, and reduce the unreacted oxidizing solution directly entering the output area 302, thereby improving the utilization rate of the oxidizing solution.

[0081] In order to ensure the oxidation effect, the oxidation solution needs to be analyzed. The specific analysis steps are as follows.

[0082] Step S501, transfer 5 ml of uncooled oxidation solution into a 100 ml volumetric flask, and dilute it with DI water to a scale of 100 ml.

[0083] Step S502, transfer 1 ml of the diluted solution in step S501 to a 100 ml volumetric flask, and dilute it with DI water to a scale of 100 ml.

[0084] Step S503, using DI water as a reference solution, measuring its absorbance at a wavelength of 526 nm, and recording the reading.

[0085] Calculation method: photometric value × 2 = ML / L. The diluted test solution should be measured as soon as possible. The concentration of the oxidant in the oxidizing solution can be determined through three steps: dilution, absorbance measurement and conversion.

[0086] Step S600, third cleaning: The PCB is cleaned for the third time by a third device.

[0087] In this step, the PCB is sequentially subjected to sewage flushing, a third water jet immersion, acid washing, a fourth water jet immersion, a fifth water jet immersion, a second city water washing and drying.

[0088] Step S700: catalysis to form a polymer conductive layer on the oxide layer. The PCB is treated in this step by a catalytic device 7.

[0089] In this step, the structure of the catalytic device 7 and the hole-forming device 3 can be the same, and the treatment tank 30 used is the same as the treatment tank 30 used in the hole-forming step S300. The treatment liquid is a catalytic solution, which is used for environmentally friendly through-hole catalytic treatment of microporous circuit boards. It is an acidic mixed aqueous solution, and the molecules selectively react on the hole wall to form a layer of organic conductive film. The treatment temperature is 16-22°C, preferably 18°C.

[0090] After the PCB is immersed in the catalytic treatment in the treatment area 301 , it passes under the liquid level control mechanism 31 and is sent out from the output area 302 to the next step.

[0091] The same liquid level control method as that in step S300 is adopted to control the entire hole. The liquid level of the catalytic solution in the processing area 301 can be adjusted by using the liquid level control mechanism 31 to ensure that the liquid level of the catalytic solution in the processing area 301 is maintained between the first threshold value and the second threshold value. The PCB surface can fully react with the catalytic solution to ensure product quality, and reduce the unreacted catalytic solution from directly entering the output area 302, thereby improving the utilization rate of the catalytic solution.

[0092] Step S800, fourth cleaning: The PCB is cleaned by a fourth device.

[0093] In this step, the PCB is sequentially subjected to a sixth water jet immersion, a seventh water jet immersion, a second overflow water wash, a third city water wash, drying, and a drying combination.

[0094] Step S900: collecting the PCBs. The PCBs with the conductive film are collected by a board collecting machine 9.

[0095] The invention provides a PCB conductive film production process and a PCB conductive film production device. The PCB is processed in at least one step of hole filling, oxidation and catalysis by using a processing tank containing a processing liquid. The processing liquid flowing from the processing area to the output area is mainly divided into two parts, which pass through the upper and lower sides of the positioning roller respectively. The positioning roller is relatively fixed. By horizontally moving the movable roller, the size of the channel can be adjusted by changing the gap between the movable roller and the positioning roller. The flow rate of the processing liquid above the positioning roller can be changed, thereby compensating for the flow change caused by the passage of the PCB under the positioning roller in real time. When the flow rate of the processing liquid through the adjustable channel increases, the processing liquid in the processing area can flow more into the output channel, thereby reducing the liquid level in the processing area. Conversely, the liquid level in the processing area can be increased to control the liquid level in the processing area between the first threshold value and the second threshold value, effectively avoiding the liquid level in the processing area from being too low or too high, ensuring the processing effect, avoiding waste, and reducing production costs.

[0096] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A PCB conductive film production process, characterized in that: Perform the following steps on the PCB in sequence: a. Roughening on both sides; b. Hole cleaning: ultrasonic penetration and wetting of the hole wall of the PCB to arrange the hole wall charge and improve oxidation adsorption; c. oxidation to deposit the desired oxide layer on the PCB; and, d. catalyzing to form a polymeric conductive layer on the oxide layer; Wherein, in at least one of step b, step c and step d, the PCB is sent out after passing through a treatment tank containing a treatment liquid, the treatment tank includes a treatment area and an output area, the treatment liquid is injected into the treatment area and flows out from the output area; a liquid level control mechanism is provided between the treatment area and the output area; the PCB is sent out from the output area through the bottom of the liquid level control mechanism after being immersed in the treatment area; The liquid level control mechanism comprises a movable roller and a positioning roller arranged along the PCB conveying direction; the positioning roller is positioned in the processing tank, the movable roller is arranged obliquely above the positioning roller, an adjustable channel for the processing liquid to flow from the processing area to the output area is formed between the movable roller and the positioning roller, and the movable roller is horizontally movable along the PCB conveying direction; When the liquid level in the processing area is lower than a first threshold value, the first threshold value is higher than the top of the positioning roller, the movable roller translates close to the positioning roller to reduce the size of the adjustable channel and reduce the flow rate of the processing liquid in the adjustable channel, thereby increasing the liquid level in the processing area; When the liquid level in the processing area is higher than a second threshold value, the second threshold value is equal to or lower than the top of the active roller, and the second threshold value is higher than the first threshold value, the active roller translates away from the positioning roller to increase the size of the adjustable channel, increase the flow rate of the processing liquid in the adjustable channel, and thus reduce the liquid level in the processing area.

