Positioning method of built-in axial parallel plane of hollow parts

Abstract

This invention relates to the field of mechanical manufacturing technology, and in particular to a method for positioning the internal axial parallel plane of a hollow part. The method includes: setting a positioning block parallel to the internal plane of the target hollow part on the outer side of the machining mold's feed end, based on a polyhedron rotating coaxially with the machining mold; and aligning the pre-formed hollow part blank to the internal plane of the target hollow part corresponding to the positioning block. This invention achieves visual positioning and correction of the plane to be machined by setting a positioning block parallel to the radial projection of the internal plane; and further improves the positioning accuracy of the internal plane by optimizing the positioning accuracy of the positioning block using a photoelectric autocollimator.

Description

Technical Field

[0001] The invention relates to the technical field of metal material manufacturing, and in particular to a positioning method for a built-in axial parallel plane of a hollow part. 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, a common processing method is to 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 long tool stroke, complex correction and program control; another common processing method is to 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 turn 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°. Further improving the processing accuracy is mainly restricted by the positioning accuracy of the built-in plane. At present, the market is in urgent need of a positioning method for the built-in planes parallel to the axis in high-precision hollow parts. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a method for positioning the built-in axial parallel plane of a hollow part, so as to solve the problem of poor positioning accuracy of the built-in axial parallel plane of a hollow part by a lathe in the prior art.

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

[0006] The present invention provides a method for positioning a built-in axial parallel plane of a hollow part, comprising:

[0007] Based on a polyhedral prism that rotates coaxially with the processing mold, a positioning block parallel to the built-in plane of the target hollow part is arranged outside the feed end of the processing mold;

[0008] 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.

[0009] Preferably, a positioning block parallel to the built-in plane of the target hollow part is set, including: confirming the angle of the positioning block corresponding to the parallel built-in plane of the two target hollow parts according to the angle of the radial projection of the built-in plane of the two target hollow parts, and setting each positioning block in sequence according to the angle of the positioning block.

[0010] Preferably, setting a positioning block parallel to the built-in plane of the target hollow part comprises the following steps:

[0011] Taking the geometric center of the outer side surface of the feed end of the processing mold as the origin and the radial plane of the processing mold as the x'z' plane, construct an x'y'z' three-axis coordinate system, and set a first positioning block as a reference positioning block in the x'z' plane;

[0012] Obtain an included angle α between the first positioning block and the second positioning block, and fix a polyhedron in the central area of ​​the horizontal rotary table; rotate the polyhedron by α degrees, and set a second positioning block in an area in the x'z' plane, wherein the included angles of the second positioning block with the x' axis and the z' axis are the same as those of the first positioning block;

[0013] Based on the angle between the first positioning block and the Mth positioning block, the polyhedron is rotated by the angle between the first positioning block and the Mth positioning block to set the Mth positioning block; M is a positive integer greater than or equal to 3.

[0014] Preferably, setting the Mth positioning block includes correcting the positioning accuracy of the positioning block using a dial indicator.

[0015] Preferably, the positioning accuracy of the positioning block is corrected using a dial indicator, comprising the following steps:

[0016] Set the positioning block vertically in the z' axis direction;

[0017] Set up a dial indicator on the machine tool spindle and let the spindle translate along the x-axis, and fine-tune the angle between the positioning block and the z' axis according to the indication, until the dial indicator pointer changes below the threshold when the dial indicator needle slides from one end to the other on the positioning block, and it is determined that the positioning block is strictly perpendicular to the z' axis direction.

[0018] Preferably, rotating the polyhedron by α degrees includes approximately rotating the polyhedron by α degrees based on the central angle corresponding to the reflecting surface of the polyhedron, and correcting the rotation angle of the polyhedron by a photoelectric autocollimator.

