An assembled electrode for machining annular groove and annular groove machining method

Abstract

The present invention relates to an assembled electrode for machining annular grooves and an annular groove machining method, which belongs to the technical field of ultra-slender pipe machining, and solves the problem that it is difficult to realize high-precision machining of annular grooves on ultra-slender thin-walled pipes in the prior art. The electrode includes a conductive part and a discharge part electrically connected to the conductive part, wherein the discharge part is sleeved on the workpiece to be machined and moves eccentrically around the workpiece to be machined to realize the electric spark machining of the annular groove of the workpiece to be machined; wherein the discharge end of the discharge part matches the shape of the annular groove, and the discharge part and the conductive part are detachably connected. High-precision machining of annular grooves of ultra-slender thin-walled pipes is realized, and the machining can be completed in one go, and the machining efficiency is significantly improved.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-slender pipe processing, and in particular to an assembled electrode for processing annular grooves and an annular groove processing method. Background Art

[0002] Annular grooves need to be processed on some ultra-slender aircraft products. Due to the small diameter and thin wall thickness of ultra-slender aircraft products, the size of the annular grooves processed on them is smaller. For aircraft products where size control is crucial, the machining accuracy requirements of the annular grooves put forward higher requirements on their processing methods.

[0003] It is difficult to meet the machining accuracy requirements of the annular groove by using traditional turning methods. This is because the clamping of parts and the application of cutting force in turning will inevitably affect the machining accuracy of the annular groove.

[0004] Therefore, in order to meet the processing needs of annular grooves on ultra-slender aircraft products, it is necessary to explore new annular groove processing devices. Summary of the invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide an assembled electrode for machining annular grooves and an annular groove machining method, so as to solve the problem that it is difficult to achieve high-precision machining of annular grooves on ultra-slender thin-walled tubes.

[0006] On the one hand, an embodiment of the present invention provides an assembled electrode for machining an annular groove, comprising a conductive member and a discharge member electrically connected to the conductive member, wherein the discharge member is sleeved on a workpiece to be machined and moves eccentrically around the workpiece to be machined to realize electric spark machining of the annular groove of the workpiece to be machined;

[0007] Wherein, the discharge end of the discharge member matches the shape of the annular groove, and the discharge member is detachably connected to the conductive member.

[0008] Based on the further improvement of the above processing device, the conductive member includes a conductive rod, one end of which is a conductive end and is clamped on a universally adjustable clamp, and the other end of which is electrically connected to the discharge member.

[0009] Based on the further improvement of the above processing device, the electrode includes a plurality of limit plates and clamping members for fixing the limit plates, and the plurality of limit plates surround a clamping space for fixing and connecting one end of the conductive rod and the discharge member.

[0010] Based on the further improvement of the above processing device, the discharge member is a circular ring structure, one end of the conductive rod is provided with a step hole coaxial with the discharge member, and the discharge member is detachably coaxially installed in the step hole of the conductive rod.

[0011] Based on the further improvement of the above processing device, the outer circular end of the discharge member is the mounting end, one end of the conductive rod is a circular ring-shaped end, and the circular ring-shaped end is provided with a stepped through-hole-shaped groove for placing the mounting end, the mounting end is stuck in the groove, and the discharge member is electrically connected to the conductive rod through its mounting end;

[0012] Wherein, a circular ring-shaped limiting plate is also provided on the circular ring-shaped end of the conductive rod, and the circular ring-shaped limiting plate is fixedly mounted on the conductive rod by bolts to press the mounting end of the discharge member into the groove.

[0013] Based on the further improvement of the above processing device, the discharge member is a continuous annular structure, and the inner diameter of the discharge member of the annular structure is smaller than the inner diameter of the annular end of the conductive rod.

[0014] Based on the further improvement of the above processing device, the discharge member includes a plurality of fan-shaped discharge portions, and the plurality of fan-shaped discharge portions form the annular discharge member;

[0015] Wherein, a plurality of the fan-shaped discharge portions are electrically connected;

[0016] The inner diameter of the discharge member is smaller than the inner diameter of the annular end of the conductive rod.

[0017] Based on the further improvement of the above processing device, the annular limiting plate includes a plurality of sector-shaped limiting plates, and the plurality of sector-shaped limiting plates form the annular limiting plate;

[0018] The plurality of fan-shaped limiting plates are respectively used to press the plurality of fan-shaped discharge parts onto the annular ends of the conductive rods. The discharge part comprises a plurality of electric spark machining points arranged circumferentially around the workpiece to be machined;

[0019] Wherein, during the process of EDM machining by eccentric motion of the discharge member around the workpiece to be machined, the same EDM machining point includes a working state and a non-working state;

[0020] The machining of the annular groove on the surface to be machined is achieved through the working state of a plurality of electrospark machining points arranged circumferentially around the workpiece to be machined.

[0021] On the one hand, an embodiment of the present invention further provides a method for machining an annular groove, comprising performing electric spark machining on the annular groove of a workpiece using the electrode described above.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] 1. The discharge part and the conductive part of the tool electrode of the present invention are detachably connected. After electrospark machining, there is no need to remove the entire tool electrode from the universal adjustable clamp for replacement. The damaged tool electrode can be replaced by replacing the discharge part. In this way, the tool electrode can be clamped without adjusting the universal adjustable clamp again, which makes replacement convenient.

[0024] 2. The discharge component of the present invention is composed of a plurality of fan-shaped discharge parts. After the processing is completed, the partially damaged fan-shaped discharge parts can be replaced, thereby avoiding the increased processing cost due to the overall replacement of the discharge component; at the same time, for the processing of annular grooves with various shapes, it is not necessary to design and process the entire tool electrode to adapt to the annular groove. The electric spark processing of annular grooves with various shapes can be achieved by replacing some of the fan-shaped discharge parts, thereby reducing the processing cost of the annular grooves.

[0025] 3. The discharge end of the tool electrode of the present invention is annular, and is sleeved on the outer end face of the ultra-slender stainless steel tube to make eccentric movement. During this process, the distance between the end face of the discharge end and the end face to be processed of the ultra-slender stainless steel tube is constantly changing, the closer distance is the working end, and the farther distance is the non-working end, so that the outer end face of the ultra-slender stainless steel tube is electrospark processed by the working end; that is, along the processing direction, the position of the working end is constantly changing on the inner circular end face of the discharge end, that is, when the inner circular end face of the discharge end is close to the outer end face of the ultra-slender stainless steel tube, the end face of the discharge end is the working end, and when the end face is far away from the outer end face of the ultra-slender stainless steel tube, the end face is transformed into the non-working end, realizing the dynamic transformation between the working end and the non-working end, thereby avoiding the working end of the tool electrode from being in a continuous processing state, greatly reducing the loss of the working end of the tool electrode, achieving the tool electrode loss ≤1%, and then reducing the deformation of the working end face of the tool electrode, thereby improving the accuracy of processing the fracture groove of the ultra-slender stainless steel tube.

[0026] 4. The discharge end of the tool electrode of the present invention is sleeved on the ultra-slender stainless steel tube for eccentric movement. During processing, the distance between the discharge end and the ultra-slender stainless steel tube changes from large to small and then from small to large. In the process of the distance changing from large to small, metal debris will be generated between the discharge end and the stainless steel tube. At this time, part of the metal debris will be discharged through the processing gap with the working fluid. In the process of the distance changing from small to large, the distance between the discharge end and the stainless steel tube can be increased by nearly 200 times, which significantly improves the efficiency of discharging metal debris, thereby avoiding the accumulation of metal debris at the discharge end due to untimely discharge, thereby reducing the loss of the tool electrode, and avoiding the risk of short circuit caused by the tool electrode being directly connected to the stainless steel tube through the metal debris.

[0027] 5. By putting the discharge end of the tool electrode on the ultra-slender stainless steel tube for eccentric movement, metal debris can be efficiently discharged, thereby realizing EDM with a smaller machining gap. In this way, the machining current and voltage values ​​can be reduced, the machining cost is reduced, and a fracture groove with low surface roughness can be obtained.

[0028] 6. By adjusting the value of the unilateral feed amount, the fracture grooves with different wall thicknesses can be processed. By adjusting the shape of the discharge end of the tool electrode, the size processing of different bevel angles α can be achieved, laying the foundation for rapid production and mass production of products.

[0029] 7. The tool electrode of the present invention can complete the processing of the fracture groove of the ultra-slender stainless steel tube by eccentrically moving around the central axis of the inner cavity of the ultra-slender stainless steel tube for one circle, achieving one-time processing and significantly improving the processing efficiency.

[0030] 8. The present invention abandons the traditional turning method for ultra-thin stainless steel tubes, and uses the working end of the tool electrode to discharge and etch away the metal on the surface of the ultra-thin stainless steel tube to perform fracture groove processing. That is, during the processing, the tool electrode does not contact the surface of the ultra-thin stainless steel tube, and will not cause it to deform, thereby overcoming the problem of damage to the ultra-thin stainless steel tube caused by cutting force.

[0031] 9. The present invention utilizes the discharge end of the tool electrode to eccentrically move around the central axis of the inner cavity of the ultra-slender stainless steel tube to process the fracture groove of the ultra-slender stainless steel tube. That is, during the processing, the ultra-slender stainless steel does not need to be rotated to realize the processing of a ring-shaped fracture groove on its outer surface, thus overcoming the problem of the coaxiality of the ultra-slender stainless steel tube deteriorating during the rotation process and affecting the processing accuracy.

[0032] 10. By eccentrically moving the tool electrode around the central axis of the inner cavity of the stainless steel tube, the same unilateral feed amount can be achieved on the end face of each discharge end, ensuring the consistency of the processing depth of the fracture groove, thereby improving the processing accuracy of the fracture groove.

[0033] 11. The present invention adjusts the inclination angle of the tool electrode on the horizontal plane through the first adjustment part of the universal adjustable clamp; determines the inclination angle of the tool electrode on the YZ plane of the machine tool according to the detection value of the micrometer and the time and speed of the movement of the micrometer, compares the angle scale value on the first connector, and pushes the angle adjustment bolt to the corresponding scale, so as to achieve high-precision adjustment of the inclination angle of the tool electrode on the YZ plane of the machine tool, thereby realizing the alignment of the tool electrode, which is easy to operate and improves the processing efficiency and accuracy.

[0034] 12. During processing, it is only necessary to place the ultra-slender stainless steel tube in the V-shaped groove on the equal height positioning block and the auxiliary bearing block, and use the clamping plate to limit the upper surface of the ultra-slender stainless steel tube, so as to realize the clamping and positioning of the ultra-slender stainless steel tube. The clamping is convenient and can ensure the stability of the ultra-slender stainless steel tube during the processing.

[0035] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0037] Figure 1 It is a schematic diagram of the structure of the cooperation among the limiting member, the limiting plate and the conductive member in the present invention;

[0038] Figure 2 It is a cross-sectional structural schematic diagram of the cooperation between the limiting member, the limiting plate and the conductive member in the present invention;

[0039] Figure 3 It is a schematic diagram of the structure of the annular limiting plate, the annular discharge member and the conductive member in cooperation with each other according to the present invention;

[0040] Figure 4 It is a structural schematic diagram of the annular limiting plate, the annular discharge member, and the conductive member of the present invention;

[0041] Figure 5 for Figure 3 Schematic diagram of the cross section at AA in the middle;

[0042] Figure 6 It is a schematic diagram of the structure of the fan-shaped limiting plate, the fan-shaped discharge part and the conductive member in the present invention;

[0043] Figure 7 It is a schematic structural diagram of the fan-shaped limiting plate, the fan-shaped discharge portion, and the conductive member of the present invention;

[0044] Figure 8 It is a structural schematic diagram when the center line of the discharge end of the tool electrode of the present invention coincides with the center axis of the inner cavity of the stainless steel tube;

[0045] Fig. 9 It is a structural schematic diagram of the tool electrode of the present invention when the center line deviates from the center axis of the inner cavity of the stainless steel tube;

[0046] Fig.10 It is a schematic diagram of the motion trajectory of the center point O2 of the discharge end when the discharge end of the tool electrode in the present invention moves eccentrically around the central axis of the inner cavity of the stainless steel tube;

[0047] Fig.11 It is a schematic diagram of the motion trajectory of any point O3 on the discharge end when the discharge end of the tool electrode in the present invention moves eccentrically around the central axis of the inner cavity of the stainless steel tube;

[0048] Fig.12 It is a schematic diagram of the overall structure of the universally adjustable clamp of the present invention;

[0049] Fig.13 is a cross-sectional schematic diagram of the universally adjustable clamp of the present invention;

[0050] Fig.14 It is a schematic diagram of the matching structure of the transfer adjustment bolt and the first connecting body of the present invention;

[0051] Fig.15 This is a schematic diagram of the structure of the stainless steel pipe breaking groove in the present invention;

[0052] Fig.16 This is a schematic diagram of the matching structure of the load-bearing assembly and the stainless steel pipe of the present invention;

[0053] Fig.17 It is a physical schematic diagram of the stainless steel pipe after the broken groove is processed in the present invention.

