Processing device and processing method for a hollow part

Abstract

The present invention relates to the technical field of mechanical manufacturing, and particularly to a processing device and a processing method for a hollow part. The processing device includes: an external pressing plate, a pull rod, a bottom fixing member, a vertical rotary table, a machine tool platform, a machine tool spindle, and a processing tool; the external pressing plate and the bottom fixing member are fixedly connected through the pull rod to form a fixing area in the middle for clamping and fixing the target hollow part; a positioning block parallel to the built-in axial parallel plane is provided at one end of the external pressing plate away from the bottom fixing member; one side of the vertical rotary table is fixedly connected to the bottom fixing member, and the other side is movably connected to the machine tool platform; the other side of the machine tool platform is movably connected to the machine tool spindle; the processing tool is arranged at the end of the machine tool spindle on the side close to the external pressing plate. By setting the positioning block, the present invention realizes the visual positioning and calibration of the target plane; at the same time, with the help of an optoelectronic autocollimator to optimize the positioning accuracy of the positioning block, the positioning accuracy is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material manufacturing, and particularly relates to a processing device and a processing method for a hollow part. Background Art

[0002] There is a wide demand for high-precision internally shaped hollow parts in the aviation field. Especially for a new generation of aviation materials represented by light alloys (such as magnesium-aluminum alloy), materials such as light alloys cannot be welded or the welding precision is difficult to control, and the casting process is difficult to meet the precision requirements for internal shaped structures; currently, the production of light alloy hollow parts mainly relies 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: fixing the preformed hollow part blank and adjusting the coordinate position of the tool for processing; this method has defects such as poor precision and difficult calibration due to the large tool travel, complex calibration, and program control; another common processing method: fixing the preformed hollow part blank on a rotary table, restricting the tool to a limited area, and sequentially placing different areas of the preformed hollow part blank in the limited processing area of the tool by rotating the rotary table; this method generally needs to determine the rotation angle of the rotary table with the help of the angle scale of the rotary table to complete the alignment of the target plane. At present, the indexing precision of the vertical rotary table in the prior art is 0.01°, but due to factors such as superposition of part deformation and cumulative errors in other directions during the processing, it is not easy to ensure the angular tolerance between the combined planes, the risk of out-of-tolerance is relatively large, the yield rate is relatively low, and it still cannot meet the requirements of high-precision processing. Currently, there is an urgent need in the market for a processing device and a processing 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 processing device and a processing method for a hollow part to solve at least one of the problems such as low yield rate, low processing precision, and great influence by the precision of the machine tool itself in the prior art problems.

[0005] The object of the present invention is mainly achieved by the following technical solutions:

[0006] Processing device for a hollow part, comprising: an external pressing plate, a pull rod, a bottom fixing member, a vertical rotary table, a machine tool platform, a machine tool spindle and a processing tool; the external pressing plate is located at one end of the pull rod, the bottom fixing member is located at the other end of the pull rod, the external pressing plate and the bottom fixing member are fixedly connected through the pull rod, and a fixing area for clamping and fixing a preformed hollow part blank is provided between the external pressing plate and the bottom fixing member; an axially parallel plane is arranged inside the hollow part, a positioning block parallel to the axially parallel plane is arranged at one end of the external pressing plate away from the bottom fixing member, a central hole for the processing tool to enter and exit is arranged at the center of the external pressing plate, and a solid area is arranged at the outer peripheral edge of the central hole of the positioning block; the vertical rotary table is fixedly connected to the end of the bottom fixing member facing away from the external pressing plate; one side of the machine tool platform is movably connected to the vertical rotary table, and the other side of the machine tool platform is movably connected to the machine tool spindle; the processing tool is arranged at the end of the machine tool spindle on the side close to the external pressing plate.

[0007] Preferably, the control program of the processing device includes: restricting the processing range of the processing tool to a fixed area on one side of the center relative to the preformed hollow part blank.

[0008] Preferably, one or more positioning blocks are provided, corresponding one by one to the planes parallel to the built-in axis.

[0009] Preferably, a multi-faceted prism that rotates coaxially is established at the tool feed end of the processing die, and the angular relationship between the radial projections of the positioning blocks is determined through the multi-faceted prism.

[0010] Preferably, the side surface of the multi-faceted prism is a rectangular reflecting surface perpendicular to the horizontal plane and having the same size.

[0011] Preferably, a first positioning block is established as a reference positioning block, and based on the angle of the Mth positioning block relative to the reference positioning block, the multi-faceted prism is rotated by k side surfaces to determine the position of the Mth positioning block relative to the reference positioning block, where k is a positive integer and k = α m / (360 / N), α m The angle of the Mth positioning block relative to the reference positioning block, 360 / N is the central angle corresponding to a single reflecting surface of the multi-faceted prism; M is an integer greater than or equal to 3, 360 / N is the center of the circle corresponding to a single reflecting surface of the multi-faceted prism, and N is the number of reflecting surfaces of the multi-faceted prism.

[0012] Preferably, the processing device is provided with a movable connection structure for adjusting the pressing degree of the external pressing plate and the bottom fixing member on the preformed hollow part blank.

[0013] Preferably, the movable connection structure includes: a pull rod mounting hole provided at the edge of the body of the external pressing plate; a pull rod having a thread at one end and fixedly connected to the bottom fixing member at the other end, and a nut matching the thread.

[0014] Preferably, the machining tool is a carbide tool that meets the following requirements: diameter 12 mm to 20 mm, chamfer radius 1 mm to 3 mm.

[0015] A method for processing a hollow part uses the above processing device.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0017] (1) 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: aligning and positioning the axially parallel built-in plane and cutting the axially parallel built-in plane. 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.

[0018] (2) 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.

[0019] (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, 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.

[0020] (4) The present invention sets a positioning block parallel to the radial projection of the built-in axially parallel plane, 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.

[0021] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combined solutions. Other features and advantages of the present invention will be described in the following specification, and some advantages can be made obvious from the specification or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained from the content specifically pointed out in the embodiments of the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings are only for the purpose of illustrating specific embodiments and are not considered as a limitation of the present invention. Throughout the drawings, the same reference signs denote the same components.

