JPH07285030A - Fine hole machining electric discharge machine - Google Patents

Abstract

PURPOSE:To reduce contact friction between a wire electrode and a guide so as to accomplish precise perforating work. CONSTITUTION:In a fine hole machining electric discharge machine in which one/plural intermediate guide/guides 4 is/are arranged in the middle part between an electrode fixing metal fitting 2 holding a rotary electrode 1 and a point guide 3 positioning the electrode point part, inside walls/an inside wall of a rotary electrode insertion hole 5 in the point guide 3 and/or the intermediate guide 4 are/is formed freely rotationally while setting a shaft center of an insertion hole 5 as the center. For a desired execution form of the insertion hole inside wall, a means installing an inside wall member 6 freely rotationally in a guide arm 8 via a bearing 7 can be employed. The inside wall member 6 is desiredly formed of ceramic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine mainly for fine hole machining. In the present invention, the terms holes and holes are used to include both.

[0002]

2. Description of the Related Art An electric discharge machine using a rotating wire electrode is widely used as a punching means for forming a fine hole or a fine hole in a workpiece. Rotating wire electrodes typically have a diameter of 1 mm
It consists of the following thin wires or pipes, 500-50
Use by rotating at 00 rpm. In order to accurately position the tip of the electrode at the processing site, a tip guide having an opening through which the electrode passes is attached near the tip. However, the rigidity of the wire electrode is low, and when the electrode is rotated, the intermediate portion between the electrode fixing metal fitting that holds the electrode and the tip guide makes an arc and swings, so that the tip of the electrode uses the tip guide as a supporting point. It shook like a pestle and hindered precision drilling.

[0003]

Recently, the machining accuracy has been improved and even a slight deflection of the tip of the electrode has become a problem, and the second and third parts are provided in the intermediate portion between the electrode fixing member and the tip guide.
Attempts have been made to provide a guide. Multistage guide for oblique holes described in Japanese Utility Model Publication No. 52-33995, Japanese Utility Model Application No. 61-56231 (Japanese Utility Model Application No. 62-168219).
A guide for a stainless steel plate described in a microfilm, Japanese Patent Laid-Open No.
The intermediate electrode guides described in JP-A-0-108234, the grease guide described in JP-A-1-164526, and the one or more intermediate guides described in JP-A-1-295723. However, recently, the number of fine processing has increased and the diameter of the electrode to be used has been reduced to 1 mm or less. Therefore, when the number of guides increases or the number of rotations increases, the power required for rotation increases, and the wire electrodes are easily damaged due to friction between the guides. Although the grease guide described above does not have such a problem, it has a drawback in that the positioning of the electrodes is not accurate. An object of the present invention is to provide an electric discharge machine for fine hole machining, which can reduce contact friction between a wire electrode and a guide and can perform a precise opening operation.

[0004]

The present invention will be described in detail with reference to FIG. According to the present invention, in order to achieve the above object, one or a plurality of intermediate guides 4 are provided in an intermediate portion between an electrode fixing metal fitting 2 that holds a rotating electrode 1 and a tip guide 3 that positions an electrode tip. In the electric discharge machine for fine hole machining, the inner wall of the rotary electrode through hole 5 of the tip guide and / or the intermediate guide is configured to be freely rotatable around the axis of the through hole. ,
Provide an electric discharge machine for small hole machining. Tip guide and /
As a preferred embodiment of the inner wall of the rotary electrode through hole of the intermediate guide, there is a means for attaching the inner wall member 6 to the guide arm 8 via the bearing 7 so as to freely rotate.
The inner wall member 6 is preferably made of ceramic.

