A machining method for a V-shaped groove of an ultra-fine long thin-walled pipe

Abstract

The application relates to a processing method of a V-shaped groove of an ultra-fine long thin-wall pipe, and belongs to the technical field of ultra-fine long pipe processing, which solves the problem that it is difficult to realize high-precision processing of the V-shaped groove on the ultra-fine long thin-wall pipe in the prior art. The method comprises the following steps: aligning a tool electrode by using a universal adjustable clamp; clamping the thin-wall pipe by using a bearing assembly and aligning the thin-wall pipe; and realizing processing of the V-shaped groove on a to-be-processed surface by using the working state of a plurality of electric spark processing point positions of the tool electrode which are arranged in the circumferential direction of the thin-wall pipe; wherein the same electric spark processing point position comprises a working state and a non-working state. The V-shaped groove of the ultra-fine long thin-wall pipe is processed with high precision, and the processing can be completed at one time, so that the processing efficiency is obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-long pipe machining, and particularly relates to a machining method of a V-shaped groove of an ultra-long thin-wall pipe. BACKGROUND

[0002] A V-shaped groove needs to be machined on some ultra-long flight products. Since the ultra-long flight products have the characteristics of small diameter and thin wall, the size of the V-shaped groove machined thereon is smaller. For the flight products whose size control is crucial, the machining precision requirement of the V-shaped groove puts forward higher requirements on the machining method.

[0003] It is difficult to meet the machining precision requirement of the V-shaped groove by using the traditional turning machining method. This is because the part clamping and the application of cutting force in the turning machining will inevitably affect the machining precision of the V-shaped groove.

[0004] Therefore, in order to meet the machining requirement of the V-shaped groove on the ultra-long flight product, a new machining method of the V-shaped groove needs to be explored. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide a machining method of a V-shaped groove of an ultra-long thin-wall pipe, so as to solve the problem that the high-precision machining of the V-shaped groove on the ultra-long thin-wall pipe is difficult to be realized.

[0006] In one aspect, the embodiments of the present application provide a machining method of a V-shaped groove of an ultra-long thin-wall pipe, comprising the following steps:

[0007] comprising the following steps:

[0008] Step 1: aligning the tool electrode by using the universal adjustable clamp;

[0009] Step 2: clamping the thin-wall pipe by using the bearing assembly and aligning the thin-wall pipe;

[0010] Step 3: realizing the machining of the V-shaped groove on the machined surface by using the working state of the plurality of circumferentially arranged electric spark machining points of the tool electrode around the thin-wall pipe;

[0011] Wherein, the same electric spark machining point is in the working state or the non-working state by changing the distance between the electric spark machining point and the machined surface.

[0012] Based on the further improvement of the above method, the universal adjustable clamp comprises a clamping part for clamping the tool electrode, a first adjusting part for aligning the tool electrode on the XY plane of the machine tool, and a second adjusting part for aligning the tool electrode on the YZ plane of the machine tool.

[0013] Wherein, the clamping part comprises a reference seat, a clamping seat mounted on the reference seat, and a fastening screw for adjusting the clamping force of the tool electrode.

[0014] The first adjusting part comprises upper and lower distributed first and second fixing bases, the second fixing base is installed at the lower end of the first fixing base through a plurality of vertical screws, and the clamping part is installed at the lower end of the second fixing base;

[0015] The second adjusting part comprises a clamp head installed on the machine tool, a first connecting body fixedly connected with the clamp head, a rotating body rotatably connected with the first connecting body in the horizontal direction, and a second connecting body fixedly connected with the rotating body; the second connecting body is connected with the first fixing base;

[0016] One end of the rotating body is provided with a rotation angle adjusting screw, one end of the rotation angle adjusting screw is screwed on the rotating body; and an angle value scale surface is arranged on the end surface of the first connecting body.

[0017] Based on the further improvement of the above method, the step 1 comprises:

[0018] S11: clamping the tool electrode by the clamping part of the universal adjustable clamp, and pressing the tool electrode by the fastening screw;

[0019] S12: adjusting the up and down space positions of the vertical screws in the XY plane direction of the machine tool to adjust the inclination angle of the second fixing base in the horizontal direction;

[0020] S13: adjusting the position of the rotating body in the horizontal plane in the YZ plane direction of the machine tool to adjust the inclination angle of the tool electrode in the YZ plane of the machine tool.

[0021] Based on the further improvement of the above method, the step S13 comprises:

[0022] S131: in the YZ plane direction of the machine tool, taking the discharge end surface of the tool electrode as a reference surface, moving the reference surface along the Y axis direction of the machine tool by using the dial gauge to align the tool electrode;

[0023] S132: pushing the rotation angle adjusting screw to drive the rotating body to rotate through the rotation angle adjusting screw to adjust the inclination angle of the tool electrode in the YZ plane of the machine tool.

[0024] Based on the further improvement of the above method, in step S132, taking the scale surface arranged on the end surface of the first connecting body as a reference surface, pushing the rotation angle adjusting screw, and the pushing angle is β;

[0025] Wherein, taking the center of the rotating body as the center, the pushing angle β of the rotation angle adjusting screw satisfies:

[0026]

[0027] Wherein, S is the distance of the dial needle of the dial gauge when detecting the tilt angle of the tool electrode in the YZ plane direction of the machine tool; v1 is the speed of the dial gauge moving; t1 is the time of the dial gauge moving.

[0028] Based on the further improvement of the above method, the center line of the discharge end of the tool electrode is parallel to the upper and lower end faces of the second fixed seat, and the tool electrode moves synchronously when adjusting the second fixed seat.

[0029] Based on the further improvement of the above method, one end of the tool electrode is a discharge end, and the discharge end includes a plurality of electric spark machining point positions arranged circumferentially around the thin-walled tube. During machining, the plurality of electric spark machining point positions arranged circumferentially around the thin-walled tube form a continuous circular ring, and the inner circle end of the circular ring matches the shape of the V-shaped groove.

[0030] Wherein, the discharge end of the tool electrode is sleeved on the thin-walled tube, and during machining, the discharge end of the tool electrode moves eccentrically around the central axis of the inner cavity of the thin-walled tube.

[0031] Based on the further improvement of the above method, when the discharge end of the tool electrode moves eccentrically around the central axis of the inner cavity of the thin-walled tube during machining, the single-sided feed amount O1O2 satisfies:

[0032] O1O2=S1+(H1-H2)-S2

[0033] Wherein, H1 is the wall thickness of the thin-walled tube; H2 is the wall thickness of the V-shaped groove; S1 is the distance between the discharge end of the tool electrode and the surface to be machined before machining; and S2 is the machining gap.

[0034] Based on the further improvement of the above method, the discharge end of the tool electrode is driven to move eccentrically around the central axis of the inner cavity of the thin-walled tube by the driving assembly.

[0035] Wherein, the non-electric parameters satisfy:

[0036] The swing speed of the driving assembly is 0.4-0.6 rpm, the machining gap is 10-50 μm, and the machining speed is 0.02-0.045 g / min.

[0037] Wherein, the electric parameters satisfy:

[0038] The pulse width is 30-60 μs, the pulse interval is 20-30 μs, the average machining current is 0.8-2 A, and the average machining voltage is 30-60 V.

[0039] Based on the further improvement of the above method, the step 2 includes:

[0040] S21: fixing the bearing assembly on the workbench of the machine tool and aligning it by the machine tool;

[0041] S22: pass the thin-walled tube through the discharge end of the tool electrode, and clamp the thin-walled tube by using the bearing assembly;

[0042] S23: adjust the bearing assembly by the machine tool to drive the thin-walled tube to move until the axis in the inner cavity of the thin-walled tube coincides with the center line of the discharge end of the tool electrode.

[0043] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0044] 1、The first adjusting part of the universal adjustable clamp is used for adjusting the inclination angle of the tool electrode in the horizontal plane; the inclination angle of the tool electrode in the YZ plane of the machine tool is determined according to the detection value of the dial gauge and the time and speed of the dial gauge movement, and the inclination angle of the tool electrode in the YZ plane of the machine tool is adjusted to the corresponding scale of the angle scale on the first connecting body by driving the corner adjusting bolt, so that the tool electrode is aligned, the operation is convenient, and the machining efficiency and precision are improved.

[0045] 2、During machining, only the superfine long thin-walled tube needs to be placed in the V-shaped groove on the equal-height positioning block and the auxiliary bearing block, and the upper surface of the superfine long thin-walled tube is limited by the clamping plate, so that the superfine long thin-walled tube can be clamped and positioned, the clamping is convenient, and the stability of the superfine long thin-walled tube during machining can be ensured.

[0046] 3、The discharge end of the tool electrode is in the shape of a circular ring, which is eccentrically moved on the outer end surface of the superfine long thin-walled tube, and the distance between the end surface of the discharge end and the machined end surface of the superfine long thin-walled tube changes constantly during the movement, the working end is closer to the superfine long thin-walled tube, and the non-working end is farther away from the superfine long thin-walled tube, so that the outer end surface of the superfine long thin-walled tube is machined by the working end; along the machining direction, the position of the working end changes constantly on the inner circular end surface of the discharge end, that is, when the inner circular end surface of the discharge end is close to the outer end surface of the superfine long thin-walled tube, the end surface of the discharge end is the working end, and when the end surface is far away from the outer end surface of the superfine long thin-walled tube, the end surface changes to the non-working end, so that the working end and the non-working end change dynamically, the working end of the tool electrode is prevented from being in a continuous machining state, the wear of the working end of the tool electrode is greatly reduced, the tool electrode wear is less than or equal to 1%, and the deformation of the working end surface of the tool electrode is reduced, so that the machining precision of the V-shaped groove of the superfine long thin-walled tube is improved.

[0047] 4. The discharge end of the tool electrode of the present invention is fitted onto the ultra-thin thin-walled tube and moves eccentrically. During processing, the distance between the discharge end and the ultra-thin thin-walled tube decreases and then increases. During the process of decreasing distance, metal debris is generated between the discharge end and the thin-walled tube. At this time, some of the metal debris will be discharged with the working fluid through the processing gap. During the process of increasing distance, the distance between the discharge end and the thin-walled tube can increase by nearly 200 times, which significantly improves the efficiency of metal debris discharge. This avoids the accumulation of metal debris at the discharge end due to untimely discharge, thereby reducing the wear of the tool electrode and avoiding the risk of short circuit caused by the tool electrode directly connecting to the thin-walled tube through metal debris.

[0048] 5. By making eccentric movements on the ultra-thin and long thin-walled tube through the discharge end of the tool electrode, metal chips can be efficiently discharged, thereby enabling electrical discharge machining with a smaller machining gap. This reduces the machining current and voltage, lowers machining costs, and produces V-grooves with low surface roughness.

[0049] 6. By adjusting the value of the single-sided feed, V-grooves with different wall thicknesses can be processed. By adjusting the shape of the discharge end of the tool electrode, different angles α can be processed, laying the foundation for rapid production and mass production of products.

[0050] 7. The tool electrode of the present invention can complete the processing of the fracture groove of the ultra-thin stainless steel tube by moving eccentrically around the central axis of the inner cavity of the tube for one revolution, achieving one-time processing and significantly improving processing efficiency.

