Processing method of hollow parts with uneven wall thickness

Abstract

The present invention relates to the field of mechanical manufacturing technology, and in particular to a method for processing hollow parts with uneven wall thickness. The processing method comprises: constructing a reference line at the feed end of the processing mold to obtain the angle between the radial projection of the built-in plane of the target hollow part and the reference line; setting a positioning block parallel to the built-in plane on the outside of the feed end of the processing mold; completing the alignment of the preformed hollow part blank at the positioning block corresponding to the built-in plane of the target hollow part based on the positioning block; and processing the preformed hollow part blank after alignment to obtain the built-in plane. The present invention realizes the visual positioning and correction of the intended processing plane by setting a reference line and a positioning block parallel to the radial projection of the built-in plane; at the same time, the positioning accuracy of the positioning block is optimized with the help of a photoelectric autocollimator, thereby further improving the positioning accuracy of the built-in plane, and greatly improving the processing accuracy compared with the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of metal material manufacturing, and in particular to a method for processing a hollow part with uneven wall thickness. Background Art

[0002] High-precision internal special-shaped hollow parts are widely needed in the aviation field, especially for the new generation of aviation materials represented by lightweight alloys (such as magnesium-aluminum alloys). Lightweight alloys and other materials cannot be welded or the welding accuracy is difficult to control, and the casting process is difficult to meet the precision requirements for internal special-shaped structures. Currently, the production of lightweight alloy hollow parts is mainly based on machine tool processing (turning, milling, etc.).

[0003] For the built-in planes parallel to the axis in high-precision hollow parts with uneven wall thickness, a common processing method is: fix the preformed hollow part blank and adjust the coordinate position of the tool for processing; this method has the defects of poor accuracy and difficult correction due to the large tool stroke, complex correction and program control; another common processing method is: fix the preformed hollow part blank on a rotary table, limit the tool to a limited area, and place different areas of the preformed hollow part blank in the limited processing area of ​​the tool in sequence by rotating the rotary table; this method generally requires the use of the angle scale of the rotary table to determine the rotation angle of the rotary table and then complete the alignment of the plane to be processed. At present, the indexing accuracy of the vertical rotary table in the existing technology is 0.01°, but due to the factors such as superimposed part deformation and accumulated errors in other directions during the processing process, the angular tolerance between the combined planes is not easy to guarantee, the risk of over-tolerance is large, and the yield rate is low, which still cannot meet the requirements of high-precision processing; at the same time, for high-precision hollow parts with uneven wall thickness, due to the asymmetric structure, the distribution position of each built-in plane inside the part is unique, the processing fault tolerance is low, and higher requirements are put forward for the positioning accuracy of the built-in plane. At present, the market is in urgent need of a processing device and method for a built-in plane parallel to the axial direction in a high-precision hollow part with uneven wall thickness. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a method for processing hollow parts with uneven wall thickness, so as to solve at least one of the problems in the prior art, such as low processing tolerance, low processing accuracy, and being greatly affected by the precision of the machine tool itself.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] The present invention provides a method for processing a hollow part with uneven wall thickness, comprising the following steps:

[0007] At least two reference points uniquely corresponding to the preformed hollow part blank are selected at the feed end of the processing mold to construct a reference line, and the angle between the radial projection of the built-in plane of the target hollow part and the reference line is obtained;

[0008] Based on the angle between the radial projection of the built-in plane of the target hollow part and the reference line, a positioning block parallel to the built-in plane of the target hollow part is arranged outside the feed end of the processing mold;

[0009] Based on the positioning block, the preformed hollow part blank is aligned on the built-in plane of the positioning block corresponding to the target hollow part;

[0010] The preformed hollow part blank after alignment is processed to obtain the built-in plane.

[0011] Preferably, the positioning of the reference point includes: matching and connecting the preformed hollow part blank and the processing mold at the reference point to position the reference point.

[0012] Preferably, the matching connection at the reference point includes: matching connection between the preformed hollow part blank and the processing mold through positioning pins.

[0013] Preferably, the polyhedron is rotated α based on the central angle corresponding to the reflecting surface of the polyhedron M ', set the positioning block; where α M ' is the angle between the Mth positioning block and the reference line.

[0014] Preferably, setting the positioning block comprises the following steps:

[0015] The optional static position after the processing mold is installed on the horizontal rotary table is taken as the initial position, the geometric center of the outer side surface of the feed end of the processing mold is taken as the origin, the coordinate axis x' axis is set in the direction parallel to the reference line at the initial position, the coordinate axis z' axis is set in the radial plane of the processing mold and is perpendicular to the coordinate axis x' axis, and the y' axis is set in the direction of the perpendicular line passing through the origin and perpendicular to the coordinate axis x' axis and the z' axis, so as to construct the x'y'z' three-axis coordinate system;

[0016] Get the angle α between the Mth positioning block and the reference line M '; A polyhedral prism is coaxially fixed in the center area of ​​the horizontal rotary table, and the polyhedral prism is rotated from the initial position by α M ', set the Mth positioning block in the x'z' plane; M is a positive integer.

[0017] Preferably, the polyhedron is rotated α M ', including: correcting the rotation angle of the polyhedral prism through a photoelectric autocollimator.

[0018] Preferably, the correction of the rotation angle of the polyhedron includes:

[0019] Polyhedron rotation αM ', set the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; adjust the angle of the photoelectric autocollimator relative to the x' axis so that the reading of the photoelectric autocollimator on the optional reflective surface of the polyhedral prism is 0, and fix the photoelectric autocollimator as the initial position of the polyhedral prism;

[0020] Rotate the polyhedron by k reflecting surfaces, fine-tune the rotation angle of the polyhedron so that the reading of the photoelectric autocollimator is 0, and fix the polyhedron to complete the calibration; where k satisfies: k = α M '×N / 360, α M ' is the angle between the Mth positioning block and the reference line, k is a positive integer, and N is the number of reflecting surfaces of the polyhedral prism.

[0021] Preferably, between the pre-machining process and the alignment of the built-in plane, a heat treatment process of the preformed hollow part blank is also included.

[0022] Preferably, the heat treatment of the preformed hollow part blank comprises the following steps:

[0023] Heat treatment at 120±10℃ for 2h~6h, then air cool to room temperature;

[0024] Treat at -50±5℃ for 1h~3h, then return to room temperature;

[0025] Heat treat at 120±10℃ for 2h~6h, then air cool or cool in the furnace to room temperature.

[0026] Preferably, the machining program of the built-in plane is obtained and generated by machining programming software based on the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the finished machined part.

[0027] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0028] (1) The present invention sets a consistent reference line and a positioning block parallel to the built-in plane in the processing mold and the preformed hollow part blank, so that the absolute position relationship of the built-in plane of the target hollow part relative to the part is transmitted and converted into the angular relationship between the positioning block and the reference line, which greatly reduces the difficulty of positioning the built-in plane of the target hollow part in the part.

[0029] (2) The present invention transmits the angular relationship of the radial projection of the axially parallel built-in plane to the angular relationship of the corresponding positioning block by setting a positioning block parallel to the radial projection of the axially parallel built-in plane of the target hollow part, thereby decomposing the machining of the axially parallel built-in plane into two parts: axially parallel built-in plane alignment and positioning and axially parallel built-in plane cutting. Therefore, the present invention does not need to add a positioning function module when designing the machining program. Compared with the prior art, the workpiece to be machined is fixed and only the machining tool is used for cutting, which reduces the complexity of the program design and the elongation of the machining tool, and improves the machining accuracy and reliability.

[0030] (3) The present invention converts the alignment of the axially parallel built-in plane into the horizontal adjustment of the corresponding positioning block, and converts the positional relationship of the built-in plane of the target hollow part that is abstract and invisible before processing into the angular relationship between the positioning blocks and between the positioning blocks and the horizontal plane. Before processing the built-in plane, the positioning blocks can be measured and corrected to achieve the correction of the built-in plane of the target hollow part, thereby improving the processing accuracy.

