CN110621431B - Electric discharge machining apparatus and method for controlling lifting operation - Google Patents
Electric discharge machining apparatus and method for controlling lifting operation Download PDFInfo
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- CN110621431B CN110621431B CN201880003617.5A CN201880003617A CN110621431B CN 110621431 B CN110621431 B CN 110621431B CN 201880003617 A CN201880003617 A CN 201880003617A CN 110621431 B CN110621431 B CN 110621431B
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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
- B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
- B23H7/14—Electric circuits specially adapted therefor, e.g. power supply
- B23H7/20—Electric circuits specially adapted therefor, e.g. power supply for programme-control, e.g. adaptive
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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
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Abstract
An electric discharge machining apparatus includes: a material information input unit (2) that receives input of information on the electrode material and the workpiece material; a machining condition input unit (3) that receives an input of a machining condition for electric discharge machining; a discharge pulse detection unit (8) that detects a discharge pulse generated during electric discharge machining; a discharge pulse number accumulation unit (9) that accumulates the number of discharge pulses; a lift action control unit (7) that controls the lift action on the basis of the lift condition of the lift action of the electrode (131) included in the machining condition; a storage unit (4) for storing an optimum value of the number of discharge pulses per unit time in electric discharge machining, which is determined according to a combination of an electrode material and a workpiece material; a comparison unit (5) that compares the optimal value with the integrated value; and a lifting parameter adjusting unit (6) that adjusts the lifting conditions based on the comparison result between the optimal value and the integrated value, wherein the lifting action control unit (7) controls the lifting action in accordance with the content adjusted by the lifting parameter adjusting unit (6).
Description
Technical Field
The present invention relates to an electric discharge machining apparatus for performing electric discharge machining and a lift operation control method.
Background
In an electric discharge machining apparatus that performs the die sinking electric discharge machining, if the number of electric discharge pulses per unit time deviates from an optimum range, i.e., a so-called optimum value, the machining speed decreases, and efficient electric discharge machining cannot be performed. In order to perform electric discharge machining efficiently, the electric discharge machining apparatus needs to secure the number of electric discharge pulses to an optimum value. The number of discharge pulses is affected by the concentration of machining chips deposited in the machining gap between the electrode filled with the machining liquid and the workpiece. In the electric discharge machining apparatus, when the machining chip concentration is too high, the machining chips need to be removed in order to ensure the number of electric discharge pulses to an optimum value.
One of the methods for removing machining chips in an electric discharge machining apparatus is to move an electrode up and down, i.e., to perform a so-called lift operation. The electric discharge machine can remove machining chips efficiently by increasing the lifting distance (hereinafter referred to as the lifting distance) of the electrode during the lifting operation. However, the electric discharge machine interrupts machining during the electrode lifting process, and thus if the lifting distance is increased, the machining efficiency is lowered. In addition, in the electric discharge machining apparatus, by shortening a period of a state in which the electrode is lowered from the time when the electrode is lowered to the time when the electrode is lifted, that is, a period of machining between the lifting operation and the next lifting operation (hereinafter, referred to as a lifting and lowering time), the machining amount is reduced in 1 lifting and lowering time, and the amount of machining chips generated can be reduced. However, in the electric discharge machine, since the lift-down time is shortened and the time for interrupting the machining is increased, the machining efficiency is also lowered in this case.
In the electric discharge machine, the ease of removing machining chips varies depending on the shape and size of the electrode, the depth of machining in the workpiece, and the like. Therefore, the electric discharge machine monitors the machining state for efficient machining, and needs to control the lifting operation in accordance with the machining state. Patent document 1 discloses a technique in which an electric discharge machining apparatus controls a lift operation based on a result of comparing the number of discharge pulses in the previous machining with the number of discharge pulses in the current machining.
Patent document 1: japanese patent laid-open No. 2000-153409
Disclosure of Invention
In addition, when the electric discharge machining apparatus performs machining in a state where the machining chip concentration is too small, the electric discharge pulse is hard to be generated, and therefore the machining speed is reduced, and efficient machining cannot be performed. That is, in order to ensure the number of discharge pulses to an optimum value and perform efficient and highly accurate machining, it is important for the electric discharge machining apparatus to ensure that the machining chip concentration in the machining gap is an optimum value that is neither too small nor too large.
However, as in the electric discharge machining apparatus described in patent document 1, there is a problem that it is difficult to ensure the number of discharge pulses to an optimum value only by comparing the number of discharge pulses in the previous machining with the number of discharge pulses in the current machining.
The present invention has been made in view of the above circumstances, and an object thereof is to obtain an electric discharge machining apparatus capable of achieving efficient electric discharge machining.
In order to solve the above problems and achieve the object, an electric discharge machining apparatus according to the present invention includes: a material information input unit that receives input of information on an electrode material that is a material of an electrode used for electric discharge machining and information on a workpiece material that is a material of a workpiece to be electric discharge machined; a machining condition input unit that receives an input of a machining condition for electric discharge machining; a discharge pulse detection unit that detects a discharge pulse generated during electric discharge machining; and a discharge pulse number integrating unit that integrates the number of discharge pulses and calculates an integrated value of the discharge pulses per unit time. Further, the electric discharge machining apparatus includes: a lift action control unit for controlling the lift action based on the lift condition of the lift action of the electrode included in the processing condition; a storage unit that stores an optimum value of the number of discharge pulses per unit time in electric discharge machining, which is determined according to a combination of an electrode material and a workpiece material; a comparison unit that compares the optimal value with the integrated value; and a lift parameter adjustment unit that adjusts the lift condition based on the comparison result between the optimum value and the integrated value. The lifting action control part controls the lifting action according to the content adjusted by the lifting parameter adjusting part.
