Electrolytic current control method and system for etching liquid regeneration

Abstract

The invention discloses an electrolytic current control method and system for etching liquid regeneration, and relates to the technical field of etching liquid electrolytic control. The electrolytic current control method for etching liquid regeneration comprises the following steps: acquiring a detected oxidation-reduction potential value of the etching liquid obtained by detection; obtaining an electrolytic current control signal according to a difference value between the detected oxidation-reduction potential value and a target oxidation-reduction potential value; and controlling the electrolytic current value of the electrolytic bath according to the electrolytic current control signal. According to the embodiment of the invention, the electrolytic current is accurately controlled, and the stability of the performance of the etching liquid is maintained, so that the use of chemicals and the energy consumption in the electrolysis process are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of etching solution electrolysis control, and in particular to an etching solution regeneration electrolysis current control method and system. Background Art

[0002] Printed circuit boards (PCBs) are key basic components in electronic devices. They are composed of insulating substrates and conductive patterns. They are mainly used to carry and connect various electronic components, and are responsible for current transmission and information transfer. PCBs are widely used in consumer electronics, communication equipment, computers, automotive electronics, medical equipment, new energy and other fields, and are an indispensable part of modern electronic products. In the PCB manufacturing process, acidic etching solutions are widely used for etching copper foil. However, as the etching process progresses (Cu 2+ +Cu→2Cu + ), Cu in etching solution + The etching ability will decrease rapidly and eventually lead to the failure of the etching solution. + Reconverted to Cu 2+ To restore the performance of the etching solution. However, since the copper etching reaction is cyclical, oxidants and hydrochloric acid need to be added periodically. This not only increases the production cost, but also the addition of a large amount of chemical reagents will cause the volume of the etching solution to increase, eventually becoming a large amount of etching waste liquid.

[0003] Waste etching liquid is classified as HW22 hazardous waste, and PCB manufacturers are usually required to collect it and hand it over to professional environmental protection companies for treatment. This process faces the risk of leakage in the transportation of hazardous waste liquid, complex treatment process, high cost and waste of resources, and poses a potential threat to the ecological environment. The in-situ regeneration and recycling of PCB etching waste liquid based on electrochemical technology and simultaneous resource recovery effectively overcome the above problems, as described in patents such as CN118147645A, CN115948770A or CN118147644A. This technology can reduce the use of chemicals and reduce energy consumption, and has been widely used. In the existing electrolytic regeneration process, the control of electrolytic current is a key link, which directly affects the regeneration efficiency of the etching solution and the recovery quality of copper. However, the current current control method mainly relies on manual operation or simple switch control, lacks accuracy and real-time performance, and is difficult to fine-tune the electrolytic process. There are also safety hazards and cost issues. Summary of the invention

[0004] The present invention provides an electrolytic current control method and system for etching solution regeneration, which can maintain the stability of etching solution performance by accurately controlling the electrolytic current, thereby greatly reducing the use of chemicals and energy consumption in the electrolytic process.

[0005] According to one aspect of the present invention, there is provided an electrolytic current control method for etching solution regeneration, comprising:

[0006] Obtaining a detected oxidation-reduction potential value of the etching solution;

[0007] Obtaining an electrolysis current control signal according to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value;

[0008] The electrolysis current value of the electrolytic cell is controlled according to the electrolysis current control signal.

[0009] Optionally, before obtaining the detected oxidation-reduction potential value of the etching solution, the method further includes:

[0010] The target redox potential value is preset.

[0011] Optionally, after controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal, the method further comprises:

[0012] The chlorine gas or electrolyte generated by electrolysis in the electrolytic cell is recycled to the etching cell to achieve regeneration of the etching solution.

[0013] Optionally, obtaining an electrolysis current control signal according to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value comprises:

[0014] According to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value, the difference is processed by using a PID algorithm to obtain the electrolysis current control signal.

[0015] Optionally, before controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal, the method further comprises:

[0016] The detected electrolysis current value of the electrolytic cell is obtained.

[0017] Optionally, the electrolysis current control signal includes a first electrolysis current value, and the first electrolysis current value is used to control the electrolysis current value of the electrolytic cell.

[0018] Optionally, the electrolysis current control signal includes a first electrolysis current error value, and the first electrolysis current error value is used to control the electrolysis current value of the electrolytic cell together with the detected electrolysis current value.

[0019] Optionally, controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal comprises:

[0020] Determine whether a first difference between the first electrolysis current value and the detected electrolysis current value is greater than 0;

[0021] When the first difference is greater than 0, the electrolysis current value of the electrolytic cell is increased until the detected electrolysis current value is equal to the first electrolysis current value.

[0022] Optionally, controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal comprises:

[0023] Determine whether the first electrolysis current error value is greater than 0;

[0024] When the first electrolysis current error value is greater than 0, the electrolysis current value of the electrolytic cell is increased until the detected electrolysis current value is equal to a second electrolysis current value, wherein the second electrolysis current value is the sum of the first electrolysis current value and the first electrolysis current error value.

[0025] According to another aspect of the present invention, there is provided an electrolytic current control system for etching solution regeneration, comprising:

[0026] An electrolytic cell, used for electrolyzing the etching solution after etching the printed circuit board;

[0027] An oxidation-reduction potential sensor, used to detect the oxidation-reduction potential of the etching solution;

[0028] A PID controller, the PID controller is connected to the oxidation-reduction potential value sensor, and is used to obtain an electrolysis current control signal according to a difference between the detected oxidation-reduction potential value and a target oxidation-reduction potential value;

[0029] An electrolysis current controller is connected to the PID controller and the electrolytic cell respectively, and is used to control the electrolysis current of the electrolytic cell according to the electrolysis current control signal.

[0030] The electrolytic current control method and system for etching liquid regeneration provided by the embodiment of the present invention adjusts the electrolytic current value of the electrolytic cell used for etching waste liquid treatment by obtaining the detected oxidation-reduction potential value of the etching liquid and obtaining the error value between the detected oxidation-reduction potential value and the preset target oxidation-reduction potential value, thereby controlling the etching liquid to regenerate the chlorine gas generated by electrolysis and maintaining the oxidation-reduction potential value in the etching liquid stable in the preset optimal range. By accurately controlling the electrolytic current, the performance of the etching liquid is kept stable, thereby greatly reducing the use of chemicals and the energy consumption in the electrolysis process.

