A test bench and test method for underwater electrical discharge machining (EDM) cutting of test pieces

Abstract

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. The underwater electric discharge machining cutting test piece rack comprises a test rack, an executing mechanism and a test cutting flange. The executing mechanism and the test cutting flange are positioned and installed on the test rack. The executing mechanism comprises a cutting executing mechanism and a gear transmission mechanism connected with a remote operation long rod. The cutting executing mechanism comprises an electrode, a positioning sleeve, a compression spring, a hydraulic oil cylinder and a servo valve. The cutting executing mechanism realizes the feeding motion in the whole cutting process of the cutting executing mechanism under the cooperation of the hydraulic oil cylinder and the servo valve. The electrode and the test cutting flange are used for being connected to two poles of an electric spark machining pulse power source respectively. The application designs a test piece rack specially used for machining and cutting of a workpiece limiting groove, so as to solve the technical problem that there is no supporting equipment for verifying the electric spark machining workpiece limiting groove.

Description

Technical Field

[0001] This application belongs to the field of underwater electrical discharge machining and cutting technology, specifically relating to an underwater electrical discharge machining and cutting test piece stand and test method. Background Technology

[0002] The internal components of a pressurized water reactor (PWR) in a nuclear power plant are the core of the reactor. The bottom support columns connect the core base plate, flow distribution plate, and basket base plate, secured by locking nuts with anti-loosening mechanisms at their lower ends. When these anti-loosening mechanisms are subjected to prolonged nuclear irradiation and water flow impact, the defective areas may become insufficient to withstand flow-induced vibration and thermal loads, leading to fatigue fracture at the anti-loosening points. Furthermore, the friction and vibration generated by the loosened components under the impact of water flow further exacerbate the damage to the support columns, affecting their support strength.

[0003] Therefore, the anti-loosening structure of the support column locking nut needs to be inspected regularly, and locking nuts that are at risk of loosening should be disassembled and replaced.

[0004] The new anti-loosening cap is cylindrical with a bottom and two side protrusions. Before installation, two symmetrical anti-loosening cap limiting grooves need to be machined on the outside of the locking nut mounting holes pre-installed on the bottom plate of the basket. The lower support frame of the basket exhibits strong radioactivity after long-term reactor operation and requires shielding in several meters of boron-containing water; therefore, the entire machining process must be carried out in boron-containing water. Furthermore, the basket is used to fix fuel assemblies during reactor operation, thus requiring extremely high overall strength. This necessitates minimizing the force exerted on the basket body during any machining process to avoid affecting the mechanical properties of the basket's cylindrical structure. After comparing various methods, Electrical Discharge Machining (EDM) offers advantages such as no contact between the electrode material and the workpiece during machining, short and energy-intensive discharge time, small heat diffusion range, minimal thermal impact on the workpiece, and small, easily recoverable dust particles. It is therefore the most suitable method for machining the limiting grooves in this location. Because variations in current magnitude and electrode materials can affect processing results and quality, and due to the unique nature of nuclear processes, operators need to work remotely. To ensure processing quality and determine appropriate process parameters, testing and verification must be completed before use. This necessitates the invention of a new experimental device as a verification support equipment, tailored to the specific application. Summary of the Invention

[0005] In view of this, this application provides an underwater electrical discharge machining (EDM) cutting test piece stand and test method. By designing a test piece stand specifically for machining and cutting workpiece limiting grooves, the technical problem of the lack of existing support equipment for verifying EDM workpiece limiting grooves is solved.

[0006] This application provides an underwater electrical discharge machining (EDM) cutting test stand, which includes a test frame, an actuator, and a test cutting flange. The actuator and the test cutting flange are positioned and mounted on the test frame. The actuator includes a cutting actuator and a gear transmission mechanism connected to a remote control lever. The cutting actuator performs rotational positioning and machining actions under the drive of the gear transmission mechanism. The gear transmission mechanism assists the cutting actuator in rotating to a precise cutting position under the drive of the remote control lever. The cutting actuator includes an electrode, a positioning sleeve, a clamping spring, a hydraulic cylinder, and a servo valve. The electrode is the end effector of the cutting actuator, and the positioning sleeve is used for positioning the workpiece. The clamping spring is used for clamping the workpiece. The cutting actuator achieves the feed motion throughout the cutting process through the combined action of the hydraulic cylinder and the servo valve. The electrode and the test cutting flange are respectively connected to the two poles of the EDM pulse power supply.