ADVANTAGEOUS EFFECTS OF INVENTION
The electric discharge machining apparatus according to the present invention has an effect of enabling efficient electric discharge machining.
Drawings
Fig. 1 is a block diagram showing a configuration example of an electric discharge machine according to embodiment 1.
Fig. 2 is a diagram showing an optimum value of the number of discharge pulses per unit time determined according to a combination of an electrode material and a workpiece material, which is stored in a storage unit of the electric discharge machining apparatus according to embodiment 1.
Fig. 3 is a flowchart showing a control method of the lift-up operation for ensuring the optimum number of discharge pulses generated in the electric discharge machining apparatus according to embodiment 1.
Fig. 4 is a diagram showing the relationship between the grade of the current machining state based on the ratio of the integrated value to the optimum value and the magnification of the parameter with respect to the lift condition in each grade in the electric discharge machining apparatus according to embodiment 1.
Fig. 5 is a diagram showing an example in which a processing circuit included in the electric discharge machining apparatus according to embodiment 1 is configured by a processor and a memory.
Fig. 6 is a block diagram showing a configuration example of the electric discharge machine according to embodiment 2.
Fig. 7 is a diagram showing an optimum value of the number of discharge pulses per unit time, which is stored in the storage unit of the electric discharge machining apparatus according to embodiment 2 and is determined by a combination of the electrode material, the workpiece material, the machining area, and the machining conditions.
Fig. 8 is a flowchart showing a control method of the lift-up operation for ensuring the optimum number of discharge pulses generated in the electric discharge machining apparatus according to embodiment 2.
Detailed Description
Next, an electric discharge machine and a lift operation control method according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the present embodiment.
Fig. 1 is a block diagram showing a configuration example of an electric discharge machine 1 according to embodiment 1 of the present invention. The electric discharge machining apparatus 1 includes a material information input unit 2, a machining condition input unit 3, a storage unit 4, a comparison unit 5, a lift parameter adjustment unit 6, a lift operation control unit 7, a discharge pulse detection unit 8, a discharge pulse number accumulation unit 9, a Z-axis motor control unit 10, a Z-axis motor 11, a machining power supply control unit 12, a machining unit 13, a machining speed calculation unit 14, a machining result storage unit 15, and an update unit 16. The processing unit 13 includes: an electrode 131 used for electric discharge machining; and a workpiece 132 to be processed by electric discharge machining.
The material information input unit 2 receives input of information on the material of the electrode 131 and information on the material of the workpiece 132 from a user. The material information input unit 2 stores the received information on the material of the electrode 131 and the information on the material of the workpiece 132 in the storage unit 4. In the following description, the material of the electrode 131 is sometimes referred to as an electrode material, and the material of the workpiece 132 is sometimes referred to as a workpiece material.
The machining condition input unit 3 receives an input of a machining condition for electric discharge machining from a user. The machining condition input unit 3 stores the received machining conditions in the storage unit 4. The machining condition input unit 3 outputs the received machining conditions to the machining power supply control unit 12 and the lift operation control unit 7. The machining conditions for electric discharge machining include a machining voltage as a voltage applied to the electrode 131, a machining current as a current flowing through the electrode 131, an application time during which the machining voltage is applied, a non-application time during which the machining voltage is not applied, and a lift condition indicating an operation condition for a lift operation of the electrode 131.
The storage unit 4 stores the electrode material and the workpiece material input to the material information input unit 2, and the machining condition of the electric discharge machining input to the machining condition input unit 3. The storage unit 4 stores an optimum value of the number of discharge pulses per unit time in the electric discharge machining, which is determined according to the combination of the electrode material and the workpiece material. The optimum value of the number of discharge pulses per unit time is the number of discharge pulses generated per unit time, which is preset for achieving efficient electric discharge machining, in a combination of a specified electrode material and a workpiece material. Generally, the ease of generating the discharge pulse may vary depending on the combination of the electrode material and the workpiece material. That is, the optimum value of the number of discharge pulses per unit time is affected by the combination of the electrode material and the workpiece material. Fig. 2 is a diagram showing an optimum value of the number of discharge pulses per unit time determined from a combination of an electrode material and a workpiece material, which is stored in the storage unit 4 of the electric discharge machining apparatus 1 according to embodiment 1. The storage unit 4 stores an optimum value corresponding to a combination of the electrode material and the workpiece material. In the case where the electrode material is copper and the workpiece material is iron, for example, N1 is stored in the storage unit 4 as an optimum value of the number of discharge pulses per unit time. The user may set the information of the optimum value corresponding to the combination of the electrode material and the workpiece material in the storage unit 4 via the material information input unit 2 or the like, or may set the information of the optimum value in the storage unit 4 via a storage medium, not shown, generated by an external computer. The optimum value of the number of discharge pulses per unit time shown in fig. 2 is an initial value, and may be updated by a process during electric discharge machining in the electric discharge machining apparatus 1 described later. The electric discharge machine 1 updates the optimum value of the number of electric discharge pulses per unit time so that the machining efficiency becomes maximum during machining. In the following description, the optimum value of the number of discharge pulses per unit time may be simply referred to as an optimum value.
