JP2000084743A5 - - Google Patents

Description

0007
[Means for solving problems]
Invention as defined in claim 1 is intermittently discharged is relatively moved at a preset feed rate while caused between the wire electrode and the workpiece to between the wire electrode and the workpiece, first In the wire-cut discharge processing method in which the corner portion in the cut is processed, the feed speed is made smaller than the preset feed speed by the time the corner portion is reached, and the discharge energy is obtained under the initial electromachining conditions. to be smaller than the energy of the discharge is, after by the relative movement discharge reaction force applied to at least the wire electrode to a predetermined position where the opposite direction the against the direction of relative movement of the wire electrode feed speed Is gradually returned to the preset feed rate and the discharge energy is increased so as to return to the discharge energy obtained under the initial electroprocessing conditions.

In this way, at the corner points of the corner section, the relative feed speed of the wire electrode is gradually slowed down or paused from the initially set relative feed speed while the discharge processing is continued by applying the machining voltage pulse. and the discharge energy by, for example, set low frequency of discharge is decreased from the initial value to reduce the discharge reaction force, discharge reaction force further while reducing the relative feed speed of the wire electrode against the relative movement direction Since the discharge processing is performed so that the relative feed rate and the discharge energy are returned to the initial values after the directions are opposite to each other, there is almost no deviation in the processing shape of the corner portion, and the accuracy of the processing shape is greatly improved. It becomes possible to make it.

That is, since the pulse discharge frequency is lowered at the curved corner portion to reduce the relative feed rate of the wire electrode, the processed shape of the curved corner portion is hardly deviated, and the accuracy of the processed shape is improved. It can be greatly improved. In this case, the predetermined position is a position where the wire electrode is sandwiched between the machined grooves formed in the work piece. Further, as defined in claim 2 , the predetermined position is set to a position separated from the corner point by a distance L represented by the following equation.
L = (Data C-Corner R) (1 / sinθ + 1 / tanθ) + Data D
However, the data C is the sum of the radius of the wire electrode and the discharge gap, the corner R is the radius of the corner, θ is the angle of the corner, and the data D is the delay amount of the wire electrode.

Further, as defined in claim 3 , with respect to the discharge energy, the discharge energy is obtained under the initial electrical processing conditions by lengthening the discharge pause period and reducing the discharge frequency. Try to be smaller than . Further, as defined in claim 4, when the corner portion is an edge-shaped corner, the relative movement is stopped for a predetermined time preset at the corner point.

In each of the above inventions, as defined in claim 5 , the pressure or flow rate of the machining fluid jet set in advance at the corner portion is reduced, and after reaching at least the predetermined position, the pressure or flow rate is reached. by gradually to increase to return to the preset pressure or flow, the vibration of the wire electrode can be suppressed, it is possible to improve the accuracy of even the machined shape.

Further, the inventions defined in claims 6 and 7 are device inventions for carrying out the above method invention, the power supply device for intermittently applying a processing voltage pulse between the wire electrode and the workpiece, and the wire electrode. In a wire-cut discharge processing apparatus provided with a relative moving device for relatively moving the workpiece and the workpiece at a preset feed rate, the feed rate is set in advance before reaching the corner portion at the corner portion in the first cut. so as to be smaller than the set feed speed, later moved relative discharge reaction force applied to at least the wire electrode to a predetermined position where the opposite direction the against the direction of relative movement of the wire electrode, said feed The relative movement control device that controls the relative movement device so as to gradually return the speed to the preset feed speed, and the frequency of the processing voltage pulse to be lower than the initial frequency by the time the corner portion is reached. back discharge reaction force applied to at least the wire electrode until the later against the direction of relative movement reaches a predetermined position which is in the opposite direction, of gradually the initial frequency of the machining voltage pulse frequency of the wire electrode As described above, the pulse control device for controlling the power supply device is provided.

Next, when the guides 4 and 6 reach the corner point X2 and the relative feed rate of the wire electrode 2 becomes zero (time t1), the jet pressure of the machining fluid is set low and the frequency is set to the minimum f4. It is set small and this state is maintained for a predetermined time T1. Here, the jet pressure is also set to the minimum value in order to prevent unnecessary vibration from being generated in the wire electrode 2. As a result, the processing energy is reduced to the minimum value, and during this predetermined time T1, electric discharge is performed between the wire electrode 2 and the workpiece W as described with reference to FIGS. 12 and 13. The bending of the wire electrode 2 is removed, and the wire electrode 2 at the center of processing is located directly below the guide 4 (see FIG. 13). That is, in FIG. 2, the wire electrode 2 at the center of processing is freed from bending and reaches the point X2.

