Method for producing super-slim stainless steel pipe with breakage groove

Abstract

The application relates to a production method of an ultra-fine long stainless steel pipe with a broken groove, and belongs to the technical field of ultra-fine long pipe machining, which solves the problem that it is difficult to realize high-precision machining and production of the stainless steel pipe with the broken groove in the prior art. The method comprises the following steps: sleeving a discharge end of a tool electrode on the stainless steel pipe and making eccentric motion around the inner cavity axis of the stainless steel pipe to perform electric spark machining on the broken groove of the stainless steel pipe; and detecting and acquiring the wall thickness of the broken groove of the stainless steel pipe by using an image measuring instrument and comparing the wall thickness with a standard value. High-precision machining of the broken groove of the ultra-fine long stainless steel pipe is realized, and high-precision detection of the wall thickness of the broken groove is realized.

Description

TECHNICAL FIELD

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

[0002] A breaking groove needs to be machined on some ultra-long flight products, which is 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 breaking groove machined thereon is smaller. For the flight product whose size control is crucial, the machining precision requirement of the breaking groove puts forward higher requirements on the machining method.

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

[0004] Therefore, in order to meet the machining needs of the breaking groove on the ultra-long flight product, a new production method of the ultra-long pipe with the breaking groove needs to be explored. SUMMARY

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

[0006] In one aspect, the embodiments of the present application provide a production method of an ultra-long stainless steel pipe with a breaking groove, comprising the following steps:

[0007] Step 1: the discharge end of the tool electrode is sleeved on the stainless steel pipe and makes eccentric motion around the inner cavity axis of the stainless steel pipe, and the electric spark machining is performed on the breaking groove of the stainless steel pipe;

[0008] Step 2: the wall thickness of the breaking groove of the stainless steel pipe is detected and obtained by using an image measuring instrument, and is compared with a standard value.

[0009] Further, the step 2 comprises:

[0010] S21: a sample slice of the stainless steel pipe without the breaking groove is obtained;

[0011] S22: the wall thickness value of the sample slice of the stainless steel pipe is detected and obtained by using the image measuring instrument;

[0012] S23: the machining depth value of the breaking groove of the stainless steel pipe is detected and obtained by using the image measuring instrument;

[0013] S24: Obtain the difference between the wall thickness value of the stainless steel pipe sample slice and the processing depth value of the stainless steel pipe fracture groove, and compare the difference with the fracture groove wall thickness standard value.

[0014] Further, the step 2 further comprises:

[0015] S25: Obtain the oblique angle value of the stainless steel pipe fracture groove using the image measuring instrument, and compare the oblique angle value with the standard value.

[0016] Further, the S21 comprises:

[0017] S211: Align the stainless steel pipe with the fracture groove;

[0018] S212: Cut a 1mm stainless steel pipe sample slice at the end of the stainless steel pipe;

[0019] Wherein the inner cavity axis of the stainless steel pipe is perpendicular to the cutting surface of the stainless steel pipe sample slice.

[0020] Further, the S22 comprises:

[0021] S221: Clean the stainless steel pipe slice:

[0022] S222: Obtain the cutting surface profile of the stainless steel pipe slice using the image measuring instrument;

[0023] S223: Select four points on the cutting surface profile to obtain the wall thickness values of the stainless steel pipe slice at the four points;

[0024] S224: Calculate the average of the wall thickness values of the stainless steel pipe slice at the four points, and take the average as the original wall thickness value of the stainless steel pipe.

[0025] Further, the S23 comprises:

[0026] S231: Align the stainless steel pipe with the fracture groove;

[0027] S232: Obtain the profile of the stainless steel pipe with the fracture groove using the image measuring instrument;

[0028] S233: Measure the outer diameter value of the stainless steel pipe according to the profile of the stainless steel pipe;

[0029] S234: Pick up the two lowest points of the fracture groove on the profile of the stainless steel pipe, and measure the distance between the two lowest points and the profile line of the end surface of the stainless steel pipe, respectively, which is the processing depth value of the fracture groove;

[0030] S235: Rotate the stainless steel pipe by 90° around the inner cavity axis of the stainless steel pipe as the rotation axis;

[0031] S236: Obtain the distance between the other two lowest points and the end face profile line of the stainless steel pipe in sequence according to steps S232, S233 and S234;

[0032] S237: Calculate the average value of the distance between the above-mentioned four lowest points and the end face profile line of the stainless steel pipe, and the average value is the breaking groove machining depth value.

[0033] Further, the S25 comprises:

[0034] S251: Align the stainless steel pipe with the breaking groove;

[0035] S252: Obtain the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument;

[0036] S253: Pick up two lowest points of the breaking groove on the profile of the stainless steel pipe, measure the included angle between the two breaking groove profile lines passing through the same lowest point respectively, and obtain two included angle values;

[0037] S254: Take the central axis of the inner cavity of the stainless steel pipe as the rotation axis, and rotate the stainless steel pipe by 90° around the rotation axis;

[0038] S255: Obtain the included angle between the other two breaking groove profile lines passing through the same lowest point in sequence according to steps S252 and S253;

[0039] S256: Calculate the average value of the included angle between the above-mentioned four breaking groove profile lines passing through the same lowest point, and the average value is the breaking groove bevel angle value.

[0040] Further, it further comprises step 3: detecting whether the center line of the breaking groove of the stainless steel pipe coincides with the central axis of the inner cavity of the stainless steel pipe by using the image measuring instrument.

[0041] Further, the step 3 comprises:

[0042] S31: Align the stainless steel pipe with the breaking groove;

[0043] S32: Obtain the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument;

[0044] S33: Pick up two lowest points of the breaking groove on the profile of the stainless steel pipe, connect the two lowest points, measure the included angle between the connecting line of the two lowest points and the central axis of the inner cavity of the stainless steel pipe, and compare the included angle with 90° to obtain the absolute value of the difference value;

[0045] S34: Take the central axis of the inner cavity of the stainless steel pipe as the rotation axis, and rotate the stainless steel pipe by 90° around the rotation axis;

[0046] S35: the angle between the line connecting the two lowest points and the central axis of the inner cavity of the stainless steel pipe is obtained in sequence according to steps S32, S33 and S34, and the angle is compared with 90° to obtain the absolute value of the difference;

[0047] S36: whether the average value of the two absolute values of the difference is within ±0.05° is calculated, and if yes, the center line of the breaking groove of the stainless steel pipe coincides with the central axis of the inner cavity of the stainless steel pipe.

[0048] Further, in step 1, the electrical parameters satisfy:

[0049] The pulse width is 30-60us, the pulse interval is 20-30us, the average machining current is 0.8-2A, and the average machining voltage is 30-60V.

[0050] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0051] 1. The present application performs electrical discharge machining by eccentric movement of the discharge end of the tool electrode on the stainless steel pipe, realizes the machining of the breaking groove of the ultra-thin long stainless steel pipe, overcomes the difficulty of high-precision machining of the breaking groove on the ultra-thin long thin-walled pipe, and after the machining is completed, the image measuring instrument is used to obtain the profile of the stainless steel pipe slice to measure the average value of the original wall thickness of the stainless steel pipe, and the image measuring instrument is used to obtain the profile of the stainless steel pipe with the breaking groove to obtain the average value of the breaking groove machining depth, so that the original wall thickness is reduced by the breaking groove machining depth to obtain the breaking groove wall thickness, which overcomes the problem of difficult measurement of the breaking groove wall thickness of the ultra-thin long stainless steel pipe, and reduces the influence of the non-uniform shape of the inner cavity of the stainless steel pipe on the precision of the breaking groove wall thickness detection.