[0031] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 A flow chart of a first electrolytic current control method for etching solution regeneration provided by an embodiment of the present invention;

[0034] Figure 2 A flow chart of a second electrolytic current control method for etching solution regeneration provided by an embodiment of the present invention;

[0035] Figure 3 A flow chart of a third electrolytic current control method for etching solution regeneration provided by an embodiment of the present invention;

[0036] Figure 4 Schematic diagram of automatic control of electrolytic current and ORP changes under different etching intensities;

[0037] Figure 5 A schematic structural diagram of a first electrolytic current control system for etching solution regeneration provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] Figure 1The flowchart of the electrolytic current control method for regenerating the first etching solution provided by the embodiment of the present invention is shown in FIG. Figure 1 , control methods include:

[0041] S101, obtaining a detected oxidation-reduction potential value of the etching solution.

[0042] The oxidation-reduction potential (ORP) value reflects the chemical activity state in the etching solution and is one of the key control indicators for evaluating the performance of the etching solution. The ORP value can effectively indicate the balance of the oxidant and the reductant in the etching solution, thus providing basic data for subsequent control.

[0043] The etching tank is used to etch and form a printed circuit board. Etching liquid is set inside the etching tank. A lead-tin anti-corrosion layer is pre-plated on the copper foil part of the outer layer of the circuit board to be retained, and the copper foil in the remaining area is chemically etched away to form a circuit pattern. Etching will produce etching waste liquid, which has a high copper content. Therefore, the etching waste liquid needs to be treated to extract the copper for reuse.

[0044] As an example, by electrolyzing the etching waste liquid in an electrolytic cell, the copper element of the copper chloride in the waste liquid is recovered, and the chlorine generated by the electrolysis can be used for etching solution regeneration. Since the chlorine gas undergoes an oxidation-reduction reaction with the monovalent copper ions in the etching solution to generate divalent copper compounds, the redox potential value in the etching solution is increased, and the etching efficiency is also improved. The electrolysis efficiency of the etching waste liquid is controlled by the electrolysis current value, and the electrolysis efficiency is related to the generation efficiency of chlorine gas, that is, the electrolysis efficiency is related to the redox potential value, and the redox potential value is used to reflect the redox property in the solution. The higher the redox potential value, the stronger the oxidizing property, and the lower the redox potential value, the stronger the reducing property. In other embodiments, other substances besides chlorine gas can also be recovered, such as recovering the electrolyte and returning the electrolyte to the etching tank.

[0045] Exemplarily, the detected oxidation-reduction potential value is the oxidation-reduction potential value of the etching solution at the current moment, and the detected oxidation-reduction potential value can be obtained by an oxidation-reduction potential value sensor. By obtaining the detected oxidation-reduction potential value of the etching solution in the etching tank, the current etching situation in the etching tank can be obtained. According to the current etching situation, the amount of chlorine used for regenerating the etching solution is controlled to ensure the stability of the oxidation-reduction potential value in the etching solution, thereby ensuring the etching efficiency.

[0046] S102, obtaining an electrolysis current control signal according to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value.

[0047] Among them, the target redox potential value is a pre-set redox potential value to ensure the stability of the etching process, and the target redox potential value can be set according to actual needs. The electrolysis current control signal is a control signal for adjusting the electrolysis current value of the electrolytic cell. The redox potential value is detected to have a difference with the target redox potential value. According to the difference between the redox potential value detected and the target redox potential value, the electrolysis current control signal is obtained to adjust the electrolysis current value, thereby controlling the amount of chlorine used for regeneration of the etching solution to ensure the stability of the redox potential value in the etching solution.

[0048] Exemplarily, the current redox potential value of the etching solution is compared with the preset target redox potential value, the difference between the two is calculated, and the deviation information is obtained for subsequent control adjustment. According to the deviation of the redox potential value and its changing trend, an electrolysis current control signal of the etching waste liquid is generated by an appropriate control algorithm (such as PID, fuzzy logic, artificial intelligence, model predictive control, etc.). The electrolysis current control signal is dynamically adjusted according to the redox potential deviation information, and the current of the electrolytic cell is continuously regulated so that the redox potential value of the etching solution gradually approaches the target redox potential value and remains stable. The electrolysis current control signal generation frequency is equal to the current redox potential value update frequency. The current redox potential value is updated once, and the electrolysis current control signal can be calculated once.

[0049] S103, controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal.

[0050] Among them, the electrolytic cell is used to electrolyze the etching waste liquid, extract the copper in the etching waste liquid for recycling, and at the same time, the chlorine gas generated by electrolysis is used to regenerate the etching liquid, treat the chlorine gas, protect the environment and reduce the use of oxidants. According to the electrolysis current control signal, the electrolysis current value of the electrolytic cell is controlled, thereby controlling the amount of chlorine gas generated by electrolysis, thereby maintaining the stability of the redox potential value in the etching tank, ensuring that the detected redox potential value of the etching liquid is stable in the preset optimal range, and ensuring the stability and etching efficiency during the etching process.

[0051] An electrolytic current control method for etching liquid regeneration provided by an embodiment of the present invention adjusts the electrolytic current value of an electrolytic cell used for etching waste liquid treatment by obtaining a detected oxidation-reduction potential value of the etching liquid and obtaining an error value between the detected oxidation-reduction potential value and a preset target oxidation-reduction potential value, thereby controlling the etching liquid to regenerate the chlorine gas generated by electrolysis and maintaining the oxidation-reduction potential value in the etching liquid stable within a preset optimal range. By precisely controlling the electrolytic current, the performance of the etching liquid is kept stable, thereby greatly reducing the use of chemicals and the energy consumption during the electrolysis process.

[0052] By real-time monitoring of the redox potential (ORP) of the etching solution in the etching production line, combined with a variety of classical and intelligent control algorithms, applied alone or in combination, the dynamic adjustment of the electrolysis current value during the electrolysis process is achieved, thereby accurately regulating the anode chlorine gas yield during the electrolysis process or the electrolyte returning to the etching production line for etching solution regeneration, ensuring that the ORP value of the etching solution is stable and maintained within the optimal range. The control method includes at least one of PID control, fuzzy logic, neural network, artificial intelligence technology, and advanced control strategies such as model predictive control (MPC), adaptive control and robust control. The optimized control method and system can not only effectively maintain the long-term stability of the etching solution performance, but also significantly reduce the use of chemicals such as hydrochloric acid and oxidants, and reduce the overall energy consumption during the electrolysis process. Through the current feedback control mechanism, the embodiment of the present invention improves the automation and intelligence level of the electrolysis process, reduces the dependence on manual intervention, and improves the safety and production efficiency of the system.