[0031] (4) The present invention uses a rotating method for the preformed hollow part blank to realize processing of different areas of the preformed hollow part blank. The tool only needs to move within a local range on one side of the area to be processed, thereby reducing the tool processing stroke. Compared with the processing method in the prior art in which the processed part is fixed and the tool is moved to each processing area, the cumulative error caused by the increase in the tool stroke is reduced, thereby improving the accuracy.

[0032] (5) The present invention sets a positioning block parallel to the radial projection of the built-in axially parallel plane, and uses the parallel transmission law to convert the angular relationship of the built-in plane of the target hollow part on the radial plane projection into the angular relationship between the positioning blocks; further, the present invention uses a photoelectric autocollimator to correct the angular relationship between the positioning blocks, which improves the accuracy compared to the angle scale provided by the vertical rotary table, thereby achieving precise positioning of the built-in plane of the target hollow part.

[0033] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0035] Figure 1It is a schematic diagram of an assembly of a hollow part with uneven wall thickness and a processing mold in a 45° top view according to one embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of a 45° top view of a hollow part with uneven wall thickness formed in one embodiment of the present invention;

[0037] Figure 3 It is a cross-sectional view of the AA surface of a hollow part with uneven wall thickness in one embodiment of the present invention;

[0038] Figure 4 It is a cross-sectional view of the AA plane of a hollow part blank with uneven wall thickness in one embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of the assembly of an unformed hollow part with uneven wall thickness, an external pressing plate and a positioning block from a 45° top view in one embodiment of the present invention;

[0040] Figure 6 A schematic diagram of a processing device and an installation method for a hollow part with uneven wall thickness in one embodiment of the present invention;

[0041] Figure 7 This is a flow chart of a method for processing a hollow part with uneven wall thickness in one embodiment of the present invention;

[0042] Figure 8 The present invention is a flowchart of a method for positioning a built-in axial parallel plane of a hollow part with uneven wall thickness in one embodiment of the present invention.

[0043] Reference numerals:

[0044] External pressure plate 1; tie rod 2; bottom fixing part 3; hollow part 4; rotary table 5; machine tool platform 6; machine tool spindle 7, processing tool 8; positioning block 101; first positioning block 1011; second positioning block 1012; center hole 102; edge solid area 103; tie rod mounting hole 104; first positioning through hole 105; positioning pin 106; second positioning hole 401; axially parallel built-in plane 402; built-in plane 402' of target hollow part; first built-in plane 4021; second built-in plane 4022; first target plane 4021'; second target plane 4022'; part body 403; processing range 405 of processing tool. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0046] In order to clearly explain the technical solution of the present invention, the following technical terms are further defined:

[0047] Alignment:

[0048] The present invention defines alignment as a state in which the plane to be processed is parallel to the horizontal plane.

[0049] Straight line 1 With straight line l 2 The angle between two lines:

[0050] Put the straight line l 1 Rotate counterclockwise to the same position as l 2 The angle of rotation when overlapping.

[0051] The current vertical rotary table indexing accuracy in the prior art is higher than 0.01°. Limited by the accuracy of the vertical rotary table, the horizontal alignment accuracy of the plane to be processed is difficult to further improve. To solve the above problems, the present invention provides a processing device and method for a built-in plane parallel to the axial direction in a high-precision hollow part that does not rely on the indexing accuracy of the rotary table.

[0052] The present invention provides a method for processing a hollow part with uneven wall thickness, such as Figure 7 As shown, the following steps are included:

[0053] Step 1: Select at least two reference points uniquely corresponding to the preformed hollow part blank at the feed end of the processing mold to construct a reference line, and obtain the angle between the radial projection of the built-in plane of the target hollow part and the reference line;

[0054] Specifically, the preformed hollow part blank is clamped and fixed inside the processing mold, one end of the processing mold is fixedly connected to the vertical rotary table, and the other end serves as a feed end; the preformed hollow part blank is provided with a positioning and matching connection structure with the processing mold on one side of the feed end, so that the preformed hollow part blank and the processing mold are matched and connected at the reference point, so that the reference line is transferred from the feed end of the processing mold to the preformed hollow part blank, and at the same time, the absolute position relationship of the built-in plane of the target hollow part relative to the part is converted into the angle between the radial projection of the built-in plane of the target hollow part and the reference line.

[0055] Step 2: Based on the angle between the radial projection of the built-in plane of the target hollow part and the reference line, a positioning block parallel to the built-in plane of the target hollow part is set on the outer side of the feed end of the processing mold; wherein the radial projection of the built-in plane refers to the projection of the built-in plane on the radial plane.

[0056] Specifically, according to the angle between the radial projection of the built-in plane of each target hollow part and the reference line, the angle between the corresponding positioning block parallel to the built-in plane of each target hollow part and the reference line is determined, and each positioning block is sequentially arranged according to the angle of the positioning block.

[0057] Specifically, Figure 6 As shown, the processing device includes: an external pressure plate 1, a pull rod 2, a bottom fixing part 3, a vertical rotary worktable 5, a machine tool platform 6, a machine tool spindle 7 and a processing tool 8; the external pressure plate 1 is located at one end of the pull rod, the bottom fixing part 3 is located at the other end of the pull rod 2, the external pressure plate 1 and the bottom fixing part 3 are fixedly connected by the pull rod 2, and a fixing area for clamping and fixing the preformed hollow part blank is provided between the external pressure plate 1 and the bottom fixing part 3; a positioning block 101 parallel to the built-in axial parallel plane of the preformed hollow part blank is provided at the end of the external pressure plate 1 away from the bottom fixing part 3; the vertical rotary worktable 5 is fixedly connected to the end of the bottom fixing part 3 facing away from the external pressure plate 1; one side of the machine tool platform 6 is movably connected to the vertical rotary worktable 5, and the other side of the machine tool platform 6 is movably connected to the machine tool spindle 7; the processing tool 8 is arranged at the end of the machine tool spindle 7 on the side close to the external pressure plate 1.

[0058] It should be noted that: there are multiple installation positions for the positioning blocks that meet the angle relationship with the reference positioning block, and the straight lines where all the installation positions are located are parallel to each other and have the same angle with the reference positioning block; an installation position is selected on the outer side of the external pressure plate 1 to set the positioning block without obstacles, and the positioning block set at this installation position should not hinder the other structures and functional settings on the same side of the external pressure plate 1. Based on this, the angle between each positioning block set on the external pressure plate 1 of the present invention and the reference line is the same as the angle between the projection of the built-in plane corresponding to each positioning block on the radial plane and the reference line; the angular relationship of the positioning blocks set by the above method corresponds to the angle of the projection of the axially parallel built-in plane to be processed on the radial plane, and the inclination angle of the built-in plane of the target hollow part relative to the horizontal plane is converted into the angle between the positioning block and the horizontal plane; and the inclination angle of the built-in plane of each target hollow part relative to the horizontal plane is uniquely determined relative to the reference line.

[0059] Step 3: Based on the positioning block, the preformed hollow part blank is aligned on the built-in plane of the positioning block corresponding to the target hollow part;

[0060] Specifically, the rotation angle of the vertical rotary table is adjusted to the level of the positioning block. Based on the principle of parallel transmission, the built-in plane of the target hollow part corresponding to the positioning block can be placed horizontally and within the processing range of the machining tool, thereby completing the alignment of the built-in plane of the target hollow part; the machining range of the machining tool is limited to a fixed area on one side relative to the center of the hollow part through program control.

[0061] Step 4: Process the aligned preformed hollow part blank to obtain the built-in plane; specifically, based on the processing program, the processing tool processes from the inner wall to the outer wall of the preformed hollow part blank to remove excess material and obtain the built-in plane of the target hollow part.

[0062] On the one hand, by setting a consistent reference line and a positioning block parallel to the built-in plane in the processing mold and the preformed hollow part blank, the absolute position relationship of the built-in plane of the target hollow part relative to the part is transmitted and converted into the angular relationship between the positioning block and the reference line, which greatly reduces the difficulty of positioning the built-in plane of the target hollow part in the part.