[0052] 2. After the machining is completed, the image detector is used to obtain the profile of the stainless steel pipe with the breaking groove, the two lowest points of the breaking groove are picked up on the profile of the stainless steel pipe, the two lowest points are connected, the angle between the line connecting the two lowest points and the central axis of the inner cavity of the stainless steel pipe is measured, and whether the breaking groove center line coincides with the central axis of the inner cavity of the stainless steel pipe is determined by detecting whether the angle is a right angle, so that the machining precision of the breaking groove of the ultra-thin long stainless steel pipe is realized.

[0053] 3. The present application discards the traditional turning machining method of the ultra-thin 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-thin long stainless steel pipe to perform breaking groove machining, that is, the tool electrode does not contact the surface of the ultra-thin long stainless steel pipe during machining, and does not cause deformation of the ultra-thin long stainless steel pipe, which overcomes the problem of damage of the cutting force to the ultra-thin long stainless steel pipe.

[0054] 4、The tool electrode of the present application is eccentrically moved around the inner cavity central axis of the super-long stainless steel pipe with the discharge end of the tool electrode, so as to process the breaking groove of the super-long stainless steel pipe, i.e. the super-long stainless steel pipe does not need to rotate during the processing, and the annular breaking groove can be processed on the outer surface of the super-long stainless steel pipe, so as to overcome the problem that the coaxiality of the super-long stainless steel pipe is poor during the rotation, and the processing precision is affected.

[0055] 5、The discharge end of the tool electrode of the present application is in the shape of a ring, and is eccentrically moved on the outer end surface of the super-long stainless steel pipe, and during the process, the distance between the end surface of the discharge end and the end surface to be processed of the super-long stainless steel pipe is constantly changed, the working end is close to the super-long stainless steel pipe, and the non-working end is far away from the super-long stainless steel pipe, so as to process the outer end surface of the super-long stainless steel pipe through the working end; i.e. along the processing direction, the position of the working end on the inner circular end surface of the discharge end is constantly changed, i.e. when the inner circular end surface of the discharge end is close to the outer end surface of the super-long stainless steel pipe, 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 super-long stainless steel pipe, the end surface is changed into the non-working end, so as to realize the dynamic change between the working end and the non-working end, to avoid the working end of the tool electrode in the continuous processing state, greatly reduce the loss of the working end of the tool electrode, realize the tool electrode loss≤1%, and further reduce the deformation of the working end surface of the tool electrode, so as to improve the processing precision of the breaking groove of the super-long stainless steel pipe.

[0056] 6、The tool electrode of the present application is eccentrically moved around the inner cavity central axis of the super-long stainless steel pipe for one cycle, so as to complete the processing of the breaking groove of the super-long stainless steel pipe, realize one-time processing, and the processing efficiency is significantly improved.

[0057] 7、Through the eccentric movement of the tool electrode around the inner cavity central axis of the stainless steel pipe, the single-sided feed amount of each end surface of the discharge end is the same, so as to ensure the consistency of the breaking groove processing depth, and improve the processing precision of the breaking groove.

[0058] 8、The breaking groove with different wall thicknesses can be processed by adjusting the value of the single-sided feed amount, and the breaking groove with different inclined angles α can be processed by adjusting the shape of the discharge end of the tool electrode, which lays a foundation for rapid production and batch production of products.

[0059] 9、The discharge end sleeve of the tool electrode of the present application makes eccentric motion on the ultra-fine long stainless steel pipe, when 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, in the process of changing 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 the working fluid, in the process of changing 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 metal scraps, thereby avoiding the accumulation of metal scraps at the discharge end due to the delay in discharging the metal scraps, thereby 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.

[0060] 10、The discharge end sleeve of the tool electrode of the present application makes eccentric motion on the ultra-fine long stainless steel pipe, which can efficiently discharge metal scraps, and thus can realize electric spark machining with a smaller machining gap, thereby reducing the machining current and machining voltage value, reducing the machining cost, and obtaining a fracture groove with low surface roughness.

[0061] In the present application, the above technical solutions 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 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

[0062] 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, illustrate embodiments of the present application and together with the description serve to explain the principles of the present application.

[0063] Figure 1 Flow chart of the production method of the ultra-fine long stainless steel pipe with a fracture groove of the present application;

[0064] Figure 2 Structure schematic diagram of the tool electrode of the present application;

[0065] Figure 3 Structure schematic diagram of the tool electrode of the present application; Figure 2 Cross-sectional schematic diagram at A-A in the present application;

[0066] Figure 4 Structure schematic diagram 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;

[0067] Figure 5 Structure schematic diagram 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;

[0068] Figure 6The cross-sectional view of the discharge end of the tool electrode of the present application on the stainless steel pipe;

[0069] Figure 7 The schematic diagram of the movement track of the center point O2 of the discharge end of the tool electrode of the present application when the discharge end moves eccentrically around the central axis of the inner cavity of the stainless steel pipe;

[0070] Figure 8 The schematic diagram of the movement track of any point O3 of the discharge end of the tool electrode of the present application when the discharge end moves eccentrically around the central axis of the inner cavity of the stainless steel pipe;

[0071] Figure 9 The schematic diagram of the structure of the stainless steel pipe with the breaking groove of the present application;

[0072] Figure 10 The schematic diagram of the structure of the stainless steel pipe with the breaking groove of the present application; Figure 9 The enlarged schematic diagram of the structure at B in the middle;

[0073] Figure 11 The schematic diagram of the cross-sectional structure of the stainless steel pipe with the breaking groove of the present application;

[0074] Figure 12 The schematic diagram of the cooperation structure of the bearing assembly of the present application and the stainless steel pipe;

[0075] Figure 13 The schematic diagram of the actual object of the breaking groove of the stainless steel pipe of the present application after processing;

[0076] Figure 14 The schematic diagram of the structure of the stainless steel pipe with the breaking groove obtained by the image measuring instrument of the present application;

[0077] Figure 15 The schematic diagram of the cross-sectional structure of the stainless steel pipe slice obtained by the image measuring instrument of the present application.

[0078] Reference signs:

[0079] 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 - central axis of the inner cavity of the stainless steel pipe; 11 - connecting line between the two lowest points of the breaking groove profile; 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- the 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 tube; S2 - the machining gap; O1 - the center point of the discharge end; O2 - the center point of the inner cavity of the stainless steel tube; O3 - the point selected on the discharge end; d - the processing depth of the breaking groove. DETAILED DESCRIPTION

[0080] 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 intended to convey principles of the present application, and are not intended to limit its scope.

[0081] Generally, the ratio of diameter to length reaches 1:100-150, which belongs to super thin long shaft. For example, the stainless steel tube used in some aviation products has an outer diameter of 2 mm, an inner diameter of 1 mm, and a length of 1-1.2 m. The ratio of the outer diameter to the length of the stainless steel tube is 1:500-600, which belongs to super thin long stainless steel tube. During processing, a breaking groove is generally needed to be processed on the super thin long steel tube. 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.

[0082] Due to the small diameter and thin wall thickness of the super thin stainless steel tube, and the even thinner wall thickness at the position of the breaking groove, for example, the wall thickness at the position of the breaking groove is 0.3±0.05 mm, which cannot be obtained by direct measurement. When the breaking groove is processed at a certain position of the super thin long stainless steel tube, it is difficult to ensure the wall thickness at the position of the breaking groove by using the traditional turning processing method. This is because the longer the length, the greater the centrifugal force caused by the rotation of the workpiece, and the worse the coaxiality of the workpiece. In addition, the cutting force generated is easy to cause deformation of the super thin long stainless steel tube.

[0083] In addition, due to the small diameter and thin wall thickness of the super thin long stainless steel tube, it is difficult to control the uniformity of the shape and size of the inner wall of the stainless steel tube during the production of the super thin long stainless steel tube, so that the original wall thickness of the super thin long stainless steel tube is not uniform. When detecting the wall thickness of the breaking groove of the stainless steel tube, it is generally difficult to achieve high-precision measurement by using the existing measuring tools, so that the production quality of the super thin long stainless steel tube with the breaking groove cannot be guaranteed.

