WO2011052494A1 - Electrical discharge machining device - Google Patents
Electrical discharge machining device Download PDFInfo
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- WO2011052494A1 WO2011052494A1 PCT/JP2010/068670 JP2010068670W WO2011052494A1 WO 2011052494 A1 WO2011052494 A1 WO 2011052494A1 JP 2010068670 W JP2010068670 W JP 2010068670W WO 2011052494 A1 WO2011052494 A1 WO 2011052494A1
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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
-
- 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
- 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
- B23H1/04—Electrodes specially adapted therefor or their manufacture
-
- 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
Definitions
- the present invention relates to an electrical discharge machining apparatus for performing electrical discharge machining on a machining surface of a workpiece facing an advance end surface of an electrode by discharging between the electrode and the workpiece, and a machining area of the machining surface or an electrode during electrical discharge machining.
- the present invention relates to an electrical discharge machining apparatus capable of accurately calculating an inter-electrode capacitance between machining surfaces and setting appropriate machining conditions.
- an electrode and a workpiece are opposed to each other, and the workpiece is machined into the same shape as the electrode by discharging to an inter-electrode gap between the advance end surface in the machining progress direction of the electrode and the machining surface of the workpiece. It has been broken.
- machining related to machining speed, machining surface roughness, machining shape accuracy, electrode wear, etc. depending on electrical machining conditions such as the peak current value of the discharge current and the discharge pulse width (pulse on time, off time). Characteristics are greatly affected.
- the processing conditions are set based on the processing area.
- the electric discharge machining apparatus described in Patent Document 2 includes capacitance detection means capable of detecting the total capacitance between the electrode and the processed portion of the workpiece (the portion facing the electrode side surface and the electrode lower surface). When the capacitance increases, the voltage polarity is switched. By reducing the applied voltage between the electrodes to decrease the distance between the electrodes and increase the capacitance between the electrodes, the consumption of the electrodes is suppressed and the processing speed is prevented from being lowered.
- a pulse discriminating unit that discriminates between an effective discharge pulse and an ineffective discharge pulse, an advance amount measuring apparatus that measures an advance amount L in the axial direction of the machining process, and the number of discharge pulses
- a division unit that divides n by the advance amount L of unit time, and a machining area calculation unit that calculates a machining area S based on a removal volume v by single discharge and division data n / L are provided.
- the machining area calculation unit calculates the machining area by expressing the machining area by the discharge volume v by single discharge and the divided data n / L and the following expression during the electric discharge machining so that the machining current value is substantially proportional to the machining area.
- the processing conditions have been changed.
- the machining fluid is caused to flow in the gap between the electrode and the workpiece to discharge the machining waste.
- the machining waste becomes difficult to be discharged from the gap as the machining depth increases.
- the electric discharge machining apparatus of Patent Document 3 when the machining waste is accumulated on the machining surface, an effective discharge is generated between the machining waste and the electrode, so that an error between the removal volume v and the number of effective discharge pulses n increases. . Therefore, the machining area error increases as the machining depth increases, and the deviation from the appropriate value of the machining conditions set based on the machining area increases.
- the machining conditions discharge current and discharge pulse
- the machining conditions discharge current and discharge pulse
- it is frequently employed to divide the electrode into a plurality of parts and to process them by a plurality of times of electric discharge machining.
- electric discharge machining since electric discharge machining has to be performed as many times as the number of divided electrodes, there is a problem that the electric discharge machining time for one workpiece is increased and the cost of the electrode is increased. .
- An object of the present invention is to provide an electric discharge machining apparatus capable of accurately calculating a machining area of a machining surface or an inter-electrode capacitance between an electrode advance end surface and a machining surface during electric discharge machining, a moving drive for moving machining scraps and electrodes.
- An electrical discharge machining apparatus capable of setting machining conditions in consideration of backlash and the like in a mechanism, an electrical discharge machining apparatus capable of reducing the number of electrical discharge machinings without causing machining defects, and the like.
- An electric discharge machining apparatus is an electric discharge machining that supplies a machining fluid to a gap between an electrode and a workpiece and applies an electric discharge pulse from the electrode to the workpiece to discharge-process the workpiece.
- a moving means capable of moving the electrode and capable of changing a distance between the electrodes from a forward end surface in the machining progress direction of the electrode to a machining surface of the workpiece, and a moving distance detecting means for detecting the moving distance of the electrode;
- Capacitance measuring means capable of measuring the total capacitance between the processing part of the workpiece and the electrode facing the electrode across the gap, and for each measurement cycle timing after the start of electric discharge machining, In a state where the electric discharge machining is interrupted, the electrode is moved to a plurality of positions by the moving unit, and a plurality of inter-electrode distances detected by the moving distance detecting unit and a plurality of total electrostatic capacitances measured by the capacitance measuring unit.
- the machining condition setting means includes a first machining condition table in which a peak current, a pulse ON time, and a pulse OFF time relating to the electric discharge machining pulse are set in advance using the machining area as a parameter, and the interelectrode capacitance as a parameter.
- a second machining condition table in which the peak current, the pulse ON time, and the pulse OFF time relating to the electric discharge machining pulse are preset.
- the computing means measures the first inter-electrode distance h1 and the first total capacitance C1, which are measured in a state where the electrode is moved to the first movement position, the electrode The second inter-electrode distance h2 and the second total capacitance C2 measured in a state where the electrode is moved to the second movement position, the third inter-electrode distance h3 measured in the state where the electrode is moved to the third movement position, and
- S h1 ⁇ h2 ⁇ h3 (h1 (C2-C3) + h2 (C3-C1) + H3 (C1-C2)) / ( ⁇ (h1-h2) (h2-h3) (h3-h1))
- the processing area is calculated using the formula shown in FIG.
- the computing means measures the first inter-electrode distance h1 and the first total capacitance C1, which are measured in a state where the electrode is moved to the first movement position, the electrode The second inter-electrode distance h2 and the second total capacitance C2 measured in a state where the electrode is moved to the second moving position, and the third inter-electrode distance h3 measured in the state where the electrode is moved to the third moving position.
- the arithmetic means measures the first inter-electrode distance h1 and the first total capacitance C1, which are measured in a state where the electrode is moved to the first movement position, the electrode The second inter-electrode distance h2 and the second total capacitance C2 measured in a state where the electrode is moved to the second movement position, the third inter-electrode distance h3 measured in the state where the electrode is moved to the third movement position, and The third total capacitance C3, the fourth inter-electrode distance h4 measured in a state where the electrode is moved to the fourth movement position, and the fourth total capacitance C4, the angle between the electrode advance end face and the electrode axis
- the processing condition setting means measures the total capacitance between the electrode and the processed part of the workpiece by the capacitance measuring means. The measurement cycle for changing the electric discharge machining condition is changed based on the calculated machining area or the inter-electrode capacitance.
- the machining condition setting means supplies the machining current supplied to the electrodes so as to be substantially proportional to the computed machining area or inter-electrode capacitance. Set.
- the machining condition setting means sets the current density of the machining current to a predetermined current density or less.
- the machining condition setting means includes a discharge pulse setting means for setting a discharge pulse corresponding to the machining current supplied to the electrode and the machining area or the interelectrode capacitance. Yes.
- the machining condition setting means has jump action calculation means for setting at least one of a jump period and a jump amount of the jump action based on the error distance ⁇ of the distance between the poles.
- the moving means capable of moving the electrode, the moving distance detecting means for detecting the moving distance of the electrode, and the capacitance measurement capable of measuring the total capacitance between the electrode and the processed part of the workpiece.
- the machining area or the inter-electrode capacitance is calculated using the inter-electrode distance at a plurality of positions where the electrode is moved and the total capacitance between the electrode and the machining part of the workpiece, Capacitance between the electrodes in proportion to the area can be calculated with high accuracy, based on the machining area obtained in a state where the electric discharge machining after the electric discharge machining is interrupted or the calculated value of the capacitance between the electrodes with high accuracy,
- the machining conditions related to the electric discharge machining pulse can be appropriately set in accordance with the inter-electrode state such as the change of the machining area and the generation of machining scraps.
- the electric discharge machining condition setting means sets the peak current of the electric discharge machining pulse, the pulse ON time, and the pulse OFF time based on the first and second machining condition tables. be able to. According to the configuration of (3), even when the distance from the surface of the workpiece to the processing surface is unknown, the processing load for calculating the processing area can be reduced, so that the processing speed is high. Accurate machining area can be calculated.
- the machining area and error distance can be computed.
- the error distance it is possible to set processing conditions that take into account processing scraps, backlash, and the like.
- the configuration of (5) even if the distance from the surface of the workpiece to the machining surface is unknown, the capacitance between the electrode advance end formed in a complicated shape and the machining surface is Therefore, it is possible to calculate the capacitance between the electrodes and the error distance that are exactly proportional to the processing area.
- the error distance it is possible to set processing conditions that take into account processing scraps, backlash, and the like.
- the measurement cycle for changing the electric discharge machining conditions by measuring the total capacitance between the electrode and the machining portion of the workpiece by the capacitance calculating means is set as the machining area or the inter-electrode static. Since the change is made based on the electric capacity, the measurement cycle can be set so as to follow the shape change of the electrode advance end face, and appropriate electric discharge machining conditions can be set.
- the processing current value supplied to the electrodes is controlled so as to be approximately proportional to the processing area or the inter-electrode capacitance calculated by the processing condition setting means. It is possible to prevent abnormal wear of the electrode.
- the machining condition setting unit controls the current density to be equal to or lower than the predetermined current density, so that it is possible to prevent the occurrence of problems such as a reduction in machining speed.
- the discharge pulse corresponding to the machining current value to be supplied to the electrode and the machining area or the inter-electrode capacitance can be set by the discharge pulse setting means.
- the jump operation calculating means for setting at least one of the jump period and the jump amount of the jump operation based on the error distance of the distance between the poles is provided, the machining waste generated by the machining is removed from the machining surface It can be reliably excluded from the top, and a reduction in processing speed can be prevented.
- FIG. 1 is an overall view of an electric discharge machining apparatus according to Embodiment 1 of the present invention. It is a block diagram of an electric discharge machining apparatus. It is a circuit diagram which shows an electrostatic capacitance measurement part. It is explanatory drawing explaining the voltage of the capacitor between an electrode and the process surface of a to-be-processed object.
- (A), (b) is a figure explaining the item for processing area calculation, respectively.
- (A), (b) is a figure explaining the detection procedure of the dielectric constant of a processing liquid.
- (A), (b) is a figure explaining the item for a capacitance calculation between electrodes, respectively. It is a diagram which shows a jump period map. It is a diagram which shows a jump amount map.
- the electrical discharge machining apparatus M supplies a machining liquid to a gap between the electrode E and the workpiece W, applies a discharge pulse from the electrode E to the workpiece W, and then processes the workpiece W.
- This electric discharge machining apparatus M includes peripheral devices such as a machining machine body 1, a control device 2, and a machining liquid tank 7.
- the processing machine main body 1 includes a head 3 equipped with an electrode E, a Z-axis moving mechanism 4 (moving means) as a feeding device capable of reciprocating the head 3 in the vertical direction (Z-axis), and a workpiece W.
- the X-axis moving mechanism 5 capable of reciprocating horizontally in the horizontal direction (X axis) of FIG. 1 and the machining liquid tank 7 horizontally in the front-rear direction (Y axis) perpendicular to the horizontal direction
- a Y-axis moving mechanism 6 that can reciprocate, a machining liquid tank 7 that can store a workpiece W and can store a machining liquid, a base 8, a cable 25, and the like.
- the electrode E is mounted on a mounting plate that is detachably mounted on the lower end of the head 3.
- the Z-axis moving mechanism 4 includes a pair of Z-axis feed guides, a ball screw mechanism, a Z-axis motor, and the like that are provided on the base 8 and extend along the Z-axis direction, and are numerically controlled by the control device 2.
- the head 3 is driven to move in the Z-axis direction by driving the Z-axis motor.
- the X-axis moving mechanism 5 includes an X-axis movable base, a pair of X-axis feed guides, a ball screw mechanism, an X-axis motor, and the like that are provided on the base 8 and extend along the X-axis direction.
- the X-axis movable table is driven to move in the X-axis direction by driving the numerically controlled X-axis motor.
- the Y-axis moving mechanism 6 includes a Y-axis movable base, a pair of Y-axis feed guides that are provided on the X-axis movable base and extend along the Y-axis direction, a ball screw mechanism, a Y-axis motor, and the like.
- the Y-axis movable table and the machining liquid tank 7 are driven to move in the Y-axis direction by driving a Y-axis motor that is numerically controlled by the control device 2.
- the machining liquid tank 7 is fixed to the upper end of the Y-axis movable base of the Y-axis moving mechanism 6.
- the control device 2 is installed adjacent to the processing machine main body 1 and supplies power and a control signal to the processing machine main body 1 via the cable 25.
- the electrode E and the workpiece W are configured to be relatively movable in the X and Y axis directions parallel to the Z axis direction.
- the Z-axis moving mechanism 4 can change the position of the electrode E in the Z-axis direction by moving the head 3 in the Z-axis direction, and can extend from the advance end surface of the electrode E in the machining progress direction to the machining surface of the workpiece W.