[0051] 8. This invention abandons the traditional turning process for ultra-thin stainless steel tubes. It uses the working end of the tool electrode to discharge and erode the metal on the surface of the ultra-thin stainless steel tube to perform the fracture groove processing. That is, during the processing, the tool electrode does not contact the surface of the ultra-thin stainless steel tube, so it will not cause deformation and overcomes the problem of damage to the ultra-thin stainless steel tube by cutting force.

[0052] 9. This invention utilizes the eccentric movement of the discharge end of the tool electrode around the central axis of the inner cavity of the ultra-thin stainless steel tube to process the fracture groove of the ultra-thin stainless steel tube. That is, during the processing, the ultra-thin stainless steel tube does not need to rotate, and a ring-shaped fracture groove can be processed on its outer surface. This overcomes the problem that the coaxiality of the ultra-thin stainless steel tube deteriorates during rotation, which affects the processing accuracy.

[0053] 10. By eccentrically moving the discharge end of the tool electrode around the central axis of the inner cavity of the stainless steel tube, the single-sided feed amount of each end face at the discharge end can be made the same, ensuring the consistency of the processing depth of the break groove, thereby improving the processing accuracy of the break groove.

[0054] The technical solutions in the present application can be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the following description, and some advantages will become apparent from the description, or will be understood by those skilled in the art through implementation of the present application. The objects and other advantages of the present application can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0055] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0056] Figure 1 The machining method flow chart of the ultra-fine long and thin-wall pipe V-shaped groove of the present application;

[0057] Figure 2 The schematic diagram of the tool electrode structure of the present application;

[0058] Figure 3 The schematic diagram of the overall structure of the universal adjustable clamp of the present application;

[0059] Figure 4 The schematic diagram of the cross-section of the universal adjustable clamp of the present application;

[0060] Figure 5 The schematic diagram of the adapter adjusting bolt and the first connecting body cooperation structure of the present application;

[0061] Figure 6 The schematic diagram of the cross-section at A-A in the present application; Figure 2 The schematic diagram of the cross-section at A-A in the present application;

[0062] Figure 7 The schematic diagram of the structure when the center line of the discharge end of the tool electrode of the present application coincides with the central axis of the inner cavity of the stainless steel pipe;

[0063] Figure 8 The schematic diagram of the structure when the center line of the tool electrode of the present application deviates from the central axis of the inner cavity of the stainless steel pipe;

[0064] Figure 9 The schematic diagram of the cross-section when the discharge end sleeve of the tool electrode of the present application is on the stainless steel pipe;

[0065] Figure 10 The schematic diagram of the movement trajectory of the center point O2 of the discharge end when the discharge end of the tool electrode of the present application moves eccentrically around the central axis of the inner cavity of the stainless steel pipe;

[0066] Figure 11 The schematic diagram of the movement trajectory of any point O3 on the discharge end when the discharge end of the tool electrode of the present application moves eccentrically around the central axis of the inner cavity of the stainless steel pipe;

[0067] Figure 12 Fig. 1 is a schematic view of the structure of the stainless steel pipe breaking groove in the present application;

[0068] Figure 13 Fig. 2 is a schematic view of the cooperation structure of the bearing assembly and the stainless steel pipe in the present application;

[0069] Figure 14 Fig. 3 is a schematic view of the cooperation structure of the equal-height positioning block, the clamping plate and the stainless steel pipe in the present application;

[0070] Figure 15 Fig. 4 is a schematic view of the cooperation structure of the auxiliary bearing block and the stainless steel pipe in the present application;

[0071] Figure 16 Fig. 5 is a schematic view of the stainless steel pipe breaking groove after processing in the present application.

[0072] Reference signs:

[0073] 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 - processing direction; 8 - eccentric movement direction; 9 - machine tool workbench; 10 - reference seat; 11 - clamping seat; 12 - fastening screw; 13 - first fixed seat; 14 - second fixed seat; 15 - vertical screw; 16 - insulating plate; 17 - clamp head; 18 - first connecting body; 19 - second connecting body; 20 - rotating body; 21 - angle adjusting bolt; 22 - notch; 23 - movement direction of the dial gauge on the discharge end face of the tool electrode along the Z-axis direction of the machine tool; 24 - movement direction of the dial gauge on the discharge end face of the tool electrode along the Y-axis direction of the machine tool; H1 - wall thickness of the stainless steel pipe; H2 - wall thickness of the breaking groove; a - breaking groove oblique angle; S 11 , S 12 , S 13 , S 14 - actual excess gap value between the four points selected on the circular working end of the tool electrode and the outer end face of the stainless steel pipe; S2 - processing gap; O1 - center point of the discharge end; O2 - center point of the inner cavity of the stainless steel pipe; O3 - selected point on the discharge end. DETAILED DESCRIPTION

[0074] The preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings constitute a part of this application and serve to explain the principles of the embodiments of the present application, but are not used to limit the scope of the present application.

[0075] The ratio of diameter to length is 1:100-150, which belongs to super thin long shaft. For example, the outer diameter of stainless steel pipe used in some aviation products is 2mm, the inner diameter is 1mm, and the length is 1-1.2m. The ratio of outer diameter to length of the stainless steel pipe is 1:500-600, which belongs to super thin long stainless steel pipe. When processing, a V-shaped groove is generally needed on the super thin long steel pipe. The V-shaped groove is a breaking groove, which is used to separate the product fairing body from the product guidance system when the product reaches the predetermined height and position.

[0076] Because the diameter of the super thin stainless steel pipe is small, the wall thickness is thin, and the wall thickness at the breaking groove position is even thinner, such as 0.3±0.05mm, the important dimension cannot be obtained by direct measurement. When the breaking groove is processed at a certain position of the super thin long stainless steel pipe, it is difficult to ensure the wall thickness dimension at the breaking groove position by using the traditional turning processing method. This is because the longer the length is, the greater the centrifugal force of the workpiece during rotation will be, and the worse the coaxiality of the workpiece will be. In addition, the cutting force generated is easy to cause deformation of the super thin long stainless steel pipe.

[0077] To solve the above problems, the present application provides a processing method for V-shaped groove of super thin long thin-walled pipe, comprising the steps of:

[0078] Step 1: aligning the tool electrode with the universal adjustable clamp;

[0079] Step 2: clamping the thin-walled pipe with the bearing assembly and aligning the thin-walled pipe;

[0080] Step 3: using the working state of the plurality of circumferentially arranged electric spark machining points of the tool electrode to realize the processing of the V-shaped groove on the surface to be processed;

[0081] Wherein, by changing the distance between the electric spark machining point and the surface to be processed, the same electric spark machining point is in working state or non-working state.

[0082] Specifically, one end of the tool electrode 1 is a discharge end 101, and the discharge end 101 comprises a plurality of circumferentially arranged electric spark machining points;

[0083] When the distance between the electric spark machining point and the surface to be processed is greater than the threshold value, the electric spark machining point is in non-working state;

[0084] When the distance between the electric spark machining point and the surface to be processed is less than or equal to the threshold value, the electric spark machining point is in working state;

[0085] The threshold value is the discharge distance between the electric spark machining point and the surface to be processed that meets the processing requirements.

[0086] It is understandable that the discharge end 101 includes multiple electrical discharge machining points arranged around the circumference of the thin-walled tube. These multiple electrical discharge machining points can be continuously and uninterruptedly distributed around the circumference of the thin-walled tube, or they can be discontinuously distributed around the circumference of the thin-walled tube, as long as they can achieve continuous machining and forming of V-shaped grooves on the surface to be machined.

[0087] In one possible implementation, one end of the tool electrode 1 is annular, meaning that multiple electrical discharge machining points arranged circumferentially around the thin-walled tube form a continuous annular shape, such as... Figures 6-9 As shown, the inner circle of the ring matches the shape of the V-groove, that is, the inner circle is convex and the V-groove is concave. The cross-sectional dimensions of the convex shape are the same as the cross-sectional shape of the concave shape. 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 installed on the machine tool to introduce current and transmit the current to the inner circle. At this time, the inner circle is a discharge end 101, so that the V-groove on the surface to be processed can be realized through the working state of multiple electrical discharge machining points arranged around the thin-walled tube through the discharge end 101.

[0088] In one possible implementation, the discharge end is a rigid structure, with the discharge end 101 fitted onto the outer end face of the stainless steel tube 6. During processing, the stainless steel tube 6 is electrically connected to another 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. 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 of the stainless steel tube 6 to be processed continuously changes. When the distance between the electrical discharge machining point and the surface to be processed is greater than a threshold, the electrical discharge machining point is in a non-working state; at this time, the electrical discharge machining point is the non-working end 103. When the distance between the electrical discharge machining point and the surface to be processed is less than or equal to a threshold, the electrical discharge machining point is in a non-working state. When the threshold is reached, the electrical discharge machining (EDM) point is in the working state. At this time, the EDM point is the working end 102. In this way, the transition between the working state and the non-working state is realized at the same EDM point. The working states of all EDM points together realize the machining of the fracture groove on the surface to be machined. That is to say, the position of the working end 102 is constantly changing within the inner circular end face of the discharge end 101. The circular discharge end of the tool electrode moves eccentrically around the central axis of the inner cavity of the stainless steel tube. All the working ends form a continuous circular discharge end around the circumference of the stainless steel tube. In this way, the discharge end 101 of the tool electrode 1 is avoided from being in a continuous machining state, thereby reducing the wear of the tool electrode 1.

[0089] Among them, the annular discharge end 101 of the tool electrode 1 includes several working ends 102 distributed in a ring. When the discharge end moves eccentrically around the central axis of the inner cavity of the stainless steel tube 6 for processing, the several working ends 102 are in a non-synchronous and non-continuous processing state; and the processing trajectory of the several working ends together constitutes the break groove of the stainless steel tube 6.

[0090] Wherein, after the eccentric movement of the tool electrode 1 for one cycle, all the end faces of the discharge end 101 participate in the electric spark machining, that is, all the working ends 102 constitute a complete discharge end 101, and the machining tracks of all the working ends 102 jointly constitute the breaking groove 601 of the super-thin long stainless steel pipe; along the machining direction 7, the working ends 102 present a "circumferential motion" phenomenon on the discharge end 101, that is, at different moments, the positions of the working ends 102 are different, so that all the working ends 102 alternately and orderly perform machining, the machining direction 7 is the circumferential direction around the outer end face of the stainless steel pipe 6, and the plane where the circumferential direction is located is perpendicular to the central axis in the inner cavity of the stainless steel pipe 6.

