A processing device and method for an ultra-fine long stainless steel pipe breaking groove

Abstract

The application relates to a processing device and method for a folding groove of an ultra-long stainless steel pipe, and belongs to the technical field of ultra-long pipe processing, which solves the problem that high-precision processing of a folding groove on an ultra-long stainless steel pipe is difficult to realize in the prior art. The processing device comprises a tool electrode installed on a machine tool, a bearing assembly for clamping the stainless steel pipe, and a driving assembly for controlling the moving state of the tool electrode; one end of the tool electrode is a discharge end, the discharge end comprises a plurality of electric spark machining point positions arranged around the stainless steel pipe in the circumferential direction, and the same electric spark machining point position comprises a working state and a non-working state; the working state of the plurality of electric spark machining point positions arranged around the stainless steel pipe in the circumferential direction realizes the processing of the folding groove on the surface to be processed. High-precision processing of the folding groove of the ultra-long stainless steel pipe is realized, the folding groove can be processed in place at one time, and the processing efficiency is significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-long pipe machining, and particularly relates to an ultra-long stainless steel pipe breakage groove machining device and method. BACKGROUND

[0002] Breakage grooves need to be machined on some ultra-long flight products, which are used to separate the flight product guiding system from the product fairing body when the product reaches a predetermined height and position; since the ultra-long flight product has the characteristics of small diameter and thin wall thickness, the size of the breakage groove machined thereon is smaller. For the flight product whose size control is crucial, the machining precision requirement of the breakage groove puts forward higher requirements on the machining method.

[0003] It is difficult to meet the machining precision requirement of the breakage 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 breakage groove.

[0004] Therefore, in order to meet the machining requirement of the breakage groove on the ultra-long flight product, a new breakage groove machining device and method need to be explored. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide an ultra-long stainless steel pipe breakage groove machining device and method, so as to solve the problem that it is difficult to realize high-precision machining of the breakage groove on the ultra-long stainless steel pipe.

[0006] In one aspect, the embodiments of the present application provide an ultra-long stainless steel pipe breakage groove machining device, which comprises a tool electrode installed on a machine tool, a bearing assembly for clamping the stainless steel pipe, and a driving assembly for controlling the movement state of the tool electrode.

[0007] The 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 stainless steel pipe. The same electric spark machining point comprises a working state and a non-working state.

[0008] The working state of the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe realizes the machining of the breakage groove on the surface to be machined.

[0009] Based on the further improvement of the above device, the bearing assembly comprises an equal-height positioning block, an auxiliary positioning block and a clamping plate installed on the machine tool.

[0010] The equal-height positioning block and the auxiliary positioning block are used for clamping the stainless steel pipe.

[0011] The clamping plate is clamped on the equal-height positioning block, so as to limit the stainless steel pipe.

[0012] The positions of the equal-height positioning blocks and the auxiliary positioning blocks on the machine tool are adjustable.

[0013] Based on the further improvement of the above device, the bearing assembly comprises two equal-height positioning blocks and two auxiliary bearing blocks.

[0014] The two equal-height positioning blocks are respectively located on the two sides of the position to be machined of the stainless steel pipe and between the two auxiliary bearing blocks.

[0015] The distance between the two equal-height positioning blocks is 20-50mm.

[0016] Based on the further improvement of the above device, the upper end faces of the equal-height positioning blocks and the auxiliary bearing blocks are flush, and the upper end faces of the equal-height positioning blocks and the auxiliary bearing blocks are provided with V-shaped grooves for placing the stainless steel pipe to limit the stainless steel pipe.

[0017] Based on the further improvement of the above device, 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.

[0018] 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.

[0019] The threshold value is the discharge distance between the electric spark machining point and the surface to be machined that meets the machining requirements.

[0020] Based on the further improvement of the above device, the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe are continuously and uninterruptedly distributed circumferentially around the stainless steel pipe.

[0021] Based on the further improvement of the above device, the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe form a continuous circular ring, and the inner circle end of the circular ring matches the shape of the breaking groove.

[0022] Based on the further improvement of the above device, the circular ring-shaped discharge end of the tool electrode is a rigid structure and is sleeved on the stainless steel pipe, and during machining, the circular ring-shaped discharge end of the tool electrode makes eccentric motion around the central axis of the inner cavity of the stainless steel pipe.

[0023] Based on the further improvement of the above device, the driving assembly comprises a transmission rod connected to the tool electrode at one end, and during machining, the other end of the transmission rod is installed on the machine tool to drive the transmission rod to swing through the machine tool, thereby driving the discharge end of the tool electrode to make eccentric motion around the central axis of the inner cavity of the stainless steel pipe.

[0024] In one aspect, the embodiments of the present application also provide a machining method for a breaking groove of an ultra-long stainless steel pipe, which comprises machining the breaking groove of the stainless steel pipe by using the machining device.

[0025] Wherein, during processing, the non-electric parameter satisfies:

[0026] The swing speed of the driving assembly is 0.4-0.6 rpm, the processing gap is 10-50 mu m, and the processing speed is 0.02-0.045 g / min;

[0027] Wherein, during processing, the electric parameter satisfies:

[0028] The pulse width is 30-60 mu s, the pulse interval is 20-30 mu s, the average processing current is 0.8-2 A, and the average processing voltage is 30-60 V.

[0029] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0030] 1、The present application only needs to place the ultra-fine long stainless steel pipe in the V-shaped groove on the equal-height positioning block and the auxiliary bearing block during processing, and uses the clamping plate to limit the upper surface of the ultra-fine long stainless steel pipe, so as to realize the clamping and positioning of the ultra-fine long stainless steel pipe, which is convenient and can ensure the stability of the ultra-fine long stainless steel pipe during processing

[0031] 2、The discharge end of the tool electrode of the present application is circular ring-shaped, which is eccentrically moved on the outer end surface of the ultra-fine long stainless steel pipe, and in this process, the distance between the end surface of the discharge end and the end surface to be processed of the ultra-fine long stainless steel pipe is constantly changing, the distance is closer to the working end, and the distance is farther to the non-working end, so that the outer end surface of the ultra-fine long stainless steel pipe is processed by the working end; that is, along the processing direction, the position of the working end on the inner circular end surface of the discharge end is constantly changing, that is, when the inner circular end surface of the discharge end is close to the outer end surface of the ultra-fine long stainless steel pipe, the end surface of the discharge end is the working end, and when the end surface is away from the outer end surface of the ultra-fine long stainless steel pipe, the end surface changes to the non-working end, realizing the dynamic change between the working end and the non-working end, so as to avoid the working end of the tool electrode in the continuous processing state, greatly reducing the wear of the working end of the tool electrode, realizing the tool electrode wear≤1%, and further reducing the working end surface deformation of the tool electrode, so as to improve the processing precision of the ultra-fine long stainless steel pipe breaking groove.

