Electrical discharge machining discharge plasma regulation circuit and method

Abstract

The application discloses an electric spark machining discharge plasma regulation circuit and method, and relates to the technical field of electric spark discharge machining. In the circuit, a core control unit is used to control the conduction of different loops of MOS tubes of each resistance current-limiting loop to generate oscillation currents with different amplitudes in the process of long-pulse-width machining. scc The core control unit is used to generate a peak current superimposed on a rectangular current in the process of short-pulse-width machining, and control the conduction of MOS tubes Q scd off to make the peak capacitor C sc charged to a peak voltage value; whenever the discharge pulse ends and the basic rectangular discharge current drops to 0, the control MOS tube Q scc off, the MOS tube Q scd is turned on to make the peak capacitor C sc discharge to generate a peak current. The application can realize the targeted regulation of the discharge plasma, thereby greatly promoting the throwing of molten metal, improving the discharge machining efficiency and reducing the thickness of a recast layer.

Description

Technical Field

[0001] The present application relates to the technical field of electric spark discharge machining, and in particular to an electric spark machining discharge plasma control circuit and method. Background Art

[0002] Electrospark machining (EDM) technology is a special machining method that utilizes pulsed spark discharges between a tool electrode immersed in a working fluid and a workpiece. The high temperature of the discharge plasma melts and vaporizes the workpiece material in the local area of ​​the discharge point, and then copies the electrode shape onto the workpiece. Due to its unique material removal mechanism and typical non-contact machining method, it has some advantages that are difficult to achieve with traditional cutting machining, such as "using softness to overcome hardness", "striking objects through the air", and "meticulous". At present, EDM technology has become an indispensable part of advanced manufacturing technology, playing an irreplaceable role in solving difficult-to-cut materials, complex shapes, precision and micro-machining problems, especially in the aerospace, automotive, energy, microelectronics and other manufacturing fields.

[0003] Currently, the main factor hindering the further development of EDM technology is its low molten material ejection rate. This refers to the low molten material ejection rate. This is because when the plasma's thermal energy acts on the workpiece surface, melting the workpiece material, not all of the molten material is effectively ejected. Instead, over 70% of the molten material remains on the workpiece surface and resolidifies upon cooling. This phenomenon primarily results in low energy utilization and machining efficiency, as only a small portion of the energy applied to the discharge plasma by the pulsed power supply actually results in material removal. Furthermore, after cooling, the molten material resolidifies on the workpiece surface, forming a recast layer. This recast layer has significantly different physical and chemical properties from the workpiece's base material and is highly likely to contain defects such as microcracks, which can negatively impact the serviceability of the machined part. Therefore, the industry urgently needs a method to significantly enhance the ejection of molten material during the discharge process. Controlling the heat and pressure sources of the discharge plasma itself is a fundamental measure to enhance molten material ejection and improve EDM performance. However, achieving targeted control of the discharge plasma remains a pressing technical challenge. Summary of the Invention

[0004] The purpose of this application is to provide an EDM discharge plasma control circuit and method, which can achieve targeted control of the discharge plasma, promote the ejection of molten material during the discharge process, thereby improving processing efficiency and reducing the thickness of the recast layer.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides an EDM discharge plasma control circuit, the EDM discharge plasma control circuit comprising: a core control unit, a spike generation circuit, and an oscillation current circuit;

[0007] The core control unit is connected to the peak generating circuit and the oscillating current circuit respectively;

[0008] The peak generating circuit includes: a peak capacitor C sc 、MOS tube Q scc And MOS tube Q scd ; Peak capacitance C sc With MOS tube Q scc After being connected in series, they are connected in parallel to both ends of the DC power supply; the peak capacitor C sc With MOS tube Q scd After being connected in series, they are connected in parallel to both ends of the discharge gap; the spike generating circuit is used to generate a current spike in the discharge process;

[0009] The oscillating current loop includes: four identical resistance current limiting loops; each resistance current limiting loop includes: a MOS tube and a resistor connected in series; the four loops are connected in parallel to both ends of the discharge gap;

[0010] The core control unit is used to control the MOS tube of each resistance current limiting loop to conduct different loops during the long pulse width processing process, generating oscillating currents with different oscillation starting times and amplitudes; the core control unit is also used to control the generation of current spikes during the short pulse width processing process, which controls the MOS tube Q during the pulse duration. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever the discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current.