In the above embodiment, the case of machining the edge-shaped corner portion 54 whose machining progress direction is bent at an acute-angled shape, a right-angled shape, or an obtuse-angled shape has been described as an example. It can also be applied when processing. FIG. 8 is a diagram showing a processing locus when processing a curved corner portion 56 having a radius R, and FIG. 9 is a diagram showing a jet pressure of a processing liquid when processing a corner portion shown in FIG. 8 and a relative feed rate of the wire electrode 2. It is a figure which shows the relationship of the frequency of a voltage pulse. As shown in FIG. 8, points X11 to X13 have an arc shape with a radius R (unlike edge-shaped corners, they are formed by a machining program), and since there are no corners in the machining locus here, there are no corners. A processing method in which there is no state in which the relative movement between the times t1 to t2 in FIG. 3 is stopped is adopted. That is, when the position of the wire electrode 2 reaches the point X10 immediately before entering the curved corner portion 56, the relative feed rate of the wire electrode 2 (see FIG. 9B) is gradually reduced to the point X11. To arrive. However, in the case of this embodiment, unlike the case shown in FIG. 3, the relative feed rate is not set to zero as described above, the jet pressure of the machining fluid is maintained at the set value, and the frequency of the voltage pulse is further increased. Is maintained at the set value f0.

Claims (7)

A wire that processes the corner portion in the first cut by causing relative discharge between the wire electrode and the workpiece at a preset feed speed while intermittently generating discharge between the wire electrode and the workpiece. In the cut electrical discharge machining method, the feed rate is gradually made smaller than a preset feed rate before reaching the corner portion , and the discharge energy is smaller than the discharge energy obtained under the initial electrical machining conditions. and so on, after by relatively moving the wire electrode discharge reaction force applied to at least the wire electrode to a predetermined position where the opposite direction the against the direction of relative movement of the wire electrode, the preset feed speed gradually And the discharge energy is increased to return to the discharge energy obtained under the initial electromachining conditions. Wire-cut electric discharge machining method being characterized in that as. The wire-cut electric discharge machining method according to claim 1, wherein the predetermined position is a position away from the corner point by a distance L represented by the following expression.
L = (data C−corner R) (1 / sin θ + 1 / tan θ) + data D
However, data C is the sum of the radius of the wire electrode and the discharge gap, corner R is the radius of the corner, θ is the angle of the corner, and data D is the delay amount of the wire electrode. 2. The discharge energy is made smaller than the discharge energy obtained under the initial electromachining conditions by increasing the discharge rest period and decreasing the discharge frequency. The wire-cut electric discharge machining method described. The wire-cut electric discharge machining method according to any one of claims 1 to 3 , including stopping the relative movement for a predetermined time at the corner point when the corner portion is an edge-shaped corner. . The pressure or flow rate of the machining fluid jet set in advance in the corner portion is reduced, and after reaching at least the predetermined position, the pressure or flow rate is gradually returned to the preset pressure or flow rate. The wire-cut electric discharge machining method according to claim 1 , wherein the wire-cut electric discharge machining method is increased. A power supply device that intermittently applies a machining voltage pulse between the wire electrode and the workpiece, and a relative movement device that relatively moves the wire electrode and the workpiece at a preset feed speed. In the wire cut electric discharge machining apparatus, the feed rate is gradually made smaller than a preset feed rate before reaching the corner portion at the corner portion in the first cut , and at least the discharge reaction force applied to the wire electrode is after are relatively moved to a predetermined position where the opposite direction against the direction of the relative movement of the wire electrode, the gradually preset relative movement control for controlling the relative movement device back to the feed speed of the feed rate a device, and the frequency of the machining voltage pulses to reach the corner portion so as to be lower than the initial frequency, at least the word After discharge reaction force applied to ya electrode has reached a predetermined position which is in the opposite direction the against the direction of relative movement of the wire electrode, to return to the frequency gradually in the initial frequency of the machining voltage pulses, A wire-cut electric discharge machining apparatus comprising a pulse control device for controlling the power supply device. The wire cut according to claim 6 , wherein the pulse control device includes a configuration for controlling the frequency of the machining voltage pulse by increasing / decreasing an off time of a gate pulse for turning on / off at least one switching element included in the power supply device. Electric discharge machine.