Processing method of inclined tube of casing assembly

Abstract

The present invention discloses a method for processing an oblique tube of a casing assembly, comprising the following steps: tool design: according to the structural characteristics of the back of a pipe joint, a dovetail milling cutter for forming a conical surface and an inner arc circular surface in one step, and a trapezoidal milling cutter for forming an outer arc circular surface are designed. Clamping and positioning: the casing assembly blank is clamped and positioned on a special fixture. Tool setting: the tool length and tool radius of each processing tool are aligned on a tool setting instrument, and input into a CNC processing equipment. Position adjustment and verification: the inner hole of the end face of the pipe joint is rough-machined, and the zero point position is adjusted to the center of the pipe joint after measurement and verified by a table. Formal processing: according to a pre-set CNC processing program, conventional processing tools, dovetail milling cutters and trapezoidal milling cutters are used to process three oblique tube blanks in turn. The processing method of the present invention is not prone to tool letting-off phenomenon, has high processing accuracy, and the joint mark does not exceed 0.03mm, thereby improving the processing and forming quality of the pipe joint, reducing the scrap rate, and reducing production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of digital manufacturing and processing of casings, and in particular to a method for processing an inclined tube of a casing assembly. Background Art

[0002] like Figure 1 As shown in the figure, the diffuser casing component is made of titanium alloy ZTA15, with a complex structure. There are three pipe joints around the periphery. The casting position is uncertain and the deviation is large. Processing is carried out according to the theoretical position of the design drawing. In each batch of parts, several pieces are scrapped because the outer circle of the pipe joint cannot be machined or the wall thickness is too thin. The reverse side of the pipe joint has a complex structure, which is a difficult point to process. Figure 2 and Figure 3 As shown, the outer arc of R1 and the inner arc of R2 are connected by a 20° bevel. It is necessary to ensure the intersection size of the bevel to the end face and a smooth transition without joint marks between the arc and the bevel. If the joint marks exceed 0.03mm, it will be scrapped. The operator must repeatedly adjust the axial and radial dimensions to ensure the size of each pipe joint. The processing efficiency is low and the scrap rate of out-of-tolerance is high.

[0003] 1.1 The position of the welded pipe joint is uncertain, such as Figure 4 and Figure 5 As shown, two pipe joints are angled at 45 degrees to the part's support surface and must be machined on a five-axis DMU125P CNC machine. However, the CNC program defines the machining positions, which are not affected by changes in the pipe joint's position. The casting tolerance for the pipe joints in the diffuser casing assembly blank is 1 to 3 mm, while only 1 to 2 mm of machining allowance is allowed around the pipe joints. Due to the CNC program's predetermined positions, several pipe joints in each batch have wall thicknesses less than 2 mm, resulting in scrapped parts.

[0004] 1.2 Since the back bevel of the pipe joint is the fitting part, the size requirements are very strict, such as Figure 6 and Figure 7 As shown in the figure, the intersection sizes of the 20° bevel on the reverse side of the three pipe joints and the outer circle of the pipe joints are 2.46±0.03 (one place) and 2.83±0.03 (two places), respectively. The precision is high, but there is a serious tool deflection phenomenon in the actual processing, and the technical requirements cannot be met in one go.

[0005] 1.3 As Figure 8 As shown, R1 on the back of the pipe joint must be smoothly connected with the 20° bevel. If the joint mark exceeds 0.03, it will be scrapped. It is very difficult to control this part.

[0006] 1.4 As Figure 9 As shown in the figure, due to the presence of tool marks and chatter marks on the milling surface, it is difficult to ensure the surface roughness of 0.8 on the end face of the pipe joint. Summary of the Invention

[0007] The present invention provides a method for processing an inclined tube of a casing assembly, so as to solve the technical problems existing in the existing pipe joint processing, such as low processing efficiency, high scrap rate due to out-of-tolerance, serious tool retraction phenomenon, inability to meet technical requirements in one go and great processing difficulty.