[0019] Preferably, the polyhedral prism rotation angle correction is performed by a photoelectric autocollimator, comprising the following steps:

[0020] Set the plane where the photoelectric autocollimator is parallel to the coordinate axes x' and z', select the position of the polyhedron before the polyhedron is rotated α degrees as the initial position, adjust the angle of the photoelectric autocollimator relative to the x' axis, so that the reading of the photoelectric autocollimator on any optional reflective surface of the polyhedron is 0, and fix the photoelectric autocollimator;

[0021] The polyhedron is rotated by k reflecting surfaces, the rotation angle of the polyhedron is fine-tuned to make the reading of the photoelectric autocollimator 0, and the polyhedron is fixed to complete the correction; wherein k satisfies: k=α×N / 360, k is a positive integer, and N is the number of reflecting surfaces of the polyhedron.

[0022] Preferably, the alignment of the built-in plane of the target hollow part includes correcting the positioning accuracy of the positioning block using a dial indicator.

[0023] Preferably, the positioning accuracy of the positioning block is corrected using a dial indicator, comprising the following steps:

[0024] Adjust the rotation angle of the horizontal rotary table to which the positioning block is fixedly connected, and set the positioning block approximately horizontally;

[0025] A dial indicator is mounted on the main spindle of the machine tool, and the main spindle of the machine tool is moved in the direction of the projection line of the radial plane parallel to the preformed hollow part blank on the horizontal plane, and the angle of the positioning block is fine-tuned according to the indication of the dial indicator pointer, until the dial indicator pointer indication 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. Preferably, the change in the dial indicator pointer indication η satisfies: η=S max -S min , the threshold is 1%.

[0026] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0027] (1) 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.

[0028] (2) The present invention converts the alignment of the built-in plane of the target hollow part 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 built-in plane of the target hollow part can be corrected by measuring and correcting the positioning blocks, thereby improving the processing accuracy.

[0029] (3) 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, which reduces 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.

[0030] (4) The present invention sets a positioning block parallel to the radial projection of the built-in axial parallel plane to be processed, and uses the parallel transfer 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.

[0031] 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

[0032] 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.

[0033] Figure 1 This is a schematic diagram of a hollow part with a built-in axially parallel plane and a processing mold assembled from a 45° top view in one embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of a 45° top view of a hollow part with a formed built-in axially parallel plane in one embodiment of the present invention;

[0035] Figure 3 It is a cross-sectional view of the AA surface of a hollow part with a built-in axial parallel plane in one embodiment of the present invention;

[0036] Figure 4 It is a cross-sectional view of the AA surface of a hollow part blank with a built-in axial parallel plane in one embodiment of the present invention;

[0037] Figure 5 It is a schematic diagram of the assembly of a hollow part with an unformed built-in axial parallel plane, an external pressing plate and a positioning block from a 45° top view in one embodiment of the present invention;

[0038] Figure 6A schematic diagram of a processing device and an installation method of a hollow part with a built-in axially parallel plane in one embodiment of the present invention;

[0039] Figure 7 This is a flow chart of a method for processing a hollow part with a built-in axially parallel plane in one embodiment of the present invention;

[0040] Figure 8 The present invention is a flowchart of a method for positioning a built-in axial parallel plane of a hollow part in one embodiment of the present invention.

[0041] Reference numerals:

[0042] 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 plane to be processed 4021'; second plane to be processed 4022'; part body 403; processing range 405 of processing tool. DETAILED DESCRIPTION

[0043] 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.

[0044] In order to clearly explain the technical solution of the present invention, the following technical terms are further defined:

[0045] Alignment:

[0046] The present invention defines alignment as a state in which the plane to be processed is parallel to the horizontal plane.

[0047] The angle between the straight line l1 and the straight line l2 is:

[0048] The angle by which line l1 is rotated counterclockwise until it becomes parallel to line l2.

[0049] 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.

[0050] The present invention provides a positioning method for a hollow part with a built-in axial parallel plane, such as Figure 8 As shown, the following steps are included:

[0051] Step 1: Based on a polyhedron that rotates coaxially with the processing mold, 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;

[0052] Specifically, one end of the processing mold is fixedly connected to the vertical rotary worktable, and the other end serves as a 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 arranged in sequence according to the angle of the positioning block; a polyhedron rotating coaxially with the processing mold is provided on one side of the feed end of the processing mold, and the polyhedron is provided with reflective side surfaces arranged in continuous vertical and horizontal planes. Every time a reflective side surface is rotated, the polyhedron rotates by an angle of 360 / N degrees; wherein N is the number of reflective surfaces of the polyhedron.