[0023] Figure 1 It is a schematic assembly view of a hollow part with axially parallel internal planes and a processing die from a 45° top view perspective in an embodiment of the present invention;

[0024] Figure 2 It is a schematic view of a hollow part with axially parallel internal planes from a 45° top view perspective in an embodiment of the present invention;

[0025] Figure 3 It is a sectional view of plane A-A of a hollow part with axially parallel internal planes in an embodiment of the present invention;

[0026] Figure 4 It is a sectional view of plane A-A of a blank of a hollow part with axially parallel internal planes in an embodiment of the present invention;

[0027] Figure 5 It is a schematic assembly view of an unformed hollow part with axially parallel internal planes, an external pressure plate and a positioning block from a 45° top view perspective in an embodiment of the present invention;

[0028] Figure 6 It is a schematic view of a processing device and an installation method of a hollow part with axially parallel internal planes in an embodiment of the present invention;

[0029] Figure 7 It is a flowchart of a processing method of a hollow part with axially parallel internal planes in an embodiment of the present invention;

[0030] Figure 8 It is a flowchart of a positioning method for axially parallel internal planes of a hollow part in an embodiment of the present invention.

[0031] Reference Signs:

[0032] External pressure plate 1; pull rod 2; bottom fixing part 3; hollow part 4; rotary table 5; machine tool platform 6; machine tool spindle 7, machining tool 8; positioning block 101; first positioning block 1011; second positioning block 1012; central hole 102; edge solid area 103; pull 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 the target hollow part; first built-in plane 4021; second built-in plane 4022; first target plane 4021'; second target plane 4022'; part body 403; machining range 405 of the machining tool. Detailed implementation mode

[0033] The following will specifically describe the preferred embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings form a part of the present invention and are used together with the embodiments of the present invention to explain the principles of the present invention, and are not used to limit the scope of the present invention.

[0034] In order to clearly elaborate the technical solution of the present invention, the following technical terms are further defined:

[0035] Alignment:

[0036] The present invention defines alignment as the state where the plane to be machined is parallel to the horizontal plane.

[0037] The included angle between two straight lines l1 and l2:

[0038] The angle formed when the straight line l1 is rotated counterclockwise until it is parallel to l2.

[0039] Currently, in the prior art, the indexing accuracy of the vertical rotary table is higher than 0.01°. Limited by the accuracy of the vertical rotary table, it is difficult to further improve the horizontal alignment accuracy of the plane to be machined. To solve the above problems, the present invention provides a machining device and a machining method for the axially parallel built-in plane in a high-precision hollow part that do not rely on the indexing accuracy of the rotary table.

[0040] On the one hand, the present invention discloses a machining device for a hollow part, including: an external pressure plate 1, a pull rod 2 with one end connected to the external pressure plate 1, a bottom fixing part 3 connected to the other end of the pull rod 2, a vertical rotary table 5 fixedly connected to the end of the bottom fixing part 3 facing away from the external pressure plate 1, a machine tool platform 6 movably connected to one side of the vertical rotary table 5, and a machine tool spindle 7 movably connected to the other side of the machine tool platform 6. A machining tool 8 is connected to the end of the machine tool spindle 7 close to the external pressure plate 1.

[0041] There is a fixing area for clamping and fixing the preformed hollow part blank between the outer pressing plate 1 and the bottom fixing part 3; at one end of the outer pressing plate 1 away from the bottom fixing part 3 (i.e., the outer end face), there is a positioning block 101 parallel to the built-in axial parallel plane of the preformed hollow part blank. A central hole 102 for the machining tool 8 to enter and exit is provided at the center of the outer pressing plate 1, and the positioning block 101 is arranged in the solid area 103 on the outer peripheral edge of the central hole 102.

[0042] During implementation, the machining range of the machining tool 8 is restricted to the fixing area on one side of the center relative to 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 fixing area where the machining tool 8 is located during machining, realizing the machining of different areas of the preformed hollow part blank.

[0043] 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 machining the built-in plane of the preformed hollow part blank to obtain the corresponding target hollow part, it is necessary to align the built-in plane to be machined of the preformed hollow part blank.

[0044] Specifically, as Figure 2 shown, the formed hollow part 4 is a hollow part with an inner side wall provided with an inner plane 402 parallel to the axis; Figure 3 is a cross-sectional view of the formed hollow part 4 in the radial section (A - A plane) where the center of the inner plane 402 parallel to the axis is located: multiple inner planes 402 parallel to the axis are not parallel to each other and form a certain angle. Figure 4 is a cross-sectional view of the raw material blank of the hollow part 4 in the radial section (A - A plane): the raw material blank of the hollow part 4 is a cylindrically symmetric part centered on the axis.

[0045] As Figure 1 shown: the inner side wall of the hollow part 4 is provided with a first inner plane 4021 and a second inner plane 4022; the first inner plane 4021 and the second inner plane 4022 are not parallel to each other and form a certain angle.

[0046] On the outer end face of the outer pressing plate 1 of the processing die of the above-mentioned hollow part, there are a first positioning block 1011 and a second positioning block 1012; the first positioning block 1011 is parallel to the first inner plane 4021, and the second positioning block 1012 is parallel to the second inner plane 4022.

[0047] The positioning block 101 has one or more, and corresponds one-to-one with the inner plane 402' of the target hollow part.

[0048] Figure 5The state where the first built-in plane 4021 and the second built-in plane 4022 are not yet machined is shown: on the side wall of the preformed hollow part blank, there are a first target plane 4021' and a second target plane 4022'; the first target plane 4021' at the dotted line is obtained through machining. Figure 1 the first built-in plane 4021 in Figure 1 , and the second target plane 4022' at the dotted line is obtained through machining. 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'; through parallel transfer, the included angle between the first built-in plane 4021 and the second built-in plane 4022 is the same as the included angle between the first target plane 4021' and the second target plane 4022'.

[0049] Specifically, as Figure 5 shown, since the built-in planes 402' of the target hollow part are axially parallel, their projections onto the end face along the axis are straight line segments; the positioning block 101 is set to be parallel to the projection of the built-in plane 402' of the target hollow part onto the end face along the axis.

[0050] During implementation, the positioning block 101 is set to be strip-shaped and fixed to the outer end face of the external pressing 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, it is more convenient and accurate to judge the horizontal state of the built-in plane of the target hollow part corresponding to the positioning block 101; and, since the tool is perpendicular to the horizontal plane, by adjusting the positioning block 101 to be horizontal, the alignment of the corresponding built-in plane of the target hollow part can be achieved.