[0008] The technical solution adopted in the present invention is as follows:

[0009] A method for processing an oblique tube of a casing component is used for processing three oblique tube blanks of the casing component blank in the circumferential direction into pipe joints respectively. The processing method comprises the following steps: tool design: according to the structural characteristics of the outer arc circular surface, conical surface and inner arc circular surface which are arranged in sequence along the axial direction and smoothly transitionally connected on the back side of the pipe joint, a dovetail milling cutter for forming the conical surface and the inner arc circular surface in one step, and a trapezoidal milling cutter for forming the outer arc circular surface are designed; clamping and positioning: the casing component blank is clamped and positioned on a special fixture connected to a CNC machining device; tool setting: the tool length and tool radius of each machining tool are measured on a tool setting instrument and input into the CNC machining device; position adjustment and verification: the inner hole of the end face of the pipe joint is rough-machined, and the zero point position is adjusted to the center of the pipe joint after measurement and verified by table; formal processing: according to a pre-set CNC machining program, conventional machining tools, dovetail milling cutters and trapezoidal milling cutters are used to process the three oblique tube blanks respectively in turn.

[0010] Furthermore, the dovetail milling cutter includes a first tool rod and a first cutter disc which are arranged and connected in sequence along the axial direction; the first tool rod is used to be connected to the tool mounting shaft of the CNC machining equipment; the first cutter disc is processed with a first cutting edge, and the first cutting edge is an outer convex edge extending obliquely upward from the back side of the cutter disc to the top surface, so as to be used for forming a conical surface and an inner arc circular surface at one time.

[0011] Furthermore, the first cutter rod is made of a material having rigidity and toughness; the first cutter disc is made of a material having sufficient hardness, and the first cutter disc is connected to the first cutter rod by welding.

[0012] Furthermore, the first cutter disc has a plurality of first structural teeth evenly distributed along its circumference, and a first cutting edge is provided at the same position on each first structural tooth; the projection line of the first cutting edge on the vertical plane has the same shape as the inner arc line of the inner arc circular section connected by the oblique line of the conical surface section.

[0013] Furthermore, the trapezoidal milling cutter includes a second tool rod and a second cutter disc which are arranged and connected in sequence along the axial direction; the second tool rod is used to be connected to the tool mounting shaft of the CNC machining equipment; the second cutter disc is machined with a second cutting edge, which is an inwardly concave edge extending from the top surface of the second cutter disc and sliding out from the end surface, so as to form an outer arc circular surface.

[0014] Furthermore, the second cutter disc has a plurality of second structural teeth evenly distributed along its circumference, and a second cutting edge is provided at the same position on each second structural tooth; each second cutting edge includes an inner arc edge, and a first bevel edge and a second bevel edge connected to the two ends of the inner arc edge; the arc angle of the inner arc edge is the same as the arc angle of the outer arc circular surface, the first bevel edge has an angle of 20° to 22° with the vertical plane, and the second bevel edge has an angle of 0° to 3° with the horizontal plane.

[0015] Furthermore, the step of "clamping and positioning" specifically includes the following steps: installing a special fixture on the machine tool of the CNC machining equipment of the spindle swing head; aligning the positioning center of the special fixture to set it to G54XY zero point, and aligning the angular direction of the special fixture to the positive direction of the X-axis; installing the casing assembly blank on the positioning circle of the special fixture, and fixing it and clamping it; aligning the outer circle runout of the casing assembly blank in the G54 center to be within 0.01mm, and aligning the upper surface of the casing assembly blank to set it to G54 Z zero point.

[0016] Furthermore, the step of "position adjustment and verification" specifically includes the following steps: machining an inner hole of φ19 and 2mm deep on the end face of the inclined tube blank, and measuring the distance between the upper, lower, left and right four points of the inner hole and the outer diameter of the end face of the inclined tube blank with a caliper, and entering the second programming zero point G55 after adjustment according to the four-point difference. The position of the G55 zero point is the center of the pipe joint; in order to verify whether the position of the pipe joint is correct after the offset, and whether the operator is correct in setting G55, add a section of alignment program to the CNC program; after the spindle calls the alignment table, it quickly reaches a position of 80 to 120mm away from the end face of the inclined tube blank. The operator does not need to adjust the coordinates to directly align the outer circle of the inclined tube blank. The difference between the upper, lower, left and right four points does not exceed 0.5mm.

[0017] Furthermore, the step "formal processing" specifically includes the following steps: calling the NC program through the DNC network system; raising the NC program by 80 to 120 mm to test run the NC program; and performing rough processing and fine processing on each processing part on the inclined tube blank according to the NC program.