[0091] Compared with the prior art, the present application can conveniently align the tool electrode by using the universal adjustable clamp, and can align the thin-walled pipe by using the bearing assembly, so as to realize the coincidence of the central axis in the inner cavity of the thin-walled pipe and the center line of the discharge end of the tool electrode, so as to determine the value of the single-sided feed amount. At the same time, the discharge end of the tool electrode performs eccentric motion around the central axis in the inner cavity of the thin-walled pipe, so as to realize the equivalence of the single-sided feed amount of multiple electric spark machining points, thereby improving the machining precision of the V-shaped groove. In addition, the discharge end 101 of the tool electrode 1 is in the form of a circular ring, which is eccentrically moved on the outer end face of the stainless steel pipe 6. In this process, the distance between the end face of the discharge end 101 and the machined end face of the stainless steel pipe 6 is constantly changing. The closer distance is the working end 102, and the farther distance is the non-working end 103. The outer end face of the stainless steel pipe 6 is machined by the working end 102, and along the machining direction, the position of the working end 102 constantly changes in the inner circular end face of the discharge end 101. That is, when the inner circular end face of the discharge end 101 is close to the outer end face of the stainless steel pipe 6, the end face of the discharge end 101 is the working end 102, and when the end face is far away from the outer end face of the stainless steel pipe 6, the end face changes to the non-working end 103. The dynamic change between the working end 102 and the non-working end 103 is realized, so as to avoid the working end 102 of the tool electrode 1 in the continuous machining state, greatly reduce the loss of the working end of the tool electrode 1, realize the tool electrode loss ≤1%, and further reduce the deformation of the working end face of the tool electrode 1, so as to improve the machining precision of the breaking groove 601 of the super-thin long stainless steel pipe.

[0092] Wherein, the judgment basis of whether the discharge end 101 is the working end 102 is whether the distance between the discharge end 101 and the machined surface of the stainless steel pipe 6 is greater than 50μm. If not, the discharge end 101 is the working end 102, and if yes, the discharge end 101 is the non-working end 103.

[0093] Wherein, the plane where the tracks simultaneously moving in the X-axis direction and the Y-axis direction of the machine tool are located is the XY plane, that is, the horizontal plane; the plane where the tracks simultaneously moving in the Y-axis direction and the Z-axis direction of the machine tool are located is the YZ plane.

[0094] Specifically, step 1 above includes the following steps:

[0095] S11: The tool electrode 1 is clamped using the clamping part of the universal adjustable clamp, and the tool electrode 1 is pressed tightly using the fastening screw 12;

[0096] S12: Adjust the upper and lower spatial positions of the vertical screw 15 in the XY plane of the machine tool to adjust the tilt angle of the second fixed seat 14 in the horizontal direction.

[0097] S13: Adjust the position of the rotating body 20 on the horizontal plane in the YZ plane of the machine tool to adjust the tilt angle of the tool electrode 1 on the YZ plane of the machine tool.

[0098] In S11, the clamping part of the universal adjustable clamp includes a reference base 10 and a clamping seat 11 mounted on the reference base 10, wherein, as Figures 3-4 As shown, the space between the adjacent surfaces of the clamping base 11 and the reference base 10 is a clamping space for mounting the tool electrode 1. During installation, the upper end of the tool electrode 1 is installed in this clamping space to clamp the tool electrode 1. The clamping part also includes a fastening screw 12 for adjusting the clamping force on the tool electrode 1. The fastening screw 12 is screwed onto the clamping base 11, with one end passing through the clamping base 11 and located in the clamping space. During installation, after placing the upper end of the tool electrode 1 in the clamping space, the fastening screw 12 is rotated to press against the end face of the tool electrode 1, thereby pressing the tool electrode 1 firmly and preventing it from slipping.

[0099] Furthermore, the inner end face of the clamping space that connects with the tool electrode 1 is a V-shaped surface, and the upper end face of the tool electrode 1 is adapted to this V-shaped surface. The angle of this V-shaped surface is 90° to prevent the tool electrode 1 from sliding in the horizontal direction during the clamping process of the fastening screw 12. This achieves the clamping of the tool electrode 1.

[0100] Specifically, in S12, the tilt angle of the tool electrode 1 in the XY plane is adjusted using the first adjustment part of the universal adjustable clamp. The first adjustment part includes a first fixed seat 13 and a second fixed seat 14 distributed vertically. The second fixed seat 14 is mounted on the lower end of the first fixed seat 13 by a vertical screw 15, and a gap is provided between the adjacent surfaces of the first fixed seat 13 and the second fixed seat 14. One end of the vertical screw 15 passes through the first fixed seat 13 and the second fixed seat 14, and is screwed to the first fixed seat 13 and slidably connected to the second fixed seat 14. A nut is provided at the bottom of the vertical screw 15 to limit the second fixed seat 14 in a direction perpendicular to it, so that the tilt angle of the second fixed seat 14 in the XY direction can be adjusted by rotating the vertical screw 15.

[0101] Four vertical screws 15 are arranged on the first fixing base 13 vertically and uniformly, and the top of the four vertical screws 15 is a rotating head, which is convenient to rotate the vertical screw 15 by applying force from the rotating head. In the initial state, the rotating head of the vertical screw 15 is provided with the same clearance gap with the upper end surface of the first fixing base 13, so as to ensure that the vertical screw 15 has enough space to rotate.

[0102] Further, the second fixing base 14 is fixedly installed with an insulating plate 16 at the lower end, and the reference base 10 is fixedly connected with the lower end surface of the insulating plate 16. In this way, when the inclination angle of the second fixing base 14 in the horizontal direction is adjusted, the tool electrode 1 can be aligned in the vertical direction, and the insulating plate 16 can prevent the operator from being electrified.

[0103] For example, the vertical screw 15 at the left end of the first fixing base 13 is rotated clockwise, and then the left end of the second fixing base 14 is inclined downward under the action of the vertical screw 15. At this time, the second fixing base 14 drives the reference base 10 to move synchronously through the insulating plate 16, and then drives the lower end of the tool electrode 1 to incline to the right. In this way, rotating any vertical screw 15 can realize local adjustment of the second fixing base 14 in the Z-axis direction, and can realize adjustment of the inclination angle of the second fixing base 14 in the XY direction, and then realize adjustment of the inclination angle of the tool electrode in the XY direction.

[0104] Specifically, in S13, the second adjusting part of the universal adjustable clamp is used to adjust the inclination angle of the tool electrode 1 in the YZ direction of the machine tool. Figures 3-5 As shown in the figure, the second adjusting part includes a clamp head 17, a first connecting body 18, a second connecting body 19 and a rotating body 20. The clamp head 17 is installed on the machine tool, the first connecting body 18 is fixedly connected with the clamp head 17, the rotating body 20 is located between the first connecting body 18 and the second connecting body 19, the upper end of the rotating body 20 is rotatably connected with the first connecting body 18 in the horizontal direction, the lower end of the rotating body 20 is fixedly connected with the second connecting body 19, and the lower end of the second connecting body 19 is fixedly connected with the top of the first fixing base 13. In this way, by rotating the rotating body 20 in the horizontal direction, the second connecting body 19 can be controlled to rotate in the horizontal plane, and then the position of the first fixing base 13 can be adjusted in the horizontal direction, and then the tool electrode 1 can be aligned in the YZ direction of the machine tool.

[0105] The lower end of the first connecting body 18 is provided with a cavity for placing the rotating body 20, the rotating body 20 is placed in the cavity, and the upper end of the rotating body 20 is rotatably installed on the top wall of the cavity; a corner adjusting screw 21 is installed at one end of the rotating body 20, one end of the corner adjusting screw 21 is screwed on the rotating body 20, and the other end thereof is located outside the first connecting body 18 through the cavity wall of the first connecting body 18; a slot 22 is provided on the side end face of the first connecting body 18, so that when the rotating body 20 rotates, the corner adjusting screw 21 can slide in the slot 22; the end of the corner adjusting screw 21 located outside the first connecting body 18 is a screw head, and by rotating the screw head, the corner adjusting screw 21 can be moved towards or away from the first connecting body, thereby adjusting the pressing force of the corner adjusting screw 21 on the first connecting body 18, and further adjusting the state of the rotating body 20.

[0106] For example, rotate the corner adjusting screw 21 counterclockwise until the pressing force of the corner adjusting screw 21 on the first connecting body 18 is eliminated, at this time, the rotating body 20 can rotate freely, and the rotating angle is limited by the length of the slot 22.

[0107] For example, rotate the corner adjusting screw 21 clockwise until the corner adjusting screw 21 is pressed on the end face of the first connecting body 18, at this time, the rotating body 20 cannot rotate.

[0108] Further, a rotating angle scale is provided in the length direction of the slot 22, wherein the middle part of the slot 22 where the corner adjusting screw 21 is located is 0°, when rotated clockwise, the maximum position of the corner adjusting screw 21 is 10°-30°, and when rotated counterclockwise, the maximum position of the corner adjusting screw 21 is -30°--10°, so as to realize accurate adjustment of the rotating angle of the rotating body 20, and further realize accurate adjustment of the tool electrode 1.

[0109] Wherein, the face provided with the scale on the end face of the first connecting body 18 is the reference face, the corner adjusting screw 21 is pushed to rotate, and the pushing angle is β;

[0110] Wherein, the center of the rotating body 20 is the center, and the pushing angle β of the corner adjusting screw 21 satisfies:

[0111]

[0112] Wherein, S: the dial gauge is moved in the Y-axis direction of the machine tool with the discharge end face of the tool electrode 1 as the reference face, and the moving distance of the dial gauge needle is S;

[0113] v1 is the speed of the dial gauge movement;

[0114] t1 is the time of the dial gauge movement.

[0115] In the process of aligning the tool electrode 1, the tool electrode 1 is set to a reference surface by using a dial gauge to align the tool electrode 1, and the universal adjustable clamp is adjusted so that the relative position error of the tool electrode and the three dimensions of the machine tool XYZ axis is ≤0.01mm.

[0116] Specifically, in step 2, the bearing assembly includes an equal-height positioning block 3 and an auxiliary bearing block 4 mounted 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.

[0117] Specifically, as shown in Figures 12-15 two equal-height positioning blocks 3 are provided, and the two equal-height positioning blocks 3 are respectively located on both sides of the to-be-processed position of the stainless steel pipe 6 to ensure the stability of the to-be-processed position of the stainless steel pipe 6 during processing. For example, the distance between the two equal-height positioning blocks 3 is 20-50mm.

[0118] Specifically, two auxiliary bearing blocks 4 are provided, and the two equal-height positioning blocks 3 are located between the two auxiliary bearing blocks 4 to support and position the two ends of the stainless steel pipe 6 through the two auxiliary bearing blocks 4, further ensuring the stability of the stainless steel pipe 6 during processing.

[0119] Wherein, the upper end faces of the equal-height positioning block 3 and the auxiliary bearing block 4 are flush, and the upper end faces 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 grooves to limit the stainless steel pipe 6.

[0120] Further, the equal-height positioning block 3 is also provided with a clamping plate 5, which 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. For example, the angle of the V-shaped groove is 60°-90°, and the depth is 5-10mm.

[0121] Wherein, before placing the stainless steel pipe 6 on the equal-height positioning block 3, the tool electrode 1 needs to be aligned by using the machine tool first, then the stainless steel pipe 6 is inserted into the discharge end 101 of the tool electrode 1, and finally the stainless steel pipe 6 is clamped by using the equal-height positioning block 3, the auxiliary bearing block 4 and the clamping plate 5, and the stainless steel pipe 6 is aligned by using the equal-height positioning block 3 and the auxiliary bearing block 4.