[0054] Reference numerals:

[0055] 1- tool electrode; 101- discharge end; 102- working end; 103- non-working end; 104- conductive end; 2- transmission rod; 3- equal height positioning block; 4- auxiliary bearing block; 5- clamping plate; 6- stainless steel pipe; 601- breaking groove; 7- machining direction; 8- eccentric movement direction; 9- machine tool worktable; 10- reference seat; 11- clamp seat; 12- fastening screw; 13- first fixing seat; 14- second fixing seat; 15- vertical screw; 16- insulation plate; 17- fixture head; 18- first connector; 19- second connector Connector; 20-rotating body; 21-rotation angle adjustment bolt; 22-notch; 23-moving direction of the micrometer on the discharge end face of the tool electrode along the Z-axis direction of the machine tool; 24-moving direction of the micrometer on the discharge end face of the tool electrode along the Y-axis direction of the machine tool; 25-conductive member; 26-circular ring-shaped discharge member; 27-limiting plate; 28-clamping member; 29-circular ring-shaped limiting plate; 30-fan-shaped discharge part; 31-fan-shaped limiting plate; 32-groove; H1-wall thickness of stainless steel pipe; H2-wall thickness of breaking groove; α-bevel angle of breaking groove; S 11 , S 12 , S 13 , S 14-The actual margin gap value between the four points selected on the circular working end of the tool electrode and the outer end surface of the stainless steel tube; S2-machining gap; O1-discharge end center point; O2-stainless steel tube inner cavity center point; O3-point selected on the discharge end. DETAILED DESCRIPTION

[0056] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0057] Generally, the ratio of diameter to length reaches 1:100-150, which is an ultra-slender shaft. For example, the outer diameter of a stainless steel pipe used in a certain aviation product is 2mm, the inner diameter is 1mm, and the length is 1-1.2m. The ratio of the outer diameter to length of the stainless steel pipe is 1:500-600, which is an ultra-slender stainless steel pipe. During processing, it is generally necessary to process a V-groove on the ultra-slender steel pipe. The V-groove is a breaking groove, which is used to separate the guidance system of the aviation product from the fairing body of the product when the product reaches the predetermined height and position.

[0058] Since the diameter of the ultra-thin stainless steel tube is small and the wall thickness is thin, and the wall thickness at the breaking groove position is even thinner, such as the wall thickness at the breaking groove position is 0.3±0.05mm, its important dimensions cannot be obtained by direct measurement; when processing the breaking groove at a certain position of the ultra-thin stainless steel tube, it is difficult to ensure the wall thickness size at the breaking groove position by using the traditional turning processing method. This is because the centrifugal force causing the workpiece to rotate during the rotation process will be greater due to the excessive length, the coaxiality of the workpiece will be worse, and the cutting force generated will easily cause the ultra-thin stainless steel tube to deform.

[0059] If the existing electrospark machining device is used to machine the fracture groove of an ultra-slender stainless steel tube, it is necessary to rotate the ultra-slender stainless steel tube, and then use the tool electrode to continuously advance on the surface of the ultra-slender stainless steel tube for machining. However, since the ultra-slender stainless steel tube is relatively long, the centrifugal force causing the workpiece to rotate during the rotation process will be greater, and the coaxiality of the workpiece will be worse, which will also make it difficult to ensure the wall thickness size of the fracture groove position; and in the process of machining, part of the total energy is released to the tool electrode, which will cause tool loss, and the shape of the lost tool electrode will eventually be copied on the ultra-slender stainless steel tube, seriously affecting the machining accuracy of the fracture groove.

[0060] In order to solve the above problems, the present invention provides an assembled electrode for machining annular grooves, comprising a conductive member 25 and a discharge member electrically connected to the conductive member 25, wherein the discharge member is sleeved on a workpiece to be machined and moves eccentrically around the workpiece to be machined to realize electric spark machining of the annular groove of the workpiece to be machined;

[0061] The discharge end of the discharge member matches the shape of the annular groove, and the discharge member is detachably connected to the conductive member.

[0062] Specifically, the conductive member 25 includes a conductive rod, one end of which is a conductive end and is clamped on a universally adjustable clamp, and the other end of which is electrically connected to the discharge member.

[0063] That is to say, the tool electrode 1 is no longer an integral structure, and the discharge part and the conductive part 25 are detachably connected. After the discharge part of the electrode moves eccentrically around the workpiece to be processed for electrospark machining, the damaged discharge part can be replaced separately to avoid affecting the machining accuracy.

[0064] In a possible implementation, Figure 1-2 As shown, the electrode includes a plurality of limit plates 27 and a clamping member 28 for fixing the limit plates 27. The plurality of limit plates 27 surround a clamping space for fixing and connecting one end of the conductive rod and the discharge member. The discharge member and one end of the conductive rod are respectively inserted into the clamping space, and the discharge member and one end of the conductive rod are respectively fastened in the clamping space by the clamping member 28, so that the discharge member is connected to the conductive member 25. After the electrospark machining is completed, the clamping member 28 is removed to replace the discharge member.

[0065] Among them, four limit plates 27 are provided, and the clamping member 28 can be two arc-shaped plates, which are attached to the outside of the four limit plates 27, and the two arc-shaped plates are fastened to each other by bolts, so that pressure is applied to the four limit plates 27, so that the four limit plates 27 are squeezed toward the discharge member and the conductive rod, thereby achieving the discharge member and the conductive rod being fastened in the clamping space. The clamping member 28 can also be other shapes, as long as the four limit plates 27 can squeeze the conductive rod.

[0066] The discharge member may be a circular ring structure, such as Figure 2 As shown, a connecting portion is provided at the upper end of the annular discharge member, and the connecting portion is used to be placed in the clamping space and electrically connected to the conductive rod.

[0067] In a possible implementation, Figure 3-5 As shown, the discharge member is a circular ring structure, and the end of the conductive rod electrically connected to the discharge member is provided with a step hole coaxial with the discharge member, and the discharge member is detachably coaxially installed in the step hole of the conductive rod.

[0068] The outer cylindrical surface of the discharge member is gap-matched with the inner wall of the step hole, and one end surface of the discharge member abuts against the step surface in the step hole, thereby realizing axial limitation of the discharge member in the step hole of the conductive rod.

[0069] The conductive rod also includes an annular stopper plate 29, which is used to press the discharge member 26 into the step hole of the conductive rod. Specifically, the annular stopper plate 29 is provided with a through hole coaxial with the discharge member 26, and is fixedly mounted on the conductive rod outside the step hole by bolts. In this way, before processing, the workpiece to be processed sequentially passes through part of the step hole, the center hole of the annular ring of the discharge member 26, and the through hole of the annular stopper plate, so that the discharge member is sleeved outside the workpiece to be processed. After processing is completed, the annular stopper plate 29 is removed to replace the discharge member.

[0070] In a specific embodiment, the end of the conductive rod electrically connected to the discharge member is an annular structure, the annular center hole is a stepped through-hole-shaped groove, the outer circular end of the discharge member is a mounting end, a groove 32 for placing the mounting end is provided on the annular end of the conductive rod, the mounting end is stuck in the groove 32, and the discharge member is electrically connected to the conductive rod through its mounting end; an annular stop plate 29 is also provided on the annular end of the conductive rod, and the annular stop plate 29 is fixedly installed on the conductive rod by bolts to press the mounting end of the annular discharge member 26 into the groove 32. In this way, after the processing is completed, the annular stop plate 29 can be removed to replace the discharge member.

[0071] In a possible implementation, Figure 6-7 As shown, the discharge member includes a plurality of fan-shaped discharge parts 30, and the plurality of fan-shaped discharge parts 30 form the annular discharge member 26; the plurality of fan-shaped discharge parts 30 are electrically connected; the annular limiting plate 29 includes a plurality of fan-shaped limiting plates 31, and the plurality of fan-shaped limiting plates 31 form the annular limiting plate 29; the plurality of fan-shaped limiting plates 31 respectively press the plurality of fan-shaped discharge parts 30 against the step holes of the conductive rod. In this way, after the processing is completed, some of the fan-shaped discharge parts 30 can be replaced separately to realize the replacement of the discharge member; wherein, during the processing, the inner arc surface of the fan-shaped discharge part 30 faces the surface to be processed, and for annular grooves of different required shapes and sizes, the shape of the inner arc surface of the fan-shaped discharge part 30 can be changed to realize the processing of annular grooves of different shapes and sizes.

[0072] Exemplarily, four fan-shaped discharge portions 30 and four fan-shaped limiting plates 31 are provided.

[0073] Compared with the prior art, the discharge part and the conductive part of the tool electrode 1 of the present invention are detachably connected. After electrospark machining, there is no need to remove the entire tool electrode 1 from the universal adjustable clamp for replacement. Only the discharge part needs to be replaced to replace the damaged tool electrode 1. In this way, the tool electrode can be clamped without adjusting the universal adjustable clamp again, which is convenient for replacement. In addition, the electrode material of the conductive part reduces the cost of electrospark machining.

[0074] Wherein, the inner diameter of the annular discharge member is smaller than the inner diameter of the step hole of the conductive rod.

[0075] Specifically, the discharge member and the conductive member are connected to form a complete tool electrode 1. At this time, one end of the tool electrode 1 is a discharge end 101, and the discharge end includes a plurality of electric spark machining points arranged circumferentially around the workpiece to be machined. The same electric spark machining point includes a working state and a non-working state.

[0076] When the distance between the EDM point and the surface to be machined is greater than a threshold, the EDM point is in a non-working state; when the distance between the EDM point and the surface to be machined is less than or equal to a threshold, the EDM point is in a working state; the above threshold is a discharge distance between the EDM point and the surface to be machined that meets the machining requirements, and illustratively, the distance is 0-50 μm.

[0077] It can be understood that the discharge end 101 includes a plurality of electrospark machining points arranged circumferentially around the workpiece to be machined. The plurality of electrospark machining points arranged circumferentially around the workpiece to be machined can be continuously and uninterruptedly distributed around the workpiece to be machined, or can be discontinuously distributed around the workpiece to be machined, so as to achieve continuous machining and forming of the V-groove on the machined surface.

[0078] In a possible embodiment, one end of the tool electrode 1 is in a circular ring shape, that is, a plurality of electrospark machining points arranged circumferentially around the workpiece to be machined form a continuous circular ring, and the inner circular end of the circular ring matches the shape of the V-groove, that is, the inner circular end is convex, and the V-groove is concave, and the cross-sectional size of the convex shape is the same as the cross-sectional shape of the concave groove; the other end of the tool electrode 1 is a conductive end 104, which is electrically connected to an output end of a power supply device arranged on the machine tool to introduce current and transmit the current to the inner circular end. At this time, the inner circular end is a discharge end 101, so as to realize the processing of the V-groove on the surface to be machined through the working state of the plurality of electrospark machining points arranged circumferentially around the workpiece to be machined of the discharge end 101.