[0032] 3、The discharge end sleeve of the tool electrode of the present application makes eccentric motion on the ultra-fine long stainless steel pipe, and during machining, the distance between the discharge end and the ultra-fine long stainless steel pipe changes from large to small and then from small to large. During the change from large to small, metal scraps are generated between the discharge end and the stainless steel pipe. At this time, part of the metal scraps are discharged through the machining gap along with the working liquid. During the change from small to large, the distance between the discharge end and the stainless steel pipe can be increased by nearly 200 times, which significantly improves the efficiency of discharging the metal scraps, thereby avoiding the accumulation of the metal scraps at the discharge end due to the failure of timely discharging the metal scraps, reducing the wear of the tool electrode, and avoiding the risk of short circuit caused by the direct connection of the tool electrode with the stainless steel pipe through the metal scraps.

[0033] 4、The eccentric motion of the discharge end sleeve of the tool electrode on the ultra-fine long stainless steel pipe can efficiently discharge the metal scraps, thereby realizing electrical discharge machining with a small machining gap. In this way, the machining current and voltage value can be reduced, the machining cost is reduced, and a fracture groove with low surface roughness can be obtained.

[0034] 5、The present application discards the traditional turning machining method for the ultra-fine long stainless steel pipe and uses the working end of the tool electrode to discharge and remove the metal on the surface of the ultra-fine long stainless steel pipe to machine the fracture groove. During machining, the tool electrode does not contact the surface of the ultra-fine long stainless steel pipe, which avoids the deformation of the ultra-fine long stainless steel pipe and overcomes the problem of damage to the ultra-fine long stainless steel pipe caused by cutting force.

[0035] 6、The present application uses the eccentric motion of the discharge end of the tool electrode around the central axis of the inner cavity of the ultra-fine long stainless steel pipe to machine the fracture groove of the ultra-fine long stainless steel pipe. During machining, the ultra-fine long stainless steel pipe does not need to rotate, and the annular fracture groove can be machined on the outer surface of the ultra-fine long stainless steel pipe. This overcomes the problem of poor coaxiality during the rotation of the ultra-fine long stainless steel pipe, which affects the machining precision.

[0036] 7、The eccentric motion of the tool electrode around the central axis of the inner cavity of the ultra-fine long stainless steel pipe for one revolution can complete the machining of the fracture groove of the ultra-fine long stainless steel pipe, realize one-time machining, and significantly improve the machining efficiency.

[0037] 8、The eccentric motion of the tool electrode around the central axis of the inner cavity of the ultra-fine long stainless steel pipe ensures that the single-sided feed of the end surface of each part of the discharge end is the same, which ensures the consistency of the machining depth of the fracture groove and improves the machining precision of the fracture groove.

[0038] 9、The discharge end of the tool electrode has the same shape as the fracture groove, i.e., the discharge end is convex and the fracture groove is concave. The cross-sectional size of the convex shape is the same as the cross-sectional shape of the concave shape. After one revolution of the eccentric motion of the tool electrode around the central axis of the inner cavity of the ultra-fine long stainless steel pipe, the depth and angle of the machined fracture groove are the required fracture groove depth and angle, which significantly improves the machining precision.

[0039] 10、By adjusting the value of the single-sided feed amount, the broken groove of different wall thickness can be processed, and by adjusting the shape of the discharge end of the tool electrode, the size of different inclined angles alpha can be processed, which lays a foundation for rapid production and batch production of products.

[0040] The above technical solutions in the present application can also be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purposes and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0041] The accompanying drawings are included to provide a further understanding of the embodiments and no limitation on the present application is intended to be represented thereby, it being intended that the present application be illustrated by way of example only and not limitation thereof, wherein like reference numerals refer to like parts throughout the various drawings.

[0042] Figure 1 The schematic diagram of the bearing assembly of the present application cooperating with the stainless steel pipe structure;

[0043] Figure 2 The schematic diagram of the tool electrode structure of the present application;

[0044] Figure 3 The schematic diagram of the tool electrode structure of the present application; Figure 2 The schematic diagram of the cross section at A-A in the present application;

[0045] Figure 4 The schematic diagram of the cross section at B-B in the present application; Figure 2 The schematic diagram of the cross section at B-B in the present application;

[0046] Figure 5 The schematic diagram of the structure of the tool electrode of the present application when the center line of the discharge end coincides with the central axis of the inner cavity of the stainless steel pipe;

[0047] Figure 6 The schematic diagram of the structure of the tool electrode of the present application when the center line deviates from the central axis of the inner cavity of the stainless steel pipe;

[0048] Figure 7 The schematic diagram of the cross section when the discharge end of the tool electrode of the present application is sleeved on the stainless steel pipe;

[0049] Figure 8 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;

[0050] Figure 9 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;

[0051] Figure 10 Fig. 1 is a structural schematic diagram of the stainless steel pipe breaking groove in the present application;

[0052] Figure 11 Fig. 2 is a structural schematic diagram of the equal-height positioning block, clamping plate and stainless steel pipe cooperation in the present application;

[0053] Figure 12 Fig. 3 is a structural schematic diagram of the auxiliary bearing block and stainless steel pipe cooperation in the present application;

[0054] Figure 13 Fig. 4 is a practical schematic diagram of the stainless steel pipe breaking groove after processing in the present application.

[0055] Reference signs:

[0056] 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; H1 - wall thickness of the stainless steel pipe; H2 - wall thickness of the breaking groove; a - breaking groove 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 surface 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

[0057] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which form a part of this application. The drawings and the associated descriptions are provided to illustrate the preferred embodiments of the present application and to explain the principles of the present application, but are not intended to limit the scope of the present application.

[0058] Generally, the ratio of diameter to length reaches 1:100-150, which belongs to super-thin long shaft. For example, the outer diameter of the 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 the outer diameter to the length of the stainless steel pipe is 1:500-600, which belongs to super-thin long stainless steel pipe. During processing, a breaking groove is generally needed to be processed on the super-thin long steel pipe. The breaking groove is used to separate the product fairing body from the product guidance system when the product reaches the predetermined height and position.

[0059] Due to the small diameter and thin wall thickness of the ultra-fine stainless steel pipe, and the wall thickness of the breaking groove position is thinner, such as the wall thickness of the breaking groove position is 0.3±0.05mm, the important dimension cannot be obtained by direct measurement; when the V-shaped breaking groove is processed at a certain position of the ultra-fine long stainless steel pipe, it is difficult to ensure the wall thickness dimension of the breaking groove position by using the traditional turning processing method, because the centrifugal force of the workpiece rotation during the rotation process is larger, the coaxiality of the workpiece is worse, and the cutting force generated is easy to cause the deformation of the ultra-fine long stainless steel pipe.

[0060] To solve the above problems, the application provides a processing device for the breaking groove of an ultra-fine long stainless steel pipe, which comprises a tool electrode installed on a machine tool, a bearing assembly for clamping the stainless steel pipe, and a driving assembly for controlling the movement state of the tool electrode.

[0061] Among them, 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 stainless steel pipe 6, and the same electric spark machining point comprises a working state and a non-working state.

[0062] 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 the non-working state.

[0063] 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 the working state.

[0064] The threshold value is the discharge distance between the electric spark machining point and the surface to be processed that meets the processing requirements. For example, the distance is 0-50μm.

[0065] Among them, the working state of the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe 6 realizes the processing of the breaking groove on the surface to be processed.