[0122] Specifically, after the tool electrode 1 is aligned, the positions of the equal-height positioning block 3 and the auxiliary bearing block 4 on the machine tool are adjusted by using the machine tool XYZ axis to align the stainless steel pipe 6, so that the center line of the inner cavity of the stainless steel pipe 6 coincides with the center line of the discharge end 101 of the tool electrode 1, so as to determine the value of the single-sided feed amount, and further improve the machining precision.

[0123] Wherein, the alignment process of the stainless steel pipe 6 is as follows.

[0124] First, first fix two equal height positioning block 3 and two auxiliary support block 4 on the worktable 9 of the machine tool, and then use the dial indicator to find the parallelism of the side surface and the machine tool X axis, the parallelism error is less than or equal to 0.01mm.

[0125] Before placing the stainless steel pipe 6 on the equal height positioning block 3, first pass the stainless steel pipe 6 into the discharge end 101 of the tool electrode 1, and then place the stainless steel pipe 6 on the equal height positioning block 3 and the auxiliary support block 4, in this way, the stainless steel pipe 6 is aligned through the equal height positioning block 3 and the auxiliary support block 4.

[0126] Specifically, in step 3, the tool electrode 1 is clamped in the clamping part, the reference seat 10 of the clamping part is connected with the driving assembly, the driving assembly includes a transmission rod 2, one end of the transmission rod 2 is connected with the reference seat 10, and is parallel to the center line of the discharge end 101 of the tool electrode 1; in the process of machining, the other end of the transmission rod 2 is installed on the machine tool, so as to drive the transmission rod 2 to swing through the machine tool, and then drive the tool electrode 1 and the universal adjustable clamp to move through the transmission rod 2, so as to realize the eccentric motion of the discharge end 101 of the tool electrode 1 around the central axis of the inner cavity of the stainless steel pipe 6, in this way, the discharge end 101 of the tool electrode 1 is surrounded around the end surface of the stainless steel pipe 6 to carry out electric spark machining, and the machining direction 7 is the circumferential direction around the outer end surface of the stainless steel pipe 6, and the center line of the circumferential direction coincides with the central axis of the inner cavity of the stainless steel pipe 6.

[0127] Specifically, before the eccentric motion of the tool electrode 1, it is necessary to adjust the center of the inner circular end of the discharge end 101 of the tool electrode 1 to coincide with the central axis of the stainless steel pipe 6, and there is a clearance gap between the discharge end 101 and the outer end surface of the stainless steel pipe 6, that is, the diameter of the inner circular end of the discharge end 101 is greater than the outer diameter of the stainless steel pipe 6, for example, the diameter of the inner circular end is 10-20mm, which is 5-10 times of the outer diameter of the stainless steel pipe 6. In this way, it is convenient to determine the value of the single-sided feed amount O1O2 in the process of electric spark machining.

[0128] Wherein, the single-sided feed amount O1O2 satisfies:

[0129] O1O2=S1+(H1-H2)-S2

[0130] Wherein, O1 represents the center point of the discharge end 101 of the tool electrode 1;

[0131] O2 represents the center point of the inner cavity of the stainless steel pipe 6;

[0132] H1 is the wall thickness of the stainless steel pipe 6;

[0133] H2 is the wall thickness of the breaking groove 601;

[0134] S1 indicates that there is a margin gap between the discharge terminal 101 and the outer end face of the stainless steel tube 6.

[0135] S2 is the machining clearance, which refers to the closest distance between the working end 102 and the end face of the stainless steel tube 601 when the tool electrode 1 moves eccentrically.

[0136] Wherein, S1 satisfies:

[0137]

[0138] Among them, such as Figure 7 As shown, S 11 S 12 S 13 S 14 The actual clearance value between four points selected on the discharge end 101 of the tool electrode 1 and the outer end face of the stainless steel tube 6 is given. These four points are evenly distributed on the discharge end 101.

[0139] For example, S 11 S 12 S 13 S 14 The corresponding values ​​are 2.055mm, 2.060mm, 2.065mm, and 2.050mm, respectively. At this time, S1 = 2.058mm.

[0140] The machining gap S2 is set to 10-50 μm to meet the requirements of electrical discharge machining.

[0141] For example, S2 = 10 μm; H1 = 0.5 mm, H2 = 0.3 mm, S1 = 2.058 mm, and O1O2 = 2.248 mm.

[0142] Among them, the automatic centering module on the machine tool can be used to measure S. 11 S 12 S 13 S 14 If the four values ​​are equal, the center of the inner circle 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.

[0143] Among them, after the center of the discharge end 101 of the machine tool adjustment tool electrode 1 is aligned with the central axis of the inner cavity 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 will be, and the more accurate the single-sided feed amount O1O2 will be. In this way, the accuracy of the machining gap can be ensured during the eccentric movement of the tool electrode 1, thereby ensuring the machining depth of the working end 102 and ensuring the dimensional accuracy of the machined break groove 601.

[0144] Specifically, after the center of the discharge end 101 of the tool electrode 1 coincides with the axis of the inner cavity of the stainless steel pipe 6, the tool electrode 1 is driven to perform eccentric motion by the machine tool, and the detailed process is described below.

[0145] The movement 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 pipe 6 are described as follows:

[0146] The tool electrode 1 is moved so that O1 is away from O2 by a distance equal to the single-side feeding amount O1O2, and at this time, the distance between O1 and O2 is O1O2.

[0147] O1 is rotated around O2 with O1O2 as the radius, and at this time, the trajectory of O1 is a circle, as shown in FIG. 4, the center of the circle is O2, and the radius is O1O2. Figure 10

[0148] During the movement of O1, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel pipe 6 reaches 10 μm, the power supply device is turned on to deliver pulse voltage to the tool electrode 1 and the stainless steel pipe 6, and the surface metal of the stainless steel pipe 6 is etched away at a machining speed of 0.04 g / min until the distance between O1 and O2 is O1O2, and then O1 performs circular motion around O2.

[0149] In order to further describe the movement trajectory of the tool electrode 1, an arbitrary point O3 on the discharge end 101 is selected, and the trajectory of O3 is described as follows:

[0150] The tool electrode 1 is moved so that O3 moves towards O2 by a distance O1O2.

[0151] When O1 rotates around O2, at this time, as shown in FIG. 5, the trajectory of O3 is a circle with the initial position of O3 as the center and O1O2 as the radius. Figure 11

[0152] 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 pipe 6 reaches 10 μm, the power supply device is turned on to deliver pulse voltage to the tool electrode 1 and the stainless steel pipe 6, and the surface metal of the stainless steel pipe 6 is etched away at a machining speed of 0.04 g / min until the movement distance of O3 reaches O1O2, and then O3 performs circular motion around the initial position thereof.

[0153] ​​In this way, during eccentric movement of the tool electrode 1, the distance between the inner circular end face of the discharge end 101 and the outer surface of the stainless steel pipe 6 is constantly changing, the distance between each part of the inner circular end face of the discharge end 101 and the outer end face of the stainless steel pipe 6 is achieved from close to far, and then the discharge end 101 is changed from the working state to the non-working state, that is, the dynamic change between the working end 102 and the non-working end 103 is achieved.

[0154] The discharge end 101 and the outer end face of the stainless steel pipe 601 have a clearance gap, which is used to ensure that the non-machining gap between the non-working end 103 at the discharge end 101 and the end face of the stainless steel pipe 6 is large enough, and then it is ensured that the pulse voltage released at the non-working end 103 cannot etch the metal on the surface of the stainless steel pipe 6. In this way, during eccentric movement of the tool electrode 1, the dynamic change between the working end 102 and the non-working end 103 can be achieved.

[0155] 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 pipe 6 is electrically connected to another output end of the power supply device. The power supply device includes a pulse power supply, and the two output ends are respectively connected to the positive and negative electrodes of the pulse power supply to output pulse voltage.

[0156] During machining, the discharge end 101 of the tool electrode 1 and the stainless steel pipe 6 are immersed in a liquid medium with a certain degree of insulation. For example, the medium is kerosene, mineral oil or deionized water. When the pulse voltage is applied to the discharge end 101 and the stainless steel pipe 6, the liquid medium between the closest points of the stainless steel pipe 6 and the discharge end 101 at that time is broken down to form a discharge channel. Because the cross-sectional area of the channel is very small, the discharge time is very short, so that the energy is highly concentrated (10 6 W / cm 2 The instantaneous high temperature generated in the discharge area is sufficient to melt or even evaporate the metal on the surface of the stainless steel pipe 6, so as to form a small pit. After the first pulse discharge ends, a second pulse breaks down the discharge at another closest point after a very short interval of time. In this way, the cycle is repeated at a high frequency, and the tool electrode 1 continuously feeds the stainless steel pipe 6. The shape of the tool electrode 1 is finally replicated on the stainless steel pipe 6 to form the required machined surface. During machining, although a small part of the total energy is also released to the tool electrode 1, causing the tool electrode 1 to be worn, by eccentric movement of the discharge end 101 of the tool electrode 1 around the central axis of the inner cavity of the stainless steel pipe 6, the working end 102 at the discharge end 101 is constantly changing position. In this way, by avoiding continuous machining of the working end 102, the wear of the tool electrode 1 is reduced, and then the working end 102 of the discharge end 101 maintains a relatively complete shape at each moment of machining, improving the machining precision.

[0157] For example, during machining, the electrical parameters satisfy:

[0158] The pulse width is 30-60 mu s, the pulse interval is 20-30 mu s, the average machining current is 0.8-2 A, and the average machining voltage is 30-60 V.

[0159] Specifically, during machining, the tool electrode 1 is controlled to eccentrically move by the machine tool, and the stainless steel pipe 6 remains stationary.

[0160] The tool electrode 1 is connected with a driving device arranged on the machine tool, and the driving device comprises a transmission rod 2. During machining, the machine tool controls the transmission rod 2 to swing, and the tool electrode 1 is driven to eccentrically move by the transmission rod 2.

[0161] Specifically, the transmission rod 2 swings clockwise in the swing plane YZ, and the swing plane YZ is parallel to the plane where the discharge end 101 is located. In this way, the tool electrode 1 is realized to eccentrically move around the central axis of the inner cavity of the stainless steel pipe 6.

[0162] Specifically, during machining, the non-electric parameters satisfy:

[0163] The swing speed of the driving assembly is 0.4-0.6 rpm, the machining gap is 10-50 mu m, and the machining speed is 0.02-0.045 g / min.

[0164] In this way, the discharge end 101 of the tool electrode 1 eccentrically moves around the central axis of the inner cavity of the stainless steel pipe 6 for one cycle, and the machining of the stainless steel pipe breaking groove 601 is completed, realizing one-time machining in place and significantly improving the machining efficiency.

[0165] In order to better utilize the above machining method to machine the V-shaped groove of the ultra-thin long and thin-walled pipe, the machining device is also provided. The machining device comprises a tool electrode 1 mounted on a machine tool, a universal adjustable clamp for aligning the tool electrode, a driving assembly for controlling the tool electrode to be in an eccentric motion state, and a bearing assembly for clamping the thin-walled pipe. In this way, the V-shaped groove of the ultra-thin long and thin-walled pipe is machined by the tool electrode 1 through electric spark machining, so as to solve the problem that the high-precision machining of the V-shaped groove on the ultra-thin long and thin-walled pipe is difficult to be realized.