[0053] In general, the present invention provides an efficient, energy-saving and intelligent etching solution regeneration and recycling solution, which optimizes the utilization of chemical resources and energy consumption management in the printed circuit board (PCB) production process. With the control system provided by the embodiment of the present invention, the regeneration and reuse process of the acid etching solution (i.e., electrolyte) is optimized, which not only improves the resource utilization efficiency and reduces the production cost, but also promotes the greening and sustainable development of the PCB manufacturing process.

[0054] Exemplarily, before step S101, it also includes: determining whether etching is in progress. If etching is in progress, obtaining the detected oxidation-reduction potential value of the etching solution. During the etching process, the ORP sensor signal of the etching solution is monitored in real time, and the ORP sensor signal is processed and analyzed to obtain the current oxidation-reduction potential value.

[0055] Exemplarily, the step of obtaining the detected oxidation-reduction potential value of the etching solution includes: obtaining multiple sampled oxidation-reduction potential values; obtaining the detected oxidation-reduction potential value according to the average value of the multiple sampled oxidation-reduction potential values. The ORP output and setting are generally integers, such as 525mV, but for feedback control, such data is not accurate enough. For example, from 520mV to 519mV, such a jump change causes a large change in output. The embodiment of the present invention adopts this averaging method to make the data smoother and improve the control accuracy.

[0056] Furthermore, according to the average value of the plurality of sampled detected oxidation-reduction potential values, before obtaining the detected oxidation-reduction potential value, the plurality of sampled detected oxidation-reduction potential values ​​may be filtered or large error data may be eliminated.

[0057] The real-time sampling frequency of the redox potential value should not be lower than the current redox potential value update frequency, which can be set to 0.01-1000 Hz, preferably 0.1-10 Hz. The average value of the multiple sampled redox potential values ​​is taken as the current redox potential value of the etching solution, preferably retaining 2 or more decimal places for subsequent data analysis and processing.

[0058] Exemplarily, the step of controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal includes: when the electrolysis current control signal is lower than the set lower limit electrolysis current control signal, adjusting the electrolysis current value of the electrolytic cell to the set lower limit electrolysis current value; when the electrolysis current control signal is higher than the set upper limit electrolysis current control signal, adjusting the electrolysis current value of the electrolytic cell to the set upper limit electrolysis current value. In an embodiment of the present invention, by accurately controlling the electrolysis current value of the electrolytic cell, the state of the redox active substance in the etching solution can be effectively adjusted, thereby maintaining the stability of the etching solution performance. In the interval or end state of the etching process, the current of the electrolytic cell is adjusted to the set lower limit electrolysis current value.

[0059] Through this closed-loop feedback control method, real-time response and precise control are ensured during the electrolytic regeneration and recycling of the etching solution, reducing the consumption of chemicals and energy during the etching process.

[0060] For example, in the related art, the etching machine is set at 510mV. When the ORP value of the etching line is lower than 510mV, an oxidant will be automatically added, which will quickly increase the ORP value. The extent of the increase depends on the amount added and the etching workload at that time.

[0061] Our target ORP value should be higher than the OPR setting value of the etcher (i.e. 510mV), for example, it should be set to be greater than or equal to 515mV, or set to be greater than or equal to 518mV. When the OPR value is lower than 515mV or 518mV, the electrolytic current value of the electrolytic cell will be automatically increased, and under normal circumstances, the ORP of the etching production line will increase accordingly. When it is higher than 515mV or 518mV, it is necessary to appropriately lower the electrolytic current value of the electrolytic cell or maintain a balance. As a result, the production line reduces or even avoids the addition of oxidants, reducing the use of hydrochloric acid oxidants.

[0062] On the other hand, if the target ORP value (i.e., the target redox potential value) is set too high, such as 530mV, a lot of electrical energy will be wasted to increase the ORP value. The higher the ORP value, the worse the chlorine absorption or the lower the efficiency of energy consumption. In one embodiment, after theoretical analysis and field experiments, the target redox potential value is set to be greater than or equal to 515mV and less than or equal to 520mV. It is within a range that is neither too high nor too low.

[0063] Exemplarily, the step of obtaining the electrolysis current control signal according to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value includes: obtaining each electrolysis current control signal according to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value of each production line. Based on each electrolysis current control signal calculated for each etching production line, the maximum value of multiple electrolysis current control signals is output for multiple production lines. In the case where N electrolysis production lines and M etching production lines (M, N ≥ 1) work together, the oxidation-reduction potential (ORP) signal of each etching production line will be monitored in real time, and the required electrolysis current signal will be calculated separately according to the status of each production line. Based on the current demand calculated by each etching production line, the system will output the required maximum current signal.

[0064] On this basis, there are many ways to distribute the electrolytic current: average dispersion method: evenly distribute the highest current signal to all N electrolytic production lines, so that each electrolytic production line bears an equal current value, thereby achieving a balanced operation effect; same increment method: under the premise of ensuring that the current increase of each electrolytic production line is the same, adjust the current distribution so that the sum of the currents of all electrolytic production lines is equal to the highest current signal. This method ensures the synchronous growth between the electrolytic production lines and takes into account the control of the overall current; proportional distribution: according to the production load of each electrolytic production line, the current is distributed according to a certain proportion. For example, if the load of an electrolytic production line is 1 / 2 of that of another production line, it will get twice the current distribution. This method ensures that the current distribution matches the actual load and ensures the efficiency of the high-load production line; dynamic adaptive distribution: by real-time monitoring of the chemical properties of the electrolyte (such as ORP, pH value, temperature, etc.) and electrolysis efficiency, the current distribution is automatically adjusted, and the optimal dynamic distribution is performed according to the operating status and changing needs of each electrolytic production line to ensure that each electrolytic production line works in the optimal state. Regardless of which method is used, it can ensure that the system optimizes current distribution, reduces energy consumption and improves process efficiency while meeting the etching process requirements.

[0065] Based on the above embodiments, the present invention provides an exemplary description of how to accurately control the detected electrolysis current value of the electrolytic cell according to the first electrolysis current value. Figure 2 The flowchart of the electrolytic current control method for regenerating the second etching solution provided by the embodiment of the present invention is shown in FIG. Figure 2 , control methods include:

[0066] S201, preset a target redox potential value.

[0067] Among them, the target redox potential value is a pre-set redox potential value to ensure the stability of the etching process. The preset target redox potential value provides a basis for subsequently controlling the electrolysis current value according to the difference between the target redox potential value and the detected redox potential value.