[0051] Compared with the prior art, in the present invention, by setting a positioning block parallel to the radial projection of the built-in plane of the target hollow part, the inclination angle of the built-in plane of the target hollow part relative to the horizontal plane is converted into the included angle between the positioning block and the horizontal plane. Among them, the built-in plane of the target hollow part is abstract and invisible before machining is completed, while the positioning block is specifically visible. The advantage of doing this is that: the positioning block can be measured and corrected before machining the built-in plane, so as to achieve the correction of the built-in plane of the target hollow part and improve the machining accuracy.

[0052] Furthermore, the positioning block 101 is fixed to the body of the external pressing plate 1; the ratio of the length of the positioning block to its width or height is greater than 2; when detecting the horizontal state of the positioning block 101, by using the relatively large ratio of the length of the positioning block to its width or height, it is beneficial to obtain more sensitive signals at both ends of the top of the positioning block, which is beneficial to further improving the alignment accuracy of the built-in plane corresponding to the positioning block 101.

[0053] Specifically, the angular relationship between the radial projections of multiple positioning blocks is calibrated by an optoelectronic autocollimator, and the rotary table calibrates and positions the multiple positioning blocks 101. Specifically, the external pressing plate 1 is fixed to the rotary table, and based on the included angle of the radial projections of the built-in planes of the target hollow part, the rotary table is rotated to determine the installation positions of the positioning blocks.

[0054] For the case of machining multiple axially parallel built-in planes, multiple positioning blocks 101 that are parallel to the projections of the built-in planes in the radial plane need to be arranged on the external pressing plate 1. According to the principle of parallel transmission, the included angle between the projections of any two axially parallel built-in planes in the radial plane is the same as the included angle between the corresponding positioning blocks 101 in the radial plane.

[0055] During implementation, the first positioning block 101 is set as the reference positioning block, and the remaining positioning blocks are set according to the included angle with the reference positioning block. It should be noted that the positioning blocks can be arranged on multiple parallel lines that satisfy the angular relationship with the reference positioning block. At the same time, there are multiple feasible installation positions for the positioning blocks to translate on the same parallel line. Therefore, an installation position where the positioning blocks can be set without obstruction needs to be selected on the outer side of the external pressing plate 1. The positioning blocks set at this installation position should not obstruct the other structures and functions on the same side of the external pressing plate 1. Based on this, the included angle between any two positioning blocks set on the external pressing plate 1 is the same as the included angle between the projections of the corresponding axially parallel built-in planes in the radial plane. The angular relationship of the positioning blocks set by the above method corresponds to the included angle of the projections of the axially parallel built-in planes of the target hollow part in the radial plane. The angular relationship of the projections of the axially parallel built-in planes obtained by machining based on the alignment of the above positioning blocks is consistent with the design expectation.

[0056] More specifically, multiple positioning blocks 101 determine the angular relationship between the radial projections by establishing a multi-faceted prism at the center of the external pressing plate 1.

[0057] The side surfaces of the multi-faceted prism are rectangular reflecting surfaces that are perpendicular to the horizontal plane and have the same size.

[0058] The first positioning block is established as the reference positioning block. By rotating the multi-faceted prism by k side surfaces, based on the second positioning block,..., the positions of the second positioning block,..., the Mth positioning block relative to the reference positioning block are determined according to the included angles of the second positioning block,..., the Mth positioning block relative to the reference positioning block, where k is a positive integer and k = α m / (360 / N), α mis the second positioning block,..., the included angle of the Mth positioning block relative to the reference positioning block, where M is the positioning block number, and 360 / N is the central angle corresponding to a single reflecting surface of the multi-faceted prism. To match the correction of the reflecting surface of the multi-faceted prism by the optoelectronic autocollimator, the rotation of the multi-faceted prism rotates in basic units corresponding to the central angle of a single reflecting surface; in the case where it is less than one basic unit (k is not an integer), the value of N should be adjusted to satisfy k being a positive integer, determine the number of reflecting surfaces of the multi-faceted prism, and obtain a suitable multi-faceted prism.

[0059] Compared with the prior art, the present invention completes the transfer 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. Therefore, the machining of the built-in plane of the target hollow part can be decomposed into two parts: aligning and positioning the built-in plane of the target hollow part and machining the built-in plane of the target hollow part; thus, when designing the machining program, the present invention does not need to add a positioning function module. Compared with the prior art of fixed cutting machining of the workpiece to be machined, it reduces the complexity of the program design and the travel of the machining tool, and improves the machining accuracy and reliability.

[0060] Specifically, as Figure 1 shown: The machining tool can freely enter and exit the central hole 102, so it can meet the machining of the inside of the preformed hollow part blank; the outside of the edge solid region 103 is used to fix the positioning block 1, and the inside is press-fitted and connected to the hollow part 4.

[0061] Furthermore, in order to realize the fastening connection between the bottom fixing part 3 and the external pressing plate 1, a pull rod mounting hole 104 is provided at the edge of the body of the external pressing plate 1; one end of the pull rod 2 is provided with a thread, and the other end is fixedly connected to the bottom fixing part 3, and the thread matches the nut. The pull rod mounting hole 104, the pull rod 2 and the nut form a movable connection structure for adjusting the pressing degree of the external pressing plate 1 and the bottom fixing part 3 on the hollow part 4, as Figure 1 shown, the movable connection structure includes: a pull rod mounting hole 104 provided at the edge of the body of the external pressing plate 1; a pull rod 2 with a thread at one end and fixedly connected to the bottom fixing part 3 at the other end and a nut matching the thread; and it is press-fitted and connected to the edge solid region 103 through the nut. The thread setting enables the pull rod 2 to adjust the tightening degree of the bottom fixing part 3 and the external pressing plate 1, and adjust the end surface pressing strength of the preformed hollow part blank.

[0062] Preferably, the pull rod mounting holes 104 are symmetrically arranged about the center of the external pressing plate 1, and the pull rods 2 corresponding to the number of pull rod mounting holes 104 pass through the pull rod mounting holes 104 and are fixedly connected to the edge solid region 103, applying force evenly in all directions relative to the centers of the edge solid region 103 and the bottom fixing part 3.

[0063] Meanwhile, in order to further improve the fastening degree between the preformed hollow part blank and the mold and prevent relative sliding, as Figure 3 shown, a plurality of first positioning through holes 105 are provided in the edge solid region 103; as Figure 4 shown, a second positioning hole 401 is provided on one side of the preformed hollow part blank connected to the external pressing plate 1; one end of the first positioning through hole 105 is axially movably connected to the preformed hollow part blank; the preformed hollow part blank can be radially rotationally locked by matching connection of the positioning pin 106 with the first positioning through hole 105 and the second positioning hole 401, preventing radial relative sliding and ensuring stability and accuracy during processing.