[0011] Optionally, the core control unit is an FPGA control unit.

[0012] Optionally, the EDM discharge plasma control circuit further includes: an auxiliary breakdown circuit; the auxiliary breakdown circuit is connected to the core control unit;

[0013] The auxiliary breakdown circuit is used to conduct the circuit under the control of the core control unit, generate high voltage at both ends of the discharge gap before discharge begins, and close the circuit under the control of the core control unit after discharge breakdown occurs.

[0014] Optionally, the auxiliary breakdown circuit includes: a MOS tube Qhv and resistor R hv .

[0015] Optionally, the peak generating circuit further includes: scc The series charging resistor R scc .

[0016] In a second aspect, the present application provides an EDM discharge plasma control method, which is implemented using the EDM discharge plasma control circuit. The EDM discharge plasma control method includes:

[0017] Before starting processing, determine the control parameters; the control parameters include: oscillation start time, oscillation current amplitude, oscillation period and peak current peak value;

[0018] During the processing, the long pulse width processing step is first started to control the MOS tubes of each resistor current limiting loop of the oscillation current loop to conduct different loops, generating oscillation currents with different oscillation starting times, oscillation periods and amplitudes;

[0019] When the long pulse width machining process reaches the specified time or depth, the short pulse width machining process is started for continuous discharge machining. During the duration of each discharge pulse, the MOS tube Q in the spike generation circuit is controlled. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever a single discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current;

[0020] After completing the processing, cut off the pulse power supply and the processing is completed.

[0021] Optionally, determining the control parameters specifically includes:

[0022] Conduct thermal-flux coupling simulation and trial processing on the workpiece material to determine the control parameters.

[0023] Optionally, the starting long pulse width processing step of controlling the MOS tube of each resistor current limiting loop of the oscillating current loop to conduct different loops to generate oscillating currents of different amplitudes specifically includes:

[0024] At the beginning of the process, the MOS tube Q in the auxiliary breakdown circuit is controlled first. hv Conducting, high voltage is generated across the discharge gap;

[0025] When the discharge breakdown is detected, the MOS tube Q in the auxiliary breakdown circuit is controlled.hv Turn off; control the four resistor current limiting circuits in the oscillating current loop to be turned on, inject energy into the discharge plasma with a constant maximum current, and start timing at the same time;

[0026] When the timing reaches the oscillation start time, the three-way resistor current limiting loop remains on, controlling the other resistor current limiting loop to start periodically turning on and off according to the oscillation cycle, causing the discharge current to oscillate and continue timing;

[0027] When the timing reaches the set pulse width, all four resistor current limiting circuits are turned off, the current discharge pulse ends, and the pulse pause phase begins.

[0028] When the timing reaches the set pulse pause time, the MOS tube Q in the control auxiliary breakdown loop is returned to hv The process of conducting and generating high voltage at both ends of the discharge gap continues until the processing is completed.

[0029] Optionally, when the long pulse width processing step is processed to a specified time or depth, the short pulse width processing step is started to control the MOS tube Q in the spike generation circuit during each discharge pulse duration. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever the discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc The discharge generates a peak current, specifically including:

[0030] At the beginning of the process, the MOS tube Q in the auxiliary breakdown circuit is controlled first. hv Conducting, high voltage is generated across the discharge gap;

[0031] When the discharge breakdown is detected, the MOS tube Q in the auxiliary breakdown circuit is controlled. hv Shut down and control one or more of the four resistor current limiting circuits to be turned on at the same time, generating a basic rectangular discharge current and starting timing at the same time;

[0032] While the basic rectangular discharge current is generated, the MOS tube Q is controlled scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge;

[0033] When the timing reaches the set pulse width, all the conducting MOS tubes in the four-way resistor current limiting loop are turned off at the same time, and the basic rectangular discharge current begins to decrease;

[0034] When the basic rectangular discharge current drops to 0, the MOS tube Q scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Rapid discharge generates peak current;

[0035] When the peak capacitance C sc After the discharge is completed, the MOS tube Q scc Shut down, causing all discharge currents to drop rapidly, the current discharge pulse ends, and enters the pulse pause phase;

[0036] When the timing reaches the set pulse pause time, the MOS tube Q in the control auxiliary breakdown loop is returned to hv The process of conducting and generating high voltage at both ends of the discharge gap continues until the processing is completed.

