WO2018066877A1

WO2018066877A1 - Hole processing method

Info

Publication number: WO2018066877A1
Application number: PCT/KR2017/010712
Authority: WO
Inventors: 김태형
Original assignee: 한화테크윈주식회사
Priority date: 2016-10-05
Filing date: 2017-09-27
Publication date: 2018-04-12
Also published as: KR102391949B1; KR20180037835A

Abstract

Provided is a hole processing method, according to an aspect of the present invention, the method comprising the steps of: preparing a conductive workpiece having an insulating layer formed thereon; disposing, on the insulating layer, a discharge guide member including a consumable conductor portion and an insulating portion disposed so as to surround the outer periphery of the consumable conductor portion; disposing a discharge electrode above the consumable conductor; and forming a hole in the workpiece by lowering the discharge electrode while performing electric discharge machining by applying electric power to the discharge electrode and the workpiece.

Description

Hole processing method

The present invention relates to a hole processing method.

When the hole is formed in the member to be formed with the insulating layer, it is generally difficult to perform the electric discharge machining due to the insulating layer, so that the hole is formed by laser processing or the like instead of the electric discharge machining.

When the hole is formed by laser processing or the like, it is difficult to control the hole processing depth, which may damage other parts of the member to be processed, and the quality thereof is also lower than that of the electric discharge machining.

On the other hand, Japanese Laid-Open Patent Publication No. 1988-150109 discloses a technique for performing electrical discharge machining by using a conductor layer in which a conductor layer is disposed on an electrical insulator. However, the technique disclosed in Japanese Unexamined Patent Publication No. 1988-150109 has a low quality of the hole formed due to uneven roughness of the inner circumferential surface of the hole to be processed, and the re-melting layer formed by electric discharge machining also becomes nonuniform, causing cracks in the discharged part. There is room for problems.

According to an aspect of the present invention, the main object of the present invention is to implement a hole processing method capable of processing holes of improved quality.

According to an aspect of the present invention, there is provided a conductive member having an insulating layer formed thereon; and a discharge guide member including a consumable conductor portion and an insulation portion disposed to surround an outer circumference of the consumable conductor portion. And disposing a discharge electrode above the consumable conductor; and applying the power to the discharge electrode and the member to be discharged to lower the discharge electrode while performing discharge machining. It provides a hole processing method comprising the step of forming a hole.

According to the hole processing method according to an aspect of the present invention, the roughness of the formed inner peripheral surface of the hole is uniform by the insulating portion of the discharge guide member during the electrical discharge machining, the quality of the hole is improved, the thickness of the redissolution layer resulting from the electrical discharge machining The uniformity has the effect of reducing the occurrence of cracks in the machined part.

1 is a schematic perspective view illustrating a hole of a turbine blade to which a hole machining method according to an embodiment of the present invention is applied.

2 is a schematic perspective view showing a discharge guide member according to an embodiment of the present invention.

3 is a schematic perspective view showing a discharge guide member according to another embodiment of the present invention.

4 is a schematic perspective view showing a state in which the discharge guide member has a tape shape and the tape-shaped discharge guide member is wound on a reel according to another embodiment of the present invention.

FIG. 5 is a schematic perspective view illustrating a state in which a discharge guide member is disposed on a surface of a turbine blade according to an embodiment of the present invention and a discharge electrode is approached for discharge machining.

FIG. 6 is a schematic cross-sectional view taken along the line VV of FIG. 5.

FIG. 7 is a schematic cross-sectional view illustrating a state in which discharge machining is started by using a discharge guide member and a discharge electrode according to an embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view illustrating a state in which a portion of an insulating layer and a member to be removed are removed by performing a discharge machining using a discharge guide member and a discharge electrode according to an embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of a hole formed in a member to be processed by performing discharge machining using the discharge guide member and the discharge electrode according to an exemplary embodiment of the present invention.

FIG. 10 is a schematic perspective view showing a tape-shaped discharge guide member shown in FIG. 4 on the surface of a turbine blade according to an embodiment of the present invention and approaching a discharge electrode for discharge machining.

