JP4510763B2 - Jump control method for electric discharge machine - Google Patents

Description

The present invention relates to a jump control method to that discharge electric machine control jump operation of the machining electrode in order to improve the machining accuracy in the discharge machining with the swinging process.

  In electric discharge machining, generally, a workpiece (workpiece) is placed in a machining tank and immersed in a machining fluid such as insulating oil filled in the machining tank. A machining electrode is placed above the workpiece (workpiece) at a predetermined interval, and electric energy such as a pulse voltage is applied between the machining electrode and the workpiece, that is, between the electrodes to discharge between the electrodes. At the same time, the machining electrode and the workpiece are moved relative to each other by an automatic feed function to perform desired machining on the workpiece. During this discharge, it has been found that not only the workpiece but also the machining electrode is damaged, and this damage increases as the discharge energy increases and when the discharge continues in the same place. At the time of machining, if the machining electrode and the workpiece are too far apart, electric discharge does not occur, and even if the machining electrode and the workpiece are too close to each other, a short circuit occurs and machining becomes impossible. Therefore, the relative movement between the machining electrode and the workpiece is controlled so that the voltage applied between the electrodes is detected and the detected voltage between the electrodes is constant, that is, the machining gap is constant. Done. Here, “relatively moving the machining electrode” in the present specification means that both or one of the workpiece and the machining electrode is moved to move the machining electrode relative to the workpiece, and the workpiece becomes the machining electrode. It also includes moving with respect to it.

  With respect to the relative movement between the workpiece and the machining electrode, the machining electrode is mainly moved along with machining feed which is gradually lowered while repeating minute movements in the vertical direction or the vertical direction (Z-axis direction) as machining progresses. Generally, a swing operation performed in the processing side surface direction (a direction perpendicular to the Z-axis direction) and a jump operation for lifting and returning the processing electrode with respect to the workpiece are performed.

  Oscillation is for moving the machining electrode eccentrically on a small closed path with respect to the workpiece, thereby performing enlargement machining in the machining side surface direction. It is performed by making a relative eccentric motion so as to draw a locus such as. In general, the swing machining performed in this manner is performed simultaneously with the bottom machining of the machining electrode and the enlargement machining with the outer peripheral surface of the side portion. In addition, the jumping operation is performed in order to relatively move the workpiece and the machining electrode mainly in the vertical direction or the vertical direction (Z-axis direction), and to discharge the machining waste generated between the electrodes by the pumping action. . That is, by moving the machining electrode relative to the workpiece mainly in the vertical direction or the vertical direction, and separating the distance between the workpiece and the machining electrode, the machining fluid flows between the workpieces, and then the machining electrode and the workpiece. When the distance between the electrodes is reduced, the machining liquid containing the machining waste is pushed out from the gaps and discharged. Therefore, the moving distance is very large compared with the swinging and machining feed.

  Further, in the rocking process that swings in the machining side surface direction and performs the enlargement process in the machining side surface direction, machining scraps are also generated between the machining side surface and the outer peripheral surface of the side of the machining electrode. It becomes easy to adhere to. Therefore, in order to discharge the processing waste on the processing side surface from between the gaps, a jump operation that causes the processing electrode to be largely separated and approached from the processing side surface is performed in conjunction with a normal jump operation. For example, the machining electrode is moved relative to the workpiece in an oblique direction including the X-axis direction component and the Y-axis direction component together with the Z-axis direction component so that the machining bottom surface and the machining side surface are simultaneously separated and approached. Become. Rather than moving the machining electrode along the machining side in this way, the machining electrode is relatively moved in an oblique direction away from the machining side, thereby machining from the side outer peripheral surface of the machining electrode and the machining side. The effect of discharging waste is obtained.

  By the way, there is a tendency that the effect of discharging the machining waste by such a jump operation increases as the jump speed increases and the stroke increases. Therefore, in the swing machining, it is preferable to increase the angle formed by the machining electrode moving axis and the machining side surface. That is, it is preferable to increase the ratio of the horizontal direction component to the Z-axis direction component of the moving speed of the machining electrode. However, when the angle formed by the movement axis of the machining electrode and the machining side surface is increased, the stroke in the Z-axis direction is reduced, and the discharging action of machining waste due to the jump operation with respect to the machining bottom surface is reduced. In order to solve this problem, the machining electrode moves by combining the movement in the oblique direction and the movement in the Z-axis direction, such as movement in the vertical direction, that is, the Z-axis direction after the movement in the oblique direction. Sometimes done.