[0084] To solve the above problems, the present application provides a production method of super thin long stainless steel tube with a breaking groove, which comprises the following steps:

[0085] Step 1: the discharge end of the tool electrode 1 is sleeved on the stainless steel tube 6 and makes eccentric motion around the inner cavity central axis of the stainless steel tube to perform electric spark machining on the breaking groove 601 of the stainless steel tube.

[0086] Step 2: the wall thickness of the breaking groove 601 of the stainless steel tube is detected and obtained by using an image measuring instrument, and compared with the standard value.

[0087] In step 1, the discharge end 101 of the tool electrode 1 includes a plurality of electric spark machining points circumferentially arranged around the stainless steel tube, which can be circumferentially continuous or discontinuous around the stainless steel tube 6, and can realize continuous machining of the breaking groove on the surface to be machined. During machining, the same electric spark machining point includes a working state and a non-working state. By changing the distance between the electric spark machining point and the surface to be machined, the same electric spark machining point is in a working state or a non-working state. The working state of the plurality of electric spark machining points circumferentially arranged around the stainless steel tube 6 realizes the machining of the breaking groove 601 on the surface to be machined.

[0088] When the distance between the electric spark machining point and the surface to be machined is greater than the 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 above-mentioned threshold value is the discharge distance between the electric spark machining point and the surface to be machined that meets the machining requirements.

[0089] In a possible implementation, one end of the tool electrode 1 is a circular ring, that is, the plurality of electric spark machining points circumferentially arranged around the stainless steel tube form a continuous circular ring, as shown in FIG. 1B, the inner circle end of the circular ring matches the shape of the breaking groove 601, that is, the inner circle 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. Figures 2-6 The other end of the tool electrode 1 is a conductive end 104, which is electrically connected to an output end of a power supply device arranged on the machine tool, for introducing current and transmitting current to the inner circle end. At this time, the inner circle 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 points circumferentially arranged around the stainless steel tube of the discharge end 101.

[0090] 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 inner cavity central axis 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 machined end surface of the stainless steel pipe 6 is constantly changing; when the distance between the electric spark machining point and the machined surface 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 machined surface 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 machined surface, 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 inner cavity central axis of the stainless steel pipe for one cycle, 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 not in a continuous machining state, thereby reducing the wear of the tool electrode 1.

[0091] 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 inner cavity central axis of the stainless steel pipe 6 for machining.

[0092] After the tool electrode 1 moves eccentrically for one cycle, all the end surfaces of the discharge end 101 participate in electric spark machining, that is, all the working ends 102 form a complete discharge end 101, and the machining tracks of all the working ends 102 together form the breaking groove 601 of the ultra-fine long stainless steel pipe; along the machining direction 7, the working ends 102 exhibit a "circular motion" phenomenon on the discharge end 101, that is, the positions of the working ends 102 are different at different times, so that all the working ends 102 are alternately and orderly machined, the machining direction 7 is the circumferential direction around the outer end surface of the stainless steel pipe 6, and the plane where the circumferential direction is located is perpendicular to the inner cavity central axis of the stainless steel pipe 6.

[0093] Compared with the prior art, 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 stainless steel pipe 6, and in this process, the distance between the end surface of the discharge end 101 and the end surface to be machined of the stainless steel pipe 6 is constantly changing, the distance being closer is the working end 102, and the distance being farther is the non-working end 103, and the outer end surface of the stainless steel pipe 6 is electric spark machined through the working end 102, and along the machining direction, the position of the working end 102 is constantly changing within 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 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 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, thereby avoiding the working end 102 of the tool electrode 1 in the continuous machining state, greatly reducing the wear of the working end of the tool electrode 1, realizing the tool electrode wear ≤1%, and further reducing the deformation of the working end surface of the tool electrode 1, thereby improving the machining precision of the fracture groove 601 of the super-thin long stainless steel pipe. In addition, after the machining is completed, the profile of the stainless steel pipe section is obtained by using an image measuring instrument to measure the average value of the original wall thickness of the stainless steel pipe 6, and the profile of the stainless steel pipe with the fracture groove is obtained by using the image measuring instrument to obtain the average value of the fracture groove machining depth, so that the fracture groove wall thickness is obtained by subtracting the fracture groove machining depth from the original wall thickness, thereby overcoming the problem of difficult measurement of the fracture groove wall thickness of the super-thin long stainless steel pipe, and reducing the influence of the non-uniform shape of the inner cavity of the stainless steel pipe on the precision of the fracture groove wall thickness detection.

[0094] 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 machining 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.

[0095] Specifically, in step 1, the tool electrode 1 is installed on the machine tool, and when machining, the machine tool drives the tool electrode 1 to make eccentric motion, so that the discharge end 101 of the tool electrode 1 performs electric spark machining around the end surface of the stainless steel pipe 6, 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 in the inner cavity of the stainless steel pipe 6.

[0096] 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.

[0097] wherein the single-sided feed amount O1O2 satisfies:

[0098] O1O2=S1+(H1-H2)-S2

[0099] wherein O1 represents the center point of the discharge end 101 of the tool electrode 1;

[0100] O2 represents the center point of the inner cavity of the stainless steel pipe 6;

[0101] H1 is the wall thickness of the stainless steel pipe 6;

[0102] H2 is the wall thickness of the fracture groove 601;

[0103] S1 is the clearance gap between the discharge end 101 and the outer end surface of the stainless steel pipe 6;

[0104] 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.

[0105] wherein S1 satisfies:

[0106]

[0107] wherein, as shown in Figure 4 , S 11 , S 12 , S 13 , S 14 are the 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.

[0108] 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.

[0109] wherein the machining gap S2 is 10-50μm, which meets the requirements of electric spark machining.

[0110] Exemplary, S2 = 10 μm; H1 = 0.5 mm, H2 = 0.3 mm, S1 = 2.058 mm, at this time, O1O2 = 2.248 mm.

[0111] Wherein, S can be measured by the automatic centering module on the machine tool 11 , S 12 , S 13 , S 14 , wherein, if the four values are equal, i.e. 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 tube 6.

[0112] Wherein, after adjusting the tool electrode 1 to coincide 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 is, and the more accurate the unilateral feed amount O1O2 is, so that the machining gap accuracy can be ensured during the eccentric movement 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.

[0113] Specifically, after adjusting the tool electrode 1 to coincide with the central axis of the inner cavity of the stainless steel tube 6, the tool electrode 1 is driven by the machine tool to move eccentrically, and the detailed process is as follows.

[0114] 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 tube 6 is described as follows:

[0115] 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;

[0116] O1 is rotated around O2 with O1O2 as the radius, at this time, the trajectory of O1 is a circle, as shown in Figure 7 , the center of the circle is O2, and the radius is O1O2;

[0117] 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 tube 6 reaches 10 μm, the power supply device is started to deliver pulse voltage to the tool electrode 1 and the stainless steel tube 6, and the surface metal of the stainless steel tube 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.

[0118] In order to further illustrate the movement track of the tool electrode 1, an arbitrary point O3 on the discharge end 101 is selected, and the track of O3 is described as follows:

[0119] The tool electrode 1 is moved so that O3 moves towards O2 by a distance of O1O2;

[0120] When O1 rotates around O2, at this time, as shown in Figure 8 , the track of O3 is a circle with the initial position of O3 as the center and O1O2 as the radius;

[0121] In the process of movement of O3, 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 movement distance of O3 reaches O1O2, and then O3 makes a circular movement with its initial position as the center.

[0122] In this way, in the process of 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 changed, 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 is realized from close to far, and then the discharge end 101 is changed 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.

[0123] In the process of 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 changed, 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 is realized from close to far, and then the discharge end 101 is changed 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.

[0124] In the process of 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 changed, 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 is realized from close to far, and then the discharge end 101 is changed 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.