[0007] In one specific embodiment of this application, the actuator further includes a positioning and hoisting mechanism. The positioning and hoisting mechanism is mounted on the gear transmission mechanism and is used for hoisting and positioning.

[0008] In one specific embodiment of this application, the testing frame includes a top plate, a bottom plate, supports, a fixed transition flange, and a supporting transition seat. The bottom plate is supported by multiple supports, and the fixed transition flange is connected to or detached from the mounting hole in the middle of the top plate via lug structures on both sides. A test cutting flange is installed inside the fixed transition flange. When the test cutting flange needs to be installed, the fixed transition 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 transition flange is reinstalled on the top plate to replace the test cutting flange. The supporting transition seat is installed on the bottom plate and is used for positioning and installing the actuator during testing.

[0009] In one specific embodiment of this application, the number of multiple supports is four.

[0010] In one specific embodiment of this application, the gear transmission mechanism includes a gearbox, a bevel gear and a gear shaft installed in the gearbox, and a coupling and a transfer shaft connected to the gear shaft.

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

[0012] The second aspect of this application provides an underwater electrical discharge machining (EDM) cutting test method, which includes steps S10 to S40.

[0013] 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.

[0014] Step S20: The electrode performs an upward feed motion under the combined action of the hydraulic cylinder and the servo valve.

[0015] Step S30: Apply a pulse voltage between the electrodes connected to the two poles of the EDM pulse power supply and the test cutting flange. The material on the surface of the test cutting flange and the electrode surface is locally melted, and the workpiece limiting groove of the workpiece is cut in conjunction with the feed motion.

[0016] Step S40: If the workpiece limiting groove of the workpiece is not machined to the required position, replace the electrode and repeat step S30 until the machining requirements are met.

[0017] In one specific embodiment of this application, step S40 includes step S41.

[0018] Step S41: If the workpiece limiting groove of the workpiece is not properly machined, record the data, replace the electrode, and repeat step S30 until the machining requirements are met.

[0019] In one specific embodiment of this application, the underwater electrical discharge machining cutting test method further includes step S50.

[0020] Step S50: If the workpiece limiting groove of the workpiece is machined in place, record and analyze the data to determine the accurate process parameters.

[0021] In one specific embodiment of this application, before step S10, the underwater electrical discharge machining cutting test method further includes steps S1 and S2.

[0022] Step S1: Position and install the actuator and test cutting flange on the test frame.

[0023] Step S2: Use the positioning and hoisting mechanism to hoist the entire underwater electrical discharge machining cutting test piece frame into the water for experimental operation.

[0024] The beneficial effects of this technical solution are as follows: By designing an underwater electrical discharge machining (EDM) cutting test stand as a support device for verifying the limiting groove of the EDM workpiece, the safety and machining accuracy during actual use are ensured. Furthermore, the test data obtained using the underwater EDM cutting test method provides effective reference data for future EDM methods in deep-water areas within reactors. Attached Figure Description

[0025] Figure 1 The diagram shown is a structural schematic of an underwater electrical discharge machining (EDM) cutting test piece stand provided in an embodiment of this application.

[0026] Figure 2The diagram shown is a structural schematic of the test frame in an underwater electrical discharge machining (EDM) test piece cutting test stand provided in an embodiment of this application.

[0027] Figure 3 The diagram shown is a schematic representation of the actuator in an underwater electrical discharge machining (EDM) test piece cutting test stand according to an embodiment of this application.

[0028] Figure 4 The diagram shown is a structural schematic of the top plate of an underwater electrical discharge machining (EDM) cutting test piece stand provided in an embodiment of this application.

[0029] Figure 5 The diagram shown is a structural schematic of a fixed adapter flange in an underwater electrical discharge machining (EDM) cutting test piece stand provided in an embodiment of this application.

[0030] Figure 6 The diagram shown is a structural schematic of a test cutting flange in an underwater electrical discharge machining (EDM) test specimen stand according to an embodiment of this application.