[0166] One end of the tool electrode 1 is a discharge end 101, and the discharge end comprises a plurality of electric spark machining points arranged circumferentially around the thin-walled pipe. The same electric spark machining point comprises a working state and a non-working state.

[0167] When the distance between the electric spark machining point and the surface to be machined is greater than a threshold value, the electric spark machining point is in a non-working state.

[0168] When the distance between the electric spark machining point and the surface to be machined is less than or equal to the threshold value, the electric spark machining point is in a working state.

[0169] The threshold value is a discharge distance between the EDM point and the surface to be machined, which is 0-50 μm in an example.

[0170] The working state of the plurality of EDM points circumferentially arranged around the thin-walled tube realizes machining of the V-shaped groove on the surface to be machined.

[0171] It can be understood that the discharge end 101 includes a plurality of EDM points circumferentially arranged around the thin-walled tube, which can be continuously and uninterruptedly distributed circumferentially around the thin-walled tube or discontinuously distributed circumferentially around the thin-walled tube, and can realize continuous machining and forming of the V-shaped groove on the surface to be machined.

[0172] In a possible implementation, the tool electrode 1 has a circular ring shape at one end, that is, the plurality of EDM points circumferentially arranged around the thin-walled tube form a continuous circular ring shape, the inner circular end of the circular ring matches the shape of the V-shaped groove, that is, the inner circular end is convex, and the V-shaped groove is concave, and the cross-sectional size of the convex shape is the same as the cross-sectional shape of the concave shape; the other end of the tool electrode 1 is a conductive end 104 electrically connected to an output end of a power supply device arranged on a machine tool, for introducing current and transmitting the current to the inner circular end, at this time, the inner circular end is the discharge end 101, and the working state of the plurality of EDM points circumferentially arranged around the thin-walled tube of the discharge end 101 realizes machining of the V-shaped groove on the surface to be machined.

[0173] In a possible implementation, the discharge end has a rigid structure, and the discharge end 101 is sleeved on the outer end surface of the stainless steel tube 6; during machining, 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 surface of the discharge end 101 and the machined end surface of the stainless steel tube 6 is constantly changing; when the distance between the EDM point and the surface to be machined is greater than the threshold value, the EDM point is in a non-working state, at this time, the EDM point is a non-working end 103; when the distance between the EDM point and the surface to be machined is less than or equal to the threshold value, the EDM point is in a working state, at this time, the EDM point is a working end 102, so that the working state and the non-working state of the same EDM point are changed, and the working states of all the EDM points together realize machining of the breaking groove on the surface to be machined, that is, the position of the working end 102 constantly changes in the inner circular end surface of the discharge end 101, and the circular discharge end of the tool electrode moves eccentrically around the central axis of the inner cavity of the stainless steel tube for one revolution, and all the working ends circumferentially form a continuous circular ring-shaped discharge end around the stainless steel tube, so that the discharge end 101 of the tool electrode 1 is prevented from being in a continuous machining state, and the wear of the tool electrode 1 is reduced.

[0174] Wherein, in the process of eccentric motion of the tool electrode 1, the distance between the end face of the discharge end 101 and the end face to be machined of the stainless steel pipe 6 is constantly changing, the distance of 10-50 μm is the working state, that is, the working end 102, and the distance greater than 50 μm is the non-working state, that is, the non-working end 103. Wherein, the machining tracks of all working ends 102 together constitute the ultra-long stainless steel pipe breaking groove 601.

[0175] Wherein, the annular discharge end 101 of the tool electrode 1 includes a plurality of working ends 102 distributed in a ring shape, and when the discharge end moves eccentrically around the central axis of the inner cavity of the stainless steel pipe 6 for machining, the plurality of working ends 102 are in a non-synchronous and non-continuous machining state; and the machining tracks of the plurality of working ends together constitute the breaking groove of the stainless steel pipe 6.

[0176] Wherein, after one revolution of the eccentric motion of the tool electrode 1, all end faces of the discharge end 101 participate in the electric spark machining, that is, all working ends 102 constitute a complete discharge end 101, and the machining tracks of all working ends 102 together constitute the ultra-long stainless steel pipe breaking groove 601; along the machining direction 7, the working end 102 presents a "circumferential motion" phenomenon on the discharge end 101, that is, at different times, the positions of the working ends 102 are different, so that all working ends 102 alternately and orderly perform machining, and the machining direction 7 is the circumferential direction around the outer end face of the stainless steel pipe 6, and the face where the circumferential direction is located is perpendicular to the central axis of the inner cavity of the stainless steel pipe 6.

[0177] Specifically, one end of the tool electrode 1 is installed on the machine tool, the discharge end 101 of the tool electrode 1 is sleeved on the outer end face of the stainless steel pipe 6, 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 pipe 6, and there is a clearance between the discharge end 101 and the outer end face of the stainless steel pipe 6, that is, the diameter of the inner circular end of the discharge end 101 is greater than the outer diameter of the stainless steel pipe 6, for example, the diameter of the inner circular end is 10-20 mm, which is 5-10 times the outer diameter of the stainless steel pipe 6. In this way, the value of the single-sided feed amount O1O2 can be easily determined during electric spark machining. During machining, the tool electrode 1 is swung by the machine tool, 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 pipe 6.

[0178] Wherein, the single-sided feed amount O1O2 satisfies:

[0179] O1O2=S1+(H1-H2)-S2

[0180] Wherein, O1 represents the center point of the discharge end 101 of the tool electrode;

[0181] O2 represents the center point of the inner cavity of the stainless steel pipe 6;

[0182] H1 is the wall thickness of the stainless steel pipe 6;

[0183] H2 is the wall thickness of the fracture groove 601;

[0184] S2 is the machining clearance, which refers to the closest distance between the working end 102 and the end face of the stainless steel tube 601 when the tool electrode 1 moves eccentrically.

[0185] S1 indicates that there is a margin gap between the discharge end 101 and the outer end face of the stainless steel tube 6.

[0186] Wherein, S1 satisfies:

[0187]

[0188] Among them, S 11 S 12 S 13 S 14 The actual clearance value between four points selected on the discharge end 101 of the tool electrode and the outer end face of the stainless steel tube 6 is given. These four points are evenly distributed on the discharge end 101.

[0189] For example, S 11 S 12 S 13 S 14 The corresponding values ​​are 2.055mm, 2.060mm, 2.065mm, and 2.050mm, respectively. At this time, S1 = 2.058mm.

[0190] The machining gap S2 is set to 10-50 μm to meet the requirements of electrical discharge machining.

[0191] For example, S2 = 10 μm; H1 = 0.5 mm, H2 = 0.3 mm, S1 = 2.058 mm, and O1O2 = 2.248 mm.

[0192] Among them, the automatic centering module on the machine tool can be used to measure S. 11 S 12 S 13 S 14 If the four values ​​are equal, the center of the inner circle 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.

[0193] Among them, after the center of the discharge end 101 of the machine tool adjustment tool electrode 1 is aligned with the central axis of the inner cavity of the stainless steel tube 6, the actual measured S 11 S 12 S 13 S 14The closer the four values are, the more accurate the value of S1 is, and the more accurate the unilateral feed amount O1O2 is, so that the machining gap accuracy can be ensured during eccentric movement of the tool electrode 1, and the machining depth of the working end 101 is ensured, so that the size accuracy of the broken groove 601 machined is ensured.

[0194] After the center of the discharge end 101 of the tool electrode 1 is adjusted to coincide with the inner cavity axis of the stainless steel pipe 6, the tool electrode 1 is in an eccentric movement state under the action of the machine tool, and the detailed process is as follows.

[0195] The movement 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 pipe 6 are described as follows.

[0196] The tool electrode 1 is moved so that O1 is away from O2 by a distance equal to the unilateral feed amount O1O2, and at this time, the distance between O1 and O2 is O1O2.

[0197] O1 is rotated around O2 with O1O2 as the radius, and at this time, the trajectory of O1 is a circle, the center of which is O2 and the radius of which is O1O2.

[0198] During the movement of O1, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel pipe 6 reaches 10 μm, the power supply device is started to supply pulse voltage to the tool electrode 1 and the stainless steel pipe 6, and the surface metal of the stainless steel pipe 6 is etched away at a machining speed of 0.04 g / min until the distance between O1 and O2 is O1O2, and then O1 moves in a circular motion around O2.

[0199] In order to further illustrate the movement trajectory of the tool electrode 1, an arbitrary point O3 on the discharge end 101 is selected, and the trajectory of O3 is described as follows.

[0200] The tool electrode 1 is moved so that O3 moves towards O2 by a distance of O1O2.

[0201] 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.

[0202] 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 pipe 6 reaches 10 μm, the power supply device is started to supply pulse voltage to the tool electrode 1 and the stainless steel pipe 6, and the surface metal of the stainless steel pipe 6 is etched away at a machining speed of 0.04 g / min until the movement distance of O3 reaches O1O2, and then O3 moves in a circular motion around its initial position.

[0203] Therefore, in the eccentric movement of the tool electrode 1, the distance between the inner circular end face of the discharge end 101 and the outer surface of the stainless steel pipe 6 changes constantly, and the distance between each part of the inner circular end face of the discharge end 101 and the outer end face of the stainless steel pipe 6 changes from close to far, and then the discharge end 101 changes from the working state to the non-working state, that is, the dynamic change between the working end 102 and the non-working end 103 is realized, so that the working end 102 of the tool electrode 1 is prevented from being in a continuous machining state, and the wear of the working end 102 of the tool electrode 1 is greatly reduced.

[0204] The discharge end 101 and the outer end face of the stainless steel pipe 601 have a clearance S1, which is used to ensure that the non-machining gap between the non-working end 103 at the discharge end 101 and the end face of the stainless steel pipe 6 is large enough, and then the pulse voltage released at the non-working end 103 cannot etch the metal on the surface of the stainless steel pipe 6. Therefore, when the tool electrode 1 is eccentrically moved, the dynamic change between the working end 102 and the non-working end 103 can be realized.

[0205] 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 pipe 6 is electrically connected to another output end of the power supply device. The power supply device includes a pulse power supply, and the two output ends thereof are respectively connected to the positive and negative electrodes of the pulse power supply to output pulse voltage.

[0206] For example, in the machining process, the electrical parameters satisfy:

[0207] The pulse width is 30-60μs, the pulse interval is 20-30μs, the average machining current is 0.8-2A, and the average machining voltage is 30-60V.

[0208] Specifically, the driving assembly includes a transmission rod 2, one end of the transmission rod 2 is connected to the tool electrode 1 through a universal adjustable clamp, and the other end of the transmission rod 2 is installed on the 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 eccentrically move around the central axis of the inner cavity of the stainless steel pipe 6.

[0209] Specifically, the transmission rod 2 swings clockwise in the swing plane YZ, which is parallel to the plane where the discharge end 101 is located. Therefore, the discharge end of the tool electrode 1 eccentrically moves around the central axis of the inner cavity of the stainless steel pipe 6. During machining, the stainless steel pipe 6 remains stationary.

