JPH0547334B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to close machining in a uniaxial direction (main machining axis direction, usually Z-axis direction) in which a workpiece and a machining electrode are opposed to each other. Machining by relatively applying a feed, or after machining by the machining feed, relatively applying a translational movement of a predetermined amplitude in a plane substantially perpendicular to the one axis between the electrode and the workpiece. This invention relates to an electrical discharge machining method.

[Conventional technology]

Generally, in order to improve the efficiency of electrical discharge machining, it is necessary to effectively eliminate chips generated in the electrical discharge machining gap between the workpiece and the machining electrode and increase the effective discharge rate in the electrical discharge machining gap. It is well known that it is good.

When finishing electrical discharge machining, one of the machining methods that meets the above-mentioned purpose is to apply a required translational movement between the workpiece and the machining electrode in a plane direction that is approximately perpendicular to the opposing uniaxial direction. A machining method is known in which the electric discharge machining gap is sequentially moved along a machining shape that is substantially similar to the contour shape of the cross section of the electrode, thereby helping to remove chips. In addition, Japanese Patent Application Laid-open No. 107840/1983 describes that when performing a translational motion that reciprocates radially along an X-Y plane perpendicular to the uniaxial direction of the main machining for finishing machining, this X- A method has been proposed in which an auxiliary displacement movement such as a minute eccentric circular motion is superimposed on a translational movement of a minute displacement in the Y plane, thereby improving machining efficiency. Furthermore, other known methods include applying a jet to the discharge machining gap to forcibly remove chips, or applying a jump motion to the machining electrode and using the resulting pumping effect to remove chips. .

[Problem to be solved by the invention]

According to the above-mentioned machining method that provides relative translational motion between the machining electrode and the workpiece, it is possible to expect chips to be removed without interrupting machining, but such translational motion is usually Since it is carried out at a moderate speed, the ability to remove chips is small, although it depends on the shape of the machined.

In other words, in conventional machining using translational movement for close machining, newly machined chips are generated in the machining gap between the electrode side surface and the machining hole side surface, and the machining chips that are newly created in the machining gap between the electrode side surface and the machining hole side surface are processed sequentially by relatively slow translational motion. This causes the material to be caught in the gap, which not only requires feed control operations such as stopping, retracting, and advancing for translational movement, but also machining using translational movement such as near-end machining is usually performed on a single axis (Z-axis). After main machining in the direction, or after the main machining has been carried out to a certain extent, it is used in combination with the main machining, and is performed as a movement within the hole machined by the main machining and within a plane substantially perpendicular to the uniaxial direction. Therefore, the ejection of processed chips from the processed hole is not carried out much by the above-mentioned translational movement, as it only stirs the inside of the processed hole, and as the processing progresses, the processed chips concentration in the processed hole increases. Eventually, the machining operation becomes unstable and the machining efficiency decreases. It was necessary to use them in combination.

In addition, the method disclosed in the above-mentioned Japanese Patent Application Laid-open No. 107840/1984 uses a translational movement that reciprocates radially along the X-Y plane, and a minute eccentric circular movement within the same plane. Since it superimposes the auxiliary displacement motion of However, the pumping effect for removing chips cannot be expected.

On the other hand, in the method of removing chips using a jet,
In addition to requiring special equipment to control jet flow timing and period, etc., it is also necessary to form grooves, holes, etc. in the processing electrode, and to provide separate nozzles, etc., which tends to increase costs. have.

In addition, the method of jumping the machining electrode has a high chip removal ability, but not only does it have the problem of interrupting machining during the jump, but it also has various problems such as the timing of the jump operation and the stroke. In addition to setting the conditions, there was a problem that complicated settings and controls were required, such as controlling the retreat path of the processing electrode from the translational movement processing position and the path and speed for returning to the processing position. .

Therefore, the present invention relates to an improvement in a method of machining a workpiece and a machining electrode while applying machining translational motion to the workpiece and a machining electrode in a plane direction substantially perpendicular to the opposing uniaxial direction during finishing machining of electrical discharge machining. Another object of the present invention is to provide an electric discharge machining method that uses the above-mentioned translational motion, which can effectively remove machining chips without interrupting electric discharge machining, and can significantly improve electric discharge machining efficiency.

[Means to solve the problem]

The characteristics of the method of the present invention for achieving the above object are as follows: relatively providing a uniaxial proximity machining feed facing each other between the workpiece and the machining electrode;
Or in an electric discharge machining method in which, after machining by the machining feed, a translational movement of a predetermined amplitude is relatively applied between the electrode and the workpiece in a plane substantially perpendicular to the one axis, The above translational movement is performed by displacing the electrode relative to the workpiece by a predetermined minute distance in a direction perpendicular to the uniaxial direction, so that the side surface of the electrode and the side surface of the machining hole of the workpiece are closely opposed to each other. In addition to the relative motion sequentially along the contour shape of the electrode cross section perpendicular to the one axis, which is given as a state of rotation, the motion in a plane substantially perpendicular to the direction of the axis of motion along the contour shape It is characterized in that it superimposes auxiliary motion consisting of relative rotational motion with a minute displacement width around the axis.