[0031] Figure 7 The diagram shown is a flowchart of an underwater electrical discharge machining cutting test method provided in an embodiment of this application.

[0032] Figure 8 The diagram shown is a flowchart of an underwater electrical discharge machining cutting test method provided in another embodiment of this application.

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

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] At least one embodiment of this application provides an underwater electrical discharge machining (EDM) test piece cutting platform, see reference. Figures 1 to 6The underwater electrical discharge machining (EDM) cutting test stand includes a test frame 1, an actuator 2, and a test cutting flange 3. The actuator 2 and test cutting flange 3 are positioned and mounted on the test frame 1. The actuator 2 includes a cutting actuator 21 and a gear transmission mechanism 22 connected to a remote control lever 4. The cutting actuator 21 performs rotational positioning and machining actions under the drive of the gear transmission mechanism 22. The gear transmission mechanism 22 assists the cutting actuator 21 in rotating to a precise cutting position under the drive of the remote control lever 4. The cutting actuator 21 includes an electrode 211, a positioning sleeve 212, a clamping spring 213, a hydraulic cylinder 214, and a servo valve 215. The electrode 211 is the end effector of the cutting actuator 21, and the positioning sleeve 212 is used for positioning the workpiece. The clamping spring 213 is used to clamp the workpiece. The cutting actuator 21 achieves the feed motion throughout the cutting process through the combined action of the hydraulic cylinder 214 and the servo valve 215. Electrode 211 and test cutting flange 3 are used to connect to the two poles of the electrical discharge machining pulse power supply, respectively.

[0036] It should be noted that the test frame 1 is a crucial component for supporting and fixing this experimental setup. The actuator 2 can be an EDM actuator. The actuator 2 is the core component of this setup. The test cutting flange 3, as the object to be cut, is installed and fixed in the fixed adapter flange 14 on the test frame 1. The test cutting flange 3 can also be referred to as the flange to be cut. The gear transmission mechanism 22 can assist the electrode 211 in rotating to the accurate cutting position under the drive of the remote operating lever 4.

[0037] According to the technical solution provided in the embodiments of this application, an underwater electrical discharge machining cutting test piece stand is designed as a support device for verifying the workpiece limiting groove of electrical discharge machining (also known as EDM machining), ensuring safety and machining accuracy in actual use.

[0038] In at least one embodiment of this application, reference is made to Figure 2 The test frame 1 includes a top plate 11, a bottom plate 12, supports 13, a fixed transition flange 14, and a support transition seat 15. The bottom plate 12 supports the top plate 11 to a certain height via multiple supports 13. The fixed transition flange 14 is connected to or detached from the mounting hole in the middle of the top plate 11 via lug structures on both sides. A test cutting flange 3 is installed inside the fixed transition flange 14. When the test cutting flange 3 needs to be installed, the fixed transition flange 14 is rotated to remove it from the mounting hole in the middle of the top plate 11. After the test cutting flange 3 is installed, the fixed transition flange 14 is reinstalled onto the top plate 11 to replace the test cutting flange 3. The support transition seat 15 is installed on the bottom plate 12 and is used for positioning and installing the actuator 2 during testing.

[0039] It should be noted that the base plate 12 is the mounting plate for the entire test frame 1. The fixed adapter flange 14 can be quickly connected to or disconnected from 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 this application, the number of multiple support pillars 13 is four.

[0041] In at least one embodiment of this application, reference is made to Figure 3 The actuator 2 also includes a positioning and hoisting mechanism 23. The positioning and hoisting mechanism 23 is mounted on the gear transmission mechanism 22 and is used for hoisting and positioning. Thus, the positioning and hoisting mechanism 23 can be used for hoisting and positioning during subsequent actual use.

[0042] In at least one embodiment of this application, reference is made to Figure 3 The gear transmission mechanism 22 includes a gearbox 221, a bevel gear 222 and a gear shaft 223 installed in the gearbox 221, and a coupling 224 and a transfer shaft 225 connected to the gear shaft 223.

[0043] In at least one embodiment of this application, the number of test cutting flanges 3 is multiple. Thus, by providing multiple test cutting flanges 3, these multiple test cutting flanges 3 can be used in multiple test trials.