[0064] 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 in the second positioning hole 401.

[0065] Preferably, in order to take into account the use under different processing precisions and have wide applicability, the machining tool 8 is selected as a cemented carbide tool, satisfying: diameter 12 mm - 20 mm, chamfer radius 1 mm - 3 mm.

[0066] On the other hand, the present invention provides a processing method for a hollow part, using the above-mentioned processing device, as Figure 7 shown, including the following steps:

[0067] Step 1: Set positioning blocks parallel to the built-in plane of the target hollow part outside the feed end of the processing mold;

[0068] 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 included angle of the positioning blocks corresponding to the built-in planes of the two target hollow parts in parallel is confirmed according to the included angle of the radial projections of the built-in planes of the two target hollow parts, and each positioning block is sequentially set according to the included angle of the positioning blocks.

[0069] During implementation, the first positioning block 1011 is set as the reference positioning block, and the positioning blocks are set according to the included angles of the remaining positioning blocks relative to the reference positioning block.

[0070] It should be noted that there are multiple installation positions for the positioning blocks that satisfy the angular relationship with the reference positioning block. The straight lines where all the installation positions are located are parallel to each other and have the same included angle with the reference positioning block. Select an installation position on the outer side of the outer pressing plate 1 to set the positioning block without obstruction. The positioning block set at this installation position should not obstruct the other structures and functions on the same side of the outer pressing plate 1. Based on this, the included angle between any two positioning blocks set on the outer pressing plate 1 is the same as the included angle between the projections of the corresponding built-in planes of the two positioning blocks in the radial plane; the angular relationship of the positioning blocks set by the above method corresponds to the included angle between the projections of the axially parallel built-in planes of the target hollow part in 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 included angle between the positioning block and the horizontal plane.

[0071] Step 2: Based on the positioning block, complete the alignment of the preformed hollow part blank with the built-in plane of the target hollow part corresponding to the positioning block;

[0072] Specifically, adjust the rotation angle of the vertical rotary table until the positioning block is horizontal. Based on the principle of parallel transfer, it can be realized that the built-in plane of the target hollow part corresponding to the positioning block is placed horizontally and within the machining range of the machining tool, and the alignment of the built-in plane of the target hollow part is completed; the machining range of the machining tool is restricted to a fixed area on one side of the center of the relative hollow part through program control.

[0073] Step 3: Machine the aligned preformed hollow part blank to obtain the built-in plane; specifically, based on the machining program, the machining tool removes the surplus material from the inner wall to the outer wall of the preformed hollow part blank to obtain the built-in plane of the target hollow part.

[0074] On the one hand, the axially parallel built-in plane to be machined is abstract and invisible before the machining is completed, while the positioning block is concrete and visible. The advantage of using the positioning block for zero adjustment in the present invention is that, compared with the prior art, the present invention converts the zero adjustment of the axially parallel built-in plane to be machined into the horizontal adjustment of the corresponding positioning block, and the positioning block can be measured and corrected before machining the built-in plane, realizing the correction of the axially parallel built-in plane to be machined and improving the machining accuracy;

[0075] On the other hand, the machining error of the tool is proportional to its travel. Compared with the prior art, the present invention adopts the rotation mode of the preformed hollow part blank to realize the machining of different regions of the preformed hollow part blank. The tool only needs to move within a local range on one side of the area to be machined, reducing the machining travel of the tool. Compared with the way that the tool accumulatively moves between each machining area in the prior art, the cumulative error caused by the increase in the tool travel is reduced, and the accuracy is improved.

[0076] Specifically, the step of setting the positioning block parallel to the built-in plane of the target hollow part outside the feed end of the processing die in Step 1 includes the following steps:

[0077] S101: Fix the external pressing plate 1 coaxially on the horizontal rotary table with a set of first positioning through holes 105 that are centrosymmetric with respect to the geometric center of the feed end of the processing die; taking the geometric center of the feed end of the processing die as the origin, using the center connection line of the first positioning through holes 105 in the initial position as the coordinate axis x'-axis, establish the coordinate axis z'-axis in the plane of the horizontal rotary table in the initial position perpendicular to the x'-axis direction, and use the perpendicular line passing through the origin and perpendicular to the coordinate axes x'-axis and z'-axis as the y'-axis; a first positioning block 1011 is arranged in the solid area outside the external pressing plate 1 in the direction perpendicular to the z'-axis; it should be noted that the initial position is an arbitrarily selected position after fixing the horizontal rotary table at the position of the external pressing plate 1 as the initial position. After constructing the coordinate system, when the horizontal rotary table rotates, it has no influence on the coordinate system.

[0078] S102: Obtain the included angle α between the first positioning block 1011 and the second positioning block 1012. A multi-sided prism is fixedly arranged in the central area of the horizontal rotary table; rotate the multi-sided prism by α degrees, and set a second positioning block 1012 in the solid area outside the external pressing plate 1 in the direction perpendicular to the z'-axis;

[0079] S103: Based on the included angle between the first positioning block and the Mth positioning block, set the Mth positioning block according to S102, where M is a positive integer greater than or equal to 3.

[0080] It should be noted that S101 - S103 are implemented on the horizontal rotary table, which is different from the vertical rotary table described in steps 1 - step 3: the rotation plane of the horizontal rotary table is horizontally arranged and is the worktable of a horizontal machining center; the rotation plane of the vertical rotary table is vertically arranged with respect to the horizontal plane.

[0081] It should be noted that in order to ensure the consistency of the angular relationship relative to the first positioning block, in S102 and S103, when setting the second positioning block, the third positioning block,..., the Mth positioning block, the rotation direction of the multi-sided prism is the same.

[0082] Specifically, in order to calibrate the positioning accuracy of the positioning block in the direction perpendicular to the z-axis, the steps for setting the first positioning block 1011 in the direction perpendicular to the z'-axis in S101, the second positioning block 1012 in the direction perpendicular to the z'-axis in S102, and the third positioning block,..., the Mth positioning block in S103 include:

[0083] S1011: Arrange the positioning block in the direction perpendicular to the z'-axis;

[0084] S1012: Mount a dial indicator on the machine tool spindle and let the spindle translate along the x-axis, and gently tap the positioning block to fine-tune its angle according to the reading until the change in the reading of the dial indicator pointer is lower than the threshold value when the dial indicator needle slides from one end to the other end on the positioning block, and it is determined that the positioning block is strictly perpendicular to the z'-axis direction.