The comparing unit 5 compares the optimum value stored in the storage unit 4 with the integrated value of the discharge pulses per unit time calculated by the discharge pulse number integrating unit 9.
The lift parameter adjusting unit 6 adjusts the lift condition of the lift operation performed by the lift operation control unit 7 based on the comparison result of the comparing unit 5. The parameters of the lifting condition include a lifting distance indicating a lifting distance when the electrode 131 is lifted, a lifting/lowering time indicating a period in which the electrode 131 is closest to the workpiece 132, a lifting speed that is a lifting speed of the electrode 131, and the like. Specifically, the lifting parameter adjusting unit 6 adjusts the lifting conditions by setting the magnification for each parameter such as the lifting distance, the lifting/lowering time, and the lifting speed based on the comparison result.
The lift operation controller 7 controls the lift operation of the electrode 131 based on the lift condition included in the machining condition input by the machining condition input unit 3 and the magnification of each parameter for the lift condition set by the lift parameter adjuster 6. That is, the lifting operation control unit 7 controls the lifting operation in accordance with the content adjusted by the lifting parameter adjustment unit 6.
The discharge pulse detection unit 8 detects a discharge pulse generated between the electrode 131 and the workpiece 132 by the machining unit 13 during electric discharge machining.
The discharge pulse number integrating unit 9 integrates the number of discharge pulses detected by the discharge pulse detecting unit 8, and calculates an integrated value of the discharge pulses per unit time.
The Z-axis motor control unit 10 controls the operation of the Z-axis motor 11 that operates the main shaft, not shown, of the holding electrode 131.
The Z-axis motor 11 moves a main shaft, not shown, of the holding electrode 131 in the Z-axis direction, that is, in the vertical direction, based on the control of the Z-axis motor control unit 10.
The machining power supply control unit 12 supplies machining power to the electrode 131 based on the machining condition of the electric discharge machining input by the machining condition input unit 3. As described above, the machining conditions of the electric discharge machining include a machining voltage, a machining current, an application time, a non-application time, and the like.
The machining unit 13 performs electric discharge machining on a workpiece 132, which is disposed in a machining tank, not shown, so as to face the electrode 131, using the electrode 131.
The machining speed calculation unit 14 calculates a machining speed of the electric discharge machining in the machining unit 13.
The machining result storage unit 15 stores the integrated value calculated by the discharge pulse number integrating unit 9 and the machining speed calculated by the machining speed calculating unit 14. The machining result storage unit 15 stores at least the latest current accumulated value and machining speed and the latest previous accumulated value and machining speed.
The updating unit 16 updates the optimum value stored in the storage unit 4 based on the accumulated value and the machining speed stored in the machining result storage unit 15 in order to maximize the machining efficiency.
In addition, in the electric discharge machine 1 shown in fig. 1, components related to the lifting operation performed in the present embodiment are described. Therefore, in the electric discharge machine 1 shown in fig. 1, an X-axis motor and a Y-axis motor for moving the workpiece 132 in a 2-dimensional direction, which is a horizontal direction, an X-axis motor control unit for controlling the operation of the X-axis motor, a Y-axis motor control unit for controlling the operation of the Y-axis motor, and the like are not described.
Next, control for ensuring the number of discharge pulses generated by the electric discharge machine 1 to an optimum value will be described. In the present embodiment, when the integrated value of the discharge pulses is smaller than the optimum value, the electric discharge machining apparatus 1 is expected to control the lifting operation so that the machining chip concentration increases because the machining chip concentration is too small to generate the discharge pulses. In addition, when the integrated value of the discharge pulses is larger than the optimum value, the electric discharge machining apparatus 1 is expected to reduce the machining chip concentration by controlling the lift operation in such a manner that the machining chip concentration is excessively increased and the discharge pulses are abnormal. Since there is a correlation between the number of discharge pulses and the machining chip concentration, the electric discharge machining apparatus 1 can ensure the number of discharge pulses to an optimum value by controlling the lift operation so that the machining chip concentration is ensured to an optimum value. Fig. 3 is a flowchart showing a control method of the lift-up operation for ensuring the optimum number of discharge pulses generated during electric discharge machining in the electric discharge machining apparatus 1 according to embodiment 1.
In the electric discharge machine 1, the material information input unit 2 receives the input of the electrode material and the workpiece material from the user (step S1). The material information input unit 2 stores the input electrode material and the input workpiece material in the storage unit 4.
The machining condition input unit 3 receives an input of a machining condition for electric discharge machining based on a specification required for the workpiece 132 from a user (step S2). The machining condition input unit 3 stores the input machining conditions in the storage unit 4. The machining condition input unit 3 outputs the input machining conditions to the machining power supply control unit 12 and the lift operation control unit 7.
