Underwater electrical discharge machining cutting test piece rack and test method

Abstract

The invention belongs to the technical field of underwater electrical discharge machining cutting, and particularly relates to an underwater electrical discharge machining cutting test piece rack and a test method. The underwater electrical discharge machining cutting test piece rack comprises a test rack, an execution mechanism and a test cutting flange. And the execution mechanism and the test cutting flange are positioned and mounted on the test rack. The executing mechanism comprises a cutting executing mechanism and a gear transmission mechanism connected with the remote operation long rod. The cutting executing mechanism comprises an electrode, a positioning sleeve, a pressing spring, a hydraulic oil cylinder and a servo valve. The cutting executing mechanism achieves feeding movement in the cutting process of the whole cutting executing mechanism under joint cooperation of the hydraulic oil cylinder and the servo valve. The electrode and the test cutting flange are respectively connected to two electrodes of an electric spark machining pulse power supply. According to the test piece rack special for machining and cutting the workpiece limiting groove, the technical problem that no supporting equipment for verifying the electric spark machining workpiece limiting groove exists at present is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of underwater electric discharge machining cutting, and particularly relates to an underwater electric discharge machining cutting test piece rack and a test method. BACKGROUND

[0002] The in-core support column of the bottom of the in-core support column of the nuclear power plant pressurized water reactor pressure vessel connects the core bottom plate, the flow distribution plate and the basket bottom plate, and is fixed through the locking nut with the anti-loosening structure at the lower end. When the anti-loosening structure of the locking nut is subjected to long-term nuclear irradiation and water flow impact, the defect position cannot withstand the flow-induced vibration load and thermal load, and fatigue fracture occurs at the anti-loosening position. In addition, the loosening parts produce friction and vibration under the impact of the water flow, further increasing the damage of the support column and affecting the support strength.

[0003] Therefore, the anti-loosening structure of the locking nut of the support column needs to be regularly inspected, and the locking nut with the risk of loosening needs to be disassembled and updated.

[0004] The new anti-loosening cap is in the shape of a bottomed cylinder, and has two side bosses on the side. Before installation, two symmetrical anti-loosening cap limiting grooves need to be processed on the outer side of the locking nut mounting hole pre-installed on the basket bottom plate. The reactor has strong radioactivity after long-term operation, and needs to be shielded in several meters of boron-containing water, so the entire processing needs to be carried out in boron-containing water. In addition, the basket is used to fix the fuel assembly during the operation of the reactor, so the overall strength of the basket is very high, which requires that the force acting on the basket body during any processing process be as small as possible to avoid affecting the mechanical properties of the basket cylinder structure. After comparison, the electrical discharge machining (EDM) method has the advantages of no contact between the electrode material and the workpiece during processing, short discharge process time, energy-intensive, small heat diffusion range, small heat impact on the workpiece, small processing debris particles, easy dust collection and recycling, etc. It is the most suitable for processing the limiting groove. Because the size of the current and the electrode material will affect the processing effect and quality, and due to the unique nature of the nuclear, the operator needs to work remotely. In order to ensure the processing quality, reasonable process parameters need to be determined, so test and verification work needs to be completed before use. Therefore, a new experimental device needs to be invented according to the application situation to serve as a verification support equipment. SUMMARY

[0005] Therefore, the application provides an underwater electric discharge machining cutting test piece rack and a test method, which designs a test piece rack specially used for machining and cutting of the workpiece limiting groove, to solve the technical problem that there is no support equipment for verifying the electrical discharge machining workpiece limiting groove.