[0037] According to the specific embodiments provided in this application, this application has the following technical effects:

[0038] The present application provides a discharge plasma control circuit and method for electrospark machining. During long-pulse-width machining, a core control unit is used to control an oscillating current loop to change the traditional rectangular discharge pulse into a post-process oscillating pulse. The discharge current of the post-process oscillating pulse remains constant at the initial stage of discharge to ensure sufficient melting of the workpiece material, and periodically rises and falls with a specific oscillation period after the oscillation starts, thereby strengthening the expansion and contraction movement of the discharge plasma to promote the ejection of molten metal. During short-pulse-width machining, the core control unit is used to control the spike generation loop to apply a rapidly rising spike current at the current tailing stage of the traditional rectangular discharge pulse, causing the discharge plasma, which has already contracted and is about to collapse, to expand violently again, thereby promoting the explosive ejection of molten metal. The present application controls the discharge plasma through post-process oscillating pulses and spike pulses, replacing the traditional rectangular wave pulse with a discharge pulse of a special waveform, to achieve targeted control of the discharge plasma, thereby solving the problem of low molten material ejection rate in existing electrospark machining processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 This is a schematic diagram of a structure of an EDM discharge plasma control circuit in one embodiment of the present application;

[0041] Figure 2 This is a current waveform diagram of the post-process oscillation control proposed in an embodiment of the present application;

[0042] Figure 3 This is a current waveform diagram of the spike pulse control proposed in one embodiment of the present application;

[0043] Figure 4 A comparison chart of material removal rates between processing with spike pulse control and processing with traditional rectangular pulses;

[0044] Figure 5 This is a comparison chart of material removal rates between machining using post-process oscillation control and machining using traditional rectangular pulses;

[0045] Figure 6 This is a comparison of the thickness of the recast layer on the workpiece surface after processing using post-process oscillation control and using traditional rectangular pulse processing. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0048] In an exemplary embodiment, Figure 1 As shown, the present application provides an EDM discharge plasma control circuit, which includes: a core control unit, a spike generation circuit, and an oscillation current circuit;

[0049] The core control unit is connected to the peak generating circuit and the oscillating current circuit respectively;

[0050] The peak generating circuit includes: a peak capacitor C sc 、MOS tube Q scc And MOS tube Q scd ; Peak capacitance C sc With MOS tube Q scc After being connected in series, they are connected in parallel to both ends of the DC power supply; the peak capacitor C sc With MOS tube Q scdAfter being connected in series, they are connected in parallel to both ends of the discharge gap; the spike generating circuit is a capacitor circuit with controllable charging and discharging superimposed on the resistor current limiting circuit. When the resistor current limiting circuit is turned on and the discharge continues, the capacitor charging circuit is turned on at the same time, and the capacitor voltage is charged to the peak voltage value; when the resistor current limiting circuit is turned off and the discharge pulse ends, due to the parasitic inductance in the overall discharge circuit, the discharge current does not drop to 0 instantly, but gradually decreases in the form of a tail. At this time, at the appropriate moment in the tailing stage of the discharge current, the capacitor discharge circuit is controlled to be turned on, and the energy stored in the capacitor is quickly applied to the discharge gap, thereby generating a rapidly rising current spike. Among them, the greater the degree of contraction of the discharge plasma, the more significant the explosive ejection effect caused by the spike current;

[0051] The oscillating current loop includes: four identical resistor current limiting loops; each resistor current limiting loop includes: a MOS tube (Q bc1 To Q bc4 ) and resistance (R bc1 to R bc4 ); the four identical resistor current-limiting circuits are four parallel, on-off controllable resistor current-limiting circuits. At the beginning of discharge, the four circuits are simultaneously turned on and working, at which time the discharge current is constantly at its maximum value; and after the oscillation starts, one to three of the four circuits begin to periodically turn off and on according to the oscillation cycle, thereby causing the discharge current to periodically decrease and increase, producing an oscillating effect.

