CN117086423A - Micro-hole electric spark machining method and system for online electrode trimming - Google Patents
Micro-hole electric spark machining method and system for online electrode trimming Download PDFInfo
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- CN117086423A CN117086423A CN202311227559.3A CN202311227559A CN117086423A CN 117086423 A CN117086423 A CN 117086423A CN 202311227559 A CN202311227559 A CN 202311227559A CN 117086423 A CN117086423 A CN 117086423A
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- 238000003754 machining Methods 0.000 title claims abstract description 144
- 238000009966 trimming Methods 0.000 title claims abstract description 98
- 238000010892 electric spark Methods 0.000 title claims abstract description 14
- 238000000034 method Methods 0.000 title claims description 27
- 238000012545 processing Methods 0.000 claims abstract description 52
- 230000035515 penetration Effects 0.000 claims description 23
- 230000003044 adaptive effect Effects 0.000 claims description 18
- 125000004122 cyclic group Chemical group 0.000 claims description 10
- 238000001514 detection method Methods 0.000 claims description 10
- 238000004080 punching Methods 0.000 claims description 9
- 230000007246 mechanism Effects 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 7
- 238000007599 discharging Methods 0.000 claims description 5
- 230000007547 defect Effects 0.000 claims description 4
- 230000015556 catabolic process Effects 0.000 claims description 3
- 238000003672 processing method Methods 0.000 claims description 3
- 230000008439 repair process Effects 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000004378 air conditioning Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
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- 239000007769 metal material Substances 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
- B23H9/14—Making holes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H1/00—Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric
- B23H1/02—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H11/00—Auxiliary apparatus or details, not otherwise provided for
Abstract
In the machining process of a workpiece to be machined by a tool electrode, machining is performed in a plurality of continuous cycle machining periods, wherein each cycle machining period consists of a normal forward machining period and a reverse trimming machining period; the positive normal processing period consists of a plurality of positive pulses; in the normal forward machining period, applying forward pulse voltage to the workpiece to be machined and the tool electrode, wherein the forward pulse voltage points to the tool electrode from the workpiece to be machined, and performing electric discharge machining on the workpiece to be machined; the reverse trimming period is composed of a plurality of reverse pulses; in the reverse trimming processing period, applying a reverse pulse voltage to the tool electrode and the workpiece to be processed, wherein the reverse pulse voltage is directed to the workpiece to be processed by the tool electrode, and carrying out discharge trimming on the tool electrode; the forward pulse voltage and the reverse pulse voltage are switched by a control module. The scheme can improve the machining efficiency, the machining quality and the machining consistency of micro-hole electric spark machining.
Description
Technical Field
The invention relates to the technical field of electric spark machining, in particular to a micro-hole electric spark machining method and system for online electrode trimming.
Background
The numerical control electric spark micro-hole processing machine tool is industrial processing equipment, and is used for processing ultra-hard steel, hard alloy, high-temperature alloy and any conductive material, especially the precise micro-holes of difficult-to-process materials, by taking a conductive hollow electrode tube or a micro-electrode wire as a processing tool electrode and performing pulse spark discharge on a workpiece to etch away metal materials of the workpiece so as to realize the processing of the micro-holes.
Because the tool electrode can wear after continuous electric discharge machining work, and because the loss is inhomogeneous, can lead to the electrode tip to become the pointed end shape from normal level shape, lead to discharge energy unbalance, produce the carbon deposition phenomenon, in continuous electric discharge machining process, can lead to workpiece machining unstable, machining precision reduces, and size error increases, leads to the defective rate of machining the workpiece to increase, and manufacturing cost also can improve.
The conventional electrode trimming tool is to perform electrode trimming by changing the polarities of the workpiece end and the electrode end after performing the hole machining and before the next hole machining, for example, by changing the polarities by switching the polarities by external switching means such as a relay, thereby performing etching processing on the electrode end and restoring the electrode end to a flat shape.
However, this conventional repair method requires that the electrode is removed and trimmed after the current hole is machined, and the next hole is machined after trimming is completed, resulting in poor consistency of machined holes; meanwhile, in the traditional repairing mode, the electric spark small hole machine can only repair the electrode after finishing machining of a small hole, the electrode cannot be suspended for repair in the continuous machining process of the small hole, and in the continuous machining process of one time, the electrode end part is gradually worn, so that the machining state is gradually deteriorated.