[0063] On the other hand, the built-in plane parallel to the axis to be processed is abstract and invisible before the processing is completed, while the positioning block is concrete and visible. The advantages of using the positioning block for zeroing in the present invention are: compared with the prior art, the present invention converts the zeroing of the built-in plane parallel to the axis to be processed into the horizontal adjustment of the corresponding positioning block, and the positioning block can be measured and corrected before processing the built-in plane, so as to realize the correction of the built-in plane parallel to the axis to be processed and improve the processing accuracy;

[0064] On the other hand, the processing error of the tool is proportional to its stroke. Compared with the prior art, the present invention adopts a rotation method of the preformed hollow part blank to realize the processing of different areas of the preformed hollow part blank. The tool only needs to move within a local range on one side of the area to be processed, which reduces the tool processing stroke. Compared with the prior art, in which the tool accumulates and moves between various processing areas, the cumulative error of the tool caused by the increase in stroke is reduced, thereby improving the accuracy.

[0065] Specifically, the positioning of the reference point in step 1 includes: the preformed hollow part blank is matched and connected with the processing mold at the reference point to achieve the positioning of the reference point. Figure 3 As shown, the edge solid area 103 is provided with two first positioning through holes 105; Figure 4 As shown, a second positioning hole 401 is provided on one side where the preformed hollow part blank is connected to the external pressure plate 1; one end of the first positioning through hole 105 is axially movably connected to the preformed hollow part blank; the radial rotation of the preformed hollow part blank can be locked by matching the positioning pin 106 with the first positioning through hole 105 and the second positioning hole 401 to prevent radial relative sliding, thereby ensuring stability and precision during processing.

[0066] During implementation, the centers of the two first positioning through holes 105 are selected as reference points, and the line connecting the centers of the two first positioning through holes 105 is selected as the reference line.

[0067] Specifically, the angle between the radial projection of the built-in plane and the reference line of the target hollow part in step 1 can be obtained from the design parameters of the hollow part: the hollow part drawing contains the angle information between each built-in plane radial projection and the reference line.

[0068] Specifically, in step 2, a positioning block parallel to the built-in plane of the target hollow part is set on the outside of the feed end of the processing mold, and the remaining positioning blocks are set according to the angle with the reference line. It should be noted that the positioning block can be set on multiple parallel lines that meet the angle relationship with the reference line, and there are multiple feasible installation positions for the positioning block to translate on the same parallel line. Therefore, it is necessary to select an installation position on the outer side of the external pressure plate 1 where the positioning block can be set without obstacles. The positioning block set at this installation position should have no obstacles to the other structures and functional settings on the same side of the external pressure plate 1.

[0069] Specifically, setting a positioning block parallel to the built-in plane of the target hollow part includes the following steps:

[0070] S201: Taking an optional static position after the processing mold is installed on the horizontal rotary table as the initial position, taking the geometric center of the outer side surface of the feed end of the processing mold as the origin, setting a coordinate axis x' in the direction parallel to the reference line at the initial position, setting a coordinate axis z' in the radial plane of the processing mold in the direction perpendicular to the coordinate axis x', setting a y' in the direction of the perpendicular line passing through the origin and perpendicular to the coordinate axis x' and z', and constructing an x'y'z' three-axis coordinate system;

[0071] Specifically, the external pressure plate 1 is coaxially fixed to the horizontal rotary table with a group of first positioning through holes 105 which are centrally symmetrical with respect to the geometric center of the external pressure plate 1; the geometric center of the outer side of the feed end of the processing mold is taken as the origin, the center line of the first positioning through holes 105 at the initial position is taken as the coordinate axis x' axis and the reference line, and the coordinate axis z' axis is established perpendicular to the x' axis direction in the plane of the horizontal rotary table at the initial position.

[0072] S202: Obtaining the angle α between the Mth positioning block and the reference line M '; A polyhedral prism is coaxially fixed in the center area of ​​the horizontal rotary table, and the polyhedral prism is rotated from the initial position by α M ', set the Mth positioning block in the x'z' plane; M is a positive integer.

[0073] Specifically, the polyhedron in S202 rotates α M ' degrees, rotate the polyhedron by α based on the central angle of the polyhedron corresponding to the reflection surface M 'Spend.

[0074] Specifically, in S202, the side surface of the polyhedron is a rectangular reflective surface with the same size as the vertical horizontal surface.

[0075] Specifically, the number of faces N of the polyhedron in S202 needs to be selected based on k=α M' / (360 / N), k is a positive integer; 360 / N is the center angle corresponding to a single reflection surface of the polyhedron. In order to match the correction of the polyhedron reflection surface by the photoelectric autocollimator, the rotation of the polyhedron is based on the center angle corresponding to a single reflection surface as a basic unit. In the case of less than one basic unit (k is not an integer), the value of N should be adjusted to satisfy k to be a positive integer, and the number of reflection surfaces of the polyhedron is determined to obtain a suitable polyhedron.

[0076] It should be noted that S201-S202 are implemented on a horizontal rotary worktable, which is different from the vertical rotary worktable described in steps 1-3: the rotation plane of the horizontal rotary worktable is set horizontally, and it is the worktable of the horizontal machining center; the rotation plane of the vertical rotary worktable is set vertically to the horizontal plane.

[0077] It should be noted that, in order to ensure the consistent angle relationship relative to the first positioning block, the first positioning block, the second positioning block, ..., the Mth positioning block are set in S202, and the polyhedron rotates in the same direction.

[0078] Furthermore, in order to improve the rotation accuracy of the polyhedral prism rotation angle, the polyhedral prism is rotated α in S202. M ' degrees, including the precision correction of the rotation angle of the polyhedron by the photoelectric autocollimator.

[0079] Specifically, the photoelectric autocollimator can measure the deflection angle between its own emitted light and the received reflected light signal, with a measurement accuracy higher than 0.8″; by adjusting the angle between the photoelectric autocollimator and the polyhedral prism reflection surface, when the photoelectric autocollimator reading is 0, the polyhedral prism reflection surface is perpendicular to the emitted light direction of the photoelectric autocollimator.

[0080] Specifically, the precision correction of the rotation angle of the polyhedron by the photoelectric autocollimator includes the following steps:

[0081] S2021: Polyhedron Rotation α M ', set the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; adjust the angle of the photoelectric autocollimator relative to the x' axis so that the reading of the photoelectric autocollimator on the optional reflective surface of the polyhedral prism is 0, and fix the photoelectric autocollimator as the initial position of the polyhedral prism;

[0082] S2022: Rotate the polyhedron by k reflecting surfaces, fine-tune the rotation angle of the polyhedron so that the photoelectric autocollimator reading is 0, and fix the polyhedron to complete the calibration; wherein k satisfies: k=α M '×N / 360, α M ' is the angle between the Mth positioning block and the reference line, k is a positive integer, and N is the number of reflecting surfaces of the polyhedral prism.

[0083] It should be noted that when the reading of the photoelectric autocollimator in S2021 and S2022 is 0, the direction of the emitted light from the photoelectric autocollimator and the reflection surface of the polyhedron after rotating k reflection surfaces from the initial position are strictly perpendicular, with an accuracy greater than 0.08", which has higher positioning accuracy than the angle scale of the horizontal rotary table.

[0084] In the prior art, the positioning of the built-in plane of the target hollow part is based on the rotation angle scale of the vertical rotary table on the processing machine tool, and thus the positioning accuracy of the built-in plane of the target hollow part is affected by the rotation angle accuracy of the vertical rotary table; compared with the prior art: on the one hand, the present invention sets a positioning block parallel to the radial projection of the built-in axial parallel plane to be processed, and utilizes the parallel transfer law to convert the angular relationship of the radial plane projection of the built-in plane of the target hollow part into the angular relationship between the positioning blocks; further, the present invention utilizes a photoelectric autocollimator to correct the angular relationship between the positioning blocks, which improves the accuracy compared to the angle scale of the vertical rotary table, and realizes the precise positioning of the built-in plane of the target hollow part.