- the distance between the poles can be changed.
- the surface portion of the workpiece W that faces the forward end surface in the machining progress direction of the electrode E is defined as the machining surface of the workpiece W, and the area of the machining surface is defined as the machining area.
- the electrode E is made of copper or graphite, but may be made of copper tungsten when the workpiece W is a cemented carbide.
- the control device 2 is composed of a computer including a CPU, a ROM, a RAM, an interface, and the like. And a discharge detector 11 for detecting a discharge state generated between the electrode E and the workpiece W, and a static region between the electrode E and the machining portion of the workpiece W facing the side and bottom surfaces of the electrode E with a gap therebetween.
- Capacitance measurement unit 12 that measures electric capacity (hereinafter referred to as total capacitance)
- discharge control unit 13 that supplies a discharge pulse for electric discharge machining to electrode E and workpiece W, and machining current measurement And a calculation mode selector switch 15 and the like.
- the following description is given by setting the electrostatic capacitance between the advance end face of the electrode E and the work surface of the workpiece W facing the advance end face as an interelectrode capacitance.
- the capacitance measuring unit 12 is connected to the switching transistor 12s interposed in the power supply line from the power source Vc, the constant current circuit 12a connected to the power supply line, and the power supply line. Then, a pulse output circuit 12b capable of outputting a pulse having a constant cycle (pulse ON time and OFF OFF time are equal), a transistor 12c, a resistor 12d, a voltage detection circuit 12e, and the like are provided.
- the base side terminal 12x of the transistor 12s and the output terminal 12v of the voltage detection circuit 12e are connected to the capacitance measurement control unit 17.
- the transistor 12s is turned on by the drive signal from the capacitance measurement control unit 17, and the capacitance measurement unit 12 is operated.
- the output signal from the output terminal 12v of the voltage detection circuit 12e is processed by the capacitance measurement control unit 17 so that the total capacitance is measured. That is, the capacitance measuring unit 12 and the capacitance measuring control unit 17 correspond to “capacitance measuring unit”.
- the capacitor 12f is configured through the gap between them and the processing liquid in the gap.
- a direct current i is periodically supplied from the pulse output circuit 12b to the machining part of the electrode E and the workpiece W (the part facing the electrode side surface and the electrode advance end face), and the voltage detection circuit. 12e is used to detect the voltage V of the electrode E, and based on the average voltage Vm calculated from the voltage V in the capacitance measurement control unit 17, the direct current i, and the time to supply the direct current i to the capacitor 12f. Then, the total capacitance is calculated.
- the capacitance measurement control unit 17 receives the voltage signal of the detection voltage V supplied from the output terminal 12v, performs A / D conversion, and calculates the average voltage Vm.
- the capacitance measuring unit 12 is not limited to the above-described configuration, and may have various configurations as long as it can measure at least the total capacitance C between the electrode E and the processed portion of the workpiece W. It can be adopted.
- the discharge control unit 13 is supplied with power from the power supply circuit 10 and applies a discharge pulse set in a processing condition setting unit 19 described later to the electrode E and the workpiece W.
- the machining current measuring unit 14 measures the current supplied by the discharge pulse through the ammeter 14 a and supplies the detected current to the arithmetic processing unit 9.
- the calculation mode changeover switch 15 sets the machining conditions based on the machining area calculation mode in which the machining conditions are set based on the machining area of the machining surface and the machining capacity based on the interelectrode capacitance in the arithmetic processing unit 9 before the electric discharge machining process is started.
- the electrostatic capacity calculation mode to be selected can be selectively set.
- the calculation mode change-over switch 15 may be omitted, and the machining area of the machining surface may be calculated first, and the inter-electrode capacitance may be automatically calculated when the machining area is difficult to calculate.
- the arithmetic processing unit 9 includes a position control unit 16 (movement distance detecting unit) that controls the Z-axis moving mechanism 4, a capacitance measurement control unit 17, a calculation unit 18, and a processing condition setting unit 19 (processing condition setting unit). ) And the X, Y control unit 20 and the like.
- the position control unit 16 is formed so that the distance between the electrodes from the advance end surface of the electrode E to the machining surface can be changed by driving the head 3 up and down by the Z-axis moving mechanism 4.
- the position control unit 16 is formed so as to be able to detect an inter-electrode distance from the forward end surface of the electrode E to the machining surface.
- the capacitance measurement control unit 17 receives a measurement cycle signal for measuring the total capacitance by the capacitance measurement unit 12 from the measurement cycle calculation unit 24 described later, and performs the measurement cycle.
- the operation timing of the capacitance measuring unit 12 is controlled by turning on the transistor 12s.
- This electric discharge machining apparatus M uses a machining program for each workpiece and analyzes the machining program with a numerical control program, while the Z-axis moving mechanism 4 is moved by the position controller 16 in the same manner as a general electric discharge machining apparatus.
- the X and Y control unit 20 controls driving of the X-axis moving mechanism 5 and the Y-axis moving mechanism 6 as described above.
- the computing means 18 includes a machining area computing unit 21 that computes the machining area when in the machining area computing mode, and a capacitance computing unit 22 that computes the inter-electrode capacitance when in the capacitance computing mode. As shown in FIG.
- the machining area calculation unit 21 moves the electrode E to a plurality of different positions in the vertical direction by the Z-axis moving mechanism 4 during the electric discharge machining (intermediate time of the electric discharge machining), and the position control unit 16 First and second inter-electrode distances h1 and h2 at the first and second moving positions d1 and d2 (distances from the surface of the workpiece W to the electrode advancement end surface), which are a plurality of different positions in the detected vertical direction, Using the first and second total capacitances C1 and C2 at two positions corresponding to the first and second inter-electrode distances h1 and h2 measured by the capacitance measurement unit 12 and the capacitance measurement control unit 17, It is formed so as to calculate the processing area S of the processing surface Wf of the workpiece W.
- a columnar electrode having a substantially horizontal advance end face Ef will be described as the electrode E.
- the electrode E does not necessarily have a columnar shape and is processed according to the progress of electric discharge machining. It may be an electrode whose area changes continuously or discontinuously.
- the electrode E is brought into contact with the processing surface Wf of the workpiece W to initialize the distance between the electrodes to zero.
- the Z-axis movement mechanism 4 is driven and controlled, and the electrode E is moved to the first movement position d1.
- the first total capacitance C1 the interelectrode capacitance Cp1 between the electrode advance end surface Ef and the processing surface Wf, the processing area S of the processing surface Wf, the first interelectrode distance h1, the side surface Es of the electrode E and the surface to be covered.
- the first total capacitance C1 can be expressed by the following equation (1) and is detected by measurement.
- C1 Cp1 + Ca (1)
- Cp1 ⁇ S / h1.
- the Z-axis moving mechanism 4 is driven and controlled, and the electrode E is moved to the second moving position d2.
- the second total capacitance C2 the interelectrode capacitance Cp2 between the electrode advance end surface Ef and the machining surface Wf, and the second interelectrode distance h2 from the electrode advance end surface Ef to the machining surface Wf
- the second total The capacitance C2 can be expressed by the following equation (2) and is detected by measurement.
- C2 Cp2 + Ca ⁇ d2 / d1 (2)
- Cp2 ⁇ S / h2.
- the machining area S can be expressed by the following formula (3).
- S (h1 ⁇ h2 (C2 ⁇ d1 ⁇ C1 ⁇ d2)) / ( ⁇ (d1 ⁇ h1 ⁇ d2 ⁇ h2)) ...
- the distances d1 and d2 from the surface of the workpiece W to the electrode advance end surface are known in the position control unit 16 because the distance from the surface of the workpiece W to the machining surface Wf is known. It can be calculated using the distances h1 and h2 and the dielectric constant ⁇ .
- the dielectric constant ⁇ of the working fluid is obtained using a standard electrode Ea whose working area is known.
- the standard electrode Ea is brought into contact with the surface of the workpiece W to initialize the distance between the electrodes Ea to zero.
- the standard electrode Ea is moved from the surface of the workpiece W to a position at a distance h0, and the total capacitance C0 at this position is compared with the capacitance measuring unit 12 and the electrostatic capacitance. Measurement is performed by the capacity measurement control unit 17.
- the dielectric constant ⁇ can be expressed by the following equation (4).
- ⁇ h0 ⁇ C0 / S0 (4)
- the processing area S of the processing surface Wf of the workpiece W is calculated.
- the first and second inter-electrode capacitances Cp1 and Cp2 using the calculated value of the processing area S, it is possible to detect the presence / absence of processing waste or the like from the increase / decrease tendency of the inter-electrode capacitance. .
- the electrostatic capacity calculation unit 22 moves the electrode E to a plurality of different positions in the vertical direction by the Z-axis moving mechanism 4 during the electric discharge machining, and detects a plurality of positions detected by the position control unit 16, for example, first and second.
- the inter-electrode capacitance between the forward end face Ef of the electrode EA and the processing surface Wf of the workpiece W is calculated using the first and second total capacitances C21 and C22 at the two positions. Yes.
- the electrode EA has, for example, a column shape having an angle ⁇ (0 ° ⁇ ⁇ 90 °) between the electrode advance end surface Ef and the electrode axis, and distances d21 and d22 from the surface of the workpiece W to the processing surface. Is known in the position controller 16. *
- the electrode EA is brought into contact with the processing surface of the workpiece W to initialize the distance between the electrodes to zero.
- the Z-axis moving mechanism 4 is driven and controlled to move the electrode EA to the first moving position d21.
- the first total capacitance C21, the interelectrode capacitance Cp21 between the electrode advance end surface and the processing surface, the processing area SA, the first interelectrode distance h21 from the advance end surface of the electrode EA to the processing surface, and the electrode EA Assuming that the capacitance Ca between the side surface and the workpiece W, the dielectric constant ⁇ of the working fluid, and the angle ⁇ of the electrode advance end surface with respect to the vertical surface, the first total capacitance C21 can be expressed in the same manner as the above equation (1). Can be detected by measurement.
- the first total capacitance C21 can be expressed by the following equation (6).
- Cp21 ⁇ SA / (h21 ⁇ sin ⁇ ) (5)
- C21 ⁇ SA / (h21 ⁇ sin ⁇ ) + Ca (6)
- the head 3 is moved upward by the Z-axis moving mechanism 4 to move the electrode EA to the second movement position d22.
- the second total capacitance C22 can be expressed in the same manner as the above formula (2).
- the second total capacitance C22 can be expressed by the following equation (8) and detected by measurement.
- Cp22 ⁇ SA / (h22 ⁇ sin ⁇ ) (7)
- C22 ⁇ SA / (h22 ⁇ sin ⁇ ) + Ca ⁇ d22 / d21 (8)
- the machining area SA can be expressed by the following formula (9).
- SA (h21 ⁇ h22 (C22 ⁇ d21-C21 ⁇ d22)) ⁇ sin ⁇ / ( ⁇ (d21 ⁇ h21 ⁇ d22 ⁇ h22)) (9)
- the interelectrode capacitance Cp21 at the first movement position d21 can be expressed by the following equation (10).
- Cp21 h22 (C22 ⁇ d21 ⁇ C21 ⁇ d22) / (d21 ⁇ h21 ⁇ d22 ⁇ h22) (10)
- the inter-electrode capacitance Cp22 at the second movement position d22 can be expressed by the following equation (11).
- Cp22 h21 (C22 ⁇ d21 ⁇ C21 ⁇ d22) / (d21 ⁇ h21 ⁇ d22 ⁇ h22) (11)
- ⁇ can be used to calculate the first and second inter-electrode capacitances Cp21 and Cp22.
- the interelectrode capacitances Cp21 and Cp22 are physical quantities proportional to the processing area SA, for example, the interelectrode distance h21 is set as a target interelectrode distance, and processing is performed based on the interelectrode capacitance Cp22.
- the condition setting unit 19 sets electric discharge machining conditions as will be described later. Further, similarly to the above, it is possible to detect the inter-electrode state such as the generation state of the machining waste from the increasing / decreasing tendency of at least one of the first and second inter-electrode capacitances Cp21 and Cp22. Note that the electrode EA shown in FIG. 7 has been described by taking a columnar electrode as an example.
- the electrode does not necessarily have a columnar shape, and the machining area may be continuous or not as the electric discharge machining progresses.
- An electrode that changes continuously may be used.
- the electrode may have a plurality of inclined surfaces having the same inclination angle or different inclination angles to the forward end face of the electrode.
- the machining condition setting unit 19 includes a discharge pulse setting unit 23, a measurement cycle calculation unit 24, and a jump operation calculation unit 25.
- the discharge pulse setting unit 23 includes a machining condition table shown in Table 1 and a machining condition table shown in Table 2.
- the machining condition setting unit 19 applies the machining area S obtained by calculation as described above to the machining condition table shown in Table 1 to thereby increase the discharge pulse peak.
- the peak current is set to a value substantially proportional to the processing area S. Further, the current density is a value of 5 A / cm 2 or less and is set to about 5 A / cm 2 .