[0068] Exemplarily, the target redox potential value is usually set according to the process requirements, generally not lower than the oxidant addition control limit of the etching machine ORP control system, and generally 1 to 30 mV higher than the value, preferably 5 to 10 mV, to ensure that the etching solution works within the optimal range. In actual production, the oxidant addition control limit of the etching machine ORP control system is generally set to 400 to 600 mV, and most of them are set to within the range of 480 to 550 mV.

[0069] S202, obtaining the detected oxidation-reduction potential value of the etching solution.

[0070] S203, according to the difference between the detected redox potential value and the target redox potential value, a PID algorithm is used to process the difference to obtain an electrolysis current control signal.

[0071] Among them, the electrolysis current control signal includes a first electrolysis current value, and the first electrolysis current value is used to control the electrolysis current value of the electrolytic cell. The PID algorithm is a calculation method that combines the three links of proportion, integration and differentiation in process control for automatic control. PID is a proportional term (Proportion), and the proportional term is that the current error directly affects the control quantity; the integral term (Integration), the integral term is that the cumulative value of the error affects the control quantity, which is used to eliminate static errors; the differential term (Differentiation), the differential term is that the rate of change of the error affects the control quantity, which is used to predict the error trend and adjust in advance. The formula of the PID algorithm is:

[0072]

[0073] e(t)=ORP set -ORP t

[0074] Among them, U t is the first electrolysis current value, e(t) is the difference between the detected redox potential value and the target redox potential value, and is the error, that is, the difference between the expected value and the actual value. set is the target redox potential value, ORP t is the redox potential value at time t, K p is the proportional gain, K i is the integral gain, K d is the differential gain. By performing proportional, integral and differential processing on the difference and then superimposing the output, the required first electrolysis current value can be obtained. The electrolysis current control signal can be obtained through a PID controller, and the PID algorithm is used to quickly obtain the electrolysis current control signal, adjust the electrolysis current value of the electrolytic cell to the first electrolysis current value, and control the redox potential value of the etching solution to ensure the stable performance of the etching solution.

[0075] In practical applications, PID controllers need to be discretized, especially for digital control systems. One of the common discretization methods is to use numerical integration and differentiation, usually performed over a sampling time interval T. The goal of discrete PID is to calculate the control output U at each sampling time k k .

[0076] (1) Error e(k)

[0077] Assume that the sampling time is, e(k) represents the error at the kth sampling time, that is,

[0078] e(k)=ORP set -ORP k

[0079] ORP set To set the target value, ORP k is the actual value of ORP at time k

[0080] (2) Proportional term P k

[0081] The proportional term acts directly on the current error, that is,

[0082] P k =K p *e(k)

[0083] (3) Integral item

[0084] The integral term can be approximated by the accumulation of errors, that is,

[0085] I k =I k-1 +K i *T*e(k)

[0086] Among them, when the first calculation is k-1 is 0

[0087] (4) Differential term D k

[0088] The differential term is approximated by the rate of change of the error using the finite difference method:

[0089]

[0090] Among them, e(k-1) is 0 when it is calculated for the first time.

[0091] (5) PID discretization formula

[0092] Adding the proportional, integral, and differential terms, the formula for discrete PID is:

[0093]

[0094] The above is the calculation process of position PID. If incremental PID is used, the calculation method is:

[0095] ΔUk=Kp*(ek-ek-1)+Ki*T*ek+Kd*ek-2ek-1+ek-2T

[0096] U k =ΔU k +U k-1

[0097] Among them, ΔU k is the output control adjustment amount. When calculating for the first time, U k The electrolytic current value of the electrolytic cell is obtained, and e(k-1) and e(k-2) are 0.

[0098] Final output current I out The following function is further calculated:

[0099]

[0100] Among them, I minset The minimum current set for the system, generally 10 to 150A / m 2 (calculated based on the projected area of ​​the electrolytic anode), I maxset The maximum current set for the system is generally 400 to 800 A / m 2 (Calculated based on the projected area of ​​the electrolytic anode).

[0101] Before applying the PID algorithm, it is necessary to first perform PID parameter tuning. PID parameter tuning refers to adjusting the proportional (Kp), integral (Ki), and differential (Kd) parameters according to the needs of the specific control system to obtain the best control performance. The purpose of tuning the PID parameters is to achieve rapid response, minimum steady-state error, and moderate overshoot of the system. Common tuning methods include trial and error, critical proportion method, Ziegler-Nichols method, general adjustment method, software optimization method, and model method. In actual operation, software optimization method and model method are preferred. Software optimization method refers to using control system simulation software (such as MATLAB, Simulink, Excel) or industrial controller automatic tuning function to automatically optimize PID parameters according to set performance indicators (such as minimum steady-state error, minimum overshoot, minimum response time, etc.). It mainly includes simulation optimization, genetic algorithm, gradient descent method, etc. This method has adaptive adjustment function, but the effect in actual application is highly uncertain.

[0102] PID parameter tuning based on the model method: Based on the chemical reaction process and its reaction kinetics in the process, the dynamic change equations of each component of the etching solution are established to establish a system model.

[0103] Cu during etching + The concentration c(Cu + ) k Changes:

[0104] c(Cu + ) k =c(Cu + ) add -c(Cu + ) dec

[0105] Among them, c(Cu + ) add Depends on the etching intensity (g / L). Influencing factors include etching rate of etching solution, PCB etching area and thickness, PCB etching board speed, total amount of etching solution, etc., which are in dynamic change.

[0106] Regeneration by electrolysis to produce chlorine:

[0107]

[0108] Among them, c(Cu + ) Cl2 and c(Cu + ) air Cu regenerated with chlorine and air respectively + concentration.

[0109] Regeneration by anodic electrolysis:

[0110] c(Cu + ) dec =c(Cu + ) ano +c(Cu + ) air

[0111] Among them, c(Cu + ) ano Cu for electrolytic anode regeneration + concentration.

[0112] c(Cu + ) Cl2 Mainly depends on the amount of chlorine produced by electrolysis and the effect of chlorine dissolution and absorption

[0113]

[0114]

[0115] Among them, m Cl2 is the amount of chlorine produced (mol), I is the electrolysis current (A), η iis the current efficiency of chlorine production in the electrolysis process, N elec is the number of electrolytic cells, M Cu+ is the molar mass of Cu (g / mol), η Cl2 Chlorine oxidation of Cu + Reaction efficiency 1, V etch is the total amount of etching solution (L), V cir is the etching solution circulation flow rate for chlorine dissolution and absorption (m 3 / h), η Cu+ Chlorine oxidation of Cu + The reaction efficiency is 2.

