A non-uniform-thickness thin-wall electrode for electrospark trepanning and a manufacturing method thereof

Abstract

The present invention discloses a non-uniform thickness thin-walled electrode and method for electrospark trepanning, which belongs to the technical field of discharge machining. The non-uniform thickness thin-walled electrode for electrospark trepanning comprises a thin-walled electrode body, which is a ring-shaped structure with a corner in the inner ring, and the wall thickness of the thin-walled electrode body at the corner is less than the wall thickness of the thin-walled electrode body away from the corner. The inner wall of the thin-walled electrode body gradually expands outward from a position a predetermined distance from the corner to the corner, so that the wall thickness of the thin-walled electrode body gradually becomes thinner from a position a predetermined distance from the corner to the corner. The present invention improves the problem of uneven thin-walled electrode loss during trepanning discharge machining caused by the larger thickness of the corners of ordinary thin-walled electrodes, and reduces the appearance of sharp corners after thin-walled electrode machining.

Description

Technical Field

[0001] The invention belongs to the field of trepanning electric discharge machining, and in particular relates to a non-uniform thickness thin-wall electrode for trepanning electric discharge machining and a manufacturing method thereof. Background Art

[0002] Jacketed EDM technology is a new type of processing technology used to process specific shapes. Its electrodes are generally thin-walled electrodes. Compared with traditional EDM, it has the advantages of good processing quality, high stability and high processing efficiency.

[0003] Electrode loss is an inevitable phenomenon in EDM. During the EDM process, due to the combined effects of electric field force, magnetic force, thermal force, fluid dynamics, electrochemistry, etc. on the electrode during spark discharge, part of the electrode will be eroded.

[0004] When machining non-circular holes with trepanning EDM technology, the thickness of the corners of the thin-walled electrode is inconsistent with that of the side walls of the electrode, and the wall thickness at the corners is relatively larger. Therefore, the electrode corners are less lost during the machining process, which leads to uneven electrode loss. After machining, sharp corners will be formed at the four corners of the electrode. In order to solve this problem, a design method for non-uniform thickness thin-walled electrodes for trepanning EDM is proposed, which can effectively alleviate the phenomenon of uneven thin-walled electrode loss during trepanning EDM. Summary of the Invention

[0005] In order to solve the shortcomings in the existing scenarios, the purpose of the present invention is to provide a non-uniform thickness thin-walled electrode for electrospark trepanning and a manufacturing method thereof. The non-uniform thickness thin-walled electrode can effectively alleviate the problem of uneven electrode loss during trepanning and reduce the appearance of sharp corners at the corners after thin-walled electrode processing.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0007] A non-uniform thickness thin-walled electrode for electrospark trepanning comprises a thin-walled electrode body, which is an annular structure with an inner ring having a corner. The wall thickness of the thin-walled electrode body at the corner is smaller than that of the thin-walled electrode body away from the corner.

[0008] In order to optimize the above scheme, the present invention further takes the following measures:

[0009] The inner wall of the thin-walled electrode body gradually expands outward from a position at a predetermined distance from the corner to the corner, so that the wall thickness of the thin-walled electrode body gradually becomes thinner from the position at a predetermined distance from the corner to the corner.

[0010] The corners are chamfered with smooth transition.

[0011] The thin-walled electrode body includes a normal thickness zone, a thickness transition zone and a corner zone. The corner is set on the inner side of the corner zone. The normal thickness zone and the corner zone are connected by the thickness transition zone. The normal thickness zone is the thickest area of ​​the thin-walled electrode body, and the corner zone is the thinnest area of ​​the thin-walled electrode body. After the thin-walled electrode body is circumferentially sectioned, the connection point between the inner wall of the normal thickness zone and the inner wall of the thickness transition zone is used as the origin, the inner wall of the normal thickness zone is used as the x-axis, and the thickness direction of the normal thickness zone is used as the y-axis. The inner wall change curve of the thickness transition zone is y=k·x, where k is a constant.

[0012] The inner wall of the normal thickness zone transitions smoothly to the inner wall of the thickness transition zone.

[0013] A method for preparing a non-uniform thickness thin-walled electrode for electrospark trepanning, wherein the method comprises the following steps:

[0014] Step 1: Punch a hole in the center of the original blank to form a hole that goes through the top and bottom. Then insert the wire cutting electrode wire into the hole.