[0079] In a possible implementation, the discharge end is a rigid structure, and the discharge end 101 is sleeved on the outer end face of the stainless steel tube 6; during processing, the stainless steel tube 6 is electrically connected to the other output end of the power supply device, and the tool electrode 1 moves eccentrically around the central axis of the inner cavity of the stainless steel tube 6; wherein, during the eccentric movement of the tool electrode 1, the distance between the inner circular end face of the discharge end 101 and the end face to be processed of the stainless steel tube 6 is constantly changing; when the distance between the EDM point and the surface to be processed is greater than a threshold value, the EDM point is in a non-working state, at which time, the EDM point is a non-working end 103; when the distance between the EDM point and the surface to be processed is less than or equal to a threshold value, the EDM point is in a non-working state, at which time, the EDM point is a non-working end 103; When the threshold value is reached, the EDM point is in the working state. At this time, the EDM point is the working end 102, so that the transition between the working state and the non-working state is realized at the same EDM point. The working states of all the EDM points jointly realize the processing of the fracture groove on the surface to be processed. That is to say, the position of the working end 102 is constantly changing in the inner circular end surface of the discharge end 101, and the circular discharge end of the tool electrode eccentrically moves around the central axis of the inner cavity of the stainless steel tube for one circle. All the working ends form a continuous annular discharge end around the circumference of the stainless steel tube, so that the discharge end 101 of the tool electrode 1 is avoided from being in a continuous processing state, thereby reducing the loss of the tool electrode 1.

[0080] In the process of eccentric movement of the tool electrode 1, the distance between the end face of the discharge end 101 and the end face to be processed of the stainless steel tube 6 is constantly changing, and the distance of 10-50 μm is in the working state, i.e., the working end 102, and the distance greater than 50 μm is in the non-working state, i.e., the non-working end 103. The processing tracks of all the working ends 102 together constitute the ultra-slender stainless steel tube breaking groove 601.

[0081] Among them, the annular discharge end 101 of the tool electrode 1 includes a plurality of working ends 102 distributed in a ring shape. When the discharge end eccentrically moves around the central axis of the inner cavity of the stainless steel tube 6 for processing, the plurality of working ends 102 are in an asynchronous and non-continuous processing state; and the processing trajectories of the plurality of working ends together constitute the fracture groove of the stainless steel tube 6.

[0082] Among them, after the tool electrode 1 moves eccentrically for one circle, all end faces of the discharge end 101 are involved in the electrospark machining, that is, all working ends 102 constitute a complete discharge end 101, and the machining trajectories of all working ends 102 together constitute the ultra-slender stainless steel pipe breaking groove 601; along the machining direction 7, the working end 102 shows a "circular motion" phenomenon on the discharge end 101, that is, at different times, the position of the working end 102 is different, thereby achieving alternating and orderly machining of all working ends 102, and the machining direction 7 is the circumferential direction around the outer end face of the stainless steel pipe 6, and the surface where the circumferential direction is located is perpendicular to the central axis of the inner cavity of the stainless steel pipe 6.

[0083] Specifically, one end of the tool electrode 1 is mounted on the machine tool through a universally adjustable fixture, and the discharge end 101 of the tool electrode 1 is sleeved on the outer end surface of the stainless steel tube 6, as shown in FIG. Figure 8 As shown, the center of the inner round end of the discharge end 101 of the tool electrode 1 coincides with the inner axis of the inner cavity of the stainless steel tube 6, and there is a margin gap between the discharge end 101 and the outer end surface of the stainless steel tube 6, that is, the diameter of the inner round end of the discharge end 101 is larger than the outer diameter of the stainless steel tube 6. For example, the diameter of the inner round end is 10-20 mm, which is 5-10 times the outer diameter of the stainless steel tube 6. In this way, during the EDM process, it is easy to determine the value of the single-side feed O1O2. During machining, the tool electrode 1 is driven to swing by the machine tool. At this time, as shown in FIG. Fig. 9 As shown, the discharge end 101 of the tool electrode 1 is in an eccentric motion state around the central axis of the inner cavity of the stainless steel tube 6.

[0084] Among them, the single-side feed amount O1O2 satisfies:

[0085] O1O2=S1+(H1-H2)-S2

[0086] Wherein, O1 represents the center point of the discharge end 101 of the tool electrode;

[0087] O2 represents the center point of the inner cavity of the stainless steel tube 6;

[0088] H1 is the wall thickness of the stainless steel tube 6;

[0089] H2 is the wall thickness of the fracture groove 601;

[0090] S2 is the machining gap, which refers to the shortest distance between the working end 102 and the end face of the stainless steel tube 601 when the tool electrode 1 moves eccentrically;

[0091] S1 is a margin gap between the discharge end 101 and the outer end surface of the stainless steel tube 6 .

[0092] Among them, S1 satisfies:

[0093]

[0094] Among them, Figure 8 As shown, S 11 , S 12 , S 13 , S 14 are actual margin gap values ​​between four points selected on the discharge end 101 of the tool electrode and the outer end surface of the stainless steel tube 6 , and the four points are evenly distributed on the discharge end 101 .

[0095] For example, S 11 , S 12 , S 13 , S 14They are 2.055mm, 2.060mm, 2.065mm and 2.050mm respectively. At this time, S1=2.058mm.

[0096] The machining gap S2 is set to 10-50 μm to meet the requirements of EDM.

[0097] Exemplarily, S2=10 μm; H1=0.5 mm, H2=0.3 mm, S1=2.058 mm, then O1O2=2.248 mm.

[0098] Among them, the automatic centering module on the machine tool can be used to measure S 11 , S 12 , S 13 , S 14 , wherein, if the four values ​​are equal, the center of the inner circular end of the discharge end 101 of the tool electrode 1 coincides with the central axis of the inner cavity of the stainless steel tube 6 .

[0099] Among them, after the center of the discharge end 101 of the tool electrode 1 is adjusted by the machine tool to coincide with the inner axis of the stainless steel tube 6, the actual measured S 11 , S 12 , S 13 , S 14 The closer the four values ​​are, the more accurate the value of S1 is, and thus the more accurate the single-side feed amount O1O2 is. In this way, during the eccentric movement of the tool electrode 1, the accuracy of the machining gap can be ensured, and then the machining depth of the working end 101 can be guaranteed to ensure the dimensional accuracy of the machined fracture groove 601.

[0100] Among them, after adjusting the center of the discharge end 101 of the tool electrode 1 to coincide with the central axis of the inner cavity of the stainless steel tube 6, the tool electrode 1 is in an eccentric motion state under the action of the machine tool, and the detailed process is shown below.

[0101] The motion trajectories of the center point O1 of the discharge end 101 of the tool electrode 1 and the center point O2 of the inner cavity of the stainless steel tube 6 are described as follows:

[0102] Move the tool electrode 1 so that O1 is away from O2. The moving distance is the same as the single-side feed amount O1O2. At this time, the distance between O1 and O2 is O1O2.

[0103] With O2 as the center and O1O2 as the radius, rotate O1 around O2. At this time, the trajectory of O1's movement is a circle, such as Fig.10 As shown, the center of the circle is O2 and the radius is O1O2;

[0104] In the process of moving O1, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel tube 6 reaches 10 μm, the power supply device is turned on to transmit a pulse voltage to the tool electrode 1 and the stainless steel tube 6, and the metal on the surface of the stainless steel tube 6 is etched at a processing speed of 0.04 g / min until the distance between O1 and O2 is O1O2, and then O1 moves in a circle around O2.

[0105] In order to further illustrate the motion trajectory of the tool electrode 1, an arbitrary point O3 on the discharge end 101 is selected and the trajectory of O3 is used for explanation as follows:

[0106] Move the tool electrode 1 so that O3 moves toward O2, and the moving distance is O1O2;

[0107] When O1 rotates around O2, at this time, if Fig.11 As shown, the trajectory of O3 is: a circle with the initial position of O3 as the center and O1O2 as the radius;

[0108] Among them, during the movement of O3, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel tube 6 reaches 10μm, the power supply device is turned on to transmit a pulse voltage to the tool electrode 1 and the stainless steel tube 6, and the metal on the surface of the stainless steel tube 6 is etched at a processing speed of 0.04g / min until the moving distance of O3 reaches O1O2, and then O3 moves in a circle with its initial position as the center.

[0109] In this way, during the eccentric movement of the tool electrode 1, the distance between the inner circular end surface of the discharge end 101 and the outer surface of the stainless steel tube 6 is constantly changing, and the distance between each part of the inner circular end surface of the discharge end 101 and the outer end surface of the stainless steel tube 6 is changed from close to far away. Then, the discharge end 101 is changed from a working state to a non-working state, that is, a dynamic transition between the working end 102 and the non-working end 103 is realized, thereby avoiding the working end 102 of the tool electrode 1 from being in a continuous processing state, and greatly reducing the loss of the working end 102 of the tool electrode 1.

[0110] There is a margin gap S1 between the discharge end 101 and the outer end surface of the stainless steel tube 601, which is used to ensure that the non-processing gap between the non-working end 103 at the discharge end 101 and the end surface of the stainless steel tube 6 is large enough, thereby ensuring that the pulse voltage released at the non-working end 103 cannot corrode the metal on the surface of the stainless steel tube 6. In this way, when the tool electrode 1 moves eccentrically, the working end 102 and the non-working end 103 can be dynamically transformed.

[0111] Among them, the conductive end of the tool electrode 1 is electrically connected to an output end of a power supply device arranged on the machine tool, and the stainless steel tube 6 is electrically connected to the other output end of the power supply device. The power supply device includes a pulse power supply, and its two output ends are respectively connected to the positive and negative poles of the pulse power supply to output a pulse voltage.

[0112] Exemplarily, during the processing, the electrical parameters satisfy:

[0113] The pulse width is 30 to 60 μs, the pulse interval is 20 to 30 μs, the average processing current is 0.8 to 2A, and the average processing voltage is 30 to 60V.

[0114] Specifically, a driving assembly is also provided to drive the tool electrode to move during processing; the driving assembly includes a transmission rod 2, one end of the transmission rod 2 is connected to the tool electrode 1 through a universally adjustable clamp, and the other end of the transmission rod 2 is installed on a machine tool. The transmission rod 2 can be controlled to swing through the machine tool, and then the transmission rod 2 drives the discharge end 101 of the tool electrode 1 to make an eccentric movement around the central axis of the inner cavity of the stainless steel tube 6.

[0115] Specifically, the transmission rod 2 swings clockwise in the swing plane ZY, which is parallel to the plane where the discharge end 101 is located, thereby realizing the eccentric movement of the discharge end of the tool electrode 1 around the inner axis of the stainless steel tube 6. During processing, the stainless steel tube 6 remains stationary.

[0116] Exemplarily, during the processing, the non-electrical parameters satisfy:

[0117] The swing speed of the driving component is 0.4-0.6 rpm, the processing gap is 10-50 μm, the processing speed is 0.02-0.045 g / min and the single-side feed amount is 2.214-2.2.316 mm.

[0118] Specifically, the universal adjustable fixture is connected to the tool electrode 1 and is used to adjust the control position of the tool electrode 1 to achieve alignment of the tool electrode to ensure machining accuracy.

[0119] Among them, Figure 12-14 As shown, the universal adjustable clamp includes a clamping part for clamping the tool electrode 1, a first adjusting part for aligning the tool electrode 1 in the XY plane direction of the machine tool, and a second adjusting part for aligning the tool electrode 1 upward in the YZ plane direction of the machine tool, wherein, from bottom to top, the clamping part, the first adjusting part and the second adjusting part are sequentially connected to each other; during alignment, the tool electrode 1 is first aligned in the XY plane direction of the machine tool using the first adjusting part, and then the tool electrode 1 is aligned in the YZ plane direction of the machine tool using the second adjusting part to ensure that the discharge end face of the tool electrode 1 is perpendicular to the position to be processed of the stainless steel pipe.

[0120] Specifically, the clamping portion includes a reference seat 10 and a clamping seat 11 installed on the reference seat 10, wherein a clamping space for installing the tool electrode 1 is provided between adjacent surfaces of the clamping seat 11 and the reference seat 10. During installation, the upper end of the tool electrode 1 is installed in the clamping space to achieve clamping of the tool electrode 1.