Aiming at the problems, the proposal of micro-hole electric spark machining for online electrode trimming needs to be provided so as to improve the machining efficiency and the machining quality, ensure the stable machining process and realize high-efficiency machining.
Disclosure of Invention
The invention aims to provide a micro-hole electric spark machining method and system for online electrode trimming.
The technical scheme adopted by the invention is as follows:
an electric spark processing method for micro-holes with online electrode trimming,
in the machining process of a workpiece to be machined by a tool electrode, machining is carried out in a plurality of continuous cycle machining periods, wherein each cycle machining period consists of a normal forward machining period and a reverse finishing machining period;
the positive normal processing period is composed of a plurality of positive pulses; in the normal forward machining period, applying a forward pulse voltage to the workpiece to be machined and the tool electrode, wherein the forward pulse voltage is directed to the tool electrode by the workpiece to be machined, and performing electric discharge machining on the workpiece to be machined;
the reverse finishing period is composed of a plurality of reverse pulses; applying a reverse pulse voltage to the tool electrode and the workpiece to be machined in the reverse trimming machining period, wherein the reverse pulse voltage is directed to the workpiece to be machined by the tool electrode, and carrying out discharge trimming on the tool electrode;
the forward pulse voltage and the reverse pulse voltage are switched by a control module.
According to a further technical scheme, a delay protection period is arranged between the forward normal processing period and the reverse trimming processing period in each cyclic processing period; in the delay protection period, the voltage between the tool electrode and the workpiece to be processed is zero; the delay guard period has a length of 10 to 50 microseconds.
Further technical proposal, has an advanced trimming mechanism, comprising the following matters;
in the normal processing period of the forward direction, detecting an instantaneous pulse voltage peak value of discharge breakdown in each forward direction pulse, and judging that the forward direction pulse is a valid pulse when the instantaneous pulse voltage peak value is larger than or equal to a preset voltage threshold value, otherwise judging that the forward direction pulse is a bad pulse;
for each forward normal processing period, starting from the nth forward pulse, and judging by taking a total of n continuous forward pulses from the forward pulse to the forward pulse as a detection range after each forward pulse is ended, wherein n is a preset natural number smaller than the total number of forward pulses in the forward normal processing period; defining the proportion of the number of bad pulses in the detection range to the total number of pulses as a bad rate, judging whether the bad rate of the detection range is larger than or equal to a preset bad threshold value by the control module, if so, switching the current forward pulse voltage into the reverse pulse voltage so as to enter a suitable reverse trimming period, and if not, continuing to work according to a normal flow;
the adaptive reverse trimming period is composed of a plurality of reverse pulses, and in the adaptive reverse trimming period, reverse pulse voltages are applied to the tool electrode and the workpiece to be machined, and are directed to the workpiece to be machined by the tool electrode, and the tool electrode is subjected to discharge trimming; the duration of the adaptive reverse trimming period and the magnitude of the preset bad threshold value form a positive correlation;
and after the adaptation reverse trimming period is finished, entering the forward normal processing period.
According to a further technical scheme, the preset voltage threshold is 40V.
According to a further technical scheme, the range of the preset bad threshold value is 10-30%; when the preset bad threshold is set to 10%, the duration of the adaptive reverse trimming period is set to 200 milliseconds, and on the basis, each time the set value of the preset bad threshold is increased by 1%, the set duration of the adaptive reverse trimming period is enlarged by 10%.
Further technical proposal, has a pre-penetration trimming mechanism, comprising the following matters;
in the process of processing and punching the workpiece to be processed by the tool electrode, the depth of punching holes is called total penetration depth, and the control module obtains the real-time depth of punching through the feeding distance of the tool electrode;
the ratio of the real-time depth to the total penetration depth is a penetration progress, and when the penetration progress reaches a penetration threshold, the control module switches the current forward pulse voltage to a reverse pulse voltage so as to enter the reverse trimming processing period in advance.
According to a further technical scheme, the penetration threshold is 80-98%.
According to a further technical scheme, the time length of one cyclic processing period is 100ms to 1min.
According to a further technical scheme, the proportion of the reverse trimming processing period to the duration of the cyclic processing period is less than or equal to 10%.