- the voltage of the discharge pulse is appropriately set by the discharge control unit 13. Then, the electrical discharge machining condition data set as described above is supplied to the electrical discharge control unit 13, and electrical discharge machining is executed based on the electrical discharge pulse.
- the machining condition setting unit 19 adds the first and second inter-electrode capacitances Cp21, obtained by calculation as described above to the machining condition table shown in Table 2.
- the peak current of the discharge pulse and the ON time and OFF time of the discharge pulse are set by applying the first inter-electrode capacitance Cp21 of Cp22.
- the peak current is set to a value substantially proportional to the interelectrode capacitance.
- the current density is a value of 25 A / nF or less and is set to about 25 A / nF.
- the electrical discharge machining condition data set as described above is supplied to the electrical discharge control unit 13, and electrical discharge machining is executed based on the electrical discharge pulse.
- the processing condition tables shown in Tables 1 and 2 are merely examples, and can be appropriately changed depending on the dielectric constant of the processing liquid, the combination of the material of the electrode and the material of the workpiece, or the processing conditions.
- the measurement cycle calculation unit 24 has a map in which the measurement cycle for measuring the total capacitance and changing the processing conditions is set in advance by the capacitance measurement unit 12 and the capacitance measurement control unit 17.
- the measurement cycle is set using the processing areas S and SA (or the capacitance between the electrode advance end face and the processing surface) as a parameter. Since the advance speed of the electrode is larger as the processing areas S and SA are smaller, the above map is set so that the measurement period is increased as the processing areas S and SA (or the above-described interelectrode capacitance) are increased. ing.
- the jump operation calculation unit 25 is configured to set the jump period and the jump amount of the jump operation of the electrodes E and EA based on the error distance ⁇ of the distance between the electrodes.
- the electrode jumping operation is an operation of moving the electrode up and down in order to cause the machining waste accumulated on the processing surface to flow and to be discharged out of the gap. As shown in FIGS. 8 and 9, the relationship between the error distance ⁇ as the height of the machining waste accumulated on the processing surface of the workpiece W, the jump cycle, and the jump movement amount is previously stored in the form of a map or a table. Set and stored in memory.
- the processing area and the capacitance between the poles are calculated as shown in FIGS.
- a default error distance for example, 4 ⁇ m
- the map of FIG. 8 is set so that the jump cycle decreases as the error distance ⁇ increases
- the map of FIG. 9 is set so that the jump movement amount increases as the error distance ⁇ increases.
- the maps shown in FIGS. 8 and 9 are merely examples, and can be changed as appropriate depending on the machining shape, machining conditions, and the like.
- the electric discharge machining condition setting process is a process performed in the machining area calculation mode for the example shown in FIG.
- various signals such as the dielectric constant ⁇ of the machining fluid and the type of the selected operation mode are read (S1).
- S2 it is determined whether or not the start switch of the electric discharge machining process has been turned on. If the electric discharge machining process is started as a result of the determination in S2, the process proceeds to S3, and it is determined whether or not the dielectric constant data of the machining liquid is held. As a result of the determination in S2, if the electric discharge machining process is not started, the process returns to S1.
- the process proceeds to S4 and the inter-electrode distance and the total capacitance are measured.
- the process proceeds to S5, and after detecting the dielectric constant ⁇ of the working fluid using the standard electrode as described above, the process proceeds to S4.
- the position controller 16 and the Z-axis moving mechanism 4 sequentially drive the electrode advance end face to the first and second moving positions, and the first and second inter-electrode distances h1 and h2 and the work piece at the respective moving positions.
- the distances d1 and d2 from the surface of W to the processed surface are measured.
- the first and second total capacitances C1 and C2 at the first and second movement positions are measured by the capacitance measurement unit 12 and the capacitance measurement control unit 17.
- S6 it is determined whether the machining area calculation mode is selected. If the machining area calculation mode is selected as a result of the determination in S6, a machining area calculation process is performed in S7.
- the machining area calculating unit 21 substitutes the first and second total capacitances C1 and C2, the first and second inter-electrode distances h1 and h2, and the distances d1 and d2 into the expression (3). S is calculated. After calculating the machining area, the process proceeds to S9.
- machining conditions are set using the machining condition table of Table 1 based on the calculated machining area.
- the machining conditions set here include electrical conditions for electric discharge machining such as a peak current value, a jump period of the electrode E, a jump movement amount, and the like. After setting the machining conditions, the process proceeds to S10 and the electric discharge machining process is started.
- the measurement cycle for measuring the total capacitance is calculated by the capacitance measurement control unit 17.
- the process After starting the electrical discharge machining process, it is determined whether or not it is the measurement cycle timing (S11). As a result of the determination in S11, in the case of the measurement cycle timing, the process proceeds to S4, and the distance between the electrodes and the total capacitance are measured in a state where the electric discharge machining process is interrupted. As a result of the determination in S11, if it is not the measurement cycle timing, the process proceeds to S12 to determine the end of the electric discharge machining process. If the electrical discharge machining process is completed as a result of the determination in S12, the present control is terminated. If the electrical discharge machining process is not completed, the process proceeds to S10 and the electrical discharge machining process is continued.
- the electric discharge machining condition setting process executed in the capacitance calculation mode is substantially the same as described above. If the electrostatic capacity calculation mode is selected as a result of the determination in S6, the process proceeds to S8 to perform the electrostatic capacity calculation process.
- the capacitance calculator 22 calculates the first and second total capacitances C1 and C2, the first and second inter-electrode distances h1 and h2, and the distances d1 and d2 with respect to the equation (10) or the equation (11). By substituting, calculation is performed for at least one of the first and second inter-electrode capacitances Cp1, Cp2.
- the first inter-electrode distance h1 is a target inter-electrode distance.
- the process proceeds to S9, and the processing conditions are set using the processing condition table of Table 2 based on the calculated inter-electrode capacitance. After setting the machining conditions, the process proceeds to S10 and the electric discharge machining process is started.
- the processing area S of the processed surface of the workpiece W can be obtained with high accuracy. Further, even if it is difficult to calculate the machining area SA because the electrode advance end face has a complicated shape, the first inter-electrode capacitance Cp21 or the second inter-electrode capacitance Cp22 that is approximately proportional to the machining area SA is obtained. As with the above, it can be obtained with high accuracy.
- the electrical discharge machining conditions based on the highly accurate calculation value of the machining area S (or SA) or the capacitance between the first and second electrodes Cp1, Cp2 (or Cp21, Cp22). it can.
- the first and second inter-electrode distances h1, h2 (or h21, h22) between the electrode advance end face and the machining surface are used for the calculation, the first and second inter-electrode capacitances Cp1, Cp2 (or With respect to the values of Cp21 and Cp22), it is possible to reflect the height of the machining waste accumulated on the machining surface as an error distance, and it is possible to set appropriate machining conditions.
- the machining condition setting unit 19 is provided for setting machining conditions for electric discharge machining based on the calculated machining areas S and SA or the first and second inter-electrode capacitances Cp21 and Cp22 instead of the machining area SA, Appropriate measurement cycle, electrical conditions for electrical discharge machining, jump cycle of jump operation, jump movement amount, etc. can be set appropriately according to the size of the machining area and the inter-electrode state based on the capacitance between the electrodes. it can.
- the machining area calculation unit 21 calculates the machining area S based on the equation (3), it is possible to reduce the control load for the calculation and to increase the calculation processing speed of the machining area. Since the capacitance calculation unit 22 calculates the interelectrode capacitances Cp21 and Cp22 based on the equations (9) to (11), even if the electrode advance end face has a complicated shape, it is proportional to the machining area SA. The interelectrode capacitances Cp21 and Cp22 can be accurately calculated.
- the processing condition setting unit 19 changes the measurement cycle based on the processing areas S and SA (or the first and second inter-electrode capacitances Cp21 and Cp22 instead of the processing area SA), Electrical conditions can be changed and set at a measurement cycle suitable for shape change, and appropriate machining conditions can be set.
- the processing condition setting unit 19 controls the processing current value supplied to the electrodes E and EA so as to be substantially proportional to the processing areas S and SA or the first and second inter-electrode capacitances Cp21 and Cp22 instead of the processing area SA. Therefore, abnormal wear of the electrodes E and EA due to excessive supply of current can be prevented. Since the supply current to the electrodes E and EA is set to be equal to or lower than a predetermined current density, it is possible to prevent the occurrence of problems such as a reduction in processing speed.
- Example 2 will be described with reference to FIG.
- the difference from the first embodiment is that the distance D from the surface of the workpiece W to the processing surface is known in the first embodiment, whereas the distance D is unknown in the second embodiment.
- the column-shaped electrode EB is brought into contact with the processed surface of the workpiece W to initialize the movement position (distance between the electrodes) of the electrode EB.
- the electrode EB is moved upward by the Z-axis moving mechanism 4 to move the electrode EB to the first movement position.
- the first total capacitance C31 the interelectrode capacitance Cp31 between the electrode advance end surface and the processing surface, the processing area SB, the first interelectrode distance h31 from the electrode advance end surface to the processing surface, and the side surface of the electrode EB
- the capacitance Ca with the workpiece W, the dielectric constant ⁇ of the machining fluid, and the distance D from the surface of the workpiece W to the machining surface the first total capacitance C31 is expressed by the following equation (12). Can be detected by measurement.
- C31 Cp31 + Ca (D ⁇ h31) / D (12)
- the interelectrode capacitance Cp31 ⁇ SB / h31.
- the Z-axis moving mechanism 4 drives the electrode EB to move further upward from the first movement position, and moves the electrode EB to the second movement position.
- the second total capacitance C32 Cp32 + Ca (D ⁇ h32) / D (13)
- the interelectrode capacitance Cp32 ⁇ SB / h32.
- the Z-axis moving mechanism 4 drives the electrode EB to move further upward from the second movement position, and moves the electrode EB to the third movement position.
- the third total capacitance C33 Cp33 + Ca (D ⁇ h33) / D (14)
- the interelectrode capacitance Cp33 ⁇ SB / h33.
- the machining area SB can be expressed by the following equation (15).
- SB h31 ⁇ h32 ⁇ h33 (h31 (C32 – C33) + h32 (C33 – C31) + H33 (C31-C32)) / ( ⁇ (h31-h32) (h32-h33) (h33-h31)) ...
- the machining area calculation unit 21 calculates the inter-electrode capacitances Cp31, Cp32, Cp33 and the distance D from the surface of the workpiece W to the machining surface based on the calculated machining area SB.
- the discharge pulse setting unit 23 calculates a current density using the machining current value detected by the machining current measurement unit 14 and the machining area SB, and controls the current density to be equal to or lower than a predetermined current density.
- the machining condition setting unit 19 sets electrical machining conditions such as discharge pulses by applying the machining area SB to the machining condition table shown in Table 1.
- Example 2 There are basically the same operations and effects as in the first embodiment.
- appropriate processing conditions can be obtained by detecting the interelectrode distances h31 to h33 and the total capacitances C31 to C33 at the first to third movement positions. Can be set.
- the electrode EB shown in FIG. 11 has been described by taking a columnar electrode as an example. However, the electrode EB does not necessarily have a columnar shape, and the machining area continuously or discontinuously according to the progress of electric discharge machining. The electrode may change to
- Example 3 will be described with reference to FIG.
- the difference from the first embodiment is that, in the first embodiment, the distance D from the surface of the workpiece W to the processing surface is known, whereas in the third embodiment, the distance D is unknown and the measured pole This is a point that includes the error distance ⁇ in the distance between them.
- the error distance ⁇ is caused by processing debris accumulated on the processing surface of the workpiece W, the backlash of the gear system of the Z-axis moving mechanism 4, and the like, and is positive when no backlash occurs. It represents the amount of accumulated work scraps on the work surface. When backlash occurs, it represents the sum of the amount of backlash as a negative value and the amount of work scrap accumulated as a positive value.
- the columnar electrode EC is brought into contact with the processing surface of the workpiece W to initialize the movement position (distance between the electrodes) of the electrode EC.
- the electrode EC is moved upward by the Z-axis moving mechanism 4 to move the electrode EC to the first movement position.
- the first total capacitance C41 the interelectrode capacitance Cp41 between the electrode advance end surface and the processing surface, the processing area SC, the first interelectrode distance h41 from the electrode advance end surface to the processing surface, and the side surface of the electrode EC
- the capacitance Ca with the workpiece W, the dielectric constant ⁇ of the machining fluid, the distance D from the surface of the workpiece W to the machining surface, and the error distance ⁇ the first total capacitance C41 is expressed by the following equation (16 ) And can be detected by measurement.
- C41 Cp41 + Ca (D ⁇ h41 ⁇ ) / D (16)
- the interelectrode capacitance Cp41 ⁇ SC / (h41 + ⁇ ).
- the electrode EC is further moved upward from the first movement position by the Z-axis movement mechanism 4 to move the electrode EC to the second movement position.
- the second total capacitance C42 Cp42 + Ca (D ⁇ h42 ⁇ ) / D (17)
- the interelectrode capacitance Cp42 ⁇ SC / (h42 + ⁇ ).
- the electrode EC is further moved upward from the second movement position by the Z-axis movement mechanism 4 to move the electrode EC to the third movement position.