[0085] During implementation, the side of the bottom fixing member 3 in step 2 away from the pull rod 2 is fixedly connected to the vertical rotary table, thereby realizing radial rotation of the preformed hollow part blank, adjusting the positioning block to horizontal, thereby realizing the built-in plane alignment of the target hollow part corresponding to the positioning block.

[0086] Furthermore, in order to improve the accuracy of the positioning block timing, step 3 includes using a dial indicator to calibrate the positioning block position, which specifically includes the following steps:

[0087] S301: adjusting the rotation angle of the horizontal rotary table to which the positioning block is fixedly connected, and setting the positioning block approximately horizontally;

[0088] S302: A dial indicator is mounted on the machine tool spindle, and the machine tool spindle is moved left and right along the projection line of the x'-axis on the horizontal plane, and the angle of the positioning block is fine-tuned according to the number indicated by the percentage pointer, until the dial indicator pointer reading changes below the threshold when the dial indicator needle slides from one end to the other end on the positioning block, and the positioning block is determined to be strictly horizontal.

[0089] It should be noted that in S301, the positioning block can be set in an approximately horizontal direction by visual judgment or by measuring the angle with an angle ruler; however, the positioning accuracy of the positioning block set by these two methods cannot meet the requirements of precision machining; therefore, it is necessary to further correct the vertical relationship of the positioning block relative to the z-axis.

[0090] During implementation, the dial indicator displacement probe is used to measure the displacement change of the side to be measured relative to the dial indicator; by installing a dial indicator on the machine tool spindle, parallel movement along the x' axis can be achieved, and the dial indicator displacement probe contacts the positioning block and the side to be measured (top or bottom side); if the side to be measured is not parallel to the projection line, the dial indicator displacement probe has a displacement change on the side to be measured, resulting in a change in the percentage indication number; if the side to be measured is parallel to the projection line, the change in the percentage indication number cannot be detected or is 0.

[0091] Specifically, the change of the dial indicator pointer indication is introduced to evaluate the horizontal degree of the positioning block: if η is less than 1%, it is judged that the alignment is completed; the change indication η satisfies: η=S max -S min , where S max S is the maximum value of the dial indicator pointer. min It is the minimum value indicated by the dial indicator pointer.

[0092] Preferably, the ratio of the length to the width or height of the positioning block is greater than 2; an increase in the ratio of the length to the width or height of the positioning block is conducive to obtaining a larger height difference at both ends of the top of the positioning block, so that the dial indicator has a larger indication change and obtains a more sensitive signal.

[0093] Compared with the prior art, the present invention realizes the alignment of the built-in plane of the target hollow part by setting a positioning block parallel to the built-in plane of the target hollow part based on the horizontal setting of the positioning block, thereby avoiding the limitation of the positioning accuracy of the built-in plane of the target hollow part by the angle scale accuracy of the vertical rotary table. Furthermore, the present invention greatly improves the positioning accuracy from 0.01° to 0.08″ by correcting the position of the positioning block in the state of alignment by a dial indicator.

[0094] Optionally, the machining program in step 4 may be generated by machining programming software based on the three-dimensional models of the preformed hollow part blank and the machined part product.

[0095] Specifically, the machine tool processing is based on the x, y, and z three-axis spatial coordinate system set by itself, wherein the x-axis is set parallel to the horizontal plane, the y-axis is set parallel to the axial direction of the processed part, and the z-axis is set perpendicular to the horizontal plane; the machine tool processing is performed through program settings on each point in the F (x, y, z) processing area of ​​the preformed hollow part blank that has completed the built-in plane alignment operation to be processed.

[0096] During implementation, the processing range of the processing tool 8 is limited to a fixed area on one side relative to the center of the preformed hollow part blank through program control; correspondingly, the rotation angle of the vertical rotary table 5 is adjusted to realize the processing of different areas of the hollow part 4.

[0097] It should be noted that the control program of the machine tool does not include a recognition module for the position of the preformed hollow part blank. Therefore, before processing the hollow part 4 to obtain the corresponding built-in plane to be processed, the built-in plane to be processed of the preformed hollow part blank needs to be aligned.

[0098] Specifically, step 4 of machining parts using a machine tool includes the following steps:

[0099] S401: constructing a three-dimensional model of a preformed hollow part blank and a three-dimensional model of a finished processed part in a programming software;

[0100] S402: The programming software generates a processing program based on the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the processed part finished product;

[0101] S403: The machine tool processes the aligned part based on the processing program to obtain a finished part with a corresponding built-in plane.

[0102] Specifically, in S401, the three-axis spatial coordinate system of x, y, and z set by the machine tool itself is used, wherein the x-axis is parallel to the horizontal plane, the y-axis is parallel to the axial direction of the processed part, and the z-axis is perpendicular to the horizontal plane, to construct a three-dimensional model of the preformed hollow part blank and a three-dimensional model of the processed part product; in S402, the programming software compares the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the processed part product to confirm the area to be processed F (x, y, z) and generate a processing program.

[0103] In this field, parts processing is often divided into two or more processing steps: on the one hand, it prevents local overheating during long-term processing, expansion and deformation of the tool and material, and drift of the reference position, which affect the processing accuracy; on the other hand, different processing accuracies have different requirements for the tool, and rough processing causes greater wear on the tool, reducing the service life of the tool.

[0104] Preferably, between step 2 and step 3, a pre-processing process of the preformed hollow part blank is also included to further improve the above technical problems, including the following steps:

[0105] S204: Establishing a reference line and obtaining an angle α between the reference line and the first positioning block 0 Specifically, a set of centrally symmetrical first positioning through holes 105 is selected, and the center line of the two is used as the reference line of the first positioning block, and the angle α between the reference line and the first positioning block is obtained. 0 ;

[0106] S205: Fix the preformed hollow part blank on the rotary table through the processing mold, and obtain the inclination angle α between the reference line and the horizontal plane - , based on the angle α 0 and angle α - Get the rotary table rotation angle α required for the first positioning block to alignt1 ; Based on α t1 Complete the preliminary alignment of the first built-in plane; specifically, α t1 Satisfaction: α t1 =α - +90°-α 0 ;

[0107] S206: processing the mold to be processed after the preliminary alignment of the first built-in plane is completed with a margin of 0.2 mm to 0.6 mm;

[0108] S207: Based on alpha t1 and the angle α between the first built-in plane and the second built-in plane 1 Get the rotary table rotation angle α required for the second positioning block to align t2 , based on α t1 The angle α between the first built-in plane and the third built-in plane 2 Get the rotary table rotation angle α required for the third positioning block to align t3 , ..., based on α t and the angle α between the Nth built-in plane and the first built-in plane N Get the rotary table rotation angle α required for the Nth positioning block to align tN Specifically, the Nth positioning block aligns the required rotary table rotation angle α tN , satisfying: α tN =α t1 +α N ; Based on α t2 , …, α tN The second built-in plane, ..., the Nth built-in plane are preliminarily aligned; the preformed hollow part blank having the second built-in plane, ..., the Nth built-in plane preliminarily aligned is processed with a margin of 0.2mm to 0.6mm.

[0109] Preferably, in order to ensure positioning accuracy, the angle α between the reference line and the first positioning block is obtained by a photoelectric autocollimator. 0 .

[0110] The present invention provides a pre-machining process for the built-in plane of the target hollow part before fine machining, which can remove the raw material surplus designed in the preformed hollow part blank, reduce the burden of the tool during precise machining, avoid tool overheating and raw material aging problems caused by too long fine machining time, and help improve machining accuracy and extend tool life.

[0111] Compared with the prior art, the present invention uses the angle scale of the rotary table in the pre-machining process, which can achieve alignment more quickly while meeting the machining accuracy, thereby improving the machining efficiency.

