A micro-hole electrospark machining method and system with online electrode trimming

Abstract

A micro-hole EDM method and system with online electrode trimming is described. During the machining process of a workpiece by a tool electrode, the tool electrode performs machining in multiple continuous cycles. Each cycle consists of a normal forward machining period and a reverse trimming period. The normal forward machining period consists of multiple positive pulses. During the normal forward machining period, a positive pulse voltage is applied to the workpiece and the tool electrode, directed from the workpiece toward the tool electrode, causing electrical discharge machining (EDM) on the workpiece. The reverse trimming period consists of multiple reverse pulses. During the reverse trimming period, a reverse pulse voltage is applied to the tool electrode and the workpiece, directed from the tool electrode toward the workpiece, causing electrical discharge trimming of the tool electrode. A control module switches between the positive and reverse pulse voltages. This solution can improve the efficiency, quality, and consistency of micro-hole EDM.

Description

Technical Field

[0001] The present invention relates to the technical field of electric spark machining, and in particular to a method and system for electric spark machining of micro holes with online electrode trimming. Background Art

[0002] CNC EDM micro-hole machining is a type of industrial processing equipment that uses a conductive hollow electrode tube or fine electrode wire as a machining tool electrode to perform pulsed spark discharge on the workpiece to erode the workpiece metal material and achieve the machining of micro-holes. It is usually used to machine precision micro-holes in super-hard steel, cemented carbide, high-temperature alloy and any conductive material, especially difficult-to-machine materials.

[0003] After continuous discharge machining, the tool electrode will wear out at the end of the electrode, and due to uneven wear, the electrode end will change from a normal flat shape to a pointed shape, resulting in uneven discharge energy and carbon deposition. During the continuous discharge machining process, the workpiece machining will become unstable, the machining accuracy will be reduced, the dimensional error will increase, the defective rate of the workpiece will increase, and the production cost will also increase.

[0004] The traditional method of trimming tool electrodes is to move the electrode to the corresponding position after completing a small hole machining and before machining the next small hole, and trim the electrode by swapping the polarity of the workpiece end and the electrode end, such as by swapping the polarity through an external switching method such as a relay, thereby etching the electrode end to restore the electrode end to a flat shape.

[0005] However, this traditional repair method requires that the electrode be removed for trimming after the current hole is machined, and the next hole can be machined after the trimming is completed, resulting in poor consistency in the machined holes. At the same time, under this traditional repair method, the EDM small hole machine needs to trim the electrode after a small hole is machined, and it is impossible to pause for trimming during the continuous machining of a small hole. During a continuous machining process, the end of the electrode will gradually wear out, resulting in a gradual deterioration in the machining state. Therefore, this traditional repair method can only improve the machining condition at the entrance of the hole. As the machining progresses, the damage to the electrode cannot be effectively controlled, affecting the machining stability, especially the machining stability at the hole exit, and thus affecting the machining quality of the workpiece hole.

[0006] To address the above problems, it is necessary to provide a micro-hole EDM solution with online electrode trimming to improve machining efficiency and quality, ensure machining process stability and achieve high-efficiency machining. Summary of the Invention

[0007] The object of the present invention is to provide a micro-hole electrospark machining method and system for online electrode trimming.

[0008] The technical solution adopted in the present invention is:

[0009] A micro-hole electrospark machining method with online electrode trimming.

[0010] During the machining process of a workpiece by the tool electrode, the workpiece is machined in a plurality of continuous cycle machining periods, each cycle comprising a forward normal machining period and a reverse trimming machining period;

[0011] The forward normal machining period is composed of a plurality of forward pulses; during the forward normal machining period, a forward pulse voltage is applied to the workpiece to be machined and the tool electrode, and the forward pulse voltage is directed from the workpiece to be machined toward the tool electrode, thereby performing electrical discharge machining on the workpiece to be machined;

[0012] The reverse trimming processing period is composed of a plurality of reverse pulses; in the reverse trimming processing period, a reverse pulse voltage is applied to the tool electrode and the workpiece to be processed, and the reverse pulse voltage is directed from the tool electrode to the workpiece to be processed, so as to perform discharge trimming on the tool electrode;

[0013] The forward pulse voltage and the reverse pulse voltage are switched by a control module.