- the third total capacitance C43 Cp43 + Ca (D ⁇ h43 ⁇ ) / D (18)
- the interelectrode capacitance Cp43 ⁇ SC / (h43 + ⁇ ).
- the electrode EC is moved further upward from the third movement position by the Z-axis movement mechanism 4, and the electrode E is moved to the fourth movement position.
- the fourth total capacitance C44 Cp44 + Ca (D ⁇ h44 ⁇ ) / D (19)
- the interelectrode capacitance Cp44 ⁇ S / (h44 + ⁇ ).
- the machining area SC can be expressed by the following equation (20) including the error distance ⁇ .
- SC ((h41 + ⁇ ) ⁇ (h42 + ⁇ ) ⁇ (h43 + ⁇ ) ⁇ (h41 (C42 ⁇ C43) + h42 (C43 ⁇ C41) + h43 (C41 ⁇ C42))) / ( ⁇ (h41 ⁇ h42) ⁇ (h41 ⁇ h43) ⁇ (h43-h42)).
- the jump operation calculation unit 25 sets the jump period of the electrode EC to be shorter as the error distance ⁇ is larger, and sets the movement amount by the jump to be larger as the error distance ⁇ is larger. ing.
- the error distance ⁇ is corrected with the amount of backlash, thereby accurately calculating the amount of accumulated machining waste deposited on the machining surface. can do.
- the machining area SC is determined by detecting the inter-electrode distances h41 to h44 and the total capacitances C41 to C44 at the first to fourth movement positions. It is possible to calculate accurately and set appropriate machining conditions. In addition, by calculating the error distance ⁇ , the machining area SC can be accurately calculated in consideration of machining scraps, backlash, and the like, and the machining conditions can be set appropriately.
- the electrode EC shown in FIG. 12 has been described by taking a columnar electrode as an example, the electrode does not necessarily have a columnar shape, and the machining area changes continuously or discontinuously according to the progress of electric discharge machining. It may be an electrode.
- Example 4 will be described with reference to FIG.
- the difference from the first embodiment is that the distance D from the surface of the workpiece W to the processing surface is known in the first embodiment, whereas the distance D is unknown in the fourth embodiment, and the measured distance between the electrodes
- the distance includes the error distance ⁇ and the electrode advance end face has a complicated shape.
- a column-shaped electrode ED having an angle ⁇ (0 ° ⁇ ⁇ 90 °) between the electrode advance end surface and the electrode axis (vertical surface) is brought into contact with the processing surface of the workpiece W to move the electrode ED ( Initialize the distance between the poles.
- the electrode ED is moved and driven upward by the Z-axis moving mechanism 4 to move the electrode ED to the first movement position.
- the first total capacitance C51, the interelectrode capacitance Cp51 between the electrode advance end surface and the processing surface, the processing area SD, the first interelectrode distance h51 from the electrode advance end surface to the processing surface, and the side surface of the electrode ED When the capacitance Ca with the workpiece W, the dielectric constant ⁇ of the machining fluid, the distance D from the surface of the workpiece W to the machining surface, the error distance ⁇ , and the angle ⁇ between the electrode advance end surface and the electrode,
- One total capacitance C51 can be expressed by the following equation (22) and is detected by measurement.
- the electrode ED is further moved upward from the first movement position by the Z-axis movement mechanism 4 to move the electrode ED to the second movement position.
- the second total capacitance C52, the interelectrode capacitance Cp52 between the electrode advance end surface and the machining surface, and the second interelectrode distance h52 from the electrode advance end surface to the machining surface can be expressed by the following equation (23) and is detected by measurement.
- the electrode ED is further moved upward from the second movement position by the Z-axis movement mechanism 4 to move the electrode ED to the third movement position.
- the third total capacitance C53, the interelectrode capacitance Cp53 between the electrode advance end surface and the machining surface, and the third interelectrode distance h53 from the electrode advance end surface to the machining surface Can be expressed by the following equation (24) and is detected by measurement.
- C53 ⁇ SD / ((h53 + ⁇ ) sin ⁇ ) + Ca (D ⁇ h53 ⁇ ) / D (24)
- the interelectrode capacitance Cp53 ⁇ SD / ((h53 + ⁇ ) sin ⁇ ).
- the Z-axis moving mechanism 4 drives the electrode ED to move further upward from the third movement position, and moves the electrode ED to the fourth movement position.
- the fourth total capacitance C54, the interelectrode capacitance Cp54 between the electrode advance end surface and the machining surface, and the fourth interelectrode distance h54 from the electrode advance end surface to the machining surface the fourth total capacitance C54. Can be expressed by the following equation (25) and is detected by measurement.
- C54 ⁇ SD / ((h54 + ⁇ ) sin ⁇ ) + Ca (D ⁇ h54 ⁇ ) / D (25)
- the interelectrode capacitance Cp54 ⁇ SD / ((h54 + ⁇ ) sin ⁇ ).
- the machining area SD can be expressed by the following equation (26) including the error distance ⁇ .
- SD ((h51 + ⁇ ) ⁇ (h52 + ⁇ ) ⁇ (h53 + ⁇ ) ⁇ (h51 (C52 ⁇ C53) + H52 (C53 ⁇ C51) + h53 (C51 ⁇ C52)) ⁇ sin ⁇ ) / ( ⁇ (h51 ⁇ h52) ⁇ (h52 ⁇ h53) ⁇ (h53 ⁇ h51))
- the error distance ⁇ can be obtained by solving the equations (22) to (25) for the error distance ⁇ .
- the interelectrode capacitance Cp51 at the first movement position d51 can be expressed by the following equation (27).
- Cp51 ((h52 + ⁇ ) ⁇ (h53 + ⁇ ) ⁇ (h51 (C52 ⁇ C53) + H52 (C53-C51) + h53 (C51-C52))) / ((H51-h52) ⁇ (h52-h53) ⁇ (h53-h51))
- the interelectrode capacitances Cp52 to Cp54 can be calculated based on the processing area SD.
- the inter-electrode capacitance Cp51 is expressed by an expression not including ⁇ .
- ⁇ Cp54 can be calculated.
- the error distance ⁇ it is possible to set machining conditions that take into account machining scraps, backlash, and the like.
- the columnar electrode is described as an example of the electrode ED in FIG. 13, the electrode does not necessarily have a columnar shape, and the machining area changes continuously or discontinuously according to the progress of electric discharge machining. Such an electrode may be used. Alternatively, the electrode may have a plurality of inclined surfaces having the same inclination angle or different inclination angles to the forward end face of the electrode.
- the electrode feeding mechanism in the X, Y, and Z axis directions is configured by a ball screw mechanism and a motor
- the electrode may be moved at least in the X, Y, and Z axis directions.
- the feed mechanism may be constituted by a linear motor or the like.
- the electrode is copper and the workpiece is steel
- the example in which the reference current density is 5 A / cm 2 and 25 A / nF has been described.
- the combination of the electrode and the workpiece is In the case of different materials, a processing condition table is set separately.
- a plurality of types of machining condition tables may be prepared in advance for combinations of electrode materials and workpiece materials, and the machining condition tables corresponding to the combinations of electrodes and workpieces may be selected.
- the present invention relates to an electrical discharge machining apparatus for performing electrical discharge machining on a workpiece by discharging between an electrode and the workpiece, and a machining area of an electrical discharge machining surface or an electrode advance end surface and a machining surface of the workpiece during electrical discharge machining.
- Increase the productivity and quality of electrical discharge machining by accurately calculating the inter-electrode capacitance and setting the appropriate machining conditions according to the inter-electrode conditions such as changes in machining area and generation of machining scraps. .
Abstract
Description
特許文献3の放電加工装置では、加工屑が加工面上に堆積している場合、加工屑と電極との間に有効放電が生じるため、除去体積vと有効放電パルス数nの誤差が大きくなる。そのため、加工深さが深くなるほど加工面積の誤差が大きくなり、その加工面積に基づいて設定される加工条件の適正値からのズレが大きくなる。 In the electric discharge machining apparatus, the machining fluid is caused to flow in the gap between the electrode and the workpiece to discharge the machining waste. However, the machining waste becomes difficult to be discharged from the gap as the machining depth increases.
In the electric discharge machining apparatus of
(2)前記加工条件設定手段は、前記加工面積をパラメータとして放電加工パルスに関するピーク電流とパルスON時間とパルスOFF時間を予め設定した第1の加工条件テーブルと、前記極間静電容量をパラメータとして放電加工パルスに関するピーク電流とパルスON時間とパルスOFF時間を予め設定した第2の加工条件テーブルを有する。 A part of the constituent elements of the present invention may be configured as follows.
(2) The machining condition setting means includes a first machining condition table in which a peak current, a pulse ON time, and a pulse OFF time relating to the electric discharge machining pulse are set in advance using the machining area as a parameter, and the interelectrode capacitance as a parameter. As a second machining condition table in which the peak current, the pulse ON time, and the pulse OFF time relating to the electric discharge machining pulse are preset.
S=h1・h2・h3(h1(C2-C3)+h2(C3-C1)
+h3(C1-C2))/(ε(h1-h2)(h2-h3)(h3-h1))
に表す式を用いて前記加工面積を演算する。 (3) In the above (1) or (2), the computing means measures the first inter-electrode distance h1 and the first total capacitance C1, which are measured in a state where the electrode is moved to the first movement position, the electrode The second inter-electrode distance h2 and the second total capacitance C2 measured in a state where the electrode is moved to the second movement position, the third inter-electrode distance h3 measured in the state where the electrode is moved to the third movement position, and When the third total capacitance C3, the dielectric constant ε of the machining liquid, and the machining area S,
S = h1 · h2 · h3 (h1 (C2-C3) + h2 (C3-C1)
+ H3 (C1-C2)) / (ε (h1-h2) (h2-h3) (h3-h1))
The processing area is calculated using the formula shown in FIG.
S=((h1+α)×(h2+α)×(h3+α)×(h1(C2-C3)+h2
(C3-C1)+h3(C1-C2)))/(ε(h1-h2)×(h1-h3)
×(h3-h2))
α=A/B
但し、A=h12(h2(h3(C2-C3)+h4(C4-C2))
+h3h4(C3-C4))-h1(h22(h3(C1-C3)
+h4(C4-C1))+h2(h3+h4)(h3-h4)(C2-C1)+h3h4(h3(C1-C4)+h4(C3-C1)))-h2h3h4(h2(C3-C4)+h3(C4-C2)+h4(C2-C3))
B=h12(h2(C3-C4)+h3(C4-C2)
+h4(C2-C3))-h1(h22(C3-C4)+
h32(C4-C2)+h42(C2-C3))+h22(h3(C1-C4)
+h4(C3-C1))-h2(h32(C1-C4)+
h42(C3-C1))+h3h4(h3-h4)(C1-C2)
に表す式を用いて前記加工面積を演算する。 (4) In the above (1) or (2), the computing means measures the first inter-electrode distance h1 and the first total capacitance C1, which are measured in a state where the electrode is moved to the first movement position, the electrode The second inter-electrode distance h2 and the second total capacitance C2 measured in a state where the electrode is moved to the second moving position, and the third inter-electrode distance h3 measured in the state where the electrode is moved to the third moving position. The third total capacitance C3, the fourth inter-electrode distance h4 and the fourth total capacitance C4 measured in a state where the electrode is moved to the fourth movement position, the error distance α of the inter-electrode distance, the dielectric of the machining fluid When the rate ε and the processing area S,
S = ((h1 + α) × (h2 + α) × (h3 + α) × (h1 (C2-C3) + h2
(C3-C1) + h3 (C1-C2))) / (ε (h1-h2) × (h1-h3)
× (h3-h2))
α = A / B
However, A = h1 2 (h2 (h3 (C2-C3) + h4 (C4-C2))
+ H3h4 (C3-C4))-h1 (h2 2 (h3 (C1-C3)
+ H4 (C4-C1)) + h2 (h3 + h4) (h3-h4) (C2-C1) + h3h4 (h3 (C1-C4) + h4 (C3-C1)))-h2h3h4 (h2 (C3-C4) + h3 (C4- C2) + h4 (C2-C3))
B = h1 2 (h2 (C3-C4) + h3 (C4-C2)
+ H4 (C2-C3))-h1 (h2 2 (C3-C4) +
h3 2 (C4-C2) + h4 2 (C2-C3)) + h2 2 (h3 (C1-C4)
+ H4 (C3-C1))-h2 (h3 2 (C1-C4) +
h4 2 (C3-C1)) + h3h4 (h3-h4) (C1-C2)
The processing area is calculated using the formula shown in FIG.