[0210] For example, in the machining process, the non-electrical parameters satisfy:

[0211] The swing speed of the driving assembly is 0.4-0.6rpm, the machining gap is 10-50μm, the machining speed is 0.02-0.045g / min, and the single-sided feed amount is 2.214-2.2.316mm.

[0212] Specifically, the universal adjustable clamp is connected with the tool electrode 1, and is used for adjusting the control position of the tool electrode 1 to realize the alignment of the tool electrode, so as to ensure the machining precision.

[0213] The universal adjustable clamp comprises 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 in the YZ plane direction of the machine tool, wherein the clamping part, the first adjusting part and the second adjusting part are sequentially connected with each other from bottom to top; during alignment, the tool electrode 1 is first aligned in the XY plane direction of the machine tool by using the first adjusting part, and then the tool electrode 1 is aligned in the YZ plane direction of the machine tool by using the second adjusting part, so as to ensure that the discharge end surface of the tool electrode 1 is perpendicular to the position to be machined of the stainless steel pipe.

[0214] Specifically, the clamping part comprises a reference seat 10 and a clamping seat 11 mounted on the reference seat 10, wherein the clamping seat 11 and the reference seat 10 are adjacent to each other and form a clamping space for mounting the tool electrode 1, and the upper end of the tool electrode 1 is mounted in the clamping space during mounting, so as to clamp the tool electrode 1.

[0215] Further, the clamping part further comprises 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 of the fastening screw 12 penetrates through the clamping seat 11 and is located in the clamping space. During mounting, after the upper end of the tool electrode 1 is placed in the clamping space, the fastening screw 12 is rotated to press the end surface of the tool electrode 1 by using the fastening screw 12, so as to press the tool electrode 1 and avoid the sliding of the tool electrode 1.

[0216] The inner end surface of the clamping space, which is connected with the tool electrode 1, is a V-shaped surface, the upper end surface of the tool electrode 1 is matched with the V-shaped surface, and the angle of the V-shaped surface is 90°, so as to prevent the tool electrode 1 from sliding in the horizontal direction during the process of pressing the tool electrode 1 by the fastening screw 12. In this way, the tool electrode 1 is clamped.

[0217] Specifically, the first adjusting part comprises a first fixed seat 13 and a second fixed seat 14 which are distributed upward and downward, the second fixed seat 14 is mounted on the lower end of the first fixed seat 13 by a vertical screw 15, and the adjacent surfaces of the first fixed seat 13 and the second fixed seat 14 are provided with a gap; wherein one end of the vertical screw 15 penetrates through the first fixed seat 13 and the second fixed seat 14, and is screwed with the first fixed seat 13 and is in sliding connection with the second fixed seat 14, and a nut is arranged at the bottom of the vertical screw 15 to limit the second fixed seat 14 in the direction perpendicular to the second fixed seat 14, so as to adjust the inclination angle of the second fixed seat 14 in the horizontal direction by rotating the vertical screw 15.

[0218] Four vertical screws 15 are arranged on the first fixing base 13 vertically and uniformly, so that the inclination angle of the second fixing base 14 in the horizontal direction can be adjusted by rotating any vertical screw 15. The top of each vertical screw 15 is a rotating head, which is convenient for rotating the vertical screw 15. In the initial state, the rotating head of each vertical screw 15 is arranged with the same clearance gap from the upper end surface of the first fixing base 13, so as to ensure that the vertical screw 15 has enough space to rotate.

[0219] For example, when the vertical screw 15 at the left end of the first fixing base 13 is rotated clockwise, the left end of the second fixing base 14 is inclined downward.

[0220] Further, the lower end of the second fixing base 14 is fixedly installed with an insulating plate 16, and the lower end surface of the reference base 10 is fixedly connected with the insulating plate 16, so that the tool electrode 1 can be aligned in the vertical direction when the inclination angle of the second fixing base 14 in the horizontal direction is adjusted, and the insulating plate 16 can prevent the operator from being electrically shocked.

[0221] For example, when the left end of the second fixing base 14 is inclined downward, the tool electrode 1 is inclined to the right.

[0222] Specifically, the second adjusting part includes a clamp head 17, a first connecting body 18, a second connecting body 19 and a rotating body 20. The clamp head 17 is installed on the machine tool, the first connecting body 18 is fixedly connected with the clamp head 17, the rotating body 20 is located between the first connecting body 18 and the second connecting body 19, the upper end of the rotating body 20 is rotatably connected with the first connecting body 18 in the horizontal direction, the lower end of the rotating body 20 is fixedly connected with the second connecting body 19, and the lower end of the second connecting body 19 is fixedly connected with the top of the first fixing base 13. In this way, the position of the first fixing base 13 in the horizontal direction can be adjusted by rotating the rotating body 20 in the horizontal direction, so as to align the tool electrode 1 in the YZ direction of the machine tool.

[0223] The lower end of the first connecting body 18 is provided with a cavity for placing the rotating body 20, the rotating body 20 is placed in the cavity, and the upper end of the rotating body 20 is rotatably installed on the top wall of the cavity; a corner adjusting screw 21 is installed at one end of the rotating body 20, one end of the corner adjusting screw 21 is screwed on the rotating body 20, and the other end of the corner adjusting screw 21 is located outside the first connecting body 18 through the cavity wall of the first connecting body 18; a slot 22 is provided on the side end face of the first connecting body 18, so that when the rotating body 20 rotates, the corner adjusting screw 21 can slide in the slot 22; the end of the corner adjusting screw 21 located outside the first connecting body 18 is a screw head, by rotating the screw head, the corner adjusting screw 21 can be adjusted to approach or move away from the direction of the first connecting body, thereby adjusting the pressing force of the corner adjusting screw 21 on the first connecting body 18, and further adjusting the state of the rotating body 20.

[0224] For example, rotate the corner adjusting screw 21 counterclockwise until the pressing force of the corner adjusting screw 21 on the first connecting body 18 is eliminated, at this time, the rotating body 20 can rotate freely, and the rotating angle is limited by the length of the slot 22.

[0225] For example, rotate the corner adjusting screw 21 clockwise until the corner adjusting screw 21 is pressed on the end face of the first connecting body 18, at this time, the rotating body 20 cannot rotate.

[0226] Further, an angle value scale surface is provided in the length direction of the slot 22, that is, a rotating angle scale surface, wherein 0° is taken as the position where the corner adjusting screw 21 is located in the middle of the slot 22, the maximum position of the corner adjusting screw 21 when rotating clockwise is 10°-30°, and the maximum position of the corner adjusting screw 21 when rotating counterclockwise is -30°--10°, so as to realize accurate adjustment of the rotating angle of the rotating body 20, and further realize accurate adjustment of the tool electrode 1.

[0227] Wherein, the surface provided with a scale on the end face of the first connecting body 18 is taken as a reference surface, the corner adjusting screw 21 is pushed to rotate, and the pushing angle is β;

[0228] Wherein, the center of the rotating body 20 is taken as the center, and the pushing angle β of the corner adjusting screw 21 satisfies:

[0229]

[0230] Wherein, S: taking the discharge end face of the tool electrode 1 as a reference surface, moving the micrometer in the Y-axis direction of the machine tool, and the moving distance of the micrometer needle is S;

[0231] v1 is the speed of the micrometer moving;

[0232] t1 is the time of the micrometer moving.

[0233] In the process of aligning the tool electrode 1, the reference surface of the tool electrode 1 is set by using a dial gauge to align the tool electrode 1, and the universal adjustable clamp is adjusted so that the relative position error of the tool electrode with the three dimensions of the machine tool XYZ axis is ≤0.01 mm.

[0234] Specifically, one end of the transmission rod 2 is fixedly connected with 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. In the process of machining, the other end of the transmission rod 2 is installed on the machine tool, so that the machine tool drives the transmission rod 2 to swing, and then the tool electrode 1 and the universal adjustable clamp are driven by the transmission rod 2 to move, so as to realize the eccentric motion of the discharge end 101 of the tool electrode 1 around the inner cavity axis of the stainless steel pipe 6.

[0235] Specifically, the bearing assembly includes an equal-height positioning block 3 and an auxiliary bearing 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.

[0236] Specifically, two equal-height positioning blocks 3 are provided, and the two equal-height positioning blocks 3 are respectively located on the two sides of the to-be-machined position of the stainless steel pipe 6, so as to ensure the stability of the to-be-machined position of the stainless steel pipe 6 in the process of machining. For example, the distance between the two equal-height positioning blocks 3 is 20-50 mm.

[0237] Specifically, two auxiliary bearing blocks 4 are provided, and the two equal-height positioning blocks 3 are located between the two auxiliary bearing blocks 4, so that the two ends of the stainless steel pipe 6 are supported and positioned by the two auxiliary bearing blocks 4, further ensuring the stability of the stainless steel pipe 6 in the process of machining.

[0238] Specifically, the upper end faces of the equal-height positioning block 3 and the auxiliary bearing block 4 are flush, and the upper end faces 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 grooves to limit the stainless steel pipe 6.

[0239] Further, the equal-height positioning block 3 is further provided with a clamping plate 5, the clamping plate 5 covers the V-shaped groove and is clamped on the equal-height positioning block 3, so as to limit the stainless steel pipe 6 and further improve the stability of the stainless steel pipe 6. For example, the angle of the V-shaped groove is 60°-90°, and the depth is 5-10 mm.

[0240] Before placing the stainless steel pipe 6 on the equal-height positioning block 3, the tool electrode 1 needs to be aligned by using the machine tool first, then the stainless steel pipe 6 is inserted into the discharge end 101 of the tool electrode 1, and finally the stainless steel pipe 6 is clamped by using the equal-height positioning block 3, the auxiliary bearing block 4 and the clamping plate 5, and the stainless steel pipe 6 is aligned by using the equal-height positioning block 3 and the auxiliary bearing block 4.

[0241] Specifically, after the tool electrode 1 is aligned, the positions of the equal-height positioning block 3 and the auxiliary bearing block 4 on the machine tool are adjusted by the machine tool XYZ axis, so as to align the stainless steel pipe 6, to ensure that the axis in the inner cavity of the stainless steel pipe 6 coincides with the center line of the discharge end 101 of the tool electrode 1, so as to determine the value of the single-sided feeding amount, and further to improve the machining precision.

[0242] Wherein, the alignment process of the stainless steel pipe 6 is as follows.

[0243] Firstly, firstly, the two equal-height positioning blocks 3 and the two auxiliary support blocks 4 are fixed on the workbench 9 of the machine tool, and then the side surface is aligned with the machine tool X axis by using the dial indicator, and the parallelism error is ≤0.01mm.

[0244] Before the stainless steel pipe 6 is placed on the equal-height positioning block 3, the stainless steel pipe 6 is first inserted into the discharge end 101 of the tool electrode 1, and then the stainless steel pipe 6 is placed on the equal-height positioning block 3 and the auxiliary bearing block 4, so that the stainless steel pipe 6 is aligned by the equal-height positioning block 3 and the auxiliary bearing block 4.