As a movement form of the machining electrode combining the movement in the oblique direction and the movement in the Z-axis direction, as described in Patent Document 1, the cycle passes through different paths when jumping up and when jumping down. There are things that jump in shape.
In addition, there are various jumping movements in such a rocking process, but in any case, the position of the machining electrode is made the same at the start of the jump and at the end of the jump. The

JP-A-8-118149 Japanese Patent Publication No. 4-31806

There are some problems when the rocking process as described above is performed.
First, in oscillating machining, as described above, in order to discharge machining waste from the gap between the machining side surface of the workpiece and the side outer peripheral surface of the machining electrode, the horizontal movement component (vertical direction or Z axis) A jump operation including a direction component perpendicular to the direction is performed. The effect of discharging the scraps by jumping increases as the jumping speed increases. However, the higher the speed, the higher the speed, and the vibration by the impact on the inertial force of the electrode or electrical discharge machine at the start point and end point of the jumping movement. Becomes larger. This impact force causes problems such as unpleasant sounds and machine vibration.

  As a solution to this sound or vibration, it is common to reduce the impact force by performing acceleration / deceleration control at the turning point and the start and end points of the jump operation in which vibration occurs. Further, as disclosed in Patent Document 2, there is an electric discharge machining apparatus that switches the moving speed (jump speed) of the machining electrode with respect to the workpiece according to the distance between the workpiece and the machining electrode, and switches to a lower speed when close.

  However, when taking a jump trajectory in which the machining electrode moves in the Z-axis direction after moving in an oblique direction in order to secure a stroke in the Z-axis direction, inertia is similarly applied when switching the movement direction of the machining electrode. Sound and vibration are generated by impact on force. Accordingly, when the relative movement direction is switched during one jump, acceleration / deceleration control is required even before and after the movement direction switching point. In addition, since the electric discharge machining apparatus disclosed in Patent Document 2 switches the speed according to the distance between the workpiece and the machining electrode, the electric discharge machining apparatus cannot be effective against the vibration generated at the jump direction switching point.

  Here, FIG.11 and FIG.12 shows the external view of the machine main body of an electric discharge machine, and demonstrates the vibration of a machine. FIG. 11 is an external view of a so-called ram type electric discharge machine in which the work table 2 is fixed and the machining electrode 15 is moved in the X, Y, and Z axis directions, and FIG. FIG. 2 is an external view of a so-called table moving type electric discharge machine that moves to the Z axis direction and moves the machining electrode 15 in the Z-axis direction.

The machining electrode 15 is moved in the Z-axis direction by moving the main shaft 7 up and down by a Z-axis servomotor disposed in the machine head 6 in any case, so that the moving part is lightweight and moves at high speed. There is little possibility that the machine will vibrate or make an abnormal sound even if you go.
However, when the machining electrode 15 and the workpiece 13 are relatively moved in the horizontal direction, a portion having a large weight is moved in any machine form. For example, in FIG. 11, when moving in the X-axis direction, the saddle 4 is moved by the X-axis servomotor 17, but the saddle 4 is mounted with a combination of the ram 5 and the mechanical head 6, and has a very large weight. Will move. In the movement in the Y-axis direction, the heavy ram 5 and the mechanical head 6 are moved by a Y-axis servomotor (not shown).

Further, in the movement in the X and Y axis directions in FIG. 12, the saddle 9 is moved by the Y axis servo motor 19, and the moving table 8 is moved by the X axis servo motor 17. In this case as well, the movement in the X and Y axis directions moves in a heavy part.
By the way, in the electric discharge machining while performing the jump operation, the time required for the jump operation is shortened when the jump speed is increased, and the machining waste is efficiently discharged from the gap between the machining electrode 15 and the workpiece 13. As described above, the processing efficiency is improved.

  However, when the jump operation is started during the oscillating machining, the machining electrode 15 is in a position eccentric from the machining center axis with respect to the workpiece 13. Accordingly, the side surface of the machining electrode 15 and the workpiece 13 may be close to each other, or the machining electrode 15 may have entered the workpiece 13, and if the machining electrode 15 is lifted as it is, the machining electrode 15 may be damaged, The machining electrode 15 and the workpiece 13 interfere with each other. In order to avoid such an inconvenience, the processing electrode 15 is returned to the center and then lifted, or an ascending jump operation is performed while the processing electrode 15 is returned to the center.

In this way, when a jump operation involving movement in the X-axis or Y-axis direction starts moving at a high speed from the start of the jump operation, a large heavy object moved in the X-axis and Y-axis moves shockingly. Will start or stop, causing the entire machine to vibrate or generate unpleasant abnormal noise.
In addition, when accompanied by a jumping operation in the oblique direction, the moving distance of the moving in the oblique direction with the horizontal movement component is almost shorter than the moving distance in the Z-axis direction, and acceleration / deceleration control is performed in the horizontal direction. It is difficult to secure the necessary distance.