[0085] It should be noted that in S1011, the positioning block can be set perpendicular to the z'-axis by visual judgment or measuring the angle with an angle gauge. 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 perpendicular relationship between the positioning block and the z'-axis.

[0086] 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 displacement probe of the dial indicator contacts a side to be measured of the positioning block. If the side to be measured is not parallel to the x'-axis of the coordinate axis, there will be a displacement change of the displacement probe of the dial indicator on the side to be measured, resulting in a change in the dial indicator reading. If the side to be measured is parallel to the x'-axis of the coordinate axis, the change in the dial indicator reading cannot be detected or is 0.

[0087] Specifically, the side to be measured is the side of the positioning block parallel to the y'-axis of the coordinate axis.

[0088] Specifically, the change in the dial indicator pointer reading is introduced to evaluate the parallelism between the side to be measured and the x'-axis of the coordinate axis: if η is less than 1%, it is determined that the alignment is completed; the change in the reading η satisfies: η = S max -S min , where S max is the maximum value of the dial indicator pointer reading, and S min is the minimum value of the dial indicator pointer reading.

[0089] Specifically, in S102, the included angle between the first positioning block 1011 and the second positioning block 1012 is the same as the included angle between the projections of the first target plane 4021' and the second target plane 4022' on the radial plane. Among them, the first target plane 4021' is parallel to the first positioning block 1011; the second target plane 4022' is parallel to the second positioning block 1012.

[0090] Specifically, in S102, when the multi-faceted prism rotates by α degrees, it includes precision calibration of the rotation angle of the multi-faceted prism by an optical autocollimator.

[0091] Specifically, the optical autocollimator can measure the deflection angle between its emitted light and the received reflected light signal, and the measurement accuracy is higher than 0.8″. By adjusting the included angle between the optical autocollimator and the reflecting surface of the multi-faceted prism, when the reading of the optical autocollimator is 0, the reflecting surface of the multi-faceted prism is perpendicular to the emitted light direction of the optical autocollimator.

[0092] Specifically, in S102, the side surfaces of the multi-faceted prism are rectangular reflecting surfaces with the same size perpendicular to the horizontal plane.

[0093] 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.

[0094] Specifically, the polyhedron is rotated by α degrees in S102, which includes the following steps:

[0095] 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;

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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 axial rotation of the preformed hollow part blank, adjusting the positioning block to horizontal, and realizing the built-in plane alignment of the target hollow part corresponding to the positioning block.

[0100] Further, in order to improve the accuracy of the alignment of the positioning block, step 2 includes using a dial indicator to correct the positional tolerance of the positioning block, which specifically includes the following steps:

[0101] S201: Adjust the rotation angle of the horizontal rotary table to approximately horizontally set the positioning block;

[0102] 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 in the horizontal plane, and fine-tune the angle of the positioning block according to the dial indicator reading until the change in the dial indicator reading is less than the threshold value when the dial indicator needle slides from one end to the other end on the positioning block, and it is determined that the positioning block is strictly horizontal.

[0103] It should be noted that in S201, the positioning block can be approximately horizontally set by visual judgment or measuring the angle with an angle gauge; 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.

[0104] During implementation, installing a dial indicator on the machine tool spindle in S202 can achieve parallel movement along the projection line of the radial plane in the horizontal plane, and the displacement probe of the dial indicator contacts a side to be measured (top or bottom side) of the positioning block; if the side to be measured is not parallel to the projection line, there is a displacement change of the displacement probe of the dial indicator on the side to be measured, resulting in a change in the dial indicator reading; if the side to be measured is parallel to the projection line, the change in the dial indicator reading cannot be detected or is 0.

[0105] Specifically, the change in the dial indicator reading is introduced to evaluate the horizontal degree of the positioning block: if η is less than 1%, it is determined that the alignment is completed; the change in the reading η satisfies: η = S max -S min , where S max is the maximum value of the dial indicator reading, and S min is the minimum value of the dial indicator reading.

[0106] Preferably, the ratio of the length of the positioning block to its width or height is greater than 2; increasing the ratio of the length of the positioning block to its width or height is beneficial to obtaining a larger height difference at both ends of the top of the positioning block, enabling the dial indicator to have a larger change in reading and obtaining a more sensitive signal.

[0107] Compared with the prior art, the present invention realizes the alignment of the internal plane of the target hollow part by setting a positioning block parallel to the internal plane of the target hollow part and based on the horizontal setting of the positioning block, avoiding the limitation of the angle scale accuracy of the vertical rotary table on the positioning accuracy of the internal plane of the target hollow part. Further, the present invention corrects the positional tolerance of the positioning block in the state to be aligned by a dial indicator, greatly improving the positioning accuracy compared with the prior art, from 0.01° to 0.08″.

[0108] Optionally, the machining program in step 3 can be generated by machining programming software based on the three-dimensional models of the preformed hollow part blank and the finished machined part.

[0109] Specifically, the machine tool machining is based on the x, y, and z three-axis spatial coordinate system set by itself, where the x-axis is set parallel to the horizontal plane, the z-axis is set parallel to the axis of the machined part, and the y-axis is set perpendicular to the horizontal plane; the machine tool machining performs cutting processing on each point in the F(x, y, z) machining area within the preformed hollow part blank that has completed the alignment operation of the built-in plane to be machined through program settings.

[0110] During implementation, the machining range of the machining tool 8 is restricted to a fixed area on one side of the center of the preformed hollow part blank through program control; correspondingly, the rotation angle of the vertical rotary table 5 is adjusted to achieve machining of different areas of the hollow part 4.

[0111] It should be noted that the control program of the machine tool does not include an identification module for the position of the preformed hollow part blank. Therefore, before machining the hollow part 4 to obtain the corresponding built-in plane to be machined, it is necessary to complete the alignment of the built-in plane to be machined for the preformed hollow part blank.

[0112] Specifically, step 3 of machining parts using a machine tool includes the following steps:

[0113] S301: Construct the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the finished machined part in the programming software;

[0114] S302: Generate a machining program by the programming software based on the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the finished machined part;

[0115] S303: The machine tool processes the aligned part based on the machining program to obtain a finished part with the corresponding built-in plane.