The beneficial effect of this scheme lies in: dividing the machining process of the workpiece to be machined by the tool electrode into a forward normal machining period and a reverse trimming machining period, wherein the switching between the forward normal machining period and the reverse trimming machining period is realized by automatically switching the forward pulse voltage and the reverse pulse voltage on the tool electrode and the workpiece to be machined, the forward normal machining period equipment is in a normal machining state of the workpiece to be machined, the reverse trimming machining period equipment is in a trimming state of the tool electrode, and the two periods are used for carrying out cyclic machining in a cyclic machining period, so that trimming of the tool electrode can be realized in the continuous machining process, and the consistency of machining holes is ensured;
meanwhile, the equipment is circularly switched between the normal machining state and the finishing state in a short time, and the tool electrode is finished after being machined for a short time and when abrasion is not serious, so that the original state of the tool electrode is ensured, the machining stability of the whole process from the hole inlet to the hole outlet in the hole machining process can be ensured, and the machining quality is improved.
A kind of electronic device with high-pressure air-conditioning system:
an electrode online trimming micro-hole electric spark machining system,
comprises a discharging circuit and a control module;
the discharging circuit comprises a pulse power supply, a processing polarity switching working loop, a protection switch and a current limiting resistor which are arranged in series, wherein the pulse power supply externally outputs pulse voltage with the amplitude within the range of 50V to 180V;
the processing polarity switching working loop comprises a first branch and a second branch which are arranged in parallel, wherein a first switch and a third switch which are connected in series are arranged on the first branch, and a second switch and a fourth switch which are connected in series are arranged on the second branch; an electrode port for supplying power to a tool electrode is arranged between the first switch and the third switch, and a workpiece port for supplying power to a workpiece to be processed is arranged between the second switch and the fourth switch;
the control module controls the opening and closing of the first switch, the second switch, the third switch and the fourth switch;
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 with the positive electrode of the pulse power supply, and the workpiece port is connected with the negative electrode of the pulse power supply; when the first switch and the fourth switch are opened and the second switch and the third switch are closed, the electrode port is connected with the negative electrode of the pulse power supply, and the workpiece port is connected with the positive electrode of the pulse power supply.
The beneficial effect of this scheme lies in: when the system works, the positive and negative polarities of the electrode port and the workpiece port can be changed by switching on and off the switches through the control module, so that the tool electrode and the workpiece to be processed are switched between states of being subjected to forward pulse voltage and reverse pulse voltage; when the workpiece to be processed and the tool electrode are in a forward pulse voltage state, the equipment is in a normal processing state of the workpiece to be processed, and when the tool electrode and the workpiece to be processed are in a reverse pulse voltage state, the equipment is in a trimming state of the tool electrode; therefore, the system can enable the equipment to be automatically switched between a normal machining state and a trimming state by the control module, the tool electrode does not need to be moved out to be trimmed, and the continuity of machining can be maintained when the tool electrode is trimmed, so that the machining efficiency is improved; meanwhile, the trimming quality of the tool electrode can be ensured through the cyclic switching of the normal machining state and the trimming state, and the machining quality is improved.
Drawings
FIG. 1 is a waveform diagram of a cycle process cycle in accordance with an embodiment of the present invention;
FIG. 2 is a flow chart of a processing method in an embodiment of the invention;
FIG. 3 is a schematic circuit diagram of a processing system according to an embodiment of the present invention.
In the above figures: 1. a pulse power supply; 2. a working circuit for switching the working polarity; 3. a protection switch; 4. a current limiting resistor; 51. a first switch; 52. a second switch; 53. a third switch; 54. a fourth switch; 6. an electrode port; 7. a workpiece port; t, circulating processing period; t1, normal processing time period in the forward direction; t2, reversely trimming the processing time period; t3, adapting to the reverse trimming period; t4. delay the guard period; t1, forward pulse; t2. reverse pulse.
Description of the embodiments
The invention is further described below with reference to the accompanying drawings and examples:
the present invention will be described in detail with reference to the drawings, wherein modifications and variations are possible in light of the teachings of the present invention, without departing from the spirit and scope of the present invention, as will be apparent to those of skill in the art upon understanding the embodiments of the present invention.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. Singular forms such as "a," "an," "the," and "the" are intended to include the plural forms as well, as used herein.