Here, the consumable conductor portion may have a circular shape, and the insulation portion may have a ring shape surrounding an outer circumference of the consumable conductor portion.

Here, the discharge guide member may have a tape shape.

Here, the discharge guide member may include a plurality of consumable conductor parts.

Here, the surface attached to the insulating layer of the surface of the discharge guide member may be an adhesive surface.

Here, the insulation portion may be lowered by gravity during the electrical discharge machining.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, duplication description is abbreviate | omitted by using the same code | symbol about the component which has substantially the same structure.

1 is a schematic perspective view showing a hole of a turbine blade to which a hole machining method according to an embodiment of the present invention is applied, and FIG. 2 is a schematic perspective view showing a discharge guide member according to an embodiment of the present invention. 3 is a schematic perspective view showing a discharge guide member according to another embodiment of the present invention, Figure 4 is a discharge guide member according to another embodiment of the present invention has a tape shape, the tape-shaped discharge A schematic perspective view showing how the guide member is wound on a reel.

In FIG. 1, a hole H is formed in a turbine blade B of a gas turbine, and the hole H of the turbine blade B is a cooling hole, through which cooling fluid flows. It is possible to lower the temperature of the turbine blade (B).

The hole processing method according to the present embodiment can be applied to form the hole (H) of the turbine blade (B). That is, since the turbine blade B applied to the gas turbine is used at a high temperature, a heat shield coating layer, which is an insulating layer N of ceramic material, is formed on the surface of the turbine blade B for protection from high temperature. However, since the electrical discharge machining cannot be performed immediately by the insulating layer N, the discharge guide member 110 according to the present embodiment is required, which will be described later.

The hole processing method according to the present embodiment is applied to form the hole H of the turbine blade B, but the present invention is not limited thereto. That is, the hole processing method according to the present invention can be applied without limitation, if the insulating layer is formed and the member to be made of a conductive material, it can be naturally applied to other kinds of member other than the turbine blade. That is, the hole processing method according to the present invention may be applied to parts of various fields such as compressor parts, ship parts, aircraft parts, etc., which are composed of conductive parts having an insulating layer formed on a surface thereof.

2 is a schematic perspective view showing a state of the discharge guide member 110 according to the present embodiment.

The discharge guide member 110 according to the present embodiment includes a consumable conductor portion 111 and an insulation portion 112. The consumable conductor portion 111 has a circular shape, and the insulation portion 112 is a consumable conductor. It has the shape of the ring surrounding the outer periphery of the part 111.

The consumable conductor part 111 causes the discharge electrode G and the discharge spark during the discharge machining to perform the discharge machining.

The consumable conductor portion 111 is made of a conductive material and has a circular shape. The consumable conductor part 111 may include a conductive material, and the consumable conductor part 111 may have a conductive property, and the specific kind of the material is not particularly limited. For example, the conductive material of the consumable conductor part 111 may be a metallic material such as iron, copper, silver, or a synthetic resin material such as conductive plastic.

The consumable conductor portion 111 according to the present embodiment has a circular shape, but the present invention is not limited thereto. That is, there is no particular limitation on the shape of the consumable conductor part according to the present invention. For example, the shape of the consumable conductor part according to the present invention may be various shapes such as an oval, a triangle, and a polygon.

The insulation part 112 is comprised so that the outer periphery of the some consumable conductor part 111 may be enclosed. That is, the hole 112a is formed in the insulating part 112, and the consumable conductor part 111 is inserted in the hole 112a. In addition, the lower surface of the insulating portion 112 has an adhesive surface 112b, so that it is easy to attach to the insulating layer (N).

According to the present embodiment, only the lower surface of the insulating portion 112 has the adhesive surface 112b, but the present invention is not limited thereto. That is, according to the present invention, the adhesive surface 112b may not be formed on the lower surface of the insulating part 112, and in this case, the adhesive surface may be formed on the lower surface of the consumable conductor part 111. In addition, according to the present invention, an adhesive surface may be formed on both the consumable conductor part 111 and the insulating part 112 of the discharge guide member 110. In addition, according to the present invention, the discharge guide member 110 may be attached to the insulating layer N by using a separate adhesive or an adhesive material without forming an adhesive surface at all.