[0116] Specifically, in S301, the three-dimensional models of the preformed hollow part blank and the finished machined part are constructed using the x, y, and z three-axis spatial coordinate system set by the machine tool itself, where the x-axis is set parallel to the horizontal plane, the y-axis is set parallel to the axis of the machined part, and the z-axis is set perpendicular to the horizontal plane; in S302, the programming software compares the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the finished machined part to confirm the machining area F(x, y, z) and generates a machining program.

[0117] In this field, for part machining, it is often machined in two or more times: on the one hand, to prevent local overheating during long-term machining, tool and material expansion and deformation, and reference position drift, which affect machining accuracy; on the other hand, different machining accuracies have different requirements for tools. Rough machining causes greater tool wear and reduces the service life of the tool.

[0118] Preferably, a preprocessing process for the preformed hollow part blank is further included between step 1 and step 2 to further improve the above technical problems, including the following steps:

[0119] S104: Select a group of centrally symmetric first positioning through holes 105, take the center line connecting the two as the reference line of the first positioning block, and obtain the included angle α0 between the reference line and the first positioning block;

[0120] S105: Fix the preformed hollow part blank on the rotary table through the processing die, and obtain the inclination angle α of the reference line with respect to the horizontal plane - , based on the included angle α0 and the angle α - Obtain the rotation angle α of the rotary table required for aligning the first positioning block; t1 ; Based on α t1 Complete the preliminary alignment of the first built-in plane; specifically, α t1 Satisfies: α t1 =α - +90° - α0;

[0121] S106: Machine the processing die that has completed the preliminary alignment of the first built-in plane with a margin of 0.2 mm to 0.6 mm;

[0122] S107: Based on α t1 and the included angle α1 between the first built-in plane and the second built-in plane, obtain the rotation angle α of the rotary table required for aligning the second positioning block t2 , based on α t1 and the included angle α2 between the first built-in plane and the third built-in plane, obtain the rotation angle α of the rotary table required for aligning the third positioning block t3 , …, based on α t and the included angle α between the Nth built-in plane and the first built-in plane N Obtain the rotation angle α of the rotary table required for aligning the Nth positioning block tN ; Specifically, the rotation angle α of the rotary table required for aligning the Nth positioning block tN , satisfies: α tN =α t1 +α N ; Based on α t2 , …, α tN Complete the preliminary alignment of the second built-in plane, …, the Nth built-in plane; Machine the preformed hollow part blank that has completed the preliminary alignment of the second built-in plane, …, the Nth built-in plane with a margin of 0.2 mm to 0.6 mm.

[0123] Preferably, in order to ensure the positioning accuracy, the included angle α0 between the reference line and the first positioning block is obtained through an optoelectronic autocollimator.

[0124] 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.

[0125] 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.

[0126] Specifically, S106-S107 utilizes the above-mentioned machine tool to process parts, and the tool in S106, S107 and step 3 is a cemented carbide tool that meets the following requirements: diameter 12mm-20mm, chamfer radius 1mm-3mm, and tool speed 800r / min-1500r / min.

[0127] Specifically, the hollow parts can be made of one or more of carbon steel, stainless steel, titanium alloy, aluminum alloy, and aluminum-magnesium alloy.

[0128] 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:

[0129] S108: heat treatment at 120±10℃ for 2h~6h, then air cooling to room temperature;

[0130] S109: Treat at -50±5℃ for 1h~3h, then let it warm up at room temperature;

[0131] S110: Heat treatment at 120±10℃ for 2h~6h, then air cool or cool in the furnace to room temperature.

[0132] 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.

[0133] In order to illustrate the technical advancement of the present invention, the following embodiments are further disclosed:

[0134] Example 1

[0135] This embodiment discloses a processing mold for a hollow part, 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.

[0136] Figure 2 Shows a 45° top-down view of the formed hollow part; Figure 3 Shows a sectional view of the radial section (plane A-A) where the center of the axially parallel built-in plane 402 is located; As Figure 2 And Figure 3 Shown: Multiple axially parallel built-in planes 402 are not parallel and form a certain angle. Figure 4 Shows a sectional view of the raw blank of the hollow part 4 in the radial section (plane A-A), as Figure 3 And Figure 4 Shown: The hollow part 4 is obtained by machining from the inside to the outside by the part body 403.

[0137] As Figure 5 Shown: The positioning block 101 is a cuboid and is fixed to the external pressing plate 1 through the axial side surface; By measuring the horizontal state of the positioning block 101, it is more convenient and accurate to judge the horizontal state of the built-in plane of the target hollow part corresponding to the positioning block 101; By adjusting the positioning block 101 to be horizontal, the alignment of the built-in plane of the corresponding target hollow part is achieved; At the same time, the positioning block can be measured and corrected before machining the built-in plane, so as to correct the built-in plane of the target hollow part and improve the machining accuracy.

[0138] As Figure 5 Shown: There are four positioning blocks 101, with the same size. The ratio of the length to the width or height of the positioning block is taken as 5; A larger ratio of length to width or height is beneficial to obtaining more sensitive signals at both ends of the top of the positioning block, which is beneficial to further improving the alignment accuracy of the built-in plane corresponding to the positioning block.

[0139] At the same time, multiple positioning blocks calibrate the angular relationship between their radial projections through an optoelectronic autocollimator, and calibrate and position multiple positioning blocks 101 on the external pressing plate 1 through a rotary table; For multiple axially parallel built-in planes to be machined, positioning blocks 101 corresponding to the projections parallel to the built-in planes in the radial plane need to be set on the external pressing plate 1; According to the principle of transitivity of parallelism, the angle between the projections of any two built-in planes in the radial plane is the same as the angle between the corresponding positioning blocks 101.

[0140] As Figure 1 Shown, the external pressing plate 1 is provided with an edge solid area 103 on the outer periphery of the central hole 102, and the edge solid area 103 is provided with a pull rod mounting hole 104 that is centrosymmetric with respect to the center of the external pressing plate 1; At the same time, the pull rod 2 is provided with a thread and is press-fitted and connected to the edge solid area 103 through a nut to realize the firm connection of the bottom fixing part 3 and the external pressing plate 1. Multiple pull rods 2 are fixedly connected to the edge solid area 103 through the pull rod mounting holes 104, and apply force evenly in all directions relative to the centers of the edge solid area 103 and the bottom fixing part 3.

