CN118893259A - Electrolytic machining electrode and removal method for removing recast layer of closed contour straight surface component - Google Patents

Abstract

The invention discloses an electrolytic machining removing electrode and a method for a recast layer of a straight line surface member with a closed contour, wherein the electrolytic machining electrode comprises an electrolytic electrode, an insulating jet electrode and a ranging electrode, the ranging electrode comprises a micro telescopic shaft arranged on the electrolytic electrode, and a micro touch sensor is arranged at the telescopic end of the micro telescopic shaft; controlling the electrolytic machining electrode to approach the surface of the contour to be machined until the micro-touch sensor contacts the surface of the contour, continuously feeding the electrolytic machining electrode to the surface of the contour to be machined until a machining gap required by machining is reached, enabling the electrolytic electrode to be always opposite to the surface of the contour to be machined in the electrolytic machining process, and removing the electrolytic machining electrode by electrolytic machining of the recast layer along a closed contour track; the electrolytic stripping method has the advantages of high precision of electrolytic stripping of the recast layer, good surface roughness stripping and high stripping efficiency; the thickness of the base material of the lower layer of the recast layer can be accurately controlled.

Description

An electrolytic machining electrode and removal method for removing the recast layer of a closed contour straight surface component

Technical Field

The invention relates to the technical field of electrolytic machining, in particular to an electrolytic machining electrode for removing a recast layer of a closed contour straight surface component and a removal method.

Background Art

Processing methods such as wire EDM and laser processing melt metal materials and then remove them through instantaneous high temperatures generated by instantaneous accumulation of energy. The metal materials that are not discharged from the processing area will re-solidify on the processed surface to form a loose layer and a melted solidified layer, collectively referred to as a recast layer, recast layer or molten layer. Due to the existence of the recast layer, the wear resistance and corrosion resistance of the workpiece are seriously reduced. In addition, the micro-pits, micro-pores, micro-cracks and other defects on the microscopic surface of the recast layer seriously reduce the accuracy and surface quality of the workpiece, greatly affecting the fatigue strength and service life of the workpiece.

Closed contour ruled surface components are typical ruled surface component types, such as lubricating oil pump rotor slots, cycloidal pump inner and outer rotors, etc., and are widely manufactured using special processing methods such as EDM wire cutting and laser cutting. The aerospace field has strict regulations on the surface quality of workpieces, and the recast layer produced by the above manufacturing methods often needs to be removed through post-processing processes to meet the delivery index requirements of the parts. Common methods include abrasive flow grinding, electrolytic machining, chemical pickling, etc.

As the advantages of electrolytic machining in removing recast layers are gradually recognized, wire electrode electrolytic machining technology has been applied by researchers to remove recast layers of straight-grained surface components. Patent publication number CN112059339B discloses a winding wire electrode and method for electrospark-electrolytic synchronous composite cutting, which uses two mutually wound electrode wires to perform electrospark electrolytic synchronous machining on the workpiece, specifically, the recast layer after electrospark cutting is electrolytically removed by an electrode wire with weaker conductivity. However, since the thickness of the recast layer is usually in the micron level, it is difficult to accurately control the machining gap with conventional wire electrode electrolytic machining fluids. Therefore, there is a problem that the electrolytic machining gap between the electrolytic electrode and the machining contour surface cannot be accurately controlled. The electrolytic electrode is prone to over-electrolyze the contours of the machined area and the unmachined area, causing stray corrosion to the contours of the machined area and the unmachined area of the workpiece. The precision of removing the recast layer is low, the surface roughness is poor, and the removal efficiency is low. It is also difficult to control the amount of base material removed under the recast layer during the removal process.

Summary of the invention

The technical problem to be solved by the present invention is to overcome the existing defects and provide an electrolytic machining electrode and a removal method for removing the recast layer of a closed contour straight surface component. The electrolytic machining gap between the electrolytic electrode and the machining contour surface can be accurately adjusted, the current density in the machining area is high, and the electric field in the electrolytic electrode machining area is shielded by the insulating jet electrode, thereby reducing stray corrosion to the contours of the machined area and the unmachined area; the electrolytic removal of the recast layer has high precision, good surface roughness and high removal efficiency; and the removal thickness of the lower layer of the base material of the recast layer can be accurately controlled, which can effectively solve the problems in the background technology.

