A PCB etching automatic control method

Abstract

The present invention relates to the technical field of PCB manufacturing, and in particular to a PCB etching automatic control method. The method comprises the following steps: when a release signal of an etching line is detected, the continuity of the release signal is determined, an exhaust valve is closed, a circulation pump and a feed pump of the corresponding etching line are started, etching liquid is fed into a reactor through a feed regulating valve by the feed pump, a sub-liquid pump and an ORP detection device are sequentially started, a circuit board to be etched is placed in an etching tank, and the etching liquid is pressed out of the etching tank through a discharge regulating valve using the pressure of the reactor to etch the circuit board; during the etching process, the discharge regulating valve controls the outflow of the etching liquid, and a sub-hydrometer built into the sub-liquid pump calculates the inflow of the sub-liquid and other chemical solutions based on the outflow of the etching liquid; when no release signal of the etching line is detected, the continuity of the no release signal is determined, and all operations of the etching line are stopped. The present invention can reduce the fluctuation range of production parameters and meet high etching requirements for circuit boards.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB manufacturing, and in particular to a PCB etching automatic control method. Background Art

[0002] In the manufacturing process of PCBs (printed circuit boards), etching technology uses chemical reactions to remove unwanted parts of copper foil to form circuit patterns. During the etching process, a protective film (dry film or photoresist) is first applied to the surface of the copper foil, and then the desired circuit pattern is exposed on the copper foil using a photolithography machine.

[0003] The PCB etching process involves controlling multiple parameters, such as the amount of oxidant added, hydrochloric acid concentration, reaction temperature, and reaction time. Variations in these parameters significantly impact regeneration efficiency and product quality. To achieve precise control and improve both efficiency and quality, automated control technology is necessary. However, existing automated control technologies exhibit wide fluctuations in production parameters, making them inadequate for the production of circuit boards requiring high-precision etching. Therefore, the present invention proposes an automated PCB etching method. Summary of the Invention

[0004] To solve the above problems, the present invention provides a PCB etching automatic control method, which can reduce the fluctuation range of production parameters and meet the high etching requirements of circuit boards.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A PCB etching automatic control method, comprising:

[0007] When the etching line release signal is detected, after judging the continuity of the release signal, the tail gas valve is closed, the circulation pump and feed pump of the corresponding etching line are started, the discharge regulating valve and the feed regulating valve are opened, and the etching solution is fed into the reactor through the feed regulating valve by the feed pump;

[0008] Turn on the sub-liquid pump and the ORP detection device, place the circuit board to be etched into the etching tank, and use the pressure of the reactor to press the etching liquid through the discharge regulating valve into the etching tank to etch the circuit board;

[0009] During the etching process, the discharge regulating valve controls the outflow of the etching liquid, and the sub-hydrometer built into the sub-liquid pump calculates the inflow of the sub-liquid and the inflow of other chemicals according to the outflow of the etching liquid;

[0010] When it is detected that the etching line has no plate release signal, after judging the continuity of the no plate release signal, all operations of the etching line are stopped.

[0011] The invention determines whether the production is continuous by judging the continuity of the power-on release signal, thereby reducing the waste of liquid medicine and energy consumption, avoiding frequent start and stop and affecting the life of the equipment.

[0012] The hydrometer is used to calculate the inflow of sub-liquid and other chemicals according to the outflow of etching liquid, so as to achieve the balance of input and output, keep the composition of online etching liquid stable, reduce the fluctuation range of production parameters, and improve the etching rate.

[0013] Preferably, after turning on the sub-liquid pump and the ORP detection device, the method further comprises:

[0014] Determine the hydrochloric acid concentration and ORP in the reactor using a hydrochloric acid meter and the ORP detection device respectively;

[0015] If the hydrochloric acid concentration is lower than a first preset hydrochloric acid concentration, starting the hydrochloric acid pump;

[0016] If the ORP is lower than a first preset ORP value, the additive pump is started.

[0017] A hydrochloric acid meter can provide relatively accurate hydrochloric acid concentration readings, helping to ensure that the hydrochloric acid concentration in the reactor is within the ideal operating range, thereby avoiding production problems or safety hazards caused by excessively high or low concentrations.