[0006] The first aspect of the present application provides a test bench for underwater electro-discharge machining cutting, which comprises a test frame, an actuating mechanism and a test cutting flange. The actuating mechanism and the test cutting flange are positioned and installed on the test frame. The actuating mechanism comprises a cutting actuating mechanism and a gear transmission mechanism connected with a remote operation long rod. The cutting actuating mechanism is used to perform rotation positioning and machining actions under the driving of the gear transmission mechanism. The gear transmission mechanism is used to assist the cutting actuating mechanism to rotate to an accurate cutting station under the driving of the remote operation long rod. The cutting actuating mechanism comprises an electrode, a positioning sleeve, a compression spring, a hydraulic cylinder and a servo valve. The electrode is a terminal execution element of the cutting actuating mechanism, and the positioning sleeve is used for positioning a workpiece to be machined. The compression spring is used for compressing the workpiece to be machined. The cutting actuating mechanism realizes feeding motion in the whole cutting process of the cutting actuating mechanism under the cooperation of the hydraulic cylinder and the servo valve. The electrode and the test cutting flange are used to connect to two poles of a pulse power supply for electric spark machining respectively.

[0007] In one specific embodiment of the present application, the actuating mechanism further comprises a positioning hoisting mechanism. The positioning hoisting mechanism is installed on the gear transmission mechanism and is used for hoisting and positioning.

[0008] In one specific embodiment of the present application, the test frame comprises a top plate, a bottom plate, a support column, a fixed adapter flange and a support adapter seat. The bottom plate supports the top plate through a plurality of support columns. The fixed adapter flange is connected or detached with a mounting hole in the middle of the top plate through lug structures on both sides. The test cutting flange is installed inside the fixed adapter flange. When the test cutting flange needs to be installed, the fixed adapter flange is rotated and detached from the mounting hole in the middle of the top plate. After the installation of the test cutting flange is completed, the fixed adapter flange is reinstalled on the top plate to realize the replacement of the test cutting flange. The support adapter seat is installed on the bottom plate and is used for positioning and installing the actuating mechanism during the test.

[0009] In one specific embodiment of the present application, the number of the plurality of support columns is four.

[0010] In one specific embodiment of the present application, the gear transmission mechanism comprises a gear box, a bevel gear and a gear shaft installed in the gear box, and a shaft coupling and an adapter shaft connected with the gear shaft.

[0011] In one specific embodiment of the present application, the number of the test cutting flanges is multiple.

[0012] The second aspect of the present application provides a test method for underwater electro-discharge machining cutting, which comprises steps S10 to S40.

[0013] In step S10, the cutting actuating mechanism is rotated and positioned under the driving of the gear transmission mechanism, so as to ensure that the electrode is aligned with the cutting station.

[0014] Step S20, the electrode realizes the feeding movement upward under the cooperation of the hydraulic cylinder and the servo valve.

[0015] Step S30, the pulse voltage is applied between the electrode and the test cutting flange connected to the two poles of the electric spark machining pulse power source, the materials on the surface of the test cutting flange and the electrode are locally melted, and the cutting of the workpiece limiting groove of the workpiece being machined is carried out in cooperation with the feeding movement.

[0016] Step S40, if the machining of the workpiece limiting groove of the workpiece being machined fails to be machined in place, the electrode is replaced, and step S30 is executed again until the machining requirement is reached.

[0017] In an embodiment of the present application, step S40 comprises step S41.

[0018] Step S41, if the machining of the workpiece limiting groove of the workpiece being machined fails to be machined in place, the data is recorded, the electrode is replaced, and step S30 is executed again until the machining requirement is reached.

[0019] In an embodiment of the present application, the underwater electric discharge machining cutting test method further comprises step S50.

[0020] Step S50, if the machining of the workpiece limiting groove of the workpiece being machined is in place, the data is recorded and analyzed to determine the accurate process parameters.

[0021] In an embodiment of the present application, before step S10, the underwater electric discharge machining cutting test method further comprises step S1 and step S2.

[0022] Step S1, the executing mechanism and the test cutting flange are positioned and installed on the test rack.

[0023] Step S2, the entire underwater electric discharge machining cutting test piece rack is hoisted to the water for experimental operation by using the positioning hoisting mechanism.

[0024] The beneficial effects of the technical scheme of the present application are that by designing an underwater electric discharge machining cutting test piece rack as a supporting device for verifying the workpiece limiting groove of the electric spark machining, the safety and machining precision in actual use are ensured. In addition, the test data obtained by using the underwater electric discharge machining cutting test method provides effective reference data for the electric spark machining means in the deep water area of the reactor in the future. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The structure schematic diagram of the underwater electric discharge machining cutting test piece rack provided by an embodiment of the present application is shown.