[0044] At least one embodiment of this application also provides an underwater electrical discharge machining (EDM) cutting test method, which is performed using the underwater EDM cutting test bench described in the above embodiments. The test environment for this underwater EDM cutting test method can be boron-containing deionized water at a depth of less than 10 meters.

[0045] refer to Figure 7 The underwater electrical discharge machining cutting test method includes the following steps S10 to S40.

[0046] Step S10: Rotate and position the cutting actuator 21 under the drive of the gear transmission mechanism 22 to ensure that the electrode 211 is aligned with the cutting station.

[0047] For example, the gear transmission mechanism 22 assists the cutting actuator 21 in rotational positioning to ensure that the electrode 211 is aligned with the processing position. Step S10 is... Figure 8 The steps for rotating and aligning the actuator 2.

[0048] In step S20, electrode 211 performs an upward feed motion in cooperation with hydraulic cylinder 214 and servo valve 215.

[0049] For example, after electrode 211 is aligned with the cutting station, electrode 211 moves upward under the drive of hydraulic cylinder 214. Step S20 is... Figure 8The upward feeding step of the actuator 2.

[0050] Step S30: Apply a pulse voltage between the electrodes 211, which are connected to the two poles of the electrical discharge machining pulse power supply, and the test cutting flange 3. The material on the surface of the test cutting flange 3 and the surface of the electrodes 211 is locally melted, and the workpiece limiting groove of the workpiece is cut in conjunction with the feed motion.

[0051] For example, when the electrical discharge machining pulse power supply is energized, a pulse voltage is applied between electrode 211 and the test cutting flange 3. The material on the surface of the test cutting flange 3 and the surface of electrode 211 is locally melted, and the limiting groove is cut in conjunction with the feed motion, thus realizing the machining of the workpiece limiting groove. Step S30 is... Figure 8 The steps for electro-cutting of the 211-type electrode.

[0052] It should be noted that the workpiece limiting groove can be an anti-loosening cap limiting groove.

[0053] Step S40: If the workpiece limiting groove of the workpiece is not properly processed, then replace electrode 211 multiple times and repeat step S30 until the processing requirements are met.

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

[0055] In some embodiments, the machining accuracy and quality achieved by a single electrode 211 under different conditions, as well as the machining time, can be tested according to a pre-designed feed rate and pulse current. Test items may include testing the machining quality of the cutting groove 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 electrodes required to be replaced throughout the machining process.

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

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

[0058] Step S41: If the workpiece limiting groove of the workpiece is not properly machined, record the data, replace the electrode, and repeat step S30 until the machining requirements are met.

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

[0060] In at least one embodiment of this application, the underwater electrical discharge machining cutting test method further includes step S50.

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

[0062] For example, we can first determine whether the processing is in place. If the processing is in place (i.e., the processing requirements are met), then record and analyze the data to determine the accurate process parameters.

[0063] It should be noted that recording and analyzing data helps determine the appropriate electrode material, pulse current parameters, feed rate parameters, number of replacements, and processing time.

[0064] By performing the above specific operations, a reasonable processing technology can be found to ensure the processing quality and accuracy of the workpiece limiting groove.

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

[0066] Step S1: Position and install the actuator 2 and the test cutting flange 3 on the test frame 1.

[0067] Specifically, the actuator 2 is first positioned and installed on the test frame 1 (i.e. Figure 8 (Step 2 for positioning the actuator) and then position and install the test cutting flange 3 (also known as the cutting test flange) on the test frame 1 (i.e. Figure 8 (Steps for positioning the test flange in the middle of the cutting process).

[0068] For example, the actuator 2 is positioned, installed, and locked onto the test frame 1. The test cutting flange 3 is used to simulate the plate outside the pre-installed locking nut mounting holes on the bottom plate of the suspended platform. The test cutting flange 3 is bolted into the fixed transition flange 14, and secured to the top plate 11 of the frame using the lug structures on both sides of the fixed transition flange 14. Ensure that the relative position of the actuator 2 and the test cutting flange 3 is the same as the actual underwater position within the reactor.

[0069] Step S2: Use the positioning and hoisting mechanism 23 to hoist the entire underwater electrical discharge machining and cutting test piece frame into the water for experimental operation.