[0121] Furthermore, the clamping part further includes a tightening screw 12 for adjusting the clamping force of the tool electrode 1. The tightening screw 12 is screwed on the clamping seat 11, and one end thereof passes through the clamping seat 11 and is located in the clamping space. During installation, after the upper end of the tool electrode 1 is placed in the clamping space, the tightening screw 12 is rotated to squeeze the end surface of the tool electrode 1 with the tightening screw 12 to compress the tool electrode 1 to prevent it from sliding.

[0122] The inner end surface of the clamping space connected to the tool electrode 1 is a V-shaped surface, and the upper end surface of the tool electrode 1 is adapted to the V-shaped surface. The angle of the V-shaped surface is 90° to prevent the tool electrode 1 from sliding in the horizontal direction when the fastening screw 12 is pressed against the tool electrode 1. In this way, the tool electrode 1 is clamped.

[0123] Specifically, the first adjustment portion includes a first fixing seat 13 and a second fixing seat 14 distributed up and down, and the second fixing seat 14 is installed at the lower end of the first fixing seat 13 by a vertical screw 15, and a gap is provided between adjacent surfaces of the first fixing seat 13 and the second fixing seat 14; wherein, one end of the vertical screw 15 passes through the first fixing seat 13 and the second fixing seat 14, and is screwed with the first fixing seat 13, and is slidingly connected with the second fixing seat 14, and a nut is provided at the bottom of the vertical screw 15 to limit the second fixing seat 14 in a direction perpendicular to the second fixing seat 14 so as to adjust the inclination angle of the second fixing seat 14 in the horizontal direction by rotating the vertical screw 15.

[0124] There are four vertical screws 15, which are vertically and evenly distributed on the first fixing seat 13, so that by rotating any vertical screw 15, the horizontal tilt angle of the second fixing seat 14 can be partially adjusted. The tops of the four vertical screws 15 are rotating heads, which are convenient for applying force to rotate the vertical screws 15. In the initial state, the same margin gap is set between the rotating heads of all vertical screws 15 and the upper end surface of the first fixing seat to ensure that the vertical screws 15 have enough screw-in space.

[0125] Exemplarily, by rotating the vertical screw 15 located at the left end of the first fixing seat 13 clockwise, the vertical screw 15 drives the left end of the second fixing seat 14 to tilt downward.

[0126] Furthermore, an insulating plate 16 is fixedly installed at the lower end of the second fixed seat 14, and the above-mentioned reference seat 10 is fixedly connected to the lower end surface of the insulating plate 16, so that when the inclination angle of the second fixed seat 14 in the horizontal direction is adjusted, the tool electrode 1 can be aligned in the vertical direction. At the same time, the insulating plate 16 can prevent the operator from electric shock.

[0127] Exemplarily, when the left end of the second fixing seat 14 tilts downward, the lower end of the tool electrode 1 tilts rightward.

[0128] Specifically, the second adjustment part includes a clamp head 17, a first connector 18, a second connector 19 and a rotating body 20, wherein the clamp head 17 is installed on the machine tool, the first connector 18 is fixedly connected to the clamp head 17, the rotating body 20 is located between the first connector 18 and the second connector 19, and the upper end of the rotating body 20 is rotatably connected to the first connector 18 in the horizontal direction, the lower end of the rotating body 20 is fixedly connected to the second connector 19, and the lower end of the second connector 19 is fixedly connected to the top of the first fixed seat 13, so that the second connector 19 can be controlled to rotate in the horizontal plane by rotating the rotating body 20 in the horizontal direction, thereby adjusting the position of the first fixed seat 13 in the horizontal direction, and then aligning the tool electrode 1 in the YZ direction of the machine tool.

[0129] Among them, a cavity for placing a rotating body 20 is opened at the lower end of the first connecting body 18, and the rotating body 20 is placed in the cavity, and the upper end of the rotating body 20 is rotatably mounted on the top wall of the cavity; an angle adjustment bolt 21 is installed at one end of the rotating body 20, one end of the angle adjustment bolt 21 is screwed on the rotating body 20, and the other end thereof passes through the cavity wall of the first connecting body 18 and is located outside the first connecting body 18; a slot 22 is opened on the side end surface of the first connecting body 18, so that when the rotating body 20 rotates, the angle adjustment bolt 21 can slide in the slot 22; the end of the angle adjustment bolt 21 located outside the first connecting body 18 is the bolt head, and by rotating the bolt head, the angle adjustment bolt 21 can be moved closer to or away from the direction of the first connecting body, thereby adjusting the clamping force of the angle adjustment bolt 21 on the first connecting body 18, thereby adjusting the state of the rotating body 20.

[0130] Exemplarily, the angle adjustment bolt 21 is rotated counterclockwise until the pressing force of the angle adjustment bolt 21 on the first connecting body 18 is eliminated. At this time, the rotating body 20 can rotate freely, and the rotation angle is limited by the length of the notch 22.

[0131] Exemplarily, the rotation angle adjustment bolt 21 is rotated clockwise until the rotation angle adjustment bolt 21 is pressed against the end surface of the first connecting body 18 , at which time, the rotating body 20 cannot rotate.

[0132] Furthermore, a rotation angle scale is provided in the length direction of the slot 22, wherein the angle adjustment bolt 21 is located at the middle of the slot 22 at 0°, and when rotating clockwise, the maximum position of the angle adjustment bolt 21 is 10° to 30°; when rotating counterclockwise, the maximum position of the angle adjustment bolt 21 is -30° to -10°, thereby achieving precise adjustment of the angle of the rotating body 20, and further achieving precise adjustment of the tool electrode 1.

[0133] The surface with scale on the end surface of the first connecting body 18 is used as a reference surface to push the angle adjustment bolt 21 to rotate, and the pushing angle is β;

[0134] Wherein, with the center of the rotating body 20 as the center of the circle, the angle β pushed by the angle adjustment bolt 21 satisfies:

[0135]

[0136] Wherein, S: Taking the discharge end surface of the tool electrode 1 as the reference plane, the micrometer is moved in the Y-axis direction of the machine tool, and the moving distance of the micrometer needle is S;

[0137] v1 is the speed at which the micrometer moves;

[0138] t1 is the time it takes for the micrometer to move.

[0139] In the process of aligning the tool electrode 1, a micrometer is used to align the tool electrode 1 to set the reference surface to adjust the universal adjustable fixture so that the relative position error between the tool electrode and the three dimensions of the machine tool XYZ axis is ≤0.01mm.

[0140] Specifically, one end of the transmission rod 2 is fixedly connected to the reference seat 10, and the transmission rod 2 is parallel to the center line of the discharge end 101 of the tool electrode 1; during the processing, the other end of the transmission rod 2 is installed on the machine tool, so that the transmission rod 2 is driven to swing through the machine tool, and then the tool electrode 1 and the universal adjustable clamp are driven to move through the transmission rod 2, so as to realize the eccentric movement of the discharge end 101 of the tool electrode 1 around the central axis of the inner cavity of the stainless steel tube 6.

[0141] Specifically, a bearing assembly is also provided to clamp the stainless steel pipe 6 during processing; the bearing assembly includes an equal height positioning block 3 and an auxiliary bearing block 4 installed on the machine tool; the stainless steel pipe 6 is placed on the equal height positioning block 3 and the auxiliary bearing block 4 to clamp the stainless steel pipe 6.

[0142] Specifically, two equal-height positioning blocks 3 are provided, and the two equal-height positioning blocks 3 are respectively located on both sides of the position to be processed of the stainless steel tube 6 to ensure the stability of the position to be processed of the stainless steel tube 6 during the processing. Exemplarily, the distance between the two equal-height positioning blocks 3 is 20-50 mm.

[0143] Specifically, Figure 15-16 As shown, two auxiliary bearing blocks 4 are provided, and two equal-height positioning blocks 3 are located between the two auxiliary bearing blocks 4, so as to support and position the two ends of the stainless steel pipe 6 through the two auxiliary bearing blocks 4, thereby further ensuring the stability of the stainless steel pipe 6 during the processing.

[0144] The upper end surfaces of the above-mentioned equal-height positioning block 3 and the auxiliary bearing block 4 are flush, and the upper end surfaces of the equal-height positioning block 3 and the auxiliary bearing block 4 are provided with V-shaped grooves, and the stainless steel pipe 6 is placed in the V-shaped groove to limit the stainless steel pipe 6.

[0145] Furthermore, a clamping plate 5 is provided on the equal height positioning block 3, and the clamping plate 5 covers the V-shaped groove and is clamped on the equal height positioning block 3 to limit the stainless steel pipe 6 and further improve the stability of the stainless steel pipe 6. Exemplarily, the angle of the V-shaped groove is 60°-90° and the depth is 5-10 mm.

[0146] Among them, before placing the stainless steel tube 6 on the contour positioning block 3, it is first necessary to use the machine tool to align the tool electrode 1, and then insert the stainless steel tube 6 into the discharge end 101 of the tool electrode 1, and finally use the contour positioning block 3, the auxiliary supporting block 4 and the clamping plate 5 to clamp the stainless steel tube 6, and align the stainless steel tube 6 through the contour positioning block 3 and the auxiliary supporting block 4.

[0147] Specifically, after the tool electrode 1 is aligned, the positions of the contour positioning block 3 and the auxiliary supporting block 4 on the machine tool are adjusted by using the machine tool XYZ axis to align the stainless steel tube 6, ensuring that the central axis of the inner cavity of the stainless steel tube 6 coincides with the center line of the discharge end 101 of the tool electrode 1, so as to determine the value of the unilateral feed amount and thereby improve the machining accuracy.

[0148] The alignment process of the stainless steel pipe 6 is as follows.

[0149] First, fix two equal-height positioning blocks 3 and two auxiliary support blocks 4 on the workbench 9 of the machine tool, and then use a micrometer to align their sides to be parallel to the X-axis of the machine tool, with a parallelism error of ≤0.01mm.

[0150] Before placing the stainless steel tube 6 on the contour positioning block 3, first insert the stainless steel tube 6 into the discharge end 101 of the tool electrode 1, and then place the stainless steel tube 6 on the contour positioning block 3 and the auxiliary supporting block 4, so that the stainless steel tube 6 is aligned through the contour positioning block 3 and the auxiliary supporting block 4.

[0151] In addition, the present invention also provides a method for processing an annular groove, comprising the steps of:

[0152] Step 1: Use a universal adjustable fixture to clamp and align the tool electrode;

[0153] Step 2: Use the load-bearing assembly to clamp and align the stainless steel pipe;

[0154] Step 3: machining the annular groove on the surface to be machined by utilizing the working state of multiple EDM machining points of the tool electrode arranged circumferentially around the stainless steel pipe;

[0155] Wherein, the same electrospark machining point is placed in a working state or a non-working state by changing the distance between the electrospark machining point and the surface to be machined.

[0156] After the processing is completed, the damaged discharge parts are replaced to reduce the impact on the processing accuracy.

[0157] Specifically, the above step 1 includes the steps of:

[0158] S11: clamping the tool electrode 1 by using the clamping part of the universal adjustable clamp, and pressing the tool electrode 1 by using the fastening screw 12;

[0159] S12: In the XY plane direction of the machine tool, adjust the upper and lower spatial positions of the vertical screw 15 to adjust the inclination angle of the second fixing seat 14 in the horizontal direction;

[0160] S13: In the YZ plane direction of the machine tool, the position of the rotating body 20 in the horizontal plane is adjusted to adjust the inclination angle of the tool electrode 1 on the YZ plane of the machine tool.

[0161] Among them, in S11, after the upper end of the tool electrode 1 is placed in the clamping space, the fastening screw 12 is rotated, and the fastening screw 12 is used to squeeze the end surface of the tool electrode 1 to compress the tool electrode 1 to prevent it from sliding.

[0162] Furthermore, the V-shaped inner end surface of the clamping space is used to limit the tool electrode 1 to prevent the tool electrode 1 from sliding in the horizontal direction when the fastening screw 12 is pressing the tool electrode 1 .

