Ultrasonic electrolysis combined machining monitoring method and application

Abstract

The invention provides an ultrasonic electrolysis combined machining process monitoring method and application, and belongs to the field of electrolytic machining. According to the main principle, a strain gauge is adhered to the surface of a machined workpiece to capture a strain signal generated along with the change of a machining gap between a tool electrode and the workpiece in the machining process in real time, and the strain signal is converted into an observable strain curve. And the relation between the strain signal response and the thickness of the electrolytic machining workpiece is established, and data support is provided for evaluating the machining effect of the standard workpiece. Ultrasonic electrolysis process parameters are optimized through signals collected in real time, so that the surface and machining precision is improved, and the follow-up working efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrolytic machining and material performance testing technology, in particular to an ultrasonic electrolytic composite machining process monitoring method and application. BACKGROUND

[0002] Electrochemical machining is a non-contact machining technology at room temperature based on the principle of electrochemical dissolution. In the absence of direct mechanical action between the tool and the workpiece and the influence of macroscopic cutting force, the generation of machining stress and residual stress can be effectively avoided, and it is suitable for the forming of difficult-to-machine materials with high surface integrity requirements. For titanium alloys, nickel-based superalloys and metal matrix composites, etc., using electrolytic machining method to prepare samples with standard geometric shape can realize high efficiency and high precision machining, and provide reliable sample basis for subsequent material performance testing and evaluation.

[0003] Among the many influencing factors of ultrasonic electrolytic composite machining, the reasonable design of the overall clamp and the ultrasonic system can affect the surface quality of the workpiece machining, thereby affecting the tensile fatigue test of the workpiece. For the ultrasonic electrolytic composite machining method (see patent "Ultrasonic assisted electrolytic machining device and method for reciprocating abrasive polishing" Application No. 2023111136511.1 Applicant Nanjing University of Aeronautics and Astronautics Inventor Ren Mingzhu Zhu Dong Xu Zhengyang), the device controls the ultrasonic vibration of the cathode while making periodic reciprocating motion, and the reciprocating polishing system realizes the reciprocating flow of abrasive particles in the machining area. By adjusting the ultrasonic power to control cavitation, remove the product layer and improve the uniformity of the flow field; Suzhou University of Electronic Science and Technology proposes a device and method for ultrasonic electrolytic machining of metal surface micro-pit array (see patent "Metal surface micro-pit array machining device and method" Application No. 201810921628.3 Applicant Suzhou University of Electronic Science and Technology Inventor Zhang Xifang Li Hua Yin Zhen, etc.), which provides a metal surface micro-pit array machining device and method. A micro-hole template is provided between the tool cathode and the cathode to solve the problems of high machining cost and poor controllability in the current electrolytic method for machining micro-pit array on the metal surface; Nanjing University of Aeronautics and Astronautics proposes an ultrasonic electrolytic composite micro-machining method (see patent "Ultrasonic electrolytic composite micro-machining device" Application No. 200620068677.X Applicant Nanjing University of Aeronautics and Astronautics Inventor Zhu Yongwei Yun Naizhang Shen Maosong, etc.), which has the advantages of high precision and efficiency, low cost and good machining surface quality.

[0004] The above ultrasonic electrolytic composite machining is respectively proposed for blade workpieces, metal surface array machining and micro-machining devices, and current ultrasonic electrolytic machining technology can improve the surface quality of the machined workpieces, but still has limitations: it cannot judge in real time during the machining process whether the workpiece machining size has met the accuracy requirements of subsequent performance tests. The existing method has not combined the real-time signals (such as strain response) in the machining process with the simulation model (simulated stress and strain values obtained by workpiece deformation), and it is also difficult to dynamically adjust the process parameters according to the test standards, resulting in that the machining and testing links cannot be directly connected and need to be post-processed. SUMMARY

[0005] The present application optimizes the ultrasonic electrolytic process parameters through real-time collected signals to improve the surface and machining precision and improve the machining and subsequent work efficiency of the ultrasonic electrolytic composite machining process monitoring method and application.