[0015] Step 2: Use the wire cutting electrode wire to perform shaping cutting on the inner wall of the electrode according to a specific cutting route. When the wire cutting electrode wire is cutting, the inner wall of the thin-walled electrode body formed gradually expands outward from a position at a predetermined distance from the corner to the corner;

[0016] Step 3: Take out the wire-cut electrode wire from the inner wall of the thin-walled electrode body and install the wire-cut electrode wire on the outside of the original blank;

[0017] Step 4: Shape and cut the outer wall of the electrode according to a specific cutting route to finally obtain a thin-walled electrode body.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention proposes a thin-walled electrode with non-uniform wall thickness, thereby improving the problem of uneven wear of the thin-walled electrode during the trepanning EDM process, which results in a larger thickness at the corners of the conventional thin-walled electrode.

[0020] 2. The present invention reduces the appearance of sharp corners after thin-wall electrode processing through the structure of non-uniform wall thickness, and improves the problem of uneven electrode loss in cladding processing.

[0021] 3. The method of making thin-walled electrodes of unequal wall thickness proposed in the present invention is easy to understand and master. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the non-uniform thickness thin-walled electrode processed by electrospark trepanning of the present invention;

[0023] Figure 2It is a stereoscopic diagram of the invention of the non-uniform thickness thin-walled electrode for electrospark trepanning;

[0024] Figure 3 yes Figure 2 A top view of

[0025] Figure 4 This is a schematic diagram of the corner structure of a common thin-walled electrode;

[0026] Figure 5 This is a schematic diagram of the corner structure of a non-uniform thickness thin-walled electrode;

[0027] Figure 6 This is a detailed wiring diagram of the inner wall of a thin-walled electrode with non-uniform wall thickness;

[0028] Figure 7 This is a schematic diagram of the manufacturing process of thin-walled electrodes with non-uniform wall thickness.

[0029] Figure 8 It is a schematic diagram of the nesting process.

[0030] The figures are marked as: thin-walled electrode body 1, normal thickness zone 11, thickness transition zone 12, corner zone 13, corner 2, original blank 3, wire-cut electrode wire 4, inner electrode wire routing 5, outer electrode wire routing 6, electrode before trepanning 7, electrode after trepanning 71, sharp corner remaining at electrode corner after trepanning 72, processing area of ​​electrode 73, trepanning blank before trepanning 8, trepanning blank after trepanning 81, and trepanning part 82. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0032] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. cited in the invention are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments:

[0034] like Figure 1 Figure 1 shows a design method for a non-uniform-thickness thin-walled electrode for EDM machining. The thin-walled electrode has a wall thickness of a. The design concept uses a predetermined curve as the path, starting at a distance L from corner 2, to gradually expand the electrode's inner wall outward, reducing the wall thickness at corner 2. To smoothly connect the curve at both ends of corner 2, an arc with a radius of R is designed, tangent to the curve at both ends.

[0035] Because of the problem of electrode wire cutting production, the radius of the arc should be greater than the radius of the electrode wire d / 2, and considering that the wall thickness at the corner after the change should not be much different from the wall thickness of the ordinary electrode, the radius of the arc should be less than ba. Therefore, the radius of the arc should be selected within the range of (d / 2, ba). The specific selection should be determined based on experiments.

[0036] like Figure 2-3 As shown in the figure, a non-uniform thickness thin-walled electrode is used for processing a square hole as an example. The outer dimensions of the electrode are approximately 20mm×30mm, and the wall thickness is 0.5mm. The wall thickness gradually decreases from the middle part of the electrode, which is about 20mm away from the corner, to the corners at both ends, so that the wall thickness at the corners reaches 0.5mm.

[0037] like Figure 4 and 8 As shown by Figure 4 It can be seen that the thickness of the corners of the thin-walled electrode processed by ordinary cladding is significantly greater than the thickness of the two sides of the electrode, so Figure 8 The thin-walled electrode produced by the jacketing process will show uneven wear after processing, especially sharp corners will appear at the corners.

[0038] In order to alleviate the above problems, the present invention makes the wall thickness of the thin-walled electrode gradually expand outward from a certain distance at both ends of the electrode corner toward the corner, that is, the wall thickness gradually decreases, thereby obtaining a non-uniform wall thickness thin-walled electrode.

[0039] like Figure 5 As shown, the difference between the non-equal wall thickness thin-walled electrode proposed by the present invention and the ordinary thin-walled electrode mainly lies in the direction of the inner wall of the electrode. The direction of the inner wall of the ordinary thin-walled electrode is the same as the direction of the outer wall, and the wall thickness at the corner is larger. The direction of the inner wall of the non-equal wall thickness thin-walled electrode is different from the direction of the outer wall. The outer wall of the electrode is related to the shape of the processing hole, so it cannot be changed. Therefore, the non-equal wall thickness thin-walled electrode is obtained by changing the direction of the inner wall, thereby reducing the wall thickness at the corner, thereby reducing the appearance of sharp corners after electrode processing, and alleviating the problem of uneven electrode processing loss.