[0066] It can be understood that the discharge end 101 comprises a plurality of electric spark machining points arranged circumferentially around the stainless steel pipe, and the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe can be continuously and uninterruptedly distributed circumferentially around the stainless steel pipe, or can be discontinuously distributed circumferentially around the stainless steel pipe, which can realize the continuous processing and forming of the breaking groove on the surface to be processed.

[0067] In one possible implementation, one end of the tool electrode 1 is in the form of a circular ring, that is, the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe form a continuous circular ring, such as Figures 2-7As shown, the inner circular end of the circular ring is matched with the shape of the breaking groove 601, that is, the inner circular end is convex, and the breaking groove 601 is concave, and the cross-sectional size of the convex is the same as the cross-sectional shape of the concave; the other end of the tool electrode 1 is a conductive end 104, which is electrically connected with an output end of a power supply device arranged on a machine tool, so as to introduce current and transmit the current to the inner circular end, at this time, the inner circular end is a discharge end 101, so as to realize the machining of the breaking groove on the surface to be machined by the working state of the plurality of circumferentially arranged electric spark machining points of the discharge end 101.

[0068] In a possible implementation, the discharge end is of a rigid structure, and the discharge end 101 is sleeved on the outer end surface of the stainless steel pipe 6; during machining, the stainless steel pipe 6 is electrically connected with 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 pipe 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 end surface to be machined of the stainless steel pipe 6 is constantly changing; 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, at this time, the electric spark machining point is a non-working end 103; 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, at this time, the electric spark machining point is a working end 102, so as to realize the transition of the working state and the non-working state of the same electric spark machining point, and the working states of all the electric spark machining points collectively realize the 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 pipe for one revolution, and all the working ends form a continuous circular ring-shaped discharge end around the stainless steel pipe, so as to avoid the discharge end 101 of the tool electrode 1 in a continuous machining state, and further reduce the loss of the tool electrode 1.

[0069] wherein, the circular ring-shaped discharge end 101 of the tool electrode 1 includes a plurality of working ends 102 distributed in a ring shape, and the plurality of working ends 102 are in a non-synchronous and non-continuous machining state when the discharge end moves eccentrically around the central axis of the inner cavity of the stainless steel pipe 6 for machining; and the machining tracks of the plurality of working ends collectively constitute the breaking groove of the stainless steel pipe 6.

[0070] 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 fracture 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 the machining of all the working ends 102 is realized alternately and orderly, 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.

[0071] Compared with the prior art, in the machining process, the tool electrode 1 does not contact the surface of the stainless steel pipe 6, so that the deformation of the tool electrode 1 is avoided, and in the machining process, the stainless steel pipe 6 does not need to move, so that the fracture groove 601 in the annular shape is machined on the outer surface of the stainless steel pipe 6, and the problem that the machining precision is affected due to the poor coaxiality of the stainless steel pipe 6 in the rotation process is overcome; and the tool electrode 1 is eccentrically moved around the central axis in the inner cavity of the stainless steel pipe 6 for one cycle, so that the machining of the fracture groove 601 of the stainless steel pipe is completed, the machining is realized in place at one time, and the machining efficiency is significantly improved; and the discharge end 101 of the tool electrode 1 is in the shape 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 distance is closer for the working end 102, and the distance is farther for the non-working end 103, and 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, 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 in the continuous machining state, the loss of the tool electrode 1 is greatly reduced, the tool electrode loss is ≤1%, and the deformation of the working end face of the tool electrode 1 is reduced, so that the machining precision of the fracture groove 601 of the super-thin long stainless steel pipe is improved.

[0072] 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, if yes, the discharge end 101 is the non-working end 103. In this way, through the dynamic change between the working end 102 and the non-working end 103, the discharge end 101 of the tool electrode 1 is avoided in the continuous machining state, so as to reduce the loss of the tool electrode 1.

[0073] Specifically, one end of the tool electrode 1 is installed on a machine tool, the discharge end 101 of the tool electrode 1 is sleeved on the outer end surface 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 in the inner cavity of the stainless steel pipe 6, and there is a surplus gap between the discharge end 101 and the outer end surface of the stainless steel pipe 6, that is, the diameter size of the inner circular end of the discharge end 101 is greater than the outer diameter size of the stainless steel pipe 6, for example, the diameter of the inner circular end is 10-20mm, 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 the electric spark machining. During machining, the tool electrode 1 is driven to swing 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 in the inner cavity of the stainless steel pipe 6.

[0074] wherein the single-sided feed amount O1O2 satisfies:

[0075] O1O2=S1+(H1-H2)-S2

[0076] wherein O1 represents the center point of the discharge end 101 of the tool electrode;

[0077] O2 represents the center point of the inner cavity of the stainless steel pipe 6;

[0078] H1 is the wall thickness of the stainless steel pipe 6;

[0079] H2 is the wall thickness of the fracture groove 601;

[0080] S2 is the machining gap, that is, the closest distance between the working end 102 and the end surface of the stainless steel pipe 601 when the tool electrode 1 is in eccentric motion;

[0081] S1 is the surplus gap between the discharge end 101 and the outer end surface of the stainless steel pipe 6.

[0082] wherein S1 satisfies:

[0083]

[0084] wherein, as shown in Figure 5 S 11 , S 12 , S 13 , S 14 are actual surplus gap values between four points selected on the discharge end 101 of the tool electrode and the outer end surface of the stainless steel pipe 6, and the four points are uniformly distributed on the discharge end 101.

[0085] For example, S 11 , S 12 , S 13 , S 142.055mm, 2.060mm, 2.065mm, 2.050mm, and S1=2.058mm.

[0086] Wherein, the processing gap S2 is 10-50μm to meet the requirements of electric spark machining.

[0087] For example, S2=10μm, H1=0.5mm, H2=0.3mm, and S1=2.058mm, and O1O2=2.248mm.

[0088] Wherein, 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 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.

[0089] Wherein, after 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 pipe 6 by adjusting the machine tool, the four values of S 11 , S 12 , S 13 , S 14 are measured. The closer the four values are, the more accurate the value of S1 is, and the more accurate the unilateral feed amount O1O2 is. Thus, during the eccentric motion of the tool electrode 1, the processing gap accuracy can be ensured, and the processing depth of the working end 101 can be ensured to ensure the size accuracy of the breaking groove 601.

[0090] Wherein, after 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 pipe 6, the tool electrode 1 is in an eccentric motion state under the action of the machine tool. The detailed process is as follows.

[0091] 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.

[0092] The tool electrode 1 is moved so that O1 is away from O2 by the same distance as the unilateral feed amount O1O2. At this time, the distance between O1 and O2 is O1O2.

[0093] O1 is rotated around O2 with O1O2 as the radius. At this time, the trajectory of O1 is a circle, as shown in Figure 8 , the center of the circle is O2, and the radius is O1O2.

[0094] In the process of moving O1, when the closest distance between the end face of the discharge end 101 and the surface of the stainless steel pipe 6 reaches 10 μm, the power supply device is started 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 moves in a circumferential motion around O2.

