An efficient combined machining method for electric discharge material extraction

Abstract

The present invention discloses a high-efficiency combined machining method for electric discharge material extraction. The tubular hollow electrode is used to drill holes in a workpiece at high speed, providing preparation for subsequent high-efficiency machining using a square tubular electrode. The square tubular electrode is a sleeve electrode with a certain wall thickness, which erodes the materials around the part where material extraction is required, leaving a groove with the same shape as the cross-section of the square tubular electrode on the workpiece after machining. The frame-shaped electrode can be annular, rectangular or L-shaped, which erodes the materials on the bottom surface of the square cavity. After machining with the frame-shaped electrode, the material core for material extraction will be separated from the workpiece matrix as a whole. In the process of machining the cavity by this high-efficiency material extraction method, only the materials around the cavity and on the bottom surface need to be eroded, greatly reducing the amount of eroded materials, lowering the machining cost and shortening the machining cycle.

Description

Technical Field

[0001] The present invention belongs to the technical field, and particularly relates to a high-efficiency combined machining method for electric discharge machining of material removal. Background Art

[0002] In the field of aerospace, due to requirements for strength and weight, a large number of integral structural parts made of difficult-to-machine materials are adopted, such as integral turbine disks and casings of aeroengines. From the blank to the part, the material removal amount of these parts exceeds 80%. Due to the difficult-to-machine characteristics of their materials, there have always been problems of long machining cycles and high tool costs when using traditional CNC milling machining technology. An integral structural part often requires several months of machining, and the cost of imported tools is often hundreds of thousands of yuan. Summary of the Invention

[0003] The purpose of the present invention is to provide a high-efficiency combined machining method for electric discharge machining of material removal to solve the problems of large allowance removal of parts made of difficult-to-machine materials, core removal of cavity parts, and material removal of deep cavities.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A high-efficiency combined machining method for electric discharge machining of material removal, and the specific steps are as follows:

[0005] Step 1: First, clamp a tubular electrode on an electric discharge machining device and supply a working medium to the tubular electrode.

[0006] Step 2: Perform high-speed small-hole electric discharge machining with a fixed depth on the part where material removal is required, and drill holes along the edge of the pre-machined cavity on the upper surface of the workpiece. This step can enhance the exchange efficiency of the working medium between the internal machining area and the external non-machined area of the workpiece during the subsequent machining process, quickly take away the erosion products in the machining area, and maintain the discharge stability of the machining area.

[0007] Step 3: Replace it with a square cylindrical sleeve-shaped electrode, align the lower surface of the electrode with the small holes arranged on the upper surface of the workpiece to form the cavity edge trajectory, and perform high-efficiency electric discharge machining with a fixed depth on the part where material removal is required by flushing liquid in the square cylindrical sleeve-shaped electrode. During the machining process, cooperate with the tool lifting movement. After machining to a certain depth, lift the square cylindrical sleeve-shaped electrode to machine a rectangular groove on the workpiece.

[0008] Step 4:

[0009] S1. Replace it with a frame-shaped electrode, connect the reserved pipe orifice on the frame-shaped electrode to the working medium, then extend the bottom edge of the frame-shaped electrode into the bottom of the square cavity through one groove, and the two sides of the side of the frame-shaped electrode enter both sides of the machined groove, and then perform discharge machining on the bottom of the square cavity.

[0010] S2. After machining in the horizontal direction for a period of time, use the fixed block to fix the position of the core that is about to fall off until the entire core for core extraction is separated from the workpiece matrix, then take out the core material to complete the machining of the blind square cavity.

[0011] Preferably, the tubular electrode is a hollow tube, and the inside of the tube is used to pass the working medium. Its length is greater than the depth of the cavity, and the electrode can rotate during machining.

[0012] Preferably, the square tubular sleeve-shaped electrode has a certain wall thickness, and the wall thickness is in the range of 0.5 mm - 20 mm. There is a channel for passing the working medium inside the electrode wall. The diameter of the channel is smaller than the wall thickness, and the diameter of the channel is in the range of 0.1 mm - 18 mm, and the number of channels is at least one.

[0013] Among any of the above solutions, preferably, the wall thickness of the tubular electrode is 0.5 mm.

[0014] Among any of the above solutions, preferably, the wall thickness of the tubular electrode is 5 mm.

[0015] Among any of the above solutions, preferably, the wall thickness of the tubular electrode is 10 mm.

[0016] Among any of the above solutions, preferably, the wall thickness of the tubular electrode is 20 mm.