[0018] Furthermore, the inclined tube blank includes the following specific processing steps: outer end face processing; end face outer circle processing at the outer end face; end face inner hole processing at the outer end face; conical surface, inner arc circular surface and outer arc circular surface processing on the back of the inclined tube blank, and during processing, a dovetail milling cutter is used to simultaneously process the conical surface and the inner arc circular surface to the processing allowance, and then a trapezoidal milling cutter is used to process the outer arc circular surface to the processing allowance, and then a dovetail milling cutter is used to process the processing allowance of the conical surface and the inner arc circular surface in place, and finally a trapezoidal milling cutter is used to process the processing allowance of the outer arc circular surface in place.

[0019] The present invention has the following beneficial effects:

[0020] In the processing method of the present invention, a special dovetail milling cutter and a trapezoidal milling cutter are processed according to the structural characteristics of the outer arc circular surface, the conical surface and the inner arc circular surface which are sequentially arranged along the axial direction and smoothly transitionally connected on the back side of the pipe joint. Therefore, when the dovetail milling cutter and the trapezoidal milling cutter are used to process the back side of the inclined pipe blank, it is not easy to have a tool-leaving phenomenon, so that the outer arc circular surface, the conical surface and the inner arc circular surface of the processed pipe joint back side have high precision, and can effectively ensure that the conical surface and the outer arc circular surface and the inner arc circular surface are smoothly transitionally connected, and the joint mark does not exceed 0.03mm, thereby improving the processing and molding quality of the pipe joint, reducing the scrap rate and reducing the production cost; on the other hand, the dovetail milling cutter and the trapezoidal milling cutter are used to process the back side of the inclined pipe blank ... The milling cutter and trapezoidal milling cutter are special tools for processing the pipe joint. Through the special design and use of the tool, the easy breakage of the tool in the existing conventional processing can be effectively reduced, thereby reducing the tool cost. At the same time, since the dovetail milling cutter can process the conical surface and the inner arc circular surface at the same time, it ensures the processing quality while greatly improving the processing efficiency and reducing the processing difficulty of the back of the pipe joint. In addition, in the step "position adjustment and verification", the inner hole of the end face of the pipe joint is rough-processed, and the zero point position is adjusted to the center of the pipe joint after measurement and verified by table, so as to effectively ensure the size of the pipe joint and reduce the scrapping of parts caused by the offset of the pipe joint.

[0021] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a schematic diagram of the end face of the diffuser casing assembly with three pipe joints;

[0024] Figure 2 yes Figure 1 Schematic diagram of the first type of pipe joint size;

[0025] Figure 3 yes Figure 1 Schematic diagram of the second type of pipe joint size;

[0026] Figure 4 yes Figure 2 Schematic diagram of the wall thickness of the middle pipe joint;

[0027] Figure 5 yes Figure 3 Schematic diagram of the wall thickness of the middle pipe joint;

[0028] Figure 6 yes Figure 2 Schematic diagram of the intersection size of the reverse bevel of the middle pipe joint;

[0029] Figure 7 yes Figure 3 Schematic diagram of the intersection size of the reverse bevel of the middle pipe joint;

[0030] Figure 8 Schematic diagram of the R angle of the pipe joint head surface;

[0031] Figure 9 Schematic diagram of the end face of the pipe joint;

[0032] Figure 10 It is a schematic diagram of pipe joint dimensions;

[0033] Figure 11 This is a schematic diagram of the main structure of the dovetail milling cutter;

[0034] Figure 12 yes Figure 11 Schematic diagram of the left view structure;

[0035] Figure 13 It is a schematic diagram of the main structure of the trapezoidal milling cutter;

[0036] Figure 14 yes Figure 13 Schematic diagram of the left view structure;

[0037] Figure 15 yes Figure 13 Schematic diagram of the enlarged structure at B in the middle;

[0038] Figure 16 It is a schematic diagram of the intersection size of the pipe joint;

[0039] Figure 17 It is a schematic diagram of the tool setting point;

[0040] Figure 18 This is a schematic diagram of the position adjustment of the inclined tube blank.