Moreover, it is preferable to comprise the insulating part 112 from the heat resistant material which does not melt even at the high temperature during electric discharge machining. For example, PEEK (polyeheretherke tone), PES (polyethersulfone), liquid crystal polymer (LCP), nylon nanocomposites, other polyimide (polyimide, polya mideimide, polyetherimide, PI), PPS (polyphenylenesulfide) and the like can be applied.

According to the present exemplary embodiment, the consumable conductor part 111 of the discharge guide member 110 has a circular shape, and the insulating part 112 has a ring shape surrounding the outer circumference of the consumable conductor part 111. The invention is not limited to this. That is, the shapes of the consumable conductor part and the insulating part according to the present invention may have various shapes. For example, according to another embodiment of the present invention, as shown in FIG. 3, the consumable conductor portion 211 of the discharge guide member 210 has an elliptical shape, and the insulating portion 212 has a consumable conductor portion ( It may have a shape surrounding the outer periphery of 211 and having a rectangular edge as a whole.

In addition, according to another embodiment of the present invention, as shown in Figure 4, the discharge guide member 310 may have a tape shape as a whole. 4 illustrates a state in which the discharge guide member 310 is wound around the reel R. As shown in FIG. In this case, the insulating part 312 is configured to surround the outer circumference of the plurality of consumable conductor parts 311, and for this purpose, a plurality of holes 312a are formed in the insulating part 312, and consumables are formed in the holes 312a. The conductor portion 311 is sandwiched and disposed. In addition, the lower surface of the insulating portion 312 may have an adhesive surface 312b, and in this case, the adhesive surface 312b may be easily attached to the insulating layer N. In addition, the user may cut and use the tape-shaped discharge guide member 310 in the form of a

discharge guide member

110, 210 shown in Figs.

Hereinafter, a hole machining method according to an embodiment of the present invention will be described with reference to FIGS. 5 to 9.

FIG. 5 is a schematic perspective view illustrating a state in which a discharge guide member is disposed on a surface of a turbine blade and a discharge electrode is approached for discharge machining, and FIG. 6 is a line V-V of FIG. 5. A schematic cross-sectional view cut along the view. FIG. 7 is a schematic cross-sectional view illustrating a state in which discharge machining is started using a discharge guide member and a discharge electrode according to an embodiment of the present invention, and FIG. 8 is a discharge guide member according to an embodiment of the present invention. FIG. 9 is a schematic cross-sectional view illustrating a state in which an insulating layer and a part of a member are removed by performing discharge machining using a discharge electrode. FIG. 9 is a view illustrating a discharge guide member and a discharge electrode according to an embodiment of the present invention. It is a schematic sectional drawing which shows the state in which the hole was formed in the to-be-processed member by performing electric discharge machining.

First, the worker prepares the turbine blade B which is the to-be-processed member in which the insulating layer N was formed (step S101).

Next, the worker places the discharge guide member 110 including the consumable conductor portion 111 and the insulation portion 112 in the insulating layer N (step S102). At this time, the adhesive layer 112b on the lower surface of the insulating part 112 is attached to the insulating layer N, but the consumable conductor part 111 is attached to the "hole processing target part C" of the turbine blade B. To be deployed in correspondence.

Next, the worker arranges the discharge electrode G above the consumable conductor portion 111 (step S103). The state corresponding to this step is shown in FIGS. 5 and 6.

Then, the worker applies the power to the discharge electrode G and the turbine blade B to lower the discharge electrode G while performing discharge machining, thereby forming a hole in the turbine blade B as a member to be processed ( Step S104).

7 to 9, step S104 will be described in more detail as follows.