[0163] Specifically, in S12, the first adjusting portion of the universally adjustable fixture is used to adjust the inclination angle of the tool electrode 1 in the horizontal direction.

[0164] By rotating any vertical screw 15 , the tilt angle of the second fixing seat 14 in the horizontal direction can be partially adjusted.

[0165] Exemplarily, the vertical screw 15 located at the left end of the first fixing seat 13 is rotated clockwise so that the vertical screw 15 drives the left end of the second fixing seat 14 to tilt downward, and then transmits through the insulating plate so that the lower end of the tool electrode 1 tilts to the right.

[0166] Specifically, in S13, the second adjustment portion of the universally adjustable fixture is used to adjust the inclination angle of the tool electrode 1 in the YZ direction of the machine tool.

[0167] The rotating body 20 rotates in the horizontal direction to control the second connecting body 19 to rotate in the horizontal plane, thereby adjusting the position of the first fixing seat 13 in the horizontal direction, thereby aligning the tool electrode 1 in the YZ direction of the machine tool.

[0168] By rotating the bolt head, the angle adjustment bolt 21 can be moved closer to or farther away from the first connecting body, thereby adjusting the pressing force of the angle adjustment bolt 21 on the first connecting body 18, thereby adjusting the state of the rotating body 20.

[0169] Exemplarily, the angle adjustment bolt 21 is rotated counterclockwise until the pressing force of the angle adjustment bolt 21 on the first connecting body 18 is eliminated. At this time, the rotating body 20 can rotate freely, and the rotation angle is limited by the length of the notch 22.

[0170] Exemplarily, the rotation angle adjustment bolt 21 is rotated clockwise until the rotation angle adjustment bolt 21 is pressed against the end surface of the first connecting body 18 , at which time, the rotating body 20 cannot rotate.

[0171] The surface with scale on the end surface of the first connecting body 18 is used as a reference surface to push the angle adjustment bolt 21 to rotate, and the pushing angle is β;

[0172] Wherein, with the center of the rotating body 20 as the center of the circle, the angle β pushed by the angle adjustment bolt 21 satisfies:

[0173]

[0174] Wherein, S: Taking the discharge end surface of the tool electrode 1 as the reference plane, the micrometer is moved in the Y-axis direction of the machine tool, and the moving distance of the micrometer needle is S;

[0175] v1 is the speed at which the micrometer moves;

[0176] t1 is the time it takes for the micrometer to move.

[0177] In the process of aligning the tool electrode 1, a micrometer is used to align the tool electrode 1 to set the reference surface to adjust the universal adjustable fixture so that the relative position error between the tool electrode and the three dimensions of the machine tool XYZ axis is ≤0.01mm.

[0178] Specifically, in step 2, the stainless steel tube 6 is placed on the equal height positioning block 3 and the auxiliary bearing block 4 to clamp the stainless steel tube 6.

[0179] Two equal-height positioning blocks 3 are used to clamp the two sides of the position to be processed of the stainless steel tube 6, so as to ensure the stability of the position to be processed of the stainless steel tube 6 during the processing. Exemplarily, the distance between the two equal-height positioning blocks 3 is 20-50 mm.

[0180] Among them, two equal-height positioning blocks 3 are placed between two auxiliary bearing blocks 4, so as to support and position the two ends of the stainless steel pipe 6 through the two auxiliary bearing blocks 4, and further ensure the stability of the stainless steel pipe 6 during the processing.

[0181] The stainless steel tube 6 is placed in the V-shaped grooves formed on the upper end surfaces of the equal height positioning block 3 and the auxiliary bearing block 4 to limit the position of the stainless steel tube 6 .

[0182] Furthermore, the clamping plate 5 is covered on the V-shaped groove and clamped on the equal height positioning block 3 to limit the stainless steel pipe 6 and further improve the stability of the stainless steel pipe 6. Exemplarily, the angle of the V-shaped groove is 60°-90° and the depth is 5-10 mm.

[0183] Among them, before placing the stainless steel tube 6 on the contour positioning block 3, it is first necessary to use the machine tool to align the tool electrode 1, and then insert the stainless steel tube 6 into the discharge end 101 of the tool electrode 1, and finally use the contour positioning block 3, the auxiliary supporting block 4 and the clamping plate 5 to clamp the stainless steel tube 6, and align the stainless steel tube 6 through the contour positioning block 3 and the auxiliary supporting block 4.

[0184] Specifically, after the tool electrode 1 is aligned, the positions of the contour positioning block 3 and the auxiliary supporting block 4 on the machine tool are adjusted by using the machine tool XYZ axis to align the stainless steel tube 6, ensuring that the central axis of the inner cavity of the stainless steel tube 6 coincides with the center line of the discharge end 101 of the tool electrode 1, so as to determine the value of the unilateral feed amount and thereby improve the machining accuracy.

[0185] The alignment process of the stainless steel pipe 6 is as follows.

[0186] First, fix two equal-height positioning blocks 3 and two auxiliary support blocks 4 on the workbench 9 of the machine tool, and then use a micrometer to align their sides to be parallel to the X-axis of the machine tool, with a parallelism error of ≤0.01mm.

[0187] Before placing the stainless steel tube 6 on the contour positioning block 3, first insert the stainless steel tube 6 into the discharge end 101 of the tool electrode 1, and then place the stainless steel tube 6 on the contour positioning block 3 and the auxiliary supporting block 4, so that the stainless steel tube 6 is aligned through the contour positioning block 3 and the auxiliary supporting block 4.

[0188] Specifically, in step 3, the tool electrode 1 is clamped in the clamping part, and the reference seat 10 of the clamping part is connected to the driving assembly, which includes a transmission rod 2, that is, one end of the transmission rod 2 is connected to the reference seat 10 and is parallel to the center line of the discharge end 101 of the tool electrode 1; during the processing, the other end of the transmission rod 2 is installed on the machine tool, so that the transmission rod 2 is driven to swing through the machine tool, and then the tool electrode 1 and the universal adjustable clamp are driven to move through the transmission rod 2, so that the discharge end 101 of the tool electrode 1 can move eccentrically around the central axis of the inner cavity of the stainless steel tube 6, thereby realizing the discharge end 101 of the tool electrode to perform electric spark machining around the end face of the stainless steel tube 6, and the processing direction 7 is the circumferential direction around the outer end face of the stainless steel tube 6, and the center line of the circumferential direction coincides with the central axis of the inner cavity of the stainless steel tube 6.

[0189] Specifically, before the tool electrode 1 makes an eccentric movement, it is necessary to adjust the center of the inner round end of the discharge end 101 of the tool electrode 1 to coincide with the central axis of the stainless steel tube 6, and there is a margin gap between the discharge end 101 and the outer end surface of the stainless steel tube 6, that is, the diameter of the inner round end of the discharge end 101 is larger than the outer diameter of the stainless steel tube 6. For example, the diameter of the inner round end is 10 to 20 mm, which is 5 to 10 times the outer diameter of the stainless steel tube 6. In this way, during the electrospark machining process, it is convenient to determine the value of the single-side feed amount O1O2.

[0190] Among them, the single-side feed amount O1O2 satisfies:

[0191] O1O2=S1+(H1-H2)-S2

[0192] Wherein, O1 represents the center point of the discharge end 101 of the tool electrode 1;

[0193] O2 represents the center point of the inner cavity of the stainless steel tube 6;

[0194] H1 is the wall thickness of the stainless steel tube 6;

[0195] H2 is the wall thickness of the fracture groove 601;

[0196] S1 is a residual gap between the discharge end 101 and the outer end surface of the stainless steel tube 6;

[0197] S2 is the machining gap, which refers to the shortest distance between the working end 102 and the end face of the stainless steel tube 601 when the tool electrode 1 moves eccentrically.

[0198] Among them, S1 satisfies:

[0199]

[0200] Among them, S 11 , S 12 , S 13 , S14 are actual margin gap values ​​between four points selected on the discharge end 101 of the tool electrode 1 and the outer end surface of the stainless steel tube 6 , and the four points are evenly distributed on the discharge end 101 .

[0201] For example, S 11 , S 12 , S 13 , S 14 They are 2.055mm, 2.060mm, 2.065mm and 2.050mm respectively. At this time, S1=2.058mm.

[0202] The machining gap S2 is set to 10-50 μm to meet the requirements of EDM.

[0203] Exemplarily, S2=10 μm; H1=0.5 mm, H2=0.3 mm, S1=2.058 mm, then O1O2=2.248 mm.

[0204] Among them, the automatic centering module on the machine tool can be used to measure S 11 , S 12 , S 13 , S 14 , wherein, if the four values ​​are equal, the center of the inner circular end of the discharge end 101 of the tool electrode 1 coincides with the central axis of the inner cavity of the stainless steel tube 6 .

[0205] Among them, after the center of the discharge end 101 of the tool electrode 1 is adjusted by the machine tool to coincide with the inner axis of the stainless steel tube 6, the actual measured S 11 , S 12 , S 13 , S 14 The closer the four values ​​are, the more accurate the value of S1 is, and thus the more accurate the single-sided feed amount O1O2 is. In this way, during the eccentric movement of the tool electrode 1, the accuracy of the machining gap can be ensured, and then the machining depth of the working end 102 can be guaranteed to ensure the dimensional accuracy of the machined fracture groove 601.

[0206] Specifically, after adjusting the center of the discharge end 101 of the tool electrode 1 to coincide with the central axis of the inner cavity of the stainless steel tube 6, the tool electrode 1 is driven by a machine tool to perform eccentric motion. The detailed process is as follows.

[0207] The motion trajectories of the center point O1 of the discharge end 101 of the tool electrode 1 and the center point O2 of the inner cavity of the stainless steel tube 6 are described as follows:

[0208] Move the tool electrode 1 so that O1 is away from O2. The moving distance is the same as the single-side feed amount O1O2. At this time, the distance between O1 and O2 is O1O2.

[0209] With O2 as the center and O1O2 as the radius, rotate O1 around O2. At this time, the trajectory of O1's movement is a circle, the center of the circle is O2, and the radius is O1O2;

[0210] In the process of moving O1, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel tube 6 reaches 10 μm, the power supply device is turned on to transmit a pulse voltage to the tool electrode 1 and the stainless steel tube 6, and the metal on the surface of the stainless steel tube 6 is etched at a processing speed of 0.04 g / min until the distance between O1 and O2 is O1O2, and then O1 moves in a circle around O2.

[0211] In order to further illustrate the motion trajectory of the tool electrode 1, an arbitrary point O3 on the discharge end 101 is selected and the trajectory of O3 is used for explanation as follows:

[0212] Move the tool electrode 1 so that O3 moves toward O2, and the moving distance is O1O2;

[0213] When O1 rotates around O2, at this time, the trajectory of O3 is: a circle with the initial position of O3 as the center and O1O2 as the radius;

[0214] Among them, during the movement of O3, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel tube 6 reaches 10μm, the power supply device is turned on to transmit a pulse voltage to the tool electrode 1 and the stainless steel tube 6, and the metal on the surface of the stainless steel tube 6 is etched at a processing speed of 0.04g / min until the moving distance of O3 reaches O1O2, and then O3 moves in a circle with its initial position as the center.

[0215] In this way, during the eccentric movement of the tool electrode 1, the distance between the inner circular end surface of the discharge end 101 and the outer surface of the stainless steel tube 6 is constantly changing, and the distance between each part of the inner circular end surface of the discharge end 101 and the outer end surface of the stainless steel tube 6 is changed from close to far away. Then, the discharge end 101 is changed from a working state to a non-working state, that is, a dynamic transition between the working end 102 and the non-working end 103 is realized.

[0216] There is a margin gap between the discharge end 101 and the outer end surface of the stainless steel tube 601 to ensure that the non-processing gap between the non-working end 103 at the discharge end 101 and the end surface of the stainless steel tube 6 is large enough, thereby ensuring that the pulse voltage released at the non-working end 103 cannot erode the metal on the surface of the stainless steel tube 6. In this way, when the tool electrode 1 moves eccentrically, the working end 102 and the non-working end 103 can be dynamically transformed.