[0116] c(Cu + ) ano It mainly depends on the electrolysis current, the amount of reducing substances added to the anolyte and the circulation flow rate of the etching solution. + ) air are affected by multiple factors, and it is difficult to estimate them accurately.

[0117] Based on the above model, the transfer function of electrolysis current and ORP is obtained through iterative calculation, and the general adjustment method is further used to adjust the PID parameters, so that the system can quickly adjust the current to keep the ORP of the etching solution stable.

[0118] S204, obtaining the detected electrolysis current value of the electrolytic cell.

[0119] Among them, the detected electrolysis current value is the current electrolysis current value of the electrolytic cell, the detected electrolysis current value is obtained, and the current electrolysis current value of the electrolytic cell is adjusted according to the difference between the detected electrolysis current value and the first electrolysis current value, providing a basis for controlling the redox potential value of the etching solution.

[0120] S205, determining whether a first difference between the first electrolysis current value and the detected electrolysis current value is greater than 0.

[0121] Among them, the first electrolysis current value is the target electrolysis current value that needs to be adjusted to maintain the etching solution detection redox potential value. The detected electrolysis current value is the current electrolysis current value of the electrolytic cell. When the first difference is not equal to 0, the electrolysis current value of the electrolytic cell needs to be adjusted.

[0122] When the first difference is greater than 0, S206 is executed; when the first difference is less than 0, S207 is executed.

[0123] S206. When the first difference is greater than 0, the electrolysis current value of the electrolytic cell is increased until the detected electrolysis current value is equal to the first electrolysis current value.

[0124] Among them, when the first difference is greater than 0, the first electrolysis current value is greater than the detection electrolysis current value, the current electrolysis current value of the electrolytic cell is too small, and the electrolysis current value needs to be increased to increase the generation of chlorine, so that more chlorine is used for the regeneration of the etching solution, until the detection electrolysis current value is equal to the first electrolysis current value, ensuring that the redox potential value in the etching solution is stable in a preset optimal range. When the first difference is equal to 0, the first electrolysis current value is equal to the detection electrolysis current value, and there is no need to adjust the current electrolysis current value of the electrolytic cell, so as to maintain the redox potential value in the etching solution stable and ensure etching efficiency.

[0125] S207. When the first difference is less than 0, the electrolysis current value of the electrolytic cell is reduced until the detected electrolysis current value is equal to the first electrolysis current value.

[0126] Among them, when the first difference is less than 0, the first electrolysis current value is less than the detected electrolysis current value, the current electrolysis current value of the electrolytic cell is too large, and the electrolysis current value needs to be reduced to reduce the generation of chlorine, so that less chlorine is used for regeneration of the etching solution until the detected electrolysis current value is equal to the first electrolysis current value, ensuring that the redox potential value in the etching solution is stable in a preset optimal range.

[0127] S208, the chlorine gas or electrolyte generated by electrolysis in the electrolytic cell is recycled to the etching tank to achieve regeneration of the etching solution.

[0128] The chlorine gas undergoes an oxidation-reduction reaction with the monovalent copper ions in the etching solution to generate divalent copper compounds, thereby increasing the oxidation-reduction potential value in the etching solution, treating the chlorine gas and improving the etching efficiency.

[0129] Etching solution regeneration methods include:

[0130] 1) The etching waste liquid is electrolyzed through a diaphragm (common diaphragms such as polyester, polypropylene, etc., ceramic diaphragms and other diaphragms with certain isolation capabilities and acid-resistant and corrosion-resistant materials) electrolytic cell, wherein the chlorine gas produced by the anode is recycled to the etching line to achieve the regeneration of the etching liquid, wherein the chlorine gas recycling mainly includes mixed dissolution reaction methods such as jet suction based on a chlorine absorption cylinder or chlorine absorption tower showering. Among them, the etching waste liquid is the part of the etching liquid in the etching production line that overflows and is discharged after working for a period of time. The main reaction equation is as follows:

[0131] Electrolysis anode: 2Cl - -e - →Cl2↑,Cu + -e - →Cu 2+

[0132] Electrolytic cathode: Cu 2+ +e - →Cu + , Cu2+ +2e - →Cu,Cu + +e - →Cu

[0133] Etching solution regeneration: 2Cu + +Cl2→2Cu 2+ +2Cl - , 2Cu + +2HCl+1 / 2O2→2Cu 2+ +2Cl - +H2O;

[0134] 2) Use an ion membrane (ion exchange membrane) electrolyzer to directly regenerate and reuse the etching solution. The etching solution is passed into the anode of the ion membrane electrolyzer for direct regeneration, and then returns to the production line for etching. The main reaction equation is as follows:

[0135] Electrolytic anode and etching solution regeneration: Cu + -e - →Cu 2+ , 2Cu + +2HCl+1 / 2O2→2Cu 2+ +2Cl - +H2O

[0136] Electrolytic cathode: Cu 2+ +e - →Cu + , Cu 2+ +2e - →Cu,Cu + +e - →Cu

[0137] If necessary, a certain amount of reducing agent (such as FeCl2 (Fe 2+ : Generally maintain 1 ~ 50g / L, preferably 25 ~ 35g / L), NH4Cl (generally maintain 2 ~ 15g / L, preferably 5 ~ 8g / L)).

[0138] 3) Based on 2), the etching solution is indirectly regenerated and reused through the anolyte of the ion membrane (ion exchange membrane) electrolytic cell. Compared with the direct regeneration and reuse method in the above scheme, the indirect regeneration and reuse method refers to adding a buffer storage tank between the electrolytic cell and the etching work line, and a certain amount of reducing agent (such as FeCl2 (Fe 2+ : generally maintained at 1-50 g / L, preferably 25-35 g / L), NH4Cl (generally maintained at 2-15 g / L, preferably 5-8 g / L). The main reaction equation is as follows:

[0139] Electrolytic anode and etching solution regeneration: Cu + -e - →Cu 2+ , 2Cu + +2HCl+1 / 2O2→2Cu 2+ +2Cl - +H2O