The machining power supply control unit 12 controls the electric discharge machining of the electrode 131 with respect to the workpiece 132 in accordance with the machining conditions. The lift operation controller 7 controls the Z-axis motor 11 via the Z-axis motor controller 10 according to the lift conditions included in the machining conditions and the magnification set by the lift parameter adjuster 6, and controls the lift operation of the electrode 131. The machining unit 13 starts machining the workpiece 132 under the control of the machining power supply control unit 12 and the lift operation control unit 7 (step S3). At this time, the machining power supply controller 12 sets a machining end flag MFLG indicating whether machining is being performed or not, to the comparator 5. The machining power supply controller 12 sets the machining end flag MFLG to 1 during machining. The machining power supply controller 12 sets the machining end flag MFLG to 0 when the machining under the final condition specified by the machining condition is completed.
Immediately after the start of machining, the discharge pulse detection unit 8 detects a discharge pulse generated between the electrode 131 and the workpiece 132. The discharge pulse number integrating unit 9 integrates the number of discharge pulses detected by the discharge pulse detecting unit 8, and calculates an integrated value of the discharge pulses per unit time (step S4). The unit time is, for example, 100 milliseconds during the lifting and lowering of the electrode 131, but is not limited thereto. The discharge pulse number integrating unit 9 stores the integrated value in the machining result storage unit 15.
The machining speed calculation unit 14 calculates the amount of travel in the machining direction per 1 second, that is, the machining speed of the electric discharge machining in the machining unit 13, based on the difference between the position in the machining direction at which the electric discharge pulse is first generated after the start of machining and the deepest machining position in the machining direction after 1 second has elapsed from the start of machining, for example (step S5). The machining speed calculation unit 14 stores the calculated machining speed in the machining result storage unit 15. The above-described 1 second is an example, and is not limited thereto.
The updating unit 16 compares the latest machining speed at the time of the current lift operation stored in the machining result storage unit 15 with the machining speed at the time of the previous lift operation stored in the machining result storage unit 15 (step S6). When the machining speed at the time of machining before the present lifting operation is higher than the machining speed at the time of machining before the previous lifting operation (Yes in step S6), the updating unit 16 updates the optimum value stored in the storage unit 4 with the latest accumulated value at the time of machining before the present lifting operation, which is stored in the machining performance storage unit 15, in order to maximize the machining efficiency (step S7). When a new integrated value is input from the updating unit 16, the storage unit 4 updates and stores the stored optimum value of the number of discharge pulses by the input integrated value. When the machining speed at the time of the machining before the present lift operation is equal to or less than the machining speed at the time of the machining before the previous lift operation (No at step S6), the update unit 16 omits the processing at step S7. In addition, the machining speed at the time of machining before the current lift operation may be simply referred to as the current machining speed, and the machining speed at the time of machining before the previous lift operation may be simply referred to as the previous machining speed.
The comparing section 5 reads the optimum value of the number of discharge pulses from the storage section 4 (step S8). The comparison unit 5 reads out the calculated integrated value of the discharge pulse from the discharge pulse number integration unit 9 (step S9). The comparison unit 5 checks the value of the machining end flag MFLG (step S10). When the machining end flag MFLG is equal to 0 (step S10: Yes), the comparison unit 5 ends the processing after the machining is completed. When the machining end flag MFLG ≠ 0 (step S10: No), the comparison unit 5 proceeds to the process of step S11.
The comparison unit 5 determines whether or not the integrated value read out from the discharge pulse number integrating unit 9 is equal to the optimum value read out from the storage unit 4 (step S11). Specifically, the comparison unit 5 calculates the ratio of the integrated value to the optimum value by the equation (1). When the calculated ratio includes a decimal, the comparison unit 5 rounds, truncates, or rounds up the decimal to obtain an integer value.
The ratio of the integrated value to the optimum value (integrated value/optimum value) × 100 [% ] … (1)
When the ratio calculated by the equation (1) is 96 to 105 [% ], the comparison unit 5 determines that the integrated value is equal to the optimum value (step S11: Yes), and assigns the current machining state to rank 5 (step S12). Details of the current machining state level are described later. Since the current machining state is level 5, the comparison unit 5 instructs the lift parameter adjustment unit 6 to maintain the current lift condition (step S13). The electric discharge machine 1 returns to the process of step S4 to perform the above-described process. If the value calculated by the formula (1) is not 96 to 105 [% ], the comparison unit 5 determines that the integrated value is different from the optimum value or the like (step S11: No), and the process proceeds to step S14.
When the ratio calculated by the equation (1) is not less than 106 [% ], the comparison unit 5 determines that the integrated value is not less than the optimum value (step S14: Yes), and assigns the current machining state to any one of the ranks 6 to 10 (step S15). Since the current machining state is one of the ranks 6 to 10, the comparison unit 5 instructs the lift parameter adjustment unit 6 to change the lift condition in accordance with the processing described later (step S16). The electric discharge machine 1 returns to the process of step S4 to perform the above-described process.