[0014] A further technical solution is that in each of the cyclic processing cycles, a delay protection period is provided between the forward normal processing period and the reverse trimming processing period; in the delay protection period, the voltage between the tool electrode and the workpiece to be processed is zero; the length of the delay protection period is 10 to 50 microseconds.

[0015] A further technical solution has an advance trimming mechanism, including the following contents;

[0016] During the forward normal processing period, a peak value of a transient pulse voltage of a discharge breakdown is detected in each forward pulse. When the peak value of the transient pulse voltage is greater than or equal to a preset voltage threshold, the forward pulse is determined to be a valid pulse; otherwise, the forward pulse is determined to be a defective pulse.

[0017] For each of the forward normal processing periods, starting from the nth forward pulse therein, after each forward pulse ends, a total of n consecutive forward pulses from the forward pulse to the previous forward pulse are used as a detection range for judgment, wherein n is a preset natural number less than the total number of forward pulses in the forward normal processing period; the ratio of the number of defective pulses in the detection range to the total number of pulses is defined as a defect rate, and the control module determines whether the defect rate in the detection range is greater than or equal to a preset defect threshold value. If so, the current forward pulse voltage is switched to a reverse pulse voltage to enter an adaptive reverse trimming period; otherwise, the operation continues according to the normal process;

[0018] The adaptive reverse trimming period is composed of a plurality of reverse pulses. During the adaptive reverse trimming period, a reverse pulse voltage is applied to the tool electrode and the workpiece to be machined. The reverse pulse voltage is directed from the tool electrode toward the workpiece to perform discharge trimming on the tool electrode. The duration of the adaptive reverse trimming period is positively correlated with the value of the preset defect threshold.

[0019] After the adaptive reverse trimming period ends, the forward normal processing period begins.

[0020] According to a further technical solution, the preset voltage threshold is 40V.

[0021] According to a further technical solution, the range of the preset bad threshold is 10% to 30%; when the preset bad threshold is set to 10%, the duration of the adaptive reverse trimming period is set to 200 milliseconds. On this basis, for every 1% increase in the set value of the preset bad threshold, the set duration of the adaptive reverse trimming period is extended by 10%.

[0022] A further technical solution has a pre-penetration trimming mechanism, including the following contents;

[0023] During the drilling process of the workpiece to be machined by the tool electrode, the depth of the hole is called the total penetration depth, and the control module obtains the real-time drilling depth according to the feed distance of the tool electrode;

[0024] The ratio of the real-time depth to the total penetration depth is the penetration progress. When the penetration progress reaches a penetration threshold, the control module switches the current forward pulse voltage to a reverse pulse voltage to enter the reverse trimming processing period in advance.

[0025] According to a further technical solution, the penetration threshold is 80% to 98%.

[0026] According to a further technical solution, the time length of one of the cyclic processing cycles is 100 ms to 1 minute.

[0027] According to a further technical solution, the reverse trimming processing period accounts for less than or equal to 10% of the duration of the cyclic processing period.

[0028] The beneficial effect of this solution is that: the machining process of the tool electrode on the workpiece to be machined is divided into a forward normal machining period and a reverse trimming machining period, and the switching between the two is achieved by automatically switching the forward pulse voltage and the reverse pulse voltage on the tool electrode and the workpiece to be machined, wherein the device is in a normal machining state for the workpiece to be machined during the forward normal machining period, and the device is in a trimming state for the tool electrode during the reverse trimming machining period, and cyclic machining is performed with these two periods as a cyclic machining cycle, so that the tool electrode can be trimmed during the continuous machining process, thereby ensuring the consistency of the machined hole;

[0029] At the same time, since the equipment switches between the normal processing state and the dressing state in a short period of time, the tool electrode will be dressed after a short processing time when the wear is not serious, thus ensuring the original state of the tool electrode and ensuring the processing stability of the entire process from the hole entrance to the hole exit during the hole processing, thereby improving the processing quality.

[0030] as well as:

[0031] A micro-hole EDM system with online electrode trimming.