[0125] 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, and the medium is exemplarily 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 at the nearest point between the discharge end 101 and the stainless steel pipe 6 under the current condition is broken down to form a discharge channel, and because the cross-sectional area of the channel is very small, the discharge time is extremely short, so that the energy is highly concentrated (10 6 W / cm2 ), 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.

[0126] For example, during the machining process, the electrical parameters satisfy:

[0127] 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.

[0128] Specifically, during machining, the tool electrode 1 is eccentrically moved by the machine tool, and the stainless steel pipe 6 remains stationary.

[0129] Specifically, during machining, the tool electrode 1 is eccentrically moved by the machine tool, and the stainless steel pipe 6 remains stationary.

[0130] 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, 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.

[0131] For example, during the machining process, the non-electrical parameters satisfy:

[0132] 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.

[0133] Specifically, the stainless steel pipe 6 is clamped by the bearing assembly to ensure the machining precision.

[0134] Specifically, the stainless steel pipe 6 is clamped by the bearing assembly to ensure the machining precision. Figures 11-12As shown, the bearing assembly includes the isometric positioning block 3 and the auxiliary bearing block 4 installed on the machine tool; the stainless steel pipe 6 is placed on the isometric positioning block 3 and the auxiliary bearing block 4 to clamp the stainless steel pipe 6.

[0135] Specifically, two isometric positioning blocks 3 are provided, and the two isometric positioning blocks 3 are respectively located on both sides of the to-be-processed position of the stainless steel pipe 6, so as to ensure the stability of the to-be-processed position of the stainless steel pipe 6 during processing.

[0136] Specifically, two auxiliary bearing blocks 4 are provided, and the two isometric positioning blocks 3 are located between the two auxiliary bearing blocks 4, so as to support and position the two ends of the stainless steel pipe 6 through the two auxiliary bearing blocks 4, and further ensure the stability of the stainless steel pipe 6 during processing.

[0137] Wherein, the upper end faces of the isometric positioning block 3 and the auxiliary bearing block 4 are flush, and the upper end faces of the isometric 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.

[0138] Further, the clamping plate 5 is also provided on the isometric positioning block 3, the clamping plate 5 covers the V-shaped groove and is clamped on the isometric 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 60°-90°, and the depth is 5-10mm.

[0139] Wherein, before placing the stainless steel pipe 6 on the isometric positioning block 3, first, the tool electrode 1 needs to be 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 isometric positioning block 3, the auxiliary bearing block 4 and the clamping plate 5, and the stainless steel pipe 6 is aligned by the isometric positioning block 3 and the auxiliary bearing block 4.

[0140] Specifically, after the tool electrode 1 is aligned, the positions of the isometric 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.

[0141] Wherein, the alignment process of the stainless steel pipe 6 is as follows.

[0142] First, first fix the two isometric positioning blocks 3 and the two auxiliary bearing 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.

[0143] 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.

[0144] Wherein, one end of the transmission rod 2 is connected with the tool electrode 1, and is 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, 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 central axis of the inner cavity of the stainless steel pipe 6.

[0145] In this way, one cycle of 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 can complete the machining of the breaking groove 601 of the stainless steel pipe, realize one-time machining, and significantly improve the machining efficiency.

[0146] Specifically, after the machining is completed, the machined breaking groove is detected by the method of step 2, and the step 2 includes:

[0147] S21: obtaining a stainless steel pipe sample slice without a breaking groove;

[0148] S22: detecting and obtaining the wall thickness value of the stainless steel pipe sample slice by using an image measuring instrument;

[0149] S23: detecting and obtaining the machining depth value of the stainless steel pipe breaking groove by using an image measuring instrument;

[0150] S24: obtaining the difference value between the wall thickness value of the stainless steel pipe sample slice and the machining depth value of the stainless steel pipe breaking groove, and comparing the difference value with a standard value of the wall thickness of the breaking groove;

[0151] Step 2 further includes:

[0152] S25: obtaining the bevel angle value of the stainless steel pipe breaking groove by using an image measuring instrument, and comparing the bevel angle value with a standard value.

[0153] Wherein, S21 includes:

[0154] S211: aligning the stainless steel pipe with the breaking groove;

[0155] The stainless steel pipe with the breaking groove is aligned by using the above bearing assembly, so that the central axis of the inner cavity of the stainless steel pipe is perpendicular to the cutting surface of the stainless steel pipe sample slice, and the use of the stainless steel pipe with the breaking groove is avoided.

[0156] S212: cutting a 1mm stainless steel pipe sample slice at the end of the stainless steel pipe;

[0157] Wherein, the wall thickness of the stainless steel pipe is replaced by the wall thickness of the cut section, on the one hand, it is convenient for detection, on the other hand, it avoids the deformation of the end of the stainless steel pipe in the process of production and transportation, which affects the accuracy of the wall thickness detection; in addition, the size of the cut section of the stainless steel pipe is small, which avoids affecting the use of the stainless steel pipe with the breaking groove.

[0158] Wherein, S22 comprises:

[0159] S221: cleaning the cut section of the stainless steel pipe to avoid the influence of the debris adhered to the cutting surface on the accuracy of the cutting surface profile obtained by the image measuring instrument.

[0160] S222: obtaining the cutting surface profile of the cut section of the stainless steel pipe by using the image measuring instrument;

[0161] S223: selecting four points on the cutting surface profile to obtain the wall thickness values of the cut section of the stainless steel pipe at the four points;

[0162] Wherein, the four selected points are uniformly distributed on the cutting surface profile of the cut section of the stainless steel pipe; for example, two mutually perpendicular diameters of the cutting surface are selected at random, and the intersection points of the two mutually perpendicular diameters and the end of the cutting surface are the four selected points.

[0163] S224: calculating the average value of the wall thickness values of the cut section of the stainless steel pipe at the four points, and taking the average value as the original wall thickness value of the stainless steel pipe, so as to reduce the influence of the uneven inner cavity of the stainless steel pipe on the wall thickness detection accuracy of the breaking groove.

[0164] Wherein, S23 comprises:

[0165] S231: aligning the stainless steel pipe with the breaking groove;

[0166] Wherein, the stainless steel pipe with the breaking groove is aligned by using the above-mentioned bearing assembly.

[0167] S232: obtaining the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument;

[0168] S233: measuring the outer diameter value of the stainless steel pipe according to the profile of the stainless steel pipe;

[0169] S234: picking up two lowest points of the breaking groove on the profile of the stainless steel pipe, and measuring the distances between the two lowest points and the profile line of the end surface of the stainless steel pipe, which are the processing depth values of the breaking groove;

[0170] S235: rotating the stainless steel pipe by 90° around the rotation axis of the inner cavity of the stainless steel pipe;

[0171] S236: sequentially obtaining the distances between the other two lowest points and the profile line of the end surface of the stainless steel pipe according to steps S232, S233 and S234.

[0172] S237: Calculate the average value of the distances between the above four lowest points and the profile line of the end face of the stainless steel pipe, and the average value is the fracture groove machining depth value. In this way, the influence of the uneven fracture groove machining depth on the fracture groove wall thickness detection accuracy is reduced.

[0173] In S24, the difference between the wall thickness value of the stainless steel pipe sample section and the machining depth value of the stainless steel pipe fracture groove is obtained, and the difference is compared with the fracture groove wall thickness standard value; if the error is within ±0.05mm, the stainless steel pipe fracture groove machining precision meets the requirements.

[0174] S25 includes:

[0175] S251: Align the stainless steel pipe with the fracture groove;

[0176] The above bearing assembly is used to align the stainless steel pipe with the fracture groove.

[0177] S252: Obtain the profile of the stainless steel pipe with the fracture groove using an image measuring instrument;

[0178] S253: Pick up two lowest points of the fracture groove on the profile of the stainless steel pipe, respectively measure the included angle between the two fracture groove profile lines passing through the same lowest point, and obtain two included angle values;

[0179] S254: Rotate the stainless steel pipe by 90° around the rotation axis of the inner cavity axis of the stainless steel pipe;

[0180] S255: Obtain the included angle between the other two fracture groove profile lines passing through the same lowest point in sequence according to steps S252 and S253;

[0181] S256: Calculate the average value of the above four included angles between the two fracture groove profile lines passing through the same lowest point, and the average value is the fracture groove bevel angle value. In this way, the influence of the uneven fracture groove machining on the fracture groove bevel angle detection accuracy is reduced.

