JPH09108945A - Electric discharge machining device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To put into practice of lateral finishing of a subject substance with high precision without frequently replacing electrodes by practicing lateral finish machining by the lateral finishing quantity of the subject substance at the bottom of a machining electrode cylinder. SOLUTION: An electrode moving means 3 slides a thin wall pipe electrode 1 to the outside by or more than the thickness 't' from the lateral unfinished portion 13 to the finished direction of a subject substance 2 and moves it along the lateral periphery of the subject substance 2. As moving it in such a manner, a certain width 'w' of the unfinished portion 13 is machined so as to remove it by a certain depth by the bottom of the thin wall pipe electrode 1. While machining is practiced by the thin wall pipe electrode 1, the thin pipe electrode 1 is rotated by centering the cylinder shaft. Thus lateral machining is precisely practiced by using the thin wall pipe electrode 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining apparatus and an electric discharge machining method for side surface finishing of a workpiece.

[0002]

2. Description of the Related Art When machining a workpiece by electric discharge machining, rough machining is performed by electrical conditions for rough machining at the beginning of machining in order to perform accurate machining while maintaining an improvement in machining speed. (Hereinafter, referred to as primary processing), a method of gradually switching to electrical conditions for finishing processing can be considered.

Specifically, as shown in FIG. 5, for example, electric discharge machining is performed by the bottom surface of the electrode in the depth direction of the workpiece. At this time, as the machining of the workpiece in the depth direction progresses, the electrical condition of the electrode is gradually switched from the electrical condition for rough machining to the electrical condition for finish machining. Switching to electrical conditions for finishing can be performed by shortening the current pulse width or reducing the current peak value.

In this case, although the bottom surface of the work piece is finished with high accuracy, the side surface remains rough according to the electrical conditions when the surface is formed, as shown in FIG. 5 (b). Resulting in. Therefore, it is necessary to finish the side surface of the work piece by some method.

As the first method, "Mitsumitsu Tsuchiya et al., Three-dimensional controlled electric discharge machining with a cylindrical electrode (1st report) -The changing process of the electrode shape in the groove machining-, Journal of the Institute of Electrical Processing, Vo.
l. 17, No. 33 (1983) 31 ”, a method of performing side surface finishing can be considered. In this method, as shown in FIG.
In this method, the side surface of No. 1 is used to perform side surface finishing by lateral processing.

However, in this case, the side surface of the electrode is shown in FIG.
As described above, the shape of the side surface of the workpiece is also transferred accordingly. Therefore, although the surface roughness is large due to the primary processing, in terms of shape, a large amount of shape error occurs in the vertical surface processed with high accuracy.

In order to reduce the electrode consumption as much as possible, it is possible to machine only the side surface machining under the condition of low electrode consumption, but if the contour side surface outer circumference becomes long and the finishing machining amount per electrode becomes large. Accordingly, the amount of consumption of the electrodes inevitably increases accordingly, and the shape of the consumption of the electrodes tends to be the same as in FIG. 26 (a) described above. Therefore, in order to perform processing while maintaining the shape accuracy of the electrodes, the electrodes must be frequently replaced every time the consumption of the electrodes exceeds the allowable consumption.

As a second method, "Chiyo Tomoko et al., Electrode wear simulation in die-sinking EDM, 199.
Proc. 5th Spring Meeting of the Japan Society for Precision Machining Proceedings, p98
1 ”,“ Masanori Kunieda et al., Workpiece shape simulation in die-sinking EDM, Journal of the Institute of Electrical Processing, Vol. 287,
No. 59 (1994) 21 ”, a method of performing side surface finishing can be considered.

In this method, as shown in FIG. 26 (b), the cylindrical electrode 11 is moved in the depth direction of the workpiece, and the bottom surface of the electrode is used for side surface finishing. In this case, since the portion to be scraped off by the side surface finishing (hereinafter referred to as the side surface finishing portion) is very thin compared to the electrode diameter, the electrode is slid only on the side surface finishing portion for processing.

However, in this case, since the cross-sectional area of the electrode related to machining is very small compared to the bottom area of the electrode, the electrode is consumed rapidly, and the machining gap between the electrodes is different in the machined portion. The electrical consumption ratio of each part varies.

Generally, the electrode wear increases at the corners and ridges. Further, the consumption is small in the portion where the inclination with respect to the electrode feeding direction is large. This is because the removal volume of the work piece per unit area of the electrode is different. When the other conditions are the same, the electrode consumption ratio becomes a function of the machining gap with the workpiece, and the electrode consumption rate decreases as the machining gap increases. Therefore, the side surface portion has a larger working gap with the work piece than the corner portion of the bottom portion of the cylindrical electrode, and therefore wear is reduced.

As a result of electrode consumption due to the above reasons,
Also in the second method described above, the side surface of the electrode has an oblique shape as shown in FIG. Therefore, it is also difficult to realize the machining while maintaining the highly accurate shape. Therefore, in order to maintain the shape accuracy, the electrodes must be frequently replaced every time the consumption of the electrodes exceeds the allowable consumption.

[0013]

For the above reason, when the side surface finishing is performed by the above-mentioned first method and second method, the electrode consumption is non-uniform, so that the side surface is highly accurate. It was difficult to finish. Further, in order to perform highly accurate side surface finishing by the above-mentioned first method or second method, the electrodes had to be frequently replaced every time the consumption amount of the electrodes exceeded the allowable consumption amount.

Therefore, a first object of the present invention is to perform side surface finishing of a workpiece with high accuracy without frequently changing electrodes. A second object is to suppress the corner radius formed between the side surface of the work piece and the bottom surface of the work piece in contact with the side surface to be equal to or less than the required accuracy. A third object is to perform taper finishing of a work piece with high accuracy without frequently changing electrodes. A fourth object is to accurately finish the side surface finishing processing or the taper finishing processing.

[0015]

An electric discharge machining apparatus according to the present invention comprises a machining electrode having a cylindrical shape having a wall thickness equal to or less than a side surface finishing amount of a workpiece, the machining electrode and the workpiece. A power supply for applying a voltage between them, a rotating means for relatively rotating the machining electrode with respect to the workpiece about the axis of the cylinder, and a relative movement of the machining electrode with respect to the workpiece. And a control means for controlling relative movement of the processing electrode by the movement means,
The side surface finishing of the side surface finishing amount of the workpiece is performed by the bottom surface of the cylinder of the processing electrode.

Further, a disk-shaped working electrode, a power supply for applying a voltage between the working electrode and the workpiece,
Rotating means for rotating the machining electrode relative to the workpiece relative to the axis of the disk, and X-axis for aligning the machining electrode along the side surface of the workpiece with respect to the workpiece. Relative movement in the direction, relative expansion movement in the Y-axis direction orthogonal to the X axis and approaching the side surface of the workpiece, and Z axis orthogonal to both the X and Y axes depending on the thickness of the disc-shaped electrode. Having a moving means for relatively moving in a direction and a controlling means for controlling relative movement of the machining electrode by the moving means, and performing side surface machining of the workpiece by a circumferential side surface portion of the machining electrode. Is.