[0032] including a discharge circuit and a control module;

[0033] The discharge circuit includes a pulse power supply, a processing polarity switching working circuit, a protection switch and a current limiting resistor arranged in series, and the pulse power supply outputs a pulse voltage with an amplitude in the range of 50V to 180V;

[0034] The machining polarity switching working circuit includes a first branch and a second branch connected in parallel, wherein the first branch is provided with a first switch and a third switch connected in series, and the second branch is provided with a second switch and a fourth switch connected in series; an electrode port for supplying power to a tool electrode is provided between the first switch and the third switch, and a workpiece port for supplying power to a workpiece to be machined is provided between the second switch and the fourth switch;

[0035] The control module controls the opening and closing of the first switch, the second switch, the third switch, and the fourth switch;

[0036] When the first switch and the fourth switch are closed, and the second switch and the third switch are open, the electrode port is connected to the positive pole of the pulse power supply, and the workpiece port is connected to the negative pole of the pulse power supply; when the first switch and the fourth switch are open, and the second switch and the third switch are closed, the electrode port is connected to the negative pole of the pulse power supply, and the workpiece port is connected to the positive pole of the pulse power supply.

[0037] The beneficial effect of this solution is that: when the system is working, the control module switches on and off each switch, which can change the positive and negative polarity of the electrode port and the workpiece port, thereby switching the tool electrode and the workpiece to be processed between the states of being subjected to forward pulse voltage and reverse pulse voltage; when the workpiece to be processed and the tool electrode are in the forward pulse voltage state, the equipment is in the normal processing state of the workpiece to be processed, and when the tool electrode and the workpiece to be processed are in the reverse pulse voltage state, the equipment is in the trimming state of the tool electrode; thus, through this system, the equipment can be automatically switched between the normal processing state and the trimming state by the control module, without the need to move the tool electrode out for trimming, and the continuity of processing can be maintained when trimming the tool electrode, thereby improving processing efficiency; at the same time, through the cyclic switching between the normal processing state and the trimming state, the trimming quality of the tool electrode can be guaranteed, thereby improving the processing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Attachment Figure 1 This is a waveform diagram of a cyclic processing cycle of an embodiment of the present invention;

[0039] Attachment Figure 2 Flowchart of the processing method in an embodiment of the present invention;

[0040] Attachment Figure 3 Schematic diagram of a circuit of a processing system in an embodiment of the present invention.

[0041] In the above figures: 1. Pulse power supply; 2. Machining polarity switching circuit; 3. Protection switch; 4. Current-limiting resistor; 51. First switch; 52. Second switch; 53. Third switch; 54. Fourth switch; 6. Electrode port; 7. Workpiece port; T. Machining cycle; T1. Forward normal machining period; T2. Reverse trimming period; T3. Adaptive reverse trimming period; T4. Delay protection period; t1. Forward pulse; t2. Reverse pulse. Implementation Method

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0043] The present invention will be clearly illustrated below with drawings and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art will be able to make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0044] The terms used herein are for describing specific embodiments only and are not intended to be limiting of the present invention. Singular forms such as "a," "the," "this," "this," and "the" as used herein also include plural forms.

[0045] The terms “first”, “second”, etc. used in this document do not specifically refer to an order or sequence, nor are they used to limit this case. They are only used to distinguish components or operations described with the same technical terms.

[0046] As used herein, “connected” or “positioned” may refer to two or more components or devices being in direct or indirect physical contact with each other, or may refer to two or more components or devices operating or moving with each other.

[0047] The terms “include”, “including”, “have”, etc. used in this document are open-ended terms, meaning including but not limited to.

[0048] Unless otherwise noted, the terms used herein generally have their ordinary meanings in the art, in the context of this application, and in the specific context. Certain terms used to describe this application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this application.

[0049] The terms "front", "back", "up", "down", "left", "right", etc. used in this article are all directional terms. In this case, they are only used to illustrate the positional relationship between the various structures, and are not used to limit the scope of protection of this case or the specific direction during actual implementation.