[0041] Legend

[0042] 10. Pipe joint; 101. Outer arc circular surface; 102. Conical surface; 103. Inner arc circular surface; 104. Outer end face; 105. End face outer circle; 106. End face inner hole; 20. Dovetail milling cutter; 21. First arbor; 22. First cutter disc; 23. First structural tooth; 231. First cutting edge; 30. Trapezoidal milling cutter; 31. Second arbor; 32. Second cutter disc; 33. Second structural tooth; 331. Second cutting edge. DETAILED DESCRIPTION

[0043] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0044] Reference Figure 1-3 and Figure 10 The preferred embodiment of the present invention provides a method for processing an oblique tube of a casing assembly, which is used to process three oblique tube blanks at the circumference of the casing assembly blank into pipe joints 10. The processing method includes the following steps:

[0045] Tool design: Based on the structural characteristics of the outer arc circular surface 101, conical surface 102 and inner arc circular surface 103 arranged in sequence along the axial direction and smoothly transitioned on the back of the pipe joint 10, a dovetail milling cutter 20 for forming the conical surface 102 and the inner arc circular surface 103 in one step, and a trapezoidal milling cutter 30 for forming the outer arc circular surface 101 are designed.

[0046] Clamping and positioning: The receiver assembly blank is clamped and positioned on a special fixture connected to the CNC machining equipment.

[0047] Tool setting: The tool length and tool radius of each processing tool are adjusted on the tool setting instrument and input into the CNC processing equipment.

[0048] Position adjustment and verification: perform rough machining on the inner hole 106 of the end face of the pipe joint 10, adjust the zero point position to the center of the pipe joint 10 after measurement, and verify it by measuring.

[0049] Formal processing: According to the pre-set CNC processing program, conventional processing tools, a dovetail milling cutter 20 and a trapezoidal milling cutter 30 are used to process the three oblique tube blanks in sequence.

[0050] In the processing method of the present invention, a special dovetail milling cutter 20 and a trapezoidal milling cutter 30 are processed according to the structural characteristics of the outer arc circular surface 101, the conical surface 102 and the inner arc circular surface 103 which are sequentially arranged along the axial direction and smoothly transitionally connected on the back side of the pipe joint 10. Therefore, when the dovetail milling cutter 20 and the trapezoidal milling cutter 30 are used to process the back side of the inclined pipe blank, it is not easy to have a tool backing phenomenon, so that the outer arc circular surface 101, the conical surface 102 and the inner arc circular surface 103 of the back side of the pipe joint 10 processed are of high precision, and the conical surface 102 can be effectively ensured to be smoothly transitionally connected with the outer arc circular surface 101 and the inner arc circular surface 103, respectively, with the joint mark not exceeding 0.03 mm, thereby improving the processing and molding quality of the pipe joint 10, reducing the scrap rate, and reducing production costs. Cost; on the other hand, the dovetail milling cutter 20 and the trapezoidal milling cutter 30 are special tools for processing the pipe joint 10. Through the special design and use of the tools, the situation where the tools are easy to break in existing conventional processing can be effectively reduced, thereby reducing the cost of tools. At the same time, since the dovetail milling cutter 20 can process the conical surface 102 and the inner arc circular surface 103 at the same time, while ensuring the processing quality, it greatly improves the processing efficiency and reduces the processing difficulty of the back of the pipe joint; In addition, in the step "position adjustment and verification", the inner hole 106 of the end face of the pipe joint 10 is rough-machined, and the zero point position is adjusted to the center of the pipe joint 10 after measurement and verified by table, so as to effectively ensure the size of the pipe joint and reduce the scrapping of parts caused by the offset of the pipe joint.

[0051] Alternatively, as Figure 11 As shown, the dovetail milling cutter 20 includes a first tool rod 21 and a first cutter disc 22 which are sequentially arranged and connected along the axial direction. The first tool rod 21 is used to be connected to the tool mounting shaft of the CNC machining equipment. The first cutter disc 22 is machined with a first cutting edge 231, and the first cutting edge 231 is an outer convex edge which extends obliquely upward from the back of the cutter disc to the top surface, so as to form a conical surface 102 and an inner arc circular surface 103 in one go. In this optional solution, the pipe joint 10 is composed of an outer arc circular surface 101 (radius R1), a conical surface 102 (inclination angle 20°), and an inner arc circular surface 103 (radius R2). It is necessary to ensure the three dimensions of the R1 / R2 / 20° inclined surfaces and the smooth transition between the outer arc circular surface 101 and the inner arc circular surface 103 and the conical surface 102, and the joint mark is less than 0.03mm. As Figure 10 As shown, the processing part R2 and the bevel are both located on the reverse side of the pipe joint. A tool with the same shape as the reverse side of the pipe joint needs to be designed for processing to ensure the relevant dimensions. In this optional solution, since the first cutting edge 231 is an outward convex edge extending upward from the back side of the cutter disc to the top surface, when the dovetail milling cutter 20 mills a circle around the pipe joint, the dimensions of R2 and the 20° bevel can be effectively guaranteed.

