Precise pulse constant-current device for electrochemical surface treatment of micron-scale materials

Abstract

The invention discloses a precise pulse constant-current device for electrochemical surface treatment of a micron-scale material, and belongs to the technical field of electrochemical equipment. By arranging the power supply system, the electrolyte system and the control system, the control system controls the power supply system to perform electrochemical operation on a to-be-treated workpiece in the electrolyte system; wherein the power supply system comprises an electrolyte heating system, an electrolyte circulating system and a constant-current pulse circuit; the electrolyte heating system is used for heating the electrolyte in the electrolyte system according to the heating control instruction; and the constant-current pulse circuit is used for controlling the constant-current source chip to generate constant current to act on the workpiece to be processed according to the PWM signal of the control system. The constant-current pulse circuit is provided with a gate drive protection branch circuit, so that clutter current can be quickly discharged, and the stability of a signal reference is guaranteed; and the influence of electromagnetic interference and power supply fluctuation on the driving signal is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply equipment, in particular to a precision pulse constant current device for micro-scale material electrochemical surface treatment. BACKGROUND

[0002] With the rapid development of micro-nano manufacturing, precision electronics, biomedical materials and other fields, the application of micro-scale materials (such as micro-scale metal wires, thin films, micro-structure components, etc.) is becoming more and more widespread, and their surface properties (such as corrosion resistance, electrical conductivity, biocompatibility, etc.) directly affect the reliability and service life of the end product. Electrochemical surface treatment technology (including electrochemical polishing, electrochemical operation, electrolytic etching, etc.) has become one of the core means to improve the surface properties of micro-scale materials due to its high processing precision, excellent surface quality, and strong process controllability. The unique structure of micro-scale materials determines the particularity of the electrochemical working process: on the one hand, the effective reaction area of the material is only millimeter or micrometer, in order to avoid local current concentration leading to material surface ablation, grain boundary corrosion or structure damage, the required current density is usually controlled in the low level range of 1-100 On the other hand, combined with the constraints of low current density and micro-scale reaction area, the actual input power requirement of the entire electrochemical treatment process is usually only milliwatt to watt, and the stability of the current and the accuracy of the pulse parameters are extremely high. For example, a small current fluctuation (such as ±1mA or more) may cause surface roughness to exceed the standard, film thickness to be uneven, and other quality problems, which seriously affect the performance of the material. However, the electrochemical treatment power supply widely used in the current industry is generally designed for macro materials (such as plates, pipes, large parts), and its power level is generally in the range of dozens of watts to thousands of watts. The core design goal is to meet the processing needs of large current and high power, which is difficult to adapt to the processing scene of micro-scale materials, thereby limiting the uniformity and refinement of material surface treatment. Therefore, there is an urgent need in the art to develop a milliampere precision pulse constant current power supply device specially designed for micro-scale material electrochemical treatment. This device should be optimized from the bottom up for low current, low power, high precision, and fast response application scenarios, and fundamentally fill the gap in the current market in terms of special and cost-effective power supply. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a precision pulse constant current device for micro-scale material electrochemical surface treatment, which has novel and reasonable design, strong anti-interference ability, good electrochemical operation effect, and is convenient to use.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is: A precision pulse constant current device for micro-scale material electrochemical surface treatment, comprising a power supply system, an electrolyte system and a control system; The control system controls the power supply system to perform electrochemical operation on the workpiece to be processed in the electrolyte system; The workpiece to be processed is composed of micro-scale materials; The power supply system comprises an electrolyte heating system, an electrolyte circulation system, and a constant current pulse circuit; the electrolyte heating system is used to heat the electrolyte in the electrolyte system according to the heating control instruction; The electrolyte circulation system controls the circulation of the electrolyte in the electrolyte tank through a circulating pump; The constant current pulse circuit is used to control the constant current source chip to generate a constant current acting on the workpiece to be processed according to the PWM signal of the control system; The constant current pulse circuit comprises a constant current source chip and a MOSFET; an external PWM signal is connected to the gate of the MOSFET through a drive protection branch, the gate of the MOSFET is connected to the ground through a circuit, and the drain of the MOSFET is connected to the control pin of the constant current source chip through a voltage dividing network; the source of the MOSFET is connected to the ground through a sampling resistor; The drive protection branch comprises a diode, a third resistor, a fourth resistor and a fifth resistor; the diode and the fifth resistor are connected in series, and then connected in reverse parallel with the fourth resistor; the anode of the diode and the common end of the fourth resistor are used to connect the PWM signal, and the common end of the fourth resistor and the fifth resistor is connected with the gate of the MOSFET and one end of the third resistor, respectively, and the other end of the third resistor is connected to the ground.