[0217] During processing, the stainless steel tube 6 and the discharge end 101 of the tool electrode 1 are immersed in a liquid medium with a certain degree of insulation. For example, the medium is kerosene, mineral oil or deionized water. When a pulse voltage is applied to the discharge end 101 and the stainless steel tube 6, the liquid medium at the closest point between the stainless steel tube 6 and the discharge end 101 under the current conditions is broken down to form a discharge channel. Since the cross-sectional area of ​​the channel is very small, the discharge time is extremely short, resulting in a high concentration of energy (10 6 W / cm 2 ), the instantaneous high temperature generated in the discharge area is enough to melt or even evaporate the metal on the surface of the stainless steel tube 6, so as to form a small pit; after the first pulse discharge ends, after a very short interval, the second pulse breaks through and discharges at the nearest point between the other electrodes, and so on, the high-frequency cycle is repeated over and over again, and the tool electrode 1 is continuously fed to the stainless steel tube 6, and its shape is finally copied on the stainless steel tube 6 to form the required processing surface; during the processing, although a small part of the total energy is also released to the tool electrode 1, causing the tool electrode 1 to be lost, but through the eccentric movement of the discharge end 101 of the tool electrode 1 around the central axis of the inner cavity of the stainless steel tube 6, the working end 102 at the discharge end 101 is constantly changing its position, thereby reducing the loss of the tool electrode 1 by avoiding continuous processing of the working end 102, and then, at each moment of processing, the working end 102 of the discharge end 101 maintains a relatively complete shape, thereby improving the processing accuracy.

[0218] Exemplarily, during the processing, the electrical parameters satisfy:

[0219] The pulse width is 30 to 60 μs, the pulse interval is 20 to 30 μs, the average processing current is 0.8 to 2A, and the average processing voltage is 30 to 60V.

[0220] Specifically, during processing, the tool electrode 1 is controlled by the machine tool to move eccentrically, while the stainless steel tube 6 remains stationary.

[0221] The tool electrode 1 is connected to a driving device arranged on a machine tool, and the driving device includes a transmission rod 2. During processing, the machine tool controls the transmission rod 2 to swing, and then drives the tool electrode 1 to perform eccentric motion through the transmission rod 2.

[0222] Specifically, the transmission rod 2 swings clockwise in a swing plane ZY, and the swing plane ZY is parallel to the plane where the discharge end 101 is located, thereby achieving eccentric movement of the tool electrode 1 around the central axis of the inner cavity of the stainless steel tube 6.

[0223] Exemplarily, during the processing, the non-electrical parameters satisfy:

[0224] The swing speed of the driving component is 0.4-0.6 rpm, the processing gap is 10-50 μm, and the processing speed is 0.02-0.045 g / min.

[0225] Thus, the discharge end 101 of the tool electrode 1 eccentrically moves around the central axis of the inner cavity of the stainless steel tube 6 for one circle, and the processing of the broken groove 601 of the stainless steel tube can be completed, and the processing is completed in one time, and the processing efficiency is significantly improved.

[0226] Compared with the prior art, the discharge part and the conductive part of the tool electrode of the present invention are detachably connected. After electrospark machining, there is no need to remove the entire tool electrode from the universal adjustable clamp for replacement. The damaged tool electrode can be replaced by replacing the discharge part. In this way, the tool electrode can be clamped without adjusting the universal adjustable clamp again, which makes replacement convenient.

[0227] The discharge component is composed of a plurality of fan-shaped discharge parts. After the processing is completed, the partially damaged fan-shaped discharge parts can be replaced, thereby avoiding the increased processing cost caused by the overall replacement of the discharge component. At the same time, for the processing of annular grooves with various shapes, it is not necessary to design and process the entire tool electrode to adapt to the annular groove. The electric spark processing of annular grooves with various shapes can be achieved by replacing some fan-shaped discharge parts, thereby reducing the processing cost of the annular grooves.

[0228] The inclination angle of the tool electrode 1 on the horizontal plane is adjusted by the first adjustment part of the universal adjustable clamp; the inclination angle of the tool electrode 1 on the YZ plane of the machine tool is determined according to the detection value of the micrometer and the time and speed of the movement of the micrometer, and the angle scale value on the first connector 18 is compared, and the angle adjustment bolt 21 is pushed to the corresponding scale, so that the inclination angle of the tool electrode 1 on the YZ plane of the machine tool can be adjusted with high precision, thereby realizing the alignment of the tool electrode 1, which is easy to operate and improves the processing efficiency and accuracy.

[0229] During processing, it is only necessary to place the ultra-slender stainless steel tube 6 in the V-shaped grooves on the equal height positioning block 3 and the auxiliary bearing block 4, and use the clamping plate 5 to limit the upper surface of the ultra-slender stainless steel tube, so as to achieve the clamping and positioning of the ultra-slender stainless steel tube. The clamping is convenient and can ensure the stability of the ultra-slender stainless steel tube 6 during the processing.

[0230] The discharge end 101 of the tool electrode 1 of the present invention is annular, and is sleeved on the outer end face of the ultra-slender stainless steel tube 6 to make an eccentric movement. During this process, the distance between the end face of the discharge end 101 and the end face to be processed of the ultra-slender stainless steel tube 6 is constantly changing, the closer distance is the working end 102, and the farther distance is the non-working end 103, so that the outer end face of the ultra-slender stainless steel tube 6 is electrospark machined by the working end 102; that is, along the machining direction, the position of the working end 102 on the inner circular end face of the discharge end 101 is constantly changing, that is, when the inner circular end face of the discharge end 101 is close to the ultra-slender stainless steel tube 6, the discharge end 101 is placed on the inner circular end face of the discharge end 101. When the discharge end 101 is close to the outer end face of the ultra-slender stainless steel tube 6, the end face of the discharge end 101 is the working end 102. When the end face is away from the outer end face of the ultra-slender stainless steel tube 6, the end face is transformed into the non-working end 103, realizing the dynamic transformation between the working end 102 and the non-working end 103, thereby avoiding the working end 102 of the tool electrode 1 from being in a continuous processing state, greatly reducing the loss of the working end 102 of the tool electrode 1, realizing the tool electrode loss ≤1%, thereby reducing the deformation of the working end face of the tool electrode 1, thereby improving the accuracy of processing the fracture groove 601 of the ultra-slender stainless steel tube.

[0231] The discharge end 101 of the tool electrode 1 of the present invention is sleeved on the ultra-slender stainless steel tube 6 for eccentric movement. During processing, the distance between the discharge end 101 and the ultra-slender stainless steel tube 6 changes from large to small, and then changes from small to large. In the process of the distance changing from large to small, metal debris will be generated between the discharge end 101 and the stainless steel tube 6. At this time, part of the metal debris will be discharged through the processing gap with the working fluid. In the process of the distance changing from small to large, the distance between the discharge end 101 and the stainless steel tube 6 can be increased by nearly 200 times, which significantly improves the efficiency of discharging metal debris, thereby avoiding the accumulation of metal debris at the discharge end 101 due to untimely discharge, thereby reducing the loss of the tool electrode 1, and avoiding the risk of short circuit caused by the tool electrode 1 being directly connected to the stainless steel tube 6 through the metal debris.

[0232] By sleeved the discharge end 101 of the tool electrode 1 on the ultra-slender stainless steel tube 6 for eccentric movement, metal debris can be efficiently discharged, thereby realizing electrospark machining with a smaller machining gap, thereby reducing the machining current and machining voltage values, reducing the machining cost, and obtaining a fracture groove 601 with a lower surface roughness.

[0233] By adjusting the value of the unilateral feed amount, the fracture grooves 601 with different wall thicknesses can be processed. By adjusting the shape of the discharge end 101 of the tool electrode 1, the size processing of different bevel angles α can be achieved, laying the foundation for rapid production and mass production of products.

[0234] The discharge end 101 of the tool electrode 1 of the present invention can complete the processing of the ultra-slender stainless steel tube fracture groove 601 by eccentrically moving around the inner cavity center axis of the ultra-slender stainless steel tube 6, achieving one-time processing and significantly improving the processing efficiency.

[0235] Example 1

[0236] An assembled electrode for machining annular grooves comprises: a conductive member 25, and a discharge member electrically connected to the conductive member, wherein the discharge member is sleeved on a workpiece to be machined and moves eccentrically around the workpiece to be machined to realize electric spark machining of the annular groove of the workpiece to be machined; wherein the discharge end of the discharge member matches the shape of the annular groove, and the discharge member and the conductive member are detachably connected.

[0237] Specifically, the conductive member includes a conductive rod, one end of which is a conductive end and is clamped on a universally adjustable fixture, and the other end of which is electrically connected to the discharge member.

[0238] Specifically, the tool electrode 1 includes four limiting plates 27 and a clamping member 28 for fixing the limiting plates 27. The four limiting plates 27 surround a clamping space for fixing and connecting one end of the conductive rod and the discharge member. The discharge member and one end of the conductive rod are respectively inserted into the clamping space, and the discharge member and one end of the conductive rod are respectively fastened in the clamping space by the clamping member 28, so that the discharge member is connected to the conductive member 25.

[0239] Among them, the clamping parts 28 are two arc-shaped plates, which are attached to the outside of the four limit plates 27. The two arc-shaped plates are fastened to each other by bolts, so that pressure is applied to the four limit plates 27, so that the four limit plates 27 are squeezed toward the discharge part and the conductive rod, thereby achieving the discharge part and the conductive rod being fastened in the clamping space.

[0240] The discharge member is a circular ring structure, and a connecting portion is provided at the upper end of the circular ring discharge member. The connecting portion is used to be placed in the clamping space and electrically connected to the conductive rod.

[0241] Specifically, the discharge member and the conductive member are connected to form a complete tool electrode 1. At this time, one end of the tool electrode 1 is in a circular ring shape, and the inner circular end of the circular ring matches the shape of the broken groove 601. The other end of the tool electrode 1 is a conductive end 104, which is electrically connected to an output end of a power supply device arranged on the machine tool to introduce current and transmit the current to the inner circular end. At this time, the inner circular end is the discharge end 101, and the discharge end 101 is sleeved on the outer end surface of the stainless steel pipe 6; during processing, the stainless steel pipe 6 is electrically connected to the other output end of the power supply device, and the discharge end 101 of the tool electrode 1 moves eccentrically around the central axis of the inner cavity of the stainless steel pipe 6, wherein, during the eccentric movement of the tool electrode 1, the distance between the end face of the discharge end 101 and the end face to be processed of the stainless steel pipe 6 is constantly changing, and the distance is 10-50μm for the working state, that is, the working end 102, and the distance is greater than 50μm for the non-working state, that is, the non-working end 103. The processing tracks of all the working ends 102 together form an ultra-slender stainless steel pipe breaking groove 601 .

[0242] Among them, the center of the inner circular end of the discharge end 101 of the tool electrode 1 coincides with the central axis of the inner cavity of the stainless steel tube 6, and there is a residual gap between the discharge end 101 and the outer end face of the stainless steel tube 6, wherein the end face diameter of the discharge end 101 is 20 mm, which is 10 times the outer diameter of the stainless steel tube 6, so as to facilitate the determination of the value of the single-sided feed amount O1O2; during processing, the tool electrode 1 is driven to swing by the driving component, at this time, the discharge end 101 of the tool electrode 1 is in an eccentric motion state around the central axis of the inner cavity of the stainless steel tube 6.

[0243] Among them, the automatic centering module on the machine tool is used to measure S 11 , S 12 , S 13 , S 14 They are 2.055mm, 2.060mm, 2.065mm and 2.050mm respectively. At this time, S1=2.058mm.

[0244] Among them, S2=10μm; H1=0.5mm, H2=0.3mm, S1=2.058mm, at this time, O1O2=2.248mm.

[0245] After adjusting the center of the discharge end 101 of the tool electrode 1 to coincide with the central axis of the inner cavity of the stainless steel tube 6 , the tool electrode 1 is in an eccentric motion state under the action of the driving assembly.

