JPH01289616A - Electric discharge machine - Google Patents

Abstract

PURPOSE:To continuously supply working fluid and quickly discharge machining chips from a machining portion by providing second through holes besides a first through hole on a second electrode part, and further providing discharge grooves on the outer peripheral surface of the second electrode part on which the second through holes have their open ends. CONSTITUTION:On the bottom end face of a first electrode part 12, a second electrode part 13 whose cross-sectional area is larger than that of the first electrode part is provided integrally with the first electrode part, and a first through hole 14 is drilled such that it penetrates both the electrode parts 12, 13 from the top side to the bottom side. Further, second through holes 15 are provided so that they have open ends on the electric discharge surface of the second electrode part 13, and even after the first electrode part 12 passes through a work, working fluid is continuously supplied through the second through holes 15 to a machining portion. Discharge grooves 16, 17 are formed from the open ends of the second through holes 15 to the bottom end side of the second electrode part 13, and machining chips are discharged through the discharge grooves 16, 17 from the machining portion to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electrical discharge machining apparatus for drilling holes in, for example, steel material.

(Prior art) Generally, when drilling holes in steel materials by electric discharge machining, a step part is created in the middle by using a conductive straight electrode made of, for example, Cu, or by forming a thinner tip and thicker proximal end. A modified tool electrode was used. In addition, for supplying machining fluid and discharging machining debris, machining fluid may be jetted out through a jet hole penetrated from the base end to the distal end of the tool electrode, or
Or, on the contrary, it is configured to suck in air.

However, when electrical discharge machining is performed on a steel material using a conductive electrode such as Cu, considering only one discharge during a pulse discharge, the discharge concentrates at one point, increasing the energy density and forming deep microcracks. There was something.

In addition, since the jet hole drilled in the tool electrode is drilled from the base end to the tip side, when the tip of the tool electrode passes through the workpiece, the inner periphery of the hole on the workpiece side The supply of machining liquid to the surface and the discharge of machining debris were sometimes insufficient, resulting in a decrease in the precision of the machined surface.

(Problems to be Solved by the Invention) In a tool electrode formed of a conductive material, electric discharge against a workpiece tends to concentrate at one point, and microcracks are likely to occur. In addition, since the jet hole through which the machining fluid flows is penetrated from the tip to the base end, the machining fluid is not supplied to the circumferential surface of the machining hole after passing through the workpiece, resulting in insufficient discharge of machining debris. There was a problem that the surface accuracy deteriorated.

This invention has been made in view of the above circumstances, and provides an electric discharge machining device that can prevent the occurrence of microcracks and also obtain high machined surface accuracy by quickly discharging machining debris from the machined area. The purpose is to

[Structure of the invention]

(Means for Solving the Problems) This invention provides a second electrode portion having a larger cross-sectional area than the first electrode portion integrally provided on the proximal end side of the first electrode portion,
A first through hole is formed that penetrates from the distal end side to the proximal end side of the first and second electrode sections, and is opened in the discharge surface of the second electrode section and communicates with the first through hole. a second through hole is provided, and a discharge groove is formed between the axial ends of the second electrode portion so as to correspond to the opening of the second through hole;
The electrical discharge machining apparatus is characterized in that a semiconductor layer is provided on the discharge surface of the second electrode section.

(Function) By providing the second through hole in the discharge surface of the second electrode part, machining fluid is supplied to the machining area even after the first electrode part penetrates, and the second through hole Since the groove is formed from the opening to the proximal end of the second electrode section, processing waste can be quickly discharged. Further, the semiconductor layer formed on the discharge surface of the second electrode portion prevents concentration of discharge, and a highly accurate machined surface can be obtained.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

First, to explain the general structure of the electric discharge machining apparatus 1, a main spindle head 2 is provided on a main body (not shown), and a main spindle 3 having an axis in the vertical direction is provided on this main spindle head 2. A rotating device 4 is provided at the upper end. Further, a cylinder 5 is provided between the main shaft 3 and the rotating device 4 to move the main shaft 3 up and down.

Furthermore, a pump 6 for supplying machining fluid is connected to the main shaft 3, and the flow path of this machining fluid is connected to the tool electrode 7.
It is connected to the.

Further, a processing table 8 is provided below the spindle head 2. A relief hole 9 is bored in the center of the processing table 8 and passes through the hole in the vertical direction, and the main shaft 3 is located at a position corresponding to the upper side of the relief hole 9.

Then, the workpiece 10 is fixedly supported on the machining table 8 and electrical discharge machining is performed.The structure for generating electric discharge is such that a voltage is applied between the tool electrode 7 and the workpiece 10. A high voltage power supply 11 is connected.

When drilling a through hole in the workpiece 10, the high voltage power supply 11 generates an electric discharge between the tool electrode 7 and the workpiece 10, and the pump 6 supplies machining fluid to the workpiece. , and the tool electrode 7 is rotated by the rotating device 4 and fed in the vertical direction by the cylinder 5 to perform electrical discharge machining.

The tool electrode 7 of this electric discharge machining apparatus 1 is made of a conductive material such as Cu, and has first and second electrode parts 12,13. The tool electrode 7 is formed in a cylindrical shape, with the distal end forming the first electrode section 12 and the base end of the first electrode section 12 forming the second electrode section 13. . The diameter of this second electrode section 13 is ? C! It is formed larger than the diameter of the ClO2 pole part 12, and a stepped part is formed in the part where both are continuous.