[0026] Figure 2Fig. 1 is a structural schematic diagram of a test machine frame in a test piece rack for underwater electric discharge machining cutting according to an embodiment of the present application.

[0027] Figure 3 Fig. 2 is a structural schematic diagram of an actuator in a test piece rack for underwater electric discharge machining cutting according to an embodiment of the present application.

[0028] Figure 4 Fig. 3 is a structural schematic diagram of a top plate in a test piece rack for underwater electric discharge machining cutting according to an embodiment of the present application.

[0029] Figure 5 Fig. 4 is a structural schematic diagram of a fixed adapter flange in a test piece rack for underwater electric discharge machining cutting according to an embodiment of the present application.

[0030] Figure 6 Fig. 5 is a structural schematic diagram of a test cutting flange in a test piece rack for underwater electric discharge machining cutting according to an embodiment of the present application.

[0031] Figure 7 Fig. 6 is a flowchart of a test method for underwater electric discharge machining cutting according to an embodiment of the present application.

[0032] Figure 8 Fig. 7 is a flowchart of a test method for underwater electric discharge machining cutting according to another embodiment of the present application.

[0033] In the figure, test machine frame 1, top plate 11, bottom plate 12, support column 13, fixed adapter flange 14, support adapter seat 15; actuator 2, cutting actuator 21, electrode 211, positioning sleeve 212, compression spring 213, hydraulic cylinder 214, servo valve 215, gear transmission mechanism 22, gear box 221, bevel gear 222, gear shaft 223, coupling 224, adapter shaft 225, positioning hoisting mechanism 23; test cutting flange 3; remote operation long lever 4. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0035] At least one embodiment of the present application provides a test piece rack for underwater electric discharge machining cutting, which refers to Figures 1 to 6The underwater electric discharge machining cutting test piece rack comprises a test rack 1, an actuating mechanism 2 and a test cutting flange 3. The actuating mechanism 2 and the test cutting flange 3 are positioned and installed on the test rack 1. The actuating mechanism 2 comprises a cutting actuating mechanism 21 and a gear transmission mechanism 22 connected with a remote operation long lever 4. The cutting actuating mechanism 21 is used to perform rotating positioning and machining action under the driving of the gear transmission mechanism 22. The gear transmission mechanism 22 is used to assist the cutting actuating mechanism 21 to rotate to an accurate cutting position under the driving of the remote operation long lever 4. The cutting actuating mechanism 21 comprises an electrode 211, a positioning sleeve 212, a pressing spring 213, a hydraulic cylinder 214 and a servo valve 215. The electrode 211 is a terminal execution element of the cutting actuating mechanism 21, and the positioning sleeve 212 is used for positioning a machined workpiece. The pressing spring 213 is used for pressing the machined workpiece. The cutting actuating mechanism 21 realizes the feeding motion of the whole cutting process under the cooperation of the hydraulic cylinder 214 and the servo valve 215. The electrode 211 and the test cutting flange 3 are used for connecting to two poles of a pulse power source of electric spark machining respectively.

[0036] It should be noted that the test rack 1 is an important component supported and fixed by the experimental device. The actuating mechanism 2 can be an EDM actuating mechanism. The actuating mechanism 2 is a core component of the device. The test cutting flange 3, as a cutting object, is installed and fixed in the fixed adapter flange 14 on the test rack 1. The test cutting flange 3 can also be called a to-be-cut flange. The gear transmission mechanism 22 can assist the electrode 211 to rotate to an accurate cutting position under the driving of the remote operation long lever 4.

[0037] According to the technical scheme provided in the embodiments of the present application, by designing an underwater electric discharge machining cutting test piece rack, as a supporting device for verifying the electric spark machining (also known as EDM machining) workpiece limiting groove, the safety and machining precision in actual use are ensured.