The terms "first," "second," and the like, as used herein, do not denote a particular order or sequence, nor are they intended to be limiting, but rather are merely used to distinguish one element or operation from another in the same technical term.
As used herein, "connected" or "positioned" may refer to two or more components or devices in physical contact with each other, or indirectly, or in operation or action with each other.
As used herein, the terms "comprising," "including," "having," and the like are intended to be open-ended terms, meaning including, but not limited to.
The term (terms) as used herein generally has the ordinary meaning of each term as used in this field, in this disclosure, and in the special context, unless otherwise noted. Certain terms used to describe the disclosure are discussed below, or elsewhere in this specification, to provide additional guidance to those skilled in the art in light of the description of the disclosure.
The terms "front", "rear", "upper", "lower", "left", "right" and the like used herein are directional terms, and are merely used to describe positional relationships among the structures in the present application, and are not intended to limit the scope of the present application and the specific direction in actual implementation.
As shown in fig. 1 and 2, an on-line electrode trimming micro-hole electric spark machining method is provided, which specifically includes the following steps:
in the machining process of the tool electrode on a workpiece to be machined, machining is performed in a plurality of continuous cycle machining periods T, wherein each cycle machining period T consists of a normal forward machining period T1 and a finishing reverse machining period T2.
Wherein the forward normal processing period T1 is composed of a plurality of forward pulses T1; in the normal forward machining period T1, forward pulse voltage is applied to the workpiece to be machined and the tool electrode, and the forward pulse voltage is directed to the tool electrode from the workpiece to be machined, so that the workpiece to be machined is subjected to electric discharge machining; the reverse trimming 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, the reverse pulse voltage being directed from the tool electrode to the workpiece to be processed, and the tool electrode is subjected to electric discharge trimming.
The forward pulse voltage and the reverse pulse voltage are switched by a control module, so that the forward normal machining period T1, the reverse trimming machining period T2 and the forward normal machining period T1 are alternately and circularly operated in the machining process.
The machining process of the workpiece to be machined by the tool electrode is divided into a forward normal machining period T1 and a reverse trimming machining period T2, and the switching between the forward normal machining period T1 and the reverse trimming machining period T2 is realized by automatically switching the forward pulse voltage and the reverse pulse voltage on the tool electrode and the workpiece to be machined, wherein the forward normal machining period T1 is in a normal machining state of the workpiece to be machined, the reverse trimming machining period T2 is in a trimming state of the tool electrode, and the two periods are used as a cycle machining period T for cycle machining, so that trimming of the tool electrode can be realized in the continuous machining process, and the machining efficiency is ensured.
Meanwhile, the equipment is circularly switched between the normal machining state and the trimming state in a short time, and the tool electrode is trimmed after being machined for a short time and when abrasion is not serious, so that the working state of the tool electrode is ensured, the machining stability of the whole process from the hole inlet to the hole outlet in the hole machining process can be ensured, and the machining quality is improved.
In this embodiment, the time length of one cycle machining period T is 100ms to 1min, and in this interval, the machining state of the tool electrode is not affected due to overlong time, and the efficiency and quality of the machined hole of the workpiece to be machined are not affected due to frequent circuit switching caused by overlong time.
The proportion of the reverse trimming processing period T2 to the cyclic processing period T is less than or equal to 10%, so that a small amount of time is spent for trimming, and meanwhile, most of time is reserved for the forward normal processing period T1 to process the workpiece to be processed, and the overall processing efficiency is ensured.
In this embodiment, the forward pulse t1 is composed of a forward discharge pulse width and a forward pulse width, and the reverse pulse t2 is composed of a reverse discharge pulse width and a reverse pulse width; the pulse length of the forward pulse t1 and the pulse length of the reverse pulse t2 are less than or equal to 500 microseconds, so that basic processing requirements can be met, and the processing effect is better when the pulse length is smaller; 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, so that a good processing effect can be achieved.
In this embodiment, in each of the cycle machining periods T, a delay protection period T4 is provided between the forward normal machining period T1 and the reverse finishing machining period T2, so as to protect equipment; in the delay protection period T4, the voltage between the tool electrode and the workpiece to be processed is zero; the delay protection period T4 has a length of 10 to 50 microseconds.