[0018] Combining data from the hydrochloric acid meter and ORP detection device enables intelligent control of the reactor. When the hydrochloric acid concentration or ORP value reaches the preset range, the hydrochloric acid pump and the dosing pump are automatically started, ensuring the safety and stability of the production process.

[0019] Preferably, before turning on the sub-liquid pump and the ORP detection device, the method further comprises:

[0020] The startup state of the etching line is determined, and the sub-liquid and the ORP detection device are turned on after a certain delay.

[0021] When the etching line is not fully started or is in an unstable state, directly turning on the sub-liquid pump and the ORP detection device may cause safety problems. This method can improve the safety of the etching line.

[0022] If the etching line is not operating normally, turning on the sub-liquid pump and ORP detection device may result in unnecessary energy consumption and chemical waste.

[0023] Preferably, the sub-hydrometer built into the sub-liquid pump calculates the inflow of the sub-liquid and the inflow of other chemicals according to the outflow of the etching liquid, including:

[0024] Calculate the inflow of the sub-liquid by using a hydrometer, calculate the inflow of hydrochloric acid by using the inflow of the sub-liquid, and calculate the inflow of the additive by using the ORP value and the inflow of the sub-liquid;

[0025] According to the calculation results, the amounts of sub-liquid, hydrochloric acid and additive flowing into the reactor are controlled respectively by the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve.

[0026] By measuring the density or specific gravity of the sub-liquid and combining it with a pre-set density-flow relationship, the inflow rate of the sub-liquid can be accurately calculated. This helps ensure that the sub-liquid concentration in the reactor is within the ideal range, thereby improving product quality and reaction efficiency.

[0027] The amount of hydrochloric acid added is calculated based on the amount of the sub-liquid and the pre-set ratio. This calculation method based on the actual inflow ensures that the amount of hydrochloric acid added matches the sub-liquid, thus maintaining the stability and efficiency of the reaction.

[0028] The ORP value reflects the intensity and direction of the redox reaction in the solution and is closely related to the amount of additive added. By combining the ORP value and the amount of sub-liquid inflow to calculate the amount of additive inflow, we can ensure that the amount of additive added matches the reaction progress, thereby improving product quality and yield.

[0029] Preferably, after controlling the amount of sub-liquid, hydrochloric acid and additive flowing into the reactor respectively through the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve according to the calculation results, the method further comprises:

[0030] Re-evaluate the hydrochloric acid concentration and ORP in the reactor;

[0031] If the hydrochloric acid concentration is higher than a second preset hydrochloric acid concentration value, stopping the hydrochloric acid pump;

[0032] If the ORP is higher than a second preset ORP value, the additive pump is stopped.

[0033] Real-time re-evaluation of hydrochloric acid concentration and ORP value can provide immediate feedback, ensuring that the chemical environment in the reactor is always under control. By precisely controlling the inflow of hydrochloric acid and additives, the reaction process can be ensured to proceed under optimal conditions, thereby improving product quality and consistency.

[0034] Preferably, after closing the tail gas valve and starting the circulation pump and feed pump of the corresponding etching line, the method further comprises:

[0035] Starting the oxidation kettle pump and determining the pressure value in the oxidation kettle;

[0036] If the pressure value is less than the first preset pressure value, the oxygen regulating valve is started to automatically adjust the pressure value through the oxygen regulating valve until the pressure value reaches a stable pressure value;

[0037] If the pressure value is less than the second preset pressure value, the system automatically determines that the oxygen in the liquid oxygen bottle is empty and automatically switches to the spare liquid oxygen bottle for operation.

[0038] When the pressure inside the oxidation kettle falls below the first preset pressure value, the oxygen regulating valve is activated to automatically adjust the pressure to ensure that the oxidation kettle operates within the optimal operating pressure range. This precise pressure control helps improve product quality and production efficiency.

[0039] The oxygen regulating valve's automatic adjustment function reduces manual operation and improves production efficiency. Based on the preset pressure value, the oxygen regulating valve can quickly respond and adjust the pressure to maintain a stable pressure in the oxidation reactor.