Furthermore, a disk-shaped electrode having a thickness not more than twice the desired corner radius of the corner formed between the side surface of the workpiece and the bottom surface of the workpiece in contact with the side surface is provided. I have.

A cylindrical machining electrode having a wall thickness equal to or less than the taper finishing amount of the workpiece, a power source for applying a voltage between the machining electrode and the workpiece, and the workpiece. On the other hand, rotation means for relatively rotating the machining electrode about the axis of the cylinder, moving means for relatively moving the machining electrode with respect to the workpiece, and taper side surfaces of the workpiece. Tilting means for tilting the working electrode in the direction in which the cylindrical side surface of the working electrode contacts, and control means for controlling relative movement of the working electrode by the moving means and tilting of the working electrode by the tilting means. In addition, the cylindrical bottom portion of the machining electrode is used to perform taper finishing by the taper finishing amount of the workpiece.

Moving speed measuring means for measuring the moving speed of the machining electrode; moving speed comparing means for comparing the moving speed measured by the moving speed measuring means with a reference value;
Based on the comparison result by the moving speed comparison means, it has a determination means for determining whether or not the side surface processing of the workpiece by the processing electrode is completed.

In the electric discharge machining method according to the present invention, a cylindrical machining electrode having a wall thickness equal to or less than the side surface finishing amount of the workpiece is moved relative to the workpiece, and the workpiece is attached to the workpiece. On the other hand, the surface of the cylinder is rotated relative to the axial center of the cylinder, and the bottom surface of the cylinder of the machining electrode performs side surface finishing by the amount of side surface finishing of the workpiece.

A disk-shaped electrode is attached to the workpiece.
Relative rotation about the axis of the disc and relative movement in the X-axis direction along the side surface of the workpiece, relative expansion movement in the Y-axis direction orthogonal to the X axis and approaching the side surface of the workpiece. , Relative to the thickness of the disk-shaped electrode in the first direction of the Z-axis orthogonal to both the X-axis and the Y-axis, and the side surface of the workpiece is processed by the circumferential side surface of the disk-shaped electrode. After the first machining step, the disk-shaped electrode is rotated relative to the workpiece relative to the axis of the disk, and in the X-axis direction. Relative movement, relative expansion movement in the Y-axis direction with an expansion amount smaller than the expansion amount in the first processing step,
A second processing step of performing relative movement in the second direction of the Z-axis according to the thickness of the disk-shaped electrode, and performing side surface processing of the workpiece by the circumferential side surface of the disk-shaped electrode. I have.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. This embodiment relates to an electric discharge machining apparatus for performing side surface machining with a thin pipe electrode having a specific wall thickness, which will be described below with reference to FIGS. FIG.
FIG. 1 is an overall view of an electric discharge machine according to this embodiment.

In FIG. 1, reference numeral 1 is a thin-walled pipe electrode for side surface finishing, and 2 is a workpiece to be subjected to electric discharge machining.
3 is an electrode moving means for rotating the thin-walled pipe electrode 1 about the axis of the thin-walled pipe electrode 1 and moving the thin-walled pipe electrode 1 according to the machining shape data, and 4 is a working fluid stored in a working tank 5 described later. . Reference numeral 5 denotes a processing tank. The processing liquid 5 is stored in the processing tank 5, and the workpiece 2 is immersed in the processing liquid 4.

Reference numeral 6 is a processing liquid supply means for circulating the processing liquid 4 stored in the processing tank 5, and 7 is a thin pipe electrode 1
A machining power supply for applying a current pulse between the workpiece 2 and the workpiece 2. Reference numeral 8 denotes an NC control unit that controls the electrode moving means 3 so as to move the thin pipe electrode 1 based on the processed shape data.

FIG. 2 is a diagram showing the flow of information in the NC control unit 8. In FIG. 2, reference numeral 81 denotes a machining contour shape path 81a indicating a contour shape to be machined, a side surface finishing amount 81b,
It is a storage unit that stores data such as the side surface orientation 81c with respect to the electrode traveling direction.

The machining contour shape path is a two-dimensional electrode diameter path representing the target machining shape as shown in FIG. The direction of the side surface with respect to the traveling direction means, for example, FIG.
The right direction in (b), that is, the direction toward the side surface of the workpiece.

Reference numeral 82 is a conversion means for enlarging or reducing the contour shape path 81a in the lateral direction by the finishing amount based on the data in the storage means 81. The conversion means 82 converts the coordinate data 81a indicating the machining contour shape path into data indicating the path for side surface finishing. 80 is a conversion means 8
The electrode moving means 3 based on the data converted by 2
Is an NC control means for controlling the movement, and notifies the electrode movement means 3 of a movement instruction in the XYZ directions.

Next, a machining procedure by the electric discharge machining apparatus in this embodiment will be described with reference to FIG. First, as a pre-stage of side surface processing using the thin pipe electrode 1, bottom surface processing, which is a primary processing, was performed. The bottom surface processing is divided into rough processing and bottom surface finishing processing, and the processing roughness can be adjusted by changing the processing conditions as described later.

Rough machining is performed by forming a layer by discharging only the bottom portion of the electrode as shown in FIG.
In FIG. 3A, 11 is a cylindrical or pipe-shaped electrode, 12 is an internal processing electrode movement path for primary processing, and 13
Is a contour side surface formed after rough machining. The electrode movement locus moves so as to cover the entire surface of the machining bottom. The rough machining was performed under the following conditions (S1).・ Electrode diameter: φ5.0mm ・ Processing current peak: 55A ・ Pulse width: 64μs ・ Dwell time: 4μs

After the rough machining, the electromachining conditions are gradually lowered as shown in FIG. 5 (b), and finally the bottom finishing is carried out by discharging only the bottom surface of the electrode under the following conditions. (S2). The bottom surface processing is completed by performing the finish processing of the bottom surface portion of the workpiece 2 in S2 (S
3).・ Processing current peak: 2.5A ・ Pulse width: 2μs ・ Pause time: 2μs

Next, the side surface processing procedure (S4 to S8) using the thin pipe electrode 1 in this embodiment will be described.
FIG. 6 is a diagram showing a state of side surface processing using the thin pipe electrode 1. FIG. 6A is a top view, and FIG. 6B is a side view. As shown in FIG. 6 (b), in the electric discharge machine in this embodiment, electric discharge machining is performed by the bottom surface portion of the thin pipe electrode 1.

In FIG. 6, reference numeral 1 denotes a thin-walled pipe electrode having a wall thickness t for side surface finishing. 2 is a side surface portion of the workpiece. Further, 13 is an unfinished portion of the side surface of the work piece 2, and 14 is a finished surface after being side processed by the thin pipe electrode 1.

The electrode moving means 3 connects the thin pipe electrode 1 to
The work piece 2 is shifted outward from the unfinished portion 13 on the side surface in the finishing direction by a thickness t or more, and is moved along the outer circumference of the side surface of the work piece 2 (S4). While moving in this manner, the bottom portion of the thin-walled pipe electrode 1 allows the unfinished portion 13 to have a constant width w.
Is processed to remove a certain depth (S6). During processing by the thin pipe electrode 1, the thin pipe electrode 1 is rotated around the cylinder axis.