[0182] The above production method further includes step 3, that is, detecting whether the center line of the fracture groove of the stainless steel pipe coincides with the inner cavity axis of the stainless steel pipe, and the step 3 includes:

[0183] S31: Align the stainless steel pipe with the fracture groove;

[0184] The above bearing assembly is used to align the stainless steel pipe with the fracture groove.

[0185] S32: Obtain the profile of the stainless steel pipe with the fracture groove using an image measuring instrument;

[0186] S33: picking up two lowest points of the breakage groove on the profile of the stainless steel pipe, connecting the two lowest points, measuring the included angle between the connecting line of the two lowest points and the central axis in the inner cavity of the stainless steel pipe, and comparing the included angle with 90° to obtain the absolute value of the difference;

[0187] S34: rotating the stainless steel pipe by 90° around the central axis in the inner cavity of the stainless steel pipe.

[0188] S35: sequentially obtaining the included angle between the connecting line of the two outer lowest points and the central axis in the inner cavity of the stainless steel pipe according to steps S32, S33 and S34, and comparing the included angle with 90° to obtain the absolute value of the difference.

[0189] S36: calculating whether the average value of the above two absolute values of the difference is within ±0.05°, and if so, the center line of the breakage groove of the stainless steel pipe coincides with the central axis in the inner cavity of the stainless steel pipe.

[0190] In this way, by detecting whether the center line of the breakage groove of the stainless steel pipe coincides with the central axis in the inner cavity of the stainless steel pipe, it is ensured that the plane where the circular ring formed by the lowest end of the breakage groove is perpendicular to the central axis in the inner cavity of the stainless steel pipe, and further ensures that when the product reaches the predetermined height and position, the flight product guidance system can be separated from the product fairing body to meet the production requirements.

[0191] In order to better utilize the above processing method to process the breakage groove 601 of the stainless steel pipe, the application further provides a processing device, which comprises a tool electrode 1 mounted on a machine tool, a bearing assembly for clamping the stainless steel pipe 6, and a driving assembly for controlling the movement state of the tool electrode 1.

[0192] The one end of the tool electrode 1 is a discharge end 101, and the discharge end 101 comprises a plurality of electric spark machining points arranged circumferentially around the stainless steel pipe 6. The same electric spark machining point comprises a working state and a non-working state.

[0193] When the distance between the electric spark machining point and the surface to be processed 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 processed is less than or equal to the threshold value, the electric spark machining point is in a working state. The above-mentioned threshold value is the discharge distance between the electric spark machining point and the surface to be processed that meets the processing requirements. Exemplarily, the distance is 0-50 μm.

[0194] The working state of the plurality of electric spark machining points arranged circumferentially around the stainless steel pipe 6 realizes the processing of the breakage groove 601 on the surface to be processed.

[0195] It can be understood that the discharge end 101 includes a plurality of electric spark machining points circumferentially arranged around the stainless steel pipe, which can be continuously and uninterruptedly distributed circumferentially around the stainless steel pipe, or discontinuously distributed circumferentially around the stainless steel pipe, and can realize continuous machining and forming of the breaking groove on the surface to be machined.

[0196] In a possible implementation, one end of the tool electrode 1 is in the shape of a circular ring, that is, the plurality of electric spark machining points circumferentially arranged around the stainless steel pipe form a continuous circular ring, 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 in the shape of a protrusion, and the breaking groove 601 is in the shape of a groove, and 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 an electrically conductive end 104, which is electrically connected to an output end of a power supply device arranged on a machine tool, and is used to introduce electric current and transmit the electric 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 electric spark machining points circumferentially arranged around the stainless steel pipe of the discharge end 101 is used to realize machining of the breaking groove on the surface to be machined.

[0197] In a possible implementation, the discharge end is in 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 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 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 machined end surface 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; in this way, the same electric spark machining point realizes the transition between the working state and the non-working state, and the working states of all the electric spark machining points collectively 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 pipe for one revolution, and all the working ends circumferentially form a continuous circular ring-shaped discharge end around the stainless steel pipe, thereby avoiding the discharge end 101 of the tool electrode 1 in a continuous machining state, and further reducing the loss of the tool electrode 1.

[0198] 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 during the eccentric movement of the discharge end around the central axis of the inner cavity of the stainless steel pipe 6; and the machining tracks of the plurality of working ends collectively constitute the breaking groove of the stainless steel pipe 6.

[0199] 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 together constitute the fracture groove 601 of the ultra-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 realize alternate and orderly machining, and 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.

[0200] 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 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 in the inner cavity 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, 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 10-20 mm, which is 5-10 times the outer diameter of the stainless steel pipe 6. In this way, the values of the single-sided feed amounts 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 in the inner cavity of the stainless steel pipe 6.

[0201] Wherein, the single-sided feed amount O1O2 satisfies:

[0202] O1O2=S1+(H1-H2)-S2

[0203] Wherein, O1 represents the center point of the discharge end 101 of the tool electrode;

[0204] O2 represents the center point of the inner cavity of the stainless steel pipe 6;

[0205] H1 is the wall thickness of the stainless steel pipe 6;

[0206] H2 is the wall thickness of the fracture groove 601;

[0207] S2 is the machining gap, that is, the closest distance between the working end 102 and the end face of the stainless steel pipe 601 when the tool electrode 1 is in eccentric motion;

[0208] S1 is the clearance gap between the discharge end 101 and the outer end face of the stainless steel pipe 6.

[0209] Wherein, S1 satisfies:

[0210]

[0211] Wherein, S 11 , S12 13 14 S is the actual excess gap value between the 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.

[0212] S is 2.055 mm, 2.060 mm, 2.065 mm, and 2.050 mm, respectively, and S1 is 2.058 mm. 11 12 13 14 S is 2.055 mm, 2.060 mm, 2.065 mm, and 2.050 mm, respectively, and S1 is 2.058 mm.

[0213] The machining gap S2 is 10-50 μm to meet the requirements of electric spark machining.

[0214] S2 is 10 μm, H1 is 0.5 mm, H2 is 0.3 mm, and S1 is 2.058 mm, and O1O2 is 2.248 mm.

[0215] The automatic centering module on the machine tool can be used to measure S 11 12 13 14 If the four values are equal, the center of the inner circular end of the discharge end 101 of the tool electrode 1 coincides with the central axis of the inner cavity of the stainless steel pipe 6.

[0216] 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 12 13 14 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. Thus, during the eccentric motion of the tool electrode 1, the machining gap accuracy can be ensured, and the machining depth of the working end 101 is ensured to ensure the size accuracy of the broken groove 601.

[0217] 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, and the detailed process is as follows.

[0218] 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:

[0219] The tool electrode 1 is moved so that O1 is away from O2 by the same distance as the unilateral feed amount O1O2, and the distance between O1 and O2 is O1O2 at this time.​​​​​​​​​​​

[0220] O1 rotates around O2, at this time, the trajectory of O1 is a circle, the center of the circle is O2, and the radius of the circle is O1O2;

[0221] 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 circular motion around O2.

[0222] In order to further illustrate the 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:

[0223] The tool electrode 1 is moved so that O3 moves towards O2 by a distance of O1O2;

[0224] 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 circular motion around O2.

[0225] 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 circular motion around O2.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] Exemplarily, in the process of machining, the electrical parameters satisfy:

[0230] 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.

[0231] 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.

[0232] 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.

[0233] Exemplarily, in the process of machining, the non-electrical parameters satisfy:

[0234] 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.

[0235] 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.