[0050] like Figure 1 、 Figure 2 As shown, a micro-hole electrospark machining method with online electrode trimming is provided, and the specific contents include the following:

[0051] During the process of machining a workpiece by the tool electrode, the workpiece is machined in a plurality of continuous cyclic machining periods T. Each of the cyclic machining periods T consists of a forward normal machining period T1 and a reverse trimming machining period T2.

[0052] Among them, the forward normal processing period T1 is composed of multiple forward pulses t1; in the forward normal processing period T1, a forward pulse voltage is applied to the workpiece to be processed and the tool electrode, and the forward pulse voltage is directed from the workpiece to be processed to the tool electrode, and the workpiece to be processed is subjected to discharge processing; the reverse trimming processing period T2 is composed of multiple reverse pulses t2; in the reverse trimming processing period T2, a reverse pulse voltage is applied to the tool electrode and the workpiece to be processed, and the reverse pulse voltage is directed from the tool electrode to the workpiece to be processed, and the tool electrode is subjected to discharge trimming.

[0053] The forward pulse voltage and the reverse pulse voltage are switched by a control module, thereby alternating and cyclically working in the order of forward normal processing period T1, reverse trimming processing period T2, and forward normal processing period T1 during the processing.

[0054] This processing method divides the processing process of the tool electrode on the workpiece to be processed into a forward normal processing period T1 and a reverse trimming processing period T2. The switching between the two is achieved by automatically switching the forward pulse voltage and the reverse pulse voltage on the tool electrode and the workpiece to be processed. In the forward normal processing period T1, the equipment is in a normal processing state of the workpiece to be processed, and in the reverse trimming processing period T2, the equipment is in a trimming state of the tool electrode. Cyclic processing is performed with these two periods as a cyclic processing cycle T, so that the tool electrode can be trimmed during the continuous processing process, thereby ensuring the processing efficiency.

[0055] At the same time, since the equipment switches between the normal processing state and the dressing state in a short period of time, the tool electrode will be dressed after a short processing time when the wear is not serious, thus ensuring the working state of the tool electrode and ensuring the processing stability of the entire process from the hole entrance to the hole exit during the hole processing, thereby improving the processing quality.

[0056] In this embodiment, the time length of a cyclic processing period T is 100ms to 1min. Within this range, it is not too long to affect the processing state of the tool electrode, nor too short to cause frequent circuit switching and affect the efficiency and quality of the processing hole of the workpiece to be processed.

[0057] The reverse trimming processing period T2 accounts for less than or equal to 10% of the duration of the cyclic processing period T, so that while a small amount of time is spent on trimming, most of the time is left for the forward normal processing period T1 to process the workpiece to be processed, thereby ensuring overall processing efficiency.

[0058] In this embodiment, the forward pulse t1 consists of a forward discharge pulse width and a forward pulse interval, and the reverse pulse t2 consists of a reverse discharge pulse width and a reverse pulse interval; the pulse lengths of the forward pulse t1 and the reverse pulse t2 are both less than or equal to 500 microseconds, which can meet basic processing requirements, and the smaller the pulse length, the better the processing effect; the forward pulse voltage and the reverse pulse voltage have the same pulse voltage amplitude, and the pulse voltage amplitude is selected in the range of 50V to 180V, preferably 90V, which can achieve better processing effects.

[0059] In this embodiment, in each of the cyclic processing periods T, a delay protection period T4 is provided between the forward normal processing period T1 and the reverse trimming processing period T2 to protect the equipment; in the delay protection period T4, the voltage between the tool electrode and the workpiece to be processed is zero; the length of the delay protection period T4 is 10 to 50 microseconds.

[0060] In this method embodiment, there is also an advance trimming mechanism, including the following contents:

[0061] In the forward normal processing period T1, the instantaneous pulse voltage peak of the discharge breakdown is detected in each forward pulse t1. When the instantaneous pulse voltage peak is greater than or equal to a preset voltage threshold, the forward pulse t1 is determined to be a valid pulse, otherwise it is determined to be a bad pulse. In this embodiment, the preset voltage threshold is 40V.