In this embodiment, the X-axis direction is the direction along the side surface of the workpiece and is the downward direction in the top view of FIG. 6 (a). The Y-axis direction is a direction toward the side surface of the workpiece, and is the right direction in the side view of FIG. 6B. Z
The axial direction is the depth direction of the workpiece orthogonal to both the XY axes and is the downward direction in the side view of FIG. 6B.

The thin-walled pipe electrode 1 is moved (XY movement) along the outer periphery of the hole formed in the workpiece by the bottom surface processing.
When performing the processing, the wear of the bottom surface of the electrode progresses, so that the gap between the electrode and the object to be processed widens and the processing does not proceed. Therefore, it is necessary to perform the feed correction in the Z-axis direction according to the constant XY movement distance (S5).

However, in this case, since the side surface accuracy is not affected by the magnitude of the Z-axis feed amount, it is not necessary to calculate the Z-axis feed amount using a simulator or the like, and a preset predetermined value is set. Only the amount needs to be sent constantly according to the XY movement distance.

The feed amount in the Z-axis direction is set as follows. If the feed amount in the Z-axis direction is large, the machining contour electrode path 1
The processing depth per layer becomes large. However, since the inclination of the consumption shape of the bottom surface portion of the thin pipe electrode 1 becomes large, after the electrode path remains on the processed bottom surface of the workpiece. for that reason,
The feed amount in the Z-axis direction is gradually reduced as the machining is completed, and is finally set to approach 0.

While performing Z-axis feed in addition to XY movement as described above (S5), one round of machining is performed along the inner circumference of the hole drilled in the workpiece by bottom machining (S5).
By performing 6), side surface finishing with a constant depth is performed.
By repeating such a process, the side surface portion of the workpiece is gradually processed into a layered form from the top, and when the thin pipe electrode 1 reaches the workpiece bottom portion (S7),
The side surface finishing with the thin pipe electrode 1 is completed (S
8).

When processing the side surface, the wall thickness t of the thin pipe electrode 1
And the relationship between the thickness w of the side surface of the workpiece to be processed and removed,
It is necessary to have the following relationships. w ≧ t (1)

FIG. 7 shows the relationship between the thickness t of the thin pipe electrode 1 and the side surface shape accuracy. The side shape accuracy shown in FIG.
Amount to be removed by removing the side surface of the workpiece 2 (hereinafter,
It is described as the side surface finishing amount) w is constant, and thin-walled pipe electrode 1
The values are shown when the wall thickness t of is changed. As is clear from this figure, when w ≧ t, highly accurate machining can be performed regardless of the size of t, but when w <t, the precision of the machined shape sharply deteriorates. In the range of w ≧ t, the error in the processing accuracy that occurs depends on the vertical accuracy of the thin pipe electrode 1, and is a substantially constant value. Therefore w ≧
In the range of t, by maintaining the verticality of the thin pipe electrode 1 with high accuracy, the processing error can be approximated to 0 without limit.

The reason why the accuracy characteristic shown in FIG. 7 is obtained will be described with reference to FIG. When w <t, the positional relationship between the cylindrical electrode and the workpiece is as shown in FIG.
When electric discharge machining is performed while lowering the cylindrical electrode in the Z-axis direction, the angle E1 of the cylindrical electrode and the angle E of the workpiece 2
2 is most consumed, and the corner E1 of the cylindrical electrode and the corner E2 of the workpiece 2 are rounded. When the cylindrical electrode is further lowered in the Z-axis direction, the bottom surface of the cylindrical electrode and the workpiece 2
The gap distance between them becomes different in each part of the bottom surface portion of the cylindrical electrode, resulting in a difference in the amount of electrode consumption.

When the cylindrical electrode is further lowered in the Z-axis direction, the shapes of the cylindrical electrode and the workpiece 2 which are deformed due to electrode consumption are transferred to the workpiece 2 and the cylindrical electrode which face each other, and finally. The shape of the cylindrical electrode is an upper right slanted shape as shown in FIG. Therefore, the precision of the processed shape of the workpiece 2 deteriorates.

On the other hand, when w ≧ t, the thin-walled pipe electrode 1
The positional relationship between the workpiece and the workpiece is as shown in FIG. When the thin pipe electrode 1 is processed by lowering it in the Z-axis direction,
The corners E1 and E3 of the thin pipe electrode 1 are rounded,
The corner E2 of the work piece 2 is hardly consumed. Further, even if the thin pipe electrode 1 is lowered in the Z-axis direction, the work piece 2
The corner E2 of the thin pipe electrode 1
The shape of is consumed almost symmetrically.

Therefore, unlike the case of w <t, the consumption is symmetrical and the thin-walled pipe electrode 1 is rotated, so that almost the entire bottom surface of the thin-walled pipe electrode 1 is consumed at the same time. For this reason, the unprocessed material of the workpiece as shown in FIG. 26 does not occur, and the processed shape accuracy becomes good.

Theoretically, the relation between the thickness t of the thin pipe electrode 1 and the thickness w of the side surface of the workpiece to be processed and removed is w =
If the relationship of t is satisfied, the processing can be performed accurately. However,
It is necessary to make the wall thickness t smaller than w according to the accuracy of electrode movement by the electrode moving means 3. The reason is that the electrode may move when the electrode is moved by the electrode moving means 3, and even if such a shake occurs, the thin-walled pipe electrode 1 with respect to the workpiece 2 as shown in FIG. This is because it is necessary to maintain the positional relationship of w ≧ t as shown in b). Further, it is necessary to make the wall thickness t of the thin pipe electrode 1 smaller than the side face finishing amount w even in accordance with the shape accuracy of the inner surface of the thin pipe electrode 1, for example, the misalignment. The reason is that it is generally difficult to obtain the shape accuracy of the inner diameter of the thin pipe electrode 1 as compared with the shape accuracy of the outer diameter.

Thin-walled pipe electrode 1 in the above-mentioned side surface processing procedure
2, the NC control means 80 receives information from the conversion means 82 for enlarging or reducing the contour shape path in the lateral direction by the lateral finishing amount, and this NC
This is performed by the control means 80 controlling the electrode moving means 3.

FIG. 9 shows a state in which the side surface finishing is performed using the thin pipe electrode 1 after the bottom surface processing shown in FIG. Reference numeral 1 is a thin-walled pipe electrode, 14 is a contour side surface formed by side surface finishing, and 15 is an electrode movement path for side surface processing. The electrode moving path 15 is a path along the side surface shape. As a result, it becomes possible to maintain extremely high accuracy of side surface shape as in the case of bottom surface processing, and further to make the surface roughness of the side surface finer.

The electrode and electrical conditions for the side surface finishing performed this time are as follows.・ Electrode diameter: φ5.0mm, wall thickness 0.2mm ・ Processing current peak: 2.5A ・ Pulse width: 2μs ・ Dwell time: 2μs Copper, brass, etc. are suitable as the material of the electrode, and the thickness of the electrode The appropriate material will be selected accordingly. The amount of side surface finishing performed under these conditions was 0.3 mm.

The effect of the electric discharge machining method and apparatus using the thin pipe electrode 1 in this embodiment will be described.
Since the electric discharge machining method and apparatus using the thin-walled pipe electrode 1 in this embodiment is machining by the bottom face portion of the thin-walled pipe electrode 1, the electrode side surface is hardly consumed as shown in FIG. 26, and the entire electrode bottom face is almost flat. Wears out.