To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an electrolytic machining electrode for removing the recast layer of a closed contour straight surface component, the electrolytic machining electrode is composed of an electrolytic electrode, an insulating jet electrode and a ranging electrode, the electrolytic electrode is a solid semicircular cylindrical structure, the insulating jet electrode is a semicircular tubular structure, and the outer diameter of the insulating jet electrode is adapted to the outer diameter of the electrolytic electrode, and the electrolytic electrode and the insulating jet electrode are an integrated cylindrical structure; the ranging electrode includes a plurality of micro-telescopic shafts arranged on the electrolytic electrode, the micro-telescopic shafts are arranged along the radial direction of the electrolytic electrode, and the telescopic ends of the micro-telescopic shafts are provided with micro-touch sensors; a micro-jet structure connected to its internal cavity is opened on the circumferential outer wall of the insulating jet electrode along its radial direction.

Furthermore, the ranging electrode includes a semi-annular clamping ring, and a semi-annular groove adapted to the clamping ring is opened on the circumferential outer wall of the electrolysis electrode. The clamping ring is embedded in the semi-annular groove. The outer diameter of the clamping ring is the same as that of the electrolysis electrode and they are concentric with each other. The material of the clamping ring and the electrolysis electrode is the same; the micro-telescopic shafts are all arranged on the clamping ring.

Furthermore, a plurality of guide grooves matching the micro-telescopic shaft structure are provided on the outer circumferential wall of the retaining ring along its radial direction, the micro-telescopic shaft is nested in the guide grooves, a shaft shoulder is provided at the inner end of the micro-telescopic shaft, and a return spring is nested at the inner end of the micro-telescopic shaft.

Furthermore, the micro-jet structure is a micro-jet hole or a micro-slit structure.

To achieve the above object, the present invention also provides the following technical solution: a method for removing the recast layer of a closed contour straight surface component using the above electrolytic machining electrode, comprising the following steps:

Step 1: Select a closed contour straight surface component with a recast layer on the surface of the same batch as a sample of the workpiece to be processed, and use a metallographic sample preparation method to obtain a cross section of the recast layer to obtain the thickness value of the recast layer of the workpiece;

Step 2: After the electrolytic machining electrode and the workpiece are clamped, the electrolytic electrode is electrically connected to the negative electrode of the pulse power supply, the workpiece is electrically connected to the positive electrode of the pulse power supply, and the electrolyte is injected into the electrolyte tank to immerse the machining area; the numerical control system drives the electrolytic machining electrode to move to the contour surface to be machined of the workpiece, and drives the electrolytic machining electrode to rotate so that the electrolytic electrode is facing the contour surface to be machined, and the numerical control system controls the electrolyte circulation system to inject electrolyte into the port of the insulating jet electrode, and the electrolyte in the insulating jet electrode is ejected out through the jet structure;

Step 3: The numerical control system controls the electrolytic machining electrode to approach the contour surface to be machined until the micro-touch sensor of the distance measuring electrode touches the contour surface, and the micro-touch sensor transmits a signal to the numerical control system. Since the initial distance between the micro-touch sensor and the electrolytic electrode is known, the initial machining gap value between the electrolytic machining electrode and the contour surface to be machined can be displayed by the numerical control system.

Step 4: The numerical control system controls the electrolytic machining electrode to continuously feed toward the contour surface to be machined, and adjusts the machining gap value between the electrolytic machining electrode and the machining contour surface by contracting the micro-telescopic shaft until the machining gap required by the machining is reached;

Step 5, the pulse power supply is powered on, and the numerical control system controls the electrolytic machining electrode to rotate and adjust according to the machining trajectory, so that the electrolytic machining electrode always faces the machining contour surface, and the electrolytic machining electrode performs electrolytic machining to remove the recast layer along the closed contour trajectory. During the machining process, the electrolyte ejected by the insulating jet electrode always flushes toward the contour surface facing the machining contour, so that the electrolyte in the closed contour area of the workpiece generates eddy currents, thereby realizing rapid renewal of the electrolyte and rapid discharge of the electrolytic products;

Step 6. When the CNC system controls the electrolytic machining electrode to return to the initial machining position, the single machining stroke ends, and secondary or multiple strokes can be performed according to the machining accuracy and surface roughness requirements.