[0053] Specifically, Figure 1 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.

[0054] During implementation, the first positioning block 1011 is set as a reference positioning block, and the positioning blocks are set according to the angles of the remaining positioning blocks relative to the reference positioning block.

[0055] It should be noted that: there are multiple installation positions for the positioning block that meets 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 any two positioning blocks set on the external pressure plate 1 of the present invention is the same as the angle between the projections of the corresponding built-in planes on the radial plane; the angular relationship of the positioning blocks set by the above method corresponds to the angle between the projections 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.

[0056] Step 2: 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;

[0057] 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.

[0058] 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 using the positioning block for alignment in the present invention is that compared with the prior art, the present invention converts the alignment of the built-in plane of the target hollow part into the horizontal adjustment of the corresponding positioning block, and 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.

[0059] Specifically, the step 1 of setting a positioning block parallel to the built-in plane of the target hollow part on the outer side of the feed end of the processing mold includes the following steps:

[0060] S101: Taking the geometric center of the outer side surface of the feed end of the processing mold as the origin and the radial plane of the processing mold as the x'z' plane, constructing an x'y'z' three-axis coordinate system, and setting a first positioning block 1011 as a reference positioning block in the x'z' plane;

[0061] Specifically, the external pressing plate 1 is coaxially fixed to the horizontal rotary table with a group of first positioning through holes 105 that are centrally symmetrical relative to the geometric center of the external pressing plate 1; the geometric center of the outer side surface 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 coordinate axis z' axis is set in the plane of the horizontal rotary table at the initial position perpendicular to the x' axis direction, and the perpendicular line passing through the origin perpendicular to the coordinate axis x' axis and the z' axis is taken as the y' axis; the first positioning block 1011 is set in the solid area outside the external pressing plate 1 perpendicular to the z' axis direction;

[0062] S102: Obtain the included angle α between the first positioning block 1011 and the second positioning block 1012, and a polyhedron is fixedly provided in the central area of ​​the horizontal rotary table; rotate the polyhedron by α degrees, and set the second positioning block 1012 in the x'z' plane, wherein the included angles between the second positioning block 1012 and the x' axis and the z' axis are the same as those of the first positioning block 1011; specifically, set the second positioning block 1012 in the solid area outside the external pressing plate 1 perpendicular to the z' axis direction;

[0063] S103: Based on the angle between the first positioning block and the Mth positioning block, rotate the polyhedron by the angle between the first positioning block and the Mth positioning block to set the Mth positioning block; M is a positive integer greater than or equal to 3.

[0064] It should be noted that S101-S103 are implemented on a horizontal rotary table, which is different from the vertical rotary table described in steps 1-3: the rotation plane of the horizontal rotary table is set horizontally, and it is the worktable of the horizontal machining center; the rotation plane of the vertical rotary table is set vertically to the horizontal plane.

[0065] It should be noted that in order to ensure the consistent angle relationship relative to the first positioning block, the second positioning block, the third positioning block, ..., the Mth positioning block are provided in S102 and S103, and the polyhedrons rotate in the same direction.

[0066] Specifically, in order to correct the positioning accuracy of the positioning block in the direction perpendicular to the z'-axis, a first positioning block 1011 is set in the direction perpendicular to the z'-axis in S101, a second positioning block 1012 is set in the direction perpendicular to the z'-axis in S102, and a third positioning block is set in S103, ..., the Mth positioning block, including using a dial indicator to correct the positioning accuracy of the positioning block in the direction perpendicular to the z-axis.

[0067] Specifically, the following steps are included:

[0068] S1011: Setting the positioning block perpendicular to the z' axis direction;

[0069] S1012: Install a dial indicator on the machine tool spindle and allow the spindle to translate along the x' axis, and fine-tune the angle of the positioning block according to the indication until the dial indicator pointer indication changes below the threshold when the dial indicator needle slides from one end to the other end on the positioning block, and determines that the positioning block is strictly perpendicular to the z' axis direction.

[0070] It should be noted that in S1011, the positioning block can be set perpendicular to the z'-axis 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.