[0040] Preferably, the step of starting the oxidation kettle pump and determining the pressure value in the oxidation kettle further comprises:

[0041] When the pressure is greater than the regulated value, close the oxygen regulating valve;

[0042] When the pressure exceeds the safety setting value, the exhaust valve automatically opens and triggers the alarm system.

[0043] The automatic opening of the exhaust valve can quickly release excessive pressure, effectively preventing safety accidents such as equipment damage, leakage and even explosion caused by excessive pressure.

[0044] The triggered alarm system can immediately notify operators or relevant personnel, ensuring that they can take necessary measures at the first time to further ensure production safety.

[0045] Preferably, the other inflows of the medicinal solution include the inflow of hydrochloric acid and the inflow of additives.

[0046] Preferably, after controlling the amount of sub-liquid, hydrochloric acid and additive flowing into the reactor respectively through the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve according to the calculation results, the method further comprises:

[0047] When the temperature of the reactor is lower than the set value, the electric heating system will automatically start heating, and when it reaches the set value, the electric heating will automatically stop.

[0048] By automatically starting and stopping the electric heating system, the temperature inside the reactor can be precisely controlled to ensure that it is maintained within the set temperature range.

[0049] A stable temperature environment helps ensure consistency and reproducibility of chemical reactions, thereby improving product quality and purity and avoiding incomplete reactions or the production of by-products due to temperature fluctuations.

[0050] Preferably, the inflow of the additive is 2% of the inflow of the sub-liquid.

[0051] The beneficial effects of the present invention are:

[0052] 1. The etching line automatically switches on and off the circulation pump according to the continuity of the board release signal to reduce energy consumption during the production process. By judging the continuity of the board release signal when the machine is turned on, it can be used to determine whether the production is continuous, thereby reducing the waste of chemicals and energy consumption, avoiding frequent start and stop, and affecting the life of the equipment.

[0053] 2. By precisely controlling the inflow of the sub-liquid, the waste of raw materials caused by excessive addition can be avoided. At the same time, the control of the inflow of other potions can also ensure the chemical balance in the production process and reduce unnecessary waste.

[0054] The hydrometer is used to calculate the inflow of sub-liquid and other chemicals according to the outflow of etching liquid, so as to achieve the balance of input and output, keep the composition of online etching liquid stable, reduce the fluctuation range of production parameters, and improve the etching rate.

[0055] 3. When etching circuit boards of different thicknesses, the hydrometer will have a certain slight change. The inflow of sub-liquid and other chemicals will be automatically adjusted in time through the feedback of the hydrometer, and pumped out to the reactor through the corresponding pump to control the stability of the etching solution performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a flowchart of the automatic etching control in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0057] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0058] See also Figure 1 As shown, the present invention relates to a PCB etching automatic control method.

[0059] Example 1

[0060] When one or more etching lines are detected to start up and release the board signal, the etching production line start roller signal switch is used to make a delayed response to determine whether the start-up and release board signal is detected. The delay is 2 minutes. If the release board signal is the only signal within 2 minutes, the etching automatic control device is started with one button.

[0061] Close the exhaust valve and start the first-level circulation pump of the oxidation regeneration kettle in sequence. When it is detected that only one etching line has started and released the board signal, only the first-level circulation pump needs to be turned on. When the etching line starts and releases the board signal is detected, the circulation pump and feed pump of the corresponding etching line are turned on, and the first / second line etching start status is judged. After a delay of five minutes, the sub-liquid pump is started and the valve corresponding to the sub-liquid pump is opened. A hydrometer is provided in the sub-liquid pump.

[0062] Start the oxidation kettle pump and determine the pressure value in the reactor. The specific first preset pressure value can be 0.15MPa. When the pressure value of the reactor is less than 0.15MPa, open the oxygen valve and use the oxygen regulating valve to automatically control the reactor pressure to stabilize at the set value; when the pressure is greater than 0.15MPa, close the oxygen regulating valve. When the pressure is lower than the set value, increase the opening of the oxygen regulating valve. When the pressure is lower than the lower limit, the system automatically determines that the oxygen in the liquid oxygen bottle is empty and automatically switches to the spare liquid oxygen bottle for production. The pressure change of the automatic control device is used to intelligently control the start and stop of the oxygen bottle.