[0005]

OPERATION AND EXAMPLE OF EMBODIMENT The present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram (including a partial cross section) of an embodiment of the present invention. The rotary electrode 1 of the electric discharge machine for fine hole machining is vertically movable, is held by the electrode fixing metal fitting 2, and can be rotated by the rotating device 9. A discharge servomotor or the like is used for the rotating device 9. At the time of punching, the rotary electrode 1 is inserted into each rotary electrode through hole 5 provided in the guide arm 8 of the intermediate guide 4 and the tip guide 3, and the tip of the electrode faces the workpiece 10 or during machining. It is positioned at a predetermined position such as a hole. If necessary, the guide arm 8 is attached so as to be movable up and down or left and right. The tip guide 3 positions the tip of the electrode, and the intermediate guide 4 has a function of suppressing the rotating contact of the rotating electrode 1. The relative position between the electrode tip and the processed material 10 can be adjusted on either the rotating electrode 1 or the processed material 9 side, or both. Usually, an XY stage is used for positioning the processed material 10, and a Z stage is used for positioning on the rotary electrode 1 side. The gap between the tip guide 3 and the adjacent intermediate guide 4 is important for precision drilling, and it is generally preferable that the gap does not exceed 25 mm. 25 mm
If it exceeds, the processed hole will become large and lack precision.

The inner wall member 6 of the rotary electrode through hole 5 of the electric discharge machine for machining a fine hole of the present invention is constructed so as to be freely rotatable around the axis of the through hole. During the perforation operation, the inner wall of the through hole 5 rotates together with the rotation of the rotating electrode, so that the rotating electrode 1 can be prevented from being damaged by the rubbing between the rotating electrode 1 and the inner wall member 6. The inner diameter of the through hole is the diameter of the rotary electrode 1, the processing accuracy,
Depending on the distance from the processed material 10, etc., the rotating electrode diameter is 1.0
2 to 1.5 times, preferably 1.05 to 1.3 times, electrode 1
The gap between the inner wall member 6 and the inner wall member 6 is usually selected to be several to several tens of μm. If the rotating electrode 1 is too small, damage to the rotating electrode 1 increases, and if it is too large, the deflection of the electrode tip tends to increase. The length of the through hole is preferably about 6 to 15 mm. An inner wall member 6 and a bearing 7 are used as means for freely rotating the inner wall of the through hole 5 about its axis.
It is preferable that the guide arm 8 is attached to the guide arm 8 via the so as to be freely rotatable. Using the inner ring of the bearing as the inner wall member is also included. The surface of the inner wall member 6 is preferably made of ceramic. A bearing having a ceramic inner ring or an inner ring having a ceramic coated inner surface may be attached to the guide arm. Examples of the ceramic used include metal oxides and nitrides such as alumina and zirconia. In the present invention, the inner walls of the rotary electrode through holes of all the guides are not always freely rotatable. Considering the position of the guide, the inner diameter of the through hole, etc., it is preferable that the guide be freely rotatable. In the present embodiment example, the inner wall of the through hole 5 of the intermediate guide 4 is configured to be freely rotatable.

Further, it is preferable to protect the rotary electrode by pouring a working liquid into the through hole 5 and utilizing it for lubricating the rotary electrode. Reference numeral 11 is an injection pipe for the working fluid. Kerosene as the processing liquid,
Water or the like is used.

[0008]

In the electric discharge machine for machining a fine hole of the present invention, since the inner wall of the rotary electrode through hole of the guide is freely rotated, friction between the electrode and the guide is reduced, and precise perforation is prevented by overheating the electrode. There is an effect that it can be carried out without causing wear.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an exemplary embodiment of the present invention.

[Explanation of symbols]

1: Rotating electrode 2: Electrode fixing bracket 3: Tip guide 4: Intermediate guide 5: Rotating electrode through hole 6: Inner wall member 7: Bearing 8: Guide arm 9: Rotating device 10: Work material
11: Working fluid injection pipe

Claims (3)

[Claims] 1. An intermediate portion between an electrode fixing metal fitting 2 for holding a rotating electrode 1 and a tip guide 3 for positioning an electrode tip portion.
Alternatively, in an electric discharge machine for fine hole machining provided with a plurality of intermediate guides 4, the inner wall of the rotary electrode through hole 5 of the tip guide and / or the intermediate guide can freely rotate around the axis of the through hole. The electric discharge machine for small hole machining, which is characterized in that 2. The inner wall member 6 of the rotary electrode through hole of the tip guide and / or the intermediate guide is attached to a guide arm 8 via a bearing 7 so as to be freely rotatable. The electrical discharge machine for fine hole machining described in. 3. The electric discharge machine for fine hole machining according to claim 1, wherein the inner wall member 6 of the rotary electrode through hole is made of ceramic.