[0005] Further, the control pin of the constant current source chip comprises a SET pin and an OUT pin, and the voltage dividing network comprises a second resistor, a seventh resistor and an adjustable resistor; The seventh resistor and the adjustable resistor are connected in series, one end of the seventh resistor is connected with the SET pin of the constant current source chip, one end of the adjustable resistor is connected with one end of the second resistor after being connected in common, and the other end of the second resistor is connected with the OUT pin of the constant current source chip; the control system determines the current value of the workpiece to be processed according to the voltage signal between the sampling resistor; The control system compares the current value of the workpiece to be processed with the preset constant current value, if the current value is greater than the preset constant current value, the resistance value of the adjustable resistor is increased, and if the current value is less than the preset constant current value, the resistance value of the adjustable resistor is decreased, so as to realize the constant current control of the workpiece to be processed.

[0006] Further, the control system is used for: detecting the voltage of the workpiece to be processed, and issuing a stop electrochemical operation control instruction when the voltage amplitude decreases by more than X% or the voltage abnormally rises within a set time; the set time is 2-5 sampling periods, and X% is 10%-60%; the voltage abnormally rising refers to that the voltage amplitude increases by more than 40% within N sampling periods, and N is 3-8.

[0007] Further, the current range of the constant current control is 50-200 mA.

[0008] Further, the process of the control system controlling the power supply system to perform electrochemical operation on the workpiece to be processed in the electrolyte system is: the control system issues a heating control instruction, the control system issues a PWM signal when the heating system heats the electrolyte to a set temperature, and the control system issues a stop electrochemical operation control instruction when the running time reaches a set value after the PWM signal is issued, so as to complete the electrochemical operation on the workpiece to be processed.

[0009] Further, the control system is used for: detecting the temperature data of the electrolyte, controlling the electrolyte heating system to increase the heating power when the temperature of the electrolyte is lower than the set temperature by 3℃, controlling the electrolyte heating system to decrease the heating power when the temperature of the electrolyte is higher than the set temperature by 3℃, and controlling the electrolyte heating system to stop working when the temperature deviates from the set temperature by ±5℃.

[0010] Further, the control system comprises a PLC and a pulse generation control circuit, and the pulse generation control circuit is used for generating a PWM signal. Compared with the prior art, the present application has the following advantages: The present application comprises a power supply system, an electrolyte system and a control system, the control system controls the power supply system to perform electrochemical operation on the workpiece to be processed in the electrolyte system, the power supply system comprises an electrolyte heating system, an electrolyte circulation system and a constant current pulse circuit, the electrolyte heating system is used for heating the electrolyte in the electrolyte system according to a heating control instruction, and the constant current pulse circuit is used for controlling a constant current source chip to generate a constant current acting on the workpiece to be processed according to a PWM signal of the control system. The constant current pulse circuit is provided with a gate drive protection branch, which realizes rapid discharge of the stray current, guarantees the stability of the signal reference, and specifically, a third resistor is arranged in front of the gate to limit the current, filter the high-frequency noise and avoid the large current impact on the MOSFET; a diode and a fifth resistor are connected in series, and then are connected in reverse parallel with a fourth resistor, which clamps the gate potential, suppresses the negative peak, offsets the transmission noise and prevents the waveform distortion; the PWM signal waveform is ensured to be complete and the transmission is ensured to be reliable, and the influence of electromagnetic interference and power supply fluctuation on the driving signal is avoided.

[0011] The technical solutions of the present application are further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 This is a schematic diagram of an embodiment of the precision pulse constant current device for electrochemical surface treatment of micron-scale materials according to the present invention; Figure 2 This is a production line structure diagram of an embodiment of the precision pulse constant current device for electrochemical surface treatment of micron-scale materials according to the present invention; Figure 3 This is a circuit diagram of the constant current pulse circuit of an embodiment of the precision pulse constant current device for electrochemical surface treatment of micron-scale materials according to the present invention; Figure 4 This is a control block diagram of the control system of an embodiment of the precision pulse constant current device for electrochemical surface treatment of micron-scale materials according to the present invention; Figure 5 This is a flowchart illustrating the control system operation of an embodiment of the precision pulse constant current device for electrochemical surface treatment of micron-scale materials according to the present invention. Explanation of reference numerals in the attached figures: 1. Power supply system; 2. Electrolyte system; 3. Workpiece to be processed; 4. Control system; 5. Electrolyte heating system; 6. Electrolyte circulation system; 7. Constant current pulse circuit; 8. PLC; 9. Pulse generation control circuit; 10. Electrolyte tank; 11. Heating component; 12. Temperature measuring component; 13. Magnetic pump; 14. Anode. Detailed Implementation