Compared with the prior art, the present invention has the following beneficial effects:

1. The functionality of the electrolytic machining electrode is strong. The distance measuring electrode can accurately control the micro-nano-level machining gap value between the electrolytic machining electrode and the machining contour surface; the electrolytic electrode is a solid structure, which can significantly increase the current density in the machining area compared with the hollow structure under the premise of determining the material, increase the removal amount and thus improve the machining efficiency; the insulating jet electrode can achieve the electric field shielding effect on the electrolytic electrode machining area, reduce the stray corrosion of the contours of the processed area and the unprocessed area, and at the same time, the jet electrolyte in the insulating jet electrode always flushes toward the contour surface in the direction opposite to the processed contour, which can form a high-speed eddy current inside the closed contour, and realize the rapid renewal flow of the electrolyte and the rapid discharge of the electrolytic machining products.

2. Precise and controllable removal thickness of the recast layer and the base material of the recast layer. Through the metallographic sample preparation method, the thickness of the recast layer of the straight-grained surface component to be processed can be accurately obtained. By controlling the precise machining gap between the electrolytic machining electrode and the machining contour surface, combined with the matching combination of machining parameters, the precise removal of the micron-level recast layer and the precise control of the removal thickness of the base material under the recast layer can be achieved.

3. Removal accuracy, surface roughness and removal efficiency are controllable. The current density in the processing area can be increased by changing the material of the electrolytic machining electrode, thereby adjusting the processing efficiency and electric field uniformity; the uniformity of the flow field can be controlled by optimizing the arrangement of the jet holes or jet slits on the side wall of the insulating jet electrode, thereby improving the current density uniformity in the processing area and adjusting the processing accuracy and surface roughness; by carrying out the selection of electrolytic machining electrode material and diameter, specific adjustment of the processing gap, and optimizing the matching of electrical parameters, electrolyte parameters, and jet parameters, the removal of different metal materials and thickness recast layers can be achieved, and the processing requirements such as removal accuracy, surface roughness and removal efficiency can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an axonometric view of an electrolytic machining electrode according to the present invention;

FIG2 is a top view of an electrolytic machining electrode according to the present invention;

FIG3 is a cross-sectional view of an electrolytic machining electrode according to the present invention;

FIG4 is a cross-sectional view of a distance measuring electrode according to the present invention;

FIG5 is a partial enlarged view of FIG4;

FIG6 is a schematic diagram of the structure of the electrolytic machining electrode of the present invention when in use;

FIG. 7 is a top view of the electrolytic machining electrode of the present invention when in use.

In the figure: 1. workpiece; 2. electrolytic machining electrode; 21. electrolytic electrode; 22. insulated jet electrode; 221. jet structure; 23. ranging electrode; 231. retaining ring; 232. micro telescopic shaft; 233. micro touch sensor; 234. guide slide; 235. reset spring; 3. electrolyte.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Embodiment 1

Please refer to Figures 1-5. The present invention provides a technical solution: an electrolytic machining electrode for removing the recast layer of a closed contour straight surface component, the electrolytic machining electrode 2 is composed of an electrolytic electrode 21, an insulating jet electrode 22 and a ranging electrode 23, the electrolytic electrode 21 is a solid semicircular cylindrical structure, the insulating jet electrode 22 is a semicircular tubular structure, and the outer diameter of the insulating jet electrode 22 is adapted to the outer diameter of the electrolytic electrode 21, the electrolytic electrode 21 and the insulating jet electrode 22 are an integrated cylindrical structure; the circumferential outer wall of the insulating jet electrode 22 is provided with a microjet structure 221 connected to its internal cavity along its radial direction;