[0140] Adding FeCl2 also includes: Fe 2+ -e - →Fe 3+

[0141] Add NH4Cl, then also include: 8Cl - +2NH4 + -6e - →N2↑+8HCl,

[0142] Electrolytic cathode: Cu 2+ +e - →Cu + , Cu 2+ +2e - →Cu,Cu + +e - →Cu

[0143] The electrolytic current control method for etching solution regeneration provided by the embodiment of the present invention adopts a PID algorithm to obtain a first electrolytic current value that needs to be adjusted, and through a first difference between the first electrolytic current value and the detected electrolytic current value, when the first difference is greater than 0, the electrolytic current value of the electrolytic cell is controlled to increase until the detected electrolytic current value is equal to the first electrolytic current value, thereby increasing the generation of chlorine gas and allowing more chlorine gas to be used for the regeneration of the etching solution; when the first difference is less than 0, the electrolytic current value of the electrolytic cell is controlled to decrease until the detected electrolytic current value is equal to the first electrolytic current value, thereby reducing the generation of chlorine gas and allowing less chlorine gas to be used for the regeneration of the etching solution; when the first difference is equal to 0, there is no need to adjust the electrolytic current value of the electrolytic cell, and the chlorine gas generated by electrolysis in the electrolytic cell is recycled to the etching cell to achieve the regeneration of the etching solution. The electrolytic current control signal is quickly obtained through the PID algorithm, and the electrolytic current value of the electrolytic cell is automatically controlled, thereby ensuring that the redox potential value of the etching solution is stable in a preset optimal range, reducing costs, ensuring etching efficiency, and improving production safety.

[0144] On the basis of the above-mentioned embodiment, the embodiment of the present invention provides an exemplary description of how to further accurately control the detected electrolysis current value of the electrolytic cell according to the first electrolysis current error value. Figure 3 The flowchart of the electrolytic current control method for regenerating the third etching solution provided in the embodiment of the present invention is shown in FIG. Figure 3 , control methods include:

[0145] S301, preset a target redox potential value.

[0146] S302, obtaining the detected oxidation-reduction potential value of the etching solution.

[0147] As an example, an ORP online monitoring device is installed in the etching line to monitor the ORP signal of the etching solution in real time, using the current signal transmission method. The ORP real-time sampling frequency is 20Hz, and the current ORP update frequency of the system is 0.5Hz.

[0148] S303, according to the difference between the detected redox potential value and the target redox potential value, the difference is processed by using a PID algorithm to obtain an electrolysis current control signal.

[0149] As an example, the current ORP value of the etching solution is compared with the preset target ORP value, the difference between the two is calculated, and the deviation information is obtained for subsequent control adjustment. According to the deviation of the ORP value and its changing trend, the PID control algorithm generates the electrolysis current control signal of the etching waste liquid. The control signal is dynamically adjusted according to the ORP deviation information, and the current of the electrolytic cell is continuously regulated so that the ORP value of the etching solution gradually approaches the target value and remains stable. The control signal generation frequency is consistent with the current ORP value update frequency, which is 0.5Hz.

[0150] According to the error between the current ORP value and the target ORP value, the electrolysis current control signal process is generated based on the PID control algorithm:

[0151] Use numerical integration and differentiation, usually performed over a sampling time interval T. The goal of discrete PID is to calculate the control output U at each sampling time instant k k .

[0152] (1) Error e(k)

[0153] Assume the sampling time is T, set to 2s, e(k) represents the error at the kth sampling time, that is,

[0154] e(k)=ORP set -ORP k

[0155] Among them, ORP set To set the target value, set it to 525mV, ORP k Update the current ORP value at time k.

[0156] (2) Proportional term P k

[0157] The proportional term acts directly on the current error, that is,

[0158] P k=K p *e(k)

[0159] (3) Integral term I k

[0160] The integral term can be approximated by the accumulation of errors, that is,

[0161] I k =I k-1 +K i *T*e(k)

[0162] Among them, when the first calculation is k-1 is 0.

[0163] (4) Differential term D k

[0164] The differential term is approximated by the rate of change of the error using the finite difference method:

[0165]

[0166] Among them, e(k-1) is 0 during the first calculation.

[0167] (5) PID discretization formula

[0168] Adding the proportional, integral, and differential terms, the formula for discrete PID is:

[0169]

[0170] The above is the calculation process of position PID. If incremental PID is used, the calculation method is:

[0171]

[0172] U k =ΔU k +U k-1

[0173] Among them, ΔU k is the output control adjustment amount. When calculating for the first time, U k The electrolytic current value of the electrolytic cell is obtained, and e(k-1) and e(k-2) are 0.

[0174] Final output current I out The following function is further calculated:

[0175]

[0176] Among them, I minset The minimum current set for the system is set to 100A / m 2 (calculated based on the projected area of ​​the electrolytic anode), Imaxset The maximum current set for the system, generally 400A / m 2 (Calculated based on the projected area of ​​the electrolytic anode).

[0177] Before applying the PID algorithm, you need to first perform PID parameter tuning. PID parameter tuning refers to adjusting the proportional (Kp), integral (Ki), and differential (Kd) parameters according to the needs of the specific control system to obtain the best control performance. The purpose of PID parameter tuning is to achieve fast system response, minimum steady-state error, and moderate overshoot.

[0178] PID parameter tuning based on the model method: Based on the chemical reaction process and its reaction kinetics in the process, the dynamic change equations of each component of the etching solution are established to establish a system model.

[0179] Cu during etching + The concentration c(Cu + ) k Changes:

[0180] c(Cu + ) k =c(Cu + ) add -c(Cu + ) dec

[0181] Among them, c(Cu + ) add It depends on the etching intensity (g / L). The influencing factors include etching rate of etching solution, PCB etching area and thickness, PCB etching board speed 4m / min, etching line length 4.8m, total amount of etching solution 2400L, etc., which are in dynamic change.

[0182] Cu during etching + Empirical relationship model between concentration and ORP:

[0183] ORP k =527.15-27.845*ln c(Cu + ) k

[0184] Regeneration by electrolysis to produce chlorine:

[0185] c(Cu + ) dec =c(Cu + ) Cl2 +c(Cu + ) air

[0186] Among them, c(Cu + ) Cl2and c(Cu + ) air Cu regenerated with chlorine and air respectively + concentration.

[0187] c(Cu + ) Cl2 Mainly depends on the amount of chlorine produced by electrolysis and the effect of chlorine dissolution and absorption

[0188]

[0189]

[0190] η i =0.2575*ln I-1.298

[0191] Among them, m Cl2 is the amount of chlorine produced (mol), I is the electrolysis current (A), the minimum current set by the system is 600A, and the current density is 100A / m 2 (calculated based on the projected area of ​​the electrolytic anode), the system is set to have a maximum current of 2400A and a current density of 400A / m 2 (calculated based on the projected area of ​​the electrolytic anode), η i is the current efficiency of chlorine production in the electrolysis process, calculated based on the empirical model, N elec is the number of electrolytic cells, which is 16, M Cu+ is the molar mass of Cu, which is 64 g / mol, η Cl2 Chlorine oxidation of Cu + The reaction efficiency is 1, the value is 0.85, V etch is the total amount of etching solution (2400L), V cir The circulation flow rate of etching solution used for chlorine dissolution and absorption is 20m 3 / h,η Cu+ Chlorine oxidation of Cu + The reaction efficiency is 2, and the value is 0.90.