[0071] During implementation, in S1012, by installing a dial indicator on the machine tool spindle, parallel movement along the x' axis of the dial indicator coordinate axis can be achieved, and the dial indicator displacement probe contacts the side surface to be measured of the positioning block; if the side surface to be measured is not parallel to the x' axis of the coordinate axis, the dial indicator displacement probe has a displacement change on the side surface to be measured, resulting in a change in the percentage indication number; if the side surface to be measured is parallel to the x' axis of the coordinate axis, the change in the percentage indication number cannot be detected or is 0.

[0072] Specifically, the side surface to be measured is: the side surface of the positioning block parallel to the coordinate axis y' axis.

[0073] Specifically, the change in the dial indicator pointer reading is introduced to evaluate the parallelism between the side to be measured and the coordinate axis x': if η is less than 1%, it is judged that the alignment is completed; the change in reading 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.

[0074] Specifically, in S102, the angle between the first positioning block 1011 and the second positioning block 1012 is the same as the angle between the projections of the first plane to be processed 4021' and the second plane to be processed 4022' on the radial plane; wherein, the first plane to be processed 4021' is parallel to the first positioning block 1011; and the second plane to be processed 4022' is parallel to the second positioning block 1012.

[0075] Specifically, the polyhedron is rotated by α degrees in S102, which includes precision correction of the rotation angle of the polyhedron by a photoelectric autocollimator.

[0076] 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.

[0077] Specifically, in S102, the side surface of the polyhedron is a rectangular reflective surface with the same size as the vertical horizontal surface.

[0078] Specifically, the number of faces N of the polyhedron in S102 needs to be selected based on k=α / (360 / N), where k is a positive integer; wherein 360 / N is the center angle corresponding to a single reflection surface of the polyhedron, and in order to match the correction of the reflection surface of the polyhedron by the photoelectric autocollimator, the rotation of the polyhedron is based on the center angle corresponding to the single reflection surface as a basic unit rotation; in the case of less than one basic unit (k is not an integer), the value of N should be adjusted to satisfy k taking a positive integer, and the number of reflection surfaces of the polyhedron is determined to obtain a suitable polyhedron.

[0079] Specifically, in S102 , the polyhedron is rotated by α degrees, the polyhedron is approximately rotated by α degrees based on the central angle corresponding to the reflection surface of the polyhedron, and the rotation angle of the polyhedron is corrected by a photoelectric autocollimator.

[0080] Specifically, the following steps are included:

[0081] S1021: setting the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; selecting the position of the polyhedron before the polyhedron is rotated α degrees as the initial position, adjusting the angle of the photoelectric autocollimator relative to the x' axis so that the reading of the photoelectric autocollimator on any optional reflective surface of the polyhedron is 0, and fixing the photoelectric autocollimator;

[0082] S1022: Rotate the polyhedron by k reflective surfaces, fine-tune the rotating workbench in the bedroom, adjust the rotation angle of the polyhedron so that the reading of the photoelectric autocollimator is 0, and fix the polyhedron to complete the calibration; wherein, k satisfies: k=α×N / 360, k is a positive integer, and N is the number of reflective surfaces of the polyhedron.

[0083] It should be noted that when the reading of the photoelectric autocollimator in S1022 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 the rotation of the preformed hollow part blank along the axis, adjusting the positioning block to be 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 2 includes using a dial indicator to calibrate the positioning block position, which specifically includes the following steps:

[0087] S201: 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] S202: A dial indicator is mounted on the machine tool spindle, and the machine tool spindle is moved in the direction of the projection line of the radial plane parallel to the preformed hollow part blank on the horizontal plane, and the worktable angle is fine-tuned according to the number indicated by the dial indicator pointer and the angle of the positioning block is driven to change, 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 S201, 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 spindle of the machine tool, parallel movement along the radial plane on the horizontal plane projection line 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; if the indication change 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] 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.