Therefore, since it is not necessary to replace the electrodes because the shape accuracy of the electrodes deteriorates due to the consumption of the electrodes, it is possible to reduce the frequency of electrode replacement as compared with the conventional case. Therefore, it is possible to perform side surface finishing while maintaining the vertical accuracy of the side surface of the work piece with extremely high accuracy, without frequently changing the electrodes.

Further, since the electrode bottom surface of the thin-walled pipe electrode 1 is consumed almost flatly, the Z-direction correction associated with the electrode consumption can be executed without performing complicated calculation processing such as simulation.

The flow of information for NC control is shown in FIG.
However, as shown in FIG. 10, it is also possible to store the contour shape path as a program having offset information and perform the processing by changing the offset.

The change of the offset means to shift from the initial shape path by an offset amount H1 in the direction perpendicular to the path as shown in FIG. For example, in the case of a clockwise shape path on a circle, if the offset direction is set to the right and the offset amount is set to 10, the path is changed to a circle whose radius increases by 10. On the other hand, if the offset direction is set to the left, the route is changed to a circle whose radius is decreased by 10.

In FIG. 10, reference numeral 81 is a storage means for storing a desired machining contour shape path 81a, a side surface finishing amount 81b, a side surface direction 81c with respect to the electrode advancing direction, and the like.
Reference numeral 0 is an NC control means. The following 80a to 80c are required as the components of the NC control means 80. Reference numeral 80a is offset program storage means, 80b is offset value storage means, and 80c is relative position control means.

The offset value stored in the offset value storage means 80b is input to the offset program storage means 80a, and the contour shape path data is converted by the offset value by the offset program stored in the offset program storage means 80a. The data converted by the offset program is input to the relative position control means 80c, and the relative position control means 80c controls X, Y, Z.
A shaft movement signal is input to the electrode moving means 3.

The NC control means 80 using such an offset program is effective because the contour shape path 80a can be converted simply by setting an offset value.

In this embodiment, the vertical side surface is finished, but the tapered side surface can be finished by the same method. FIG. 23 shows how the tapered side surfaces are finished. Specifically, basically, the thin-walled pipe electrode 1 is moved in the XYZ directions as in the case of finishing the vertical side surface, but the movement amount in the Y direction is adjusted according to the taper of the workpiece. Meanwhile, the thin pipe electrode 1 is moved. In this case, the wall thickness t of the thin-walled pipe electrode 1 needs to be equal to or less than the amount w to be removed by taper finishing (hereinafter, referred to as taper finishing amount) w.

In the present embodiment, the case in which the thin pipe electrode 1 side is moved in the XYZ directions by the electrode moving means 3 has been described, but the workpiece 2 side may be moved in the XYZ directions. Furthermore, thin-walled pipe electrode 1
Is rotated about the axis of the thin pipe electrode 1, but the workpiece 2 side may be rotated. That is, it suffices if it can move and rotate relative to the workpiece 2.
This also applies to the following embodiments.

Further, in the present embodiment, the side surface finishing processing (S4 to S8 in FIG. 4) performed after the bottom surface processing (S1 to S3 in FIG. 4) of the processing object has been described. The method described in the present embodiment can be applied to any side surface finish such as the above.

Embodiment 2 This embodiment corresponds to embodiment 1.
The present invention relates to an electric discharge machining apparatus that automatically determines the end of machining of side surface machining shown in (4) and stops machining, which will be described below with reference to FIGS. The overall view of this embodiment is the same as that of FIG. 1 and the detailed view showing the flow of information for NC control is the same as that of FIG. 2 or FIG.

In the first embodiment, when the side surface finishing is performed, it is necessary to determine whether or not the thin-walled pipe electrode 1 has reached the bottom surface of the workpiece 2 and terminate the movement of the thin-walled pipe electrode 1. This determination can be performed by recognizing the electrode moving speed that changes as the thin pipe electrode 1 reaches the bottom surface of the workpiece 2. The bottom surface of the workpiece 2 in this embodiment is the bottom surface formed on the workpiece 2 by the bottom surface processing described in the above embodiment.

In the second embodiment, an electric discharge machining apparatus will be described in which the end of machining of side surface finishing machining is determined and the movement of the thin pipe electrode 1 is automatically stopped.

First, the configuration of a circuit for determining the end of side surface processing will be described with reference to FIG. The circuit for determining the end of the side surface processing will be described as provided in the NC control unit 8 in FIG. In FIG. 11, reference numeral 80 is an NC control means for controlling the electrode moving means 3 shown in FIG. 1, and 83 is a time measuring means for measuring the moving time of the thin pipe electrode 1. The time measuring means 83 is connected to the output side of the NC control means 80, and the start and end of time measurement are performed by receiving a signal from the NC control means 80.

Reference numeral 84 is a moving distance measuring means for measuring the moving distance of the thin pipe electrode 1 by the electrode moving means 3.
The moving distance measuring means 84 is connected to the output side of the NC control means 80, receives a feedback signal at the time of the XYZ movement command from the NC control means 80, and measures the moving distance by confirming the moving position. Since the thin-walled pipe electrode 1 moves in the XYZ directions, the moving distance of the thin-walled pipe electrode 1 measured by the moving distance measuring unit 84 may be the moving distance in any of the X, Y, and Z directions.

Reference numeral 85 is an electrode moving distance storage means which is connected to the output side of the moving distance measuring means 84 and stores the moving distance measured by the moving distance measuring means 84. 86
Is an average moving speed calculating means connected to the output side of the electrode moving distance storing means 85 and the time measuring means 83. 87
Is a stationary average speed storage means for storing the stationary average speed, and is connected to the output side of the average moving speed calculation means 86.

The steady state is when the thin-walled pipe electrode 1 does not reach the processing bottom surface of the workpiece and is processing the side surface of the workpiece, and the average electrode moving speed in the steady state is After the side surface processing by the thin-walled pipe electrode 1 is started, it is obtained by measuring the average electrode moving speed at the processing stable time after one round of the electrode moving path. This value increases in accuracy by measuring multiple times and taking the average.

Reference numeral 88 is an average speed storing means connected to the output side of the average moving speed calculating means 86. The average speed stored in the average speed storage means 88 is reset every speed calculation by the average moving speed calculation means 86. The number of times of speed calculation by the average moving speed calculation means 86 depends on the required shape accuracy. Basically, it suffices to perform the calculation at least once before the thin-walled pipe electrode 1 goes around the outer circumference of the hole formed in the workpiece 2.

Numeral 89 is a speed comparing means which is connected to the output sides of the average speed storing means 87 and the average speed storing means 88 in a steady state and compares the speeds output from both the storing means 87 and 88. The speed comparison means 89 notifies the NC control means 80 of the comparison result.

Next, an operation procedure for determining the end of side surface processing will be described with reference to FIG. Time measuring means 8
In No. 3, time is measured every time the thin pipe electrode 1 moves a certain distance in any of X, Y, and Z directions during side surface processing (S11) (S12). Moving distance measuring means 84
Measures the movement distance of the thin pipe electrode 1 recognized by confirming the movement position by the feedback signal at the time of the XYZ movement command by the NC control means 80 (S13). The measured moving distance is stored in the moving distance storage means 85.