[0006] An ultrasonic electrolytic composite machining process monitoring method, the workpiece has a structure of thick at both ends and thin in the middle, and the method comprises the following steps: step 1, strain-thickness standard curve calibration: taking one workpiece from a batch of workpieces to be machined as a calibration workpiece, installing strain gauges on the left and right ends near the machining area of the workpiece, and connecting the strain gauges with the signal input end of a dynamic signal acquisition system to acquire strain values in real time during the machining process and generate a strain curve; the horizontal coordinate of the strain curve is machining time, and the vertical coordinate is stress value; comparing the real-time acquired strain values with simulation data of the machined workpiece, preliminarily judging the thickness of the workpiece, actually measuring when the thickness reaches a preset thickness range, continuing to measure when the thickness does not reach a target thickness, stopping machining until the target thickness is reached, and taking the current curve as a standard strain curve of the target thickness; the simulation data refers to structure deformation simulation of the machining area of the workpiece to obtain simulation strain values from the original workpiece to the target value; step 2, actual machining: taking one workpiece from a batch of workpieces to be machined as an actual machining workpiece, installing strain gauges on the left and right ends near the machining area of the workpiece, and connecting the strain gauges with the signal input end of a dynamic signal acquisition system to acquire strain values in real time during the machining process, generating a strain curve by time and stress values through software, and judging whether the target thickness is reached by comparing the strain data with the standard strain curve of the target thickness.

[0007] The ultrasonic electrolytic composite machining process monitoring method, characterized in that: during the machining process, the workpiece is clamped and held by a clamp body, wherein the clamp body is composed of a left clamp unit, a right clamp unit, an upper cover plate and a lower cover plate; tool cathodes are respectively located on the front and rear sides of the workpiece to perform ultrasonic electrolytic composite machining; the upper cover plate is provided with a liquid inlet, and sliders are respectively arranged on the front and rear cathode feeding channels to reduce the flow of electrolyte to the two cathodes.

[0008] The ultrasonic electrolytic composite machining process monitoring method is used for ultrasonic electrolytic composite machining, and is characterized in that: machining parameters such as machining voltage, cathode feeding speed, liquid feeding pressure and parameters such as ultrasonic wave amplitude and frequency are optimized, so as to improve the surface quality of a machined workpiece.

[0009] The present application has the following advantages: (1) The main principle of the present application is to adhere strain gauges and matched wires to the surface of a machined workpiece, to capture strain signals generated due to changes in a machining gap between a tool electrode and the workpiece in real time during machining, and to convert the strain signals into observable strain curves. A relationship between strain signal responses and the thickness of an electrolytic machined workpiece is established, to provide data support for evaluating the machining effect of a standard workpiece. The method can effectively guarantee the dimensional accuracy and surface quality of ultrasonic electrolytic composite machining.

[0010] (2) The present application can be applied to various types and different materials (such as stainless steel, high-temperature alloy, titanium alloy and other conductive materials) by adjusting the tool cathode profile and the fixture, can accurately match the structural characteristics of standard test pieces, blades and other complex components, and the machined standard test pieces can be directly used for subsequent performance tests such as tensile tests, greatly simplifying the subsequent test and processing links.

[0011] (3) Under ultrasonic electrolytic composite machining, the tool cathode is structurally designed to be matched and connected with an ultrasonic vibration system, and can be used for electrolytic machining tests of materials of various types of surfaces such as planes, curved surfaces and curved surfaces. BRIEF DESCRIPTION OF DRAWINGS

[0012] ATTACHMENT Figure 1 The present application relates to an overall assembly schematic diagram of ultrasonic electrolytic composite machining ATTACHMENT Figure 2 The present application relates to an assembly schematic diagram of an ultrasonic electrolytic machined workpiece Reference numerals in the drawing: 1, ultrasonic amplitude transformer, 2, tool cathode, 3, tool fixture, 4, strain gauge and wire, 5, dynamic signal test system, 6, output device. SPECIFIC IMPLEMENTATION METHOD

[0013] The specific implementation process of the present application will be described in detail as follows in combination with the drawings: In order to achieve the above-mentioned application purposes, the present application is implemented by the following technical solutions: An ultrasonic electrolytic composite machining device, characterized in that it comprises a machine tool main body, an ultrasonic vibration system, an electrolytic machining device, a workpiece clamping device and a control system. The ultrasonic vibration system comprises an ultrasonic generator, an ultrasonic transducer, an amplitude changer and a tool cathode. The tool clamp is used to install the adaptive basic test piece and the corresponding tool cathode. The electrolytic machining system comprises a power supply system and an electrolyte circulation system, and the power supply can realize accurate adjustment of parameters. The workpiece clamping device realizes flow field optimization through structural design. The control system is connected with each system respectively to realize multi-parameter collaborative control.