[0112] Specifically, S206-S207 utilizes the above-mentioned machine tool to process parts, and the tools in S206, S207 and step 4 are selected as carbide tools, which meet the following requirements: diameter 12mm-20mm, chamfer radius 1mm-3mm, and tool speed 800r / min-1500r / min.

[0113] Specifically, the hollow parts can be made of one or more of carbon steel, stainless steel, titanium alloy, aluminum alloy, and aluminum-magnesium alloy.

[0114] Preferably, a heat treatment process of the preformed hollow part blank is also included between the pre-processing process and step 2 to further reduce the residual stress of the pre-processing process, and the following steps are performed in sequence:

[0115] S208: heat treatment at 120±10℃ for 2h~6h, then air cooling to room temperature;

[0116] S209: Treat at -50±5℃ for 1h~3h, and return to room temperature;

[0117] S110: Heat treatment at 120±10℃ for 2h~6h, then air cool or cool in the furnace to room temperature.

[0118] The thermal stress continuously generated in the process of positive temperature-negative temperature-positive temperature is superimposed on the original residual stress, exceeding the yield strength of the material and causing plastic deformation, thereby reducing the original residual stress and further improving the plasticity and machinability of the cylindrical material.

[0119] On the other hand, the present invention discloses a processing mold for a hollow part with uneven wall thickness, such as Figure 1 As shown: it includes an external pressing plate 1, a pull rod 2 and a bottom fixing piece 3, the external pressing plate 1 is located at one end of the pull rod, the bottom fixing piece 3 is located at the other end of the pull rod 2, the external pressing plate 1 and the bottom fixing piece 3 are fixedly connected by the pull rod 2, and a fixing area for clamping and fixing the preformed hollow part blank is provided between the external pressing plate 1 and the bottom fixing piece 3; the external pressing plate 1 is provided with a positioning block 101 parallel to the built-in axial parallel plane of the preformed hollow part blank at one end (i.e., the outer end face) away from the bottom fixing piece 3, and a center hole 102 for the entry and exit of the processing tool 8 is provided in the center of the external pressing plate 1, and the positioning block 101 is arranged in a solid area 103 on the outer peripheral edge of the center hole 102.

[0120] Specifically, Figure 2 As shown, the molded hollow part 4 is a hollow part whose inner side wall is provided with a built-in plane 402 parallel to the axial direction. Figure 3 It is a cross-sectional view of the formed hollow part 4 at the radial section (AA plane) where the center of the built-in plane 402 parallel to the axial direction is located: multiple built-in planes 402 parallel to the axial direction are not parallel to each other. Figure 4It is a cross-sectional view of the raw material blank of the hollow part 4 in the radial section (AA plane): the raw material blank of the hollow part 4 is a cylindrical part with uneven wall thickness.

[0121] like Figure 1 As shown: the inner side wall of the hollow part 4 is provided with a first built-in plane 4021 and a second built-in plane 4022; the first built-in plane 4021 and the second built-in plane 4022 are not parallel to each other.

[0122] The outer end surface of the external pressing plate 1 of the above-mentioned hollow part processing mold is provided with a first positioning block 1011 and a second positioning block 1012 ; the first built-in plane 4021 is parallel to the first positioning block 1011 , and the second built-in plane 4022 is parallel to the second positioning block 1012 .

[0123] There are one or more positioning blocks 101, which correspond one to one with the built-in planes 402' of the target hollow part.

[0124] At the same time, in order to further transfer the processing mold reference to the preformed hollow part blank and improve the fastening degree of the preformed hollow part blank and the mold to prevent relative sliding, such as Figure 3 As shown, the edge solid area 103 is provided with a plurality of first positioning through holes 105; Figure 4 As shown, a second positioning hole 401 is provided on one side where the preformed hollow part blank is connected to the external pressure plate 1; the centers of the two first positioning through holes 105 are taken as reference points, and the line connecting the reference points is taken as the reference line; one end of the first positioning through hole 105 is axially movably connected to the preformed hollow part blank; the radial rotation of the preformed hollow part blank can be locked by matching the positioning pin 106 with the first positioning through hole 105 and the second positioning hole 401 to prevent radial relative sliding, thereby ensuring stability and accuracy during processing.

[0125] Figure 5 The first built-in plane 4021 and the second built-in plane 4022 are shown in the state when the processing is not completed: the side wall of the preformed hollow part blank is provided with a first target plane 4021' and a second target plane 4022'; the first target plane 4021' at the dotted line is obtained after processing Figure 1 The first built-in plane 4021 and the second target plane 4022' at the dotted line are obtained by processing Figure 1 the second built-in plane 4022; the first positioning block 1011 is parallel to the first target plane 4021', and the second positioning block 1012 is parallel to the second target plane 4022'; after parallel transmission, the angle between the first built-in plane 4021 and the second built-in plane 4022 is the same as the angle between the first target plane 4021' and the second target plane 4022'.

[0126] Specifically, Figure 5As shown, since the built-in plane 402' of the target hollow part is axially parallel, its projection along the axis to the end face is a straight line segment; the positioning block 101 is set to be parallel to the projection of the built-in plane 402' of the target hollow part along the axis to the end face.

[0127] During implementation, the positioning block 101 is set to be a long strip and fixed to the outer end face of the external pressure plate 1; the radial cross-section of the positioning block is set to be circular or quadrilateral; according to the principle of parallel transfer, by measuring the horizontal state of the positioning block 101, the horizontal state of the built-in plane of the target hollow part corresponding to the positioning block 101 can be judged more conveniently and accurately; and, since the tool is perpendicular to the horizontal plane, by adjusting the positioning block 101 to a horizontal state, the alignment of the built-in plane of the corresponding target hollow part can be achieved.

[0128] Compared with the prior art, the present invention converts the inclination angle of the built-in plane of the target hollow part relative to the horizontal plane into the angle between the positioning block and the horizontal plane by setting a positioning block parallel to the radial projection of the built-in plane of the target hollow part, wherein the built-in plane of the target hollow part is abstract and invisible before the processing is completed, and the positioning block is concrete and visible. The advantage of this is that the positioning block can be measured and corrected before processing the built-in plane, thereby realizing the correction of the built-in plane of the target hollow part and improving the processing accuracy.

[0129] Furthermore, the positioning block 101 is fixed to the main body of the external pressure plate 1; the ratio of the length to the width or height of the positioning block is greater than 2; when detecting the horizontal state of the positioning block 101, the larger length to width or height ratio of the positioning block is used, which is beneficial to obtain more sensitive signals at both ends of the top of the positioning block, and is beneficial to further improve the alignment accuracy of the positioning block 101 corresponding to the built-in plane.

[0130] Specifically, the angular relationship between the radial projections of multiple positioning blocks is corrected by a photoelectric autocollimator, and the multiple positioning blocks 101 are corrected and positioned on the rotary table; specifically, the external pressure plate 1 is fixed to the rotary table, and based on the angle of the radial projection of the built-in plane of the target hollow part, the rotary table is rotated to determine the installation position of the positioning block.

[0131] In the case of processing multiple axially parallel built-in planes, it is necessary to set multiple positioning blocks 101 on the external pressure plate 1 that are parallel to the projections of the built-in planes on the radial plane; according to the principle of parallel transmission, the angle between the projections of any two axially parallel built-in planes on the radial plane is the same as the angle between the corresponding positioning blocks 101 on the radial plane.

[0132] During implementation, the remaining positioning blocks are set according to the angle with the reference line. It should be noted that: the positioning blocks can be set on multiple parallel lines that meet the angle relationship with the reference line, and there are multiple feasible installation positions for the positioning blocks to translate on the same parallel line. Therefore, it is necessary to select an installation position on the outer side of the external pressure plate 1 where the positioning block can be set without obstacles. The positioning block set at this installation position should not hinder the other structures and functional settings on the same side of the external pressure plate 1. Based on this, the angle of the projection of any positioning block set on the external pressure plate 1 of the present invention on the radial plane is the same as the angle of the projection of the corresponding axially parallel built-in plane on the radial plane; the angular relationship of the positioning blocks set by the above method corresponds to the angle of the projection of the axially parallel built-in plane to be processed on the radial plane, and the angular relationship of the projection of the axially parallel built-in plane obtained after the alignment of the above positioning blocks on the radial plane is consistent with the design expectations.