Then, the average moving speed calculating means 86 measures the moving distance from the moving distance storing means 85 and the time measuring means 8.
The average moving speed of the thin-walled pipe electrode 1 is calculated from the moving time from 3 (S14). The steady-state average electrode movement speed is stored in the steady-state average speed storage means 87, which is a referenceable storage means.

The speed comparing means 89 is an average speed storing means 8
It is determined whether or not the average moving speed stored in 8 is abruptly slower than the average moving speed stored in the average speed storing means 87 in the steady state (S16).

The speed comparison means 89 sends the comparison result to the NC control means 80, and the NC control means 80 stops or continues the movement of the thin-walled pipe electrode 1 based on the comparison result of the speed comparison means 89.

Specifically, when the average moving speed stored in the average speed storing means 88 is sharply slower than in the steady state, the thin-walled pipe electrode 1 reaches the bottom surface of the workpiece 2. Upon recognizing that it has arrived (S17), the movement of the thin pipe electrode 1 is stopped (S18). On the contrary, when the average speed stored in the average speed storage means 88 does not change compared to the steady state, it is recognized that the thin pipe electrode 1 has not reached the bottom surface of the workpiece 2. Then, the movement of the thin pipe electrode 1 is continued (S11). And S
11 to S16 are executed again.

As described above, the completion of the side surface processing can be recognized by the moving speed of the electrode for the following reason. At the time of side surface processing, the thin pipe electrode 1 is processed only by a small area overlapping the side surface portion of the workpiece 2 as shown in FIG. On the other hand, when the thin pipe electrode 1 reaches the bottom surface of the workpiece 2, the entire bottom surface of the thin pipe electrode 1 is processed 2
Since it faces the bottom surface of the electrode, the discharge is performed on the entire bottom surface of the electrode. As a result, the processing area of the thin pipe electrode 1 becomes larger when the bottom surface of the workpiece 2 is reached than when processing the side surface, so that the moving speed of the thin pipe electrode 1 inevitably becomes slower.

Therefore, by comparing the average moving speeds of the electrodes, it is possible to recognize that the electrodes have reached the bottom surface of the processing and finish the processing at an appropriate time.

The effects of the electric discharge machining apparatus according to the second embodiment will be described. In the electric discharge machining device according to this embodiment, it is possible to automatically determine the machining end of the side surface finishing machining and stop the movement of the thin pipe electrode 1. Therefore, the side surface finishing of the workpiece by the thin pipe electrode 1 can be completed accurately.

In this embodiment, the case of recognizing whether or not the bottom surface of the workpiece 2 has been reached by paying attention to the change in the electrode moving speed has been described.
In the case of finishing the peripheral side surface of the, the completion of the side surface finishing can be recognized as follows.

In the case of finishing the peripheral side surface of the workpiece 2, when the side surface finishing is completed, the bottom surface portion of the thin pipe electrode 1 does not face the side surface of the workpiece 2. Therefore, contrary to the above case, the moving speed of the thin pipe electrode 1 is necessarily increased. Therefore, in this case, when it is determined by the comparison by the speed comparing unit 89 that the moving speed has increased, the side surface finishing is completed.

Embodiment 3 This embodiment relates to an electric discharge machining apparatus for side surface machining using a disc-shaped electrode 31 having a specific thickness, which will be described below with reference to FIGS. 13 to 21. FIG. 13 is an overall view of the electric discharge machine in this embodiment. In FIG. 13, reference numeral 31 is a disk-shaped electrode used for performing side surface finishing of the workpiece 2. Since 2 to 8 are the same as those shown in the first embodiment, description thereof will be omitted.

FIG. 14 is a detailed diagram showing the flow of information in the NC control unit 8 shown in FIG. In FIG.
Reference numeral 81 indicates a machining contour shape path 81a, a side surface direction 81c with respect to the electrode traveling direction, and a constant traveling distance (XY
It is a storage unit for storing the side surface expansion amount 81b per plane).

The NC control means 80 is composed of the following means. Reference numeral 80a is an offset program storage means, 80d is an offset value storage means, 80e is a calculation means for the electrode movement distance on the XY plane, and 80c is a relative position control means.

In the NC control means 80, the offset changing means 80d changes the offset value in accordance with the electrode moving distance calculated by the electrode moving distance calculating means 80e on the XY plane. Then, the offset program converts the contour path data 81a by the changed offset value.

In this embodiment, the contour shape path 81
Since a is the path of the center of the disk-shaped electrode 31, the offset value in this embodiment corresponds to the side surface finishing amount of the workpiece.

Next, the procedure of side surface processing using the disk-shaped electrode 31 will be described with reference to FIGS. As a pre-stage of the side surface processing using the disc-shaped electrode 31, bottom processing, which is the primary processing, was performed. Since the bottom surface processing is the same as that described in the first embodiment, the details will be omitted.

After the bottom surface processing is completed, the disk-shaped electrode 31
Was used to perform side surface finishing. FIG. 16 is a diagram showing a state where the side surface finishing is performed using the disc-shaped electrode 31. In FIG. 16A, reference numeral 31 is a disk-shaped electrode used for finishing the side surface of the workpiece 2. 13
Is an unfinished portion on the side surface of the workpiece 2, and 32 is an expected finished surface to be processed by the disc-shaped electrode 31. Reference numeral 33 is a temporary finished surface processed by the disc-shaped electrode 31, and 34 is an electrode movement locus in the Z-axis direction.

In the side surface finishing using the disk-shaped electrode 31, basically, the side surface end portion of the disk-shaped electrode 31
The side surface of the workpiece 2 is processed by tracing the side surface thereof, and the disk-shaped electrode 31 is repeatedly moved up and down like a locus 34 to perform side surface finishing.

An actual processing example will be shown below. The electrodes and electrical conditions during processing are as follows. -A disk with an electrode diameter of 5.0 mm and a thickness of 2 mm-Processing current peak: 1) 55A, 2) 10A, 3) 2.
5A ・ Pulse width: 2μs ・ Pause time: 2μs

Copper, brass or the like is suitable as the electrode material, but an appropriate material is selected according to the thickness of the electrode. When copper is used as the electrode material, the thickness of the electrode can be up to about 0.3 mm. The machining current peaks 1) to 3) indicate that the machining current peak condition can be adjusted in three stages. This processing current peak condition is set to be gradually lower depending on the progress of processing.

The electrode moving means 3 moves the disk-shaped electrode 31 to the side surface of the disk-shaped electrode 31 as shown by the arrow in the X direction in the top view of FIG. And is moved toward the side surface of the workpiece 2 as indicated by an arrow in the Y direction orthogonal to the X axis. Moving the disk-shaped electrode 31 in the Y direction, which approaches the side surface of the workpiece, is generally called enlargement, and moving it away from the workpiece is generally called shrinking.