[0063] When the pressure in the reactor is adjusted to a stable pressure, open the corresponding etching line feed pump, as well as the feed regulating valve and discharge regulating valve corresponding to the feed pump, open the corresponding etching line sub-liquid pump and ORP detection device, and use the feed pump to let the etching liquid enter the reactor through the feed regulating valve.

[0064] Oxidation-Reduction Potential (ORP) is an electrochemical parameter that measures the redox capacity of a solution. It represents the macroscopic redox properties of all substances in the solution. Higher ORP values indicate a more oxidizing solution; lower ORP values indicate a more reducing solution.

[0065] Placing the circuit board to be etched into the etching tank, and using the pressure of the reactor to press the etching solution through the discharge regulating valve into the etching tank to etch the circuit board;

[0066] During the etching process, the discharge regulating valve controls the outflow of the etching liquid, and the sub-hydrometer built into the sub-liquid pump calculates the inflow of the sub-liquid and the inflow of other chemicals according to the outflow of the etching liquid to ensure stable control of the liquid level of the reactor.

[0067] When etching different thickness circuit boards on different lines, the hydrometer will show slight variations. Taking the average hydrometer value, the regeneration sub-liquid is calculated based on the specific gravity logic to determine the flow rate. This is then pumped to the oxidation regeneration kettle via the sub-liquid pump, where the sub-liquid regulating valve adjusts the flow rate. This specific gravity control ensures stable etching solution performance.

[0068] This application can intelligently produce boards of different thicknesses according to the production line, and automatically and timely adjust the production line linkage circulation volume and sub-liquid addition amount through hydrometer feedback. It is the first control system in the industry that can arbitrarily switch to different types of circuit board production needs on the same etching line at irregular intervals.

[0069] When one of the etching lines stops production, the etching line feed pump and cut-off valve are closed after a delay of 5 minutes after detecting that there is no circuit board signal, and the oxidation regeneration kettle discharges the material to the discharge regulating valve and feed regulating valve of the etching line.

[0070] When it is detected that the two etching lines have stopped production and the signal of no circuit board is detected, the feed pumps and cut-off valves of the two etching lines are closed after a delay of 5 minutes, the reactor discharges the material to the two etching lines to adjust the valves, and the sub-liquid pump and sub-liquid regulating valve are closed, the hydrochloric acid pump and hydrochloric acid regulating valve are closed, the additive pump and additive regulating valve are closed, the first and second level circulation pumps of the reactor are closed, and the oxygen regulating valve is closed to achieve one-button shutdown.

[0071] Example 2

[0072] In this embodiment, the sub-liquid, hydrochloric acid and additives may be provided as follows:

[0073] This application is 20% higher than the existing industry ORP value. It achieves the balance of input and output through the intelligent control of the hydrometer, maintains the stability of the online etching liquid composition, and increases the etching rate. It does not need to rely on the spray pressure of the etching line to increase the etching rate. High spray pressure will damage the membrane and easily cause over-etching of the etching line.

[0074] The amount of hydrochloric acid required for oxidation can be indirectly calculated by the amount of sub-liquid added. When the minimum acidity maintained on the etching line is less than 0.6 mol / l, the hydrochloric acid pump adds 110% of the calculated value through the regulating valve; when the hydrochloric acid acidity increases to the normal 0.7 mol / l, the hydrochloric acid pump adds 100% of the calculated value through the hydrochloric acid regulating valve; when the hydrochloric acid acidity exceeds the normal 0.8 mol / l, the hydrochloric acid pump adds 90% of the calculated value through the regulating valve; in this way, the hydrochloric acid added acidity is controlled to be stable at 0.6-0.8 mol / l.

[0075] The amount of additive added is 2‰ of the amount of sub-liquid added, and is automatically controlled by the metering pump frequency conversion. When the ORP value (redox potential) on the etching line is greater than 590mv, the additive pump stops adding. When the ORP value on the etching line is less than 580mv, the additive pump starts adding. Automatic addition of additives is achieved through the ORP value.