[0141] As Figure 3 shown, the edge solid area 103 is provided with a plurality of first positioning through holes 105; as Figure 4 shown, on one side of the hollow part 4 connected to the external pressing plate 1, a second positioning hole 401 is provided; by matching and connecting the positioning pin 106 with the first positioning through hole 105 and the second positioning hole 401, radial relative sliding can be prevented, ensuring stability and accuracy during processing.

[0142] 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 in the second positioning hole 401.

[0143] Embodiment 2

[0144] This embodiment discloses a processing device for a hollow part, including the processing die described in Embodiment 1. As Figure 6 shown, it further includes: a vertical rotary table 5, one end of the vertical rotary table 5 is fixedly connected to the other end of the bottom fixing member 3 facing away from the external pressing plate 1, and the other end of the vertical rotary table 5 is movably connected to one side of the 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 pressing plate 1 is connected to a processing tool 8.

[0145] During implementation, a central hole 102 for the processing tool 8 to enter and exit is provided at the center of the external pressing plate 1; through program control, the processing range of the processing tool 8 is limited to a fixed area on one side of the center relative to the preformed hollow part blank; 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, meeting the processing requirements of different areas of the hollow part 4.

[0146] It should be noted that the control program of the machine tool does not include an identification module for the position of the hollow part 4. Therefore, before processing the corresponding internal plane to be processed of the hollow part 4, the internal plane to be processed of the hollow part 4 needs to be aligned.

[0147] As an example, as Figure 6 shown, through program control, the processing range of the processing tool 8 is limited to the bottom area of the hollow part 4; the rotation angle of the rotary table 5 relative to the machine tool platform 6 is adjusted until the first positioning block 1011 is horizontal, realizing 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.

[0148] Embodiment 3

[0149] This embodiment discloses a positioning method for an axially parallel plane inside a hollow part. Using the processing die described in Embodiment 1, as Figure 8 shown, it includes the following steps:

[0150] Step 1: Set positioning blocks parallel to the built-in plane of the target hollow part on the outer side of the feed end of the processing die.

[0151] Specifically, one end of the processing die is fixedly connected to the vertical rotary worktable, and the other end is the feed end. Determine the angle between the positioning blocks corresponding to the built-in planes of the two target hollow parts in parallel according to the angle of the radial projection of the built-in planes of the two target hollow parts, and set each positioning block in sequence according to the angle of the positioning blocks.

[0152] Step 2: Based on the positioning blocks, complete the alignment of the preformed hollow part blank with the built-in plane of the target hollow part corresponding to the positioning blocks.

[0153] Specifically, setting the positioning blocks parallel to the built-in plane of the target hollow part in Step 1 includes the following steps:

[0154] S101: Fix the external pressing plate 1 coaxially on the horizontal rotary worktable through a set of first positioning through holes 105 that are centrosymmetric with respect to the geometric center of the external pressing plate 1; taking the geometric center of the external pressing plate 1 as the origin, taking the center connection line of the first positioning through holes 105 in the initial position as the x'-axis, establish the coordinate axis z'-axis in the plane of the horizontal rotary worktable in the initial position perpendicular to the x'-axis direction, and take the perpendicular line passing through the origin and perpendicular to the coordinate axes x'-axis and z'-axis as the y'-axis; set the first positioning block 1011 in the vertical z'-axis direction in the solid area outside the external pressing plate 1.

[0155] S102: Obtain that the included angle between the first positioning block 1011 and the second positioning block 1012 is 60°; a multi-faceted prism is fixedly arranged in the central area of the horizontal rotary worktable surface; rotate the multi-faceted prism by 60°, and set the second positioning block 1012 in the vertical z'-axis direction in the solid area outside the external pressing plate 1.

[0156] S103: Based on the included angle between the first positioning block and the Mth positioning block, the steps are the same as S102, where M is an integer greater than or equal to 3

[0157] Furthermore, to improve the positioning accuracy of the positioning blocks on the external pressing plate 1, it is necessary to correct 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, including the following steps:

[0158] S1011: Set the positioning blocks perpendicular to the z'-axis direction by visual judgment.

[0159] S1012: By installing a dial indicator on the machine tool spindle, it can be realized to move parallel to the x'-axis of the dial indicator coordinate axis, and the displacement probe of the dial indicator contacts a side to be measured of the positioning block; calculate the change in the indication of the dial indicator pointer, and adjust the angle of the positioning block until η is less than 1%, then it is judged that the alignment is completed.

[0160] Furthermore, to improve the positioning accuracy of the positioning block on the external pressing plate 1, it is necessary to correct the rotation accuracy when the multi-sided prism rotates by α degrees in S102, including the following steps:

[0161] S1021: Set the photoelectric autocollimator parallel to the plane where the coordinate axes x' and z' are located; select the initial position when the first positioning block 1011 in S101 is set perpendicular to the z' axis direction, and adjust the angle between the photoelectric autocollimator and the x' axis so that the reading of the photoelectric autocollimator on any reflection surface of the multi-sided prism is 0, and then fix the photoelectric autocollimator;

[0162] S1022: For the second positioning block 1012, the number of reflection surfaces N of the multi-sided prism satisfies N = k×360 / α = 6k, where k is a positive integer. Therefore, considering the processing difficulty and cost of the multi-sided prism, a six-sided prism, a twelve-sided prism, or an eighteen-sided prism can be selected; rotate the multi-sided prism by k reflection surfaces (the corresponding k values for the six-sided prism, twelve-sided prism, and eighteen-sided prism are 1, 2, and 3), finely adjust the rotation angle of the multi-sided prism so that the reading of the photoelectric autocollimator is 0, fix the rotation angle of the multi-sided prism, and complete the correction of the second positioning block; use the same method to complete the correction of the third positioning block and the fourth positioning block.

[0163] Furthermore, to improve the accuracy when aligning the positioning block, step 2 includes using a dial indicator to correct the position degree of the positioning block, specifically including the following steps:

[0164] S201: Adjust the rotation angle of the horizontal rotary table, and approximately horizontally set the positioning block by visual judgment;

[0165] 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 in the horizontal plane, and finely adjust the angle of the positioning block according to the reading of the dial indicator until the change η of the reading of the dial indicator pointer is less than 1% when the dial indicator needle slides from one end to the other end on the positioning block, and determine that the positioning block is strictly horizontal.