[0017] Among any of the above solutions, preferably, the diameter of the channel is Φ0.1 mm.

[0018] Among any of the above solutions, preferably, the diameter of the channel is Φ5 mm.

[0019] Among any of the above solutions, preferably, the diameter of the channel is Φ10 mm.

[0020] Among any of the above solutions, preferably, the diameter of the channel is Φ18 mm.

[0021] Preferably, the hollow inner cavity of the square tubular sleeve-shaped electrode passes the working medium, and its cross-sectional shape is any rectangle, which is determined according to the shape of the cavity to be machined.

[0022] Preferably, the frame-shaped electrode is a hollow electrode tube. The diameter of the electrode tube is in the range of Φ1.0 mm - 20 mm. One end of the frame-shaped electrode is open, and the other end is closed. The working medium can be passed through. The outer diameter of the electrode tube is less than or equal to the wall thickness of the sleeve-shaped electrode. There are small holes for passing the working medium on the tube wall, and the diameter of the holes is in the range of Φ0.3 mm - 15 mm.

[0023] Among any of the above solutions, preferably, the diameter of the electrode tube is Φ1.0 mm.

[0024] Among any of the above solutions, preferably, the diameter of the electrode tube is Φ10 mm.

[0025] Preferably, in any of the above solutions, the diameter of the electrode tube is Φ20 mm.

[0026] Preferably, in any of the above solutions, the diameter of the hole is Φ0.3 mm.

[0027] Preferably, in any of the above solutions, the diameter of the hole is Φ0.15 mm.

[0028] Preferably, the materials of the tubular electrode, the square cylindrical sleeve-shaped electrode, and the frame-shaped electrode are any conductive materials.

[0029] Preferably, the working medium is one or a combination of several of water, oil, working fluid, and gas.

[0030] Preferably, the pressure of the working medium is 0.01 Mpa - 9 Mpa.

[0031] Preferably, in any of the above solutions, the pressure of the working medium is 0.01 Mpa.

[0032] Preferably, in any of the above solutions, the pressure of the working medium is 4 Mpa.

[0033] Preferably, in any of the above solutions, the pressure of the working medium is 9 Mpa.

[0034] Preferably, the basic material of the workpiece to be processed can be a conductive metal and / or a conductive alloy material.

[0035] The beneficial effects are as follows: The present invention greatly improves the working medium exchange efficiency between the machining area and the non-machining area, thereby improving the state of inter-electrode deionization, enhancing the stability of electrical discharge machining, reducing electrode wear, shortening the machining cycle. At the same time, this method is simple to implement, energy-saving, low-cost, increases the maximum machinable depth of the cavity, and is especially suitable for large allowance removal of parts made of difficult-to-machine materials, core removal of cavity parts, and removal of deep cavity materials. Therefore, most of the machining allowance of the overall component can be removed by the fastest method, which can greatly shorten the machining cycle and save the tool usage cost. In addition, for die cavities made of difficult-to-machine materials and some deep cavities, if a part of the material that originally needed to be removed by electrical discharge machining can be quickly removed, it can also greatly improve the machining efficiency of the parts and reduce the production cost, which has important significance for production practice. Description of the Drawings

[0036] Figure 1 is a schematic diagram of the machining process of the present invention;

[0037] Figure 2 is a schematic diagram of the machining state of the present invention.

[0038] In the figure: 1, workpiece; 2, tubular electrode; 3, square cylindrical sleeve electrode; 4, 5, frame-shaped electrode; 6, fixing block; 7, core material. Specific implementation manner

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] The present invention provides a high-efficiency electric discharge machining method for combined material extraction as shown in the figure, and the specific steps are as follows:

[0041] Step 1: First, clamp the tubular electrode on the electric discharge machining equipment and supply the working medium to the tubular electrode.

[0042] Step 2: Perform high-speed small-hole electric discharge machining with a fixed depth on the part that needs to extract material. Drill holes along the edge of the pre-machined cavity on the upper surface of the workpiece. This step can enhance the exchange efficiency of the working medium between the internal machining area and the external non-machined area of the workpiece during the subsequent machining process, quickly take away the erosion products in the working area, and maintain the discharge stability of the machining area.

[0043] Step 3: Replace with the square cylindrical sleeve electrode, align the lower surface of the square cylindrical sleeve electrode with the small holes arranged along the edge of the cavity, and perform high-efficiency electric discharge machining with a fixed depth on the part that needs to extract material by flushing liquid inside the square cylindrical sleeve electrode. During the machining process, cooperate with the tool lifting movement. After machining to a certain depth, lift the square cylindrical sleeve electrode 3 to machine a rectangular groove on the workpiece.