[0014] The process of testing the ultrasonic electrolytic composite machining workpiece and tensile properties by using the ultrasonic electrolytic composite machining detection method and application of the present application comprises the following steps: Step one, device assembly and debugging: according to the structure shown in the attached Figure 1 The ultrasonic amplitude changer, tool cathode and tool clamp are assembled to form the machining device. Strain gauges and wires are adhered to both sides of the workpiece machining area, and adaptive planar tool cathodes are installed corresponding to the profile. The ultrasonic vibration system, power supply system and tool clamp are connected.

[0015] Step two, set the machining parameter range, and carry out tests under different liquid inlet pressures, machining voltages and cathode feeding speeds; Step three, test machining: (1) Perform strain-thickness standard curve calibration A workpiece is taken from the batch of workpieces to be machined as a calibration workpiece. Strain gauges are installed on both ends of the workpiece near the machining area and connected to the signal input end of the dynamic signal acquisition system to collect strain values in real time during the machining process and generate a strain curve. The horizontal coordinate of the strain curve is the machining time, and the vertical coordinate is the stress value. Compare the real-time collected strain values with the simulation data of the machined workpiece to preliminarily judge the thickness of the workpiece. When the target thickness is reached, the actual measurement is carried out. When the target thickness is not reached, the measurement is repeated until the target thickness is reached and the machining is stopped. The current curve is taken as the standard strain curve of the target thickness. The above simulation data refers to the structural deformation simulation of the machining area of the workpiece to obtain the simulation strain values from the original workpiece to the target value. (2) Actual machining A workpiece is taken from the batch of workpieces to be machined as an actual machining workpiece. Strain gauges are installed on both ends of the workpiece near the machining area and connected to the signal input end of the dynamic signal acquisition system to collect strain values in real time during the machining process. The strain curve is generated by the software through time and stress values. Whether the target thickness is reached is judged by comparing the strain data with the standard strain curve of the target thickness.

[0016] Step four, performance testing: after processing, the strain curve output by the dynamic signal detection system is obtained, the workpiece meeting the requirements is cleaned, and then the surface quality detection and tensile fatigue test are performed.

Claims

1. A method for monitoring an ultrasonic electrolytic composite machining process, wherein the workpiece has a structure that is thick at both ends and thin in the middle, characterized in that... Includes the following steps: Step 1: Calibration of the strain-thickness standard curve One workpiece is selected from the batch of workpieces to be processed as a calibration workpiece. Strain gauges are installed at the left and right ends near the processing area of ​​the workpiece and connected to the signal input terminal of the dynamic signal acquisition system. The strain values ​​during the processing are collected in real time to generate a strain curve. The horizontal axis of the strain curve is the processing time, and the vertical axis is the stress value. The real-time collected strain values ​​are compared with the simulation data of the processed workpiece to make a preliminary judgment on the workpiece thickness. When the preset thickness range is reached, the actual measurement is performed. If the target thickness is not reached, processing continues and the measurement is repeated until the target thickness is reached and processing stops. The current curve is used as the standard strain curve for generating the target thickness. The above simulation data refers to the structural deformation simulation of the workpiece's machining area, which yields the simulated strain values ​​from the original part to the target value. Step 2, Actual Processing One piece is selected from the batch of workpieces to be processed as the actual workpiece to be processed. Strain gauges are installed on both the left and right ends near the processing area of ​​the workpiece and connected to the signal input terminal of the dynamic signal acquisition system. The strain values ​​during the processing are collected in real time. The software generates a strain curve based on the time and stress values. The strain data is compared with the standard strain curve of the target thickness to determine whether the target thickness has been achieved.

2. The method for monitoring the ultrasonic electrolytic composite processing according to claim 1, characterized in that: During the processing, the workpiece is held by the clamping body, which consists of a left clamping unit, a right clamping unit, an upper cover plate, and a lower cover plate. The tool cathodes are located on the front and rear sides of the workpiece, respectively, for ultrasonic electrolytic composite machining. The above-mentioned liquid inlet is set up, and epoxy pressure plates of a certain thickness are set on the front and rear cathode feed channels to reduce the flow of electrolyte to the cathodes on both sides.

3. The ultrasonic electrolytic composite machining process monitoring method according to claim 1 or 2 is used in ultrasonic electrolytic composite machining, characterized in that: The surface quality of the machined workpiece can be improved by optimizing machining parameters, including machining voltage, cathode feed speed, and liquid inlet pressure, as well as ultrasonic amplitude and frequency.

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