[0052] The core control unit is used to control the MOS tube of each resistance current limiting loop to conduct different loops during the long pulse width processing process to generate oscillating currents of different amplitudes; the core control unit is also used to control the MOS tube Q during the pulse duration during the short pulse width processing process. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; when the discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current.

[0053] The core control unit is an FPGA control unit.

[0054] In order to assist the discharge breakdown and realize accurate discharge and regulation timing control, the EDM discharge plasma regulation circuit further comprises: an auxiliary breakdown circuit; the auxiliary breakdown circuit is connected to the core control unit;

[0055] The auxiliary breakdown circuit includes: a MOS tube Q hv and resistor R hvThe auxiliary breakdown circuit is used to conduct the circuit under the control of the core control unit, generating a high voltage across the discharge gap. When a discharge breakdown occurs, the circuit is closed under the control of the core control unit. The post-process oscillation control implementation circuit or the peak control implementation circuit begins to operate according to the established control timing.

[0056] The peak generating circuit also includes: scc The series charging resistor R scc .

[0057] The present application can significantly promote the ejection of molten metal during electrospark discharge machining through the post-process oscillation control method and the peak pulse control method, thereby improving the overall machining efficiency by more than 25% and reducing the thickness of the recast layer by about 56%; the present application is to promote the ejection of molten metal, and it itself does not cause the melting of new workpiece metal, so the surface quality of the machining workpiece after the control method is adopted will not be significantly affected; the present application can be achieved by optimizing the pulse power supply and its control strategy, without the need to modify the machine tool body structure, and is relatively easy to implement.

[0058] Based on the same inventive concept, embodiments of the present application also provide an EDM discharge plasma control method for implementing the aforementioned EDM discharge plasma control circuit. The solution provided by this method is similar to the solution described in the aforementioned method. Therefore, the specific limitations in one or more of the following embodiments of the EDM discharge plasma control method can be found in the above-mentioned limitations on the EDM discharge plasma control circuit and will not be further elaborated here.

[0059] like Figure 2 As shown, the post-process oscillation pulse control proposed in this application is specifically manifested in the use of a pulse discharge current that "first remains constant and then starts periodic oscillation", wherein the oscillation start moment is the dividing point between the current remaining constant and the periodic oscillation.

[0060] like Figure 3 As shown, the spike pulse control method proposed in this application specifically refers to applying a rapidly rising spike current when the resistor current limiting loop is turned off and the basic rectangular current almost drops to 0. The spike current does not exist at the same time as the basic rectangular current in the stable stage.

[0061] In an exemplary embodiment, a method for controlling discharge plasma in electrospark machining is provided, comprising:

[0062] S1, determining control parameters before processing; the control parameters include: oscillation start time, oscillation current amplitude, oscillation period and peak current peak value;

[0063] S1 specifically includes:

[0064] Conduct thermal-flux coupling simulation and trial processing on the workpiece material to determine the control parameters.

[0065] S2, during the processing, first starts the long pulse width processing step, controlling the MOS tubes of each resistor current limiting loop in the oscillation current loop to conduct different loops, generating oscillation currents with different oscillation starting times, oscillation periods and amplitudes;

[0066] S2 specifically includes:

[0067] S21, when the processing starts, first control the MOS tube Q in the auxiliary breakdown circuit hv Conducting, high voltage is generated across the discharge gap;

[0068] S22, when the discharge breakdown is detected, controls the MOS tube Q in the auxiliary breakdown circuit hv Turn off; control the four resistor current limiting circuits in the oscillating current loop to be turned on, inject energy into the discharge plasma with a constant maximum current, and start timing at the same time;

[0069] S23, when the timing reaches the oscillation start time, the three-way resistor current limiting loop remains on, and the other resistor current limiting loop is controlled to start periodically turning on and off according to the oscillation period, causing the discharge current to oscillate, and the timing continues;

[0070] S24, when the timing reaches the set pulse width, all four resistor current limiting circuits are turned off, the current discharge pulse ends, and the pulse pause phase begins;

[0071] S25, when the timing reaches the set pulse pause time, repeat steps S21-S24 until the processing is completed.