S=( (h1+α)×(h2+α)×(h3+α)×(h1(C2-C3)+h2(C3-C1)+h3(C1-C2))×sinθ) /(ε(h1-h2)×(h2-h3)×(h3-h1))
α=A/B
但し、A=h12(h2(h3(C2-C3)+h4(C4-C2))
+h3h4(C3-C4))-h1(h22 (h3(C1-C3)
+h4(C4-C1))+h2(h3+h4)(h3-h4)(C2-C1)+
h3h4(h3(C1-C4)+h4(C3-C1)))-
h2h3h4(h2(C3-C4)+h3(C4-C2)+h4(C2-C3))
B=h12 (h2(C3-C4)+h3(C4-C2)
+h4(C2-C3))-h1(h22(C3-C4)+
h32(C4-C2)+h42(C2-C3))+h22(h3(C1-C4)
+h4(C3-C1))-h2(h32(C1-C4)+
h42(C3-C1))+h3h4(h3-h4)(C1-C2)
C=εS/((h1+α)sinθ) 又は
C=εS/((h2+α)sinθ) 又は
C=εS/((h3+α)sinθ) 又は
C=εS/((h4+α)sinθ)
に表す式を用いて前記加工面積及び極間静電容量を演算する。 (5) In the above (1) or (2), the arithmetic means measures the first inter-electrode distance h1 and the first total capacitance C1, which are measured in a state where the electrode is moved to the first movement position, the electrode The second inter-electrode distance h2 and the second total capacitance C2 measured in a state where the electrode is moved to the second movement position, the third inter-electrode distance h3 measured in the state where the electrode is moved to the third movement position, and The third total capacitance C3, the fourth inter-electrode distance h4 measured in a state where the electrode is moved to the fourth movement position, and the fourth total capacitance C4, the angle between the electrode advance end face and the electrode axis When θ, the error distance α of the distance between the electrodes, and the dielectric constant ε of the machining liquid, the processing area S and the capacitance between the electrodes C,
S = ((h1 + α) × (h2 + α) × (h3 + α) × (h1 (C2-C3) + h2 (C3-C1) + h3 (C1-C2)) × sin θ) / (ε (h1-h2) × (h2− h3) × (h3-h1))
α = A / B
However, A = h1 2 (h2 (h3 (C2-C3) + h4 (C4-C2))
+ H3h4 (C3-C4))-h1 (h2 2 (h3 (C1-C3)
+ H4 (C4-C1)) + h2 (h3 + h4) (h3-h4) (C2-C1) +
h3h4 (h3 (C1-C4) + h4 (C3-C1))) −
h2h3h4 (h2 (C3-C4) + h3 (C4-C2) + h4 (C2-C3))
B = h1 2 (h2 (C3-C4) + h3 (C4-C2)
+ H4 (C2-C3))-h1 (h2 2 (C3-C4) +
h3 2 (C4-C2) + h4 2 (C2-C3)) + h2 2 (h3 (C1-C4)
+ H4 (C3-C1))-h2 (h3 2 (C1-C4) +
h4 2 (C3-C1)) + h3h4 (h3-h4) (C1-C2)
C = εS / ((h1 + α) sinθ) or C = εS / ((h2 + α) sinθ) or C = εS / ((h3 + α) sinθ) or C = εS / ((h4 + α) sinθ)
The processing area and the inter-electrode capacitance are calculated using the equation shown in FIG.
(7)上記(2)~(5)の何れか1つにおいて、前記加工条件設定手段は、前記演算された加工面積又は極間静電容量に略比例するように前記電極へ供給する加工電流を設定する。 (6) In any one of the above (2) to (5), the processing condition setting means measures the total capacitance between the electrode and the processed part of the workpiece by the capacitance measuring means. The measurement cycle for changing the electric discharge machining condition is changed based on the calculated machining area or the inter-electrode capacitance.
(7) In any one of the above (2) to (5), the machining condition setting means supplies the machining current supplied to the electrodes so as to be substantially proportional to the computed machining area or inter-electrode capacitance. Set.
(9)上記(8)において、前記加工条件設定手段は、前記電極に供給する加工電流と、前記加工面積又は極間静電容量とに対応する放電パルスを設定する放電パルス設定手段を備えている。 (8) In the above (7), the machining condition setting means sets the current density of the machining current to a predetermined current density or less.
(9) In the above (8), the machining condition setting means includes a discharge pulse setting means for setting a discharge pulse corresponding to the machining current supplied to the electrode and the machining area or the interelectrode capacitance. Yes.
電極の前進端面に対向する被加工物の加工面の加工面積又はこの加工面積に比例する極間静電容量を精度良く演算することができる。つまり、加工面積又は極間静電容量を、電極を移動させた複数位置における極間距離と電極と被加工物の加工部位間の合計静電容量を用いて演算するため、加工面積又はこの加工面積に比例する極間静電容量を精度よく演算することができ、放電加工開始後の放電加工を中断した状態で求めた加工面積又は極間静電容量の高精度の演算値に基づいて、加工面積の変化や加工屑の発生等の極間状態に応じて放電加工パルスに関する加工条件を適正に設定することができる。 According to the present invention, the moving means capable of moving the electrode, the moving distance detecting means for detecting the moving distance of the electrode, and the capacitance measurement capable of measuring the total capacitance between the electrode and the processed part of the workpiece. Means, and at each measurement cycle timing after the start of electric discharge machining, with the electric discharge machining being interrupted, the electrodes are moved to a plurality of positions, the detected distances between the electrodes, and the measured total capacitances are used. The processing means for calculating the machining area of the machining surface or the inter-electrode capacitance proportional to the machining area, and the machining conditions relating to the electric discharge machining pulse based on the machining area or the inter-electrode capacitance calculated by the computing means Since the machining condition setting means for setting is provided, the following effects can be obtained.
It is possible to accurately calculate the machining area of the machining surface of the workpiece facing the forward end face of the electrode or the inter-electrode capacitance proportional to the machining area. In other words, since the machining area or the inter-electrode capacitance is calculated using the inter-electrode distance at a plurality of positions where the electrode is moved and the total capacitance between the electrode and the machining part of the workpiece, Capacitance between the electrodes in proportion to the area can be calculated with high accuracy, based on the machining area obtained in a state where the electric discharge machining after the electric discharge machining is interrupted or the calculated value of the capacitance between the electrodes with high accuracy, The machining conditions related to the electric discharge machining pulse can be appropriately set in accordance with the inter-electrode state such as the change of the machining area and the generation of machining scraps.
前記(3)の構成によれば、被加工物の表面から加工面までの距離が未知の場合であっても、加工面積を演算する演算処理の負荷を少なくできるため、演算処理速度が速く且つ正確な加工面積の演算を実行できる。 According to the configuration of (2), the electric discharge machining condition setting means sets the peak current of the electric discharge machining pulse, the pulse ON time, and the pulse OFF time based on the first and second machining condition tables. be able to.
According to the configuration of (3), even when the distance from the surface of the workpiece to the processing surface is unknown, the processing load for calculating the processing area can be reduced, so that the processing speed is high. Accurate machining area can be calculated.
前記(5)の構成によれば、被加工物の表面から加工面までの距離が未知の場合であっても、複雑形状に形成された電極前進端と加工面間の極間静電容量であって正確に加工面積に比例する極間静電容量と誤差距離の演算を実行できる。しかも、誤差距離の算出によって、加工屑やバックラッシュ等を考慮した加工条件を設定することができる。 According to the configuration (4), even when the distance from the surface of the workpiece to the machining surface is unknown, the machining area and error distance can be computed. In addition, by calculating the error distance, it is possible to set processing conditions that take into account processing scraps, backlash, and the like.
According to the configuration of (5), even if the distance from the surface of the workpiece to the machining surface is unknown, the capacitance between the electrode advance end formed in a complicated shape and the machining surface is Therefore, it is possible to calculate the capacitance between the electrodes and the error distance that are exactly proportional to the processing area. In addition, by calculating the error distance, it is possible to set processing conditions that take into account processing scraps, backlash, and the like.
前記(7)の構成によれば、加工条件設定手段により演算された加工面積又は極間静電容量に略比例するように電極へ供給する加工電流値を制御するため、電流の過剰供給に起因する電極の異状消耗を防止することができる。 According to the configuration of (6), the measurement cycle for changing the electric discharge machining conditions by measuring the total capacitance between the electrode and the machining portion of the workpiece by the capacitance calculating means is set as the machining area or the inter-electrode static. Since the change is made based on the electric capacity, the measurement cycle can be set so as to follow the shape change of the electrode advance end face, and appropriate electric discharge machining conditions can be set.
According to the configuration of (7) above, the processing current value supplied to the electrodes is controlled so as to be approximately proportional to the processing area or the inter-electrode capacitance calculated by the processing condition setting means. It is possible to prevent abnormal wear of the electrode.
前記(9)の構成によれば、放電パルス設定手段により、電極に供給する加工電流値と、加工面積又は極間静電容量とに対応する放電パルスを設定することができる。
前記(10)の構成によれば、極間距離の誤差距離に基づいてジャンプ動作のジャンプ周期とジャンプ量の少なくとも一方を設定するジャンプ動作演算手段を設けたため、加工によって発生する加工屑を加工面上から確実に排除することができ、加工処理速度の低下を防止することができる。 According to the configuration of (8), the machining condition setting unit controls the current density to be equal to or lower than the predetermined current density, so that it is possible to prevent the occurrence of problems such as a reduction in machining speed.
According to the configuration of (9), the discharge pulse corresponding to the machining current value to be supplied to the electrode and the machining area or the inter-electrode capacitance can be set by the discharge pulse setting means.
According to the configuration of (10), since the jump operation calculating means for setting at least one of the jump period and the jump amount of the jump operation based on the error distance of the distance between the poles is provided, the machining waste generated by the machining is removed from the machining surface It can be reliably excluded from the top, and a reduction in processing speed can be prevented.
図1に示すように、放電加工装置Mは、電極Eと被加工物Wの間の間隙に加工液を供給し、前記電極Eから被加工物Wへ放電パルスを印加して被加工物Wを放電加工する装置である。この放電加工装置Mは、加工機本体1と、制御装置2と、加工液槽7等の周辺機器を有する。加工機本体1は、電極Eが装備されるヘッド3と、このヘッド3を上下方向(Z軸)に往復移動可能な送り装置としてのZ軸移動機構4(移動手段)と、被加工物Wを収容した加工液槽7を図1の左右方向(X軸)に水平に往復移動可能なX軸移動機構5と、加工液槽7を左右方向に直交する前後方向(Y軸)に水平に往復移動可能なY軸移動機構6と、被加工物Wを収容し且つ加工液を貯留可能な加工液槽7と、基台8と、ケーブル25等から形成されている。電極Eは、ヘッド3の下端部に脱着可能に装備された取付板に装着されている。 Embodiments of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, the electrical discharge machining apparatus M supplies a machining liquid to a gap between the electrode E and the workpiece W, applies a discharge pulse from the electrode E to the workpiece W, and then processes the workpiece W. Is an electric discharge machine. This electric discharge machining apparatus M includes peripheral devices such as a
X軸移動機構5は、X軸可動台と、基台8に装備されたX軸方向に沿って延びる1対のX軸送りガイドとボールネジ機構とX軸モータ等で構成され、制御装置2で数値制御されるX軸モータの駆動によりX軸可動台がX軸方向へ移動駆動される。Y軸移動機構6は、Y軸可動台と、X軸可動台に装備されたY軸方向に沿って延びる1対のY軸送りガイドとボールネジ機構とY軸モータ等で構成されている。制御装置2で数値制御されるY軸モータの駆動によりY軸可動台と加工液槽7がY軸方向へ移動駆動される。 The Z-
The
Since the electrode E and the processing part of the workpiece W are opposed to each other with a gap, the
尚、静電容量測定部12は、前述の構成に限られるものではなく、少なくとも電極Eと被加工物Wの加工部位との間の合計静電容量Cを測定可能であれば種々の構成を採用可能である。 As shown in FIG. 4, when a pulse is output from the
The
位置制御部16は、Z軸移動機構4によりヘッド3を上下方向に移動駆動することにより電極Eの前進端面から加工面までの極間距離を変更可能に形成されている。位置制御部16は、電極Eの前進端面から加工面までの極間距離を検出可能に形成されている。 The
The
C1=Cp1+Ca …(1)
但し、Cp1=εS/h1である。 Specifically, the electrode E is brought into contact with the processing surface Wf of the workpiece W to initialize the distance between the electrodes to zero. Next, as shown in FIG. 5A, the Z-
C1 = Cp1 + Ca (1)
However, Cp1 = εS / h1.
C2=Cp2+Ca・d2/d1 …(2)
但し、Cp2=εS/h2である。 Next, as shown in FIG. 5B, the Z-
C2 = Cp2 + Ca · d2 / d1 (2)
However, Cp2 = εS / h2.
S=(h1・h2(C2・d1-C1・d2))/(ε(d1・h1-d2・h2))
…(3)
尚、被加工物Wの表面から電極前進端面までの距離d1,d2は、被加工物Wの表面から加工面Wfまでの距離が位置制御部16において既知であるため、第1,第2極間距離h1,h2と誘電率εを用いて算出することができる。 When the above formulas (1) and (2) are obtained for the machining area S, the machining area S can be expressed by the following formula (3).