[0236] Specifically, two equal-height positioning blocks 3 are arranged, 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. Exemplarily, the distance between the two equal-height positioning blocks 3 is 30mm.

[0237] 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.

[0238] The upper end faces of the equal-height positioning blocks 3 and the auxiliary bearing blocks 4 are flush, and V-shaped grooves are formed in the upper end faces of the equal-height positioning blocks 3 and the auxiliary bearing blocks 4, and the stainless steel pipe 6 is placed in the V-shaped grooves to limit the stainless steel pipe 6.

[0239] Further, the clamping plates 5 are arranged on the equal-height positioning blocks 3, 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.

[0240] 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, the auxiliary bearing blocks 4 and the clamping plates 5, and the stainless steel pipe 6 is aligned by the equal-height positioning blocks 3 and the auxiliary bearing blocks 4.

[0241] Specifically, after the tool electrode 1 is aligned, the positions of the equal-height positioning blocks 3 and the auxiliary bearing blocks 4 on the machine tool are adjusted by 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 O1O2 and further improve the machining precision.

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

[0243] 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 ≤0.01 mm.

[0244] 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, and the other end of the transmission rod 2 is installed on the machine tool during machining, so that the machine tool drives the transmission rod 2 to swing, and then the tool electrode 1 is driven to move by the transmission rod 2, so that the discharge end 101 of the tool electrode 1 performs eccentric motion around the inner cavity center axis of the stainless steel pipe 6.

[0245] In this way, the discharge end 101 of the tool electrode 1 performs eccentric motion around the inner cavity center axis of the stainless steel pipe 6 for one revolution, and the machining of the stainless steel pipe breaking groove 601 is completed, which realizes one-time machining and significantly improves the machining efficiency.

[0246] Compared with the prior art, the discharge end 101 of the tool electrode 1 is sleeved on the stainless steel pipe 6 for eccentric movement to perform electric spark machining, the machining of the ultra-slim long stainless steel pipe breaking groove 601 is realized, the difficulty of machining the breaking groove with high precision on the ultra-slim long thin-walled pipe is overcome, after the machining is completed, the profile of the stainless steel pipe section is obtained by using the image measuring instrument, the average value of the original wall thickness of the stainless steel pipe is measured, the profile of the stainless steel pipe with the breaking groove is obtained by using the image measuring instrument, the average value of the machining depth of the breaking groove is obtained, the original wall thickness is subtracted from the machining depth of the breaking groove to obtain the breaking groove wall thickness, the problem that it is difficult to measure the breaking groove wall thickness of the ultra-slim long stainless steel pipe is overcome, and meanwhile, the influence of the non-uniformity of the inner cavity shape of the stainless steel pipe on the precision of the breaking groove wall thickness detection is reduced.

[0247] After the machining is completed, the profile of the stainless steel pipe with the breaking groove is obtained by using the image measuring instrument, two lowest points of the breaking groove are picked up on the stainless steel pipe profile, the two lowest points are connected, the included angle between the connecting line of the two lowest points and the central axis of the inner cavity of the stainless steel pipe is measured, whether the central line of the breaking groove coincides with the central axis of the inner cavity of the stainless steel pipe can be determined by detecting whether the included angle is a right angle, and the machining precision of the breaking groove of the ultra-slim long stainless steel pipe is realized.

[0248] The working end 102 of the tool electrode 1 is used for electric discharge etching of the surface metal of the ultra-slim long stainless steel pipe 6 to perform the breaking groove 601 machining, that is, in the machining process, the tool electrode 1 does not contact the surface of the ultra-slim long stainless steel pipe, and the deformation of the ultra-slim long stainless steel pipe is avoided, and the problem of damage of the cutting force to the ultra-slim long stainless steel pipe is overcome.

[0249] The discharge end 101 of the tool electrode 1 is used for eccentric movement around the central axis of the inner cavity of the ultra-slim long stainless steel pipe to perform the breaking groove 601 machining, that is, in the machining process, the ultra-slim long stainless steel pipe does not need to be moved, and the annular breaking groove 601 on the outer surface of the ultra-slim long stainless steel pipe can be machined, and the problem of poor coaxiality of the ultra-slim long stainless steel pipe in the rotation process affecting the machining precision is overcome.

[0250] In the machining process, the ultra-slim long stainless steel pipe 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 ultra-slim long stainless steel pipe is limited by the clamping plate 5, so that the clamping and positioning of the ultra-slim long stainless steel pipe are realized, the clamping is convenient, and the stability of the ultra-slim long stainless steel pipe 6 in the machining process can be ensured.

[0251] 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 ≤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.

[0252] The discharge end 101 of the tool electrode 1 of the application eccentrically moves around the inner cavity central axis of the super-long stainless steel pipe 6 for one cycle, that is, the machining of the breaking groove 601 of the super-long stainless steel pipe is completed, and the machining is in place once, so that the machining efficiency is significantly improved.

[0253] 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 is the same, which ensures the consistency of the machining depth of the breaking groove 601, so that the machining precision of the breaking groove 601 is improved.

[0254] The discharge end 101 of the tool electrode 1 is convex, and the breaking groove 601 is concave, that is, the cross-sectional size of the convex is the same as the cross-sectional shape of the concave, so that after the discharge end 101 of the tool electrode 1 eccentrically moves 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.

[0255] 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.

[0256] The discharge end 101 of the tool electrode 1 of the present application is eccentrically moved on the super-fine long stainless steel pipe 6, and 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, and 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 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.

[0257] By eccentrically moving 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 thus the electric spark machining can be performed with a smaller machining gap. In this way, the machining current and voltage value can be reduced, the machining cost can be reduced, and a broken groove 601 with a lower surface roughness can be obtained.

[0258] Embodiment 1

[0259] The production method of the super-fine long stainless steel pipe with a broken groove, as shown in Figure 1 includes the following steps:

[0260] Step 1: Adjust the position of the tool electrode 1 by using the machine tool, so that the plane where the discharge end 101 of the tool electrode 1 is located is perpendicular to the worktable surface 9 of the machine tool.

[0261] Specifically, the worktable surface 9 of the machine tool is a horizontal surface, and the tool electrode 1 is vertically installed on the machine tool and connected with a transmission rod installed on the machine tool.

[0262] Step 2: Clamping the stainless steel pipe 6 by using the bearing assembly, and aligning the stainless steel pipe 6.

[0263] Specifically, first, fix two pieces of equal-height positioning blocks 3 and two pieces of auxiliary support blocks 4 on the worktable 9, and use a dial indicator to align the side surface of the equal-height positioning blocks 3 and the auxiliary support blocks 4 with the X-axis of the machine tool, and adjust the position of the equal-height positioning blocks 3 and the auxiliary support blocks 4 by using the machine tool, wherein the parallelism error is ≤0.01mm.

[0264] Then, place the stainless steel pipe 6 on the equal-height positioning blocks 3, and before placing, pass the stainless steel pipe 6 through the inner circular end of the lower end of the tool electrode 1, and ensure that the stainless steel pipe 6 is in a horizontal position by using the equal-height positioning blocks 3, and the distance between the two equal-height positioning blocks 3 is 30mm.

[0265] Then, place the two ends of the stainless steel pipe 6 on the auxiliary support blocks 4, and finally fix them with the clamping plate 5.

[0266] Step 3: Adjust the center line of the discharge end 101 of the tool electrode 1 to coincide with the axis of the inner cavity of the stainless steel pipe 6 by using the machine tool;

[0267] Specifically, first, the machine tool moves the bearing assembly in the X-axis direction to adjust the position of the stainless steel pipe 6, so that the position to be machined of the stainless steel pipe 6 is located within the discharge end 101 of the tool electrode 1;

[0268] Then, the machine tool automatically measures the values of S 11 , S 12 , S 13 , and S 14 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 axis of the inner cavity of the stainless steel pipe 6, if not, the machine tool continues to adjust the position of the bearing assembly until the requirements are met.