[0095] Preferably, a pre-processing process of the preformed hollow part blank is also included between step 1 and step 2 to further improve the above technical problems, including the following steps:

[0096] S104: Establishing a reference line, obtaining an angle α0 between the reference line and the first positioning block; specifically, selecting a group of centrosymmetric first positioning through holes 105, taking the center line connecting the two as the reference line of the first positioning block, and obtaining an angle α0 between the reference line and the first positioning block;

[0097] S105: 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 α0 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°-α0;

[0098] S106: 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;

[0099] S107: Based on alpha t1 The angle α1 between the first built-in plane and the second built-in plane is used to obtain the rotary table rotation angle α required for the second positioning block to align t2 , based on α t1 The angle α2 between the first built-in plane and the third built-in plane is used to obtain the rotation angle α of the rotary table 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 planeN 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.

[0100] Preferably, in order to ensure positioning accuracy, the angle α0 between the reference line and the first positioning block is obtained by a photoelectric autocollimator.

[0101] 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.

[0102] 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.

[0103] Specifically, S106-S107 utilizes the above-mentioned machine tool to process parts, and the tool in S106 and S107 is a carbide tool that meets the following requirements: diameter 12mm-20mm, chamfer radius 1mm-3mm, and tool speed 800r / min-1500r / min.

[0104] Specifically, the hollow parts can be made of one or more of carbon steel, stainless steel, titanium alloy, aluminum alloy, and aluminum-magnesium alloy.

[0105] 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:

[0106] S108: heat treatment at 120±10℃ for 2h~6h, then air cooling to room temperature;

[0107] S109: Treat at -50±5℃ for 1h~3h, then let it warm up at room temperature;

[0108] S110: Heat treatment at 120±10℃ for 2h~6h, then air cool or cool in the furnace to room temperature.

[0109] 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.

[0110] On the other hand, the present invention discloses a method for processing a hollow part with a built-in axially parallel plane, which, in addition to the above steps, also includes step 3 of processing the preformed hollow part blank after alignment 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.

[0111] Optionally, the machining program in step 3 may be generated by machining programming software based on the three-dimensional models of the preformed hollow part blank and the machined part product.

[0112] 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 z-axis is set parallel to the axial direction of the processed part, and the y-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.

[0113] 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.

[0114] The machining error of the tool is proportional to its stroke. Compared with the prior art, the present invention adopts a rotating method of the preformed hollow part blank to realize the machining 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 machining stroke. Compared with the prior art processing method in which the processed parts are fixed and the tool is moved to each processing area, the cumulative error of the tool caused by the increase in stroke is reduced, and the accuracy is improved.

[0115] 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.

[0116] Specifically, step 3 of machining parts using a machine tool includes the following steps:

[0117] S301: constructing a three-dimensional model of a preformed hollow part blank and a three-dimensional model of a processed part finished product in a programming software;

[0118] S302: 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;

[0119] S303: The machine tool processes the aligned part based on the processing program to obtain a finished part with a corresponding built-in plane.

[0120] Specifically, in S301, 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 S302, 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.

[0121] In step 3, a carbide tool is selected as the tool, which meets the following requirements: diameter 12mm to 20mm, chamfer radius 1mm to 3mm, and tool speed 800r / min to 1500r / min.

[0122] On the other hand, the present invention discloses a processing mold for a hollow part with an axially parallel plane built in, 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 hollow part has a built-in axial parallel plane, and the end of the external pressing plate 1 away from the bottom fixing piece 3 (i.e., the outer end face) is provided with a positioning block 101 parallel to the built-in axial parallel plane of the preformed hollow part blank, and a central 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 central hole 102.

[0123] 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 4 It 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 centrally symmetrical cylindrical part.

[0124] 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.

[0125] The outer end surface of the outer 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 positioning block 1011 is parallel to the first built-in plane 4021 , and the second positioning block 1012 is parallel to the second built-in plane 4022 .

[0126] There are one or more positioning blocks 101, which correspond one to one with the built-in planes 402' of the target hollow part.

[0127] Figure 5 The first built-in plane 4021 and the second built-in plane 4022 are shown in the state where the processing is not completed: the side wall of the preformed hollow part blank is provided with a first plane to be processed 4021' and a second plane to be processed 4022'; the first plane to be processed 4021' at the dotted line is processed to obtain Figure 1 The first built-in plane 4021 and the second plane to be processed 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 plane to be processed 4021', and the second positioning block 1012 is parallel to the second plane to be processed 4022'; after parallel transfer, 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 plane to be processed 4021' and the second plane to be processed 4022'.