Therefore, it is only necessary to suppress the moving speed of the machining electrode only when the machining electrode moves in the horizontal direction with respect to the workpiece, and the moving speed is suppressed when the machining electrode only performs relative movement in the Z-axis direction. There is no need.
However, when acceleration / deceleration control is performed, the jump speed in a steady state is constant regardless of the direction, and a jump speed is set such that mechanical vibration due to impact force does not become a problem. Further, the acceleration / deceleration control of the moving speed of the machining electrode regardless of the moving direction unnecessarily lengthens the time required for jumping and prolongs the electric discharge machining time.

In addition, as described above, when the jump start point and end point are the same location, abnormal machining due to concentrated discharge is likely to occur, and the workpiece machining surface is damaged or the electrode is consumed, resulting in reduced machining accuracy. A second problem arises.
In order to prevent such deterioration of machining accuracy due to workpiece damage and consumption of the machining electrode, there is a method of suppressing the total discharge energy by extending the pause time of the supplied pulse voltage so that the discharge does not concentrate at the same location. It is used. Accordingly, there is another problem that the machining efficiency is lowered and the machining time is extended because the electric discharge machining amount is reduced accordingly.

  Accordingly, an object of the present invention is to prevent stable concentrated discharge by preventing local concentrated discharge of the machining electrode even when the pulse voltage pause time is reduced in rocking machining performed by electric discharge machining. It is to improve the processing efficiency.

The present invention is, in view of the above object, provides a jump control method of the possible and the discharge electric machine to varying the position on the swing trajectory of the machining electrode before and after the jump operation.

That is, according to the present invention, a jump voltage of an electric discharge machine that applies a pulse voltage between the machining electrode and the workpiece to discharge-machine the workpiece and causes the machining electrode to perform a jump operation in response to a jump request. In the control method, a swing trajectory of the machining electrode with respect to the workpiece is determined, a first position is set as a jump motion start position of the machining electrode on the determined swing trajectory, and the jump motion start position and Except at least a position adjacent to the start position of the jump operation, a second position is set as the end position of the jump operation on the determined swing locus, and the workpiece is discharged while swinging the machining electrode. processing performed, to perform a jump operation from the first position is the start position of the jump operation to the working electrode in response to a jump request during discharge machining And moves down the second of said working electrode to a position that is the end position on the swing trajectory position except adjacent to the position and at least the first position of the first is returned to the electric discharge machining, said rocking The second position is selected and set so as to evenly process all the positions on the movement trajectory, and the electric discharge machining and the jumping operation of the workpiece by swinging are repeated, and the movement trajectory of the machining electrode is determined. There is provided a jump control method for an electric discharge machine that performs control so as to obtain a swing trajectory.

  By setting the end position of the jump operation at a position different from the jump start position during the jump operation of the machining electrode in the swing machining, it is different from the side outer peripheral surface portion of the machining electrode used before the jump operation. The side outer peripheral surface portion is used after the jump operation, and has the effect of discharging the work scraps attached and floating on the side outer peripheral surface portion of the processing electrode used before the jump operation after the jump operation, It has the effect of preventing damage due to continuous concentrated discharge on substantially the same part of the machining electrode before and after the jump operation, and reduces the degradation of machining accuracy due to workpiece damage or machining electrode consumption. It becomes possible.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the main part of an electric discharge machine according to the present invention.
Here, the electric discharge machine shown in FIG. 11 is a so-called ram-type electric discharge machine that fixes the work table 2 and moves the machining electrode 15 in the X, Y, and Z-axis directions. The electric discharge machine shown in FIG. The machine is a so-called table moving type electric discharge machine that moves the work table 3 in the X and Y axis directions and moves the machining electrode 15 in the Z axis direction.

  The electric discharge machine 11 includes a machining electrode 15 for machining a workpiece 13 by electric discharge, an X axis that is a horizontal direction, a Z axis that is a vertical direction, and a Y axis that is a direction perpendicular to both the X axis and the Z axis. X axis feed motor 17, Z axis feed motor 21, Y axis feed motor 19, and each axis feed motor 17, 19, 21 for moving the machining electrode 15 with respect to the three axes And a moving means 25 including a driving means 23 for supplying driving power to 17, 19, and 21. The workpiece 13 is placed in a processing tank (not shown) and is immersed in a processing liquid filled in the processing tank.