[0269] Step 4: Use the tool electrode 1 to perform electric spark machining on the stainless steel pipe 6 in the working fluid of kerosene and water. Including:

[0270] S401: Control the eccentric motion of the discharge end 101 of the tool electrode 1 around the axis of the inner cavity of the stainless steel pipe 6;

[0271] Specifically, the machine tool drives the transmission rod 2 to swing in the swing plane YZ, and then controls the eccentric motion of the discharge end 101 of the tool electrode 1 around the axis of the inner cavity of the stainless steel pipe 6 through the transmission rod 2; the eccentric motion direction 8 is as shown in Figure 7 .

[0272] Wherein, the swing speed of the transmission rod 2 is 0.5 rpm;

[0273] 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, and S1=2.058 mm at this time;

[0274] The machining gap S2 is 10 μm;

[0275] The single-sided feed amount O1O2=S1+(H1-H2)-S2=2.058+(0.5-0.3)-0.01=2.248 mm;

[0276] The machining speed is 0.04 g / min.

[0277] S402: When the tool electrode 1 performs eccentric motion, power is supplied to the tool electrode 1 to perform electric spark machining.

[0278] Specifically, the electrical parameters satisfy:

[0279] The pulse width is 40 s, the pulse interval is 26 s, the average machining current is 1 A, and the average machining voltage is 40 V.

[0280] Step 5: The wall thickness and the bevel angle value of the stainless steel pipe fracture groove are detected by using an image measuring instrument, and compared with the standard value.

[0281] Specifically, the method comprises the steps of:

[0282] S51: obtaining a stainless steel pipe sample slice without a fracture groove;

[0283] S52: obtaining a wall thickness value of the stainless steel pipe sample slice by using an image measuring instrument;

[0284] S53: obtaining a machining depth value of the stainless steel pipe fracture groove by using an image measuring instrument;

[0285] S54: obtaining a difference value between the wall thickness value of the stainless steel pipe sample slice and the machining depth value of the stainless steel pipe fracture groove, and comparing the difference value with a fracture groove wall thickness standard value;

[0286] S55: obtaining a bevel angle value of the stainless steel pipe fracture groove by using an image measuring instrument, and comparing the bevel angle value with a standard value.

[0287] S51 comprises the following steps:

[0288] S511: aligning the stainless steel pipe with the fracture groove;

[0289] S512: cutting a 1 mm stainless steel pipe sample slice at the end of the stainless steel pipe;

[0290] The inner cavity axis of the stainless steel pipe is perpendicular to the cutting surface of the stainless steel pipe sample slice.

[0291] S52 comprises the following steps:

[0292] S521: cleaning the stainless steel pipe slice;

[0293] S522: obtaining a cutting surface profile of the stainless steel pipe slice by using an image measuring instrument;

[0294] S523: selecting four points on the cutting surface profile to obtain wall thickness values of the stainless steel pipe slice at the four points; wherein the four selected points are uniformly distributed on the cutting surface profile of the stainless steel pipe slice;

[0295] S524: calculating an average value of the wall thickness values of the stainless steel pipe slice at the four points, and taking the average value as the original wall thickness value of the stainless steel pipe.

[0296] S53 comprises the following steps:

[0297] S531: aligning the stainless steel pipe with the breaking groove;

[0298] S532: obtaining the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument;

[0299] S533: measuring the outer diameter value of the stainless steel pipe according to the profile of the stainless steel pipe;

[0300] S534: picking up two lowest points of the breaking groove on the profile of the stainless steel pipe, and measuring the distance between the two lowest points and the profile line of the end face of the stainless steel pipe respectively, which is the processing depth value of the breaking groove;

[0301] S535: rotating the stainless steel pipe by 90° around the rotation axis of the central axis of the inner cavity of the stainless steel pipe;

[0302] S536: sequentially obtaining the distance between the other two lowest points and the profile line of the end face of the stainless steel pipe according to steps S532, S533 and S534;

[0303] S537: calculating the average value of the distance between the above-mentioned four lowest points and the profile line of the end face of the stainless steel pipe, which is the processing depth value of the breaking groove.

[0304] In S54, the difference between the wall thickness value of the stainless steel pipe sample section and the processing depth value of the breaking groove of the stainless steel pipe is within ±0.05 mm.

[0305] S55 includes:

[0306] S551: aligning the stainless steel pipe with the breaking groove;

[0307] S552: obtaining the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument;

[0308] S553: picking up two lowest points of the breaking groove on the profile of the stainless steel pipe, and measuring the included angle between the two breaking groove profile lines passing through the same lowest point respectively to obtain two included angle values;

[0309] S554: rotating the stainless steel pipe by 90° around the rotation axis of the central axis of the inner cavity of the stainless steel pipe;

[0310] S555: sequentially obtaining the included angle between the other two breaking groove profile lines passing through the same lowest point according to steps S552 and S553;

[0311] S556: calculating the average value of the included angle between the above-mentioned four breaking groove profile lines passing through the same lowest point, which is the oblique angle value of the breaking groove.

[0312] Step 6: Use the image measuring instrument to detect whether the center line of the stainless steel pipe breaking groove coincides with the inner cavity axis of the stainless steel pipe.

[0313] Specifically, the method comprises the steps of:

[0314] S61: align the stainless steel pipe with the breaking groove;

[0315] S62: use the image measuring instrument to obtain the profile of the stainless steel pipe with the breaking groove;

[0316] S63: pick up two lowest points of the breaking groove on the profile of the stainless steel pipe, connect the two lowest points, measure the included angle between the connecting line of the two lowest points and the inner cavity axis of the stainless steel pipe, and compare the included angle with 90° to obtain the absolute value of the difference;

[0317] S64: take the inner cavity axis of the stainless steel pipe as the rotation axis, rotate the stainless steel pipe by 90° around the rotation axis;

[0318] S65: sequentially obtain the included angle between the connecting line of the two outer lowest points and the inner cavity axis of the stainless steel pipe according to steps S62, S63 and S64, and compare the included angle with 90° to obtain the absolute value of the difference;

[0319] S66: calculate whether the average value of the above two absolute values is within ±0.05°, if yes, the center line of the breaking groove of the stainless steel pipe coincides with the inner cavity axis of the stainless steel pipe.

[0320] Embodiment 2

[0321] The machining device for the super-fine long stainless steel pipe with the breaking groove comprises a tool electrode 1, a bearing assembly and a driving assembly installed on a machine tool, wherein the bearing assembly is used for clamping the stainless steel pipe 6, and the driving assembly is used for driving the tool electrode 1 to eccentrically move around the inner cavity axis of the stainless steel pipe 6 to realize the electric spark machining of the breaking groove 601 of the stainless steel pipe, thereby solving the problem that it is difficult to machine the breaking groove on the super-fine long stainless steel pipe.

[0322] Specifically, one end of the tool electrode 1 is in the shape of a circular ring, the inner circle end of the circular ring is the same as the shape of the breaking groove 601, and 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 the machine tool, so as to introduce current and transmit the current to the inner circle end, at this time, the inner circle end is a discharge end 101 which 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 discharge end 101 of the tool electrode 1 eccentrically moves around the inner cavity axis of the stainless steel pipe 6, at this time, the discharge end 101 comprises 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.

[0323] 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 long stainless steel pipe breaking groove 601.

[0324] 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 of the outer diameter of the stainless steel pipe 6, so as to facilitate determining the value of the single-sided feed amount O1O2; during machining, the tool electrode 1 is swung by the driving assembly, 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.

[0325] 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.

[0326] Wherein, S2=10μm; H1=0.5mm, H2=0.3mm, S1=2.058mm, at this time, O1O2=2.248mm.

[0327] 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.

[0328] 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.

[0329] Wherein, during machining, the electrical parameters meet:

[0330] Pulse width 40μs, pulse interval 26μs, average machining current 1A, average machining voltage 40V.