[0095] In order to further illustrate the motion trajectory of the tool electrode 1, an arbitrary point O3 on the discharge end 101 is selected, and the trajectory of O3 is described as follows:

[0096] The tool electrode 1 is moved so that O3 moves towards O2 by a distance of O1O2;

[0097] When O1 rotates around O2, at this time, as shown in Figure 9 , the trajectory of O3 is a circle with the initial position of O3 as the center and O1O2 as the radius;

[0098] In the process of moving 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 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 moving distance of O3 reaches O1O2, and then O3 moves in a circumferential motion around its initial position.

[0099] In this way, in the process of eccentric motion 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, i.e. 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.

[0100] In the process of eccentric motion of the tool electrode 1, the distance between the inner circular end face of the discharge end 101 and the outer end face 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, i.e. 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.

[0101] The conductive end of the tool electrode 1 is electrically connected with one output end of a power supply device arranged on the machine tool, and the stainless steel pipe 6 is electrically connected with another output end of the power supply device, wherein the power supply device comprises a pulse power supply, and the two output ends of the pulse power supply are respectively connected with the positive and negative poles of the pulse power supply to output pulse voltage.

[0102] Exemplarily, in the process of machining, the electrical parameters satisfy:

[0103] 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.

[0104] Specifically, the driving assembly comprises a transmission rod 2, one end of the transmission rod 2 is connected with the tool electrode 1, and the other end of the transmission rod 2 is installed on the machine tool, and the transmission rod 2 can be controlled to swing through the machine tool, so as to drive the discharge end 101 of the tool electrode 1 to make eccentric motion around the central axis of the inner cavity of the stainless steel pipe 6.

[0105] Specifically, the transmission rod 2 swings clockwise in the swing plane ZY, and the swing plane ZY is parallel to the plane where the discharge end 101 is located, so as to realize the eccentric motion of the discharge end of the tool electrode 1 around the central axis of the inner cavity of the stainless steel pipe 6. In the process of machining, the stainless steel pipe 6 remains stationary.

[0106] Exemplarily, in the process of machining, the non-electrical parameters satisfy:

[0107] 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.

[0108] Specifically, the bearing assembly comprises an equal-height positioning block 3 and an auxiliary supporting block 4 installed on the machine tool, so as to place the stainless steel pipe 6 on the equal-height positioning block 3 and the auxiliary supporting block 4 to clamp the stainless steel pipe 6.

[0109] Specifically, as shown in Figure 1 two equal-height positioning blocks 3 are arranged on both sides of the position to be machined of the stainless steel pipe 6, so as to ensure the stability of the position to be machined of the stainless steel pipe 6 in the process of machining. Exemplarily, the distance between the two equal-height positioning blocks 3 is 20-50mm.

[0110] Specifically, two auxiliary supporting blocks 4 are arranged, and the two equal-height positioning blocks 3 are located between the two auxiliary supporting blocks 4, so as to support and position the two ends of the stainless steel pipe 6 through the two auxiliary supporting blocks 4, and further ensure the stability of the stainless steel pipe 6 in the process of machining.

[0111] wherein, as shown in Figures 10-12As shown, the upper end faces of the above-mentioned equal-height positioning blocks 3 and auxiliary bearing blocks 4 are flush, the upper end faces of the equal-height positioning blocks 3 and auxiliary bearing blocks 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.

[0112] Further, the equal-height positioning blocks 3 are further provided with clamping plates 5, the clamping plates 5 cover the V-shaped grooves and are clamped on the equal-height positioning blocks 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 5-10 mm.

[0113] Wherein, before placing the stainless steel pipe 6 on the equal-height positioning blocks 3, the tool electrode 1 needs to be first aligned, 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 the equal-height positioning blocks 3, auxiliary bearing blocks 4 and clamping plates 5, and the stainless steel pipe 6 is aligned by the equal-height positioning blocks 3 and auxiliary bearing blocks 4.

[0114] Specifically, after the tool electrode 1 is aligned, the positions of the equal-height positioning blocks 3 and auxiliary bearing blocks 4 on the machine tool are adjusted by the machine tool XYZ axis to align the stainless steel pipe 6, so as to ensure 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 O1O2 and further improve the machining precision.

[0115] Wherein, the alignment process of the stainless steel pipe 6 is as follows.

[0116] First, two equal-height positioning blocks 3 and 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 a dial indicator, and the parallelism error is ≤0.01mm.

[0117] Wherein, one end of the transmission rod 2 is connected with the tool electrode 1 and parallel to the center line of the discharge end 101 of the tool electrode 1; during the machining process, the other end of the transmission rod 2 is installed on the machine tool to drive the transmission rod 2 to swing through the machine tool, and then the tool electrode 1 is moved through the transmission rod 2 to realize the eccentric motion of the discharge end 101 of the tool electrode 1 around the inner cavity center axis of the stainless steel pipe 6.

[0118] In this way, the discharge end 101 of the tool electrode 1 eccentrically moves around the inner cavity center axis 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 and significantly improving the machining efficiency.

[0119] In addition, the present application also provides a machining method for an ultra-long stainless steel pipe breaking groove, which comprises electric spark machining of the stainless steel pipe breaking groove by using the above-mentioned machining device, so as to solve the problem that it is difficult to realize high-precision machining of the breaking groove on the ultra-long stainless steel pipe.

[0120] Specifically, the method comprises using the working state of the plurality of electric spark machining point positions circumferentially arranged around the stainless steel pipe of the tool electrode 1 to realize the machining of the breaking groove on the surface to be machined.

[0121] The one end of the tool electrode is a discharge end, and the discharge end comprises a plurality of electric spark machining point positions circumferentially arranged around the stainless steel pipe. The same electric spark machining point position comprises a working state and a non-working state.

[0122] When the distance between the electric spark machining point position and the surface to be machined is greater than the threshold value, the electric spark machining point position is in the non-working state.

[0123] When the distance between the electric spark machining point position and the surface to be machined is less than or equal to the threshold value, the electric spark machining point position is in the working state.

[0124] The threshold value is the discharge distance between the electric spark machining point position and the surface to be machined that meets the machining requirement. Exemplarily, the distance is 0-50 μm.

[0125] The discharge end 101 comprises a plurality of electric spark machining point positions circumferentially arranged around the stainless steel pipe. The plurality of electric spark machining point positions circumferentially arranged around the stainless steel pipe can be continuously and uninterruptedly distributed circumferentially around the stainless steel pipe, or can be discontinuously distributed circumferentially around the stainless steel pipe, and can realize the continuous machining and forming of the breaking groove on the surface to be machined.

[0126] In one possible implementation, the one end of the tool electrode 1 is in the shape of a circular ring, that is, the plurality of electric spark machining point positions circumferentially arranged around the stainless steel pipe form a continuous circular ring. The inner circular end of the circular ring matches the shape of the breaking groove 601, that is, the inner circular end is in the shape of a protrusion, and the breaking groove 601 is in the shape of a groove. The cross-sectional size of the protrusion is the same as the cross-sectional shape of the groove. 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 electric current and transmitting the electric current to the inner circular end. At this time, the inner circular end is the discharge end 101, so as to realize the machining of the breaking groove on the surface to be machined by the working state of the plurality of electric spark machining point positions circumferentially arranged around the stainless steel pipe of the discharge end 101.