[0044] Step 4:

[0045] S1. Replace with the frame-shaped electrode, connect the reserved pipe orifice on the frame-shaped electrode to the working medium, and then extend the bottom edge of the frame-shaped electrode into the bottom of the square cavity through one end groove. The two sides of the side of the frame-shaped electrode enter both sides of the machined groove, and then perform electric discharge machining on the bottom of the square cavity.

[0046] S2. After machining in the horizontal direction for a period of time, use the fixing block to fix the position of the core material that is about to fall off.

[0047] Here, the fixing block can be a magnetic block and / or a metal block. When the machining has magnetism, the magnetic block can be directly used for adsorption and fixation to prevent it from pressing on the frame-shaped electrode and causing a short circuit after falling off.

[0048] If the processing material has no magnetism, apply 502 glue to the bottom surface of the metal block, and then bond the metal block to the upper surfaces of the core and the workpiece matrix. Continue the processing until the entire core of the material being removed is separated from the workpiece matrix, and then take out the core material to complete the processing of the blind square cavity.

[0049] Specifically, the tubular electrode is a hollow tube, and its interior is used to conduct the working medium. Its length is greater than the depth of the cavity, and the electrode can rotate during the processing.

[0050] Specifically, the square tubular sleeve-shaped electrode has a certain wall thickness within the range of 10 mm. There is a channel for conducting the working medium inside the electrode wall. The diameter of the channel is smaller than the wall thickness and within the range of Φ9 mm, and the number of channels is at least one.

[0051] Specifically, the hollow inner cavity of the square tubular sleeve-shaped electrode conducts the working medium, and its cross-sectional shape is an arbitrary rectangle, which is determined according to the shape of the cavity to be processed.

[0052] Specifically, the frame-shaped electrode is a hollow electrode tube with a diameter within the range of Φ10 mm. One end of the electrode tube is open, and the other end is closed. The working medium can be introduced. The outer diameter of the electrode tube is less than or equal to the wall thickness of the sleeve-shaped electrode, and there are small holes with a diameter of Φ8 mm on the tube wall for conducting the working medium.

[0053] Specifically, the materials of the tubular electrode, the tubular sleeve-shaped electrode, and the frame-shaped electrode are pure copper.

[0054] Specifically, the working medium is deionized water.

[0055] Specifically, the pressure of the working medium is 5 Mpa.

[0056] Specifically, the basic material of the workpiece to be processed is a conductive metal material.

[0057] Working principle: The length, width, and height of the workpiece are 200 mm, 200 mm, and 100 mm respectively, and the length, width, and height of the processed cavity are 100 mm, 50 mm, and 80 mm respectively. The working medium used is deionized water. First, clamp the tubular electrode 2 onto the electric discharge machining equipment, supply deionized water to the tubular electrode, and at the same time rotate the electrode to drill holes on the upper surface of the workpiece 1, as shown in Figure 1 -a. The arrangement trajectory of the holes after processing is shown in the figure. Then remove the tubular electrode 2, and clamp the square tubular sleeve-shaped electrode 3 onto the equipment. There are through holes inside the outer wall of the square tubular sleeve-shaped electrode 3. Connect the holes to the hose for supplying deionized water, and seal the contact surface with glue. After making the preparations, perform tool setting to align the surface of the square tubular sleeve-shaped electrode 3 with the holes processed on the upper surface of the workpiece 1, as shown in Figure 1As shown in -b, machining starts after the working fluid is passed. During the machining process, the electrode lifting movement is coordinated. After machining to a depth of 80 mm, the sleeve electrode 3 is lifted to machine a rectangular groove on the workpiece 1, as Figure 1 shown in -c. After removing the sleeve electrode 3, the workpiece is as Figure 1 shown in -d; Replace it with the frame electrode 5. Connect the reserved pipe orifice on the frame electrode 5 to the hose for passing deionized water and perform tool setting to make the frame electrode 5 perpendicular to the upper surface of the workpiece 1 and move downward along the right narrow side of the rectangular groove, as Figure 1 shown in -e until it touches the bottom of the groove. Then pass deionized water with a liquid pressure of 0.2 Mpa and machine along the direction as Figure 1 shown in -f; When machining reaches about half of the length of the rectangle, as Figure 1 shown in -g and Figure 2 shown, stop machining. Use the fixing block 6 as Figure 1 shown in -f to place it on the groove, so that the fixing block 6 adsorbs to the upper surfaces of both the workpiece 1 and the core 7 simultaneously to prevent the core 7 from tilting when machining approaches the tail and pressing against the electrode to cause a short circuit; After the machining is completed, remove the fixing block 6 and the core 7 in sequence, as Figure 1 shown in -i;

[0058] It greatly improves the working medium exchange efficiency between the machining area and the non-machining area, thereby improving the state of inter-electrode deionization, enhancing the stability of EDM, reducing electrode wear, and shortening the machining cycle. At the same time, this method is simple to implement, energy-saving, and low-cost, and is especially suitable for large allowance removal of parts made of difficult-to-machine materials, core removal of cavity parts, and removal of deep cavity materials.