[0245] Compared with the prior art, the first adjusting part of the universal adjustable clamp is used to adjust the inclination angle of the tool electrode 1 in the horizontal plane, 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 dial indicator and the time and speed of the dial indicator movement, and the corresponding scale is pushed to the corresponding scale by the angle adjusting bolt 21, so as to realize high-precision adjustment of the inclination angle of the tool electrode 1 on the YZ plane of the machine tool, so as to realize the alignment of the tool electrode 1, and the operation is convenient, and the machining efficiency and precision are improved.

[0246] During machining, the super-thin long stainless steel pipe 6 is only placed in the V-shaped groove on the equal-height positioning block 3 and the auxiliary bearing block 4, and the upper surface of the super-thin long stainless steel pipe is limited by the clamping plate 5, so as to realize the clamping and positioning of the super-thin long stainless steel pipe, which is convenient and can ensure the stability of the super-thin long stainless steel pipe 6 during machining.

[0247] The discharge end 101 of the tool electrode 1 of the present application is in the shape of a circular ring, which is eccentrically moved on the outer end surface of the super-long stainless steel pipe 6, and in this process, the distance between the end surface of the discharge end 101 and the end surface of the super-long stainless steel pipe 6 to be machined is constantly changing, the distance is closer to the working end 102, and the distance is farther to the non-working end 103, so that the outer end surface of the super-long stainless steel pipe 6 is electric spark machined by the working end 102; that is, along the machining direction, the position of the working end 102 constantly changes on the inner circular end surface of the discharge end 101, that is, when the inner circular end surface of the discharge end 101 is close to the outer end surface of the super-long stainless steel pipe 6, the end surface of the discharge end 101 is the working end 102, and when the end surface is far away from the outer end surface of the super-long stainless steel pipe 6, the end surface changes to the non-working end 103, so that the dynamic change between the working end 102 and the non-working end 103 is realized, so that the working end 102 of the tool electrode 1 is avoided to be in the continuous machining state, the wear of the working end 102 of the tool electrode 1 is greatly reduced, the tool electrode wear is less than or equal to 1%, and the deformation of the working end surface of the tool electrode 1 is reduced, so that the machining precision of the breakage groove 601 of the super-long stainless steel pipe is improved.

[0248] The discharge end 101 of the tool electrode 1 of the present application is eccentrically moved on the super-long stainless steel pipe 6, and during machining, the distance between the discharge end 101 and the super-long stainless steel pipe 6 changes from large to small, and then from small to large, and in the process of changing from large to small, metal scraps are generated between the discharge end 101 and the stainless steel pipe 6, at this time, part of the metal scraps are discharged through the machining gap along with the working liquid, and in the process of changing from small to large, the distance between the discharge end 101 and the stainless steel pipe 6 can be increased by nearly 200 times, which significantly improves the efficiency of discharging metal scraps, so that the metal scraps are avoided to be accumulated at the discharge end 101 due to the discharging not in time, thereby reducing the wear of the tool electrode 1, and avoiding the risk of short circuit caused by the direct connection of the tool electrode 1 with the stainless steel pipe 6 through the metal scraps.

[0249] By eccentrically moving the discharge end 101 of the tool electrode 1 on the super-long stainless steel pipe 6, the metal scraps can be efficiently discharged, and electric spark machining with a smaller machining gap is realized, so that the machining current and the machining voltage value can be reduced, the machining cost is reduced, and the breakage groove 601 with a lower surface roughness can be obtained.

[0250] By adjusting the value of the single-sided feeding amount, the breakage groove 601 with different wall thicknesses can be machined, and by adjusting the shape of the discharge end 101 of the tool electrode 1, the breakage groove 601 with different inclined angles α can be machined, which lays a foundation for rapid production and batch production of products.

[0251] The discharge end 101 of the tool electrode 1 of the application moves eccentrically around the central axis of the inner cavity of the super-long stainless steel pipe 6 for one round, so that the machining of the breaking groove 601 of the super-long stainless steel pipe is completed, the machining is in place at one time, and the machining efficiency is significantly improved.

[0252] The application discards the traditional turning machining mode of the super-long stainless steel pipe, and uses the working end 102 of the tool electrode 1 to discharge and remove the metal on the surface of the super-long stainless steel pipe 6 to machine the breaking groove 601, that is, the tool electrode 1 does not contact the surface of the super-long stainless steel pipe during the machining process, and the deformation of the super-long stainless steel pipe is avoided, so that the damage of the super-long stainless steel pipe caused by the cutting force is overcome.

[0253] The application uses the eccentric movement of the discharge end 101 of the tool electrode 1 around the central axis of the inner cavity of the super-long stainless steel pipe to machine the breaking groove 601 of the super-long stainless steel pipe, that is, the super-long stainless steel pipe does not need to move during the machining process, so that the annular breaking groove 601 can be machined on the outer surface of the super-long stainless steel pipe, and the problem of poor coaxiality of the super-long stainless steel pipe during rotation affecting the machining precision is overcome.

[0254] 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 pipe 6, the single-sided feed amount of the end face of each part of the discharge end 101 is the same, the consistency of the machining depth of the breaking groove 601 is ensured, and the machining precision of the breaking groove 601 is improved.

[0255] Embodiment 1

[0256] A machining method of a breaking groove of a super-long stainless steel pipe, comprising the following steps:

[0257] Step 1: using a universal adjustable clamp to align the tool electrode;

[0258] Specifically, the spatial position of the universal adjustable clamp 5 is adjusted to further adjust the spatial position of the tool electrode 1.

[0259] Specifically, the tool electrode 1 is fixed on the universal adjustable clamp 5, a dial gauge is used to align the tool electrode 1 to set a reference surface, the universal adjustable clamp is adjusted, and the relative position error of the tool electrode 1 with the three dimensions of the machine tool XYZ axis is less than or equal to 0.01 mm.

[0260] Specifically, the reference surface in the XYZ three-dimensional direction is selected on the tool electrode 1, the dial head of the dial gauge is respectively touched on the reference surface, and then the dial gauge is moved. If the dial needle on the dial plate shows that the movement is 0-10 μm, the accuracy meets the requirements, the alignment process is ended, if the dial needle on the dial plate shows that the movement is greater than 10 μm, the accuracy does not meet the requirements, the three-dimensional position of the tool electrode on the machine tool is adjusted by using the corresponding adjustment of the universal adjustable clamp, until the dial needle on the dial plate shows that the movement is 0-10 μm, so that the alignment of the tool electrode 1 is realized.

[0261] Wherein, the tool electrode is aligned in three dimensions of the machine tool XYZ by using the micrometer, and after the alignment, the value of the needle of the micrometer moving in the three dimensions of XYZ is the alignment error, that is, the relative position error.

[0262] Wherein, in the three directions of the machine tool XYZ, a small plane on the tool electrode 1 can be machined as a reference surface.

[0263] For example, in the Z-axis direction of the machine tool, the tool electrode 1 is aligned by using the micrometer; wherein, the discharge end surface 101 of the tool electrode 1 is used as the reference surface, the head of the micrometer touches the upper end horizontal surface of the transmission rod 2, and the micrometer is moved up and down; if the needle of the micrometer moves 0-10 μm, the position of the tool electrode 1 in the Z-axis direction is in line with the requirements; if the needle of the micrometer moves more than 10 μm, the position of the tool electrode 1 is adjusted by the first adjusting part of the universal adjustable clamp, and after the adjustment, the micrometer is used to continue to detect until the micrometer moves within 0-10 μm.

[0264] Wherein, the adjustment process of the universal adjustable clamp is as follows:

[0265] Specifically, the tool electrode 1 is first installed into the clamping part, and the tool electrode is pressed by using the fastening screw 12;

[0266] Then, the discharge end surface of the tool electrode 1 is used as the reference surface, the head of the micrometer touches the reference surface, and moves in the Z-axis direction of the machine tool; if the needle of the micrometer moves 0-10 μm, the position of the tool electrode in the front and back directions of the XY plane of the machine tool does not need to be adjusted; if the needle of the micrometer moves more than 10 μm, the position of the tool electrode 1 needs to be adjusted by the first adjusting part.

[0267] Wherein, during the upward movement of the micrometer, if the needle moves clockwise, the upper end of the tool electrode 1 inclines towards the reference surface; if the needle moves counterclockwise, the upper end of the tool electrode 1 inclines towards the opposite direction of the reference surface; at this time, the up and down space positions of the vertical screws 15 close to the two sides of the discharge end surface are adjusted, so that the tool electrode 1 is aligned in the front and back directions of the XY plane of the machine tool.

[0268] Wherein, the vertical screw 15 at the high end is rotated clockwise, and the vertical screw 15 at the low position is rotated counterclockwise, so as to align the tool electrode 1 in the front and back directions of the XY plane of the machine tool.

[0269] Then, taking the upper end surface of the second fixed seat 14 as a reference surface, the dial head of the dial gauge touches the reference surface, and moves in the Y-axis direction of the machine tool. If the dial needle of the dial gauge moves 0-10 μm, the position of the tool electrode 1 does not need to be adjusted in the left-right direction of the XY plane of the machine tool. If the dial needle of the dial gauge moves more than 10 μm, the position of the tool electrode 1 needs to be adjusted by the first adjusting part;

[0270] The upper end surface of the tool electrode 1 is a plane, which is parallel to the center line of the discharge end 101, and which is connected with the lower end surface of the insulating plate 16. The upper end surface of the second fixed seat 14 is parallel to the upper end surface of the tool electrode 1. Thus, taking the upper end surface of the second fixed seat 14 as a reference surface can realize the alignment of the tool electrode 1 in the left-right direction of the XY plane of the machine tool.

[0271] If the dial needle moves clockwise during the right movement of the dial gauge, the right end of the second fixed seat 14 is high. At this time, the vertical screw 15 close to the right end of the second fixed seat 14 is adjusted to rotate clockwise, or the vertical screw 15 close to the left end of the second fixed seat 14 is adjusted to rotate counterclockwise.

[0272] If the dial needle moves counterclockwise during the right movement of the dial gauge, the left end of the second fixed seat 14 is high. At this time, the vertical screw 15 close to the left end of the second fixed seat 14 is adjusted to rotate clockwise, or the vertical screw 15 close to the right end of the second fixed seat 14 is adjusted to rotate counterclockwise. Thus, the tool electrode can be aligned in the left-right direction of the XY plane of the machine tool.

[0273] Then, taking the discharge end surface of the tool electrode 1 as a reference surface, the dial head of the dial gauge touches the reference surface, and moves in the Y-axis direction of the machine tool. If the dial needle of the dial gauge moves 0-10 μm, the position of the tool electrode 1 does not need to be adjusted in the YZ plane direction of the machine tool. If the dial needle of the dial gauge moves more than 10 μm, the position of the tool electrode needs to be adjusted by the second adjusting part;

[0274] If the dial needle moves clockwise during the right movement of the dial gauge, the tool electrode 1 is inclined in the clockwise direction. At this time, the corner adjusting screw 21 is rotated counterclockwise. If the dial needle moves counterclockwise, the tool electrode 1 is inclined in the counterclockwise direction. At this time, the corner adjusting screw 21 is rotated clockwise.