[0076] Hydrometer calculates sub-liquid inflow: By measuring the density or specific gravity of the sub-liquid and combining it with a preset density-flow relationship, the sub-liquid inflow can be accurately calculated. This helps ensure that the sub-liquid concentration in the reactor is within the ideal range, thereby improving product quality and reaction efficiency.

[0077] Calculate the amount of hydrochloric acid inflow based on the inflow of the sub-liquid: The inflow of hydrochloric acid needs to be calculated based on the inflow of the sub-liquid and the preset ratio. This calculation method based on the actual inflow can ensure that the amount of hydrochloric acid added matches the sub-liquid, thereby maintaining the stability and efficiency of the reaction.

[0078] Calculating additive inflow based on ORP and sub-liquid inflow: The ORP value reflects the intensity and direction of the redox reaction in the solution and is closely related to the amount of additive added. By combining the ORP value and sub-liquid inflow to calculate the additive inflow, you can ensure that the additive amount is matched to the reaction progress, thereby improving product quality and yield.

[0079] After controlling the amount of sub-liquid, hydrochloric acid and additive flowing into the reactor through the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve, respectively, re-determining the hydrochloric acid concentration and ORP in the reactor;

[0080] If the hydrochloric acid concentration is higher than the second preset hydrochloric acid concentration value, the hydrochloric acid pump is stopped; if the ORP is higher than the second preset ORP value, the additive pump is stopped.

[0081] The amount of sub-liquid added is precisely controlled by a hydrometer, the amount of hydrochloric acid added is controlled by the amount of sub-liquid added, the actual addition ratio range of hydrochloric acid is accurately determined by the acidity meter, and the amount of catalyst added is controlled by the ORP size and the amount of sub-liquid added. The above means are used to control and ensure the steady-state production of production parameters, so that the parameter fluctuation range is small, and the high-precision etching requirements of circuit boards are achieved, which is better than other current etching addition systems (the upper and lower limit control range is large, resulting in large fluctuations in production parameters).

[0082] Example 3

[0083] In some embodiments, the specific amounts of the seed solution, hydrochloric acid, and additives will depend on various factors, such as the material being etched, the desired etch depth, the etch rate, and the control of undercuts. The above is a generalized setting method based on parameters and is not a fixed standard. In actual production, adjustments may be made based on specific circumstances. These may serve as alternative solutions for this application.

[0084] Example 4

[0085] Preferably, in some embodiments:

[0086] 1. When the system pressure of the oxidation regeneration kettle exceeds the ultra-high limit safety setting value, the tail gas valve will automatically open to release the pressure to the system pressure of 0, and trigger the alarm to shut down the system with one button to prevent safety hazards in the oxidation regeneration kettle system.

[0087] 2. When the pressure of the oxidation regeneration kettle system is lower than the ultra-low safety setting value, an alarm will be triggered and the machine will be shut down with one button, indicating that the oxygen has been used up or there is other failure in the oxygen facility, which cannot meet the normal etching and board production needs.

[0088] 3. When the liquid level of the oxidation regeneration kettle system exceeds the upper limit setting value, it will trigger an alarm and shut down the system with one button. The system can only be reset and started with one button after manual confirmation and adjustment of the liquid level.

[0089] 4. When the liquid level of the oxidation regeneration kettle system is lower than the lower limit setting value, an alarm will be triggered and the system will be shut down with one button. The system can only be reset and started with one button after manual confirmation and adjustment of the liquid level.

[0090] 5. When one or more etching line feed pumps or valves fail, an alarm will be triggered and the machine will be shut down with one button. The machine can only be reset and started with one button after manual confirmation of the fault.

[0091] Example 5

[0092] During the PCB etching process, temperature control is crucial to ensuring etching results and product quality. Temperature is a key factor affecting the etching rate. Generally speaking, increasing the temperature can accelerate the chemical reaction and increase the etching rate.

[0093] During the etching process, the temperature of the etching liquid should be monitored regularly to ensure that it is within the set temperature range. A thermometer or temperature sensor can be used in the reactor to monitor the temperature in real time and record the data. The heating or cooling parameters of the etching machine can be adjusted in time according to the temperature of the etching liquid and the etching effect.

[0094] When the temperature of the reactor is lower than the set value, the electric heating system will automatically start heating, and when it reaches the set value, the electric heating will automatically stop.