[0133] Specifically, Figure 1 As shown: the processing tool can freely enter and exit the central hole 102, so it can meet the processing of the interior of the preformed hollow part blank; the outer side of the edge solid area 103 is used to fix the positioning block 1, and the inner side is pressed and connected with the hollow part 4.

[0134] Furthermore, in order to achieve the fastening connection between the bottom fixing piece 3 and the external pressing plate 1, a tie rod mounting hole 104 is provided on the edge of the body of the external pressing plate 1; one end of the tie rod 2 is provided with a thread, and the other end is fixedly connected to the bottom fixing piece 3, and the thread matches the nut. The tie rod mounting hole 104, the tie rod 2 and the nut form a movable connection structure for adjusting the degree of compression of the external pressing plate 1 and the bottom fixing piece 3 on the hollow part 4, such as Figure 1 As shown, the movable connection structure includes: a tie rod mounting hole 104 set on the edge of the body of the external pressing plate 1; a tie rod 2 with a thread at one end and fixedly connected to the bottom fixing member 3 at the other end, and a nut matching the thread; and a press connection with the edge solid area 103 through the nut. The thread setting allows the tie rod 2 to adjust the tightening degree of the bottom fixing member 3 and the external pressing plate 1, and adjust the end face pressing strength of the preformed hollow part blank.

[0135] Preferably, the tie rod mounting holes 104 are centrally symmetrically arranged relative to the center of the external pressure plate 1, and tie rods 2 corresponding to the number of tie rod mounting holes 104 pass through the tie rod mounting holes 104 and are fixedly connected to the edge solid area 103, and force is uniformly applied in all directions relative to the edge solid area 103 and the center of the bottom fixing member 3.

[0136] Specifically, the second positioning hole 401 is a concave hole with one end open, and the positioning pin 106 passes through the first positioning through hole 105 and is fixed to the second positioning hole 401 .

[0137] On the other hand, the present invention discloses a processing device for hollow parts with uneven wall thickness, which, in addition to the above-mentioned processing mold, also includes: a vertical rotary worktable 5, which is fixedly connected to the other end of the bottom fixing member 3 facing away from the external pressure plate 1, and the vertical rotary worktable 5 is movably connected to one side of a machine tool platform 6; the other side of the machine tool platform 6 is movably connected to a machine tool spindle 7, and a processing tool 8 is connected to the end of the machine tool spindle 7 on the side close to the external pressure plate 1.

[0138] During implementation, the processing range of the processing tool 8 is limited to a fixed area on one side relative to the center of the preformed hollow part blank through program control; correspondingly, the rotation angle of the vertical rotary table 5 is adjusted so that different areas of the preformed hollow part blank enter the fixed area where the processing tool 8 is located during processing, thereby realizing processing of different areas of the preformed hollow part blank.

[0139] It should be noted that the control program of the machine tool does not include an identification module for identifying the position of the preformed hollow part blank. Therefore, before processing the preformed hollow part blank to obtain the corresponding built-in plane of the target hollow part, it is necessary to complete the alignment of the built-in plane to be processed of the preformed hollow part blank.

[0140] Compared with the prior art, the present invention completes the transmission of the angular relationship of the radial projection of the built-in plane of the target hollow part to the angular relationship of the corresponding positioning block by setting a positioning block parallel to the radial projection of the built-in plane of the target hollow part, thereby decomposing the built-in plane processing of the target hollow part into two parts: the alignment and positioning of the built-in plane of the target hollow part and the built-in plane processing of the target hollow part; therefore, the present invention does not need to add a positioning function module when designing the processing program. Compared with the prior art, the workpiece to be processed is fixed, and only the cutting tool is used for processing, which reduces the complexity of program design and the stroke of the processing tool, and improves the processing accuracy and reliability.

[0141] In order to illustrate the technical advancement of the present invention, the following embodiments are further disclosed:

[0142] Example 1

[0143] This embodiment discloses a method for processing a hollow part with uneven wall thickness, such as Figure 7 As shown, the following steps are included:

[0144] Step 1: Select two reference points uniquely corresponding to the preformed hollow part blank at the feed end of the processing mold to construct a reference line, and obtain the angle between the radial projection of the built-in plane of the target hollow part and the reference line; the preformed hollow part blank is clamped and fixed inside the processing mold, one end of the processing mold is fixedly connected to the vertical rotary table, and the other end serves as the feed end; the preformed hollow part blank is provided with a positioning and matching connection structure with the processing mold on one side of the feed end, so that the preformed hollow part blank and the processing mold are matched and connected at the reference point, so that the reference line is transferred from the feed end of the processing mold to the preformed hollow part blank, and at the same time, the absolute position relationship of the built-in plane of the target hollow part relative to the part is converted into the angle between the radial projection of the built-in plane of the target hollow part and the reference line.

[0145] Step 2: A positioning block parallel to the built-in plane of the target hollow part is arranged outside the feed end of the processing mold;

[0146] Specifically, one end of the processing mold is fixedly connected to the vertical rotary table, and the other end is used as the feed end. The angle of the positioning block corresponding to the built-in plane of the two target hollow parts is determined according to the angle of the radial projection of the built-in plane of the two target hollow parts, and each positioning block is sequentially set according to the angle of the positioning block;

[0147] Step 3: Based on the positioning block, the preformed hollow part blank fixed on the vertical rotary table is aligned with the built-in plane of the positioning block corresponding to the target hollow part.

[0148] Step 4: Processing the aligned preformed hollow part blank to obtain the built-in plane.

[0149] Specifically, step 1 of setting a positioning block parallel to the built-in plane of the target hollow part includes the following steps:

[0150] S201: The external pressing plate 1 is coaxially fixed to the horizontal rotary table with a set of first positioning through holes 105 which are centrally symmetrical with respect to the geometric center of the external pressing plate 1; the geometric center of the feed end of the processing mold is taken as the origin, the center line of the first positioning through holes 105 at the initial position is taken as the x'-axis and the reference line, and the coordinate axis z'-axis is set perpendicular to the x'-axis direction in the plane of the horizontal rotary table at the initial position, and the perpendicular line passing through the origin and perpendicular to the coordinate axis x'-axis and the z'-axis is taken as the y'-axis;

[0151] S202: As an example, the angle between the first positioning block 1011 and the reference line is 30°; the angle between the second positioning block 1012 and the reference line is 120°; the angle between the third positioning block and the reference line is 240°; the angle between the fourth positioning block and the reference line is 320°; the polyhedron is rotated from the initial position by α 1 ' degrees, set the first positioning block; rotate the polyhedron from the initial position in sequence α 2 '、α3 '、α 4 ', set the second positioning block, the third positioning block, and the fourth positioning block in sequence.

[0152] Furthermore, in order to improve the positioning accuracy of the positioning block on the external pressure plate 1, it is necessary to calibrate the rotation accuracy of the polyhedron when it rotates α degrees in S202, which includes the following steps:

[0153] S2021: setting the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; adjusting the angle of the photoelectric autocollimator relative to the x' axis so that the reading of the photoelectric autocollimator on the optional reflective surface of the polyhedron is 0, fixing the photoelectric autocollimator as the initial position of the polyhedron, and fixing the photoelectric autocollimator;

[0154] S2022: For the second positioning block 1012, the number of reflecting surfaces N of the polyhedron satisfies N=k×360 / α=3k, where k is a positive integer. Therefore, considering the difficulty and cost of processing the polyhedron, a trihedron, a hexahedron, a pentahedron, a dodecahedron, a pentadecahedron and an octahedron can be selected; the polyhedron is rotated through k reflecting surfaces (the corresponding k values ​​for the trihedron, the hexahedron, the pentahedron, the dodecahedron, the pentadecahedron and the octadecahedron are 1, 2, 3, 4, 5, 6), the rotation angle of the polyhedron is fine-tuned so that the reading of the photoelectric autocollimator is 0, the rotation angle of the polyhedron is fixed, and the second positioning block calibration is completed; the third positioning block and the fourth positioning block calibration are completed in the same way.