As shown in FIG. 7, when power is applied to the discharge electrode G and the turbine blade B (for example, the discharge electrode G is used as the cathode and the turbine blade B is used as the anode). Can be applied and vice versa), and spark sparks are generated by the consumable conductor part 111, and the insulating layer N is gradually removed as the consumable conductor part 111 melts.

When the worker continues discharge processing while gradually lowering the discharge electrode G, as shown in FIG. 8, the hole processing target portion C of the insulating layer N and the turbine blade B is also gradually removed. At this time, as the hole processing target portion C of the insulating layer N and the turbine blade B is gradually removed, the insulating portion 112 is also lowered by gravity, and the hole 112a of the insulating portion 112 is lowered. The discharge electrode G is fitted.

This discharge machining process is continued until the end of the processing of the hole (H), as shown in Figure 9, during the discharge machining process is discharged due to the presence of the insulating portion 112 falling with the discharge electrode (G). The spark is adjusted and the direction of the discharge spark is also guided. That is, during the electrical discharge machining process, the insulation layer N and the hole processing target portion C of the turbine blade B are melted and removed, and the insulation portion 112 also gradually descends due to gravity, and the downward movement of the insulation portion 112 is performed. Since silver is made with the fall of the discharge electrode G, the discharge spark by the discharge electrode G is adjusted suitably, and the direction is guided suitably. As a result, not only the illuminance of the inner circumferential surface of the formed hole H is uniform, but also the thickness of the redissolved layer generated by the electric discharge machining can be made uniform.

As described above, in the hole processing method according to the present embodiment, holes are formed by electric discharge machining by performing electric discharge machining using the discharge guide member 110 including the consumable conductor part 111 and the insulating part 112. Since the illuminance of the inner circumferential surface of (H) can be made uniform, high quality holes can be realized. Therefore, if the fluid flows through the hole (H) formed in the member to be processed, since the roughness of the inner circumferential surface of the hole is uniform, there is an advantage that the flow of the fluid passing through the hole (H) can be smoothly performed.

In addition, in the hole machining method according to the present embodiment, re-dissolution generated by discharge machining is performed by performing discharge machining using the discharge guide member 100 including the consumable conductor part 111 and the insulating part 112. Since the thickness of the layer can be made uniform, cracking of the member to be processed can be prevented. In general, a method of slowing the discharge machining speed is known as a method of making the thickness of the redissolved layer uniform to prevent cracking. According to the present embodiment, since the discharge guide member is used, the discharge machining can be performed at a high speed. The speed of the machining process can be improved.

Meanwhile, FIG. 10 shows the tape-shaped discharge guide member 310 shown in FIG. 4 disposed on the surface of the turbine blade B according to one embodiment of the present invention, and the discharge electrode G is approached for discharge machining. It is a schematic perspective view showing the appearance, the hole processing method in that case may be applied as it is or the modified step S101, step S102, step S103, step S104 as it is, a detailed description thereof will be omitted.

While aspects of the present invention have been described with reference to the embodiments shown in the accompanying drawings, this is merely exemplary, and various modifications and equivalent other embodiments are possible from those skilled in the art. You will understand the point. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

According to one aspect of the present invention, it can be applied to the industry using the hole processing method.

Claims

Preparing a conductive member to be formed with an insulating layer formed thereon;

Disposing a discharge guide member on the insulating layer, the discharge guide member including a consumable conductor part and an insulating part disposed to surround an outer circumference of the consumable conductor part;

Disposing a discharge electrode above the consumable conductor; And

And forming a hole in the member to be processed by lowering the discharge electrode while applying electric power to the discharge electrode and the member to be discharged.
The method of claim 1,

The consumable conductor part has a circular shape, and the insulating part has a ring shape surrounding an outer circumference of the consumable conductor part.
The method of claim 1,

And the discharge guide member has a tape shape.
The method of claim 1,

And the discharge guide member comprises a plurality of consumable conductor parts.
The method of claim 1,

The hole processing method of the surface of the said discharge guide member adhering to the said insulating layer is an adhesive surface.
The method of claim 1,

The hole processing method in which the said insulating part falls by gravity during the said electric discharge machining.