[0013] Example of a precision pulsed constant current device for electrochemical surface treatment of micron-scale materials: like Figures 1-5 As shown, the precision pulsed constant current device for electrochemical surface treatment of micron-scale materials includes a power supply system 1, an electrolyte system 2, and a control system 4. The control system 4 controls the power supply system 1 to perform electrochemical operations on the workpiece 3 to be treated in the electrolyte system 2. This electrochemical operation is electroplating; this embodiment uses tungsten wire nickel plating as an example. The control system 4 includes a PLC 8 and a pulse generation control circuit 9, which generates PWM signals. The frequency of the PWM signal is 100Hz to 10kHz, and the duty cycle can be set from 1% to 99%.

[0014] Electrolyte system 2 includes an electrolyte and an electrolyte tank 10. The workpiece 3 to be treated will undergo electrochemical processing within the electrolyte. The electrolyte used is nickel sulfamate for nickel plating electrochemical processing, and is injected into the electrolyte tank 10 to the set level.

[0015] like Figure 2As shown, the electrolyte circulation pipeline passes through the electrolyte tank 10 and the circulation pump, realizing the circulation of the electrolyte in the electrolyte tank 10, wherein the circulation pump adopts a magnetic pump 13; the anode 14 and the cathode are both below the electrolyte level. During the electrochemical operation, the workpiece 3 to be treated serves as the cathode, and the independently arranged inert electrode serves as the anode 14.

[0016] The above-mentioned power supply system 1 comprises an electrolyte heating system 5, an electrolyte circulation system 6 and a constant current pulse circuit 7.

[0017] The electrolyte heating system 5 is used for heating the electrolyte in the electrolyte system 2 according to a heating control instruction. The electrolyte heating system 5 comprises a heating component 11 and a temperature measuring component 12; the heating component 11 is used for heating the electrolyte; and the temperature measuring component 12 is used for detecting the electrolyte temperature.

[0018] The electrolyte circulation system 6 controls the circulation of the electrolyte in the electrolyte tank 10 of the electrolyte system 2 through the circulation pump. Specifically, the electrolyte circulation system 6 draws the electrolyte from the bottom of the electrolyte tank 10 through a pipeline, and returns the electrolyte from the top of the electrolyte tank 10 after filtration, so as to avoid local concentration difference; wherein the filtration adopts a 10 μm filter core. The circulation flow rate is set to 2 L / min.

[0019] The constant current pulse circuit 8 is used for controlling the constant current source chip to generate a constant current acting on the workpiece 3 to be treated according to the PWM signal of the control system 4.

[0020] As shown in the figure, the constant current pulse circuit 8 comprises a constant current source chip, a MOSFET, an adjustable resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sampling resistor, a seventh resistor, a diode and a 24V power supply. Figure 3 Figure 3 The first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sampling resistor R6 and the seventh resistor R7 correspond to the adjustable resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, the sampling resistor and the seventh resistor respectively; the diode D1 is a Schottky diode; the MOSFET Q1 is a MOSFET; and VCC is a 24V power supply. The first resistor R1 is selected to be 15 kΩ, the value is 10 kΩ, the second resistor R2 and the seventh resistor R7 are selected to be 1 Ω and 5 kΩ respectively, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 are respectively 10 kΩ, 10 Ω and 5.1 Ω, and the diode D1 is selected to be a Schottky diode.

[0021] Specifically, the constant current pulse circuit 8 comprises a constant current source chip and a MOSFET; an external PWM signal is connected to the gate of the MOSFET through a drive protection branch, the gate of the MOSFET is connected to the ground through a circuit, and the drain of the MOSFET is connected to the control pin of the constant current source chip through a voltage dividing network; and the source of the MOSFET is connected to the ground through a sampling resistor.

[0022] ​The drive protection branch includes a diode, a third resistor, a fourth resistor and a fifth resistor, the diode is connected in series with the fifth resistor, and then is connected in reverse parallel with the fourth resistor, the positive electrode of the diode and the common flow end of the fourth resistor are used for inputting a PWM signal, the common flow end of the fourth resistor and the fifth resistor is connected with the gate of the MOSFET and one end of the third resistor respectively, and the other end of the third resistor is grounded.