[0127] In a possible implementation, the discharge end is of a rigid structure, and the discharge end 101 is sleeved on the outer end surface of the stainless steel pipe 6; during machining, the stainless steel pipe 6 is electrically connected to another output end of the power supply device, and the tool electrode 1 moves eccentrically around the central axis in the inner cavity of the stainless steel pipe 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 end surface to be machined of the stainless steel pipe 6 is constantly changing; 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, at this time, the electric spark machining point is the non-working end 103; 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, at this time, the electric spark machining point is the working end 102; in this way, the working state and the non-working state of the same electric spark machining point are realized, and the working states of all the electric spark machining points together realize the 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 in the inner cavity of the stainless steel pipe for one revolution, and all the working ends form a continuous annular discharge end around the circumference of the stainless steel pipe, 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.

[0128] The circular discharge end 101 of the tool electrode 1 includes a plurality of working ends 102 distributed in a ring shape, and the plurality of working ends 102 are in a non-synchronous and non-continuous machining state when the discharge end moves eccentrically around the central axis in the inner cavity of the stainless steel pipe 6 for machining; and the machining tracks of the plurality of working ends together form the breaking groove of the stainless steel pipe 6.

[0129] The machining tracks of the plurality of working ends together form the breaking groove of the stainless steel pipe 6.

[0130] Specifically, the tool electrode 1 is installed on a machine tool, and during machining, the machine tool drives the tool electrode 1 to move eccentrically, so that the discharge end 101 of the tool electrode performs electric spark machining around the end surface of the stainless steel pipe 6, and the machining direction 7 is the circumferential direction of the outer end surface of the stainless steel pipe 6, and the center line of the circumferential direction coincides with the central axis in the inner cavity of the stainless steel pipe 6.

[0131] Specifically, before the eccentric motion of the tool electrode 1, the center of the inner circular end of the discharge end 101 of the tool electrode 1 needs to be adjusted to coincide with the central axis of the stainless steel pipe 6, and the discharge end 101 has a clearance gap with 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 larger 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 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 the electric spark machining.

[0132] wherein the single-sided feed amount O1O2 satisfies:

[0133] O1O2=S1+(H1-H2)-S2

[0134] wherein O1 represents the center point of the discharge end 101 of the tool electrode 1;

[0135] O2 represents the center point of the inner cavity of the stainless steel pipe 6;

[0136] H1 is the wall thickness of the stainless steel pipe 6;

[0137] H2 is the wall thickness of the fracture groove 601;

[0138] S1 is the clearance gap between the discharge end 101 and the outer end surface of the stainless steel pipe 6;

[0139] S2 is the machining gap, that is, the closest distance between the working end 102 and the end surface of the stainless steel pipe 601 when the tool electrode 1 is eccentrically moved.

[0140] wherein S1 satisfies:

[0141]

[0142] wherein S 11 , S 12 , S 13 , S 14 are actual clearance gap values between the four points selected on the discharge end 101 of the tool electrode 1 and the outer end surface of the stainless steel pipe 6, and the four points are uniformly distributed on the discharge end 101.

[0143] For example, S 11 , S 12 , S 13 , S 14 are 2.055mm, 2.060mm, 2.065mm, and 2.050mm, respectively, and S1=2.058mm at this time.

[0144] wherein the machining gap S2 is 10-50μm to meet the requirements of electric spark machining.

[0145] Exemplary, S2 = 10 μm; H1 = 0.5 mm, H2 = 0.3 mm, S1 = 2.058 mm, at this time, O1O2 = 2.248 mm.

[0146] Wherein, S can be measured by using the automatic centering module on the machine tool 11 , S 12 , S 13 , S 14 , wherein, if the four values are equal, that is, the center of the inner circle end of the discharge end 101 of the tool electrode 1 coincides with the central axis in the inner cavity of the stainless steel pipe 6.

[0147] Wherein, after adjusting the tool electrode 1 to make the center of the discharge end 101 coincide with the central axis in the inner cavity of the stainless steel pipe 6 by using the machine tool, the four values of S 11 , S 12 , S 13 , S 14 are measured. The closer the four values of S 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 the eccentric motion of the tool electrode 1, and the machining depth of the working end 102 is ensured to ensure the size accuracy of the broken groove 601 machined.

[0148] Specifically, after adjusting the tool electrode 1 to make the center of the discharge end 101 coincide with the central axis in the inner cavity of the stainless steel pipe 6, the tool electrode 1 is driven by the machine tool to make eccentric motion, and the detailed process is as follows.

[0149] The movement trajectory 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 is described as follows:

[0150] The tool electrode 1 is moved so that O1 is away from O2 by the same distance as the unilateral feed amount O1O2, at this time, the distance between O1 and O2 is O1O2;

[0151] O1 is rotated around O2 with O1O2 as the radius, at this time, the trajectory of O1 is a circle, the center of the circle is O2, and the radius is O1O2;

[0152] Wherein, during the movement of O1, when the nearest 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.

[0153] 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:

[0154] The tool electrode 1 is moved so that O3 moves towards O2 by a distance O1O2;

[0155] When O1 rotates around O2, the locus of O3 is a circle with O3's initial position as the center and O1O2 as the radius;

[0156] In the process of moving O3, when the distance between the end surface 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 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 moving distance of O3 reaches O1O2, and then O3 makes a circular motion with its initial position as the center.

[0157] In this way, in the process of eccentric motion of the tool electrode 1, the distance between the inner circular end surface of the discharge end 101 and the outer surface of the stainless steel pipe 6 changes constantly, and the distance between each part of the inner circular end surface of the discharge end 101 and the outer end surface of the stainless steel pipe 6 changes from close to far, and then the discharge end 101 changes from the working state to the non-working state, i.e., the dynamic change between the working end 102 and the non-working end 103 is realized.

[0158] In this way, in the process of eccentric motion of the tool electrode 1, the distance between the inner circular end surface of the discharge end 101 and the outer surface of the stainless steel pipe 6 changes constantly, and the distance between each part of the inner circular end surface of the discharge end 101 and the outer end surface of the stainless steel pipe 6 changes from close to far, and then the discharge end 101 changes from the working state to the non-working state, i.e., the dynamic change between the working end 102 and the non-working end 103 is realized.

[0159] In this way, in the process of eccentric motion of the tool electrode 1, the distance between the inner circular end surface of the discharge end 101 and the outer surface of the stainless steel pipe 6 changes constantly, and the distance between each part of the inner circular end surface of the discharge end 101 and the outer end surface of the stainless steel pipe 6 changes from close to far, and then the discharge end 101 changes from the working state to the non-working state, i.e., the dynamic change between the working end 102 and the non-working end 103 is realized.