[0072] S3, when the long pulse width processing step is processed to the specified time or depth, the short pulse width processing step is started, and the MOS tube Q in the spike generation circuit is controlled during the duration of each discharge pulse. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever the discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current;

[0073] S3 specifically includes:

[0074] S31, when the processing starts, first control the MOS tube Q in the auxiliary breakdown circuit hv Conducting, high voltage is generated across the discharge gap;

[0075] S32, when the discharge breakdown is detected, controls the MOS tube Q in the auxiliary breakdown circuit hv Shut down and control one or more of the four resistor current limiting circuits to be turned on at the same time, generating a basic rectangular discharge current and starting timing at the same time;

[0076] S33, while the basic rectangular discharge current is generated, controls the MOS tube Q scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge;

[0077] S34, when the timing reaches the set pulse width, all the conducting MOS tubes in the four-way resistor current limiting loop are turned off at the same time, and the basic rectangular discharge current begins to decrease;

[0078] S35, when the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Rapid discharge generates peak current;

[0079] S36, when the peak capacitance C sc After the discharge is completed, the MOS tube Q scc Shut down, causing all discharge currents to drop rapidly, the current discharge pulse ends, and enters the pulse pause phase;

[0080] S37, when the timing reaches the set pulse pause time, repeat steps S31-S36 until the processing is completed.

[0081] S4, after the processing is completed, the pulse power is cut off and the processing is completed.

[0082] This application can implement the discharge plasma control process only by controlling the pulse power supply, without the need for major modifications to the machine tool body; the discharge machining process is essentially optimized through the post-process oscillation pulse control of the long pulse width machining process and the spike pulse control of the short pulse width machining process; this application regulates the discharge plasma characteristics, the essential factor that affects the discharge machining process, by proposing post-process oscillation pulses and spike pulses, thereby fundamentally promoting the ejection of molten metal during the discharge process. Figure 4-Figure 6 As shown, by adopting the method provided in this application, the overall processing efficiency can be improved by more than 25%, and the thickness of the recast layer can be reduced by about 56%.

[0083] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An electrospark machining plasma control circuit, characterized in that: include: Core control unit, spike generation circuit and oscillation current circuit; The core control unit is connected to the peak generating circuit and the oscillating current circuit respectively; The peak generating circuit includes: a peak capacitor C sc 、MOS tube Q scc And MOS tube Q scd ; Peak capacitance C sc With MOS tube Q scc After being connected in series, they are connected in parallel to both ends of the DC power supply; the peak capacitor C sc With MOS tube Q scd After being connected in series, they are connected in parallel to both ends of the discharge gap; the spike generating circuit is used to generate a current spike in the discharge process; The oscillating current loop includes: four identical resistance current limiting loops; each resistance current limiting loop includes: a MOS tube and a resistor connected in series; the four loops are connected in parallel to both ends of the discharge gap; The core control unit is used to control the MOS tube of each resistance current limiting loop to conduct different loops during the long pulse width processing process, generating oscillating currents with different oscillation starting times and amplitudes; the core control unit is also used to control the generation of current spikes during the short pulse width processing process, and control the MOS tube Q during the pulse duration. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever the discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current.

2. The EDM discharge plasma control circuit according to claim 1, characterized in that: The core control unit is an FPGA control unit.

3. The EDM discharge plasma control circuit according to claim 2, characterized in that: Also includes: Auxiliary breakdown circuit; the auxiliary breakdown circuit is connected to the core control unit; The auxiliary breakdown circuit is used to conduct the circuit under the control of the core control unit to generate high voltage at both ends of the discharge gap, and to close the circuit under the control of the core control unit when discharge breakdown occurs.

4. The EDM discharge plasma control circuit according to claim 3, characterized in that: The auxiliary breakdown circuit includes: a MOS tube Q hv and resistor R hv .