In the embodiment of the method, an advanced trimming mechanism is further provided, which comprises the following contents;
in the normal forward processing period T1, detecting an instantaneous pulse voltage peak value of discharge breakdown in each forward pulse T1, and when the instantaneous pulse voltage peak value is greater than or equal to a preset voltage threshold value, determining that the forward pulse T1 is a valid pulse, otherwise, determining that the forward pulse T1 is a bad pulse; in this embodiment, the preset voltage threshold is 40V.
For each normal forward processing period T1, starting from the nth forward pulse T1, after each forward pulse T1 is finished, judging by taking the total n continuous forward pulses T1 from the forward pulse T1 to the forward pulse T1 as a detection range, wherein n is a preset natural number smaller than the total number of the forward pulses T1 in the normal forward processing period T1; defining the ratio of the number of bad pulses in the detection range to the total number of pulses as a bad rate, wherein the total number of pulses refers to the number of forward pulses T1 in the detection range, judging whether the bad rate in the detection range is larger than or equal to a preset bad threshold value by the control module, if so, switching the current forward pulse voltage into the reverse pulse voltage to enter an adaptive reverse trimming period T3, and if not, continuing to work according to the normal flow.
The adaptive reverse trimming period T3 consists of a plurality of reverse pulses T2, and in the adaptive reverse trimming period T3, reverse pulse voltages are applied to the tool electrode and the workpiece to be processed, and the reverse pulse voltages are directed to the workpiece to be processed by the tool electrode to perform discharge trimming on the tool electrode; the duration of the adaptive reverse trimming period T3 and the magnitude of the preset bad threshold value form a positive correlation; the forward normal machining period T1 is entered after the end of the adaptive reverse trimming period T3.
By the advanced trimming mechanism, the workpiece can be immediately switched to the trimming state under the condition of poor machining state, and the current normal forward machining period T1 is not required to be ended, and then the workpiece enters the reverse trimming machining period T2 to be trimmed, so that the overall machining quality of the workpiece to be machined can be ensured.
Specifically, the preset failure threshold value is in the range of 10% to 30%, and can be set in the range; when the preset bad threshold is set to 10%, the duration of the adaptive reverse trimming period T3 is set to 200 milliseconds, and on the basis, each 1% of the set value of the preset bad threshold is increased, the set duration of the adaptive reverse trimming period T3 is enlarged by 10%; that is, the larger the preset defect threshold, the longer the required trimming time, which is in accordance with the actual situation.
In the embodiment of the method, a pre-penetration trimming mechanism is also provided, which comprises the following contents;
in the process of processing and punching the workpiece to be processed by the tool electrode, the depth of punching holes is called total penetration depth, and the control module obtains the real-time depth of punching through the feeding distance of the tool electrode; the ratio of the real-time depth to the total penetration depth is a penetration progress, and when the penetration progress reaches a penetration threshold, the control module switches the current forward pulse voltage to a reverse pulse voltage so as to enter the reverse trimming processing period T2 in advance.
In practical implementation, an operator may select and set the penetration threshold according to practical situations, such as the depth of the hole to be punched and other data.
By the aid of the pre-penetration trimming mechanism, the tool electrode can be trimmed before the workpiece to be machined is penetrated, so that the tool electrode is perforated and penetrated in the best machining state, and machining quality during penetration is guaranteed.
As shown in fig. 3, a micro-hole electric discharge machining system for online electrode trimming is further provided, which is used for implementing the micro-hole electric discharge machining method for online electrode trimming, and includes a discharge circuit and a control module.
The discharging circuit comprises a pulse power supply 1, a processing polarity switching working loop 2, a protection switch 3 and a current limiting resistor 4 which are arranged in series, wherein the pulse power supply 1 externally outputs pulse voltage with the amplitude within the range of 50V to 180V.
The machining polarity switching working circuit 2 comprises a first branch and a second branch which are arranged in parallel, wherein a first switch 51 and a third switch 53 which are connected in series are arranged on the first branch, and a second switch 52 and a fourth switch 54 which are connected in series are arranged on the second branch; an electrode port 6 for supplying power to a tool electrode is arranged 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 arranged between the second switch 52 and the fourth switch 54.