[0070] It should be noted that the combination of the technical features in the embodiments of this application is not limited to the combination methods described in the embodiments of this application or the combination methods described in specific embodiments. All technical features described in this application can be freely combined or combined in any way, unless they contradict each other.

[0071] As indicated in this application and claims, unless the context clearly indicates otherwise, the words “a,” “an,” and / or “the” do not specifically refer to the singular and may also include the plural. Generally speaking, the term “comprising” only indicates that it includes the explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0072] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications or equivalent substitutions made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An underwater electro-discharge machining cutting test piece rack characterized by comprising: The test frame, the actuator and the test cutting flange are provided, The actuator comprises a cutting actuator, a gear transmission mechanism connected with a remote operation long rod, the cutting actuator is used for performing rotating positioning and processing action under the driving of the gear transmission mechanism; the gear transmission mechanism is used for assisting the cutting actuator to rotate to an accurate cutting station under the driving of the remote operation long rod; the actuator further comprises a positioning hoisting mechanism, the positioning hoisting mechanism is installed on the gear transmission mechanism and is used for hoisting and positioning; the test cutting flange is used for simulating the plate outside the pre-installed locking nut mounting hole of the basket bottom plate; The cutting actuator 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 actuator; the positioning sleeve is installed in the middle gap of the electrode and is used for positioning the test cutting flange; the compression spring is installed below the positioning sleeve and is used for compressing the test cutting flange; the cutting actuator realizes the feeding motion in the cutting process of the cutting actuator under the cooperation of the hydraulic cylinder and the servo valve; the electrode and the test cutting flange are used for connecting two poles of an electric spark machining pulse power source respectively, In the working state, pulse voltage is applied between the electrode and the test cutting flange connected to two poles of an electric spark machining pulse power source respectively, the materials of the surface of the test cutting flange and the surface of the electrode are locally melted, and the cutting of the workpiece limiting groove of the test cutting flange is performed in cooperation with the feeding motion.

2. The test piece stage for electro-discharge machining under water according to claim 1, wherein 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 separated with the mounting hole in the middle of the top plate through the lug structure on both sides; the support adapter seat is installed on the bottom plate and is used for positioning and installing the actuator during the test; the test cutting flange is installed in the fixed adapter flange, when the test cutting flange needs to be installed, the fixed adapter flange is rotated and separated 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.

3. An underwater electro-discharge machining test piece stage according to claim 2, wherein The number of the plurality of support columns is four.

4. The underwater electro-discharge machining test piece rack according to claim 1, wherein 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.

5. An underwater electro-discharge machining cutting test piece rack according to any one of claims 1 to 4, characterized in that, The number of the test cutting flanges is multiple.

6. An underwater electro-discharge machining cutting test method characterized by comprising: The underwater electric discharge machining cutting test piece rack is executed by using the underwater electric discharge machining cutting test method according to any one of claims 1 to 5, the underwater electric discharge machining cutting test method comprises: Step S1, positioning and installing the actuator and the test cutting flange on the test frame; Step S2, hoisting the entire underwater electric discharge machining cutting test piece rack to the water for experimental operation by using the positioning hoisting mechanism; Step S10, the cutting actuator is rotated and positioned under the drive of the gear transmission mechanism, ensuring that the electrode is aligned with the cutting station; Step S20, the electrode is moved upward under the cooperation of the hydraulic cylinder and the servo valve; Step S30, a 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 material on the surface of the test cutting flange and the electrode is partially melted, and the cutting of the workpiece limiting groove of the test cutting flange is carried out in cooperation with the feeding motion; Step S40, if the machining of the workpiece limiting groove of the test cutting flange fails to be machined in place, the electrode is replaced, and step S30 is executed again until the machining requirement is met.

7. The underwater electro-discharge machining cutting test method according to claim 6, wherein Step S40 includes: Step S41, if the machining of the workpiece limiting groove of the test cutting flange 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 met.

8. The method of claim 6, wherein the method is a test method for underwater electro-discharge machining cutting. Also includes: Step S50, if the machining of the workpiece limiting groove of the test cutting flange is in place, the data is recorded and analyzed to determine the accurate process parameters.

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