When the value calculated by the equation (1) is 95 [% ] or less, the comparison unit 5 determines that the integrated value is less than the optimum value (step S14: No), and assigns the current machining state to any one of the ranks 0 to 4 (step S17). Since the current machining state is one of the ranks 0 to 4, the comparison unit 5 instructs the lift parameter adjustment unit 6 to change the lift condition in accordance with the processing described later (step S18). The electric discharge machine 1 returns to the process of step S4 to perform the above-described process.
The electric discharge machine 1 repeats the processing from step S4 to step S18 for each lift operation until the electric discharge machining is completed.
The level of the current machining state and the process of adjusting the lift condition in the lift parameter adjusting unit 6 will be described. Fig. 4 is a diagram showing the relationship between the grade of the current machining state based on the ratio of the integrated value to the optimum value and the magnification of the parameter with respect to the lifting condition in each grade in the electric discharge machining apparatus 1 according to embodiment 1. As described above, the parameters of the lifting condition are the lifting distance, the lifting and lowering time, the lifting speed, and the like. In fig. 4, when the integrated value of the discharge pulse is smaller than the optimum value, that is, in the class 0 to 4, it is expected that the machining chip concentration is too small to generate the discharge pulse, and therefore, the magnifications of the parameters with respect to the lift condition are set so as to increase the machining chip concentration. In fig. 4, when the integrated value of the discharge pulse is larger than the optimum value, that is, in the class 6 to 10, it is expected that the machining chip concentration is too large and the discharge pulse is abnormal, and therefore, the multiplying factor of each parameter with respect to the lift condition is set so as to decrease the machining chip concentration. For example, when the electrode material is copper and the workpiece material is iron, the optimum value of the number of discharge pulses per unit time is N1 from the relationship shown in fig. 2. The comparison unit 5 calculates the ratio of the integrated value to the optimum value by the equation (2) if the integrated value is Nx.
The ratio of the integrated value to the optimum value is (Nx/N1) × 100 [% ] … (2)
The comparison unit 5 assigns the current machining state to any one of the ranks 0 to 10 according to the contents of fig. 4 in accordance with the ratio calculated using the equation (2). For example, when the ratio of the integrated value to the optimum value is 70 [% ], the comparison unit 5 assigns the current machining state to level 2. The lift parameter adjusting unit 6 sets the magnification of each parameter with respect to the lift condition in accordance with the contents of fig. 4 based on the current machining state level assigned by the comparing unit 5. For example, when the current machining state is level 2, the lift parameter adjusting unit 6 sets the magnification as follows according to the contents of fig. 4: the lifting distance set in the lifting condition was changed to 0.7 times, the lifting and lowering time set in the lifting condition was changed to 2.0 times, and the lifting speed set in the lifting condition was changed to 0.7 times. Thus, at the next lift operation, the lift parameter adjusting unit 6 changes the lift conditions included in the machining conditions, specifically, the lift distance L1, the lift/lower time T1, and the lift speed V1, as shown in the following expressions (3) to (5), to the lift operation control unit 7.
The lifting distance of the next lifting action is L1 multiplied by 0.7 … (3)
The rise and fall time of the next rise is T1X 2.0 … (4)
The lifting speed of the next lifting action is V1 multiplied by 0.7 … (5)
As described above, the lift parameter adjustment unit 6 determines the magnification for adjusting each parameter of the lift condition based on the ratio of the integrated value to the optimum value. In fig. 4, the division of the ratio of the integrated value to the optimum value and the magnification that is each parameter are examples, but not limited thereto. The lift parameter adjustment unit 6 may perform adjustment using at least 1 of the magnifications of the lift distance L1, the lift/lower time T1, and the lift speed V1. For example, when the current machining state in which the integrated value is smaller than the optimum value is of the class 0 to 4, the lift parameter adjusting unit 6 sets the magnification to shorten the lift distance, lengthen the lift lowering time, and reduce the lift speed in the next lift operation with respect to the current lift operation, and adjusts the lift condition. When the current machining state in which the integrated value is greater than the optimum value is at a level of 6 to 10, the lift parameter adjustment unit 6 sets a magnification so as to increase at least 1 of the lift distance, the lift lowering time, and the lift speed in the next lift operation with respect to the current lift operation, and adjusts the lift condition. Further, when the current machining state in which the integrated value is equal to the optimum value is level 5, the lift parameter adjustment unit 6 maintains the setting of the magnification ratio for the present lift condition in the next lift operation. The information shown in fig. 4 may be held by both the comparison unit 5 and the lift parameter adjustment unit 6, or the lift parameter adjustment unit 6 may hold the information shown in fig. 4, and the comparison unit 5 may hold only the rank and the ratio of the integrated value to the optimum value in the information shown in fig. 4.
Next, a hardware configuration of the electric discharge machine 1 will be explained. In the electric discharge machine 1, the material information input unit 2 and the machining condition input unit 3 are a keyboard, a mouse, and the like used in a computer. The storage unit 4 and the machining result storage unit 15 are memories. The comparison unit 5, the lift parameter adjustment unit 6, the lift operation control unit 7, the discharge pulse detection unit 8, the discharge pulse number integration unit 9, the Z-axis motor control unit 10, the machining power supply control unit 12, the machining speed calculation unit 14, and the update unit 16 are implemented by a processing circuit. The processing circuit may be a processor and a memory that execute a program stored in the memory, or may be dedicated hardware.