The Y direction shown in FIG. 16A shows the normal direction of the side surface of the workpiece 2. Therefore, processing the disk-shaped electrode 31 while moving it in the Y direction means that
The electrodes are expanded in the lateral direction at a constant rate according to the amount of electrode movement of the disc-shaped electrode 31 in the X direction. Further, at that time, as shown in the side view b of FIG. 16A, the electrode is lowered in the Z-axis direction orthogonal to both the XY axes at every constant movement distance of the XY plane.

The amount of drop in the Z-axis direction must be set according to the thickness of the disc-shaped electrode 31. Specifically, for example, when the thickness of the disc-shaped electrode 31 is 2 mm, the disc-shaped electrode 31 is lowered in the Z direction by the time the disc-shaped electrode 31 makes one round on the side surface of the workpiece to be machined. The amount to be set is set to be less than 2 mm.

The above setting is made if the disk-shaped electrode 31 is lowered by the thickness of the disk-shaped electrode 31 or more by the time of making one turn on the side surface of the workpiece, in the case of the processing in this embodiment. This is because the side surface of the workpiece will be processed so as to dig a spiral groove, and the entire side surface of the workpiece cannot be finished.

By moving the disc-shaped electrode 31 along the side surface formed by the bottom surface processing as shown in FIG. 5, the disc-shaped electrode 31 is lowered to the set depth. In this way, the disk-shaped electrode 31 is rotated along the side surface of the workpiece 2 until the bottom surface of the disk-shaped electrode 31 reaches the bottom surface portion of the workpiece 2. During such movement, electric discharge machining is performed by the circumferential side surface portion of the disc-shaped electrode 31.

In order to accurately reach the bottom surface of the workpiece 2 by the disc-shaped electrode 31, the machining depth can be measured in advance. Therefore, the number of revolutions and the electrode feed amount in the Z-axis direction are set accordingly. By doing so, it can be easily realized.

FIG. 17 shows the movement path of the above-mentioned disc-shaped electrode 31 from above. The NC control means 8 naturally stores in advance the traveling direction of the disk-shaped electrode 31 and the orientation of the processed side surface with respect to that direction.

As shown in FIG. 17, the disk-shaped electrode 31 is gradually moved so that its side surface is enlarged, and further the disk-shaped electrode 31 is lowered in the Z-axis direction at a constant feed rate (FIG. 1).
5), the disk-shaped electrode 31 reaches the bottom surface of the workpiece 2 (S22 in FIG. 15).

The ratio of the amount of expansion of the electrodes in the Y direction is always constant until the bottom surface of the workpiece 2 is reached. Also,
Since the expansion amount of the electrode in the Y direction is forcibly expanded to some extent, the side surface shape of FIG. 17 after the bottom surface processing inevitably has a tendency as shown in FIG. 18B. That is, the amount of processing in the side surface direction of the workpiece 2 increases as it approaches the bottom surface of the workpiece 2. This tendency is irrespective of the expansion amount in the Y direction regardless of whether it is larger or smaller than the expansion amount in the Y direction.

Next, after the disk-shaped electrode 31 reaches the bottom surface of the workpiece 2, the enlargement amount in the Y direction is S2 in FIG.
It is set smaller than the enlargement amount in 1 (S in FIG. 15).
23). The disk-shaped electrode 3 is then moved by the electrode moving means 3.
1 is moved as if following the movement path of S21 in FIG. 15 to perform side surface processing (S2 in FIG. 15).
4). Finally, the disk-shaped electrode 31 is moved to the processing start point above the Z axis (S in FIG. 15).
25). The movement of S21 in FIG. 15 is referred to as a going process, and the movement of S24 in FIG. 15 is referred to as a returning process.

However, also in the returning process, the disk-shaped electrode 31 is moved while being enlarged in the side direction according to the amount of movement in the X direction. The expansion amount is reduced compared to the expansion amount in the going process (S24 in FIG. 15). Disc-shaped electrode 3 after the return process
By returning 1 to the initial position, the side surface shape of the workpiece 2 tends to be as shown in FIG.

Since the disc-shaped electrode 31 is a thin disc,
Although the amount of electrode wear on the side surface is very large, the shape of wear on the side surface of the disk-shaped electrode is as shown in FIG. 20 when the above-described return process is performed. FIG.
20A shows the electrode consumption shape of the disc-shaped electrode 31 in the going process, and FIG. 20B shows the electrode consumption shape of the disc-shaped electrode 31 in the returning process. FIG.
(C) is a disk-shaped electrode 31 after the process of going and returning.
It is the electrode consumption shape of. In FIG. 20, 13 is an unfinished surface of the workpiece, 32 is an expected surface processed by the disc-shaped electrode, and 33 is a temporary surface processed by the disc-shaped electrode.

In the process of gradually lowering the electrode in the Z-axis direction, the disk-shaped electrode 31 is consumed at the lower part of the disk side surface as shown in FIG. 20 (a). In addition, the temporary finished surface 33
Does not perform accurate electrode wear correction and simply enlarges it, so the verticality is not very good (see the side surface of the workpiece in FIG. 18).

Next, in the return process in which the electrode is gradually raised in the Z-axis direction, the disk-shaped electrode 31 is consumed at the upper side surface of the disk as shown in FIG. 20 (b). By repeating the process of going and returning a plurality of times, the disc-shaped electrode 31 converges as shown in FIG. 20C in the final shape of the disc-shaped electrode 31. Therefore, the side surface processing of the workpiece 2 is ultimately
It is processed by the disk-shaped electrode 31 having a stable side surface shape.

In repeating the process of going and returning, if the machining was carried out while keeping the amount of expansion of the electrode in the lateral direction set at the beginning of the machining, as can be seen from FIGS. It is not possible to perform machining with good side surface machining accuracy. Therefore, it is necessary to gradually reduce the electrode expansion amount in the side surface direction Y of the workpiece 2 for each process of moving the disk-shaped electrode 31 from the top to the bottom or from the bottom to the top in the Z-axis direction (FIG. 16). (See the electrode movement locus 34 in the Z-axis direction).

By repeating the process of going and returning, the amount of electrode enlargement is gradually reduced to obtain the result shown in FIG.
As shown in (c), the side surface of the work piece 2 is flattened by the disc-shaped electrode 31, and the final vertical accuracy of the side surface of the work piece 2 can be greatly improved.

In addition, the current peak value of the electrical condition is gradually changed from 1) to 3) according to the process of going back and forth. As a result, it becomes possible to perform multi-step condition machining of side surface machining, the surface roughness of the final machined surface can be made fine, and the machining speed can be improved.

The relationship between the thickness of the disc-shaped electrode and the corner shape formed between the side surface and the bottom surface of the workpiece 2 after the side surface finishing is completed by repeating the above-described return process. Is shown as in FIG. As can be seen from FIG. 21, when the corner radius formed at the edge between the bottom surface and the side surface of the workpiece 2 is r and the thickness of the disk electrode is t, the relationship of 2r ≧ t is satisfied. Therefore, depending on the value of the allowable corner radius r which is the required accuracy, 2
It is necessary to use the disc-shaped electrode 31 having a thickness such that r ≧ t.

In other words, by using the disk-shaped electrode 31 having a thickness such that 2r ≧ t according to the value of the allowable corner radius r, which is the required accuracy, the bottom surface and the side surface of the workpiece 2 are separated. The formed edge can be suppressed to the required accuracy or less.