[0192] Based on the above model, the transfer function between electrolysis current and ORP is obtained through iterative calculation, and the general adjustment method is further used to adjust the PID parameters, K p Is the proportional gain: 1200, K i is the integral gain: 10, K d The differential gain is 100, which allows the system to quickly adjust the current to maintain a stable ORP of the etching solution.

[0193] S304, obtaining the detected electrolysis current value of the electrolytic cell.

[0194] S305, determining whether the first electrolysis current error value is greater than 0.

[0195] Among them, the first electrolysis current error value is the difference between the target electrolysis current value and the current detected electrolysis current value. When the first electrolysis current error value is not equal to 0, the electrolysis current value of the electrolytic cell needs to be adjusted.

[0196] When the first electrolysis current error value is greater than 0, S306 is executed; when the first electrolysis current error value is less than 0, S307 is executed.

[0197] S306. When the first electrolysis current error value is greater than 0, the electrolysis current value of the electrolytic cell is increased until the detected electrolysis current value is equal to the second electrolysis current value.

[0198] Wherein, the second electrolysis current value is the sum of the first electrolysis current value and the first electrolysis current error value. When the first electrolysis current error value is greater than 0, the current electrolysis current value of the electrolytic cell is too small, and the electrolysis current value needs to be increased. The sum of the first electrolysis current error value and the detection electrolysis current value is the second electrolysis current value required by the electrolytic cell, which increases the generation of chlorine, so that more chlorine is used for the regeneration of the etching solution, and the redox potential value in the etching solution is guaranteed to be stable. When the first electrolysis current error value is equal to 0, the detection electrolysis current value is the electrolysis current value required by the electrolytic cell, and the current electrolysis current value of the electrolytic cell does not need to be adjusted, so that the redox potential value in the etching solution can be maintained stable, and etching efficiency is guaranteed.

[0199] S307. When the first electrolysis current error value is less than 0, the electrolysis current value of the electrolytic cell is reduced until the detected electrolysis current value is equal to the second electrolysis current value.

[0200] Wherein, the second electrolysis current value is the first electrolysis current value minus the first electrolysis current error value. When the first electrolysis current error value is less than 0, the current electrolysis current value of the electrolytic cell is too large, and the electrolysis current value needs to be reduced, and the difference between the electrolysis current value minus the first electrolysis current error value is the second electrolysis current value needed by the electrolytic cell, reducing the generation of chlorine, making less chlorine for the regeneration of etching solution, and ensuring that the redox potential value in the etching solution is stable.

[0201] Exemplarily, according to the generated electrolysis current control signal, the current value of the electrolytic cell is automatically adjusted. The frequency control signal generation frequency is adjusted to remain consistent, 0.5Hz. The adjustment range does not exceed the set minimum and maximum currents, which are 600A and 2400A respectively. By accurately controlling the electrolysis current, the state of the redox active substances in the etching solution can be effectively adjusted, thereby maintaining the stability of the etching solution performance. In the interval or end state of the etching process, the electrolytic cell current is adjusted to the set lower limit current.

[0202] S308, the chlorine gas or electrolyte generated by electrolysis in the electrolytic cell is recycled to the etching tank to achieve regeneration of the etching solution.

[0203] The chlorine gas undergoes an oxidation-reduction reaction with the monovalent copper ions in the etching solution to generate divalent copper compounds, thereby increasing the oxidation-reduction potential value in the etching solution, treating the chlorine gas and improving the etching efficiency.

[0204] The embodiment of the present invention provides a method for obtaining a first electrolysis current error value that needs to be adjusted by using a PID algorithm. When the first electrolysis current error value is greater than 0, the electrolysis current value of the electrolytic cell is controlled to increase to a second electrolysis current value, where the second electrolysis current value is the sum of the first electrolysis current error value and the detected electrolysis current value, thereby increasing the generation of chlorine gas and allowing more chlorine gas to be used for the regeneration of the etching solution. When the first electrolysis current error value is less than 0, the electrolysis current value of the electrolytic cell is controlled to decrease to a second electrolysis current value, where the second electrolysis current value is the detected electrolysis current value minus the first electrolysis current error value, thereby reducing the generation of chlorine gas and allowing less chlorine gas to be used for the regeneration of the etching solution. When the first electrolysis current error value is equal to 0, there is no need to adjust the electrolysis current value of the electrolytic cell. The electrolysis current control signal is quickly obtained through the PID algorithm, and the electrolysis current value of the electrolytic cell is automatically controlled, thereby ensuring the stability of the redox potential value of the etching solution, reducing costs, ensuring etching efficiency, and improving production safety. The automatic control of the electrolysis current and the change in ORP under different etching intensities are shown in the figure. Figure 4 shown.

[0205] Based on the same inventive concept, the present invention also provides an electrolytic current control system for etching solution regeneration. Figure 5 The schematic diagram of the structure of the electrolytic current control system for the first etching solution regeneration provided by the embodiment of the present invention is shown in FIG. Figure 5 The control system includes an etching tank 10, an electrolytic tank 20, a redox potential value sensor 30, a PID controller 40 and an electrolytic current controller 50. Among them, an etching liquid is set inside the etching tank 10 for etching a printed circuit board; the electrolytic tank 20 is connected to the etching tank 10, and is used to electrolyze the etching waste liquid generated by etching the printed circuit board; the redox potential value sensor 30 is connected to the etching tank 10, and is used to detect the redox potential value of the etching liquid in the etching tank 10; the PID controller 40 is connected to the redox potential value sensor 30, and is used to obtain an electrolytic current control signal according to the error value between the detected redox potential value and the target redox potential value; the electrolytic current controller 50 is respectively connected to the PID controller 40 and the electrolytic tank 20, and is used to control the electrolytic current value of the electrolytic tank 20 according to the electrolytic current control signal.