[0062] For each of the forward normal processing time periods T1, starting from the nth forward pulse t1, after each forward pulse t1 ends, a total of n consecutive positive pulses t1 from the positive pulse t1 to the positive pulse t1 before the positive pulse t1 are used as the detection range for judgment, wherein n is a preset natural number that is smaller than the total number of positive pulses t1 in the forward normal processing time period T1; the ratio of the number of defective pulses in the detection range to the total number of pulses is defined as the defective rate, where the total number of pulses refers to the number of positive pulses t1 in the detection range, and the control module determines whether the defective rate of the detection range is greater than or equal to a preset defective threshold value. If so, the current forward pulse voltage is switched to the reverse pulse voltage to enter an adaptation reverse trimming time period T3; otherwise, work continues according to the normal process.

[0063] Among them, the adaptive reverse trimming period T3 is composed of multiple reverse pulses t2. In the adaptive reverse trimming period T3, a reverse pulse voltage is applied to the tool electrode and the workpiece to be processed. The reverse pulse voltage is directed from the tool electrode to the workpiece to be processed, and the tool electrode is discharged and trimmed; the duration of the adaptive reverse trimming period T3 is positively correlated with the size of the preset defective threshold; after the adaptive reverse trimming period T3 ends, the forward normal processing period T1 is entered.

[0064] Through this advance trimming mechanism, when the processing state is not good, it can be immediately switched to the trimming state without having to wait for the current forward normal processing period T1 to end before entering the reverse trimming processing period T2 for trimming, thereby ensuring the overall processing quality of the workpiece to be processed.

[0065] Specifically, the preset bad threshold value ranges from 10% to 30% and can be set within this range; when the preset bad threshold value is set to 10%, the duration of the adaptive reverse trimming period T3 is set to 200 milliseconds. On this basis, for every 1% increase in the set value of the preset bad threshold value, the set duration of the adaptive reverse trimming period T3 is extended by 10%; that is, the larger the preset bad threshold value, the longer the required trimming time, which is consistent with the actual situation.

[0066] In this method embodiment, there is also a pre-penetration trimming mechanism, including the following contents;

[0067] During the process of drilling the workpiece to be processed by the tool electrode, the depth of the hole is called the total penetration depth. The control module obtains the real-time depth of the hole through the feed distance of the tool electrode; the ratio of the real-time depth to the total penetration depth is the penetration progress. When the penetration progress reaches a penetration threshold, the control module switches the current forward pulse voltage to a reverse pulse voltage to enter the reverse finishing processing period T2 in advance.

[0068] The penetration threshold is 80% to 98%. In actual implementation, the operator can select and set it according to actual conditions, such as the depth of the hole to be drilled and other data.

[0069] Through this pre-penetration trimming mechanism, the tool electrode can be trimmed before penetrating the workpiece to be processed, so that it can be punched and penetrated in the best processing state to ensure the processing quality during penetration.

[0070] like Figure 3 As shown, a micro-hole EDM system with online electrode trimming is also provided, which is used to implement the above-mentioned micro-hole EDM method with online electrode trimming, including a discharge circuit and a control module.

[0071] The discharge circuit includes a pulse power supply 1, a processing polarity switching working circuit 2, a protection switch 3 and a current limiting resistor 4 arranged in series. The pulse power supply 1 outputs a pulse voltage with an amplitude in the range of 50V to 180V.

[0072] The machining polarity switching working circuit 2 includes a first branch and a second branch arranged in parallel, wherein a first switch 51 and a third switch 53 are provided in series on the first branch, and a second switch 52 and a fourth switch 54 are provided in series on the second branch; an electrode port 6 for supplying power to a tool electrode is provided between the first switch 51 and the third switch 53, and a workpiece port 7 for supplying power to a workpiece to be machined is provided between the second switch 52 and the fourth switch 54.

[0073] Under the design of the machining polarity switching working circuit 2, when the first switch 51 and the fourth switch 54 are closed, and the second switch 52 and the third switch 53 are open, the electrode port 6 is connected to the positive pole of the pulse power supply 1, and the workpiece port 7 is connected to the negative pole of the pulse power supply 1; in this state, the discharge circuit applies a reverse pulse voltage from the tool electrode to the workpiece to be machined, and the equipment is in a trimming state for the tool electrode.