S = (h1 · h2 (C2 · d1−C1 · d2)) / (ε (d1 · h1−d2 · h2))
... (3)
The distances d1 and d2 from the surface of the workpiece W to the electrode advance end surface are known in the
加工液の誘電率εは、加工面積が既知である標準電極Eaを用いて求める。図6(a)に示すように、標準電極Eaを被加工物Wの表面と接触させて電極Eaの極間距離を零に初期化する。次に、図6(b)に示すように、標準電極Eaを被加工物Wの表面から距離h0の位置まで移動し、この位置における合計静電容量C0を静電容量測定部12と静電容量測定制御部17により測定する。標準電極Eaの被加工物Wに対向する面積をS0とすると、誘電率εは次式(4)で表すことができる。
ε=h0・C0/S0 …(4) An example of a technique for detecting the dielectric constant ε of the machining fluid will be described.
The dielectric constant ε of the working fluid is obtained using a standard electrode Ea whose working area is known. As shown in FIG. 6A, the standard electrode Ea is brought into contact with the surface of the workpiece W to initialize the distance between the electrodes Ea to zero. Next, as shown in FIG. 6 (b), the standard electrode Ea is moved from the surface of the workpiece W to a position at a distance h0, and the total capacitance C0 at this position is compared with the
ε = h0 · C0 / S0 (4)
また、加工面積Sの演算値を用いて第1,第2極間静電容量Cp1,Cp2を演算することにより、極間静電容量の増減傾向から加工屑の有無等を検出することができる。つまり、Z軸移動機構4の駆動をバックラッシュの発生しないボールネジ機構やリニアモータ等によって行う場合、h1=h2/2としたとき、理論上、Cp1=2Cp2となる。それ故、第2極間静電容量Cp2が第1極間静電容量Cp1の1/2の値よりも小さいときは被加工物Wの加工面上に加工屑が堆積していることを検出でき、第2極間静電容量Cp2が1/2Cp1よりも小さいほど、被加工物Wの加工面上の加工屑の堆積量が大きいことを検出することができる。 As described above, the first and second total capacitances C1 and C2, the first and second inter-electrode distances h1 and h2, and the distance from the surface of the workpiece W to the electrode advance end surface Ef with respect to the expression (3). By substituting d1 and d2 and the dielectric constant ε, the processing area S of the processing surface Wf of the workpiece W is calculated.
Further, by calculating the first and second inter-electrode capacitances Cp1 and Cp2 using the calculated value of the processing area S, it is possible to detect the presence / absence of processing waste or the like from the increase / decrease tendency of the inter-electrode capacitance. . That is, when the Z-
Cp21=εSA/(h21・sinθ) …(5)
C21=εSA/(h21・sinθ)+Ca …(6) First, the electrode EA is brought into contact with the processing surface of the workpiece W to initialize the distance between the electrodes to zero. Next, as shown in FIG. 7A, the Z-
Cp21 = εSA / (h21 · sin θ) (5)
C21 = εSA / (h21 · sin θ) + Ca (6)
Cp22=εSA/(h22・sinθ) …(7)
C22=εSA/(h22・sinθ)+Ca・d22/d21 …(8) Next, as shown in FIG. 7B, the
Cp22 = εSA / (h22 · sin θ) (7)
C22 = εSA / (h22 · sin θ) + Ca · d22 / d21 (8)
SA=(h21・h22(C22・d21-C21・d22))
×sinθ/(ε(d21・h21-d22・h22)) …(9) When the formulas (6) and (8) are solved for the machining area SA of the machining surface of the workpiece W, the machining area SA can be expressed by the following formula (9).
SA = (h21 · h22 (C22 · d21-C21 · d22))
× sin θ / (ε (d21 · h21−d22 · h22)) (9)
Cp21=h22(C22・d21-C21・d22)/(d21・h21-d22・h22)…(10)
前記式(7)に前記式(9)を代入することによって、第2移動位置d22における極間静電容量Cp22は次式(11)によって表すことができる。
Cp22=h21(C22・d21-C21・d22)/(d21・h21-d22・h22)…(11) Here, by substituting the equation (9) into the equation (5), the interelectrode capacitance Cp21 at the first movement position d21 can be expressed by the following equation (10).
Cp21 = h22 (C22 · d21−C21 · d22) / (d21 · h21−d22 · h22) (10)
By substituting the equation (9) into the equation (7), the inter-electrode capacitance Cp22 at the second movement position d22 can be expressed by the following equation (11).
Cp22 = h21 (C22 · d21−C21 · d22) / (d21 · h21−d22 · h22) (11)
尚、表1,表2に示す加工条件テーブルは、一例にすぎず、加工液の誘電率や電極の材質と被加工物の材質の組み合わせ、若しくは加工条件等によって適宜変更可能である。 When the capacitance calculation mode is set, the machining
The processing condition tables shown in Tables 1 and 2 are merely examples, and can be appropriately changed depending on the dielectric constant of the processing liquid, the combination of the material of the electrode and the material of the workpiece, or the processing conditions.
図8のマップは、誤差距離αが増大するほどジャンプ周期が小さくなるように設定され、図9のマップは、誤差距離αが増大するほどジャンプ移動量が増大するように設定されている。尚、図8,図9に示すマップは、一例にすぎず、加工形状や加工条件等によって適宜変更可能である。 However, although the calculation technique of the error distance α of the distance between the poles will be described in the third and fourth embodiments, the processing area and the capacitance between the poles are calculated as shown in FIGS. When the distance α is not calculated, a default error distance (for example, 4 μm) may be applied.
The map of FIG. 8 is set so that the jump cycle decreases as the error distance α increases, and the map of FIG. 9 is set so that the jump movement amount increases as the error distance α increases. The maps shown in FIGS. 8 and 9 are merely examples, and can be changed as appropriate depending on the machining shape, machining conditions, and the like.
S6の判定の結果、加工面積演算モードが選択されている場合、S7において加工面積演算処理を行う。加工面積演算部21は、式(3)に対して第1,第2合計静電容量C1,C2、第1,第2極間距離h1,h2及び距離d1,d2を代入することによって加工面積Sを演算する。加工面積の演算後、S9に移行する。 Next, in S6, it is determined whether the machining area calculation mode is selected.
If the machining area calculation mode is selected as a result of the determination in S6, a machining area calculation process is performed in S7. The machining
S6の判定の結果、静電容量演算モードが選択されている場合、S8へ移行して静電容量演算処理を行う。静電容量演算部22は、式(10)又は式(11)に対して第1,第2合計静電容量C1,C2、第1,第2極間距離h1,h2及び距離d1,d2を代入することによって第1,第2極間静電容量Cp1,Cp2の少なくとも何れか一方について演算する。尚、第1極間距離h1は、目標極間距離である。 In the example shown in FIG. 7, the electric discharge machining condition setting process executed in the capacitance calculation mode is substantially the same as described above.
If the electrostatic capacity calculation mode is selected as a result of the determination in S6, the process proceeds to S8 to perform the electrostatic capacity calculation process. The capacitance calculator 22 calculates the first and second total capacitances C1 and C2, the first and second inter-electrode distances h1 and h2, and the distances d1 and d2 with respect to the equation (10) or the equation (11). By substituting, calculation is performed for at least one of the first and second inter-electrode capacitances Cp1, Cp2. The first inter-electrode distance h1 is a target inter-electrode distance.
測定した第1,第2極間距離h1,h2と、測定した電極と被加工物の加工部位間の第1,第2合計静電容量C1,C2を用いて加工面積を算出するため、被加工物Wの加工面の加工面積Sを精度よく求めることができる。また、電極前進端面が複雑形状のため、加工面積SAの演算が困難である場合でも、加工面積SAと略比例関係にある第1極間静電容量Cp21或いは第2極間静電容量Cp22を、上記と同様に精度よく求めることができる。 Next, the operation and effect of the electric discharge machining apparatus M will be described.
In order to calculate the processing area using the measured first and second inter-electrode distances h1 and h2 and the first and second total capacitances C1 and C2 between the measured electrodes and the processed portion of the workpiece, The processing area S of the processed surface of the workpiece W can be obtained with high accuracy. Further, even if it is difficult to calculate the machining area SA because the electrode advance end face has a complicated shape, the first inter-electrode capacitance Cp21 or the second inter-electrode capacitance Cp22 that is approximately proportional to the machining area SA is obtained. As with the above, it can be obtained with high accuracy.
静電容量演算部22は、式(9)~式(11)に基づいて極間静電容量Cp21,Cp22を演算するため、電極前進端面が複雑形状であっても、加工面積SAに比例した極間静電容量Cp21,Cp22を正確に演算することができる。 Since the machining
Since the capacitance calculation unit 22 calculates the interelectrode capacitances Cp21 and Cp22 based on the equations (9) to (11), even if the electrode advance end face has a complicated shape, it is proportional to the machining area SA. The interelectrode capacitances Cp21 and Cp22 can be accurately calculated.
実施例1との相違点は、実施例1では被加工物Wの表面から加工面までの距離Dが既知であったのに対して、実施例2では距離Dが未知としている。 Next, Example 2 will be described with reference to FIG.
The difference from the first embodiment is that the distance D from the surface of the workpiece W to the processing surface is known in the first embodiment, whereas the distance D is unknown in the second embodiment.
C31=Cp31+Ca(D-h31)/D …(12)
但し、極間静電容量Cp31=εSB/h31である。 The column-shaped electrode EB is brought into contact with the processed surface of the workpiece W to initialize the movement position (distance between the electrodes) of the electrode EB. Next, as shown in FIG. 11A, the electrode EB is moved upward by the Z-
C31 = Cp31 + Ca (D−h31) / D (12)
However, the interelectrode capacitance Cp31 = εSB / h31.
C32=Cp32+Ca(D-h32)/D …(13)
但し、極間静電容量Cp32=εSB/h32である。 Next, as shown in FIG. 11B, the Z-
C32 = Cp32 + Ca (D−h32) / D (13)
However, the interelectrode capacitance Cp32 = εSB / h32.
C33=Cp33+Ca(D-h33)/D …(14)
但し、極間静電容量Cp33=εSB/h33である。 Next, as shown in FIG. 11C, the Z-
C33 = Cp33 + Ca (D−h33) / D (14)
However, the interelectrode capacitance Cp33 = εSB / h33.
SB=h31・h32・h33(h31(C32-C33)+h32(C33-C31)
+h33(C31-C32))/(ε(h31-h32)(h32-h33)(h33-h31))
…(15) When the equations (12) to (14) are solved for the machining area SB, the machining area SB can be expressed by the following equation (15).
SB = h31 · h32 · h33 (h31 (C32 – C33) + h32 (C33 – C31)
+ H33 (C31-C32)) / (ε (h31-h32) (h32-h33) (h33-h31))
... (15)
放電パルス設定部23は、加工電流測定部14によって検出された加工電流値と加工面積SBを用いて電流密度を演算し、この電流密度が所定の電流密度以下になるように制御している。加工条件設定部19は、実施例1と同様に、加工面積SBを表1の加工条件テーブルに適用することで、放電パルスなどの電気的加工条件を設定する。 The machining
The discharge
基本的に実施例1と同様の作用、効果を奏する。しかも、被加工物Wの表面から加工面までの距離Dが不明の場合でも、第1~第3移動位置の極間距離h31~h33と合計静電容量C31~C33の検出により適正な加工条件を設定することができる。
尚、図11に示す電極EBは柱形状の電極を例にして説明したが、電極EBは必ずしも柱形状である必要はないし、放電加工の進行に応じて加工面積が連続的に又は不連続的に変化するような電極であってもよい。 Next, the operation and effect of the electric discharge machining apparatus M of Example 2 will be described.
There are basically the same operations and effects as in the first embodiment. In addition, even when the distance D from the surface of the workpiece W to the processing surface is unknown, appropriate processing conditions can be obtained by detecting the interelectrode distances h31 to h33 and the total capacitances C31 to C33 at the first to third movement positions. Can be set.
The electrode EB shown in FIG. 11 has been described by taking a columnar electrode as an example. However, the electrode EB does not necessarily have a columnar shape, and the machining area continuously or discontinuously according to the progress of electric discharge machining. The electrode may change to
実施例1との相違点は、実施例1では被加工物Wの表面から加工面までの距離Dが既知であるのに対して、実施例3では距離Dが未知とされ、且つ測定した極間距離に誤差距離αを含む点である。尚、誤差距離αは、被加工物Wの加工面上に堆積した加工屑やZ軸移動機構4のギア系のバックラッシュ等に起因しており、バックラッシュが生じない場合、正の値として加工面上の加工屑の堆積量を表し、バックラッシュが生じる場合、負の値としてのバックラッシュ量と正の値としての加工屑の堆積量との合算値を表している。 Next, Example 3 will be described with reference to FIG.
The difference from the first embodiment is that, in the first embodiment, the distance D from the surface of the workpiece W to the processing surface is known, whereas in the third embodiment, the distance D is unknown and the measured pole This is a point that includes the error distance α in the distance between them. The error distance α is caused by processing debris accumulated on the processing surface of the workpiece W, the backlash of the gear system of the Z-
C41=Cp41+Ca(D-h41-α)/D …(16)
但し、極間静電容量Cp41=εSC/(h41+α)である。 The columnar electrode EC is brought into contact with the processing surface of the workpiece W to initialize the movement position (distance between the electrodes) of the electrode EC. Next, as shown in FIG. 12A, the electrode EC is moved upward by the Z-
C41 = Cp41 + Ca (D−h41−α) / D (16)
However, the interelectrode capacitance Cp41 = εSC / (h41 + α).