2. The PCB conductive film production process according to claim 1, characterized in that: The movable roller is closer to the processing area than the positioning roller, the top of the movable roller is higher than the top of the positioning roller, and the bottom of the movable roller is higher than the bottom of the positioning roller and lower than the top of the positioning roller.

3. The PCB conductive film production process according to claim 2, characterized in that: The top of the movable roller is lower than the top opening of the processing tank. When the liquid level of the processing area is higher than the top of the movable roller, the processing liquid in the processing area flows from the top of the movable roller into the output area.

4. The PCB conductive film production process according to claim 3, characterized in that: The movable roller and the positioning roller are both cylindrical.

5. The PCB conductive film production process according to claim 4, characterized in that: The positioning roller is rotatably arranged around its own axis, and its bottom portion rotates toward the output area.

6. The PCB conductive film production process according to claim 4, characterized in that: The movable roller is arranged to rotate around its own axis, and a plurality of water grooves are arranged on the surface of the movable roller. The plurality of water grooves are arranged around the movable roller. When the movable roller rotates so that the notch of the water groove is located at the top of the movable roller, the bottom of the water groove is biased toward one side of the positioning roller; At least one end of the movable roller is connected to an automatic adjustment mechanism, which includes a reduction gear set, an output gear and a rack. The input end of the reduction gear set is connected to the movable roller, and the output end is connected to the output gear. The rotation directions of the movable roller and the output gear are opposite. The rack is arranged on the wall of the processing tank and meshes with the bottom of the output gear. When the processing liquid flows from the top of the movable roller to the output area, the processing liquid enters the water tank and pushes the top of the movable roller to rotate toward the positioning roller. The movable roller drives the output gear to rotate on the output gear through the reduction gear set, so that the movable roller translates in the direction away from the positioning roller.

7. The PCB conductive film production process according to claim 6, characterized in that: A linear drive mechanism is arranged outside the processing tank, the linear drive mechanism is connected with a slider, and an abutment portion is arranged on the reduction gear set; when the liquid level in the processing area is lower than a first threshold value, the linear drive mechanism drives the slider to move toward the direction approaching the positioning roller, and the slider abuts against the abutment portion to drive the movable roller to move toward the direction approaching the positioning roller; when the movable roller moves to a preset position toward the direction approaching the positioning roller, the linear drive mechanism drives the slider to move toward the direction away from the positioning roller, and the slider is separated from the abutment portion.

8. The PCB conductive film production process according to claim 1, characterized in that: The PCB is driven to move in the processing tank by a conveyor line, and the conveyor line is located below the liquid level control mechanism, and includes a conveying drive mechanism and a plurality of conveying rollers, wherein the plurality of conveying rollers are arranged along the conveying direction of the PCB, and the conveying drive mechanism is transmission-connected to the conveying rollers to drive the conveying rollers to rotate around their own axes; a plurality of pressure rollers are provided in the processing area, and the pressure rollers are rotationally connected to the processing tank around their own axes, and the pressure rollers are located above the conveying rollers to limit the PCB between the pressure rollers and the conveying rollers.

9. The PCB conductive film production process according to claim 8, characterized in that: The positioning roller is flush with the bottom of the pressing roller, and the outer diameter of the positioning roller is smaller than the outer diameter of the pressing roller.

10. A PCB conductive film production device, characterized in that: The PCB conductive film production process according to any one of claims 1 to 9 comprises a two-side roughening device, a pore-forming device, an oxidation device and a catalytic device arranged in sequence; at least one of the pore-forming device, the oxidation device and the catalytic device comprises a treatment tank; The treatment tank comprises a treatment area and an output area, the treatment liquid is injected into the treatment area and flows out of the output area; a liquid level control mechanism is arranged between the treatment area and the output area; After the PCB is immersed in the treatment area, it is sent out from the output area through the bottom of the liquid level control mechanism; The liquid level control mechanism comprises a movable roller and a positioning roller arranged along the PCB conveying direction; the positioning roller is positioned in the processing tank, the movable roller is arranged obliquely above the positioning roller, an adjustable channel for the processing liquid to flow from the processing area to the output area is formed between the movable roller and the positioning roller, and the movable roller is horizontally movable along the PCB conveying direction; When the liquid level in the processing area is lower than a first threshold value, the first threshold value is higher than the top of the positioning roller, the movable roller translates close to the positioning roller to reduce the size of the adjustable channel and reduce the flow rate of the processing liquid in the adjustable channel, thereby increasing the liquid level in the processing area; When the liquid level in the processing area is higher than a second threshold value, the second threshold value is equal to or lower than the top of the active roller, and the second threshold value is higher than the first threshold value, the active roller translates away from the positioning roller to increase the size of the adjustable channel, increase the flow rate of the processing liquid in the adjustable channel, and thus reduce the liquid level in the processing area.

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