[0166] 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 beneficial to obtaining a larger height difference at both ends of the top of the positioning block, enabling the dial indicator to have a larger reading change and obtaining a more sensitive signal.

[0167] In this embodiment, by setting a positioning block parallel to the built-in plane of the target hollow part, the angular relationship of the projection of the built-in plane of the target hollow part in the radial plane is converted into the angular relationship between the positioning blocks, so as to realize the positioning of the relative position relationship 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 included 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 degree of the positioning block, so as to realize the positioning of the absolute position relationship between the built-in planes of the target hollow part relative to the horizontal plane.

[0168] Embodiment 4

[0169] This embodiment discloses a processing method for a hollow part. Using the processing die described in Embodiment 1, as Figure 7 shown, in addition to Steps 1 and 2 in Embodiment 3, the following steps are further included:

[0170] A preprocessing process for the preformed hollow part blank is also included between Step 1 and Step 2;

[0171] A heat treatment process for the preformed hollow part blank is also included between the preprocessing process of the preformed hollow part blank and Step 2;

[0172] Step 3 is provided after Step 2: machining the aligned preformed hollow part blank to obtain the built-in plane.

[0173] Specifically, the preprocessing process of the preformed hollow part blank includes the following steps:

[0174] S104: Select a group of centrally symmetric first positioning through holes 105, take the center connection line of the two as the reference line of the first positioning block, and obtain the included angle α0 between the reference line and the first positioning block;

[0175] S105: Fix the preformed hollow part blank on the rotary worktable through the processing die, and obtain the inclination angle α of the reference line relative to the horizontal plane - , based on the included angle α0 and the angle α - obtain the rotation angle α of the rotary worktable required for aligning the first positioning block t1 ; based on α t1 complete the preliminary alignment of the first built-in plane; specifically, α t1 satisfies: α t1 =α - +90° - α0;

[0176] S106: Machine the machining die with a 0.2 mm allowance after the preliminary alignment of the first built-in plane is completed;

[0177] S107: Based on α t1The angle α1 between the first built-in plane and the second built-in plane is used to obtain the rotation angle α of the rotary table 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.

[0178] 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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] Specifically, the hollow part is made of titanium alloy.

[0184] 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:

[0185] S108: Heat-treat at 120 °C for 6 h, and then air-cool to room temperature.

[0186] S109: Treat at -50 °C for 2 h, and then place at room temperature to recover.

[0187] S110: Heat-treat at 120 °C for 6 h, and then air-cool or furnace-cool to room temperature.

[0188] Specifically, steps 3 and S106 - S107 for machining parts using a machine tool include the following steps:

[0189] S301: Using the x, y, z three-axis space coordinate system set by the machine tool itself, where the x-axis is set parallel to the horizontal plane, the y-axis is set parallel to the axial direction of the machined part, and the z-axis is set perpendicular to the horizontal plane, construct a three-dimensional model of the preformed hollow part blank and a three-dimensional model of the machined part finished product.

[0190] S302: Use programming software to compare the three-dimensional model of the preformed hollow part blank and the three-dimensional model of the machined part finished product to obtain the area to be machined F(x, y, z), and generate a machining program.

[0191] S303: Based on the machining program, machine the aligned part from the inside to the outside to obtain a finished part with corresponding internal planes.

[0192] As mentioned above, it is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A processing device for a hollow part, characterized in that, Comprising: An external pressing plate (1), a pull rod (2), a bottom fixing member (3), a vertical rotary table (5), a machine tool platform (6), a machine tool spindle (7), and a machining tool (8); The external pressing plate (1) is located at one end of the pull rod, and the bottom fixing member (3) is located at the other end of the pull rod (2). The external pressing plate (1) and the bottom fixing member (3) are fixedly connected by the pull rod (2). A fixing area for clamping and fixing a preformed hollow part blank is provided between the external pressing plate (1) and the bottom fixing member (3); Axial parallel planes are provided inside the hollow part. A positioning block (101) parallel to the built-in axial parallel plane is provided at one end of the external pressing plate (1) away from the bottom fixing member (3). A central hole (102) for the machining tool (8) to enter and exit is provided at the center of the external pressing plate (1). A solid area (103) is provided at the outer peripheral edge of the central hole (102) of the positioning block (101); The vertical rotary table (5) is fixedly connected to the end of the bottom fixing member (3) facing away from the external pressing plate (1); One side of the machine tool platform (6) is movably connected to the vertical rotary table (5), and the other side of the machine tool platform (6) is movably connected to the machine tool spindle (7); The machining tool (8) is provided at the end of the machine tool spindle (7) on the side close to the external pressing plate (1); One or more of the positioning blocks (101) are provided, corresponding one-to-one to the planes parallel to the built-in axis; The feed end of the machining device is provided with a coaxial rotating multi-faceted prism, and the angular relationship between the radial projections of the positioning blocks (101) is determined by the multi-faceted prism; The setting rule of the positioning block (101) is satisfied as follows: a first positioning block is set as the reference positioning block, and based on the angle between the M-th positioning block and the reference positioning block, the multi-faceted prism is rotated by k side faces to determine the position of the M-th positioning block relative to the reference positioning block, where k is a positive integer and k = α m / (360 / N), α m is the angle between the M-th positioning block and the reference positioning block, M is an integer greater than or equal to 3, 360 / N is the central angle corresponding to a single reflecting surface of the multi-faceted prism, and N is the number of reflecting surfaces of the multi-faceted prism.

2. The processing device according to claim 1, wherein The control program of the machining device includes: restricting the machining range of the machining tool (8) to a fixed area on one side of the center relative to the preformed hollow part blank.

3. The processing device according to claim 1, characterized in that, A pull rod mounting hole (104) provided at the edge of the body of the external pressing plate (1); One end of the pull rod (2) is provided with a thread, and the other end is fixedly connected to the bottom fixing member (3), and the thread matches the nut.

4. The processing device according to claim 3, characterized in that, The pull rod mounting hole (104), the pull rod (2), and the nut form a movable connection structure for adjusting the pressing degree of the external pressing plate (1) and the bottom fixing member (3) on the hollow part (4).

5. The processing device according to claim 1, characterized in that, The machining tool (8) selects a cemented carbide tool, satisfying: diameter 12mm - 20mm, chamfer radius 1mm - 3mm.

6. A processing method for a hollow part, characterized in that, Using the machining device according to any one of claims 1 - 5.

Images