Further, the present invention is characterized in that the auxiliary movement consisting of the rotational movement is superimposed on the movement along the contour shape intermittently at predetermined intervals.

[Effect]

The rotational movement with a small displacement width superimposed on the translational movement for finishing of the present invention is a rotational movement with a small displacement width in a plane substantially perpendicular to the axis in the direction of the translational movement and around the axis in the direction of the translational movement. Although the stroke is small,
It has a motion component in the uniaxial direction, and not only simply stirs the machining fluid in the machining hole, but also has a pumping action to supply and discharge the machining fluid to the machining hole, and has a machining chip discharge function, It has become possible to perform continuous machining using stable translational motion, and there are also various ways of stirring the machining fluid and changing the machining gap. Especially, the microscopic The displacement movement is preferable because it variously changes and stirs the machining gap formed by advancing.

〔Example〕

Hereinafter, the electric discharge machining method of the present invention will be explained in detail with reference to the illustrated concrete machining example.

FIG. 1 shows how a full-form machining electrode 1 is used to make a hole or engrave a hole in a workpiece 2. As shown in FIG. The machining electrode 1 is fixed to a machining head (not shown), while the workpiece 2 is attached to a machining table (not shown) and are arranged facing each other in a uniaxial direction. The machining electrode 1 can be moved in the Z-axis direction by the machining head, while the workpiece 2 can be moved by the machining table in the X-Y plane perpendicular to the Z-axis. Can be moved.

The illustrated embodiment uses a machining electrode 1 to form a machining hole 3 through or with a predetermined depth in a workpiece 2 by uniaxial (Z-axis) feeding in electrical discharge rough machining, semi-finishing machining, etc. This is an example of machining when so-called finishing machining is performed by the machining method of the present invention.

In FIG. 1, after the Z-axis feed machining is completed, the electrical machining conditions are switched to the final or desired finishing machining conditions, and the electrode 1 is moved to the workpiece 2 perpendicular to the Z-axis direction. By relatively displacing the holes by predetermined distances in the X and Y axis directions, that is, in the case shown in the figure, a machining gap of a predetermined distance l is formed with the side surface of the upper machining hole where machining is to be started. along with displacement in the Y-axis direction,
In the case shown in the figure, a slightly smaller displacement is applied in the X-axis direction than in the Y-axis direction, and the components are arranged in the illustrated positional relationship.
O is a point on the cross section of the processing electrode 1 taken along the XY plane perpendicular to the Z axis, and arrows a, b, c,
As shown by the locus d, by sequentially applying minute displacements of the length of each arrow line similar to the outer circumferential contour shape of the electrode cross section, a translational movement for bringing the machining electrode 1 and the workpiece 2 together is created. is given, and the finishing process of the inner peripheral wall surface of the processing hole 3 is performed using the processing electrode 1.

Therefore, the lengths of the arrows a, b, c, and d are such that after the machining is completed by the translational movement of each arrow length, the distance between the side surface of the hole to be machined next and the 1 of the machining gap, and the present invention combines the translational motion of the above-mentioned nearing machining with a rotational motion of a minute displacement width around each motion axis in a plane perpendicular to each motion axis. This is to perform the nearing process while applying superimposition as an auxiliary movement.

As shown in FIG. 2, the auxiliary motion superimposed on this translational motion is an arrow a, It is performed as a rotational movement around the movement axis in each plane perpendicular to the axial direction of the translational movements b, c, and d. In the case shown in the figure, the processing electrode 1 is The motion is a circular motion with a predetermined radius r around each axis of motion parallel to and d. As a result, the processing electrode 1
The reciprocating motion of approaching and separating the workpiece 2 also occurs in a direction perpendicular to the processing plane. The radius r of this circular motion is set to a predetermined value smaller than the distance l between the two (see Figure 1) when the processing electrode 1 approaches the inner surface of the processing hole 3 due to the above-mentioned translational movement. ing. Therefore, even if the auxiliary movement is superimposed on the translational movement, the processing electrode 1 will not come into contact with the workpiece 2. In order to suppress the influence of the change in the electric discharge machining gap length due to the superimposition of the auxiliary motion on the electric discharge state of the gap as small as possible, it is preferable to suppress the value of r to about half of the distance l.