The ranging electrode 23 includes a semi-annular clamping ring 231, and a semi-annular groove matched with the clamping ring 231 is provided on the circumferential outer wall of the electrolysis electrode 21, and the clamping ring 231 is embedded in the semi-annular groove. The outer diameter of the clamping ring 231 is the same as that of the electrolysis electrode 21 and they are concentric with each other, and the material of the clamping ring 231 is the same as that of the electrolysis electrode 21; a plurality of guide grooves 234 are provided on the side wall of the clamping ring 231 along its radial direction, and a micro-telescopic shaft 232 is slidably nested in the guide grooves 234, and a shaft shoulder is provided at the inner end of the micro-telescopic shaft 232, and a reset spring 235 is nested at the inner end of the micro-telescopic shaft 232; a micro-touch sensor 233 is provided at the telescopic end of the micro-telescopic shaft 232.

Furthermore, the micro jet structure 221 is a micro jet hole or a micro slit structure, and the micro jet structure 221 may also be other forms of micro jet structures.

Working principle:

The CNC system is used to control the movement of the electrolytic machining electrode 2 and to make the micro-touch sensor 233 on the micro-telescopic shaft 232 contact with the machining contour surface, thereby determining the electrolytic machining gap between the electrolytic machining electrode 2 and the machining contour surface, and the CNC system is used to control the electrolytic machining electrode 2 to move toward the machining contour surface to accurately adjust the electrolytic machining gap, and the electrolytic electrode 21 of the electrolytic machining electrode 2 is used to electrolytically cut the recast layer on the machining contour surface; an electrolyte channel is formed between the insulating jet electrode 22 of the semicircular tubular structure and the electrolytic electrode 21, and when the electrolytic machining electrode 2 is electrolytically cut, the electrolyte 3 flowing into the electrolyte channel is ejected through the micro-jet structure 221 and flushes the contour surface in the direction opposite to the machined contour, so that the electrolyte 3 in the machining area generates eddy currents, thereby realizing rapid renewal flow of the electrolyte 3 and rapid discharge of the electrolytic machining products.

The electrolytic machining electrode disclosed in this embodiment electrolytically cuts the recast layer on the machining contour surface through the electrolytic electrode 21 of the electrolytic machining electrode 2; the distance measuring electrode 23 and the numerical control system can accurately adjust the electrolytic machining gap between the electrolytic machining electrode 2 and the machining contour surface, so as to accurately control the accuracy, surface roughness and removal efficiency of the electrolytic machining electrode 2 in removing the recast layer on the machining contour surface; the electrolytic electrode 21 is a solid semicircular cylindrical structure, which can significantly increase the current density in the machining area and increase the amount of recast layer removal compared to the hollow structure under the premise of determining the material, thereby further improving the machining efficiency.

Embodiment 2

Referring to FIGS. 1-7 , the present invention provides a technical solution: a method for removing the recast layer of a closed contour straight surface component using the above-mentioned electrolytic machining electrode, comprising the following steps:

Step 1: Select a closed contour straight surface component with a recast layer on the surface of the same batch as a sample of the workpiece 1 to be processed, and use a metallographic sample preparation method to obtain a cross section of the recast layer to obtain the thickness value of the recast layer of the workpiece 1;

Step 2: After the electrolytic machining electrode 2 and the workpiece 1 are clamped, the electrolytic electrode 21 is electrically connected to the negative electrode of the pulse power supply, the workpiece 1 is electrically connected to the positive electrode of the pulse power supply, and the electrolyte 3 is injected into the electrolyte tank to immerse the machining area; the numerical control system drives the electrolytic machining electrode 2 to move to the contour surface to be machined of the workpiece 1, and drives the electrolytic machining electrode 2 to rotate so that the electrolytic electrode 21 is facing the contour surface to be machined, and the numerical control system controls the electrolyte circulation system to inject the electrolyte 3 into the port of the insulating jet electrode 22, and the electrolyte 3 in the insulating jet electrode 22 is ejected out through the jet structure 221;