[0052] In the present invention, Figure 10 As shown, the casing assembly blank material is titanium alloy, which has high strength and good corrosion resistance. It is a difficult-to-process material. It has high cutting resistance and is prone to heat generation during machining. In order to ensure the surface roughness of the part is 1.6, the tool needs to be sharp to reduce the cutting force, thereby reducing the surface vibration of the part. The part material is titanium alloy, and the material of the tool cutting part must have sufficient hardness. Cemented carbide is used. Because the part is a thin-walled part, and the pipe joint processing part extends 60 to 70 mm from the part body, the rigidity is very poor, and vibration is prone to occur during processing. The CNC tool needs to have a certain toughness so that the tip of the tool will not break under cutting vibration. Therefore, in this optional solution, if Figure 11 As shown, the first shank 21 is made of a rigid and tough material, such as 45 steel, quenched to HRC 35-40. This provides a certain degree of rigidity and toughness, ensuring the strength and toughness of the cutter body. The first cutter disc 22 is made of a sufficiently hard material, such as cemented carbide, and is welded to the first shank 21. During cutting, the tool tip maintains sufficient hardness and the shank maintains a certain degree of toughness, preventing the tip from chipping under cutting forces. This solves the aforementioned technical problems, reduces tool cost, and minimizes surface chatter marks on the part.

[0053] In this option, if Figure 12As shown, the first cutter head 22 has a plurality of first structure teeth 23 evenly distributed along its circumference, and each first structure tooth 23 is provided with a first cutting edge 231 at the same position. The projection line of the first cutting edge 231 on the vertical plane has the same shape as the inner arc line of the inner arc circular surface 103 connected to the oblique line of the conical surface 102 section. In this optional solution, Figure 12 As shown, the first cutter disc 22 adopts a 6-tooth structure to reduce the machining allowance of each tooth of the tool, thereby reducing machining vibration; the diameter of the first cutter disc 22 is φ42~φ50mm, the diameter of the first tool rod 21 is 15~18mm, and the length of the 20° bevel is 10~15, which ensures the rigidity of the tool while completing the R2 and 20° bevel processing on the part at one time, thereby improving machining efficiency and reducing machining difficulty.

[0054] Alternatively, as Figure 13 and Figure 15 As shown, the trapezoidal milling cutter 30 includes a second tool rod 31 and a second cutter disc 32 which are sequentially arranged and connected along the axial direction. The second tool rod 31 is used to be connected to the tool mounting shaft of the CNC machining equipment. A second cutting edge 331 is machined on the second cutter disc 32. The second cutting edge 331 is an inner concave edge which extends from the top surface of the second cutter disc 32 and slides out from the end surface, so as to form an outer arc circular surface 101. In this optional solution, the pipe joint 10 is composed of an outer arc circular surface 101 (radius R1), a conical surface 102 (inclination angle 20°), and an inner arc circular surface 103 (radius R2). It is necessary to ensure the three dimensions of R1 / R2 / 20° bevel and the smooth transition between the outer arc circular surface 101 and the inner arc circular surface 103 and the conical surface 102, and the joint mark is less than 0.03mm. As shown in FIG. Figure 13 As shown, the processing part R1 is located on the back of the pipe joint, and a tool with the same shape as the back of the pipe joint needs to be designed for processing to ensure the relevant dimensions. In this optional solution, since the second cutting edge 331 is an inwardly concave edge extending from the top surface of the second cutter disc 32 and sliding out from the end surface, when the trapezoidal milling cutter 30 mills a circle around the pipe joint, the R1 size can be effectively guaranteed.