C42=Cp42+Ca(D-h42-α)/D …(17)
但し、極間静電容量Cp42=εSC/(h42+α)である。 Next, as shown in FIG. 12B, the electrode EC is further moved upward from the first movement position by the Z-
C42 = Cp42 + Ca (D−h42−α) / D (17)
However, the interelectrode capacitance Cp42 = εSC / (h42 + α).
C43=Cp43+Ca(D-h43-α)/D …(18)
但し、極間静電容量Cp43=εSC/(h43+α)である。 Next, as shown in FIG. 12C, the electrode EC is further moved upward from the second movement position by the Z-
C43 = Cp43 + Ca (D−h43−α) / D (18)
However, the interelectrode capacitance Cp43 = εSC / (h43 + α).
C44=Cp44+Ca(D-h44-α)/D …(19)
但し、極間静電容量Cp44=εS/(h44+α)である。 Next, as shown in FIG. 12D, the electrode EC is moved further upward from the third movement position by the Z-
C44 = Cp44 + Ca (D−h44−α) / D (19)
However, the interelectrode capacitance Cp44 = εS / (h44 + α).
SC=((h41+α)×(h42+α)×(h43+α)×(h41(C42-C43)+h42(C43-C41)+h43(C41-C42)))/(ε(h41-h42)×(h41-h43)×(h43-h42)) …(20) When the equations (16) to (19) are solved for the machining area SC, the machining area SC can be expressed by the following equation (20) including the error distance α.
SC = ((h41 + α) × (h42 + α) × (h43 + α) × (h41 (C42−C43) + h42 (C43−C41) + h43 (C41−C42))) / (ε (h41−h42) × (h41−h43) × (h43-h42))… (20)
α=A/B …(21)
但し、A=h412(h42(h43(C42-C43)+h44(C44-C42))
+h43h44(C43-C44))-h41(h422(h43(C41-C43)
+h44(C44-C41))+h42(h43+h44)(h43-h44)(C42-C41)+h43h44(h43(C41-C44)+h44(C43-C41)))-h42h43h44(h42(C3-C4)+h43(C4-C2)+h44(C2-C3))
B=h412(h42(C43-C44)+h43(C44-C42)
+h44(C42-C43))-h41(h422(C43-C44)+
h432(C44-C42)+h442(C42-C43))+h422(h43(C41-C44)
+h44(C43-C41))-h42(h432(C41-C44)+
h442(C43-C41))+h43h44(h43-h44)(C41-C42) When the error distance α is obtained, it can be expressed by the following equation (21).
α = A / B (21)
However, A = h41 2 (h42 (h43 (C42−C43) + h44 (C44−C42))
+ H43h44 (C43-C44))-h41 (h42 2 (h43 (C41-C43)
+ H44 (C44-C41)) + h42 (h43 + h44) (h43-h44) (C42-C41) + h43h44 (h43 (C41-C44) + h44 (C43-C41)))-h42h43h44 (h42 (C3-C4) + h43 (C4- C2) + h44 (C2-C3))
B = h41 2 (h42 (C43−C44) + h43 (C44−C42)
+ H44 (C42−C43)) − h41 (h42 2 (C43−C44) +
h43 2 (C44-C42) + h44 2 (C42-C43)) + h42 2 (h43 (C41-C44)
+ H44 (C43−C41)) − h42 (h43 2 (C41−C44) +
h44 2 (C43-C41)) + h43h44 (h43-h44) (C41-C42)
基本的に実施例1と同様の作用、効果を奏する。しかも、被加工物Wの表面から加工面までの距離Dが不明の場合でも、第1~第4移動位置の極間距離h41~h44と合計静電容量C41~C44の検出によって加工面積SCを精度よく演算し、適正な加工条件を設定することができる。しかも、誤差距離αの算出によって、加工屑やバックラッシュ等を考慮して加工面積SCを精度よく演算し、加工条件を適切に設定することができる。
尚、図12に示す電極ECは柱形状の電極を例として説明したが、電極は必ずしも柱形状である必要はなく、放電加工の進行に応じて加工面積が連続的又は不連続的に変化する電極であってもよい。 Next, operations and effects of the electric discharge machining apparatus M according to the third embodiment will be described.
There are basically the same operations and effects as in the first embodiment. Moreover, even when the distance D from the surface of the workpiece W to the machining surface is unknown, the machining area SC is determined by detecting the inter-electrode distances h41 to h44 and the total capacitances C41 to C44 at the first to fourth movement positions. It is possible to calculate accurately and set appropriate machining conditions. In addition, by calculating the error distance α, the machining area SC can be accurately calculated in consideration of machining scraps, backlash, and the like, and the machining conditions can be set appropriately.
Although the electrode EC shown in FIG. 12 has been described by taking a columnar electrode as an example, the electrode does not necessarily have a columnar shape, and the machining area changes continuously or discontinuously according to the progress of electric discharge machining. It may be an electrode.
実施例1との相違点は、実施例1では被加工物Wの表面から加工面までの距離Dが既知であるのに対して、実施例4では距離Dが未知とされ、測定した極間距離に誤差距離αを含むと共に電極前進端面が複雑形状とされる点である。 Next, Example 4 will be described with reference to FIG.
The difference from the first embodiment is that the distance D from the surface of the workpiece W to the processing surface is known in the first embodiment, whereas the distance D is unknown in the fourth embodiment, and the measured distance between the electrodes The distance includes the error distance α and the electrode advance end face has a complicated shape.
C51=εSD/((h51+α)sinθ)+Ca(D-h51-α)/D …(22)
但し、極間静電容量Cp51=εSD/((h51+α)sinθ)である。 A column-shaped electrode ED having an angle θ (0 ° <θ <90 °) between the electrode advance end surface and the electrode axis (vertical surface) is brought into contact with the processing surface of the workpiece W to move the electrode ED ( Initialize the distance between the poles. Next, as shown in FIG. 13A, the electrode ED is moved and driven upward by the Z-
C51 = εSD / ((h51 + α) sinθ) + Ca (D−h51−α) / D (22)
However, the interelectrode capacitance Cp51 = εSD / ((h51 + α) sinθ).
C52=εSD/((h52+α)sinθ)+Ca(D-h52-α)/D …(23)
但し、極間静電容量Cp52=εSD/((h52+α)sinθ)である。 Next, as shown in FIG. 13B, the electrode ED is further moved upward from the first movement position by the Z-
C52 = εSD / ((h52 + α) sinθ) + Ca (D−h52−α) / D (23)
However, the interelectrode capacitance Cp52 = εSD / ((h52 + α) sinθ).
C53=εSD/((h53+α)sinθ)+Ca(D-h53-α)/D …(24)
但し、極間静電容量Cp53=εSD/((h53+α)sinθ)である。 Next, as shown in FIG. 13C, the electrode ED is further moved upward from the second movement position by the Z-
C53 = εSD / ((h53 + α) sinθ) + Ca (D−h53−α) / D (24)
However, the interelectrode capacitance Cp53 = εSD / ((h53 + α) sinθ).
C54=εSD/((h54+α)sinθ)+Ca(D-h54-α)/D …(25)
但し、極間静電容量Cp54=εSD/((h54+α)sinθ)である。 Next, as shown in FIG. 13D, the Z-
C54 = εSD / ((h54 + α) sinθ) + Ca (D−h54−α) / D (25)
However, the interelectrode capacitance Cp54 = εSD / ((h54 + α) sinθ).
SD=((h51+α)×(h52+α)×(h53+α)×(h51(C52-C53)
+h52(C53-C51)+h53(C51-C52))×sinθ)/
(ε(h51-h52)×(h52-h53)×(h53-h51)) …(26)
また、同様に式(22)~式(25)を誤差距離αについて解くことによって、誤差距離αを求めることができる。 When the equations (22) to (25) are solved for the machining area SD, the machining area SD can be expressed by the following equation (26) including the error distance α.
SD = ((h51 + α) × (h52 + α) × (h53 + α) × (h51 (C52−C53)
+ H52 (C53−C51) + h53 (C51−C52)) × sin θ) /
(Ε (h51−h52) × (h52−h53) × (h53−h51)) (26)
Similarly, the error distance α can be obtained by solving the equations (22) to (25) for the error distance α.
Cp51=((h52+α)×(h53+α)×(h51(C52-C53)
+h52(C53-C51)+h53(C51-C52)))/
((h51-h52)×(h52-h53)×(h53-h51)) …(27)
同様に、加工面積SDに基づいて極間静電容量Cp52~Cp54を演算することができる。 Here, by substituting the equation (26) into the equation for the interelectrode capacitance Cp51, the interelectrode capacitance Cp51 at the first movement position d51 can be expressed by the following equation (27).
Cp51 = ((h52 + α) × (h53 + α) × (h51 (C52−C53)
+ H52 (C53-C51) + h53 (C51-C52))) /
((H51-h52) × (h52-h53) × (h53-h51)) (27)
Similarly, the interelectrode capacitances Cp52 to Cp54 can be calculated based on the processing area SD.
1〕前記実施例においては、電極を上下方向に移動して加工処理を行う例を説明したが、本発明は電極を水平に左右方向又は前後方向へ移動して加工処理を行う放電加工装置にも適用可能である。 Next, a modification in which the above embodiment is partially changed will be described.
1) In the above-described embodiment, the example in which the machining process is performed by moving the electrode in the vertical direction has been described. Is also applicable.
W 被加工物
E~ED 電極
1 加工機本体
2 制御装置
4 Z軸移動機構
9 演算処理部
12 静電容量測定部
13 放電制御部
16 位置制御部
17 静電容量測定制御部
18 演算手段
19 加工条件設定部
21 加工面積演算部
22 静電容量演算部
23 放電パルス設定部
24 測定周期演算部
25 ジャンプ動作演算部 M Electrical Discharge Machining Machine W Workpiece E to
Claims (10)
- 電極と被加工物の間の間隙に加工液を供給し、前記電極から被加工物へ放電パルスを印加して前記被加工物を放電加工する放電加工装置において、
前記電極を移動可能で且つ電極の加工進行方向前進端面から被加工物の加工面までの極間距離を変更可能な移動手段と、
前記電極の移動距離を検知する移動距離検知手段と、
前記電極に前記間隙を隔てて対向する被加工物の加工部位と前記電極との間の合計静電容量を測定可能な静電容量測定手段と、
放電加工開始後の測定周期タイミング毎に、前記放電加工を中断した状態で、前記移動手段により前記電極を複数位置に移動させ、前記移動距離検知手段により検知した複数の極間距離及び前記静電容量測定手段により測定した複数の合計静電容量を用いて、前記加工面の加工面積又はこの加工面積に比例する極間静電容量を演算する演算手段と、
前記演算手段により演算された前記加工面積又は前記極間静電容量に基づいて放電加工パルスに関する加工条件を設定する加工条件設定手段と、
を備えたことを特徴とする放電加工装置。 In an electric discharge machining apparatus that supplies a machining liquid to a gap between an electrode and a workpiece, and applies an electric discharge pulse from the electrode to the workpiece to discharge-process the workpiece.
A moving means capable of moving the electrode and capable of changing a distance between the electrodes from the advancing end face in the machining progress direction of the electrode to the machining surface of the workpiece;
A moving distance detecting means for detecting a moving distance of the electrode;
A capacitance measuring means capable of measuring a total capacitance between a processed portion of the workpiece and the electrode facing the electrode with the gap therebetween;
At each measurement cycle timing after the start of electric discharge machining, with the electric discharge machining interrupted, the electrode is moved to a plurality of positions by the moving means, and the plurality of inter-electrode distances detected by the moving distance detecting means and the electrostatic Using a plurality of total capacitances measured by the capacitance measuring means, calculating means for calculating the processing area of the processing surface or the interelectrode capacitance proportional to the processing area;
Machining condition setting means for setting machining conditions related to an electric discharge machining pulse based on the machining area or the interelectrode capacitance calculated by the computing means;
An electrical discharge machining apparatus comprising: - 前記加工条件設定手段は、前記加工面積をパラメータとして放電加工パルスに関するピーク電流とパルスON時間とパルスOFF時間を予め設定した第1の加工条件テーブルと、前記極間静電容量をパラメータとして放電加工パルスに関するピーク電流とパルスON時間とパルスOFF時間を予め設定した第2の加工条件テーブルを有することを特徴とする請求項1に記載の放電加工装置 The machining condition setting means includes a first machining condition table in which a peak current, a pulse ON time and a pulse OFF time relating to an electric discharge machining pulse are set in advance using the machining area as a parameter, and electric discharge machining using the inter-electrode capacitance as a parameter. The electric discharge machining apparatus according to claim 1, further comprising a second machining condition table in which a peak current relating to a pulse, a pulse ON time, and a pulse OFF time are set in advance.