[0095] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A PCB etching automatic control method, characterized in that: include: When the etching line release signal is detected, after judging the continuity of the release signal, the tail gas valve is closed, the circulation pump and feed pump of the corresponding etching line are started, the discharge regulating valve and the feed regulating valve are opened, and the etching solution is fed into the reactor through the feed regulating valve by the feed pump; Turn on the sub-liquid pump and the ORP detection device, place the circuit board to be etched into the etching tank, and use the pressure of the reactor to press the etching liquid through the discharge regulating valve into the etching tank to etch the circuit board; During the etching process, the discharge regulating valve controls the outflow of the etching liquid, and the sub-hydrometer built into the sub-liquid pump calculates the inflow of the sub-liquid and the inflow of other chemicals according to the outflow of the etching liquid; When it is detected that the etching line has no plate release signal, after judging the continuity of the no plate release signal, all operations of the etching line are stopped; After the sub-liquid pump and the ORP detection device are turned on, the method further includes: Determine the hydrochloric acid concentration and ORP in the reactor using a hydrochloric acid meter and the ORP detection device respectively; if the hydrochloric acid concentration is lower than a first preset hydrochloric acid concentration value, start the hydrochloric acid pump; If the ORP is lower than a first preset ORP value, starting the additive pump; The sub-hydrometer built into the sub-liquid pump calculates the inflow of the sub-liquid and the inflow of other chemicals according to the outflow of the etching liquid, including: Calculate the inflow of the sub-liquid by a hydrometer, calculate the inflow of hydrochloric acid by the inflow of the sub-liquid, and calculate the inflow of the additive by the ORP size and the inflow of the sub-liquid; According to the calculation results, the amounts of sub-liquid, hydrochloric acid and additive flowing into the reactor are controlled respectively by the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve.

2. The PCB etching automatic control method according to claim 1, wherein: Before turning on the sub-liquid pump and the ORP detection device, the method further comprises: The startup status of the etching line is determined, and the sub-liquid and the ORP detection device are turned on after a certain delay.

3. The PCB etching automatic control method according to claim 1, wherein: After controlling the amount of sub-liquid, hydrochloric acid and additive flowing into the reactor respectively through the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve according to the calculation results, the method further includes: Re-evaluate the hydrochloric acid concentration and ORP in the reactor; If the hydrochloric acid concentration is higher than a second preset hydrochloric acid concentration value, stopping the hydrochloric acid pump; If the ORP is higher than a second preset ORP value, the additive pump is stopped.

4. The PCB etching automatic control method according to claim 1, characterized in that: After closing the tail gas valve and starting the circulation pump and feed pump of the corresponding etching line, the method further includes: Starting the oxidation kettle pump and determining the pressure value in the oxidation kettle; If the pressure value is less than the first preset pressure value, the oxygen regulating valve is started to automatically adjust the pressure value through the oxygen regulating valve until the pressure value reaches a stable pressure value; If the pressure value is less than the second preset pressure value, the system automatically determines that the oxygen in the liquid oxygen bottle is empty and automatically switches to the spare liquid oxygen bottle for operation.

5. The PCB etching automatic control method according to claim 4, characterized in that: The step of starting the oxidation kettle pump and determining the pressure value in the oxidation kettle further comprises: When the pressure is greater than the regulated value, close the oxygen regulating valve; When the pressure is greater than the safety set value, the exhaust valve automatically opens and triggers the alarm system.

6. The PCB etching automatic control method according to claim 1, characterized in that: The inflow of other chemical solutions includes the inflow of hydrochloric acid and the inflow of additives.

7. The PCB etching automatic control method according to claim 1, characterized in that: After the amount of the sub-liquid, hydrochloric acid and additive flowing into the reactor is controlled by the sub-liquid regulating valve, the hydrochloric acid regulating valve and the additive regulating valve respectively according to the calculation results, the method further comprises: When the temperature of the reactor is lower than the set value, the electric heating system will automatically start heating, and when it reaches the set value, the electric heating will automatically stop.

8. The PCB etching automatic control method according to claim 1, characterized in that: The inflow amount of the additive is 2% of the inflow amount of the sub-liquid.

Images