[0055] In this optional solution, since the trapezoidal milling cutter 30 only processes the outer R1 and ensures a smooth transition with the 20° bevel, and the machining allowance of the outer R1 part of the part is small, the tool wear is small. The trapezoidal milling cutter 30 adopts an integral structure and the material is high-speed steel W18Cr4V, which reduces the manufacturing difficulty and tool cost.

[0056] In this option, if Figure 14As shown, the second cutter disc 32 has a plurality of second structural teeth 33 uniformly distributed along its circumference, and a second cutting edge 331 is provided at the same position on each second structural tooth 33. The cutter disc adopts a 6-tooth structure, which is also used to reduce the cutting amount of each tooth, thereby reducing processing vibration. Each second cutting edge 331 includes an inner arc edge, and a first bevel edge and a second bevel edge connected to both ends of the inner arc edge. The arc angle of the inner arc edge is the same as the arc angle of the outer arc circular surface 101. The first bevel edge has an angle of 20° to 22° with the vertical plane, and the second bevel edge has an angle of 0° to 3° with the horizontal plane. In a specific embodiment of this optional scheme, as Figure 10 and Figure 15 As shown in the figure, the outer R1 of the part is smoothly connected with the 20° bevel and the φ40 outer circle. The tool adopts an inner concave blade design, and adopts a 22° first bevel blade to connect with the 20° bevel of the part. The angle is greater than the angle of the part bevel, which can ensure smooth connection with the 20° bevel of the part. The 3° second bevel blade is connected with the φ40 outer circle of the part to ensure that no joint marks will be produced on the outer circle of the outer R1 part, ensuring that the joint marks are less than 0.03mm.

[0057] Alternatively, as Figure 16 As shown, the CNC tools on the machining center, whether they are milling cutters, boring cutters, drill bits, or buried drill bits, generally use tool tip alignment to obtain accurate processing depth. However, the pipe joint 10 is processed on the back side, which is also an inclined surface. The tool tip alignment cannot grasp the exact position between the back side of the tool and the back side of the part. Therefore, in the existing operation, the operator can only move the milling cutter forward a few millimeters, and then slowly lift it up again and again. When approaching the size, the lifting height is only 0.03mm. Because the dimensional tolerance of the intersection is ±0.03mm, it takes many rounds of milling to process to the size. The processing process is complicated, and the efficiency and accuracy are low. In the present invention, Figure 17 As shown, by determining the specific tool setting point on the back of the dovetail milling cutter 20 on the diameter on the adjustment card, the precise tool length and tool radius can be directly set on the tool setting instrument. The operation is simple, time-saving and labor-saving, and the tool length and tool radius are highly accurate.

[0058] During actual processing, specific processing dimensions are given in the CNC program. The operator only needs to process according to the CNC program without repeatedly lifting the tool for measurement to ensure the intersection size of 2.83±0.03. However, in actual processing, the operator still lifts the tool by 0.1mm to compensate, and then processes it a second time after measurement to improve processing accuracy and prevent processing errors caused by inaccurate tool setting.

[0059] Optionally, the step of “clamping and positioning” specifically includes the following steps:

[0060] Install the special fixture on the machine tool of the CNC machining equipment with the spindle swing head.

[0061] The positioning center of the special fixture for alignment is set to G54XY zero point, and the angular direction of the special fixture for alignment is set to the positive direction of the X axis.

[0062] Install the receiver assembly blank onto the positioning circle of the special fixture and clamp it securely.

[0063] The outer circle runout of the casing assembly blank must be within 0.01mm when aligning the center of G54, and the upper surface of the casing assembly blank is set as G54 Z zero point.

[0064] Alternatively, as Figure 18 As shown, the step "position adjustment and verification" specifically includes the following steps:

[0065] Machine an inner hole of φ19 and 2mm deep on the end face of the inclined tube blank, and use calipers to measure the distances between the upper, lower, left and right points of the inner hole and the outer diameter of the end face of the inclined tube blank. After adjusting according to the difference between the four points, enter the second programming zero point G55. The position of the G55 zero point is the center of the pipe joint 10.