  Each of the shaft feed motors 17, 19, and 21 is generally used in combination with a ball screw (not shown), and is connected to the machine head 6 that supports the machining electrode 15 to move the machining electrode 15. In the embodiment shown in FIG. 1, the machining electrode 15 is shown as being moved relative to the workpiece 13 by the moving means 25, but if the machining electrode 15 and the workpiece 13 are relatively movable, The moving unit 25 may move one or both of the head supporting the processing electrode 15 and the work table 3 on which the processing tank is placed as necessary. For example, as shown in FIG. 12, the work table 3 may be moved with respect to the machining electrode 15 by the moving means 25, the head may be moved in the Z-axis direction, and the table may be moved in the X-axis and Y-axis. Good. Moreover, as each axis | shaft feed motor 17,19,21, a servomotor is used suitably.

  As shown in FIG. 1, when the moving means 25 including the respective axis feed motors 17, 19, 21 and a ball screw (not shown) is attached to the head that supports the machining electrode 15, the Z-axis feed motor 21 is machined. The electrode 15 is fed into or retracted from the workpiece 13 in the machining progress direction. The X-axis feed motor 17 and the Y-axis feed motor 19 move the machining electrode 15 in two axial directions orthogonal to each other in a plane perpendicular to the machining progress direction. Thus, the machining electrode 15 can be oscillated two-dimensionally relative to the workpiece 13 by combining the movements by the X-axis feed motor 17 and the Y-axis feed motor 19, and further, the X-axis feed motor 17 and the Y-axis The machining electrode 15 can also be three-dimensionally swung relative to the workpiece 13 by combining the movements by the feed motor 19 and the Z-axis feed motor 21.

  The electric discharge machine 11 is electrically connected to the workpiece 13 and the machining electrode 15, a machining power source 27 that applies electrical energy (voltage or current) between them, and a numerical control unit 29 that controls the operation of the driving unit 23 and the machining power source 27. And further comprising. In the middle of the wiring from the machining power source 27 to the workpiece 13 and the machining electrode 15, a voltage detection means 31 is connected to detect the voltage between the workpiece 13 and the machining electrode 15. By detecting the voltage between the electrodes by the voltage detection means 31, the numerical control means 29 controls the machining gap between the workpiece 13 and the machining electrode 15 so that the voltage between the electrodes is constant.

The numerical control unit 29 includes a machining control unit 33, a jump operation control unit 35, and a swing control unit 37.
The machining control means 33 controls the workpiece 13 and the machining while controlling so that the voltage between the electrodes detected by the voltage detection means 31 is kept constant, that is, keeping the machining gap between the workpiece 13 and the machining electrode 15 constant. The electrode 15 is relatively moved.

  On the other hand, the jump motion control means 35 is configured to move the machining electrode 15 in the Z-axis direction (vertical direction) with respect to the machining bottom surface in order to discharge machining scraps interposed between the workpiece 13 and the machining electrode 15. The processing side surface is reciprocated in the X-axis and Y-axis directions. This reciprocating motion, that is, the jumping operation is not always performed, but is periodically performed by a jump timer, and at this time, the processing is temporarily interrupted.

  Further, the swing control means 37 controls the machining electrode 15 to be eccentrically moved in the machining side surface direction (in a plane perpendicular to the Z-axis direction) with respect to the workpiece 13 along with the above-described vertical movement, Enlargement processing in the lateral direction, that is, swing processing is performed. In the swing machining performed in this way, the machining electrode 15 is moved along a predetermined locus by the swing control means 37. This swing trajectory is typically circular, but a triangle, square, or any other form is employed as needed.

The electric discharge machine 11 of the present invention further includes an input means 39 for inputting a machining command such as a machining program or machining information, and a memory 41 for storing the inputted machining command or the like. A processing condition table is set and stored in the memory 41 in advance.
In one embodiment, the jump motion control means 35 discriminates the jump direction of the machining electrode 15, and the horizontal component in the jump motion direction from the swing locus 43 as shown in FIG. 2A, as shown in FIG. 2A, the machining electrode 15 is caused to perform a jump operation at a jump speed that is lower than the vertical direction component only in the jump operation direction from the swing locus 43. Therefore, when the direction of the jump motion from the swinging trajectory 43 as shown in FIG. 2C is changed halfway, the jump speed is suppressed low while the horizontal direction component is included in the direction of the jump motion, When the horizontal direction component is not included in the direction of the jump operation, the jump speed of the machining electrode 15 is controlled and switched so as to increase the jump speed. This reduces the noise and vibration caused by the impact force due to inertial force at the movement start / end point, the direction switching point, and the turning point that occur when movement including the horizontal direction component is performed, and includes only the vertical direction component. When moving, it is possible to suppress an increase in time required for jumping by moving as fast as possible.