Furthermore, as described above, when the auxiliary movement in the plane perpendicular to the axis of the above-mentioned translational movement is superimposed on the translational movement for near-machining between the processing electrode 1 and the workpiece 2, the resulting The relative movement between them becomes a spiral movement as shown in FIG. The pitch of this spiral is determined by the cycle of the circular motion, which is the auxiliary motion, and the machining feed rate of the translational motion, and can be appropriately determined based on the state of the machining gap. In this case, the circular motion as the superimposed auxiliary motion may be performed continuously or may be performed intermittently at predetermined time intervals.

FIG. 3 shows the movement trajectory of the processing electrode 1 relative to the workpiece 2 when circular movement around the movement axis is intermittently performed in a plane perpendicular to the axis of translational movement as auxiliary movement. An example is shown.

In this way, a circular motion in a plane perpendicular to the axis of translational motion is added to the translational motion that is performed relatively between the machining electrode 1 and the workpiece 2 along the contour line shape of the electrode cross section. Or, when the auxiliary motion of the rotational motion pattern around the other translational motion axis is superimposed, the electric discharge machining gap length formed between the machining electrode 1 and the workpiece 2 changes at relatively short time intervals. Also, since the direction of the translational movement and the plane of the auxiliary movement intersect, it is possible to satisfactorily agitate the chips present in the gap between electrical discharge machining.

Moreover, since the machining electrode 1 moves relative to the workpiece 2 at least in a plane perpendicular to the machining plane, the workpiece 2 and the machining electrode 1 can be moved relative to each other in various different directions. It will make you exercise,
Various relative movements of machining gap changes occur between the workpiece 2 and the machining electrode 1, and thereby, according to the above-described superimposed auxiliary motion according to the present invention,
It is possible to perform a pumping action to supply and drain the machining fluid in the machining hole 3 with a reciprocating movement of approaching and releasing between the electrode 1 and the workpiece 2, and simply stirs the chips, etc. in the machining hole 3. Not only that, but it can be removed more actively, so machining can be performed continuously without interruption, and machining efficiency can be significantly improved.

As a result, the occurrence of short circuit accidents in the discharge machining gap is drastically reduced, and the discharge machining efficiency is significantly improved.

In the above processing example, a case was explained in which a circular motion around the translation axis is performed as an auxiliary movement in a plane perpendicular to the translation axis, but the movement pattern of the auxiliary movement is not limited to this. It is sufficient that the rotational movement is not limited to the rotational movement within a plane in a direction perpendicular to the direction of translational movement in the processing plane and about an axis perpendicular to the plane. Furthermore, the present invention can also be implemented in the finishing process in which machining feed is performed in the Z-axis direction.

〔Effect of the invention〕

According to the machining method of the present invention, as described above, electric discharge machining such as collapsing machining is performed by relatively imparting a translational movement similar to collapsing machining along the contour line shape of the cross section of the electrode between the workpiece and the machining electrode. When performing this, due to the auxiliary movement that rotates around an axis in a plane perpendicular to the translation axis that is superimposed on this, the relative movement that occurs between the machining electrode and the workpiece causes the workpiece and the machining This causes the electrodes to move relative to each other in various different directions.
Various relative motions occur between the workpiece and the machining electrode, which change the machining gap, and this creates a pumping action that supplies and drains the machining fluid in the machining hole. It is possible to not only stir up chips, etc., but also to remove them more actively, so processing efficiency can be significantly improved, and good processing can be performed.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a machining electrode and a workpiece for explaining an example of the locus of translational motion during electric discharge machining according to the present invention, and FIG. 2 is a cross-sectional view of the translational motion shown in FIG. 1. FIG. 3 is a diagram showing a composite motion trajectory when auxiliary motions are superimposed, and FIG. 3 is a diagram showing another example of a composite motion trajectory.

Claims (1)

[Claims] 1. Proximity machining feed in a uniaxial direction facing each other is relatively applied between the workpiece and the machining electrode, and
Or in an electric discharge machining method in which, after machining by the machining feed, a translational movement of a predetermined amplitude is relatively applied between the electrode and the workpiece in a plane substantially perpendicular to the one axis, The translational movement causes the side surface of the electrode and the side surface of the machined hole in the workpiece to be closely opposed to each other by displacing the electrode relative to the workpiece by a predetermined minute distance in a direction perpendicular to the uniaxial direction. In addition to the relative motion sequentially along the contour shape of the electrode cross section perpendicular to the one axis, which is given as a state of rotation, the motion in a plane substantially perpendicular to the direction of the axis of motion along the contour shape An electrical discharge machining method characterized by superimposing auxiliary motion consisting of relative rotational motion with a minute displacement width around an axis. 2. The electric discharge machining method according to claim 1, wherein the auxiliary movement consisting of the rotational movement is intermittently superimposed on the movement along the contour shape at predetermined intervals.