[0160] In the process of 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 pulse voltage is applied to the discharge end 101 and the stainless steel pipe 6, the liquid medium at the closest point between the discharge end 101 and the stainless steel pipe 6 at that time is broken down to form a discharge channel. Since the cross-sectional area of the channel is very small, the discharge time is very short, resulting in a high concentration of energy (10 6 W / cm 2), the transient high temperature generated by the discharge region is enough 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 is discharged again at the nearest point between the other two poles after a very short interval, and so on, the tool electrode 1 continuously feeds the stainless steel pipe 6, and the shape of the tool electrode 1 is finally copied on the stainless steel pipe 6 to form the required machined surface; during the machining process, although a small part of the total energy is also released to the tool electrode 1, causing the tool electrode 1 to be worn, but by eccentrically moving 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, thereby reducing the wear of the tool electrode 1 by avoiding continuous machining of the working end 102, and further, the working end 102 of the discharge end 101 maintains a relatively complete shape at each moment of machining, improving the machining precision.

[0161] For example, during the machining process, the electrical parameters satisfy:

[0162] 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.

[0163] Specifically, during machining, the tool electrode 1 is eccentrically moved by the machine tool, and the stainless steel pipe 6 remains stationary.

[0164] Specifically, during machining, the tool electrode 1 is eccentrically moved by the machine tool, and the stainless steel pipe 6 remains stationary.

[0165] Specifically, the transmission rod 2 rotates clockwise in the swing plane ZY, and the swing plane ZY is parallel to the plane where the discharge end 101 is located, so as to realize the eccentric movement of the tool electrode 1 around the central axis of the inner cavity of the stainless steel pipe 6.

[0166] For example, during the machining process, the non-electrical parameters satisfy:

[0167] The swing speed of the transmission rod 2 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.

[0168] Specifically, 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.

[0169] Wherein, the two equal height positioning blocks 3 are used to clamp the two sides of the position to be processed of the stainless steel pipe 6, so as to ensure the stability of the position to be processed of the stainless steel pipe 6 during processing. For example, the distance between the two equal height positioning blocks 3 is 30mm.

[0170] Wherein, the two equal height positioning blocks 3 are located between the two auxiliary bearing blocks 4, and the two auxiliary bearing blocks 4 are used to support and position the two ends of the stainless steel pipe 6, so as to further ensure the stability of the stainless steel pipe 6 during processing.

[0171] Wherein, the upper end faces of the equal height positioning blocks 3 and the auxiliary bearing blocks 4 are flush, and the upper end faces of the equal height positioning blocks 3 and the auxiliary bearing blocks 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.

[0172] Further, the clamping plate 5 is covered on the V-shaped groove and clamped on the equal height positioning block 3 to limit the stainless steel pipe 6 and further improve the stability of the stainless steel pipe 6. For example, the angle of the V-shaped groove is 60°-90°, and the depth is 5-10mm.

[0173] Wherein, before placing the stainless steel pipe 6 on the equal height positioning block 3, the tool electrode 1 needs to be first aligned by the machine tool, 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 the equal height positioning block 3 and the auxiliary bearing block 4, and the stainless steel pipe 6 is aligned by the equal height positioning block 3 and the auxiliary bearing block 4.

[0174] 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 to align the stainless steel pipe 6, so as to ensure 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 O1O2, and further improve the machining precision.

[0175] Wherein, the alignment process of the stainless steel pipe 6 is as follows.

[0176] First, fix the two equal height positioning blocks 3 and the two auxiliary support blocks 4 on the workbench 9 of the machine tool, and then use the dial indicator to align the side surface parallel to the machine tool X axis, and the parallelism error is ≤0.01mm.

[0177] Before placing the stainless steel pipe 6 on the equal height positioning block 3, first insert 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 bearing block 4, so as to align the stainless steel pipe 6 by the equal height positioning block 3 and the auxiliary bearing block 4.

[0178] The one end of the transmission rod 2 is connected with the tool electrode 1, and is parallel with the center line of the discharging 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 to move through the transmission rod 2, and realize the eccentric motion of the discharging end 101 of the tool electrode 1 around the inner cavity central axis of the stainless steel pipe 6.

[0179] In this way, the discharging end 101 of the tool electrode 1 eccentrically moves around the inner cavity central axis of the stainless steel pipe 6 for one circle, and the machining of the breaking groove 601 of the stainless steel pipe is completed, the machining is in place once, and the machining efficiency is improved significantly.

[0180] Compared with the prior art, the tool electrode 1 is used for discharging and etching the metal on the surface of the ultra-thin long stainless steel pipe 6 to machine the breaking groove 601, that is, the tool electrode 1 does not contact the surface of the ultra-thin long stainless steel pipe in the process of machining, and the deformation of the ultra-thin long stainless steel pipe is avoided, and the damage of the cutting force to the ultra-thin long stainless steel pipe is overcome.

[0181] The tool electrode 1 is used for eccentrically moving around the inner cavity central axis of the ultra-thin long stainless steel pipe to machine the breaking groove 601 of the ultra-thin long stainless steel pipe, that is, the ultra-thin long stainless steel pipe does not need to move in the process of machining, and the annular breaking groove 601 can be machined on the outer surface of the ultra-thin long stainless steel pipe, and the problem that the coaxiality of the ultra-thin long stainless steel pipe is poor in the process of rotation and affects the machining precision is overcome.

[0182] In the process of machining, the ultra-thin long stainless steel pipe is only needed to be 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 ultra-thin long stainless steel pipe is limited by the clamping plate 5, so that the clamping and positioning of the ultra-thin long stainless steel pipe are realized, the clamping is convenient, and the stability of the ultra-thin long stainless steel pipe 6 in the process of machining is ensured.

[0183] The discharge end 101 of the tool electrode 1 of the application is circular ring-shaped, 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 processed 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 in a 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 breaking groove 601 of the super-long stainless steel pipe is improved.

[0184] The discharge end 101 of the tool electrode 1 of the application is eccentrically moved around the inner cavity central axis of the super-long stainless steel pipe 6 for one cycle, 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.

[0185] By eccentrically moving the discharge end 101 of the tool electrode 1 around the inner cavity central axis of the stainless steel pipe 6, the single-sided feed amount of each end surface of the discharge end 101 can be the same, so that the consistency of the machining depth of the breaking groove 601 is ensured, and the machining precision of the breaking groove 601 is improved.

[0186] The discharge end 101 of the tool electrode 1 is in the shape of a convex, and the breaking groove 601 is in the shape of a groove, and the cross-sectional size of the convex is the same as the cross-sectional shape of the groove, so that after the discharge end 101 of the tool electrode 1 is eccentrically moved around the inner cavity central axis of the super-long stainless steel pipe 6 for one cycle, the depth and the inclined angle of the machined breaking groove 601 are the required depth and inclined angle of the breaking groove 601, and the machining precision is significantly improved.

[0187] By adjusting the value of the single-sided feed amount, the breaking 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 size of the different inclined angles α can be machined, which lays a foundation for rapid production and batch production of products.

[0188] The discharge end 101 of the tool electrode 1 of the application is eccentrically sleeved on the super-fine long stainless steel pipe 6. During machining, the distance between the discharge end 101 and the super-fine long stainless steel pipe 6 changes from large to small and then from small to large. During the change 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 the working liquid. During the change 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 the metal scraps, thereby avoiding the accumulation of the metal scraps at the discharge end 101 due to the delayed discharge of the metal scraps, 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.