In FIGS. 2B and 2C, the machining electrode 15 performs a jump operation toward one point on the axis extending in the vertical direction through the center of the swing locus 43, but this point is not necessarily passed. There is no need, and there is no need to converge the jump action toward one point.
In other embodiments, as shown in FIGS. 3A to 3C, the jump operation control means 35 controls the operation of the machining electrode 15, and the oscillation of the machining electrode 15 is performed during the oscillating machining. The machining electrode 15 is caused to jump from the jump start position on the movement locus 43, and the machining electrode 15 is lowered and returned to another position on the swing locus 43 that is deviated to some extent from the jump start position. Such a jump operation is repeated, and finally the jump end position is selected and set so that the machining electrode 15 evenly processes all positions on the swing locus 43. By controlling the jump operation in this manner, only a part of the side outer peripheral surface of the machining electrode 15 is not used intensively during the swing machining, and the other part of the side outer peripheral surface is used. In the meantime, there is an effect of discharging the machining waste from the already used portion of the outer peripheral surface of the side portion of the machining electrode 15.

Next, taking as an example the case where the machining electrode 15 moves along a rocking locus 43 such as a circle, the operation during rocking machining in the electric discharge machine 11 of the present invention will be described. Needless to say, the present invention is not limited to the circular swing locus.
FIG. 4 is a flowchart showing the overall flow of electric discharge machining of the electric discharge machine 11 of the present invention.

  First, in step 51, a jump interrupt timer (hereinafter abbreviated as a jump timer), which is one of jump action settings, and machining conditions including the presence / absence of rocking machining are set via the input means 39. The These settings are stored in the memory 41. Here, the description will be made assuming that the rocking process is performed. The setting of the jump timer includes a jump cycle when the jump operation is periodically performed, a set voltage when the jump operation is performed when the voltage between the electrodes becomes equal to or lower than the set voltage, and the like.

After all necessary settings have been made, electric discharge machining is started in step 53. At this time, swing machining, which is enlargement machining in the side surface direction of the machining electrode 15, is performed together with electric discharge machining performed in the vertical direction.
While the electric discharge machining is being performed, the jump timer shown in step 55 is sequentially interrupted according to the jump operation cycle and the set voltage set in step 51. This jump timer interrupt will be described in detail later.

  While electric discharge machining is being performed, the voltage detection means 31 further detects and smooths the voltage between the electrodes (step 57), and the smoothed voltage between the electrodes is compared with a preset reference value ( Step 59). If this is higher than the reference value, the Z-axis feed motor 21 is driven via the drive means 23, and the machining electrode 15 is relatively advanced toward the workpiece 13 (step 61). If this is lower than the reference value, the Z-axis feed motor 21 is driven via the drive means 23 to relatively retract the machining electrode 15 from the work 13 (step 63). The amount of retraction is determined by the machining control means 33 of the numerical control means 29 according to the difference between the reference value and the detected value of the interelectrode voltage. In the forward and backward movements, in the case of oscillating machining, the eccentric movement of the machining electrode 15 is also performed at the same time, and the X-axis and Y-axis feed motors 17 and 19 are driven via the driving means 23 to decenter the machining electrode 15. A horizontal swing is also made by moving the amount forward or backward.

The above steps 55 to 63 are continued until the machining electrode 15 reaches the machining completion position (step 65).
Steps 53 to 65 except for step 55 are performed by the machining control means 33 with respect to the feed of the machining electrode 15 in the vertical direction, that is, machining feed, and the feed with respect to the feed of the machining electrode 15 in the horizontal direction, that is, rocking with respect to the oscillation. This is performed by the motion control means 37. On the other hand, step 55 is performed by the jump operation control means 35.

Next, the form of step 55 of jump timer interruption, which is the subject of the present invention, will be described in detail.
FIGS. 5 and 6 are flowcharts of the operation relating to the first embodiment of the electric discharge machine 11 of the present invention in which the jump operation control means 35 is configured to control the speed of the jump operation according to the direction of the jump, FIG. 7 is a more detailed flowchart of the steps for setting or changing the jump direction shown in FIGS.