Step 3: The numerical control system controls the electrolytic machining electrode 2 to approach the contour surface to be machined until the micro-touch sensor 233 of the distance measuring electrode 23 touches the contour surface, and the micro-touch sensor 233 transmits a signal to the numerical control system. Since the initial distance between the micro-touch sensor 233 and the electrolytic electrode 21 is known, the initial machining gap value between the electrolytic machining electrode 2 and the contour surface to be machined at this time can be displayed by the numerical control system;

Step 4: The numerical control system controls the electrolytic machining electrode 2 to continuously feed the contour surface to be machined, and adjusts the machining gap value between the electrolytic machining electrode 2 and the machining contour surface by contracting the micro-telescopic shaft 232 until the machining gap required for machining is reached;

Step 5, the pulse power supply is powered on, and the numerical control system controls the electrolytic machining electrode 2 to rotate and adjust according to the machining trajectory, so that the electrolytic machining electrode 21 is always facing the machining contour surface, and the electrolytic machining electrode 2 performs electrolytic machining to remove the recast layer along the closed contour trajectory. During the machining process, the electrolyte 3 ejected by the insulating jet electrode 22 is always flushed toward the contour surface facing the machining contour, so that the electrolyte 3 in the closed contour area of the workpiece 1 generates eddy currents, thereby realizing rapid renewal of the electrolyte and rapid discharge of the electrolytic products;

Step 6: When the numerical control system controls the electrolytic machining electrode 2 to return to the initial machining position, the single machining stroke ends, and secondary stroke machining or multiple stroke machining can be performed according to the machining accuracy and machining surface roughness requirements.

By carrying out the selection of material and diameter of electrolytic machining electrode 2, specific adjustment of machining gap and optimization matching of electrical parameters, electrolyte parameters and jet parameters, the removal of recast layers of different metal materials and thicknesses can be achieved, and the machining requirements such as removal accuracy, removal of surface roughness and removal efficiency can be met.

The present embodiment discloses a method for removing the recast layer of a closed contour straight surface component by an electrolytic machining electrode. When the electrolytic machining electrode 2 removes the recast layer of the closed contour straight surface component, the thickness of the recast layer of the straight surface component to be machined can be accurately obtained by a metallographic sample preparation method. By controlling the precise machining gap between the electrolytic machining electrode 2 and the machining contour surface, combined with a matching combination of machining parameters, the precise removal of the recast layer and the precise control of the thickness of the base material under the recast layer can be achieved, thereby improving the precision of removing the recast layer, removing the surface roughness, and removing efficiency.

By spraying the electrolyte 3 through the micro jet structure 221, the rapid renewal flow of the electrolyte 3 and the rapid discharge of the electrolytic processing products can be achieved, further improving the removal efficiency of the recast layer;

The insulating jet electrode 22 can achieve the electric field shielding effect on the processing area of the electrolytic electrode 21, reduce the stray corrosion on the contours of the processed area and the unprocessed area, and further improve the accuracy of removing the recast layer;