Fig. 5 is a diagram showing an example in which the processing circuit of the electric discharge machine 1 according to embodiment 1 is configured by a processor and a memory. When the processing circuit includes the processor 91 and the memory 92, each function of the processing circuit of the electric discharge machine 1 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit, each function is realized by reading out and executing a program stored in the memory 92 by the processor 91. That is, the processing circuit includes a memory 92, and the memory 92 stores a program for executing the processing of each component of the electric discharge machine 1 as a result. The programs can be said to be programs for causing a computer to execute the procedure and method of each component of the electric discharge machine 1.
Here, the processor 91 may be a cpu (central Processing unit), a Processing device, an arithmetic device, a microprocessor, a microcomputer, a dsp (digital Signal processor), or the like. The memory 92 corresponds to, for example, a nonvolatile or volatile semiconductor memory such as a ram (random Access memory), a rom (read Only memory), a flash memory, an EPROM (erasable programmable rom), and an EEPROM (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a dvd (digital Versatile disc).
In the case where the processing circuit is formed of dedicated hardware, the processing circuit corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an asic (application Specific integrated circuit), an fpga (field Programmable Gate array), or a combination thereof. Each function of each component of the electric discharge machine 1 may be realized by the processing circuit for each function, or may be realized by the processing circuit in a lump.
Further, the functions of the components of the electric discharge machine 1 may be partly realized by dedicated hardware and partly realized by software or firmware. As described above, the processing circuit can implement the functions described above by dedicated hardware, software, firmware, or a combination thereof.
As described above, according to the present embodiment, the electric discharge machine 1 calculates the integrated value of the discharge pulses per unit time during machining, compares the optimal value of the number of discharge pulses determined by the combination of the electrode material and the workpiece material with the integrated value, and controls the lifting operation of the electrode 131 based on the comparison result. When the lifting operation needs to be changed, the electric discharge machine 1 sets the magnification of each parameter with respect to the lifting condition included in the machining condition, and adjusts the lifting condition. Thus, the electric discharge machining apparatus 1 can ensure the number of discharge pulses per unit time during machining to an optimum value, and can realize efficient and stable electric discharge machining. Further, the electric discharge machine 1 does not need to store the lift condition set in the previous lift operation, and therefore, can realize efficient and stable electric discharge machining by simple control.
In addition, the electric discharge machine 1 may store, in the storage unit 4, a 1 st calculated value obtained by performing predetermined arithmetic processing on the optimum value instead of the optimum value. In this case, in the electric discharge machine 1, the discharge pulse number integrating unit 9 performs the predetermined arithmetic processing described above on the integrated value to calculate the 2 nd calculated value. The electric discharge machining apparatus 1 performs a process of comparing a 1 st calculated value based on the optimum value and a 2 nd calculated value based on the integrated value, instead of the process of comparing the optimum value and the integrated value. When the 1 st calculated value stored in the storage unit 4 is updated based on the machining speed, the electric discharge machining device 1 updates the 2 nd calculated value. The predetermined arithmetic processing is, for example, addition, subtraction, multiplication, or division of a certain coefficient to the optimum value or the cumulative value, but is not limited to these.
In embodiment 1, the electric discharge machine 1 stores the optimum values determined according to the combination of the electrode material and the workpiece material, and updates the optimum values as appropriate in order to maximize the machining efficiency. However, the optimum value is influenced by the machining area, machining conditions, and the like, in addition to the combination of the electrode material and the workpiece material. In embodiment 2, the electric discharge machining apparatus stores an optimum value determined according to a combination of an electrode material and a workpiece material, a machining area, and machining conditions, and updates the optimum value as appropriate in order to maximize machining efficiency. The differences from embodiment 1 will be described.
Fig. 6 is a block diagram showing a configuration example of an electric discharge machine 1a according to embodiment 2. In the electric discharge machining apparatus 1a, the storage unit 4, the machining result storage unit 15, and the update unit 16 are replaced with the storage unit 4a, the machining result storage unit 15a, and the update unit 16a, and a machining area calculation unit 17 is added to the electric discharge machining apparatus 1 according to embodiment 1 shown in fig. 1.
The machining area calculation unit 17 calculates a machining area for the electric discharge machining of the workpiece 132. The specific calculation method in the machining area calculation unit 17 will be described later.
The storage unit 4a stores the electrode material and the workpiece material input to the material information input unit 2 and the machining conditions of the electric discharge machining input to the machining condition input unit 3. The storage unit 4a stores an optimum value of the electrode material, the workpiece material, the machining area, and the number of discharge pulses per unit time determined according to a combination of machining conditions. Fig. 7 is a diagram showing an optimum value of the number of discharge pulses per unit time, which is determined by a combination of the electrode material, the workpiece material, the machining area, and the machining conditions, and which is stored in the storage portion 4a of the electric discharge machining apparatus 1a according to embodiment 2. The storage unit 4a stores an optimum value corresponding to a combination of the electrode material, the workpiece material, the machining area, and the machining condition. In the case where the electrode material is copper and the workpiece material is iron, for example, the memory portion 4a stores N111 as an optimum value of the number of discharge pulses per unit time in the case where the machining area S1, the machining current I1, the machining voltage application time ON1, and the machining voltage V1 are used. As described above, the machining conditions include the machining current, the machining voltage application time, and the machining voltage, and also include the non-application time during which the machining voltage is not applied, and therefore, the items of the non-application time may be added to fig. 7. The optimum value of the number of discharge pulses per unit time shown in fig. 7 is an initial value, and may be updated by a process during electric discharge machining in the electric discharge machining apparatus 1a described later. The electric discharge machine 1a updates the optimum value of the number of electric discharge pulses per unit time so that the machining efficiency is maximized during machining.