[0128] Specifically, Figure 5 As 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 on the radial plane.

[0129] 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,, 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 the horizontal, the alignment of the built-in plane of the corresponding target hollow part can be achieved.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] During implementation, the first positioning block 101 is set as the reference positioning block, and the remaining positioning blocks are set according to the angle with the reference positioning block. It should be noted that the positioning block can be set on multiple parallel lines that meet the angle relationship with the reference positioning block, 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 not hinder the other structures and functional settings on the same side of the external pressure plate 1. Based on this, the angle between any two positioning blocks set on the external pressure plate 1 of the present invention is the same as the angle between the projections of the corresponding axially parallel built-in planes on the radial plane; the angle relationship of the positioning blocks set by the above method corresponds to the angle between the projections of the axially parallel built-in plane to be processed on the radial plane, and the angle relationship of the projections of the axially parallel built-in plane to be processed on the radial plane is consistent with the design expectations based on the above positioning block alignment and processing.

[0135] Specifically, Figure 1As 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.

[0136] 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.

[0137] 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.

[0138] At the same time, in order to further 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; 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.

[0139] 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 .

[0140] On the other hand, the present invention discloses a processing device for hollow parts with built-in axially parallel planes, which, in addition to the above-mentioned processing mold, also includes: a vertical rotary worktable 5, 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 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 on the side close to the external pressure plate 1 is connected to a processing tool 8.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] In order to illustrate the technical advancement of the present invention, the following embodiments are further disclosed:

[0145] Example 1

[0146] This embodiment discloses a method for positioning a built-in axial parallel plane of a hollow part, such as Figure 8 As shown, the following steps are included:

[0147] Step 1: Based on a polyhedron that rotates coaxially with the processing mold, 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;

[0148] Specifically, one end of the processing mold is fixedly connected to the vertical rotary table, and the other end is used as a 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 arranged according to the angle of the positioning block; a polyhedron rotating coaxially with the processing mold is arranged on one side of the feed end of the processing mold, and the polyhedron is provided with a continuous vertical and horizontal reflective side surface, and each time a reflective side surface is rotated, the polyhedron rotates 360 / N degrees; wherein N is the number of reflective surfaces of the polyhedron;

[0149] Step 2: 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;

[0150] Step 3: Processing the preformed hollow part blank after alignment to obtain the built-in plane.

[0151] Specifically, step 1, based on a polyhedron rotating coaxially with the processing mold, setting a positioning block parallel to the built-in plane of the target hollow part includes the following steps:

[0152] S101: 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 external pressing plate 1 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 coordinate axis z'-axis is set in the plane of the horizontal rotary table at the initial position in the direction perpendicular to the x'-axis, 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; the first positioning block 1011 is set in the solid area outside the external pressing plate 1 in the direction perpendicular to the z'-axis;

[0153] S102: The included angle between the first positioning block 1011 and the second positioning block 1012 is 60°; a polyhedron is fixedly provided in the central area of ​​the horizontal rotary worktable; the polyhedron is rotated 60°, and a second positioning block 1012 is provided in the solid area outside the external pressing plate 1 perpendicular to the z' axis direction;

[0154] S103: Based on the angle (90°) between the first positioning block and the third positioning block and the angle (120°) between the first positioning block and the fourth positioning block, the third positioning block and the fourth positioning block are sequentially set according to the method of S102.

[0155] Furthermore, in order to improve the positioning accuracy of the positioning block on the external pressure plate 1, it is necessary to calibrate the positional relationship of the first positioning block 1011, the second positioning block 1012, the third positioning block 1013 and the fourth positioning block 1014 relative to the z' axis, which includes the following steps:

[0156] S1011: Setting the positioning block perpendicular to the z' axis direction by visual judgment;

[0157] S1012: By setting up a dial indicator on the machine tool spindle, parallel movement along the dial indicator coordinate axis x' axis can be achieved, and the dial indicator displacement probe contacts a side of the positioning block to be measured; the change in the dial indicator pointer reading is calculated, and the angle of the positioning block is adjusted until η is less than 1%, then it is determined that the alignment is completed.