In the design of the working 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 opened, the electrode port 6 is connected with the positive electrode of the pulse power supply 1, and the workpiece port 7 is connected with the negative electrode of the pulse power supply 1; in this state, the discharge circuit applies a reverse pulse voltage directed from the tool electrode to the workpiece to be machined to the tool electrode and the workpiece to be machined, and the apparatus is in a state of trimming the tool electrode.
When the first switch 51 and the fourth switch 54 are opened and the second switch 52 and the third switch 53 are closed, the electrode port 6 is connected to the negative electrode of the pulse power source 1, and the workpiece port 7 is connected to the positive electrode of the pulse power source 1; in this state, the discharge circuit applies a forward pulse voltage directed from the workpiece to be machined to the tool electrode and the workpiece to be machined, and the apparatus is in a normal machining state of the workpiece to be machined.
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, so that the opening and closing of each switch can be automatically switched through the control module, and the working state of the equipment can be further switched; in this embodiment, the control module is a single-chip microcomputer, the first switch 51, the second switch 52, the third switch 53 and the fourth switch 54 are all insulated gate bipolar transistor switches, and the specific structure and the working principle of the control module are well known to those skilled in the art and are not the points of the present invention, so that the detailed description is omitted herein.
When the processing system works, the positive and negative polarities of the electrode port 6 and the workpiece port 7 can be changed by switching on and off the switches through the control module, so that the tool electrode and the workpiece to be processed are switched 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 a forward pulse voltage state, the equipment is in a normal processing state of the workpiece to be processed, and when the tool electrode and the workpiece to be processed are in a reverse pulse voltage state, the equipment is in a trimming state of the tool electrode; therefore, the system can enable the equipment to be automatically switched between a normal machining state and a trimming state by the control module, the tool electrode does not need to be moved out to be trimmed, the tool electrode can be trimmed online in real time in the machining process, and the consistency and the machining continuity of machined holes are maintained, so that the machining efficiency is improved; meanwhile, the trimming quality of the tool electrode can be ensured through the cyclic switching of the normal machining state and the trimming state, and the machining quality is improved.
In practical implementation, the micro-hole electric discharge machining method may be implemented by a machining system having other circuit structures with the same or similar functions, and is not limited to the machining system in the present embodiment.
The above embodiments are provided to illustrate the technical concept and features of the present invention and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.
Claims (10)
1. An electric spark machining method for micro holes with online electrode trimming is characterized in that:
in the machining process of a workpiece to be machined by a tool electrode, machining is carried out in a plurality of continuous cycle machining periods (T), and each cycle machining period (T) consists of a normal forward machining period (T1) and a reverse finishing machining period (T2);
the forward normal machining period (T1) is composed of a plurality of forward pulses (T1); applying a forward pulse voltage to the workpiece to be machined and the tool electrode in the forward normal machining period (T1), wherein the forward pulse voltage is directed to the tool electrode by the workpiece to be machined, and performing electric discharge machining on the workpiece to be machined;
the reverse finishing period (T2) is composed of a plurality of reverse pulses (T2); applying a reverse pulse voltage to the tool electrode and the workpiece to be machined in the reverse trimming machining period (T2), the reverse pulse voltage being directed to the workpiece to be machined by the tool electrode, and performing discharge trimming on the tool electrode;
the forward pulse voltage and the reverse pulse voltage are switched by a control module.
2. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 1, wherein: in each cycle machining period (T), a delay protection period (T4) is provided between the forward normal machining period (T1) and the reverse finishing machining period (T2); in the delay protection period (T4), the voltage between the tool electrode and the workpiece to be processed is zero; the delay protection period (T4) has a length of 10 to 50 microseconds.
3. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 1, wherein: having an advanced trimming mechanism, including the following;
in the normal forward processing period (T1), detecting an instantaneous pulse voltage peak value of discharge breakdown in each forward pulse (T1), and judging that the forward pulse (T1) is a valid pulse when the instantaneous pulse voltage peak value is greater than or equal to a preset voltage threshold value, otherwise judging that the forward pulse (T1) is a bad pulse;
for each forward normal processing period (T1), starting from an nth forward pulse (T1) therein, and after each forward pulse (T1) is finished, judging by taking a total of n continuous forward pulses (T1) from the forward pulse (T1) to the forward pulse (T1) as a detection range, wherein n is a preset natural number smaller than the total number of the forward pulses (T1) in the forward normal processing period (T1); defining the ratio of the number of bad pulses in the detection range to the total number of pulses as a bad rate, judging whether the bad rate of the detection range is larger than or equal to a preset bad threshold value by the control module, if so, switching the current forward pulse voltage into the reverse pulse voltage so as to enter a suitable reverse trimming period (T3), and if not, continuing to work according to a normal flow;
the adaptive reverse trimming period (T3) is composed of a plurality of reverse pulses (T2), and in the adaptive reverse trimming period (T3), a reverse pulse voltage is applied to the tool electrode and the workpiece to be machined, and the reverse pulse voltage is directed to the workpiece to be machined by the tool electrode, so that the tool electrode is subjected to discharge trimming; the duration of the adaptive reverse trimming period (T3) and the magnitude of the preset bad threshold value form a positive correlation;
the forward normal machining period (T1) is entered after the end of the adaptive reverse finishing period (T3).
4. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 3, wherein: the preset voltage threshold is 40V.
5. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 3, wherein: the preset poor threshold value ranges from 10% to 30%; when the preset defect threshold is set to 10%, the duration of the adaptive reverse trimming period (T3) is set to 200 milliseconds, and on the basis of the preset defect threshold, each time the set value of the preset defect threshold is increased by 1%, the set duration of the adaptive reverse trimming period (T3) is enlarged by 10%.
6. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 1, wherein: having a pre-penetration trimming mechanism, including the following;
in the process of processing and punching the workpiece to be processed by the tool electrode, the depth of punching holes is called total penetration depth, and the control module obtains the real-time depth of punching through the feeding distance of the tool electrode;
the ratio of the real-time depth to the total penetration depth is a penetration progress, and when the penetration progress reaches a penetration threshold, the control module switches the current forward pulse voltage to a reverse pulse voltage so as to enter the reverse trimming processing period (T2) in advance.
7. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 6, wherein: the penetration threshold is 80% to 98%.
8. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 1, wherein: the time length of one of the cyclic processing periods (T) is 100ms to 1min.
9. The method for on-line electrode trimming micro-hole electric discharge machining according to claim 8, wherein: the proportion of the reverse finishing machining period (T2) to the duration of the cyclic machining period (T) is less than or equal to 10%.
10. An electrode online trimming micro-hole electric spark machining system is characterized in that: for implementing the processing method of any one of claims 1 to 9;
comprises a discharging circuit and a control module;
the discharging circuit comprises a pulse power supply (1), a processing polarity switching working loop (2), a protection switch (3) and a current limiting resistor (4) which are arranged in series, wherein the pulse power supply (1) externally outputs pulse voltage with the amplitude within the range of 50V to 180V;
the processing polarity switching working loop (2) comprises a first branch and a second branch which are arranged in parallel, wherein a first switch (51) and a third switch (53) which are connected in series are arranged on the first branch, and a second switch (52) and a fourth switch (54) which are connected in series are arranged on the second branch; an electrode port (6) for supplying power to a tool electrode is arranged between the first switch (51) and the third switch (53), and a workpiece port (7) for supplying power to a workpiece to be processed is arranged 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 with the positive electrode of the pulse power supply (1), and the workpiece port (7) is connected with the negative electrode of the pulse power supply (1); when the first switch (51) and the fourth switch (54) are opened and the second switch (52) and the third switch (53) are closed, the electrode port (6) is connected with the negative electrode of the pulse power supply (1), and the workpiece port (7) is connected with the positive electrode of the pulse power supply (1).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311227559.3A CN117086423A (en) | 2023-09-22 | 2023-09-22 | Micro-hole electric spark machining method and system for online electrode trimming |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311227559.3A CN117086423A (en) | 2023-09-22 | 2023-09-22 | Micro-hole electric spark machining method and system for online electrode trimming |
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| Publication Number | Publication Date |
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| CN117086423A true CN117086423A (en) | 2023-11-21 |
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| CN202311227559.3A Pending CN117086423A (en) | 2023-09-22 | 2023-09-22 | Micro-hole electric spark machining method and system for online electrode trimming |
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| Country | Link |
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| CN (1) | CN117086423A (en) |
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