  The form of jump operation of the machining electrode 15 is designated in advance in step 51 of FIG. In this jump operation mode, the machining electrode 15 jumps in the vertical direction, that is, the Z-axis direction as shown in FIG. 8A, and the machining electrode 15 moves in the X-axis as shown in FIG. 8B. Jumping in an oblique direction including the direction component and the Y-axis direction component together with the Z-axis direction component, as shown in FIG. 8 (c), after first moving in the oblique direction, the direction is changed to jump in the Z-axis direction. As shown in FIG. 8 (d), it is similar to FIG. 8 (c), which combines the movement in the oblique direction and the movement in the Z-axis direction. A form of jumping in a cycle through the passing point is included. Among these jump forms, those that include a change in the jump direction include a method in which a point that passes in the middle is specified in addition to the jump top dead center position that is normally specified, and the swing central axis is defined as a halfway passing point. A jump route designation method or the like can be adopted. Further, in the case of a jump configuration as shown in FIGS. 8C and 8D, the machining electrode 15 does not necessarily have to move on an axis passing through the swing center of the swing track 43.

Below, the operation | movement of 1st embodiment of the electric discharge machine 11 of this invention is demonstrated by making into an example the thing in which the change of a jump direction is included among the said jump forms.
When the jump timer is interrupted in step 55 of FIG. 4, the direction and speed of the jump operation are set in step 67 according to the designated jump operation mode, and in step 69, the numerical control means 29 uses the machining power supply. Application of electrical energy from 27 to the work 13 and the machining electrode 15 is temporarily stopped, and a jump operation is started. The setting of the direction and speed of the jump operation in step 67 will be described in detail later.

  Next, in step 71, the machining electrode 15 is moved relative to the workpiece 13 by the moving means 25 in accordance with the jump direction and speed set in step 67. At this time, the relative position of the direction change position with respect to the jump start position of the machining electrode 15 is determined in advance according to the form of the jump operation. The machining electrode 15 continues to move at the speed and direction set in step 67 until the machining electrode 15 reaches a predetermined direction change position (step 73).

If a jump form in which the direction is not changed, for example, a jump form as shown in FIGS. 8A and 8B is selected, the process proceeds according to a route indicated by a dotted line 75.
When the jump direction change position is reached, the jump direction and speed are set again in step 77. In step 79, the moving means 25 applies the workpiece 13 to the work 13 until the turn point is reached according to the set jump direction and speed. The processing electrode 15 is relatively moved. When the machining electrode 15 reaches the turning point (step 81), the command data of speed and direction are all multiplied by (-1), and the moving direction and speed vector are inverted and set (step 83).

  Hereinafter, similarly, the machining electrode is moved by the moving means 25 according to the set jump direction and speed until the machining electrode 15 reaches a predetermined direction changing position (step 85), and the machining electrode 15 is moved to the direction changing position. (Step 87), the jump direction and speed are set again and the jump direction is changed (step 89). Next, the machining electrode 15 is moved by the moving means 25 according to the set jump direction and speed until the machining electrode 15 reaches the jump start position (step 91). If it is determined in step 93 that the machining electrode 15 has reached the jump start position, the jump operation is terminated and the jump timer is reset (step 95).

When the jump form in which the direction is not changed is selected, the process proceeds along the dotted line 97 as in the case described above.
Hereinafter, the procedure for setting the jump direction and speed performed in steps 67, 77, and 89 in FIGS. 5 and 6 will be described in more detail with reference to the flowchart in FIG.

First, in step 97, the jump direction is set according to the form of the jump operation designated in advance. If a jump operation has already been performed, that is, in the case of steps 77 and 89, the setting of the jump direction is changed in step 97.
Next, in step 99, it is determined whether the set jump direction includes an X-axis direction component or a Y-axis direction component. When the machining electrode 15 moves only in the Z-axis direction in the jump operation mode of FIG. 8A or the jump operation mode of FIGS. 8C and 8D, the process proceeds to step 101. On the other hand, in the jump operation mode of FIG. 8B and the jump operation modes of FIG. 8C and FIG. 8D, the X-axis direction or the Y-axis direction, such as when the machining electrode 15 moves obliquely, etc. When the movement to is included, the process proceeds to step 103.

When the process proceeds to step 101, the jump speed is determined to a predetermined relatively high speed J1 applied in the case of only the Z-axis direction component.
When the process proceeds to step 103, components related to the XY plane (the plane formed by the movement of the X-axis component and the Y-axis component, that is, the plane perpendicular to the Z-axis) of the direction vector of the jump operation are Desired. This XY plane component is an orthogonal projection of the direction vector with respect to the XY plane.