[0155] Furthermore, in order to improve the accuracy of the positioning block timing, step 3 includes using a dial indicator to calibrate the positioning block position, which specifically includes the following steps:

[0156] S301: adjusting the rotation angle of the horizontal rotary table, and setting the positioning block approximately horizontally by visual judgment;

[0157] S302: Install a dial indicator on the machine tool spindle and move the spindle left and right along the projection line of the radial plane of the preformed hollow part blank on the horizontal plane, and fine-tune the angle of the positioning block according to the percentage indication until the dial indicator pointer indication changes by less than 1% when the dial indicator needle slides from one end to the other end on the positioning block, and the positioning block is determined to be strictly horizontal.

[0158] The ratio of the length to the width or height of the positioning block is set to 5; increasing the ratio of the length to the width or height of the positioning block is conducive to obtaining a larger height difference at both ends of the top of the positioning block, so that the dial indicator has a larger indication change and obtains a more sensitive signal.

[0159] The process between step 2 and step 3 also includes pre-processing the preformed hollow part blank;

[0160] Specifically, the pre-processing process of the preformed hollow part blank includes the following steps:

[0161] S204: Select a group of first positioning through holes 105 that are centrally symmetrical, use the center line of the two as the reference line of the first positioning block, and obtain the angle α between the reference line and the first positioning block. 0 ;

[0162] S205: Fix the preformed hollow part blank on the rotary table through the processing mold, and obtain the inclination angle α between the reference line and the horizontal plane - , based on the angle α 0 and angle α - Get the rotary table rotation angle α required for the first positioning block to align t1 ; Based on α t1 Complete the preliminary alignment of the first built-in plane; specifically, α t1 Satisfaction: α t1 =α - +90°-α 0 ;

[0163] S206: Processing the mold to be processed after the preliminary alignment of the first built-in plane is completed with a 0.2 mm margin;

[0164] S207: Based on alpha t1 and the angle α between the first built-in plane and the second built-in plane 1 Get the rotary table rotation angle α required for the second positioning block to align t2 , based on α t1 The angle α between the first built-in plane and the third built-in plane 2 Get the rotary table rotation angle α required for the third positioning block to align t3 , ..., based on α t and the angle α between the Nth built-in plane and the first built-in plane N Get the rotary table rotation angle α required for the Nth positioning block to align tN Specifically, the Nth positioning block aligns the required rotary table rotation angle α tN , satisfying: α tN =α t1 +α N ; Based on α t2 , …, α tN The second built-in plane, ..., the Nth built-in plane are preliminarily aligned; the preformed hollow part blank that has completed the preliminarily aligned second built-in plane, ..., the Nth built-in plane is processed with a 0.2mm margin.

[0165] Preferably, in order to ensure positioning accuracy, the angle α between the reference line and the first positioning block is obtained by a photoelectric autocollimator. 0 .

[0166] This embodiment sets up a pre-machining process and performs pre-machining under the premise of meeting the accuracy requirements, thereby improving the problems of reference drift, tool overheating and raw material aging and deformation caused by too long finishing time, which helps to improve machining accuracy and extend tool life.

[0167] The present invention provides a pre-machining process for the built-in plane of the target hollow part before fine machining, which can remove the raw material surplus designed in the preformed hollow part blank, reduce the burden of the tool during precise machining, avoid tool overheating and raw material aging problems caused by too long fine machining time, and help improve machining accuracy and extend tool life.

[0168] Compared with the prior art, the present invention uses the angle scale of the rotary table in the pre-machining process, which can achieve alignment more quickly while meeting the machining accuracy, thereby improving the machining efficiency.

[0169] Specifically, the tool used for processing in S206 and step 3 is a carbide tool that meets the following requirements: diameter 16 mm, chamfer radius 2 mm, and tool speed 1000 r / min.

[0170] Specifically, the hollow part is made of titanium alloy.

[0171] Preferably, a heat treatment process of the preformed hollow part blank is also included between the pre-processing process and step 3 to further reduce the residual stress of the pre-processing process, and the following steps are performed in sequence:

[0172] S208: heat treatment at 120°C for 6 hours, followed by air cooling to room temperature;

[0173] S209: Treat at -50°C for 2 hours, and return to room temperature;

[0174] S210: Heat treatment at 120℃ for 6h, then air cooling or furnace cooling to room temperature.

[0175] Specifically, step 4 and S206-S207 use a machine tool to process parts, including the following steps:

[0176] S401: Using the x, y, z three-axis spatial coordinate system set by the machine tool itself, wherein the x-axis is set parallel to the horizontal plane, the y-axis is set parallel to the axial direction of the processed part, and the z-axis is set perpendicular to the horizontal plane, a three-dimensional model of the preformed hollow part blank and a three-dimensional model of the processed part finished product are constructed;

[0177] S402: The programming software compares the three-dimensional model of the preformed hollow part blank with the three-dimensional model of the finished part to obtain the area to be processed F (x, y, z), and generates a processing program;

[0178] S403: Processing the aligned part from inside to outside based on the processing program to obtain a finished part with a corresponding built-in plane.

[0179] Example 2

[0180] This embodiment discloses a method for positioning a hollow part with an axially parallel plane. Figure 8 As shown, it includes steps 1 to 3 of embodiment 1 and all steps S201-S110, S2011-S2012, S2021-S2022, S301-S302 and specific implementation methods. In this embodiment, by setting a positioning block parallel to the built-in plane of the target hollow part, the angle relationship of the built-in plane of the target hollow part projected on the radial plane is converted into the angle relationship between the positioning blocks, so as to achieve the relative position relationship positioning between the built-in planes of the target hollow part; at the same time, the inclination angle of the built-in plane of the target hollow part relative to the horizontal plane is converted into the angle between the positioning block and the horizontal plane, and the built-in plane of the target hollow part is aligned by confirming the position of the positioning block, thereby achieving the absolute position relationship positioning of the built-in plane of the target hollow part relative to the horizontal plane.

[0181] Example 3

[0182] This embodiment discloses a processing mold for a hollow part with uneven wall thickness, which is used in the above processing method, such as Figure 1 As shown: an external pressing plate 1 is provided at one axial end of the processing mold, and a bottom fixing piece 3 is provided at the other end; a fixing area for clamping and fixing a hollow part 4 is provided between the external pressing plate 1 and the bottom fixing piece 3 and is fixedly connected by a pull rod 2; a positioning block 101 parallel to the built-in plane of the target hollow part is provided on the side of the external pressing plate 1 away from the bottom fixing piece 3.

[0183] Figure 2 A 45° top view of a molded hollow part is shown; Figure 3 The cross-sectional scene of the radial section (AA plane) where the center of the axially parallel built-in plane 402 is located is shown; Figure 2 and Figure 3 As shown, a plurality of axially parallel built-in planes 402 are not parallel to each other. Figure 4 FIG. 4 shows a cross-sectional view of a raw material blank of a hollow part 4 in a radial cross section (AA plane), as shown in FIG. Figure 3 and Figure 4 As shown: the hollow part 4 is obtained by machining the part body 403 from the inside to the outside.

[0184] like Figure 5As shown: the positioning block 101 is a rectangular parallelepiped, which is fixed to the external pressure plate 1 through the axial side surface; by measuring the horizontal state of the positioning block 101, the horizontal state of the built-in plane of the target hollow part corresponding to the positioning block 101 can be judged more conveniently and accurately; by adjusting the positioning block 101 to be horizontal, the built-in plane of the corresponding target hollow part can be aligned; at the same time, the positioning block can be measured and corrected before processing the built-in plane, so as to realize the correction of the built-in plane of the target hollow part and improve the processing accuracy.