[0023] The control pin of the constant current source chip includes a SET pin and an OUT pin, and the voltage dividing network includes a second resistor, a seventh resistor and an adjustable resistor; the seventh resistor and the adjustable resistor are connected in series, one end of the seventh resistor is connected with the SET pin of the constant current source chip, one end of the adjustable resistor is connected with one end of the second resistor after the two ends of the second resistor are connected in common with the drain of the MOSFET, and the other end of the second resistor is connected with the OUT pin of the constant current source chip; the control system 4 determines the current value of the workpiece 3 to be processed according to the voltage signal between the two ends of the sampling resistor. The current of the sampling resistor is consistent with the current on the workpiece to be processed, and the voltage of the sampling resistor is collected to convert the current according to Ohm's law, and then the current of the workpiece to be processed is obtained.

[0024] The control system 4 compares the current value of the workpiece 3 to be processed with the preset constant current value, if the current value is greater than the preset constant current value, the resistance value of the adjustable resistor is increased, if the current value is less than the preset constant current value, the resistance value of the adjustable resistor is decreased, and the constant current control of the workpiece 3 to be processed is realized. The preset constant current value is 150mA. The current range of the constant current control is 50-200mA.

[0025] As shown in Figure 4 , 5 , the process that the control system 4 controls the power supply system 1 to perform electrochemical operation on the workpiece 3 to be processed in the electrolyte system 2 is as follows: the control system 4 issues a heating control instruction, when the heating system heats the electrolyte to a set temperature, the control system 4 issues a PWM signal, and when the running time of the PWM signal reaches a set value, the control system 4 issues a stop electrochemical operation control instruction, so as to complete the electrochemical operation on the workpiece 3 to be processed. The set temperature is 50℃, and the set temperature is generally 45-55℃. When the molybdenum wire is gold-plated, the sodium sulfite gold salt electrochemical operation liquid is used as the electrolyte, and the set temperature is 52℃, and the set temperature is generally 50-55℃. The set value is determined by the required electrochemical operation, and a small amount of electrochemical operation requires 1s. According to the nature of the experiment, the set value is generally between 20s and 1min, and in special cases, when a thick coating is needed, the set value is 10min to 1h.

[0026] The control system 4 is also used for detecting electrolyte temperature data, controlling the electrolyte heating system 5 to increase heating power when the electrolyte temperature is lower than the set temperature by 3 DEG C, controlling the electrolyte heating system 5 to reduce heating power when the electrolyte temperature is higher than the set temperature by 3 DEG C, and controlling the electrolyte heating system 5 to stop working when the temperature deviates from the set temperature by ±5 DEG C, thereby reducing the influence of temperature fluctuation on the electrochemical operation rate of the workpiece to be processed.

[0027] The control system 4 is used for detecting the voltage of the workpiece to be processed 3, and issuing a control instruction to stop electrochemical operation when the voltage drop amplitude exceeds X% or the voltage abnormally rises within a set time. The voltage abnormally rising refers to that the voltage rise amplitude exceeds 40% within N sampling periods, N is 3-8, the set time is 2-5 sampling periods, and X% is 10%-60%. Two examples are given here, the set time is 2 times the sampling period, and the corresponding X% is 10%; the set time is 4 times the sampling period, and the corresponding X% is 40%. The sampling period refers to the scanning period of the PLC, and the scanning period is generally 1-10 ms, and the scanning period is 5 ms here. The above-mentioned voltage abnormally rising generally corresponds to two cases, one is that the workpiece to be processed is suspended and has problems, is not soaked in the electrolyte, and the workpiece to be processed falls off, which can be avoided as much as possible; the other is that there is a contaminant on the workpiece to be processed or the anode, which may occur during preparation, and is mainly caused by poor electrolyte circulation.

[0028] The electrolyte system and the power supply system are linked, the power supply system automatically adjusts the pulse when the electrolyte temperature deviates from the preset value, and the influence on the coating of the workpiece to be processed is avoided.

[0029] The above is only a preferred embodiment of the present application, and does not limit the present application, any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical scheme of the present application.

