CN-121670042-B - High-radiation underwater non-contact electric discharge machining method and device

CN121670042BCN 121670042 BCN121670042 BCN 121670042BCN-121670042-B

Abstract

The application belongs to the technical field of special processing, and discloses a high-radiation underwater non-contact electric discharge processing method and a device, wherein, the method sets a processing workpiece in a high-radiation underwater environment and configures a processing electrode system, establishes a discharge channel, carries out etching processing on the processing workpiece, collects physical signals of the etching processing process and generates middleware data, introduces aqueous medium suspension containing nano particles, the gap of the discharge channel is dynamically regulated and controlled to be kept constant, intermediate data are transmitted to a remote monitoring platform through a high-radiation shielding communication link, the remote monitoring platform carries out quality assessment on the stability of the discharge channel based on the intermediate data, and a correction instruction is generated. The application provides real-time monitoring and data support for the processing process, and improves the processing quality and efficiency.

Inventors

ZHANG WEI
Dong Junbin
HU MINGLEI
SHENG JIANHUA
WEN JIE
ZHAO QIANG
BIAN CHUNHUA
ZHANG HONGWEI
YANG QIZHEN
GE LIANWEI

Assignees

中核核电运行管理有限公司

Dates

Publication Date: 20260508
Application Date: 20260205

Claims (6)

1. A high-emissivity underwater non-contact electrical discharge machining method, comprising: The method comprises the steps of S1, setting a processing workpiece in a high-radiation underwater environment, and configuring a processing electrode system, wherein the processing electrode system comprises a main electrode and an auxiliary electrode, the main electrode and the auxiliary electrode alternately work in a switching mode in the processing process and are used for dispersing a discharge path and reducing single-point electrode abrasion, the switching mode is self-adaptive switching, the self-adaptive switching is judged based on current density and temperature rise data of the processing electrode system, and the process comprises a preheating stage, a stable processing stage and an annealing stage; s2, a discharge channel is established between the machining electrode system and the machined workpiece, and the machined workpiece is etched and removed by adopting a pulse power supply signal; s3, collecting physical signals in the etching process through an integrated sensing system and generating middleware data, wherein the middleware data comprise surface roughness parameters, removal depth parameters, heat affected zone width parameters and medium parameters; s4, introducing an aqueous medium suspension containing nano particles into the discharge channel, wherein the particle size range of the nano particles is 20-200 nm, the mass concentration range of the nano particles is 0.1-2%, the aqueous medium suspension is circulated in a bidirectional flow mode, and opposite flow fields are formed at two ends of the discharge channel through the bidirectional flow circulation, so that the uniformity of the temperature field and the particle distribution of the suspension is improved; S5, dynamically regulating and controlling the gap of the discharge channel through a feedback control algorithm based on middleware data so as to maintain constant; s6, transmitting the intermediate data to a remote monitoring platform through a high-radiation shielding communication link, and performing quality assessment on the stability of the discharge channel by the remote monitoring platform based on the intermediate data, and generating a correction instruction, wherein the quality assessment adopts a weighting function model, and the formula of the weighting function model is as follows: Wherein Q is a quality score, R a is a surface roughness parameter, h is a removal depth parameter, w is a heat affected zone width parameter, alpha is a weight coefficient, beta is a weight coefficient, gamma is a weight coefficient, and alpha+beta+gamma=1.
2. The method of claim 1, wherein the pulsed power supply signal is in a multi-level modulation topology comprising a front full-bridge inverter circuit and a back Buck chopper circuit.
3. The method of claim 1, wherein the nanoparticles are insulating ceramic or metal oxide particles, and the aqueous medium suspension is used to enhance breakdown strength and insulation properties and to adjust the flow rate based on the medium parameters.
4. The method of claim 1, wherein the feedback control algorithm uses a fuzzy PID control algorithm, the fuzzy PID control algorithm takes as input the deviation and the deviation change rate of the voltage signal, the current signal and the medium flow rate signal, and the adjustment formula of the PID controller is: Wherein u (k) is the output feeding speed control quantity at the kth sampling time, e (k) is the deviation between the set gap of the discharge channel and the actual gap, delta e is the deviation change rate, delta t is the sampling period, e (j) is the deviation value, j is the accumulation index in the integral summation item; Representing the cumulative sum of all deviation values multiplied by the sampling period from the 0 th sampling time to the current kth sampling time, K p (e, Δe) being a scaling factor, K i (e, Δe) being an integration factor, and K d (e, Δe) being a differentiation factor.
5. A high-emissivity underwater non-contact electrical discharge machining apparatus, characterized in that it comprises, based on the method according to any one of claims 1 to 4: the processing electrode system is arranged in a high-radiation underwater environment and comprises a main electrode and an auxiliary electrode which are used for alternately working, wherein the main electrode and the auxiliary electrode alternately work in a switching mode; the pulse power supply system is connected with the processing electrode system and is used for providing pulse power supply signals required by etching processing; The integrated sensing system comprises an electric sensor, a fluid sensor, an optical sensor and an acoustic sensor and is used for collecting physical signals in the processing process in real time; a nanosuspension system for supplying an aqueous medium suspension containing nanoparticles to the discharge channel and supporting bi-directional flow circulation; the feedback controller is connected with the integrated sensing system and the processing electrode system and is used for dynamically regulating and controlling the discharge channel gap based on the acquired middleware data; the remote monitoring platform is connected with the feedback controller through a high-radiation shielding communication link and is used for receiving middleware data, performing quality evaluation and issuing a correction instruction.
6. The high-emissivity underwater non-contact electrical discharge machining apparatus of claim 5, wherein the feedback controller incorporates a fuzzy PID control algorithm module for performing dynamic gap regulation.