Next, a ratio between the magnitude of the XY plane component of this direction vector and the magnitude of the Z-axis direction component is obtained, and the jump speed is determined according to this ratio (step 105 and step 107). In step 109, the determined jump speed is set in the jump operation control means 35.
Specifically, a jump speed J2 at which the machining electrode 15 moves in the XY plane direction (direction perpendicular to the Z axis) is determined in advance, and Z is determined according to the ratio α of the Z axis direction component to the XY direction component of the jump direction vector. The jump speed in the axial direction is defined as αJ2, and the jump speed as a whole is determined as J2 × √ (1 + α ² ) accordingly, and this is set in the jump control means 35. Preferably, the jump speed J2 in the XY plane direction is lower than the jump speed J1 applied when the machining electrode 15 moves in the direction of only the vertical direction component, and the relative movement start / stop point and direction of the machining electrode 15 The sound and vibration generated in the electric discharge machine 11 at the switching point and the turning point are set so as to be suppressed to an appropriate level.

Therefore, if the jump operation mode or jump direction is set in step 51, the operator does not need to set a jump speed according to the jump operation mode or jump direction, and an appropriate jump speed according to the jump direction. Is automatically set.
Further, when the jump direction is switched as shown in FIGS. 8C and 8D, a jump speed suitable for the jump direction at that time is automatically set, and only in the Z-axis direction. When the machining electrode 15 is relatively moved, a jump operation is performed at a relatively high jump speed, and when the movement includes a horizontal component, the jump operation is performed at a jump speed set so that the horizontal component of the movement speed is low. The vibration of the electric discharge machine 11 at the start / stop point, the direction switching point, and the turning point of the machining electrode 15 is reduced.

  Alternatively, when the movement of the machining electrode 15 by the jump operation includes a horizontal component, the jump speed J2 ′ may be set regardless of the jump direction instead of steps 103, 105, and 107 ( However, when the movement of the machining electrode 15 by the jump operation is only the Z-axis direction component, the jump speed is set to J1). In this case, the jump speed J2 ′ is the impact sound of the electric discharge machine 11 generated at the start / stop point, the direction switching point, and the turning point of the machining electrode 15 when the jump operation is assumed to include only the horizontal component. It is preferable to set it low enough that vibration and vibration do not cause discomfort.

Similarly, the ratio of the XY plane direction component and the Z-axis direction component of the direction vector can be divided into several stages, and the same jump speed J2 ′ can be set in each section.
Also, any other method that allows different jump speeds to be set depending on the jump direction can be used.

  FIG. 9 shows the operation of the electric discharge machine 11 according to the second embodiment of the present invention which constitutes the jump operation control means for setting the end position of the jump operation at a position shifted from the jump start position in the swing trajectory of the machining electrode. FIG. 10 is a flowchart showing the step of setting the jump end position shown in FIG. 9 in more detail.

When the jump timer is interrupted in step 55 of FIG. 4, the application of electrical energy from the machining power source 27 to the workpiece 13 and the machining electrode 15 is temporarily stopped by the numerical control means 29 in step 111, and the direction of the jump operation Then, the speed is set and the jump operation is started.
Next, in step 113, the machining electrode 15 is moved relative to the workpiece 13 by the moving means 25 according to the jump direction and speed set in step 111, that is, a jump operation is performed. At this time, the relative position of the return position with respect to the jump start position of the machining electrode 15 is determined in advance. The machining electrode 15 continues to move until the machining electrode 15 reaches a predetermined folding position (step 115).

When the return position is reached, a jump end position different from the jump start position is set at step 117, and the jump direction and speed are set again accordingly. The end position is selected as far as possible from the jump start position. The selection of the end position will be described later in detail.
In step 119, according to the set jump direction and speed, the machining means 15 is moved relative to the work 13 by the moving means 25 until the jump end position is reached. If it is determined in step 121 that the machining electrode 15 has reached the end position, the jump operation ends in step 123, and the jump timer is reset. At the same time, the application of electrical energy from the machining power source 27 to the workpiece 13 and the machining electrode 15 is resumed.

Hereinafter, the procedure for selecting the end position of the processing electrode 15 performed in step 117 of FIG. 9 will be described in more detail with reference to the flowchart of FIG.
First, end point candidate points are created by equally dividing the preset swing locus 43 of the processing electrode 15 by a predetermined number. When the jump motion is started, the jump motion control means 35 refers to the created jump end position candidate point in step 125.

Next, it is determined in step 127 whether or not all the candidate points at the jump end position have been used. If all candidate points have been used, all the candidate points at the end position that have been used are cleared in step 129. The candidate points are initialized so that they are treated as unused points.
If any candidate point is treated as unused, the process proceeds to step 131, and a candidate point at an end position that is somewhat distant from the start position of the jump operation in progress is selected. By selecting an end position that is somewhat distant from the start position of the jump operation, the part used in the swing machining of the side outer peripheral surface of the machining electrode 15 before and after the jump becomes different. While the electric discharge machining is performed using the outer peripheral surface portion, there is an effect that the machining waste is discharged from the side outer peripheral surface portion used before the jump operation, and the work 13 is damaged and the machining electrode 15 is consumed. It becomes possible to suppress.