[0038] In at least one embodiment of the present application, referring to Figure 2 The test rack 1 comprises a top plate 11, a bottom plate 12, a support column 13, a fixed adapter flange 14 and a support adapter seat 15. The bottom plate 12 supports the top plate 11 to a certain height through a plurality of support columns 13. The fixed adapter flange 14 is connected or detached with the mounting hole in the middle of the top plate 11 through the lug structures on both sides. The test cutting flange 3 is installed in the fixed adapter flange 14. When the test cutting flange 3 needs to be installed, the fixed adapter flange 14 is rotated and detached from the mounting hole in the middle of the top plate 11. After the installation of the test cutting flange 3 is completed, the fixed adapter flange 14 is reinstalled on the top plate 11, so that the test cutting flange 3 is replaced. The support adapter seat 15 is installed on the bottom plate 12 and used for positioning and installing the actuating mechanism 2 during the test.

[0039] It should be noted that the bottom plate 12 is the mounting plate of the entire test rack 1. The fixed adapter flange 14 can be quickly connected or disconnected with the mounting hole in the middle of the top plate 11 through the lug structure on both sides.

[0040] In at least one embodiment of the present application, the number of the plurality of struts 13 is four.

[0041] In at least one embodiment of the present application, referring to Figure 3 The actuator 2 further comprises a positioning and lifting mechanism 23. The positioning and lifting mechanism 23 is installed on the gear transmission mechanism 22 and is used for lifting and positioning. In this way, the positioning and lifting mechanism 23 can be used for lifting and positioning in subsequent actual use.

[0042] In at least one embodiment of the present application, referring to Figure 3 The gear transmission mechanism 22 comprises a gear box 221, a bevel gear 222 and a gear shaft 223 installed in the gear box 221, and a shaft coupling 224 and an adapter shaft 225 connected with the gear shaft 223.

[0043] In at least one embodiment of the present application, the number of the test cutting flanges 3 is multiple. In this way, by providing multiple test cutting flanges 3, the multiple test cutting flanges 3 can be used for multiple test tests.

[0044] At least one embodiment of the present application also provides an underwater electric discharge machining cutting test method, which is executed by the underwater electric discharge machining cutting test bench in the above-mentioned embodiments. The test environment of the underwater electric discharge machining cutting test method can be in boron-containing deionized water below 10 meters.

[0045] Referring to Figure 7 The underwater electric discharge machining cutting test method comprises the following steps S10 to S40.

[0046] Step S10, the cutting actuator 21 is rotated and positioned under the driving of the gear transmission mechanism 22, ensuring that the electrode 211 is aligned with the cutting station.

[0047] For example, the gear transmission mechanism 22 assists the cutting actuator 21 to rotate and position, ensuring that the electrode 211 is aligned with the machining position. Step S10 is the step of rotating and positioning the actuator 2 in Figure 8 .

[0048] Step S20, the electrode 211 realizes upward feeding motion under the cooperation of the hydraulic oil cylinder 214 and the servo valve 215.

[0049] For example, after the electrode 211 is aligned with the cutting station, the electrode 211 is driven by the hydraulic oil cylinder 214 to make upward feeding motion. Step S20 is the step of Figure 8The step of feeding the actuator 2 upward.

[0050] Step S30: Apply a pulse voltage between the electrode 211 and the test cutting flange 3, which are respectively connected to the two poles of the EDM pulse power supply. The materials on the surface of the test cutting flange 3 and the surface of the electrode 211 are partially melted, and the workpiece limit groove of the workpiece being processed is cut in conjunction with the feed movement.

[0051] For example, the EDM pulse power supply is powered on, and a pulse voltage is applied between the electrode 211 and the test cutting flange 3. The materials on the surface of the test cutting flange 3 and the surface of the electrode 211 are partially melted, and the limit groove is cut in conjunction with the feed motion, so that the workpiece limit groove processing can be realized. Step S30 is Figure 8 The middle electrode 211 is energized for cutting.

[0052] It should be noted that the workpiece limiting groove can be a locking cap limiting groove.