The electrolytic electrode 21 is a solid semicircular cylindrical structure, which can significantly increase the current density in the processing area and increase the amount of recast layer removed compared to a hollow structure under the premise of determining the material, thereby further improving the processing efficiency.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. An electrolytic machining removal electrode for a closed contour straight surface component recast layer, the electrolytic machining electrode (2) being composed of an electrolytic electrode (21), an insulating jet electrode (22) and a distance measuring electrode (23), characterized in that: the electrolytic electrode (21) is a solid semicircular cylindrical structure, the insulating jet electrode (22) is a semicircular tubular structure, and the outer diameter of the insulating jet electrode (22) matches the outer diameter of the electrolytic electrode (21), and the electrolytic electrode (21) and the insulating jet electrode (22) are an integrated cylindrical structure; the distance measuring electrode (23) comprises a plurality of micro telescopic shafts (232) arranged on the electrolytic electrode (21), the micro telescopic shafts (232) being arranged along the radial direction of the electrolytic electrode (21), and the telescopic ends of the micro telescopic shafts (232) being provided with micro touch sensors (233); and a micro jet structure (221) communicating with an internal cavity of the insulating jet electrode (22) is provided on the circumferential outer wall of the insulating jet electrode (22) along its radial direction. 2. According to claim 1, a closed contour straight surface component recast layer electrolytic machining removal electrode is characterized in that: the distance measuring electrode (23) includes a semi-annular clamping ring (231), and the circumferential outer wall of the electrolytic electrode (21) is provided with a semi-annular groove adapted to the clamping ring (231), and the clamping ring (231) is embedded in the semi-annular groove. The outer diameter of the clamping ring (231) and the electrolytic electrode (21) are the same and concentric with each other, and the material of the clamping ring (231) and the electrolytic electrode (21) are the same; the micro-telescopic shaft (232) is arranged on the clamping ring (231). 3. According to claim 2, a closed contour straight surface component recast layer electrolytic machining electrode removal is characterized in that: a plurality of guide grooves (234) adapted to the structure of the micro-telescopic shaft (232) are opened on the circumferential outer wall of the retaining ring (231) along its radial direction, the micro-telescopic shaft (232) is nested in the guide grooves (234), the inner end of the micro-telescopic shaft (232) is provided with a shoulder, and the inner end of the micro-telescopic shaft (232) is nested with a return spring (235). 4. The closed contour straight surface component recast layer electrolytic machining electrode removal method according to claim 1, characterized in that: the micro jet structure (221) is a micro jet hole or a micro slit structure. 5. A method for removing the recast layer of a closed contour straight surface component using the electrolytic machining electrode according to any one of claims 1 to 4, characterized in that it comprises the following steps: Step 1: Select a closed contour straight surface component with a recast layer on the surface of the same batch as a sample of the workpiece (1) to be processed, and use a metallographic sample preparation method to obtain a cross section of the recast layer to obtain the thickness value of the recast layer of the workpiece (1); Step 2: After the electrolytic machining electrode (2) and the workpiece (1) are clamped, the electrolytic electrode (21) is electrically connected to the negative electrode of the pulse power supply, the workpiece (1) is electrically connected to the positive electrode of the pulse power supply, and the electrolyte (3) is injected into the electrolyte tank to immerse the machining area; the numerical control system drives the electrolytic machining electrode (2) to move to the contour surface to be machined of the workpiece (1), and drives the electrolytic machining electrode (2) to rotate so that the electrolytic electrode (21) is facing the contour surface to be machined, and the numerical control system controls the electrolyte circulation system to inject the electrolyte (3) into the port of the insulating jet electrode (22), and the electrolyte (3) in the insulating jet electrode (22) is ejected out through the jet structure (221); Step 3: The numerical control system controls the electrolytic machining electrode (2) to approach the contour surface to be machined until the micro-touch sensor (233) of the distance measuring electrode (23) touches the contour surface, and the micro-touch sensor (233) transmits a signal to the numerical control system. Since the initial distance between the micro-touch sensor (233) and the electrolytic electrode (21) is known, the initial machining gap value between the electrolytic machining electrode (2) and the contour surface to be machined can be displayed by the numerical control system at this time; Step 4: The numerical control system controls the electrolytic machining electrode (2) to continuously feed the contour surface to be machined, and adjusts the machining gap value between the electrolytic machining electrode (2) and the machining contour surface by contracting the micro-telescopic shaft (232) until the machining gap required for machining is reached; Step 5: Turn on the pulse power supply, and the numerical control system controls the electrolytic machining electrode (2) to rotate and adjust according to the machining trajectory, so that the electrolytic machining electrode (21) always faces the machining contour surface, and the electrolytic machining electrode (2) removes the recast layer along the closed contour trajectory. During the machining process, the electrolyte (3) ejected by the insulating jet electrode (22) always flushes the contour surface in the direction facing the machining contour, so that the electrolyte (3) in the closed contour area of the workpiece (1) generates eddy currents, thereby realizing rapid renewal of the electrolyte and rapid discharge of electrolytic products. Step 6: When the CNC system controls the electrolytic machining electrode (2) to return to the initial machining position, the single machining stroke ends, and secondary or multiple strokes can be performed according to the machining accuracy and machining surface roughness requirements.