[0074] When the first switch 51 and the fourth switch 54 are open, and the second switch 52 and the third switch 53 are closed, the electrode port 6 is connected to the negative pole of the pulse power supply 1, and the workpiece port 7 is connected to the positive pole of the pulse power supply 1; in this state, the discharge circuit applies a positive pulse voltage from the workpiece to be processed to the tool electrode to the tool electrode, and the equipment is in a normal processing state for the workpiece to be processed.

[0075] The control module (not shown in the figure) controls the opening and closing of the first switch 51, the second switch 52, the third switch 53 and the fourth switch 54, thereby automatically switching the opening and closing of each switch through the control module, and then switching the working state of the device; in this embodiment, the control module is a single-chip microcomputer, and the first switch 51, the second switch 52, the third switch 53, and the fourth switch 54 are all insulated gate bipolar transistor switches. The use of a single-chip microcomputer to control the opening and closing of the insulated gate bipolar transistor switches belongs to the prior art, and its specific structure and working principle are well known to those skilled in the art. It is not the invention of this case and is therefore not described in detail here.

[0076] When this processing system is working, the control module switches on and off each switch to change the positive and negative polarities of the electrode port 6 and the workpiece port 7, thereby switching the tool electrode and the workpiece to be processed between the states of being subjected to forward pulse voltage and reverse pulse voltage; when the workpiece to be processed and the tool electrode are in the forward pulse voltage state, the equipment is in the normal processing state of the workpiece to be processed, and when the tool electrode and the workpiece to be processed are in the reverse pulse voltage state, the equipment is in the trimming state of the tool electrode; thus, through this system, the equipment can be automatically switched between the normal processing state and the trimming state by the control module, without the need to move the tool electrode out for trimming, and the tool electrode can be trimmed online in real time during the processing process to maintain the consistency and continuity of the processed hole, thereby improving the processing efficiency; at the same time, through the cyclic switching between the normal processing state and the trimming state, the trimming quality of the tool electrode can be guaranteed, thereby improving the processing quality.

[0077] In actual implementation, the micro-hole EDM method can also be implemented by a machining system with other circuit structures having the same or similar functions, and is not limited to the machining system in this embodiment.

[0078] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A micro-hole electrospark machining method with online electrode trimming, characterized by: During the machining process of a workpiece by a tool electrode, machining is performed in a plurality of continuous cyclic machining periods (T), each of the cyclic machining periods (T) consisting of a forward normal machining period (T1) and a reverse trimming machining period (T2); The forward normal machining period (T1) is composed of a plurality of forward pulses (t1); in the forward normal machining period (T1), a forward pulse voltage is applied to the workpiece to be machined and the tool electrode, and the forward pulse voltage is directed from the workpiece to be machined to the tool electrode, thereby performing electrical discharge machining on the workpiece to be machined; The reverse trimming processing period (T2) is composed of a plurality of reverse pulses (t2); in the reverse trimming processing period (T2), a reverse pulse voltage is applied to the tool electrode and the workpiece to be processed, and the reverse pulse voltage is directed from the tool electrode to the workpiece to be processed, so as to perform discharge trimming on the tool electrode; The forward pulse voltage and the reverse pulse voltage are switched by a control module; In each of the cyclic processing periods (T), a delay protection period (T4) is provided between the forward normal processing period (T1) and the reverse trimming processing period (T2); during the delay protection period (T4), the voltage between the tool electrode and the workpiece to be processed is zero; and the length of the delay protection period (T4) is 10 to 50 microseconds.