[0053] Step S40: If the workpiece limiting groove of the workpiece being processed is not processed in place, the electrode 211 is replaced multiple times and step S30 is executed again until the processing requirement is met.

[0054] It should be noted that the processing in step S30 does not allow the workpiece limiting groove to be formed in one go. If it cannot be formed in one go, the electrode 211 is replaced multiple times until the processing requirements are met.

[0055] In some embodiments, the machining accuracy, quality, and machining time achieved by a single electrode 211 under different conditions can be tested according to pre-designed feed rates and pulse currents. Testing can include testing the machining quality of cut grooves under different pulse currents, different electrode materials, and different feed rates; testing the machining depth and machining time of a single electrode; and testing the number of cuts and the number of electrode replacements required during the entire machining process.

[0056] According to the technical solution provided in the embodiment of the present application, the test data obtained by using the above-mentioned underwater electrical discharge machining cutting test method provides effective reference data for future electrical discharge machining methods in deep water areas within reactors.

[0057] In at least one embodiment of the present application, step S40 includes step S41.

[0058] Step S41: If the workpiece limiting groove of the workpiece being processed is not processed in place, record the data, replace the electrode, and execute step S30 again until the processing requirements are met.

[0059] For example, it can be determined whether the processing is in place first. If the processing is not in place, the data is recorded and the electrode is replaced, and the step of energizing the electrode and cutting in step S30 is performed again.

[0060] In at least one embodiment of the present application, the underwater electric discharge machining cutting test method further comprises step S50.

[0061] Step S50, if the machining of the workpiece limiting groove of the machined workpiece is in place, record and analyze the data to determine the accurate process parameters.

[0062] For example, it can be determined whether the machining is in place, and if the machining is in place (i.e., meets the machining requirements), record and analyze the data to determine the accurate process parameters.

[0063] It should be noted that the data is recorded, analyzed, and reasonable electrode material, pulse current parameters, feed speed parameters, replacement frequency, and machining time are found.

[0064] Through the above specific operation, a reasonable machining process is found to ensure the machining quality and precision of the workpiece limiting groove.

[0065] In at least one embodiment of the present application, the underwater electric discharge machining cutting test method further comprises steps S1 and S2.

[0066] Step S1, position and install the actuator 2 and the test cutting flange 3 on the test rack 1.

[0067] Specifically, first, position and install the actuator 2 on the test rack 1 (i.e., the step of positioning the actuator 2 in the above embodiment), and then position and install the test cutting flange 3 (also referred to as the cutting test flange) on the test rack 1 (i.e., the step of positioning the cutting test flange in the above embodiment). Figure 8 Figure 8

[0068] For example, the actuator 2 is positioned and installed on the test rack 1 and locked. The test cutting flange 3 simulates the plate outside the pre-installed locking nut mounting hole of the basket bottom plate, and is installed in the fixed adapter flange 14 by bolts, and is locked together with the top plate 11 on the rack by means of the lug structure on both sides of the fixed adapter flange 14. The relative position of the actuator 2 and the test cutting flange 3 is the same as the actual situation underwater in the reactor.

[0069] Step S2, use the positioning and hoisting mechanism 23 to hoist the entire underwater electric discharge machining cutting test piece rack to the water for experimental operation.

[0070] It should be noted that the combination of the technical features in the embodiments of the present application is not limited to the combination of the technical features in the embodiments of the present application or the combination of the technical features in the embodiments of the present application. All technical features described in the present application can be freely combined or combined in any way, unless contradictory.

[0071] ​​As used in this application and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The terms "comprises" and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0072] The preferred embodiments of the application are described above in detail. The application is not limited to the embodiments described above, but can be modified in various ways which will be suggested to a skilled person by the content of the present description. Accordingly, the application is not limited to the above-described embodiments, but can be modified in various ways without departing from the spirit and scope of the application.