[0059] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-efficiency combined electrical discharge machining method for material extraction, the specific steps are as follows: Step 1: First, clamp a tubular electrode on the electrical discharge machining equipment and supply the working medium to the tubular electrode. Step 2: Perform high-speed small-hole electrical discharge machining with a fixed depth on the part where material needs to be extracted. Drill holes along the edge of the pre-machined cavity on the upper surface of the workpiece. This step can enhance the exchange efficiency of the working medium between the internal machining area and the external non-machined area of the workpiece during the subsequent machining process, quickly remove the erosion products in the machining area, and maintain the discharge stability of the machining area. Step 3: Replace it with a square tube-shaped sleeve electrode, align the lower surface of the electrode with the small holes arranged along the edge of the cavity on the upper surface of the workpiece, and flush liquid inside the square tube-shaped sleeve electrode. Perform high-efficiency electrical discharge machining with a fixed depth on the part where material needs to be extracted. During the machining process, cooperate with the lifting tool movement. After machining to a certain depth, lift the square tube-shaped sleeve electrode to machine a rectangular groove on the workpiece. Step 4: S1. Replace it with a frame-shaped electrode, connect the reserved pipe orifice on the frame-shaped electrode to the working medium, then extend the bottom edge of the frame-shaped electrode into the bottom of the square cavity through one groove, and the two sides of the side of the frame-shaped electrode enter both sides of the machined groove, and then perform discharge machining on the bottom of the square cavity. S2. After machining horizontally for a period of time, use a magnet or other bonding block to fix the position of the core material that is about to fall off until the entire core material for material extraction is separated from the workpiece matrix, and take out the core material to complete the machining of the blind square cavity.

2. The high-efficiency electric discharge combined machining method for material extraction according to claim 1, wherein: The tubular electrode is a hollow tube, and its internal tube is used to supply the working medium. Its length is greater than the depth of the cavity. During the machining process, the electrode can rotate.

3. A high-efficiency electric discharge combined machining method for material extraction according to claim 1, characterized in that: The tubular electrode has a certain wall thickness, and the wall thickness is in the range of 0.5 mm - 20 mm. There is a channel for supplying the working medium inside the electrode wall. The diameter of the channel is smaller than the wall thickness, and the diameter of the channel is in the range of 0.1 mm - 18 mm. The number of channels is at least one.

4. The high-efficiency spark material extraction combined machining method according to claim 2, characterized in that: The hollow inner cavity of the square tube-shaped sleeve electrode is connected to the working medium, and its cross-sectional shape is an arbitrary rectangle, which is determined according to the shape of the cavity to be machined.

5. A high-efficiency electric discharge combined machining method for material extraction according to claim 1, characterized in that: The frame-shaped electrode is a hollow electrode tube. The diameter of the electrode tube is in the range of Φ1.0 mm - 20 mm. One end of the frame-shaped electrode is open, and the other end is closed, and the working medium can be introduced. The outer diameter of the electrode tube is less than or equal to the wall thickness of the square tube-shaped sleeve electrode. There are small holes for supplying the working medium on the tube wall, and the diameter of the holes is in the range of Φ0.3 mm - 15 mm.

6. A high-efficiency electric discharge combined machining method for material extraction according to claim 1, characterized in that: The materials of the tubular electrode, the square tube-shaped sleeve electrode, and the frame-shaped electrode are any conductive materials.

7. A high-efficiency electric discharge combined machining method for material extraction according to claim 1, characterized in that: The working medium is one or a combination of water, oil, working fluid, and gas.

8. The high-efficiency electric discharge combined machining method for material extraction according to claim 1, wherein: The pressure of the working medium is 0.01 Mpa - 9 Mpa.

9. A high-efficiency electric discharge combined machining method for material extraction according to claim 1, characterized in that: The basic material of the workpiece is a conductive metal and / or a conductive alloy material.

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