JPH0557615A - Removing method of degenerated layer for electric discharge machining - Google Patents

Abstract

PURPOSE:To remove a degenerated layer generated on the worked surface of a work at electric discharge machining which is an important factor for causing cracks on the base material. CONSTITUTION:A degenerated layer 7 generated on the worked surface of a work 10 at electric discharge machining can be perfectly removed uniformly in a short time, by opposing a working nozzle 11 manufactured to fit the surface form of the work 10 and having a plurality of blow-off holes 4 to the surface to be worked of the work 10, and blowing compressed air 1 containing abrasive grains 9 from the blow-off holes 4 so as to hit the abrasive grains 9 on the surface to be worked of the work, or by oscillating the working nozzle 11 or the work 10 by ultrasonic wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an electric discharge machining deteriorated layer applied after electric discharge machining of engine parts, turbine blades and the like.

[0002]

2. Description of the Related Art A conventional apparatus used for electric discharge machining is shown in FIG.
As shown in FIG. 3, a container 40 in which the work 30 is arranged and filled with the machining liquid 32, an electrode 33 facing the electric discharge machining surface 39 of the work 30 and connected to a power source 31, an electric discharge machining control device 34, and a hydraulic tank. 35 to which the hydraulic pump 36 is connected, and the electrode 3 connected to the valve 37.
It was equipped with the electric discharge machine main body 38 to which 3 was joined.

In the above, in the electric discharge machining, a voltage is applied from the power source 31 between the electrode 33 and the electric discharge machining surface 39 of the work 30 to conduct electricity, and at the same time, the electric discharge machine main body 38
With this, the electrode 33 is processed while being moved in the X-, Y-, and Z-axis directions, and a complicated curved surface shape can be processed.

[0004]

In the conventional electric discharge machining, a brittle material, particularly a material in which cracks are likely to develop due to thermal stress caused by electric discharge machining, is shown in FIG. ), (B), the carbon in the working fluid (usually paraffinic oil) 32 enters the part of the electric discharge machined surface 39 of the work 30 that has been remelted by the electric discharge arc 42, and then is rapidly cooled and solidified to be hard. A brittle embrittlement layer (altered layer) 43 was formed with a thickness of several μm to several tens of μm, and at the same time, a hexagonal microcrack 41 was generated, and sometimes a crack reaching the base material was generated. In addition, when the use condition is accompanied by fatigue start / stop, this tendency is more remarkable, which is a problem to be improved in terms of use durability.

Therefore, it is necessary to remove the electric discharge machining deteriorated layer 43, but the electric discharge machining deteriorated layer 43 is several μm.
Since it is thin and hard and brittle, it takes a long time to mechanically remove it, and in addition, it is difficult to remove a complicated and narrow portion, and there has conventionally been no effective method for removing the deteriorated layer 43. ..

The present invention is intended to solve the above problems.

[0007]

According to the method for removing an electric-discharge-machining deteriorated layer of the present invention, a machining nozzle adapted to the surface shape of a work is manufactured, a plurality of nozzles are provided with the nozzle, and the nozzle is compressed from the nozzle. It is characterized in that abrasive grains accelerated by air are wiped and polished, and liquid honing is performed while ultrasonically vibrating the processing nozzle or the work.

[0008]

In the above, the processing nozzle having a plurality of blowing holes, which is manufactured according to the surface shape of the work, is disposed so as to face the working surface of the work, and the grinding is performed through the above-mentioned blowing holes while moving up and down or rotating. Compressed air containing particles is blown onto the machined surface of the work, and is applied to the deteriorated layer of the machined surface of the work generated by electric discharge machining to gradually remove it.

At the time of removing the deteriorated layer, the processing nozzle or the work is ultrasonically vibrated, whereby the abrasive grains are uniformly applied to the processed surface of the work, so that the deteriorated layer is uniformly removed in a short time. To be done.

As described above, it becomes possible to uniformly and completely remove the deteriorated layer generated on the work surface of the workpiece during the electric discharge machining in a short time.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an example of a method of removing an electric discharge machining deteriorated layer of a cylinder head for a diesel engine, and FIG. 2 shows a polishing mechanism by ultrasonic honing liquid honing.