The machining result storage unit 15a stores the integrated value calculated by the discharge pulse number integrating unit 9, the machining speed calculated by the machining speed calculating unit 14, and the machining area calculated by the machining area calculating unit 17. The machining result storage unit 15a stores at least the latest current integrated value, machining speed, and machining area, and the latest previous integrated value, machining speed, and machining area.
The updating unit 16a updates the optimum value stored in the storage unit 4a based on the accumulated value, the machining speed, and the machining area stored in the machining result storage unit 15a in order to maximize the machining efficiency.
Next, control for ensuring the number of discharge pulses generated in the electric discharge machining to an optimum value by the electric discharge machining apparatus 1a will be described. Fig. 8 is a flowchart showing a control method of the lift-up operation for ensuring the optimum number of discharge pulses generated during electric discharge machining in the electric discharge machining apparatus 1a according to embodiment 2. The processing from step S1 to step S5 in the flowchart shown in fig. 8 is the same as the processing from step S1 to step S5 in the flowchart of embodiment 1 shown in fig. 3.
In the electric discharge machining device 1a, the machining area calculation unit 17 calculates the machining area using equation (6) (step S21).
Machining area … (6) is the number of discharge pulses x (machining amount per 1 discharge pulse/travel in the machining direction)
In the equation (6), the machining amount per 1 discharge pulse is determined by a combination of the electrode 131, the workpiece 132, and machining conditions in which machining voltage, machining current, and the like are set, and is stored in a machining amount storage unit, not shown, in the electric discharge machining apparatus 1 a. The machining area calculation unit 17 stores the calculated machining area in the machining result storage unit 15 a.
The updating unit 16a compares the latest machining speed at the time of the current lift operation stored in the machining result storage unit 15a with the machining speed at the time of the previous lift operation stored in the machining result storage unit 15a (step S6). When the machining speed at the time of the machining before the present lift operation is higher than the machining speed at the time of the machining before the previous lift operation (Yes in step S6), the update unit 16a updates the optimum value matching the electrode material, the workpiece material, the machining area, and the machining condition among the optimum values stored in the storage unit 4a, by the latest accumulated value at the time of the machining before the present lift operation stored in the machining performance storage unit 15a, in order to maximize the machining efficiency (step S7). When a new machining area, machining condition, and accumulated value are input from the updating unit 16a, the storage unit 4a updates and stores the optimum value matching the machining area and the machining condition with the input accumulated value. When the machining speed at the time of the machining before the present lift operation is equal to or lower than the machining speed at the time of the machining before the previous lift operation (No at step S6), the update unit 16a omits the processing at step S7.
The processing from step S8 to step S18 thereafter in the flowchart shown in fig. 8 is the same as the processing from step S8 to step S18 in the flowchart of embodiment 1 shown in fig. 3. In embodiment 2, in the processing of step S11, the comparison unit 5 compares the optimal value and the integrated value for matching the electrode material, the workpiece material, the machining area, and the machining condition in the current electric discharge machining.
The optimum value of the number of discharge pulses during machining varies slightly depending on not only the combination of the electrode material and the workpiece material but also the machining area, the machining conditions, and the like. For example, when the machining area is large, the number of discharge pulses is larger than when the machining area is small. In addition, as for the number of discharge pulses, the larger the machining voltage, the larger the machining current, the larger the number of discharge pulses. Therefore, the optimum value of the number of discharge pulses during machining can be further subdivided by providing information on the machining conditions including the machining voltage and the machining area, for example, as shown in fig. 7. The electric discharge machining apparatus 1a uses the optimum value that is subdivided as compared with the case of embodiment 1, and thereby can control the integrated value, that is, the number of electric discharge pulses during machining with high accuracy.
In the electric discharge machine 1a, when the machining area cannot be grasped in advance in machining of a rectangular shape or the like, the user can directly input the machining area to the electric discharge machine 1a via a machining area input unit not shown. Thus, the electric discharge machine 1a does not need to estimate the machining area, and therefore the number of electric discharge pulses can be secured to an optimum value immediately after the start of machining. In this case, in the electric discharge machine 1a, the processing of step S21 for calculating the machining area is not necessary in the flowchart shown in fig. 8.
As described above, according to the present embodiment, the electric discharge machining apparatus 1a stores the optimum values corresponding to the combination of the electrode material, the workpiece material, the machining area, and the machining conditions, and controls the lifting operation of the electrode 131 using the optimum value based on the current state of electric discharge machining, that is, the optimum value matching the current electric discharge machining state of the electrode material, the workpiece material, the machining area, and the machining conditions. Thus, the electric discharge machining apparatus 1a can control the integrated value, that is, the number of electric discharge pulses during machining with high accuracy by using the optimum value that is subdivided as compared with the case of embodiment 1.