[0185] like Figure 5 As shown: there are four positioning blocks 101 with the same size, and the ratio of the length to the width or height of the positioning blocks is 5; a larger ratio of the length to the width or height is conducive to obtaining more sensitive signals at both ends of the top of the positioning block, which is conducive to further improving the alignment accuracy of the positioning block corresponding to the built-in plane.

[0186] At the same time, multiple positioning blocks are corrected for the angular relationship between their radial projections through a photoelectric autocollimator, and multiple positioning blocks 101 are corrected and positioned on the external pressure plate 1 through a rotary worktable; for multiple axially parallel built-in planes to be processed, it is necessary to set positioning blocks 101 on the external pressure plate 1 that are parallel to the projections of the built-in planes on the radial plane; according to the parallel transmission principle, the angle between the projections of any two built-in planes on the radial plane is the same as the angle between the corresponding positioning blocks 101.

[0187] like Figure 1 As shown, the outer pressure plate 1 is provided with an edge solid area 103 on the periphery of the central hole 102, and the edge solid area 103 is provided with a tie rod mounting hole 104 which is centrally symmetrical with respect to the center of the outer pressure plate 1; at the same time, the tie rod 2 is provided with a thread, and is pressed and connected with the edge solid area 103 through a nut, so as to realize the fastening connection between the bottom fixing part 3 and the outer pressure plate 1. Multiple tie rods 2 are fixedly connected with the edge solid area 103 through the tie rod mounting holes 104, and force is uniformly applied in all directions relative to the edge solid area 103 and the center of the bottom fixing part 3.

[0188] like Figure 3 As shown, the edge solid area 103 is provided with a plurality of first positioning through holes 105; Figure 4 As shown, a second positioning hole 401 is provided on one side where the hollow part 4 is connected to the external pressure plate 1; the positioning pin 106 is matched and connected with the first positioning through hole 105 and the second positioning hole 401 to prevent radial relative sliding, thereby ensuring stability and accuracy during processing; at the same time, the centers of the two first positioning through holes 105 are used as reference points, and the line connecting the reference points is used as the reference line to transfer the processing mold reference to the preformed hollow part blank.

[0189] The second positioning hole 401 is a concave hole with one end open. The positioning pin 106 passes through the first positioning through hole 105 and is fixed to the second positioning hole 401 .

[0190] Example 4

[0191] This embodiment discloses a processing device for a hollow part with uneven wall thickness, comprising the processing mold described in Embodiment 3, and used in the above processing method, such as Figure 6 As shown, it also includes: a vertical rotary worktable 5, one end of the vertical rotary worktable 5 is fixedly connected to the other end of the bottom fixing member 3 facing away from the external pressure plate 1, and the other end of the vertical rotary worktable 5 is movably connected to one side of a machine tool platform 6; the other side of the machine tool platform 6 is movably connected to a machine tool spindle 7, and the end of the machine tool spindle 7 close to the external pressure plate 1 is connected to a machining tool 8.

[0192] During implementation, a central hole 102 for the entry and exit of the processing tool 8 is provided in the center of the external pressure plate 1; the processing range of the processing tool 8 is limited to a fixed area on one side relative to the center of the hollow part 4 through program control; correspondingly, the rotation angle of the vertical rotary table 5 is adjusted so that different areas of the hollow part 4 enter the fixed area where the processing tool 8 is located during processing, thereby meeting the processing of different areas of the hollow part 4.

[0193] It should be noted that the control program of the machine tool does not include a module for identifying the position of the hollow part 4 , and therefore, before processing the hollow part 4 to obtain the corresponding built-in plane to be processed, the built-in plane to be processed of the hollow part 4 needs to be aligned.

[0194] As an example, Figure 6 As shown, the processing range of the processing tool 8 is limited to the bottom area of ​​the hollow part 4 through program control; the rotation angle of the rotary table 5 relative to the machine tool platform 6 is adjusted to the level of the first positioning block 1011 to achieve the alignment of the first target plane 4021', and at the same time, the first target plane 4021' is placed within the processing range 405 of the processing tool 8.

[0195] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. Processing method of hollow parts with uneven wall thickness, It is characterized in that The following steps are involved: At least two reference points uniquely corresponding to the preformed hollow part blank are selected at the feed end of the processing mold to construct a reference line, and the angle between the radial projection of the built-in plane of the target hollow part and the reference line is obtained; Based on the angle between the radial projection of the built-in plane of the target hollow part and the reference line, a positioning block parallel to the built-in plane of the target hollow part is arranged outside the feed end of the processing mold; Based on the positioning block, the preformed hollow part blank is aligned on the built-in plane of the positioning block corresponding to the target hollow part; Processing the aligned preformed hollow part blank to obtain the built-in plane; Rotate the polyhedron by α based on the central angle of the circle corresponding to the reflection surface of the polyhedron M ', set the positioning block; where α M ' is the angle between the Mth positioning block and the reference line; The preformed hollow part blank is clamped and fixed inside the processing mold, one end of the processing mold is fixedly connected to the vertical rotary table, and the other end is used as the feed end; the preformed hollow part blank is provided with a positioning and matching connection structure with the processing mold on one side of the feed end, so that the preformed hollow part blank and the processing mold are matched and connected at the reference point; A polyhedral prism is coaxially fixed in the center area of ​​the horizontal rotary table; Setting the positioning block includes: Setting the positioning block parallel to the built-in plane of the target hollow part: The optional static position after the processing mold is installed on the horizontal rotary table is taken as the initial position, the geometric center of the outer side surface of the feed end of the processing mold is taken as the origin, the coordinate axis x' axis is set in the direction parallel to the reference line at the initial position, the coordinate axis z' axis is set in the radial plane of the processing mold and is perpendicular to the coordinate axis x' axis, and the y' axis is set in the direction of the perpendicular line passing through the origin and perpendicular to the coordinate axis x' axis and the z' axis, so as to construct the x'y'z' three-axis coordinate system; Get the angle α between the Mth positioning block and the reference line M '; Rotate the polyhedron from its initial position by α M ', set the Mth positioning block in the x'z' plane; M is a positive integer.

2. The processing method according to claim 1, It is characterized in that The positioning of the reference point includes: matching and connecting the preformed hollow part blank with the processing mold at the reference point, and positioning the reference point.

3. The processing method according to claim 2, It is characterized in that The matching connection at the reference point includes: preforming the hollow part blank through positioning pins and matching the connection with the processing mold.

4. The processing method according to claim 1, It is characterized in that Polyhedron rotation α M ', including: correcting the rotation angle of the polyhedral prism through a photoelectric autocollimator.

5. The processing method according to claim 4, It is characterized in that Correction of the rotation angle of the polyhedron, including: Polyhedron rotation α M ', set the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; adjust the angle of the photoelectric autocollimator relative to the x' axis so that the reading of the photoelectric autocollimator on the optional reflective surface of the polyhedral prism is 0, and fix the photoelectric autocollimator as the initial position of the polyhedral prism; Rotate the polyhedron by k reflecting surfaces, fine-tune the rotation angle of the polyhedron so that the reading of the photoelectric autocollimator is 0, and fix the polyhedron to complete the calibration; where k satisfies: k = α M '×N / 360, α M ' is the angle between the Mth positioning block and the reference line, k is a positive integer, and N is the number of reflecting surfaces of the polyhedral prism.

6. The processing method according to claim 1, It is characterized in that Between the pre-machining process and the alignment of the built-in plane, a heat treatment process for the preformed hollow part blank is also included.

7. The processing method according to claim 6, It is characterized in that The heat treatment of the preformed hollow part blank comprises the following steps: Heat treatment at 120±10℃ for 2h~6h, then air cool to room temperature; Treat at -50±5℃ for 1h~3h, then return to room temperature; Heat treat at 120±10℃ for 2h~6h, then air cool or cool in the furnace to room temperature.

8. The processing method according to claim 1, It is characterized in that The machining program of the built-in plane is obtained, which is generated by machining programming software based on the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the finished machined part.

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