[0331] 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:

[0332] Wherein, during processing, the non-electric parameter satisfies:

[0333] 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.

[0334] 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.

[0335] 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.

[0336] 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.

[0337] 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.

[0338] 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.

[0339] Wherein, before placing the stainless steel pipe 6 on the equal-height positioning block 3, first, the tool electrode 1 needs to be centered and aligned, 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 align the stainless steel pipe 6.

[0340] The one end of the transmission rod 2 is connected with the tool electrode 1 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 to drive the transmission rod 2 to swing through the machine tool, and then the tool electrode 1 is driven to move through the transmission rod 2, so that the discharge end 101 of the tool electrode 1 performs eccentric motion around the central axis of the inner cavity of the stainless steel pipe 6.

[0341] In this way, the discharge end 101 of the tool electrode 1 performs eccentric motion around the central axis of the inner cavity of the stainless steel pipe 6 for one cycle, so that the machining of the breaking groove 601 of the stainless steel pipe is completed, the machining is in place at one time, and the machining efficiency is significantly improved.

[0342] The above-mentioned machining method is used to process the breaking grooves of 10 pieces of super-fine long stainless steel pipes #01-#10, and the machining parameters are shown in Table 1.

[0343] Table 1 Machining parameters

[0344]

[0345] The machining requirements are that the wall thickness of the breaking groove is 0.3±0.05 mm, and the oblique angle α is 90°.

[0346] The detection results are shown in Table 2.

[0347] Table 2 Detection results

[0348]

[0349]

[0350] The electrode consumption ratio is E / W*100%, wherein E is the diameter size change amount of the discharge end of the tool electrode, and W is the initial diameter size of the inner end of the tool electrode.

[0351] As shown in Table 2, the average value of the groove depth of the breaking grooves of the 10 pieces of stainless steel pipes machined by the present application is 0.2146 mm, the standard deviation is 0.01427, the dispersion coefficient is 0.07, the breaking groove angle is 90°, the average value of the wall thickness of the breaking groove is 0.299 mm, 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 super-fine long stainless steel pipe, the precision of the machined breaking groove is high and stable, the super-fine long stainless steel pipe is not damaged, and the consumption of the tool electrode is small.

[0352] 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.

[0353] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. 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 in the protection scope of the present application.

Claims

1. A method of producing an ultra-long stainless steel pipe with a breakage groove, characterized by, The method comprises the following steps: Step 1: the discharge end of the tool electrode is sleeved on the stainless steel pipe and makes eccentric motion in the inner cavity of the stainless steel pipe, the stainless steel pipe remains stationary, and the fracture groove of the stainless steel pipe is processed by electric spark; Step 2: the wall thickness of the fracture groove of the stainless steel pipe is detected by using an image measuring instrument and compared with a standard value; The step 2 comprises: S21: obtaining a stainless steel pipe sample slice without a fracture groove; S22: detecting and obtaining the wall thickness value of the stainless steel pipe sample slice by using an image measuring instrument; S23: detecting and obtaining the processing depth value of the fracture groove of the stainless steel pipe by using an image measuring instrument; S24: obtaining the difference value between the wall thickness value of the stainless steel pipe sample slice and the processing depth value of the fracture groove of the stainless steel pipe, and comparing the difference value with a standard value of the wall thickness of the fracture groove; The S21 comprises: S211: aligning the stainless steel pipe with the fracture groove; S212: cutting a 1mm stainless steel pipe sample slice at the end of the stainless steel pipe; The inner cavity axis of the stainless steel pipe is perpendicular to the cutting surface of the stainless steel pipe sample slice; Step 1 comprises using the working state of a plurality of electric spark processing point positions of the tool electrode arranged circumferentially around the stainless steel pipe to realize the processing of the fracture groove on the surface to be processed; The same electric spark processing point position is in a working state or a non-working state by changing the distance between the electric spark processing point position and the surface to be processed; The discharge end of the tool electrode comprises a plurality of electric spark processing point positions arranged circumferentially around the stainless steel pipe, and during processing, the plurality of electric spark processing point positions 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 fracture groove; The processing 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 inner cavity axis of the stainless steel pipe.

2. The method of claim 1, wherein, The step 2 further comprises: S25: obtaining the oblique angle value of the fracture groove of the stainless steel pipe by using an image measuring instrument, and comparing the oblique angle value with a standard value.

3. The method of claim 1, wherein, The S22 comprises: S221: cleaning the stainless steel pipe slice; S222: obtaining the cutting surface profile of the stainless steel pipe slice by using an image measuring instrument; S223: selecting four points on the cutting surface profile to obtain the wall thickness values of the stainless steel pipe slice at the four points; S224: calculating the average value of the wall thickness values of the stainless steel pipe slice at the four points, and taking the average value as the original wall thickness value of the stainless steel pipe.

4. The method of claim 1, wherein, The S23 comprises: S231: aligning the stainless steel pipe with the fracture groove; S232: obtaining the profile of the stainless steel pipe with the fracture groove by using an image measuring instrument; S233: measuring the outer diameter value of the stainless steel pipe according to the profile of the stainless steel pipe; S234: picking up two lowest points of the fracture groove on the profile of the stainless steel pipe, respectively measuring the distances between the two lowest points and the profile line of the end surface of the stainless steel pipe, and the distances are the processing depth values of the fracture groove; S235: rotating the stainless steel pipe by 90° around the inner cavity axis of the stainless steel pipe as the rotation axis; S236: sequentially obtaining the distances between the other two lowest points and the profile line of the end surface of the stainless steel pipe according to steps S232, S233 and S234. S237: Calculate the average value of the distance between the four lowest points and the profile line of the end face of the stainless steel pipe, and the average value is the breaking groove machining depth value.

5. The method of claim 2, wherein, The S25 comprises: S251: Align the stainless steel pipe with the breaking groove; S252: Obtain the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument; S253: Pick up two lowest points of the breaking groove on the profile of the stainless steel pipe, measure the included angle between the two profile lines of the breaking groove passing through the same lowest point, and obtain two included angle values; S254: Rotate the stainless steel pipe by 90° around the rotation axis of the central axis of the inner cavity of the stainless steel pipe; S255: Obtain the included angle between the two profile lines of the breaking groove passing through the same lowest point in sequence according to steps S252 and S253; S256: Calculate the average value of the four included angles between the two profile lines of the breaking groove passing through the same lowest point, and the average value is the breaking groove bevel angle value.

6. The method of claim 1, wherein, Further comprising step 3: detecting whether the center line of the breaking groove of the stainless steel pipe coincides with the central axis of the inner cavity of the stainless steel pipe by using the image measuring instrument.

7. The method of claim 6, wherein, The step 3 comprises: S31: Align the stainless steel pipe with the breaking groove; S32: Obtain the profile of the stainless steel pipe with the breaking groove by using the image measuring instrument; S33: Pick up two lowest points of the breaking groove on the profile of the stainless steel pipe, connect the two lowest points, measure the included angle between the connecting line of the two lowest points and the central axis of the inner cavity of the stainless steel pipe, and compare the included angle with 90° to obtain the absolute value of the difference value; S34: Rotate the stainless steel pipe by 90° around the rotation axis of the central axis of the inner cavity of the stainless steel pipe; S35: Obtain the included angle between the connecting line of the two lowest points and the central axis of the inner cavity of the stainless steel pipe in sequence according to steps S32, S33 and S34, and compare the included angle with 90° to obtain the absolute value of the difference value; S36: Calculate whether the average value of the two difference absolute values is within ±0.05°, and if so, the center line of the breaking groove of the stainless steel pipe coincides with the central axis of the inner cavity of the stainless steel pipe.

8. The method of claim 1, wherein: In step 1, the electrical parameters meet: Pulse width 30-60 μs, pulse interval 20-30 μs, average machining current 0.8-2 A, and average machining voltage 30-60 V.

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