[0066] In order to verify whether the position of the pipe joint 10 is correct after the offset and whether the operator is correct in setting G55, a correction procedure is added to the NC program. The procedure is as follows:

[0067] T60 (alignment table)

[0068] M06

[0069] N1 G55G00G90X0Y0A0B0

[0070] N2 G00Z100

[0071] N3 M00

[0072] N4 M00

[0073] After the spindle calls the alignment table, it quickly reaches a position 80 to 120 mm away from the end face of the inclined tube blank. The operator does not need to adjust the coordinates to directly align the outer circle of the inclined tube blank. The difference between the four points of the upper, lower, left and right tables should not exceed 0.5 mm.

[0074] Optionally, the step of "formal processing" specifically includes the following steps:

[0075] Call NC programs through the DNC network system.

[0076] Raise 80 to 120 mm to test run the CNC program.

[0077] According to the CNC program, rough machining and fine machining are performed on each processing part of the inclined tube blank.

[0078] In this optional solution, the inclined tube blank includes the following specific processing steps:

[0079] The outer end surface 104 is processed.

[0080] The outer end surface 104 is machined to have an outer circle 105 .

[0081] The end surface inner hole 106 is machined at the outer end surface 104 .

[0082] The conical surface 102, the inner arc circular surface 103 and the outer arc circular surface 101 on the back of the bevel tube blank are machined. Since the bevel on the back of the pipe joint 10 has been machined to size, the processing area of ​​the trapezoidal milling cutter 30 is two tangent fillets. It is difficult to accurately align the tool length and tool radius on the tool setting instrument. The connection mark between the arc and the bevel cannot exceed 0.03. The trapezoidal milling cutter 30 can only be retracted little by little to align with the 20° bevel. This is very difficult and risky, and parts are often scrapped. Therefore, in the method of the present invention, during machining, the dovetail milling cutter 20 is first used to simultaneously machine the conical surface 102 and the inner arc circular surface 103 to the machining allowance (generally 1mm), and then Then, the trapezoidal milling cutter 30 is used to process the outer arc circular surface 101 to the processing allowance (generally 1mm), and then the dovetail milling cutter 20 is used to process the processing allowance of the conical surface 102 and the inner arc circular surface 103. Finally, the trapezoidal milling cutter 30 is used to process the processing allowance of the outer arc circular surface 101. In this processing method, first leave 1mm to mill out a 20° bevel, and then use the trapezoidal milling cutter 30 to completely align the 20° bevel, and then use the dovetail milling cutter 20 to mill the 20° bevel to size, then the trapezoidal milling cutter 30 can be processed to the same size to be qualified, and the processing operation is simple.

[0083] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for processing an inclined tube of a casing assembly, characterized in that: The method for processing three oblique tube blanks at the circumference of a casing assembly blank into pipe joints (10) comprises the following steps: Tool design: Based on the structural characteristics of the outer arc circular surface (101), the conical surface (102) and the inner arc circular surface (103) which are arranged in sequence along the axial direction and smoothly transitioned on the back side of the pipe joint (10), a dovetail milling cutter (20) for forming the conical surface (102) and the inner arc circular surface (103) in one step, and a trapezoidal milling cutter (30) for forming the outer arc circular surface (101) are designed; Clamping and positioning: clamping and positioning the receiver assembly blank on a special fixture connected to the CNC machining equipment; Tool setting: The tool length and radius of each machining tool are set on the tool setting instrument and input into the CNC machining equipment; Position adjustment and verification: rough machining the inner hole (106) of the end face of the pipe joint (10), and adjusting the zero point position to the center of the pipe joint (10) after measurement and verifying it by dialing; specifically, machining an inner hole of φ19 and 2mm deep on the end face of the inclined tube blank, and measuring the distances between the four points of the inner hole and the outer diameter of the end face of the inclined tube blank with a caliper, and inputting the second programming zero point G55 after adjustment according to the four-point difference, and the position of the G55 zero point is the center of the pipe joint (10); in order to verify whether the position of the pipe joint (10) after the offset is correct and whether the operator is correct in the process of setting G55, a aligning program is added to the CNC program; after the spindle calls the aligning table, it quickly reaches a position of 80 to 120mm away from the end face of the inclined tube blank, and the operator does not need to adjust the coordinates to directly align the outer circle of the inclined tube blank, and the upper, lower, left and right four-point dialing difference does not exceed 0.5mm; Formal processing: According to the pre-set CNC processing program, the three oblique tube blanks are processed in sequence using conventional processing tools, a dovetail milling cutter (20) and a trapezoidal milling cutter (30); The dovetail milling cutter (20) comprises a first cutter bar (21) and a first cutter disc (22) which are sequentially arranged and connected along the axial direction; the first cutter bar (21) is used to be connected to a tool mounting shaft of a numerical control machining device; a first cutting edge (231) is machined on the first cutter disc (22), and the first cutting edge (231) is an outer convex edge extending obliquely upward from the back surface of the cutter disc to the top surface, so as to form a conical surface (102) and an inner arc circular surface (103) at one time; The trapezoidal milling cutter (30) comprises a second cutter bar (31) and a second cutter disc (32) which are sequentially arranged and connected along the axial direction; the second cutter bar (31) is used to be connected to a tool mounting shaft of a numerical control machining device; a second cutting edge (331) is machined on the second cutter disc (32), and the second cutting edge (331) is an inner concave edge extending from the top surface of the second cutter disc (32) and sliding out from the end surface, so as to form an outer arc circular surface (101).