A first through hole 14 is formed from the proximal end surface to the distal end surface of the tool electrode 7 formed in the first and second electrode sections 2.13. A flow path for machining fluid from the pump 6 of the electrical discharge machining apparatus is connected to the base end side of the first through hole 14.

Further, a plurality of second through holes 15, . . . are bored in the circumferential surface of the second electrode portion 13. These second through holes 15, . here,
The second through holes 15, . . . have an opening angle of, for example, 180 mm in the circumferential direction, and are sequentially formed at equal intervals in the longitudinal direction.

In addition, the peripheral surface portion of the second electrode portion 13 where the second through-holes 5, . . .
A discharge groove] 6.17 is provided. This discharge groove 16
, ]7 are provided in the openings of the second through holes 15, .

Here, the discharge grooves 16, 17 are cut out from the front part in the rotational direction in the tangential direction of the circumferential surface, and are cut out so that the tangential line and the radial line of the cylindrical shape are perpendicular to each other. Since the discharge grooves 16 and 17 having such a shape have a surface perpendicularly intersecting the rotational direction at the rear in the rotational direction, they have the property of scraping off machining debris and can efficiently discharge machining debris.

An St layer 18 as a semiconductor layer is formed on the entire outer peripheral surface of the second electrode section 13.

When electrical discharge machining is performed using the electrical discharge machining apparatus 1 formed in this manner, electrical discharge machining is first started at the tip of the first electrode portion 12. At this time, the L liquid is added to the first through hole 1.
4, and is pumped to two parts of the workpiece 10. Here, since the first electrode section 12 is made of Cu, it is easy to cause local electric discharge and the energy density of the electric discharge is high, so that electric discharge machining is performed as so-called rough machining.

Then, as the electric discharge machining progresses, the tool electrode 7 is gradually lowered by the cylinder 5, and the second electrode section 13 starts electric discharge machining on the workpiece 10. At this time, the first electrode portion 12 passes through the workpiece 10, and the machining fluid ejected from the first N through hole 14, which is opened at the tip, is not supplied to the machining area. Although the situation is
"2. Second through hole 15 on the circumferential surface of the second electrode part 13,
... is provided, so this second through hole 15,
Through this, the supply of machining liquid to the machining area C is continued. Furthermore, this second electrode portion 13 has a discharge groove 16.1.
7 are formed, so that the second through holes 15,...
・The liquid flows out along these discharge grooves 16, 7. This makes it possible to efficiently discharge machining waste four times.

Furthermore, the entire discharge surface of this second electrode section 13 is covered with Si.
Since the layers are formed, a more uniform discharge is generated than in the case of the discharge at the first electrode section 12 described above. That is, by dispersing the discharge energy over the entire surface, the density of the discharge energy generated for each pulse can be kept low, so that microcracks can be kept small and machining accuracy can be improved.

It is known that when machining cemented carbide, using an electrode made of A or g-W alloy allows for highly accurate pressurization.
The second electrode part 13 is made of u-W alloy
By forming the g-W alloy, highly accurate electrical discharge machining can be performed.

At this time, no S1 layer is provided on the discharge surface of the second electrode portion 1'3.

In addition, when performing hole machining, highly accurate hole machining can be performed by using an electrode made of a material corresponding to the material of the workpiece and configuring the structure as shown in the above embodiment.

〔Effect of the invention〕

By providing the second through hole in addition to the first through hole in the second electrode portion, the machining fluid can be supplied without strain. In addition, a discharge groove is formed on the circumferential surface of the second electrode part in which the second through hole is formed, so that machining waste can be quickly discharged from the machining area, and electric discharge can be stabilized. . Furthermore, by forming a semiconductor layer on the second electrode part, it prevents localized discharge and disperses the discharge over the entire surface, reducing microcracks and enabling highly accurate discharge machining. We can provide electrical discharge machining equipment that can perform

[Brief explanation of the drawing]

FIGS. 1 to 4 show an embodiment of this invention,
Figure 1 is a front view showing the schematic configuration of the electrical discharge machining device;
The figure is a side view of the tool electrode, and Figure 3 is m- in Figure 2.
■Front view seen from the lined part, Figure 4 is I in Figure 2
FIG. 3 is a sectional view taken along line V-IV. 1... Electrical discharge machining device, 7... Tool electrode, 12...
1st electrode part, 13... 2nd electrode part, 14... 1st through hole, 15... 2nd through hole, 16.17...
- Exhaust groove, 18...Si layer (semiconductor layer). Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] In an electrical discharge machining device that has a tool electrode formed into a cylindrical shape made of a conductive material and performs electrical discharge machining by supplying machining fluid while rotating the tool electrode in the circumferential direction, the tool electrode is connected to the workpiece. a first electrode part that starts electric discharge machining first; and a second electrode part that is integrally provided on the proximal end side of the first electrode part and has a larger cross-sectional area than the first electrode part. , a first through hole bored from the distal end side to the proximal end side of the first and second electrode sections, and a first through hole opened in the discharge surface of the second electrode section and communicated with the first through hole. a second through hole and a discharge groove formed between the axial end portions of the second electrode portion so as to correspond to the opening of the second through hole; An electric discharge machining apparatus comprising: a semiconductor layer formed on a discharge surface.