[0275] Wherein, the machine tool control micrometer is used to move in the XYZ three-dimensional direction, and the micrometer moving time and speed are recorded to obtain the inclination angle of the tool electrode in the XYZ three-dimensional direction. Wherein, in the YZ plane direction of the machine tool, the tool electrode 1 is aligned by using the micrometer, the micrometer moving time is recorded as t1, the speed is recorded as v1, and the micrometer needle clockwise rotation distance is recorded as S; if 0μm<S<10μm, at this time, the angle adjusting screw 21 does not need to be adjusted; if S>10μm, at this time, the angle adjusting screw 21 needs to be adjusted counterclockwise, and the center of the rotating body 20 is taken as the center, and the pushing angle β of the angle adjusting screw 21 satisfies:

[0276]

[0277] Wherein, when the angle adjusting screw 21 needs to be pushed counterclockwise, the angle adjusting screw 21 is first rotated counterclockwise, so that the angle adjusting screw 21 is in active connection with the first connecting body 18, and then the angle adjusting screw 21 is pushed counterclockwise, and the pushing angle is-β. In this process, the scale at the notch 22 of the first connecting body 18 is adjusted to realize the alignment of the tool electrode 1 in the YZ plane direction of the machine tool. After the alignment is completed, the angle adjusting screw 21 is rotated clockwise to press on the end face of the first connecting body 18, so as to avoid the sliding of the angle adjusting screw 21.

[0278] In this way, the alignment process of the tool electrode 1 is realized.

[0279] Step 2: clamp the stainless steel pipe 6 by using the bearing assembly, and align the stainless steel pipe 6;

[0280] Specifically, first, fix two pieces of equal-height positioning blocks 3 and two pieces of auxiliary supporting blocks 4 on the workbench 9, use the micrometer to pull the table to align the side surface parallel to the machine tool X axis, and use the machine tool to adjust the position of the equal-height positioning block 3 and the auxiliary supporting block 4, wherein the parallelism error is ≤0.01mm.

[0281] Then place the stainless steel pipe 6 on the equal-height positioning block 3, and before placing, first pass the stainless steel pipe 6 through the inner circle end of 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 block 3, and the distance between the two equal-height positioning blocks 3 is 30mm;

[0282] Then place the two ends of the stainless steel pipe 6 on the auxiliary supporting block 4, and finally fix it with the clamping plate 5.

[0283] 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 axis of the stainless steel pipe 6;

[0284] Specifically, first, the machine tool moves the bearing assembly in the X-axis direction to adjust the position of the stainless steel tube 6, so that the to-be-processed position of the stainless steel tube 6 is located in the discharge end 101 of the tool electrode 1;

[0285] Then, the machine tool automatically measures the values of S 11 , S 12 , S 13 , and S 14 by the centering module. If the four values are equal or the error is within ±0.02 mm, 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 not, the machine tool continues to adjust the position of the bearing assembly until the requirement is met.

[0286] Step 4: Using kerosene and water as working fluid, the tool electrode 1 is used to perform electric spark machining on the stainless steel tube 6.

[0287] S101: Control 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;

[0288] Specifically, the machine tool drives the transmission rod 2 to swing in the YZ plane, and then controls 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 through the transmission rod 2. The eccentric movement direction 8 is as shown in Figure 10 .

[0289] The swing speed of the transmission rod 2 is 0.5 rpm.

[0290] S 11 , S 12 , S 13 , and S 14 The actual measured values are 2.055 mm, 2.060 mm, 2.065 mm, and 2.050 mm, respectively. At this time, S1=2.058 mm.

[0291] The machining gap S2 is 10 μm.

[0292] The single-sided feed amount O1O2=S1+(H1-H2)-S2=2.058+(0.5-0.3)-0.01=2.248 mm.

[0293] The machining speed is 0.04 g / min.

[0294] S102: When the tool electrode 1 performs eccentric movement, power is supplied to the tool electrode 1 to perform electric spark machining.

[0295] Specifically, the electrical parameters satisfy:

[0296] The pulse width is 40 μs, the pulse interval is 26 μs, the average machining current is 1 A, and the average machining voltage is 40 V.

[0297] In this way, the discharge end of the tool electrode moves eccentrically around the inner cavity axis of the stainless steel pipe for one cycle, and the machining of the breaking groove of the stainless steel pipe is completed, the machining is in place at one time, and the machining efficiency is significantly improved.

[0298] The above machining method is used to machine the breaking grooves of 01-10 pieces of ultra-long stainless steel pipes, and the machining parameters are shown in Table 1.

[0299] Table 1 Machining parameters

[0300]

[0301] The machining requirements are that the wall thickness of the breaking groove is 0.3±0.05mm, and the bevel angle α is 90°.

[0302] The detection results are shown in Table 2.

[0303] Table 2 Detection results

[0304]

[0305]

[0306] Among them, the electrode consumption ratio is E / W*100%, wherein E is the diameter size variation of the discharge end of the tool electrode, and W is the initial diameter size of the inner circle end of the tool electrode.

[0307] As can be seen from Table 2, the average value of the breaking groove depth of the 10 pieces of stainless steel pipes machined by the present application is 0.2146mm, the standard deviation is 0.01427, the dispersion coefficient is 0.07, the breaking groove angle is 90°, the average value of the breaking groove wall thickness is 0.299mm, the standard deviation is 0.006681, and the dispersion coefficient is 0.02. It can be seen that the machining method of the present application can realize the machining of the breaking groove of the ultra-long stainless steel pipe, and the machined breaking groove has high precision and stability, and the ultra-long stainless steel pipe is not damaged, and the tool electrode is less consumed.

[0308] Those skilled in the art can understand that all or part of the processes of the above-mentioned embodiments can be completed by a computer program instructing related hardware, and the program can be stored in a computer readable storage medium. The computer readable storage medium is a disk, an optical disk, a read-only memory or a random access memory, etc.

[0309] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical range disclosed by the present application can be easily thought of by those skilled in the art, which should be covered within the protection scope of the present application.

Claims

1. A method of machining a V-groove in an ultra-long thin-walled tube, characterized by, The method comprises the following steps: Step 1: aligning the tool electrode by using a universal adjustable clamp; Step 2: clamping the thin-walled pipe by using a bearing assembly and aligning the thin-walled pipe; Step 3: machining the V-shaped groove on the surface to be machined by using the working state of the plurality of electric spark machining points of the tool electrode arranged circumferentially around the thin-walled pipe; The same electric spark machining point is in the working state or the non-working state by changing the distance between the electric spark machining point and the surface to be machined; One end of the tool electrode is a discharge end, and the discharge end comprises a plurality of electric spark machining points arranged circumferentially around the thin-walled pipe; during machining, the plurality of electric spark machining points arranged circumferentially around the ultra-slim thin-walled pipe form a continuous circular ring, and the inner circle end of the circular ring matches the shape of the V-shaped groove; The discharge end of the tool electrode is sleeved on the ultra-slim thin-walled pipe, and during machining, the discharge end of the tool electrode is driven by the driving assembly to make eccentric motion around the central axis of the inner cavity of the thin-walled pipe, and the ultra-slim thin-walled pipe remains stationary; The machining direction is the circumferential direction of the outer end surface of the ultra-slim thin-walled pipe, and the center line of the circumferential direction coincides with the central axis of the inner cavity of the ultra-slim thin-walled pipe; The step 1 comprises: S11: clamping the tool electrode by using the clamping part of the universal adjustable clamp, and pressing the tool electrode by using the fastening screw; S12: adjusting the up and down space positions of the vertical screws in the XY plane direction of the machine tool to adjust the inclination angle of the second fixed seat in the horizontal direction; S13: adjusting the position of the rotating body in the horizontal plane in the YZ plane direction of the machine tool to adjust the inclination angle of the tool electrode in the YZ plane of the machine tool.

2. The method of claim 1, wherein: The universal adjustable clamp comprises a clamping part for clamping the tool electrode, a first adjusting part for aligning the tool electrode in the XY plane of the machine tool, and a second adjusting part for aligning the tool electrode in the YZ plane of the machine tool; The clamping part comprises a reference seat, a clamping seat mounted on the reference seat, and a fastening screw for adjusting the clamping force of the tool electrode; The first adjusting part comprises first and second fixed seats distributed upward and downward, the second fixed seat is mounted on the lower end of the first fixed seat by a plurality of vertical screws, and the clamping part is mounted on the lower end of the second fixed seat; The second adjusting part comprises a clamp head mounted on the machine tool, a first connecting body fixedly connected with the clamp head, a rotating body rotationally connected with the first connecting body in the horizontal direction, and a second connecting body fixedly connected with the rotating body; the second connecting body is connected with the first fixed seat; One end of the rotating body is provided with a rotation angle adjusting screw, one end of the rotation angle adjusting screw is screwed on the rotating body, and an angle value scale surface is arranged on the end surface of the first connecting body.

3. The method of claim 1, wherein, Step S13 comprises: S131: taking the discharge end surface of the tool electrode as a reference surface, moving the reference surface along the Y-axis direction of the machine tool by using a dial gauge in the YZ plane direction of the machine tool to align the tool electrode; S132: pushing the rotation angle adjusting screw to adjust the inclination angle of the tool electrode in the YZ plane of the machine tool by driving the rotating body to rotate through the rotation angle adjusting screw.

4. The method of claim 3, wherein: In step S132, the surface provided with the scale on the end surface of the first connecting body is taken as a reference surface, the rotation angle adjusting screw is pushed, and the pushing angle is β. Wherein, with the center of the rotating body as the center, the angle β pushed by the angle adjusting bolt satisfies: Wherein, S is the moving distance of the dial of the dial gauge when detecting the inclination angle of the tool electrode in the YZ plane of the machine tool; v1 is the moving speed of the dial gauge; t1 is the moving time of the dial gauge.

5. The method of claim 1, wherein: The center line of the discharge end of the tool electrode is parallel to the upper and lower end faces of the second fixing base, and the tool electrode moves synchronously when the second fixing base is adjusted.

6. The method of claim 1, wherein: When the discharge end of the tool electrode performs machining by eccentric motion around the central axis of the thin-walled pipe inner cavity, the single-side feed amount O1O2 satisfies: O1O2=S1+(H1-H2)-S2 Wherein, H1 is the wall thickness of the thin-walled pipe; H2 is the wall thickness of the V-shaped groove; S1 is the distance between the discharge end of the tool electrode and the surface to be machined before machining; and S2 is the machining gap.

7. The method of claim 1, wherein: The non-electric parameters satisfy: The swing speed of the driving assembly is 0.4-0.6 rpm, the machining gap is 10-50 μm, and the machining speed is 0.02-0.045 g / min; Wherein, the electric parameters satisfy: The pulse width is 30-60 μs, the pulse interval is 20-30 μs, the average machining current is 0.8-2 A, and the average machining voltage is 30-60 V.

8. The method of claim 5, wherein, The step 2 comprises: S21: fixing the bearing assembly on the worktable of the machine tool and aligning it by using the machine tool; S22: passing the thin-walled pipe through the discharge end of the tool electrode and clamping the thin-walled pipe by using the bearing assembly; S23: adjusting the bearing assembly by using the machine tool to drive the thin-walled pipe to move until the central axis of the thin-walled pipe inner cavity coincides with the center line of the discharge end of the tool electrode.

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