Claims

1. A precision pulsed constant current device for microscale material electrochemical surface treatment, characterized in that: The power supply system (1), the electrolyte system (2) and the control system (4) are included. The control system (4) controls the power supply system (1) to perform electrochemical operation on the workpiece (3) to be processed in the electrolyte system (2). The workpiece (3) to be processed is composed of micron-scale materials. The power supply system (1) includes an electrolyte heating system (5), an electrolyte circulating system (6) and a constant current pulse circuit (7). The electrolyte heating system (5) is used to heat the electrolyte in the electrolyte system (2) according to a heating control instruction. The electrolyte circulating system (6) controls the circulation of the electrolyte in the electrolyte tank (10) of the electrolyte system (2) through a circulating pump. The constant current pulse circuit (7) is used to control the constant current source chip to generate a constant current acting on the workpiece (3) to be processed according to the PWM signal of the control system (4). The constant current pulse circuit (7) includes a constant current source chip and a MOSFET. The external PWM signal is connected to the gate of the MOSFET through a drive protection branch, the gate of the MOSFET is connected to the ground through a circuit, and the drain of the MOSFET is connected to the control pin of the constant current source chip through a voltage dividing network.

2. A precision pulsed constant current device for electrochemical surface treatment of materials on the micrometer scale according to claim 1, characterized in that: The drive protection branch includes a diode, a third resistor, a fourth resistor and a fifth resistor. The diode and the fifth resistor are connected in series, and then connected in reverse parallel with the fourth resistor. The anode of the diode and the common end of the fourth resistor are used to connect the PWM signal, and the common end of the fourth resistor and the fifth resistor is connected with the gate of the MOSFET and one end of the third resistor, respectively.

3. A precision pulsed constant current device for electrochemical surface treatment of materials on the micrometer scale according to claim 2, characterized in that: The other end of the third resistor is connected to the ground.

4. A precision pulsed constant current device for electrochemical surface treatment of materials on the micrometer scale according to claim 2, characterized in that: The control pin of the constant current source chip includes a SET pin and an OUT pin, and the voltage dividing network includes a second resistor, a seventh resistor and an adjustable resistor. The seventh resistor and the adjustable resistor are connected in series, one end of the seventh resistor is connected with the SET pin of the constant current source chip, one end of the adjustable resistor is connected with the drain of the MOSFET after being connected with one end of the second resistor, and the other end of the second resistor is connected with the OUT pin of the constant current source chip. The control system (4) determines the current value of the workpiece (3) to be processed according to the voltage signal between the sampling resistors. The control system (4) compares the current value of the workpiece (3) to be processed with the preset constant current value, increases the resistance value of the adjustable resistor if the current value is greater than the preset constant current value, and decreases the resistance value of the adjustable resistor if the current value is less than the preset constant current value, so as to realize the constant current control of the workpiece (3) to be processed. The control system (4) is used to detect the voltage of the workpiece (3) to be processed, and issue a stop electrochemical operation control instruction if the voltage drop amplitude exceeds X% or the voltage abnormally rises within a set time. The set time is 2-5 sampling periods, and X% is 10%-60%. The voltage abnormally rising refers to that the voltage rising amplitude exceeds 40% within N sampling periods, and N is 3-8. The current range of the constant current control is 50-200 mA.

5. A precision pulsed constant current device for electrochemical surface treatment of materials on the micrometer scale according to claim 1, characterized in that: The process of the control system (4) controlling the power supply system (1) to perform electrochemical operation on the workpiece (3) in the electrolyte system (2) is as follows: the control system (4) issues a heating control instruction, when the heating system heats the electrolyte to the set temperature, the control system (4) issues a PWM signal, and when the running time reaches the set value after the PWM signal is issued, the control system (4) issues a stop electrochemical operation control instruction, so as to complete the electrochemical operation on the workpiece (3).

6. A precision pulsed constant current device for microscale electrochemical surface treatment of materials as claimed in claim 5, wherein: The control system (4) is used for: detecting the electrolyte temperature data, when the electrolyte temperature is lower than the set temperature by 3℃, controlling the electrolyte heating system (5) to increase the heating power; when the electrolyte temperature is higher than the set temperature by 3℃, controlling the electrolyte heating system (5) to reduce the heating power; when the temperature deviates from the set temperature by ±5℃, controlling the electrolyte heating system (5) to stop working.

7. A precision pulsed constant current device for microscale electrochemical surface treatment of materials as claimed in claim 1, wherein: The control system (4) comprises a PLC (8) and a pulse generation control circuit (9), and the pulse generation control circuit (9) is used for generating a PWM signal.

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