[0246] Among them, the conductive end 104 of the tool electrode 1 is electrically connected to an output end of a power supply device arranged on the machine tool, and the stainless steel tube 6 is electrically connected to another output end of the power supply device. The power supply device includes a pulse power supply, and its two output ends are respectively connected to the positive and negative poles of the pulse power supply to output a pulse voltage.

[0247] Among them, during the processing, the electrical parameters meet:

[0248] Pulse width 40μs, pulse interval 26μs, average machining current 1A, average machining voltage 40V.

[0249] Specifically, a transmission rod 2 is provided to drive the tool electrode to move; wherein one end of the transmission rod 2 is connected to the tool electrode 1, and the other end of the transmission rod 2 is installed on the machine tool, and the transmission rod 2 can be controlled to swing through the machine tool, and then the transmission rod 2 drives the discharge end 101 of the tool electrode 1 to move eccentrically around the central axis of the inner cavity of the stainless steel tube 6. During processing, the stainless steel tube 6 remains stationary.

[0250] Among them, during the processing, the non-electrical parameters meet the following requirements:

[0251] The swing speed of the transmission rod 2 is 0.5 rpm, the processing gap S2 is 10 μm, the processing speed is 0.04 g / min, and the single-side feed amount O1O2 is 2.248 mm.

[0252] Specifically, a universally adjustable clamp is also provided to clamp and align the tool electrode; wherein, the universally adjustable clamp includes a clamping part, a first adjustment part, and a second adjustment part; wherein, the clamping part includes a reference seat 10 and a clamping seat 11 installed on the reference seat 10, wherein a clamping space for installing the tool electrode 1 is provided between the adjacent surfaces of the clamping seat 11 and the reference seat 10, and when installed, the upper end of the tool electrode 1 is installed in the clamping space, including a fastening screw 12 for adjusting the clamping force of the tool electrode 1, the fastening screw 12 is screwed on the clamping seat 11, and one end thereof passes through the clamping seat 11 and is located in the clamping space.

[0253] The inner end surface of the clamping space connected to the tool electrode 1 is a V-shaped surface, and the angle of the V-shaped surface is 90°.

[0254] Among them, the first adjustment part includes a first fixing seat 13 and a second fixing seat 14 distributed up and down, the second fixing seat 14 is installed on the lower end of the first fixing seat 13 by four vertical screws 15, and a gap is provided between the adjacent surfaces of the first fixing seat 13 and the second fixing seat 14; wherein, one end of the vertical screw 15 passes through the first fixing seat 13 and the second fixing seat 14, and is screwed with the first fixing seat 13, and is slidingly connected with the second fixing seat 14, and a nut is provided at the bottom of the vertical screw 15 to limit the second fixing seat 14 in a direction perpendicular to the second fixing seat 14 so as to adjust the inclination angle of the second fixing seat 14 in the horizontal direction by rotating the vertical screw 15.

[0255] An insulating plate 16 is fixedly mounted on the lower end of the second fixing seat 14 , and the reference seat 10 is fixedly connected to the lower end surface of the insulating plate 16 .

[0256] Among them, the second adjustment part includes a clamp head 17, a first connecting body 18, a second connecting body 19 and a rotating body 20, wherein the clamp head 17 is installed on the machine tool, the first connecting body 18 is fixedly connected to the clamp head 17, the rotating body 20 is located between the first connecting body 18 and the second connecting body 19, and the upper end of the rotating body 20 is rotatably connected to the first connecting body 18 in the horizontal direction, the lower end of the rotating body 20 is fixedly connected to the second connecting body 19, and the lower end of the second connecting body 19 is fixedly connected to the top of the first fixed seat 13.

[0257] Among them, a cavity for placing a rotating body 20 is opened at the lower end of the first connecting body 18, and the rotating body 20 is placed in the cavity, and the upper end of the rotating body 20 is rotatably mounted on the top wall of the cavity; an angle adjustment bolt 21 is installed at one end of the rotating body 20, one end of the angle adjustment bolt 21 is screwed on the rotating body 20, and the other end thereof passes through the cavity wall of the first connecting body 18 and is located outside the first connecting body 18; a slot 22 is opened on the side end surface of the first connecting body 18, so that when the rotating body 20 rotates, the angle adjustment bolt 21 can slide in the slot 22.

[0258] A rotation angle scale is provided in the length direction of the slot 22 to precisely control the pushing angle of the rotation angle adjustment bolt and improve the alignment accuracy of the tool electrode on the YZ plane of the machine tool.

[0259] The angle β pushed by the angle adjustment bolt 21 satisfies:

[0260]

[0261] Wherein, S: Taking the discharge end surface of the tool electrode 1 as the reference plane, the micrometer is moved in the Y-axis direction of the machine tool, and the moving distance of the micrometer needle is S;

[0262] v1 is the speed at which the micrometer moves;

[0263] t1 is the time it takes for the micrometer to move.

[0264] Specifically, the moving component includes a transmission rod 2, one end of which is fixedly connected to the reference seat 10, and the transmission rod 2 is parallel to the center line of the discharge end 101 of the tool electrode 1; during the processing, the other end of the transmission rod 2 is installed on the machine tool, so that the transmission rod 2 is driven to swing through the machine tool, and then the tool electrode 1 and the universal adjustable clamp are driven to move through the transmission rod 2, so as to realize the eccentric movement of the discharge end 101 of the tool electrode 1 around the central axis of the inner cavity of the stainless steel tube 6.

[0265] Specifically, a bearing assembly is also provided to clamp and align the stainless steel pipe; wherein the bearing assembly includes an equal height positioning block 3 and an auxiliary support block 4 installed on the machine tool, so that the stainless steel pipe 6 is placed on the equal height positioning block 3 and the auxiliary bearing block 4 to clamp the stainless steel pipe 6.

[0266] There are two equal-height positioning blocks 3 , which are respectively located on both sides of the position to be processed of the stainless steel pipe 6 , and the distance between the two equal-height positioning blocks 3 is 30 mm.

[0267] There are two auxiliary bearing blocks 4 , and two equal-height positioning blocks 3 are located between the two auxiliary bearing blocks 4 , so as to support and position the two ends of the stainless steel pipe 6 through the two auxiliary bearing blocks 4 .

[0268] Among them, the upper end surfaces of the equal height positioning block 3 and the auxiliary bearing block 4 are flush, and the upper end surfaces of the equal height positioning block 3 and the auxiliary bearing block 4 are provided with V-shaped grooves, and the stainless steel pipe 6 is placed in the V-shaped groove to limit the stainless steel pipe 6.

[0269] Furthermore, a clamping plate 5 is provided on the equal height positioning block 3, and the clamping plate 5 covers the V-shaped groove and is clamped on the equal height positioning block 3 to limit the stainless steel pipe 6 and further improve the stability of the stainless steel pipe 6. Exemplarily, the angle of the V-shaped groove is 90° and the depth is 10 mm.

[0270] Among them, before placing the stainless steel tube 6 on the contour positioning block 3, it is necessary to first align the tool electrode 1, and then insert the stainless steel tube 6 into the discharge end 101 of the tool electrode 1, and finally use the contour positioning block 3, the auxiliary supporting block 4 and the clamping plate 5 to clamp the stainless steel tube 6, and align the stainless steel tube 6 through the contour positioning block 3 and the auxiliary supporting block 4.

[0271] Example 2

[0272] An assembled electrode for machining annular grooves, which differs from Example 1 in that: the discharge member is a continuous annular structure, the end of the conductive rod electrically connected to the discharge member is an annular structure, the discharge member is detachably mounted on the annular end of the conductive rod, and the inner center of the discharge member coincides with the inner center of the annular end of the conductive rod.

[0273] The outer circular end of the discharge member is the mounting end, and a groove 32 for placing the mounting end is provided on the step hole of the conductive rod. The mounting end is stuck in the groove 32, and the discharge member is electrically connected to the conductive rod through its mounting end.

[0274] A circular ring-shaped limiting plate 29 is also provided on the step hole of the conductive rod. The circular ring-shaped limiting plate 29 is fixedly mounted on the conductive rod by bolts to press the mounting end of the discharge member into the groove 32 .

[0275] Wherein, the inner diameter of the annular discharge member is smaller than the inner diameter of the step hole of the conductive rod.

[0276] Example 3

[0277] An assembled electrode for machining annular grooves, which differs from Example 1 in that: the discharge member includes a plurality of fan-shaped discharge portions 30, and the plurality of fan-shaped discharge portions 30 form a circular ring-shaped discharge member 26; the end of the conductive rod electrically connected to the discharge member is a circular ring structure, and the discharge member is detachably mounted on the circular ring-shaped end of the conductive rod, and the inner center of the discharge member coincides with the inner center of the circular ring-shaped end of the conductive rod.

[0278] The outer circular end of the discharge member is the mounting end, and a groove 32 for placing the mounting end is provided on the step hole of the conductive rod. The mounting end is stuck in the groove 32, and the discharge member is electrically connected to the conductive rod through its mounting end.

[0279] Among them, a plurality of sector-shaped limiting plates 31 are further provided on the step hole of the conductive rod, and the plurality of sector-shaped limiting plates 31 form a circular ring-shaped limiting plate 29 .

[0280] The plurality of fan-shaped limiting plates 31 are respectively fixedly mounted on the conductive rod by bolts, so as to respectively press the plurality of fan-shaped discharge portions 30 onto the step holes of the conductive rod.

[0281] Wherein, the inner diameter of the annular discharge member is smaller than the inner diameter of the step hole of the conductive rod.

[0282] Example 4

[0283] A method for processing an annular groove comprises the following steps:

[0284] Step 1: Use a universal adjustable fixture to align the tool electrode;

[0285] Specifically, the spatial position of the tool electrode 1 is adjusted by adjusting the spatial position of the universally adjustable fixture 5 .

[0286] The tool electrode 1 is fixed on the universally adjustable fixture 5, the tool electrode 1 is aligned with the reference surface using a micrometer, and the universally adjustable fixture is adjusted so that the relative position error between the tool electrode 1 and the three dimensions of the machine tool XYZ axis is ≤0.01mm.

[0287] Specifically, select the reference plane in the XYZ three-dimensional direction on the tool electrode, touch the reference plane with the dial head respectively, and then move the dial indicator. If the needle on the dial shows a movement of 0-10μm, the accuracy meets the requirements and the alignment process is ended. If the needle on the dial shows a movement greater than 10μm, the accuracy does not meet the requirements. Use the universal adjustable fixture to adjust the position of the tool electrode in three dimensions on the machine tool until the needle on the dial shows a movement of 0-10μm, so as to achieve the alignment of the tool electrode.

[0288] Among them, the micrometer is used to align the tool electrode in the three dimensions of the machine tool XYZ. After the alignment is completed, the value moved by the needle of the micrometer in the three dimensions of XYZ is the alignment error, that is, the relative position error.

[0289] Among them, in the three directions of the machine tool XYZ axis, a small plane can be machined on the tool electrode as a reference plane.

[0290] Exemplarily, in the Z-axis direction of the machine tool, a micrometer is used to align the tool electrode; wherein, the discharge end face of the tool electrode is used as the reference plane, the head of the micrometer is touched to the upper horizontal plane of the transmission rod, and the micrometer is moved up and down. If the needle of the micrometer moves 0-10μm, the position of the tool electrode in the Z-axis direction meets the requirements. If the needle of the micrometer moves more than 10μm, the position of the tool electrode is adjusted by the first adjustment part of the universal adjustable clamp. After adjustment, the micrometer is used to continue to detect until the micrometer moves within 0-10μm.

[0291] Among them, the adjustment process of the universal adjustable fixture is as follows:

[0292] Specifically, firstly, the tool electrode is installed in the clamping part, and the tool electrode is compressed by a tightening screw;

[0293] Next, the discharge end surface of the tool electrode is used as a reference surface, the dial gauge head touches the reference surface and moves in the Z-axis direction of the machine tool. If the needle of the dial gauge moves 0-10 μm, the position of the tool electrode does not need to be adjusted in the front-back direction of the XY plane of the machine tool. If the needle of the dial gauge moves more than 10 μm, the position of the tool electrode needs to be adjusted by the first adjustment unit.