[0206] Exemplarily, the etching solution in the etching tank 10 is used to etch a printed circuit board, and the etching waste liquid generated during the etching process flows into the electrolytic tank 20, and the electrolytic tank 20 electrolyzes the etching waste liquid to extract copper, and the chlorine generated by the electrolysis is used to regenerate the etching solution. The oxidation-reduction potential value sensor 30 obtains the detected oxidation-reduction potential value of the etching solution in real time, and the PID controller 40 obtains the electrolysis current control signal according to the error value between the detected oxidation-reduction potential value and the preset target oxidation-reduction potential value. The electrolysis current controller 50 controls the electrolysis current value in the electrolytic tank 20 with the electrolysis current control signal, thereby controlling the amount of chlorine electrolyzed by the electrolytic tank 20, and controlling the oxidation-reduction potential value of the etching solution to ensure the stability of the etching solution.

[0207] Exemplarily, the electrolytic current control system for etching solution regeneration also includes a control module, which is mainly composed of a controller and its built-in program. The controller generally includes but is not limited to a combination of one or more of a PLC, a single-chip microcomputer, an industrial computer, a signal acquisition and control system, and an electronic computer. The control module has a built-in calculation and control program, stores relevant setting parameters, and performs signal collection, analysis and processing. The control module is connected to the ORP sensing module (i.e., the redox potential value sensor 30) to receive the etching solution ORP signal. Based on the built-in calculation and control program of the control module, ORP signal analysis and processing are performed, and an electrolytic current control signal is generated. The control module is connected to the electrolytic current control module to output the electrolytic current control signal.

[0208] Exemplarily, the core components of the electrolysis current controller 50 include current conversion and control equipment, such as a rectifier, and the electrolysis current controller 50 is used to receive an electrolysis current control signal.

[0209] For example, the electrolytic cell is generally divided into anode and cathode chambers by a common diaphragm or ion membrane, and is used for electrolytic treatment of etching solution or etching waste liquid after etching PCB. The chlorine gas or electrolytic anode liquid generated by the anode during the electrolysis process is returned to the etching production line to maintain the stability of the ORP of the etching solution.

[0210] Exemplarily, the control module also includes a human-machine interface and an interaction module, which can perform relevant parameter settings and operations.

[0211] An electrolytic current control system for etching solution regeneration provided by an embodiment of the present invention monitors the redox potential (ORP) of the etching solution of the etching work production line in real time. The system combines a variety of classical and intelligent control algorithms, which are applied alone or in combination to achieve dynamic adjustment of the current output during the electrolysis process, thereby accurately regulating the anode chlorine yield during the electrolysis process or the return of the electrolytic anode liquid to the etching production line for etching solution regeneration, ensuring that the etching solution ORP is stable and maintained within the optimal range. The control method includes PID control, fuzzy logic, neural network, artificial intelligence technology, and advanced control strategies such as model predictive control (MPC), adaptive control and robust control. The optimized control method and system can not only effectively maintain the long-term stability of the etching solution performance, but also significantly reduce the use of chemicals such as hydrochloric acid and oxidants, and reduce the overall energy consumption during the electrolysis process. Through the advanced current feedback control mechanism, the present invention greatly improves the automation and intelligence level of the electrolysis process, reduces the dependence on manual intervention, and improves the safety and production efficiency of the system.

[0212] Optionally, the electrolytic current control system for etching solution regeneration further includes a dissolving absorption cylinder 60, which is connected to the etching tank 10 and the electrolytic tank 20 respectively, receives the chlorine gas generated by the electrolytic tank, and regenerates the etching solution. The chlorine gas generated by electrolysis in the electrolytic tank 20 is injected into the dissolving absorption cylinder 60, and the etching solution is oxidized in the dissolving absorption cylinder 60, and the etching solution is regenerated and then flows into the etching tank 10.

[0213] It is understandable that, in other implementations, chlorine gas or electrolyte may be directly injected into the etching tank 10 to achieve etching solution regeneration, and the embodiment of the present invention does not impose any specific limitation on this.

[0214] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0215] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrolysis current control method, characterized in that: The control method comprises: Obtaining a detected oxidation-reduction potential value of the etching solution; Obtaining an electrolysis current control signal according to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value; The electrolysis current value of the electrolytic cell is controlled according to the electrolysis current control signal.

2. The electrolysis current control method according to claim 1, characterized in that: Before obtaining the detected oxidation-reduction potential value of the etching solution, the method further includes: The target redox potential value is preset.

3. The electrolysis current control method according to claim 1, characterized in that: After controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal, the method further comprises: The chlorine gas or electrolyte generated by electrolysis in the electrolytic cell is recycled to the etching cell to achieve regeneration of the etching solution.

4. The electrolysis current control method according to claim 1, characterized in that: According to the difference between the detected redox potential value and the target redox potential value, an electrolysis current control signal is obtained, including: According to the difference between the detected oxidation-reduction potential value and the target oxidation-reduction potential value, the difference is processed by using a PID algorithm to obtain the electrolysis current control signal.

5. The electrolysis current control method according to claim 1, characterized in that: Before controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal, the method further comprises: The detected electrolysis current value of the electrolytic cell is obtained.

6. The electrolysis current control method according to claim 5, characterized in that: The electrolysis current control signal includes a first electrolysis current value, and the first electrolysis current value is used to control the electrolysis current value of the electrolytic cell.

7. The electrolysis current control method according to claim 5, characterized in that: The electrolysis current control signal includes a first electrolysis current error value, and the first electrolysis current error value is used to control the electrolysis current value of the electrolytic cell together with the detected electrolysis current value.

8. The electrolysis current control method according to claim 6, characterized in that: Controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal comprises: Determine whether a first difference between the first electrolysis current value and the detected electrolysis current value is greater than 0; When the first difference is greater than 0, the electrolysis current value of the electrolytic cell is increased until the detected electrolysis current value is equal to the first electrolysis current value.

9. The electrolysis current control method according to claim 7, characterized in that: Controlling the electrolysis current value of the electrolytic cell according to the electrolysis current control signal comprises: Determine whether the first electrolysis current error value is greater than 0; When the first electrolysis current error value is greater than 0, the electrolysis current value of the electrolytic cell is increased until the detected electrolysis current value is equal to a second electrolysis current value, wherein the second electrolysis current value is the sum of the first electrolysis current value and the first electrolysis current error value.

10. An electrolytic current control system, characterized in that: include: An electrolytic cell, used for electrolyzing the etching solution after etching the printed circuit board; An oxidation-reduction potential sensor, used to detect the oxidation-reduction potential of the etching solution; A PID controller, the PID controller is connected to the oxidation-reduction potential value sensor, and is used to obtain an electrolysis current control signal according to a difference between the detected oxidation-reduction potential value and a target oxidation-reduction potential value; An electrolysis current controller is connected to the PID controller and the electrolytic cell respectively, and is used to control the electrolysis current of the electrolytic cell according to the electrolysis current control signal.

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