  In step 133, it is confirmed whether or not the selected candidate point has been used. If the candidate point has been used, the process returns to step 131 again to select a candidate point. If it is confirmed that a candidate point that can be treated as unused is selected, the servo block is changed in step 135 to change the jump end position. In this servo block, start point information and end point information relating to movement are set, and by changing this information, the machining electrode 15 moves to a new jump end position, and the setting of the jump end position is completed.

By continuing the jump operation in this way, all the candidate points of the end position on the swing locus 43 of the machining electrode 15 are selected evenly. Therefore, the swing machining is performed on the workpiece 13 on the swing locus. On the other hand, it will be performed equally.
The swing locus 43 is equally divided, and each section can be configured as a very small one, that is, a point.

These jump operations are controlled by the numerical control means 29, mainly the jump operation control means 35.
Although the two forms of the jump operation control means shown above are shown as different forms, it is needless to say that this can be carried out simultaneously.

  As described above, according to the present invention, in the swing machining, the jump speed can be automatically changed according to the direction of the jump operation, and therefore when the movement of the machining electrode includes a horizontal component, the speed is increased. It is possible to improve the machining accuracy by suppressing the horizontal component to a low level, reducing unpleasant sounds and vibrations of the electric discharge machine generated at the start / stop point of the machining electrode, the direction switching point, and the turning point.

  In addition, by changing the position of the machining electrode on the swinging trajectory before and after the jump operation, the concentrated discharge that occurs continuously by electrical discharge machining only at a specific part of the machining electrode is avoided, and the part used before the jump operation It is possible to suppress the damage of the workpiece and the consumption of the machining electrode by producing the effect of discharging the machining waste after the jump operation. By suppressing the damage of the workpiece and the consumption of the machining electrode, the machining accuracy can be improved.

  Furthermore, since it is possible to give a large electrical energy to the machining electrode, there is an effect that the machining time can be shortened.

It is a block diagram which shows the principal part of the electric discharge machine of this invention. It is a schematic diagram for explaining that the jump operation control means controls the jump operation of the machining electrode so as to change the jump speed according to the jump direction. It is a schematic diagram for explaining that the jump operation control means controls the jump operation of the machining electrode so as to change the position of the machining electrode before and after the jump operation. It is a flowchart which shows the whole flow of the electric discharge machining of the electric discharge machine of this invention. It is the first half part of the flowchart of the operation | movement regarding the 1st embodiment of the electric discharge machine of this invention which comprised the jump operation control means so that the speed of jump operation might be controlled according to the direction of a jump. FIG. 6 is the latter half of the flowchart shown in FIG. FIG. 7 is a more detailed flowchart of steps for setting or changing the jump direction shown in FIGS. 5 and 6. FIG. It is a diagram which shows some forms of jump operation | movement. It is the flowchart of the operation | movement regarding the 2nd embodiment of the electric discharge machine of this invention which comprised the jump operation control means which sets the end position of jump operation in the position away from the jump start position in the rocking locus of a machining electrode. FIG. 10 is a more detailed flowchart of steps for setting a jump end position shown in FIG. 9. FIG. It is an external view of a ram type electric discharge machine. It is an external view of a table moving type electric discharge machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Electric discharge machine 13 Work 15 Processing electrode 25 Moving means 33 Processing control means 35 Jump operation control means 37 Swing control means

Claims (1)

In the electric discharge machine jump control method of applying a pulse voltage between the machining electrode and the workpiece to perform electric discharge machining of the workpiece and causing the machining electrode to perform a jump operation in response to a jump request,
Determine the swing trajectory of the machining electrode with respect to the workpiece,
A first position is set as a start position of the jumping operation of the machining electrode on the predetermined swing locus,
Except for the start position of the jump operation and at least the position adjacent to the start position of the jump operation, a second position is set as the end position of the jump operation on the determined swing locus;
Electrifying the workpiece while swinging the machining electrode,
In response to a jump request at the time of electric discharge machining, the machining electrode is caused to perform a jump operation from a first position which is a start position of the jump operation, and the first position and at least a position adjacent to the first position are determined. Lowering the machining electrode to the second position, which is the end position on the swing trajectory removed, and returning to electrical discharge machining ,
The second position is selected and set so as to evenly process all the positions on the swing trajectory, and the electric discharge machining and the jump operation of the workpiece by the swing are repeated, and the movement trajectory of the machining electrode is A jump control method for an electric discharge machine, wherein the control is performed so that the predetermined swing locus is obtained.

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