Claims

1. An underwater electrical discharge machining cutting test piece stand, characterized in that: It includes a test frame, an actuator and a test cutting flange, wherein the actuator and the test cutting flange are positioned and installed on the test frame. The actuator includes a cutting actuator and a gear transmission mechanism connected to a remote operating long rod. The cutting actuator is used to perform rotational positioning and processing actions under the drive of the gear transmission mechanism. The gear transmission mechanism is used to assist the cutting actuator in rotating to an accurate cutting position under the drive of the remote operating long rod. The cutting actuator includes an electrode, a positioning sleeve, a clamping spring, a hydraulic cylinder and a servo valve. The electrode is the end actuator of the cutting actuator; the positioning sleeve is used to position the workpiece to be processed; the clamping spring is used to clamp the workpiece to be processed; the cutting actuator realizes the feed movement of the cutting actuator during the cutting process under the joint cooperation of the hydraulic cylinder and the servo valve; the electrode and the test cutting flange are used to be respectively connected to the two poles of the electric spark machining pulse power supply.

2. The underwater electrical discharge machining cutting test piece stand according to claim 1, characterized in that: The actuator further comprises a positioning and hoisting mechanism, which is installed on the gear transmission mechanism and is used for hoisting and positioning.

3. The underwater electric discharge machining cutting test piece stand according to claim 1, characterized in that: The test frame includes a top plate, a bottom plate, pillars, a fixed adapter flange and a support adapter seat, and the bottom plate supports the top plate through multiple pillars; the fixed adapter flange is connected or disconnected from the mounting hole in the middle of the top plate through the lug structures on both sides; the support adapter seat is installed on the bottom plate and is used for positioning and installing the actuator during testing; the test cutting flange is installed inside the fixed adapter flange, and when the test cutting flange needs to be installed, the fixed adapter flange is rotated to remove it from the mounting hole in the middle of the top plate. After the test cutting flange is installed, the fixed adapter flange is reinstalled on the top plate to replace the test cutting flange.

4. The underwater electrical discharge machining cutting test piece stand according to claim 3, characterized in that: The number of the plurality of pillars is four.

5. The underwater electrical discharge machining cutting test piece stand according to claim 1, characterized in that: The gear transmission mechanism includes a gear box, a bevel gear and a gear shaft installed in the gear box, and a coupling and a transfer shaft connected to the gear shaft.

6. The underwater electrical discharge machining cutting test piece stand according to any one of claims 1 to 5, characterized in that: There are multiple test cutting flanges.

7. An underwater electrical discharge machining cutting test method, characterized in that: The underwater electrical discharge machining cutting test piece stand according to any one of claims 1 to 6 is used for the test, and the underwater electrical discharge machining cutting test method comprises: Step S10: Rotate and position the cutting actuator under the drive of the gear transmission mechanism to ensure that the electrode is aligned with the cutting station; Step S20: The electrode performs an upward feeding motion under the cooperation of the hydraulic cylinder and the servo valve; Step S30, applying a pulse voltage between the electrode and the test cutting flange, which are respectively connected to two poles of an EDM pulse power supply, so that the material on the surface of the test cutting flange and the surface of the electrode partially melts, and cutting the workpiece limit groove of the workpiece being machined is performed in conjunction with the feed motion; Step S40: If the workpiece limiting groove of the workpiece being processed cannot be processed to the desired position, step S30 is executed again by replacing the electrode until the processing requirement is met.

8. The underwater electrical discharge machining cutting test method according to claim 7, characterized in that: Step S40 includes: Step S41: If the workpiece limiting groove of the workpiece being processed is not processed in place, record the data, replace the electrode, and execute step S30 again until the processing requirements are met.

9. The underwater electrical discharge machining cutting test method according to claim 7, characterized in that: Also includes: Step S50: If the workpiece limiting groove of the workpiece being processed is processed in place, record and analyze the data to determine accurate process parameters.

10. An underwater electrical discharge machining cutting test method according to any one of claims 7 to 9, characterized in that: Before step S10, the underwater electrical discharge machining cutting test method further includes: Step S1, positioning and installing the actuator and the test cutting flange on a test frame; Step S2: Using a positioning and hoisting mechanism, the entire underwater EDM cutting test piece stand is hoisted underwater for experimental operation.

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