JPS63102835A - Electrode for electric discharge machining - Google Patents

Abstract

PURPOSE:To prevent any hunting taking place when the electrode in the caption goes through a piercing hole so as to improve the efficiency of processing, by sticking the coating layer of an insulator to the inner wall surface of a tubular electrode. CONSTITUTION:Any sort of material can be employed as an insulating material for forming a coating layer 4 regardless whether it is inorganic or organic, provided that it can be scattered, as an electrode 1 is consumed. If some plastic material such as phenol resin is used, for instance, the coating layer 4 can be formed easily by sticking said material, under its softened state or state fused in solvent, to the inner wall surface 3 of the electrode 1. When this electrode 1 for electric discharge processing is used, the coating layer of an insulator stuck to the inner wall surface 3 of the tubular electrode 1 can prevent any shortcircuit taking place between the residual core 5 of a workpiece and the inner wall surface 3 of the electrode. Accordingly, the electric discharge processing can be carried out smoothly and quickly without allowing any hunting to be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a machining electrode used as a tool during electrical discharge machining.

(Prior art) Recently, for example, a tubular electrode (vibe electrode) has become more widely used as an electric discharge machining fff [i] used for machining small holes with a hole diameter of around 1#. became. This is because a high machining speed can be obtained by spouting the machining fluid from inside the 161 m.

(Problems to be Solved by the Invention) However, when using this tubular electrode, when performing through-hole machining on a workpiece W whose machining end side exhibits a curved surface shape, as shown in FIG. In this case, a short circuit 14 occurs between the residual axis 12 of the workpiece, which is unstable and shifts to the left and right, and the inner wall surface 13 of the electrode, resulting in a repeated hunting state in which machining does not progress, and the machining time increases. There was a problem that the width increased rapidly.

This invention solves the above-mentioned conventional problems, and aims to provide an electrode for electric discharge machining that can prevent hunting during the through-hole method and improve machining efficiency.

(Means for Solving the Problems) The electrode of the present invention is an electric discharge machining electrode characterized in that an insulating coating layer is attached to the inner wall surface of the tubular electrode.

The material of the insulator forming the coating layer in this invention may be inorganic or organic as long as it scatters as the electrode wears out, but if a plastic material such as phenol resin is used, it may be softened or This is preferable because the coating layer can be easily formed by adhering it to the inner wall surface of the electrode in a molten state. The thickness of this insulating coating layer is preferably less than the discharge clearance (for example, about 10 μm).

<Function> In the electrode for electric discharge machining of the present invention, the coating layer of insulator attached to the inner wall surface of the tubular electrode is formed between the residual axis of the workpiece and the inner wall surface of the electrode when handling the through hole. Prevent short circuits from occurring.

(Actual Sub-Example) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, 1 is a tubular electrode with an outer diameter of 1. This is a well-known brass pipe electrode from Ottun. The tip 2 of the electrode 1 is immersed in a phenolic resin paint dissolved in a solvent and the paint is sucked up to form a coating layer of the paint on the inner wall surface 3 of the electrode, which is then allowed to dry and thicken. A coating layer 4 having a thickness of approximately 10 μm was formed. The paint adhering to the end face and outer peripheral surface of the tip 2 of the electrode is removed by wiping with a solvent.

Using the electrode with the above configuration, as shown in Fig. 3, a through-hole was machined on a workpiece WNJ quality = SUS> with a curved surface on the finished side. Even if the residual shaft core 5 becomes unstable, a short circuit between the inner wall surface 3 and the residual shaft core 5 will not occur due to the interposition of the coating layer 4, and electrical discharge machining can be performed smoothly and quickly without causing hunting. Ta. Note that the electric discharge machining of the through hole 6 is performed by electric discharge between the outer wall surface 7 of the electrode 1 and the end surface of the tip portion 2 and the workpiece W.

The present invention is not limited to the above-mentioned embodiments. For example, the coating layer 4 on the inner wall surface 3 of the electrode is formed by adhering and solidifying an insulator to the entire inner and outer periphery of the electrode 1, and then repainting the outer periphery and end surface. This may be done by a method such as polishing. Further, the present invention can be applied to electrodes for electrical discharge machining, such as rectangular or polygonal tubular electrodes, in addition to cylindrical electrodes, which are used for machining through-holes of irregular shapes other than circular.

(Effects of the Invention) As explained above, according to the present invention, the coating layer of the insulating material provided on the inner wall surface of the electrode is connected to the residual axis of the workpiece and the inner wall surface of the electrode when handling the hole. This prevents the occurrence of short circuits between the holes, which prevents hunting during through-hole drilling, and reduces electrical discharge machining time, which greatly contributes to shortening the takt time on mass production lines.

[Brief explanation of the drawing]

FIG. 1 is a front (partially cut away) view of a main part of an electrode for electric discharge machining showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view without showing the first configuration. 1... Electrode, 3... Inner wall surface, 4... Coating layer.

Claims (1)

[Claims] An electric discharge machining electrode characterized by having an insulating coating layer adhered to the inner wall surface of a tubular electrode.