2. The method for processing the oblique tube of the casing assembly according to claim 1, characterized in that: The first cutter bar (21) is made of a material having rigidity and toughness; The first cutter disc (22) is made of a material having sufficient hardness, and the first cutter disc (22) is connected to the first cutter rod (21) by welding.

3. The method for processing the oblique tube of a casing assembly according to claim 1, characterized in that: The first cutter disc (22) has a plurality of first structural teeth (23) uniformly distributed along its circumference, and each first structural tooth (23) is provided with a first cutting edge (231) at the same position; The projection line of the first cutting edge (231) on the vertical plane has the same shape as the inner arc line of the inner arc circular surface (103) section connected by the oblique line of the conical surface (102) section.

4. The method for processing the oblique tube of a casing assembly according to claim 1, characterized in that: The second cutter disc (32) has a plurality of second structural teeth (33) uniformly distributed along its circumference, and each second structural tooth (33) is provided with a second cutting edge (331) at the same position; Each second cutting edge (331) comprises an inner arc edge, and a first oblique line edge and a second oblique line edge connected to both ends of the inner arc edge; The arc angle of the inner arc edge is the same as the arc angle of the outer arc circular surface (101), the first oblique edge has an included angle of 20° to 22° with the vertical plane, and the second oblique edge has an included angle of 0° to 3° with the horizontal plane.

5. The method for processing the oblique tube of a casing assembly according to claim 1, characterized in that: The step "clamping and positioning" specifically includes the following steps: Install the special fixture on the machine tool of the CNC machining equipment with the spindle swing head; The positioning center of the special fixture for alignment is set to G54XY zero point, and the angular direction of the special fixture for alignment is set to the positive direction of the X axis; Install the receiver assembly blank onto the positioning circle of the special fixture and clamp it securely; The outer circle runout of the casing assembly blank must be within 0.01mm when aligning the center of G54, and the upper surface of the casing assembly blank is set as G54 Z zero point.

6. The method for processing the oblique tube of a casing assembly according to claim 1, characterized in that: The step "formal processing" specifically includes the following steps: Call NC programs through the DNC network system; Raise 80-120mm to test run the CNC program; According to the CNC program, rough machining and fine machining are performed on each processing part of the inclined tube blank.

7. The method for processing the oblique tube of a casing assembly according to claim 6, characterized in that: The inclined tube blank includes the following specific processing steps: Processing of the outer end surface (104); Machining the outer circle (105) of the end surface at the outer end surface (104); Machining the end face inner hole (106) at the outer end face (104); The conical surface (102), the inner arc circular surface (103) and the outer arc circular surface (101) on the back of the inclined tube blank are processed, and during the processing, a dovetail milling cutter (20) is used to simultaneously process the conical surface (102) and the inner arc circular surface (103) to a processing allowance, and then a trapezoidal milling cutter (30) is used to process the outer arc circular surface (101) to a processing allowance, and then the dovetail milling cutter (20) is used to process the conical surface (102) and the inner arc circular surface (103) to a processing allowance in place, and finally the trapezoidal milling cutter (30) is used to process the processing allowance of the outer arc circular surface (101) to a processing allowance in place.

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