[0189] By eccentrically sleeving the discharge end 101 of the tool electrode 1 on the super-fine long stainless steel pipe 6, the metal scraps can be efficiently discharged, and the electric spark machining can be performed with a small machining gap. In this way, the machining current and voltage value can be reduced, the machining cost can be reduced, and the fracture groove 601 with a low surface roughness can be obtained.

[0190] Embodiment 1

[0191] A machining device for a fracture groove of a super-fine long stainless steel pipe includes a tool electrode 1, a bearing assembly, and a driving assembly installed on a machine tool. The bearing assembly is used to clamp the stainless steel pipe 6, and the driving assembly is used to drive the tool electrode 1 to eccentrically move around the central axis of the inner cavity of the stainless steel pipe 6, so as to perform electric spark machining on the fracture groove 601 of the stainless steel pipe, thereby solving the problem that it is difficult to machine the fracture groove on the super-fine long stainless steel pipe.

[0192] Specifically, one end of the tool electrode 1 is in the shape of a circular ring, the inner circular end of the circular ring is the same as the shape of the fracture groove 601, and the other end of the tool electrode 1 is a conductive end 104 electrically connected with an output end of a power supply device arranged on the machine tool, for introducing electric current and transmitting the electric current to the inner circular end. At this time, the inner circular end is a discharge end 101 sleeved on the outer end surface of the stainless steel pipe 6. During machining, the stainless steel pipe 6 is electrically connected with another output end of the power supply device, and 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. At this time, the discharge end 101 includes a working end 102 and a non-working end 103, so as to use the working end 102 to discharge and remove the metal on the surface of the stainless steel pipe 6 during machining.

[0193] 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 of the stainless steel pipe 6 to be machined is constantly changing, the distance of 10-50μm is the working state, that is, the working end 102, and the distance greater than 50μm is the non-working state, that is, the non-working end 103. Wherein, all the working end 102 machining tracks together constitute the ultra-fine stainless steel pipe breaking groove 601.

[0194] Wherein, the center of the inner circle end of the discharge end 101 of the tool electrode 1 coincides with the inner cavity axis of the stainless steel pipe 6, and there is a clearance gap between the discharge end 101 and the outer end face of the stainless steel pipe 6, wherein the end face diameter of the discharge end 101 is 20mm, which is 10 times the outer diameter of the stainless steel pipe 6, so as to facilitate the determination of the value of the single-sided feed amount O1O2; during machining, the tool electrode 1 is driven by the driving assembly to swing, at this time, the discharge end 101 of the tool electrode 1 is in eccentric motion state around the inner cavity axis of the stainless steel pipe 6.

[0195] Wherein, the automatic centering module on the machine tool is used to measure S 11 , S 12 , S 13 , S 14 2.055mm, 2.060mm, 2.065mm, 2.050mm, at this time, S1=2.058mm.

[0196] Wherein, S2=10μm; H1=0.5mm, H2=0.3mm, S1=2.058mm, at this time, O1O2=2.248mm.

[0197] Wherein, after adjusting the center of the discharge end 101 of the tool electrode 1 to coincide with the inner cavity axis of the stainless steel pipe 6, the tool electrode 1 is in eccentric motion state under the action of the driving assembly.

[0198] Wherein, the conductive end 104 of the tool electrode 1 is electrically connected with the output end of the power supply device arranged on the machine tool, and the stainless steel pipe 6 is electrically connected with the other output end of the power supply device, wherein the power supply device includes a pulse power source, and the two output ends thereof are respectively connected with the positive and negative poles of the pulse power source for outputting pulse voltage.

[0199] Wherein, during machining, the electrical parameters meet:

[0200] Pulse width 40μs, pulse interval 26μs, average machining current 1A, average machining voltage 40V.

[0201] Specifically, the driving assembly includes a transmission rod 2, one end of the transmission rod 2 is connected with the tool electrode 1, 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 make eccentric motion around the inner cavity axis of the stainless steel pipe 6. Wherein, during processing, the non-electric parameter satisfies:

[0202] Wherein, during processing, the non-electric parameter satisfies:

[0203] The swing speed of the transmission rod 2 is 0.5 rpm, the processing gap S2 is 10 μm, the processing speed is 0.04 g / min, and the single-sided feed amount O1O2 is 2.248 mm.

[0204] Specifically, the bearing assembly includes an equal-height positioning block 3 and an auxiliary supporting block 4 installed on the machine tool, so as to place the stainless steel pipe 6 on the equal-height positioning block 3 and the auxiliary supporting block 4, and clamp the stainless steel pipe 6.

[0205] Wherein, two equal-height positioning blocks 3 are provided, and the two equal-height positioning blocks 3 are located on both sides of the to-be-processed position of the stainless steel pipe 6, and the distance between the two equal-height positioning blocks 3 is 30 mm.

[0206] Wherein, two auxiliary supporting blocks 4 are provided, and the two equal-height positioning blocks 3 are located between the two auxiliary supporting blocks 4, so as to support and position the two ends of the stainless steel pipe 6 through the two auxiliary supporting blocks 4.

[0207] Wherein, the upper end faces of the equal-height positioning block 3 and the auxiliary supporting block 4 are flush, and the upper end faces of the equal-height positioning block 3 and the auxiliary supporting 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.

[0208] 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. The angle of the V-shaped groove is 90°, and the depth is 10 mm.

[0209] Wherein, before placing the stainless steel pipe 6 on the equal-height positioning block 3, first, the tool electrode 1 needs to be centered, then the stainless steel pipe 6 is inserted into the discharge end 101 of the tool electrode 1, and finally the equal-height positioning block 3, the auxiliary supporting block 4 and the clamping plate 5 are used to clamp the stainless steel pipe 6, and the equal-height positioning block 3 and the auxiliary supporting block 4 are used to center the stainless steel pipe 6.

[0210] Wherein, one end of the transmission rod 2 is connected with the tool electrode 1, and is parallel with 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 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 inner cavity central axis of the stainless steel pipe 6.

[0211] In this way, the discharge end 101 of the tool electrode 1 eccentrically moves around the inner cavity central axis of the stainless steel pipe 6 for one cycle, so that the machining of the stainless steel pipe breaking groove 601 is completed, the machining is realized in place at one time, and the machining efficiency is significantly improved.

[0212] Embodiment 2

[0213] A machining method of a super-fine long stainless steel pipe breaking groove, comprising the following steps:

[0214] Step 1: adjusting the position of the tool electrode 1 by the machine tool, so that the plane where the discharge end 101 of the tool electrode 1 is located is perpendicular to the workbench surface 9 of the machine tool;

[0215] Specifically, the workbench surface 9 of the machine tool is a horizontal plane, the tool electrode 1 is vertically installed on the machine tool, and is connected with the transmission rod installed on the machine tool.