The effect of the electric discharge machine using the disc-shaped electrode in this embodiment will be described. In the electric discharge machining apparatus using the disc-shaped electrode in this embodiment, the disc-shaped electrode 31 is rotated to perform the side surface machining using the entire side surface of the electrode. Can be reduced. Therefore, it is possible to perform highly accurate side surface machining without frequently changing the electrodes.

Further, since the electrical conditions can be adjusted in multiple stages, it is possible to shorten the time required for side surface processing while improving the finishing accuracy. Further, since the thickness t of the disc electrode is set to satisfy the relation of 2r ≧ t, the corner between the bottom surface and the side surface of the workpiece 2 can be suppressed to be equal to or less than the allowable value.

Although the finishing of the vertical side surface is shown in this embodiment, the finishing of the tapered side surface can also be carried out by a similar method. In addition, although the electric discharge machining apparatus that automatically determines the end of machining of the side surface machining and stops machining in the second embodiment is applicable to the third embodiment using the disc-shaped electrode 31.

At the time of side surface processing, the disk-shaped electrode 31 is processed only by a small area of the disk side surface portion. When the disk-shaped electrode 31 reaches the bottom surface of the work piece 2, the entire bottom surface of the disk-shaped electrode 31 comes into contact with the bottom surface of the work piece 2, and the processing area of the electrode increases. Inevitably, the moving speed of the electrode also changes.
Therefore, by comparing the moving speeds of the electrodes as shown in the second embodiment, it is possible to determine that the disk-shaped electrode 31 is the workpiece 2
It is possible to recognize that it has reached the bottom part of the and finish the processing at an appropriate time.

Embodiment 4. This embodiment relates to an electric discharge machining apparatus for taper finishing a workpiece by using a thin pipe electrode and will be described with reference to FIGS. The overall view of the electric discharge machine in this embodiment is shown in FIG.
The description is omitted because it is similar to that shown in FIG. However, the electric discharge machining apparatus according to the present embodiment is different in that the electrode moving means 3 can move and rotate the thin-walled pipe electrode 1 in the XYZ directions, and can also tilt the thin-walled pipe electrode 1.

The NC control unit 8 can also set information on the angle at which the thin-walled pipe electrode 1 is tilted, and the thin-walled pipe electrode 1 can be moved by the electrode moving means 3 in response to a command from the NC control unit 8. Will be tilted. In the present embodiment, the angle θ at which the thin pipe electrode 1 is tilted
Will be described as an angle formed by the central axis of the thin pipe electrode 1 and the vertical direction.

FIG. 24 is a diagram showing the flow of information in the NC control unit 8 in this embodiment. In FIG.
The storage means 81 stores the contour shape path 81a and the side surface finishing amount 81.
The information of b, the side face direction 81c with respect to the electrode moving direction, and the angle 81e for inclining the electrode is stored. NC control means 8
Based on the information stored in the storage unit 81, 0 notifies the electrode moving unit 3 of a movement instruction in the XYZ directions, and also notifies the electrode moving unit 3 of an instruction of the angle θ for tilting the electrode. .

Next, a taper finishing method using the thin pipe electrode 1 will be described with reference to FIG. In FIG. 25, the relationship between the wall thickness t of the thin pipe electrode 1 and the width w to be removed by taper finishing is t ≦ w. FIG. 25
As can be seen from (a), the thin pipe electrode 1 is inclined by an angle θ so that the side surface of the electrode is in contact with the tapered side surface of the workpiece 2.

A method of moving the thin pipe electrode 1 at the time of taper finishing will be described. First, the thin pipe electrode 1 is shown in FIG.
It moves in the X direction in (b). In this embodiment, the X direction means the workpiece 2 as shown in FIG.
The direction along the taper side surface of. Then, the thin-walled pipe electrode 1 is processed while moving so as to circulate around the tapered side surface of the workpiece 2.

The thin pipe electrode 1 is fed in the direction of the central axis of the thin pipe electrode 1 as the thin pipe electrode 1 moves in the X direction. Therefore, the feeding is not in the Z direction, but in the YZ direction inclined by an angle θ from the vertical direction. That is, the thin pipe electrode 1 is inclined by the angle θ on the YZ plane. In this embodiment, the Y direction means a direction toward the workpiece 2.

When the thin-walled pipe electrode 1 moves so as to circulate around the tapered side surface of the workpiece 2, the thin-walled pipe electrode 1
It is necessary to switch the tilt direction of. However, even in this case, the inclination angle θ is maintained.

At the time of electric discharge machining, the thin-walled pipe electrode 1 is rotated around the axis, and the bottom surface of the thin-walled pipe electrode 1 is used for electric discharge machining. By moving the thin pipe electrode 1 in this manner, taper finishing can be performed.

The effect of taper finishing using the thin pipe 1 in this embodiment will be described. By performing the taper finishing process while moving the thin-walled pipe electrode 1 as shown in this embodiment, it is possible to perform more accurate finishing process than the taper finishing process shown in the first embodiment. The reason for this is that the processing is performed while inclining the side surface of the thin-walled pipe electrode 1 along the tapered surface, so that the bottom surface of the thin-walled pipe electrode 1 is consumed almost flatly. Further, the surface roughness can be removed by the secondary discharge that occurs between the side surface of the thin pipe electrode 1 and the processed tapered surface, and a clean finished surface is obtained.

[0121]

EFFECTS OF THE INVENTION A cylindrical machining electrode having a wall thickness equal to or less than the side surface finishing amount of a workpiece is moved relative to the workpiece, and the axis of the cylinder is moved relative to the workpiece. By rotating relatively to the center and performing the side surface finishing processing for the side surface finishing amount of the work piece by the cylinder bottom surface portion of the working electrode, the work piece electrode is not frequently replaced, Highly accurate side surface finishing is possible.

The disk-shaped electrode is rotated relative to the work piece relative to the axis center of the disk, and is relatively moved in the X-axis direction along the side surface of the work piece, orthogonal to the X-axis. The disk-shaped electrode is relatively enlarged in the Y-axis direction toward the side surface of the workpiece, and relatively moved in the Z-axis direction orthogonal to both the X-axis and the Y-axis according to the thickness of the disk-shaped electrode. Since the side surface of the workpiece is machined by the circumferential side surface, the side surface of the workpiece can be finished with high accuracy without frequently replacing the machining electrode.

Since the thickness of the disc-shaped electrode is set to not more than twice the desired corner radius of the corner formed between the side surface of the workpiece and the bottom surface of the workpiece in contact with the side surface. The corner radius formed between the side surface of the workpiece and the bottom surface of the workpiece in contact with the side surface can be suppressed to the required accuracy or less.

A cylindrical machining electrode having a wall thickness equal to or less than the taper finishing amount of the workpiece is moved relative to the workpiece, and the axial center of the cylinder is moved relative to the workpiece. While relatively rotating, while tilting the machining electrode in a direction in which the cylindrical side surface of the machining electrode is in contact with the tapered side surface of the workpiece, the cylindrical bottom surface of the machining electrode causes the taper finish of the workpiece. Since the amount of taper finishing is performed, the work piece can be tapered with high accuracy without frequently changing the working electrode.