The configuration described in the above embodiment is an example of the content of the present invention, and may be combined with other known techniques, and a part of the configuration may be omitted or modified without departing from the scope of the present invention.
Description of the reference numerals
1. The electric discharge machining device comprises a 1a electric discharge machining device, a 2 material information input part, a 3 machining condition input part, a 4, 4a storage part, a 5 comparison part, a 6 lifting parameter adjustment part, a 7 lifting action control part, an 8 discharge pulse detection part, a 9 discharge pulse number accumulation part, a 10Z-axis motor control part, an 11Z-axis motor, a 12 machining power supply control part, a 13 machining part, a 14 machining speed calculation part, a 15, 15a machining actual result storage part, a 16, 16a updating part, a 17 machining area calculation part, 131 electrodes, 132 machined objects.
Claims (5)
1. An electric discharge machining apparatus comprising:
a material information input unit that receives input of information on an electrode material that is a material of an electrode used for electric discharge machining and information on a workpiece material that is a material of a workpiece to be electric discharge machined;
a machining condition input unit that receives an input of a machining condition for the electric discharge machining;
a discharge pulse detection unit that detects a discharge pulse generated during electric discharge machining;
a discharge pulse number accumulation unit that accumulates the number of discharge pulses and calculates an accumulated value of the discharge pulses per unit time;
a lift action control unit that controls the lift action based on a lift condition of the lift action of the electrode included in the machining condition;
a storage unit that stores an optimum value of the number of discharge pulses per unit time in electric discharge machining that is determined based on a combination of the electrode material and the workpiece material;
a comparison unit that compares the optimal value and the integrated value; and
a lifting parameter adjusting unit that adjusts the lifting condition based on a result of comparison between the optimum value and the integrated value,
the lifting action control part controls the lifting action according to the content adjusted by the lifting parameter adjusting part.
2. The electric discharge machining apparatus according to claim 1, comprising:
a machining speed calculation unit that calculates a machining speed of the electric discharge machining;
a machining actual result storage unit that stores the machining speed and the accumulated value; and
and an updating unit that updates the optimum value stored in the storage unit with an integrated value during the current lifting operation when a machining speed during the current lifting operation is higher than a machining speed during the previous lifting operation.
3. The electric discharge machining apparatus according to claim 1,
a machining area calculation unit for calculating a machining area of the electric discharge machining,
storing an optimum value corresponding to a combination of the electrode material, the workpiece material, the machining condition, and the machining area in the storage unit,
the comparison unit compares the optimal value for matching the electrode material, the workpiece material, the machining condition, and the machining area with the integrated value in the current electric discharge machining,
thereby, an optimum value based on the current state of the electric discharge machining is used.
4. The electric discharge machining apparatus according to any one of claims 1 to 3,
the lifting parameter adjusting unit determines a magnification for adjusting each parameter of the lifting condition based on a ratio of the integrated value to the optimal value.
5. A lifting action control method is characterized by comprising the following steps:
a comparison step in which a comparison unit compares an optimum value of the number of discharge pulses per unit time in electric discharge machining, which is determined by a combination of an electrode material that is a material of an electrode used in electric discharge machining and a workpiece material that is a material of a workpiece to be electric discharge machined, with an integrated value of discharge pulses per unit time, which is obtained by integrating the number of discharge pulses generated in electric discharge machining; and
an adjustment step of adjusting a lifting condition of the lifting operation of the electrode based on a result of comparison between the optimum value and the integrated value,
in the adjusting step, the lift parameter adjusting section,
under the condition that the accumulated value is smaller than the optimal value, the lifting condition is adjusted so that at least 1 of shortening the lifting distance, lengthening the lifting and descending time and reducing the lifting speed is executed in the next lifting action relative to the current lifting action,
when the accumulated value is larger than the optimal value, the lifting condition is adjusted, so that at least 1 of lengthening the lifting distance, shortening the lifting and descending time and increasing the lifting speed is executed in the next lifting action relative to the current lifting action,
and maintaining the setting of the lifting condition of the current lifting action in the next lifting action when the accumulated value is equal to the optimal value.
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| Application Number | Priority Date | Filing Date | Title |
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| PCT/JP2018/015858 WO2019202659A1 (en) | 2018-04-17 | 2018-04-17 | Electrical discharge machining apparatus, and method for controlling jump operation |
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| CN110621431A CN110621431A (en) | 2019-12-27 |
| CN110621431B true CN110621431B (en) | 2020-10-13 |
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| JP (1) | JP6466044B1 (en) |
| CN (1) | CN110621431B (en) |
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| US5267141A (en) * | 1988-10-07 | 1993-11-30 | Mitsubishi Denki K.K. | Machining unit application control apparatus and method employing data from several different operations |
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Also Published As
| Publication number | Publication date |
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| DE112018000099B4 (en) | 2020-08-20 |
| WO2019202659A1 (en) | 2019-10-24 |
| JP6466044B1 (en) | 2019-02-06 |
| CN110621431A (en) | 2019-12-27 |
| JPWO2019202659A1 (en) | 2020-04-30 |
| DE112018000099T5 (en) | 2019-12-24 |
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