[0158] 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 S102, which includes the following steps:

[0159] S1021: Setting the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; selecting the first positioning block 1011 in S101 set perpendicular to the z' axis as the initial position, 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 polyhedral prism is 0, and fixing the photoelectric autocollimator;

[0160] S1022: For the second positioning block 1012, the number of reflecting surfaces N of the polyhedron satisfies N=k×360 / α=6k, where k is a positive integer. Therefore, considering the difficulty and cost of processing the polyhedron, a hexahedron, a dodecahedron and an octahedron can be selected; the polyhedron is rotated through k reflecting surfaces (the corresponding k values ​​of the hexahedron, the dodecahedron and the octahedron are 1, 2, and 3), 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.

[0161] Furthermore, in order to improve the accuracy of the positioning block timing, step 2 includes using a dial indicator to calibrate the positioning block position, which specifically includes the following steps:

[0162] S201: adjusting the rotation angle of the horizontal rotary table, and setting the positioning block approximately horizontally by visual judgment;

[0163] S202: 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 indicates a change of less than 1% when the dial indicator needle slides from one end to the other end on the positioning block, thereby determining that the positioning block is strictly horizontal.

[0164] 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.

[0165] The process between step 1 and step 2 also includes pre-processing the preformed hollow part blank;

[0166] Specifically, the pre-processing process of the preformed hollow part blank includes the following steps:

[0167] S104: Select a group of centrosymmetric first positioning through holes 105, take the center line of the two as the reference line of the first positioning block, and obtain the angle α0 between the reference line and the first positioning block;

[0168] S105: 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 α0 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°-α0;

[0169] S106: processing the mold to be processed after the preliminary alignment of the first built-in plane is completed with a 0.2 mm margin;

[0170] S107: Based on alpha t1 The angle α1 between the first built-in plane and the second built-in plane is used to obtain the rotary table rotation angle α required for the second positioning block to align t2 , based on α t1 The angle α2 between the first built-in plane and the third built-in plane is used to obtain the rotation angle α of the rotary table 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.

[0171] Preferably, in order to ensure positioning accuracy, the angle α0 between the reference line and the first positioning block is obtained by a photoelectric autocollimator.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] Specifically, the tool used for processing in S106 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.

[0176] Specifically, the hollow part is made of titanium alloy.

[0177] 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:

[0178] S108: heat treatment at 120°C for 6 hours, followed by air cooling to room temperature;

[0179] S109: Treat at -50°C for 2 h, then allow to warm up at room temperature;

[0180] S110: Heat treatment at 120℃ for 6h, then air cooling or furnace cooling to room temperature.

[0181] This embodiment realizes the relative position relationship positioning between the built-in planes of the target hollow part by setting a positioning block parallel to the built-in plane of the target hollow part, and converts the angular relationship of the projection of the built-in plane of the target hollow part on the radial plane into the angular relationship between the positioning blocks; 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 realizing the absolute position relationship positioning of the built-in plane of the target hollow part relative to the horizontal plane.

[0182] Example 2

[0183] This embodiment discloses a method for processing a hollow part. Figure 7 As shown, in addition to all the steps of Example 1, the steps of processing the preformed hollow part blank after alignment are also included:

[0184] S301: Using the x, y, and 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;

[0185] S302: 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;

[0186] S303: Processing the aligned part from inside to outside based on the processing program to obtain a finished part with a corresponding built-in plane.

[0187] Example 3

[0188] This embodiment discloses a processing mold for a hollow part with an axially parallel plane built in, 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.

[0189] 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.

[0190] like Figure 5 As 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.

[0191] like Figure 5As shown: there are four positioning blocks 101 with the same size, the ratio of the length to the width or the height of the positioning block is 5, and the height and the width are equal; a larger ratio of the length to the width or the 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.

[0192] 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.

[0193] 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.

[0194] 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 of the hollow part 4 connected to the external pressure plate 1; the positioning pin 106 is matched with the first positioning through hole 105 and the second positioning hole 401 to prevent radial relative sliding and ensure stability and accuracy during processing.

[0195] 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 .