2. The micro-hole electrospark machining method with online electrode trimming according to claim 1, characterized in that: It has an advance trimming mechanism, including the following contents; In the forward normal processing period (T1), a peak value of a transient pulse voltage of a discharge breakdown is detected in each forward pulse (t1); when the peak value of the transient pulse voltage is greater than or equal to a preset voltage threshold, the forward pulse (t1) is determined to be a valid pulse; otherwise, it is determined to be a bad pulse; For each of the forward normal processing time periods (T1), starting from the nth forward pulse (t1), after each forward pulse (t1) ends, a total of n consecutive forward pulses (t1) from the forward pulse (t1) to the number before the forward pulse (t1) are used as a detection range for judgment, wherein n is a preset natural number that is less than the total number of forward pulses (t1) in the forward normal processing time period (T1); the ratio of the number of defective pulses in the detection range to the total number of pulses is defined as a defect rate, and the control module determines whether the defect rate in the detection range is greater than or equal to a preset defect threshold value, and if so, switches the current forward pulse voltage to a reverse pulse voltage to enter an adaptive reverse trimming time period (T3); otherwise, continues to work according to the normal process; The adaptive reverse trimming period (T3) is composed of a plurality of reverse pulses (t2). In the adaptive reverse trimming period (T3), a reverse pulse voltage is applied to the tool electrode and the workpiece to be machined. The reverse pulse voltage is directed from the tool electrode to the workpiece to be machined, and discharge trimming is performed on the tool electrode. The duration of the adaptive reverse trimming period (T3) is positively correlated with the value of the preset bad threshold; After the adaptive reverse trimming period (T3) ends, the forward normal processing period (T1) is entered.

3. The micro-hole electrospark machining method with online electrode trimming according to claim 2, characterized in that: The preset voltage threshold is 40V.

4. The micro-hole electrospark machining method with online electrode trimming according to claim 2, characterized in that: The preset bad threshold ranges from 10% to 30%. When the preset bad threshold is set to 10%, the duration of the adaptive reverse trimming period (T3) is set to 200 milliseconds. On this basis, for every 1% increase in the set value of the preset bad threshold, the set duration of the adaptive reverse trimming period (T3) is extended by 10%.

5. The micro-hole electrospark machining method with online electrode trimming according to claim 1, characterized in that: It has a pre-penetration trimming mechanism, including the following: During the drilling process of the workpiece to be machined by the tool electrode, the depth of the hole is called the total penetration depth, and the control module obtains the real-time drilling depth according to the feed distance of the tool electrode; The ratio of the real-time depth to the total penetration depth is the penetration progress. When the penetration progress reaches a penetration threshold, the control module switches the current forward pulse voltage to a reverse pulse voltage to enter the reverse trimming processing period (T2) in advance.

6. The micro-hole electrospark machining method with online electrode trimming according to claim 5, characterized in that: The penetration threshold is 80% to 98%.

7. The micro-hole electrospark machining method with online electrode trimming according to claim 1, characterized in that: The time length of one of the cyclic processing periods (T) is 100 ms to 1 minute.

8. The micro-hole electrospark machining method with online electrode trimming according to claim 7, characterized in that: The reverse trimming processing period (T2) accounts for less than or equal to 10% of the duration of the cyclic processing period (T).

9. A micro-hole electrospark machining system with online electrode trimming, characterized by: Used to implement the processing method according to any one of claims 1 to 8; including a discharge circuit and a control module; The discharge circuit comprises a pulse power supply (1), a processing polarity switching working circuit (2), a protection switch (3) and a current limiting resistor (4) arranged in series, wherein the pulse power supply (1) outputs a pulse voltage with an amplitude within the range of 50V to 180V; The machining polarity switching working circuit (2) comprises a first branch and a second branch arranged in parallel, wherein a first switch (51) and a third switch (53) are provided in series on the first branch, and a second switch (52) and a fourth switch (54) are provided in series on the second branch; an electrode port (6) for supplying power to a tool electrode is provided between the first switch (51) and the third switch (53), and a workpiece port (7) for supplying power to a workpiece to be machined is provided between the second switch (52) and the fourth switch (54); The control module controls the opening and closing of the first switch (51), the second switch (52), the third switch (53) and the fourth switch (54); When the first switch (51) and the fourth switch (54) are closed, and the second switch (52) and the third switch (53) are open, the electrode port (6) is connected to the positive pole of the pulse power supply (1), and the workpiece port (7) is connected to the negative pole of the pulse power supply (1); when the first switch (51) and the fourth switch (54) are open, and the second switch (52) and the third switch (53) are closed, the electrode port (6) is connected to the negative pole of the pulse power supply (1), and the workpiece port (7) is connected to the positive pole of the pulse power supply (1).

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