[0294] Among them, in the process of the micrometer moving upward, if the needle moves clockwise, the upper end of the tool electrode tilts toward the reference plane, if the needle moves counterclockwise, the upper end of the tool electrode tilts in the opposite direction of the reference plane. At this time, by adjusting the upper and lower spatial positions of the vertical screws on both sides of the discharge end face, the tool electrode can be aligned in the front and rear directions of the XY plane of the machine tool.

[0295] The vertical screw at the upper side is rotated clockwise, and the vertical screw at the lower side is rotated counterclockwise, so as to align the tool electrode in the front-to-back direction of the XY plane of the machine tool.

[0296] Next, using the upper end surface of the second fixing seat as a reference surface, the dial gauge head is touched to the reference surface and moved in the Y-axis direction of the machine tool. If the needle of the dial gauge moves 0-10 μm, the position of the tool electrode does not need to be adjusted in the left-right direction of the XY plane of the machine tool. If the needle of the dial gauge moves more than 10 μm, the position of the tool electrode needs to be adjusted by the first adjustment unit.

[0297] Among them, the upper end surface of the tool electrode is a plane, which is parallel to the center line of the discharge end and connected to the lower end surface of the insulating plate. The upper end surface of the second fixed seat is parallel to the upper end surface of the tool electrode. Therefore, the tool electrode can be aligned in the left and right directions of the XY plane of the machine tool using the upper end surface of the second fixed seat as the reference plane.

[0298] Among them, when the micrometer moves to the right, if the needle moves clockwise, the right end of the second fixed seat is too high. At this time, the vertical screw close to the right end of the second fixed seat can be adjusted to make it rotate clockwise, or the vertical screw close to the left end of the second fixed seat can be adjusted to make it rotate counterclockwise.

[0299] Among them, when the micrometer moves to the right, if the needle moves counterclockwise, the left end of the second fixed seat is too high. At this time, the vertical screw close to the left end of the second fixed seat can be adjusted to rotate clockwise, or the vertical screw close to the right end of the second fixed seat can be adjusted to rotate counterclockwise, so as to realize the alignment of the tool electrode in the left and right directions of the XY plane of the machine tool.

[0300] Next, the discharge end surface of the tool electrode is used as a reference surface, the dial gauge head touches the reference surface, and moves in the Y-axis direction of the machine tool; if the needle of the dial gauge moves 0-10 μm, the position of the tool electrode does not need to be adjusted in the YZ plane direction of the machine tool; if the needle of the dial gauge moves more than 10 μm, the position of the tool electrode needs to be adjusted by the second adjustment unit;

[0301] Among them, when the micrometer moves to the right, if the needle moves clockwise, the tool electrode tilts in the clockwise direction. At this time, turn the angle adjustment bolt counterclockwise. If the needle moves counterclockwise, the tool electrode tilts in the counterclockwise direction. At this time, turn the angle adjustment bolt clockwise.

[0302] Among them, the micrometer is controlled by the machine tool to move in the X, Y, and Z directions, and the moving time and speed of the micrometer are recorded to obtain the inclination angles of the tool electrode in the X, Y, and Z directions. Among them, in the YZ plane direction of the machine tool, the tool electrode is aligned with the micrometer, and the moving time of the micrometer is recorded as t1, the speed is v1, and the distance that the pointer of the micrometer rotates clockwise is S; if 0μm < S < 10μm, at this time, there is no need to adjust the rotation angle adjustment bolt; if S > 10μm, at this time, it is necessary to adjust the rotation angle adjustment bolt counterclockwise. Taking the center of the rotating body as the center of the circle, the angle β pushed by the rotation angle adjustment bolt satisfies:

[0303]

[0304] Among them, when it is necessary to push the rotation angle adjustment bolt counterclockwise, first rotate the rotation angle adjustment bolt counterclockwise so that the rotation angle adjustment bolt is movably connected to the first connecting body, and then push the rotation angle adjustment bolt counterclockwise with a pushing angle of -β. During this process, adjust according to the scale at the notch of the first connecting body, and the tool electrode can be aligned in the YZ plane direction of the machine tool. After the alignment is completed, rotate the rotation angle adjustment bolt clockwise to press it on the end face of the first connecting body to prevent the rotation angle adjustment bolt from sliding.

[0305] In this way, the alignment process of the tool electrode is realized.

[0306] Step 2: Clamp the stainless steel pipe 6 with the loading component and align the stainless steel pipe 6;

[0307] Specifically, first fix two equal-height positioning blocks 3 and two auxiliary support blocks 4 on the workbench 9, use a micrometer to align its side surface parallel to the X-axis of the machine tool, and use the machine tool to adjust the positions of the equal-height positioning blocks 3 and the auxiliary loading blocks 4, where the parallelism error ≤ 0.01mm.

[0308] Then place the stainless steel pipe 6 on the equal-height positioning blocks 3. Before placing, pass the stainless steel pipe 6 through the inner circular end at the lower end of the tool electrode 1, and ensure that the stainless steel pipe 6 is in a horizontal position through the equal-height positioning blocks 3. The distance between the two equal-height positioning blocks 3 is 30mm;

[0309] Next, place both ends of the stainless steel pipe 6 on the auxiliary support blocks 4, and finally fix it with the clamping plate 5.

[0310] Step 3: Use the machine tool to adjust the center line of the discharge end 101 of the tool electrode 1 to coincide with the inner cavity central axis of the stainless steel pipe 6;

[0311] Specifically, first adjust the position of the stainless steel pipe 6 by moving the loading component in the X-axis direction of the machine tool so that the position to be machined of the stainless steel 6 is located inside the discharge end 101 of the tool electrode 1;

[0312] Next, the automatic centering module of the machine tool is used to measure S 11 , S 12 , S 13 , S 14 If the four values ​​are equal or the error is within ±0.02mm, the center of the discharge end 101 of the tool electrode 1 coincides with the central axis of the inner cavity of the stainless steel tube 6. If they do not coincide, the position of the bearing assembly is continuously adjusted through the machine tool until it meets the requirements.

[0313] Step 4: Using kerosene and water as working fluid, perform electrospark machining on the stainless steel pipe 6 using the tool electrode 1 in the working fluid.

[0314] S101: Controlling the discharge end 101 of the tool electrode 1 to move eccentrically around the central axis of the inner cavity of the stainless steel tube 6;

[0315] Specifically, the machine tool drives the transmission rod 2 to swing in the YZ plane, and then controls the discharge end 101 of the tool electrode 1 to perform eccentric movement around the inner axis of the stainless steel tube 6 through the transmission rod 2; the eccentric movement direction 8 is as follows: Fig.10 shown.

[0316] Among them, the swing speed of the transmission rod 2 is 0.5rpm;

[0317] S 11 , S 12 , S 13 , S 14 The actual measured values ​​are 2.055mm, 2.060mm, 2.065mm, and 2.050mm respectively. At this time, S1 = 2.058mm;

[0318] The machining gap S2 is 10 μm;

[0319] Single-side feed O1O2 = S1 + (H1-H2) - S2 = 2.058 + (0.5-0.3) - 0.01 = 2.248 mm;

[0320] The processing speed is 0.04 g / min.

[0321] S102: When the tool electrode 1 performs eccentric motion, power is supplied to the tool electrode 1 to perform electrical discharge machining.

[0322] Specifically, the electrical parameters meet the following requirements:

[0323] Pulse width 40μs, pulse interval 26μs, average machining current 1A, average machining voltage 40V.

[0324] After the processing is completed, the damaged discharge parts are replaced to reduce the impact on the processing accuracy.

[0325] In this way, the discharge end of the tool electrode eccentrically moves around the central axis of the inner cavity of the stainless steel pipe for one circle, so as to complete the processing of the broken groove of the stainless steel pipe, achieve one-time processing and significantly improve the processing efficiency.

[0326] The above processing method was used to process the fracture grooves of #01-#10 ultra-slender stainless steel pipes, and the processing parameters are shown in Table 1 below.

[0327] Table 1 Processing parameters

[0328]

[0329] Processing requirements: The wall thickness of the fracture groove is 0.3±0.05mm and the bevel angle α is 90°.

[0330] The test results are shown in Table 2 below.

[0331] Table 2 Test results

[0332]

[0333] The electrode consumption ratio is E / W*100%, where E is the change in the diameter size of the discharge end of the tool electrode, and W is the initial diameter size of the inner circle end of the tool electrode.

[0334] It can be seen from Table 2 that the average depth of the fracture grooves of the 10 stainless steel tubes processed by the present invention is 0.2146 mm, the standard deviation is 0.01427, the dispersion coefficient is 0.07, the fracture groove angles are all 90°, the average fracture groove wall thickness is 0.299 mm, the standard deviation is 0.006681, and the dispersion coefficient is 0.02. It can be seen that the processing method of the present invention can realize the processing of the fracture groove of the ultra-slender stainless steel tube, and the processed fracture groove is high in precision and stable, will not damage the ultra-slender stainless steel tube, and has little loss to the tool electrode.

[0335] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0336] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for processing an annular groove, characterized in that: An assembled electrode is used, wherein the assembled electrode comprises: A conductive member and a discharge member electrically connected to the conductive member, wherein the discharge member is sleeved on the workpiece to be processed and moves eccentrically around the workpiece to be processed to realize the electric spark processing of the annular groove of the workpiece to be processed, and the workpiece to be processed remains stationary during the processing; The processing direction is a circumferential direction around the outer end surface of the workpiece to be processed, and the center line of the circumferential direction coincides with the center axis of the inner cavity of the workpiece to be processed; Wherein, the discharge end of the discharge member matches the shape of the annular groove, and the discharge member is detachably connected to the conductive member; The discharge member includes a plurality of electric spark machining points arranged circumferentially around the workpiece to be machined; Wherein, during the process of EDM machining by eccentric motion of the discharge member around the workpiece to be machined, the same EDM machining point includes a working state and a non-working state; The machining of the annular groove on the surface to be machined is achieved through the working state of a plurality of electrospark machining points arranged circumferentially around the workpiece to be machined.

2. The processing method according to claim 1, characterized in that: The conductive member comprises a conductive rod, one end of which is a conductive end and is clamped on a universally adjustable clamp, and the other end of which is electrically connected to the discharge member.

3. The processing method according to claim 2, characterized in that: The electrode comprises a plurality of limiting plates and clamping members for fixing the limiting plates, and the plurality of limiting plates surround a clamping space for fixing and connecting one end of the conductive rod and the discharge member.

4. The processing method according to claim 2, characterized in that: The discharge member is a circular ring structure, one end of the conductive rod is provided with a step hole coaxial with the discharge member, and the discharge member is detachably coaxially installed in the step hole of the conductive rod.

5. The processing method according to claim 2, characterized in that: The outer circular end of the discharge member is a mounting end, and one end of the conductive rod is a circular ring-shaped end, on which a stepped through-hole-shaped groove for placing the mounting end is provided, the mounting end is stuck in the groove, and the discharge member is electrically connected to the conductive rod through its mounting end; Wherein, a circular ring-shaped limiting plate is also provided on the circular ring-shaped end of the conductive rod, and the circular ring-shaped limiting plate is fixedly mounted on the conductive rod by bolts to press the mounting end of the discharge member into the groove.

6. The processing method according to claim 5, characterized in that: The discharge member is a continuous annular structure, and the inner diameter of the annular discharge member is smaller than the inner diameter of the annular end of the conductive rod.

7. The processing method according to claim 5, characterized in that: The discharge member includes a plurality of fan-shaped discharge portions, and the plurality of fan-shaped discharge portions form the annular discharge member; Wherein, a plurality of the fan-shaped discharge portions are electrically connected; The inner diameter of the discharge member is smaller than the inner diameter of the annular end of the conductive rod.

8. The processing method according to claim 7, characterized in that: The annular limiting plate includes a plurality of sector-shaped limiting plates, and the plurality of sector-shaped limiting plates form the annular limiting plate; Wherein, the plurality of fan-shaped limiting plates are respectively used to press the plurality of fan-shaped discharge portions onto the annular end of the conductive rod.

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