[0196] Example 4

[0197] This embodiment discloses a processing device for a hollow part with a built-in axially parallel plane, comprising the processing mold described in Example 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.

[0198] 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.

[0199] 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.

[0200] 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 plane 4021' to be processed, and at the same time, the first plane 4021' to be processed is placed within the processing range 405 of the processing tool 8.

[0201] 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. A method for positioning a built-in axial parallel plane of a hollow part, characterized in that: The following steps are involved: Based on a polyhedral prism that rotates coaxially with the processing mold, 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; Setting a positioning block parallel to the built-in plane of the target hollow part includes: determining the angle of the positioning block corresponding to the parallel built-in plane of the two target hollow parts according to the angle of the radial projection of the built-in plane of the two target hollow parts, and sequentially setting each positioning block according to the angle of the positioning block; Setting the positioning block parallel to the built-in plane of the target hollow part includes the following steps: Taking the geometric center of the outer side surface of the feed end of the processing mold as the origin and the radial plane of the processing mold as the x'z' plane, construct an x'y'z' three-axis coordinate system, and set a first positioning block as a reference positioning block in the x'z' plane; Obtain an included angle α between the first positioning block and the second positioning block, and fix a polyhedron in the central area of ​​the horizontal rotary table; rotate the polyhedron by α degrees, and set a second positioning block in an area in the x'z' plane, wherein the included angles of the second positioning block with the x' axis and the z' axis are the same as those of the first positioning block; The Mth positioning block is set based on the angle between the first positioning block and the Mth positioning block; wherein M is a positive integer greater than or equal to 3.

2. The positioning method according to claim 1, characterized in that: Setting the Mth positioning block includes correcting the positioning accuracy of the positioning block using a dial indicator.

3. The positioning method according to claim 2, characterized in that: Use the dial indicator to calibrate the positioning accuracy of the positioning block. The following steps are involved: Set the positioning block vertically in the z' axis direction; A dial indicator is set up on the machine tool spindle and the spindle is moved along the x' axis. The angle between the positioning block and the z' axis is fine-tuned according to the indication. When the dial indicator needle slides from one end to the other on the positioning block, the indication of the dial indicator pointer changes below the threshold value, and it is determined that the positioning block is strictly perpendicular to the z' axis direction.

4. The positioning method according to claim 1, characterized in that: The polyhedron is rotated by α degrees, including approximately rotating the polyhedron by α degrees based on the central angle of a circle corresponding to the reflection surface of the polyhedron, and correcting the rotation angle of the polyhedron by a photoelectric autocollimator.

5. The positioning method according to claim 4, characterized in that: The method of correcting the rotation angle of the polyhedron by using a photoelectric autocollimator includes the following steps: Set the plane where the photoelectric autocollimator is parallel to the coordinate axes x' and z', select the position of the polyhedron before the polyhedron is rotated α degrees as the initial position, adjust the angle of the photoelectric autocollimator relative to the x' axis, so that the reading of the photoelectric autocollimator on any optional reflective surface of the polyhedron is 0, and fix the photoelectric autocollimator; 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; wherein k satisfies: k=α×N / 360, k is a positive integer, and N is the number of reflecting surfaces of the polyhedron.

6. The positioning method according to claim 1, characterized in that: Alignment of the built-in plane of the target hollow part includes correction of the positioning accuracy of the positioning block using a dial indicator.

7. The positioning method according to claim 6, characterized in that: The positioning accuracy of the positioning block is corrected using a dial indicator, including the following steps: Adjust the rotation angle of the horizontal rotary table to which the positioning block is fixedly connected, and set the positioning block approximately horizontally; A dial indicator is mounted on the machine tool spindle, and the machine tool spindle is moved along the radial plane parallel to the projection line of the preformed hollow part blank on the horizontal plane, and the angle of the positioning block is fine-tuned according to the indication of the dial indicator pointer until the dial indicator pointer indication changes below the threshold when the dial indicator needle slides from one end to the other on the positioning block, and the positioning block is determined to be strictly horizontal.

8. The positioning method according to claim 7, characterized in that: The change in the indication of the dial indicator pointer η satisfies: η=S max -S min , the threshold is 1%.

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