- 前記演算手段は、前記電極を第1移動位置に移動させた状態において測定した第1極間距離h1及び第1合計静電容量C1、前記電極を第2移動位置に移動させた状態において測定した第2極間距離h2及び第2合計静電容量C2、前記電極を第3移動位置に移動させた状態において測定した第3極間距離h3及び第3合計静電容量C3、加工液の誘電率εとし、前記加工面積Sとしたとき、
S=h1・h2・h3(h1(C2-C3)+h2(C3-C1)
+h3(C1-C2))/(ε(h1-h2)(h2-h3)(h3-h1))
に表す式を用いて前記加工面積を演算することを特徴とする請求項1又は2に記載の放電加工装置。 The arithmetic means measures the first interelectrode distance h1 and the first total capacitance C1 measured in a state where the electrode is moved to the first movement position, and the electrode is moved to the second movement position. Second inter-electrode distance h2 and second total capacitance C2, third inter-electrode distance h3 and third total capacitance C3 measured in a state where the electrode is moved to the third movement position, and the dielectric constant of the working fluid When ε is the processing area S,
S = h1 · h2 · h3 (h1 (C2-C3) + h2 (C3-C1)
+ H3 (C1-C2)) / (ε (h1-h2) (h2-h3) (h3-h1))
The electric discharge machining apparatus according to claim 1, wherein the machining area is calculated using an expression represented by: - 前記演算手段は、前記電極を第1移動位置に移動させた状態において測定した第1極間距離h1と第1合計静電容量C1、前記電極を第2移動位置に移動させた状態において測定した第2極間距離h2と第2合計静電容量C2、前記電極を第3移動位置に移動させた状態において測定した第3極間距離h3と第3合計静電容量C3、前記電極を第4移動位置に移動させた状態において測定した第4極間距離h4と第4合計静電容量C4、極間距離の誤差距離α、加工液の誘電率εとし、加工面積Sとしたとき、
S=((h1+α)×(h2+α)×(h3+α)×(h1(C2-C3)+h2(C3-C1)+h3(C1-C2)))/(ε(h1-h2)×(h1-h3)×(h3-h2))
α=A/B
但し、A=h12(h2(h3(C2-C3)+h4(C4-C2))
+h3h4(C3-C4))-h1(h22(h3(C1-C3)
+h4(C4-C1))+h2(h3+h4)(h3-h4)(C2-C1)+
h3h4(h3(C1-C4)+h4(C3-C1)))-
h2h3h4(h2(C3-C4)+h3(C4-C2)+h4(C2-C3))
B=h12(h2(C3-C4)+h3(C4-C2)
+h4(C2-C3))-h1(h22(C3-C4)+
h32(C4-C2)+h42(C2-C3))+h22(h3(C1-C4)
+h4(C3-C1))-h2(h32(C1-C4)+
h42(C3-C1))+h3h4(h3-h4)(C1-C2)
に表す式を用いて前記加工面積を演算することを特徴とする請求項1又は2に記載の放電加工装置。 The arithmetic means measures the first inter-electrode distance h1 and the first total capacitance C1 measured in a state where the electrode is moved to the first movement position, and the state in which the electrode is moved to the second movement position. The second inter-electrode distance h2 and the second total capacitance C2, the third inter-electrode distance h3 and the third total capacitance C3 measured in a state in which the electrode is moved to the third movement position, the fourth electrode When the fourth inter-electrode distance h4 and the fourth total capacitance C4 measured in the state of being moved to the moving position, the inter-electrode distance error distance α, and the dielectric constant ε of the processing liquid, and the processing area S,
S = ((h1 + α) × (h2 + α) × (h3 + α) × (h1 (C2-C3) + h2 (C3-C1) + h3 (C1-C2))) / (ε (h1-h2) × (h1-h3) × (h3-h2))
α = A / B
However, A = h1 2 (h2 (h3 (C2-C3) + h4 (C4-C2))
+ H3h4 (C3-C4))-h1 (h2 2 (h3 (C1-C3)
+ H4 (C4-C1)) + h2 (h3 + h4) (h3-h4) (C2-C1) +
h3h4 (h3 (C1-C4) + h4 (C3-C1))) −
h2h3h4 (h2 (C3-C4) + h3 (C4-C2) + h4 (C2-C3))
B = h1 2 (h2 (C3-C4) + h3 (C4-C2)
+ H4 (C2-C3))-h1 (h2 2 (C3-C4) +
h3 2 (C4-C2) + h4 2 (C2-C3)) + h2 2 (h3 (C1-C4)
+ H4 (C3-C1))-h2 (h3 2 (C1-C4) +
h4 2 (C3-C1)) + h3h4 (h3-h4) (C1-C2)
The electric discharge machining apparatus according to claim 1, wherein the machining area is calculated using an expression represented by: - 前記演算手段は、前記電極を第1移動位置に移動させた状態において測定した第1極間距離h1及び第1合計静電容量C1、前記電極を第2移動位置に移動させた状態において測定した第2極間距離h2及び第2合計静電容量C2、前記電極を第3移動位置に移動させた状態において測定した第3極間距離h3及び第3合計静電容量C3、前記電極を第4移動位置に移動させた状態において測定した第4極間距離h4及び第4合計静電容量C4、電極前進端面と電極の軸心の間の角度θ、極間距離の誤差距離α、加工液の誘電率εとし、前記加工面積S、前記極間静電容量Cとしたとき、
S=( (h1+α)×(h2+α)×(h3+α)×(h1(C2-C3)+h2(C3-C1)+h3(C1-C2))×sinθ) /(ε(h1-h2)×(h2-h3)×
(h3-h1))
α=A/B
但し、A=h12(h2(h3(C2-C3)+h4(C4-C2))
+h3h4(C3-C4))-h1(h22(h3(C1-C3)
+h4(C4-C1))+h2(h3+h4)(h3-h4)(C2-C1)+
h3h4(h3(C1-C4)+h4(C3-C1)))-
h2h3h4(h2(C3-C4)+h3(C4-C2)+h4(C2-C3))
B=h12(h2(C3-C4)+h3(C4-C2)
+h4(C2-C3))-h1(h22(C3-C4)+h32(C4-C2)
+h42(C2-C3))+h22(h3(C1-C4)
+h4(C3-C1))-h2(h32(C1-C4)+h42(C3-C1))
+h3h4(h3-h4)(C1-C2)
C=εS/((h1+α)sinθ) 又は
C=εS/((h2+α)sinθ) 又は
C=εS/((h3+α)sinθ) 又は
C=εS/((h4+α)sinθ)
に表す式を用いて前記加工面積及び極間静電容量を演算することを特徴とする請求項1又は2に記載の放電加工装置。 The arithmetic means measures the first interelectrode distance h1 and the first total capacitance C1 measured in a state where the electrode is moved to the first movement position, and the electrode is moved to the second movement position. Second inter-electrode distance h2 and second total capacitance C2, third inter-electrode distance h3 and third total capacitance C3 measured in a state where the electrode is moved to the third movement position, and the fourth electrode. The distance between the fourth pole h4 and the fourth total capacitance C4 measured in the state of being moved to the moving position, the angle θ between the electrode advance end face and the electrode axis, the error distance α of the distance between the poles, When the dielectric constant ε, the processing area S, and the interelectrode capacitance C,
S = ((h1 + α) × (h2 + α) × (h3 + α) × (h1 (C2-C3) + h2 (C3-C1) + h3 (C1-C2)) × sin θ) / (ε (h1-h2) × (h2− h3) ×
(H3-h1))
α = A / B
However, A = h1 2 (h2 (h3 (C2-C3) + h4 (C4-C2))
+ H3h4 (C3-C4))-h1 (h2 2 (h3 (C1-C3)
+ H4 (C4-C1)) + h2 (h3 + h4) (h3-h4) (C2-C1) +
h3h4 (h3 (C1-C4) + h4 (C3-C1))) −
h2h3h4 (h2 (C3-C4) + h3 (C4-C2) + h4 (C2-C3))
B = h1 2 (h2 (C3-C4) + h3 (C4-C2)
+ H4 (C2-C3))-h1 (h2 2 (C3-C4) + h3 2 (C4-C2)
+ H4 2 (C2-C3)) + h2 2 (h3 (C1-C4)
+ H4 (C3-C1))-h2 (h3 2 (C1-C4) + h4 2 (C3-C1))
+ H3h4 (h3-h4) (C1-C2)
C = εS / ((h1 + α) sinθ) or C = εS / ((h2 + α) sinθ) or C = εS / ((h3 + α) sinθ) or C = εS / ((h4 + α) sinθ)
The electric discharge machining apparatus according to claim 1, wherein the machining area and the inter-electrode capacitance are calculated using an expression represented by: - 前記加工条件設定手段は、前記静電容量測定手段により電極と被加工物の加工部位間の合計静電容量を測定して放電加工条件を変更する測定周期を前記演算された加工面積又は極間静電容量に基づいて変更することを特徴とする請求項2~5の何れか1つに記載の放電加工装置。 The machining condition setting means measures the total capacitance between the electrode and the machining part of the workpiece by the capacitance measuring means, and sets the measurement cycle for changing the electric discharge machining condition to the calculated machining area or between the electrodes. 6. The electric discharge machining apparatus according to claim 2, wherein the electric discharge machining apparatus is changed based on an electrostatic capacity.
- 前記加工条件設定手段は、前記演算された加工面積又は極間静電容量に略比例するように前記電極へ供給する加工電流を設定することを特徴とする請求項2~5の何れか1つに記載の放電加工装置。 6. The machining condition setting means sets a machining current to be supplied to the electrodes so as to be substantially proportional to the calculated machining area or interelectrode capacitance. The electric discharge machining apparatus according to 1.
- 前記加工条件設定手段は、前記加工電流の電流密度を所定の電流密度以下に設定することを特徴とする請求項7に記載の放電加工装置。 The electric discharge machining apparatus according to claim 7, wherein the machining condition setting means sets the current density of the machining current to a predetermined current density or less.
- 前記加工条件設定手段は、前記電極に供給する加工電流と、前記加工面積又は極間静電容量とに対応する放電パルスを設定する放電パルス設定手段を備えたことを特徴とする請求項8に記載の放電加工装置。 9. The processing condition setting unit includes a discharge pulse setting unit that sets a discharge pulse corresponding to a processing current supplied to the electrode and the processing area or inter-electrode capacitance. The electrical discharge machining apparatus described.
- 前記加工条件設定手段は、前記極間距離の誤差距離αに基づいてジャンプ動作のジャンプ周期とジャンプ量の少なくとも一方を設定するジャンプ動作演算手段を有することを特徴とする請求項4に記載の放電加工装置。 5. The discharge according to claim 4, wherein the machining condition setting unit includes a jump operation calculation unit that sets at least one of a jump cycle and a jump amount of the jump operation based on the error distance α of the distance between the poles. Processing equipment.
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CN (1) | CN102665990B (en) |
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US9950377B2 (en) | 2014-05-30 | 2018-04-24 | National Taiwan Normal University | Plural resistance-capacitance (PRC) electrical discharge machining system |
TWI560013B (en) * | 2014-05-30 | 2016-12-01 | Univ Nat Taiwan Normal | A plural resistance-capacitances (prc) electrical discharge machining system |
JP6598074B2 (en) * | 2016-08-01 | 2019-10-30 | パナソニックIpマネジメント株式会社 | Discharge device and method of manufacturing the same |
JP6734321B2 (en) | 2018-04-25 | 2020-08-05 | ファナック株式会社 | Wire electric discharge machine and electric discharge method |
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JPS5499295A (en) * | 1978-01-23 | 1979-08-04 | Inoue Japax Res Inc | Electrical discharge machining method and apparatus |
JPH08267323A (en) * | 1995-03-30 | 1996-10-15 | Mitsubishi Electric Corp | Electric discharge machining unit |
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JP2914104B2 (en) * | 1993-06-30 | 1999-06-28 | 三菱電機株式会社 | Electric discharge machining method and apparatus, and variable electrostatic capacity and variable inductance applicable to this electric discharge machine |
JP2914102B2 (en) * | 1993-06-30 | 1999-06-28 | 三菱電機株式会社 | Electric discharge machine |
JP3557913B2 (en) * | 1998-09-09 | 2004-08-25 | 三菱電機株式会社 | Electric discharge machine |
JP2002172526A (en) * | 2000-12-11 | 2002-06-18 | Canon Inc | Electric discharge machining method |
US7259347B2 (en) * | 2003-05-20 | 2007-08-21 | Mitsubishi Denki Kabushiki Kaisha | Electric discharge machine that calculates and displays the machining time |
JP4678711B2 (en) * | 2004-03-30 | 2011-04-27 | 株式会社ソディック | Die-sinker EDM |
US7645958B2 (en) * | 2004-10-27 | 2010-01-12 | Mitsubishi Electric Corporation | Electric-discharge-machining power supply apparatus and small-hole electric-discharge machining apparatus |
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---|---|---|---|---|
JPS5499295A (en) * | 1978-01-23 | 1979-08-04 | Inoue Japax Res Inc | Electrical discharge machining method and apparatus |
JPH08267323A (en) * | 1995-03-30 | 1996-10-15 | Mitsubishi Electric Corp | Electric discharge machining unit |
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CN102665990A (en) | 2012-09-12 |
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