5. The EDM discharge plasma control circuit according to claim 4, characterized in that: The peak generating circuit also includes: scc The charging resistor R in series scc .

6. A method for controlling discharge plasma in electric discharge machining, implemented by the electric discharge machining discharge plasma control circuit according to claim 5, characterized in that: The method for controlling discharge plasma in electrospark machining comprises: Determine the control parameters before processing; the control parameters include: oscillation start time, oscillation current amplitude, oscillation period and peak current peak value; During the processing, the long pulse width processing step is first started to control the MOS tube of each resistor current limiting loop in the oscillating current loop to conduct different loops, generating oscillating currents with different oscillation starting times, oscillation periods and amplitudes; When the long pulse width machining process reaches the specified time or depth, the short pulse width machining process is started for continuous discharge machining. During the duration of each discharge pulse, the MOS tube Q in the spike generation circuit is controlled. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever a single discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current; After completing the processing, cut off the pulse power supply and the processing is completed.

7. The method for controlling discharge plasma in electric spark machining according to claim 6, characterized in that: The determining of the control parameters specifically includes: Conduct thermal-flux coupling simulation and trial processing on the workpiece material to determine the control parameters.

8. The method for controlling discharge plasma in electric discharge machining according to claim 6, characterized in that: The long pulse width processing step is started, and during the processing, the MOS tube of each resistor current limiting loop in the oscillating current loop is controlled to conduct different loops to generate oscillating currents of different amplitudes, specifically including: At the beginning of the process, the MOS tube Q in the auxiliary breakdown circuit is controlled first. hv Conducting, high voltage is generated across the discharge gap; When the discharge breakdown is detected, the MOS tube Q in the auxiliary breakdown circuit is controlled. hv Turn off; control the four resistor current limiting circuits in the oscillating current loop to be turned on, inject energy into the discharge plasma with a constant maximum current, and start timing at the same time; When the timing reaches the oscillation start time, the three-way resistor current limiting loop remains on, controlling the other resistor current limiting loop to start periodically turning on and off according to the oscillation cycle, causing the discharge current to oscillate and continue timing; When the timing reaches the set pulse width, all four resistor current limiting circuits are turned off, the current discharge pulse ends, and the pulse pause phase begins. When the timing reaches the set pulse pause time, the MOS tube Q in the control auxiliary breakdown loop is returned to hv The process of conducting and generating high voltage at both ends of the discharge gap continues until the processing is completed.

9. The method for controlling discharge plasma in electric discharge machining according to claim 6, characterized in that: When the long pulse width processing step is processed to a specified time or depth, the short pulse width processing step is started, and the MOS tube Q in the peak generation circuit is controlled during the duration of each discharge pulse. scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge to the peak voltage value; whenever the discharge pulse ends and the basic rectangular discharge current drops to 0, the MOS tube Q is controlled scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Discharge generates peak current, including: At the beginning of the process, the MOS tube Q in the auxiliary breakdown circuit is controlled first. hv Conducting, high voltage is generated across the discharge gap; When the discharge breakdown is detected, the MOS tube Q in the auxiliary breakdown circuit is controlled. hv Shut down and control one or more of the four resistor current limiting circuits to be turned on at the same time, generating a basic rectangular discharge current and starting timing at the same time; While the basic rectangular discharge current is generated, the MOS tube Q is controlled scc Conductivity, MOS tube Q scd Turn off, so that the peak capacitor C sc Charge; When the timing reaches the set pulse width, all the conducting MOS tubes in the four-way resistor current limiting loop are turned off at the same time, and the basic rectangular discharge current begins to decrease; When the basic rectangular discharge current drops to 0, the MOS tube Q scc Shutdown, MOS tube Q scd Turn on, so that the peak capacitor C sc Rapid discharge generates peak current; When the peak capacitance C sc After the discharge is completed, the MOS tube Q scc Shut down, causing all discharge currents to drop rapidly, the current discharge pulse ends, and enters the pulse pause phase; When the timing reaches the set pulse pause time, the MOS tube Q in the control auxiliary breakdown loop is returned to hv The process of conducting and generating high voltage at both ends of the discharge gap continues until the processing is completed.

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