Description

High-radiation underwater non-contact electric discharge machining method and device Technical Field The application belongs to the technical field of special machining, and particularly relates to a high-radiation underwater non-contact electric discharge machining method and device. Background In the field of electric discharge machining, non-contact electric discharge technology has been applied to surface treatment and repair of high hardness metals, complex cavities and difficult-to-machine materials. The principle is that pulse arc discharge is formed between the electrode and the workpiece to make the surface layer of the workpiece instantaneously melt and gasify, so as to realize the removal of local materials. The traditional non-contact discharge can be performed in air, an oil medium or a common water medium, and has the advantages of no need of a contact cutter, small processing stress, strong adaptability and the like. In the fields of nuclear energy, ocean engineering, aerospace and the like, the technology is gradually introduced to replace mechanical cutting. As the service cycle of the nuclear power plant is extended and the decommissioning process is increased, the underwater processing requirements continue to rise. The underwater environment can shield radiation and reduce a heat affected zone, and has cooling and insulating properties, so that underwater electric discharge machining becomes an important direction. Studies have shown that the use of pulsed power supplies in combination with aqueous media can achieve material removal and maintain surface controllability. In nuclear power maintenance and decommissioning engineering, attempts have been made to cut, slot and partially remove highly radioactive equipment using underwater electrical discharge machining, and partial results have shown that this approach can reduce the impact of radiation on personnel and maintain some safety. However, in high-emissivity underwater conditions, the adaptability of conventional non-contact electrical discharge machining is still limited. Especially in the decommissioning scene of nuclear facilities, the residual radioactivity of equipment is high, and the environment is complicated, and discharge process stability is poor, and the processing clearance is difficult to invariable. Particularly under the condition of radiation field intensity, arc discharge is easy to interfere, so that the surface roughness fluctuation is obvious, the processing efficiency is reduced, and the process uncontrollability is enhanced. This instability not only affects the quality of the process, but also places higher demands on the remote operating system. Therefore, the prior art still lacks a method capable of ensuring discharge stability and machining precision when dealing with high-radiation underwater scenes, and particularly lacks a non-contact discharge machining solution suitable for retired environments. Disclosure of Invention The application aims to provide a high-radiation underwater non-contact electric discharge machining method and device, which solve the problems of rapid electrode abrasion, unstable electric discharge and poor machining precision in high-radiation underwater electric discharge machining. In order to achieve the above object, the present application provides the following technical solutions: in a first aspect, the present application provides a high-emissivity underwater non-contact electrical discharge machining method, comprising: The method comprises the following steps of S1, setting a machining workpiece in a high-radiation underwater environment and configuring a machining electrode system, wherein the machining electrode system comprises a main electrode and an auxiliary electrode, and the main electrode and the auxiliary electrode alternately work in a switching mode in the machining process and are used for dispersing discharge paths and reducing single-point electrode abrasion; s2, a discharge channel is established between the machining electrode system and the machined workpiece, and the machined workpiece is etched and removed by adopting a pulse power supply signal; S3, collecting physical signals in the etching process through an integrated sensing system and generating middleware data; s4, introducing aqueous medium suspension containing nano particles into a discharge channel; S5, dynamically regulating and controlling the gap of the discharge channel through a feedback control algorithm based on middleware data so as to maintain constant; And S6, transmitting the intermediate data to a remote monitoring platform through a high-radiation shielding communication link, and performing quality assessment on the stability of the discharge channel by the remote monitoring platform based on the intermediate data and generating a correction instruction. As one embodiment, the intermediate piece data includes a surface roughness parameter, a removal depth parameter, a heat aff