In this embodiment shown in FIGS. 1 and 2, a processing nozzle 11 is manufactured in accordance with a processing surface shape of a cylinder head 10 which is a work, and a plurality of blowing holes 4 are provided in the nozzle 11 and the same hole is formed. The abrasive grains 9 accelerated by compressed air from No. 4 are sprayed onto the machining surface of the cylinder head 10, and the machining nozzle 11 or the cylinder head 10 is ultrasonically vibrated to perform liquid honing.

In the above, the cylinder head 10 to be subjected to the liquid honing after the electric discharge machining is put into the dedicated machining drum 12 filled with the machining fluid 5.

The processing nozzle 11 for performing the liquid honing processing of the cylinder head 10 is connected to the main body of the honing processing apparatus and is replaceably attached to the tip of the processing head 2 which can move up and down or rotate. Compressed air 1 containing 9 passes through the inside of the processing head 2 and is blown out from the blowing hole 4 of the processing nozzle 11, and the abrasive grains 9 are blown onto the processing surface of the cylinder head 10.

An ultrasonic vibrator 6 is attached to the bottom of the processing drum 12, and the vibrator 6 vibrates the cylinder head 10 at a high frequency through the working liquid 5. The abrasive grains 9 sprayed on the processed surface of the cylinder head 10 hit the deteriorated layer 7 at high speed to gradually remove the deteriorated layer 7 as shown in FIG.

Further, since the cylinder head 10 is ultrasonically vibrated, the abrasive grains 9 are evenly hit and polished,
The deteriorated layer 7 can be uniformly removed in a short time, and
It is possible to completely remove the deteriorated layer by adjusting the honing time, the pressure of the compressed air 1, and the size and the mixing amount of the abrasive grains 9.

Further, since the roughened abrasive grains, the dirt, and the deteriorated layer components removed are discharged to the outside through the discharge valve 3, the honing speed can be made uniform and the quality is good.

As described above, it becomes possible to completely remove the deteriorated layer generated on the processed surface of the cylinder head during the electric discharge machining in a short time.

In this embodiment, the cylinder head, which is the work, is ultrasonically vibrated, but the same effect can be obtained by vibrating the machining nozzle.

[0020]

EFFECT OF THE INVENTION The method of removing an electric discharge machined altered layer of the present invention is
A processing nozzle, which is manufactured according to the surface shape of the work and has a plurality of blowing holes, faces the work surface of the work,
Compressed air containing abrasive grains is blown out from the blowout hole,
By applying abrasive particles to the work surface of the work and ultrasonically vibrating the work nozzle or work, the deteriorated layer generated on the work surface of the work during electric discharge machining can be uniformly and completely removed. It is possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method for removing an electric discharge machined deteriorated layer according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a mechanism for removing an altered layer according to the above-described embodiment.

FIG. 3 is an explanatory diagram of conventional electric discharge machining.

FIG. 4 is an explanatory diagram of generation of a deteriorated layer and a crack in conventional electric discharge machining, showing (a) rough machining and (b) finishing machining.

[Explanation of symbols]

 1 Compressed Air 2 Processing Head 3 Exhaust Valve 4 Blow-out Hole 5 Processing Liquid 6 Ultrasonic Shaker 7 Deteriorated Layer 9 Abrasive Grain 10 Cylinder Head 11 Processing Nozzle 12 Processing Drum

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masanobu Shinohara 1-1, Atsunoura-cho, Nagasaki-shi Nagasaki R & D Co., Ltd. (72) Inventor Akio Sasada 5-7 Atsunoura-cho, Nagasaki-shi, Nagasaki Nagahishi Inside Engineering Co., Ltd.

Claims (1)

[Claims] 1. A processing nozzle is manufactured according to the surface shape of a workpiece, and a plurality of blowing holes are provided in the nozzle. Abrasive grains accelerated by compressed air are blown from the blowing holes to polish the work nozzle or A method for removing a deteriorated layer by electrical discharge machining, which comprises performing liquid honing while vibrating a work ultrasonically.