[0216] Step 2: clamping the stainless steel pipe 6 by the bearing assembly, and aligning the stainless steel pipe 6;

[0217] Specifically, first, two pieces of the equal-height positioning block 3 and two pieces of the auxiliary supporting block 4 are fixed on the workbench 9, the parallelism of the side surface of the equal-height positioning block 3 and the X-axis of the machine tool is found by using a dial indicator, and the position of the equal-height positioning block 3 and the auxiliary supporting block 4 is adjusted by the machine tool, wherein the parallelism error is ≤0.01mm.

[0218] Then, the stainless steel pipe 6 is placed on the equal-height positioning block 3, and before being placed, the stainless steel pipe 6 is first inserted into the inner circle end of the lower end of the tool electrode 1, and the equal-height positioning block 3 is used to ensure that the stainless steel pipe 6 is in a horizontal position, and the distance between the two equal-height positioning blocks 3 is 30mm;

[0219] Then, the two ends of the stainless steel pipe 6 are placed on the auxiliary supporting block 4, and finally fixed by the clamping plate 5.

[0220] Step 3: adjusting the center line of the discharge end 101 of the tool electrode 1 to coincide with the inner cavity central axis of the stainless steel pipe 6 by the machine tool;

[0221] Specifically, first, the position of the stainless steel pipe 6 is adjusted by moving the bearing assembly in the X-axis direction of the machine tool, so that the position to be machined of the stainless steel pipe 6 is located in the discharge end 101 of the tool electrode 1;

[0222] Then, the automatic centering module of the machine tool is used to measure S11 12 13 14 The numerical 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 inner cavity axis of the stainless steel pipe 6, if not, the position of the bearing assembly is continuously adjusted by the machine tool until the requirement is met.

[0223] Step 4: The tool electrode 1 is used to carry out electric spark machining on the stainless steel pipe 6 in the working fluid of kerosene and water.

[0224] S101: Control the eccentric movement of the discharge end 101 of the tool electrode 1 around the inner cavity axis of the stainless steel pipe 6;

[0225] Specifically, the machine tool drives the transmission rod 2 to swing in the YZ plane, and then controls the discharge end 101 of the tool electrode 1 to move eccentrically around the inner cavity axis of the stainless steel pipe 6 through the transmission rod 2. The eccentric movement direction 8 is as shown in Figure 9

[0226] The swing speed of the transmission rod 2 is 0.5 rpm.

[0227] 11 12 13 14 The actual measured values are 2.055 mm, 2.060 mm, 2.065 mm, and 2.050 mm, and at this time, S1=2.058 mm;

[0228] The processing gap S2 is 10 μm.

[0229] The single-sided feed amount O1O2=S1+(H1-H2)-S2=2.058+(0.5-0.3)-0.01=2.248 mm.

[0230] The processing speed is 0.04 g / min.

[0231] S102: When the tool electrode 1 moves eccentrically, the tool electrode 1 is powered to carry out electric spark machining.

[0232] Specifically, the electrical parameters meet:

[0233] The pulse width is 40 μs, the pulse interval is 26 μs, the average processing current is 1 A, and the average processing voltage is 40 V.

[0234] The above processing method is used to process the fracture grooves of #01-#10 pieces of ultra-fine long stainless steel pipes, and the processing parameters are shown in Table 1.

[0235] Table 1 Processing parameters ​​​​​​​​

[0236]

[0237] Processing requirements: the thickness of the broken groove wall is 0.3±0.05mm, and the bevel angle α is 90°.

[0238] The detection results are shown in Table 2.

[0239] Table 2 detection results

[0240]

[0241] Wherein, the electrode consumption ratio is E / W*100%, wherein, E is the discharge end diameter size variation of the tool electrode, and W is the initial diameter size of the inner circle end of the tool electrode.

[0242] As shown in Table 2, the average value of the groove depth of the broken groove of the 10 stainless steel pipes processed by the present application is 0.2146mm, the standard deviation is 0.01427, the dispersion coefficient is 0.07, the broken groove angle is 90°, the average value of the broken 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 processing method of the present application can realize the processing of the broken groove of the ultra-thin long stainless steel pipe, and the processed broken groove has high precision and stability, and the ultra-thin long stainless steel pipe is not damaged, and the tool electrode has small loss.

[0243] 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.

[0244] 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 person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An apparatus for processing a break fluting of an ultra-long stainless steel pipe, characterized by: The tool electrode is installed on a machine tool, the bearing assembly is used for clamping a stainless steel pipe, and the driving assembly is used for controlling the movement state of the tool electrode. 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 stainless steel pipe. The working state of the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe realizes the machining of the breaking groove on the surface to be machined. 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. 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. The threshold value is the discharge distance between the electric spark machining point and the surface to be machined that meets the machining requirement. The circular ring-shaped discharge end of the tool electrode is a rigid structure and is sleeved on the stainless steel pipe. During machining, the tool electrode is controlled to move eccentrically by the machine tool, and the stainless steel pipe remains stationary. The circular ring-shaped discharge end of the tool electrode moves eccentrically around the central axis of the inner cavity of the stainless steel pipe. The machining direction is the circumferential direction of the outer end surface of the stainless steel pipe, and the center line of the circumferential direction coincides with the central axis of the inner cavity of the stainless steel pipe. The driving assembly comprises a transmission rod connected to one end of the tool electrode, and the center line of the discharge end of the tool electrode is parallel to the transmission rod. During machining, the other end of the transmission rod is installed on the machine tool, so that the transmission rod is swung by the machine tool to drive the discharge end of the tool electrode to move eccentrically around the central axis of the inner cavity of the stainless steel pipe. The plurality of electric spark machining points arranged circumferentially around the stainless steel pipe form a continuous circular ring, and the inner circular end of the circular ring matches the shape of the breaking groove.

2. The apparatus of claim 1, wherein: The bearing assembly comprises an equal-height positioning block, an auxiliary bearing block, and a clamping plate installed on the machine tool. The equal-height positioning block and the auxiliary bearing block are used for clamping the stainless steel pipe. The clamping plate is clamped on the equal-height positioning block to limit the stainless steel pipe. The positions of the equal-height positioning block and the auxiliary bearing block on the machine tool are adjustable.

3. The apparatus of claim 2, wherein: The bearing assembly comprises two equal-height positioning blocks and two auxiliary bearing blocks. The two equal-height positioning blocks are respectively located on the two sides of the position to be machined of the stainless steel pipe and between the two auxiliary bearing blocks. The distance between the two equal-height positioning blocks is 20-50 mm.

4. The apparatus of claim 2 or 3, wherein: The upper end surfaces of the equal-height positioning block and the auxiliary bearing block are flush, and V-shaped grooves are formed in the upper end surfaces of the equal-height positioning block and the auxiliary bearing block to place the stainless steel pipe and limit the stainless steel pipe.

5. The apparatus of claim 1, wherein: The plurality of electric spark machining points arranged circumferentially around the stainless steel pipe are continuously and uninterruptedly distributed circumferentially around the stainless steel pipe.

6. A method of processing a break fluting groove of an ultra-long stainless steel pipe, characterized by: The machining device is used for machining the breaking groove of the stainless steel pipe. During machining, 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. During machining, the electric parameters satisfy: 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. The pulse width is 30-60μs, the pulse interval is 20-30μs, the average machining current is 0.8-2A, and the average machining

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