[0040] like Figure 6 As shown, the inner wall of the thin-walled electrode gradually expands outward along the inner wall variation curve starting approximately 20 mm from the corner. The curve equation of this variation curve is y = k·x, with a slope k of 0.009, and changes slowly. Because the electrode manufacturing process must be considered, wire cutting is used for cutting. To facilitate the routing of the wire cutting electrode wire 4, namely the molybdenum wire, a fillet with a radius greater than 0.1 mm is designed at the corner for transition.

[0041] like Figure 7 The figure shows the production process of thin-walled electrodes with non-uniform wall thickness, which is produced by wire cutting. The specific steps are as follows:

[0042] A 4 mm through hole is drilled in the middle of the original blank 3 used for making the electrode to obtain a perforated blank.

[0043] A wire cutting electrode wire 4 is passed through the through hole on a wire cutting machine.

[0044] The wire cutting machine is operated to cut along the inner electrode wire route 5 when cutting the inner wall, to obtain the blank after the inner wall is cut out.

[0045] Then the electrode wire of the wire cutting machine passes through the inner wall and cuts from the outside of the blank after the inner wall is cut.

[0046] The wire cutting machine is operated to perform cutting according to the outer electrode wire route 6 when cutting the outer wall, thereby obtaining a cut thin-walled electrode body 1 .

[0047] Using non-uniform thickness thin-walled electrodes Figure 8 The process shown processes the blank to obtain the square hole produced by the nesting and the waste produced by the nesting.

[0048] Using thin-walled electrodes with non-uniform wall thickness for trepanning of square holes results in more uniform electrode wear after machining, and significantly improved sharp corner problems at electrode corners.

[0049] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0050] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A non-uniform thickness thin-walled electrode for electrospark trepanning machining, comprising a thin-walled electrode body (1), wherein the thin-walled electrode body (1) is a ring-shaped structure with an inner ring having a corner (2), and is characterized in that: The wall thickness of the thin-walled electrode body (1) at the corner (2) is smaller than the wall thickness of the thin-walled electrode body (1) away from the corner (2).

2. The non-uniform thickness thin-walled electrode for electrospark trepanning according to claim 1, characterized in that: The inner wall of the thin-walled electrode body (1) gradually expands outward from a position at a predetermined distance from the corner (2) to the corner (2), so that the wall thickness of the thin-walled electrode body (1) gradually becomes thinner from the position at a predetermined distance from the corner (2) to the corner (2).

3. The non-uniform thickness thin-walled electrode for electrospark trepanning according to claim 1, characterized in that: The corner (2) is provided with a chamfer with a smooth transition.

4. The non-uniform thickness thin-walled electrode for electrospark trepanning according to claim 1, characterized in that: The thin-walled electrode body (1) comprises a normal thickness region (11), a thickness transition region (12) and a corner region (13); the corner (2) is arranged on the inner side of the corner region (13); the normal thickness region (11) and the corner region (13) are connected via the thickness transition region (12); the normal thickness region (11) is the thickest region of the thin-walled electrode body (1); and the corner region (13) is the thinnest region of the thin-walled electrode body (1). After the thin-walled electrode body (1) is circumferentially sectioned, the connection point between the inner wall of the normal thickness region (11) and the inner wall of the thickness transition region (12) is taken as the origin, the inner wall of the normal thickness region (11) is taken as the x-axis, and the thickness direction of the normal thickness region (11) is taken as the y-axis. The inner wall variation curve of the thickness transition region (12) is y=k·x, where k is a constant.

5. The non-uniform thickness thin-walled electrode for electrospark trepanning according to claim 4, characterized in that: The inner wall of the normal thickness zone (11) and the inner wall of the thickness transition zone (12) transition smoothly.

6. A method for preparing a non-uniform thickness thin-walled electrode for electrospark trepanning, characterized in that: The method for manufacturing the non-uniform thickness thin-walled electrode according to claim 1 comprises the following steps: Step 1: Punch a hole in the center of the original blank (3) to form a hole that goes through the top and bottom, and then insert the wire cutting electrode wire (4) into the hole. Step 2: Using a wire cutting electrode wire (4) to perform shaping cutting on the inner wall of the electrode according to a specific cutting route, when the wire cutting electrode wire (4) cuts, the inner wall of the formed thin-walled electrode body (1) gradually expands outward from a position at a predetermined distance from the corner (2) to the corner (2); Step 3: Take out the wire-cut electrode wire (4) from the inner wall of the thin-walled electrode body (1), and install the wire-cut electrode wire (4) outside the original blank (3); Step 4: forming and cutting the outer wall of the electrode according to a specific cutting route, and finally obtaining a thin-walled electrode body (1).

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