Moving speed measuring means for measuring the moving speed of the processing electrode, moving speed comparing means for comparing the moving speed measured by the moving speed measuring means with a reference value,
Based on the comparison result by the moving speed comparison means, it has a determination means for determining whether or not to finish the side surface processing of the workpiece by the processing electrode, so that the side surface processing by the processing electrode is accurately finished. Can be made.

[Brief description of the drawings]

FIG. 1 is an overall view of an electric discharge machine according to a first embodiment.

FIG. 2 is a diagram showing a flow of information up to an NC control unit 8.

FIG. 3 is a diagram showing an electrode path in bottom surface processing.

FIG. 4 is a diagram showing a procedure of side surface finishing using the thin pipe electrode 1 in the first embodiment.

FIG. 5 is a diagram showing how bottom surface processing is performed.

FIG. 6 is a diagram showing a state of side surface processing by the thin pipe electrode 1.

FIG. 7 is a graph showing the relationship between the wall thickness t of the thin pipe electrode 1 and the side surface shape accuracy.

FIG. 8 is a diagram showing the positional relationship with respect to the workpiece when the wall thickness t of the thin pipe electrode 1 is made larger and smaller than the side surface finishing amount.

FIG. 9 is a view showing an electrode path in the side surface processing by the thin pipe electrode 1.

FIG. 10 is a diagram showing another example of the flow of information up to the NC control means 8.

FIG. 11 is a block diagram showing a circuit for automatically determining the end of side surface processing.

FIG. 12 is a diagram showing a procedure for automatically determining the end of side surface processing.

FIG. 13 is an overall view of an electric discharge machine according to a third embodiment.

FIG. 14 is a diagram showing the flow of information up to the NC control means in the third embodiment.

FIG. 15 is a diagram showing a procedure of side surface finishing with the disc-shaped electrode 31.

FIG. 16 is a diagram showing a state of side surface finishing with the disc-shaped electrode 31.

FIG. 17 is a top view showing a movement path of the disc-shaped electrode 31.

FIG. 18 is a view showing the shape of the workpiece 2 after the going process.

FIG. 19 is a view showing the shape of the workpiece 2 after the returning process.

FIG. 20 is a diagram showing an electrode consumption shape of the disk-shaped electrode 31.

FIG. 21 is a diagram showing the relationship between the thinness of the disk-shaped electrode 31 and the allowable corner radius.

FIG. 22 is a diagram showing a path after offset conversion of a contour shape path.

FIG. 23 is a diagram showing how taper finishing is performed by the thin pipe electrode 1.

FIG. 24 is a diagram showing a flow of information up to NC control according to the fourth embodiment.

FIG. 25 is a diagram showing how taper finishing is performed by the thin pipe electrode 1 according to the fourth embodiment.

FIG. 26 is a diagram showing a state of machining by a conventional electric discharge machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 thin-walled pipe electrode, 2 workpiece, 3 electrode moving means, 4 working liquid, 5 working tank, 6 working liquid supply means, 7
Processing power source, 8 NC control unit, 31 disc-shaped electrode,
80 NC control means, 83 time measuring means, 84 electrode moving distance measuring means, 85 electrode moving distance storing means, 86
Average moving speed calculating means, 87 Average speed storing means during side surface processing, 88 Average speed storing means, 89 Speed comparing means.

Claims (7)

[Claims] 1. A cylindrical machining electrode having a wall thickness equal to or less than a side surface finishing amount of a workpiece, a power source for applying a voltage between the machining electrode and the workpiece, and the workpiece. Rotating means for rotating the machining electrode relative to the workpiece about the axis of the cylinder; moving means for relatively moving the machining electrode with respect to the workpiece; An electric discharge machining apparatus comprising: a control means for controlling relative movement of electrodes; and a side surface finishing machining of a side surface finishing amount of the workpiece by a cylindrical bottom surface portion of the machining electrode. 2. A disk-shaped machining electrode, a power supply for applying a voltage between the machining electrode and the workpiece, and the machining electrode for the workpiece. Rotating means for relatively rotating about the axis, and relative movement in the X-axis direction along the side surface of the workpiece with respect to the workpiece, relative to the workpiece, the workpiece side surface orthogonal to the X axis. Relatively enlarged movement in the Y-axis direction
It has a moving means for relatively moving in the Z-axis direction orthogonal to both the X and Y axes according to the thickness of the disc-shaped electrode, and a control means for controlling the relative movement of the machining electrode by the moving means. An electric discharge machining apparatus is characterized in that the side surface of the workpiece is machined by the side surface of the circumference of the machining electrode. 3. The thickness of the disk-shaped electrode is not more than twice the desired corner radius dimension of a corner formed between the side surface of the workpiece and the bottom surface of the workpiece in contact with the side surface. The electric discharge machine according to claim 2, wherein 4. A cylindrical machining electrode having a wall thickness equal to or less than the taper finishing amount of the workpiece, a power source for applying a voltage between the machining electrode and the workpiece, and the workpiece. Rotating means for relatively rotating the machining electrode with respect to the workpiece about the axis of the cylinder; moving means for relatively moving the machining electrode with respect to the workpiece; and tapered side surfaces of the workpiece. The tilting means for tilting the working electrode in the direction in which the cylindrical side surface of the working electrode is in contact with, and the control for controlling the relative movement of the working electrode by the moving means and the tilt of the working electrode by the tilting means. And a means for performing taper finishing by an amount corresponding to a taper finishing amount of the workpiece by the bottom surface portion of the machining electrode. 5. A moving speed measuring means for measuring a moving speed of the processing electrode, a moving speed comparing means for comparing the moving speed measured by the moving speed measuring means with a reference value, and the moving speed comparing means. 5. The electric discharge machining according to claim 1, further comprising: a discriminating unit for discriminating whether or not the side surface machining of the workpiece by the machining electrode is to be terminated based on the comparison result. apparatus. 6. A cylindrical machining electrode having a wall thickness equal to or less than the side surface finishing amount of the workpiece is moved relative to the workpiece, and the axis of the cylinder is relative to the workpiece. A method of electrical discharge machining, which is characterized by rotating relatively to the center, and performing side surface finishing by an amount corresponding to the side surface finishing amount of the workpiece by the bottom surface of the cylinder of the machining electrode. 7. A disk-shaped electrode is rotated relative to a workpiece relative to an axis of the disk, and is relatively moved in an X-axis direction along a side surface of the workpiece, orthogonal to the X-axis. And relatively moves in the Y-axis direction closer to the side surface of the workpiece, and relatively moves in the first direction of the Z-axis orthogonal to both the X-axis and the Y-axis depending on the thickness of the disc-shaped electrode. A first processing step of performing side surface processing of the workpiece by a circumferential side surface portion of the disk-shaped electrode; and, after the first processing step, the disk-shaped electrode for the workpiece, The disk is rotated relative to the axis of the disk and relatively moved in the X-axis direction, and relatively expanded in the Y-axis direction by an expansion amount smaller than the expansion amount in the first processing step. Depending on the thickness of the plate-shaped electrode, move it relative to the second direction of the Z-axis, and Discharge machining method characterized by a second processing step of performing a side milling of the workpiece by the circumferential side surface portion of the disc-shaped electrode.