Polyhedral high-precision turning method

Abstract

The application discloses a kind of polyhedral high-precision turning processing methods, belong to ultra-precision machining technical field, comprising: positioning datum surface is processed on polyhedral blank, obtain polyhedral with datum blank;With positioning datum surface as datum, polyhedral with datum blank is clamped and pose calibration for the first time, adopts slow knife servo turning mode and is turned, and the preformed profile of all target surfaces of polyhedral with datum blank is continuously turned under first clamping, and polyhedral preformed workpiece is obtained;With positioning datum surface as datum, polyhedral preformed workpiece is clamped for the second time, and each target surface to be processed is precisely machined using fly cutting method;Wherein, the precision machining of each target surface to be processed includes: based on positioning datum surface, adjust the position relationship between target surface to be processed and fly knife, after adjustment is completed, use fly knife to precisely machine target surface to be processed;The processing of all target surfaces is sequentially completed, and polyhedral finished workpiece is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyhedral ultra-precision machining, and particularly relates to a polyhedral high-precision turning machining method. BACKGROUND

[0002] With the development of high-performance imaging and beam shaping systems, higher requirements are put forward for the multi-surface optical element in terms of surface shape accuracy, surface roughness, position accuracy of each surface, and structural compactness. Such multi-surface optical elements require multiple surfaces with precise optical functions to be machined on the same substrate material, and the surfaces have strict spatial angle and position relationship (i.e., "position accuracy") between each other, and each single surface also needs to have extremely high surface shape accuracy and sub-nanometer surface roughness.

[0003] Various machining methods have been proposed for the high-precision manufacturing of multi-surface optical elements. In the prior art, patent CN117124483A discloses a high-precision compensation machining method for free-form surface prisms based on online and offline detection. The angles, positions and surface shape errors of each machined surface of the prism are detected by an optical contact probe and a three-coordinate measuring system, and compensation turning machining is performed according to the detection results to improve the overall machining accuracy of the free-form surface prism. Subsequently, patent CN118268812B proposes a machining method for multi-surface optical elements. By selecting one of the mirror surfaces as a reference, the remaining mirror surfaces are measured as a whole by combining with computer holographic compensation interferometry, and multi-round compensation turning is used to achieve multi-surface precision control. Further, patent CN119376057B discloses a shape and position reference element and a manufacturing method for multi-surface optical elements. A unified reference coordinate system is established by introducing a reference rod and a target ball, and the position and surface shape of the multi-surface optical element are detected in this coordinate system. Multi-round detection and iterative machining are used to achieve collaborative control of the multi-surface shape and position accuracy.

[0004] The above methods have made certain progress in the precision control of multi-surface optical elements, but as a whole, they still mainly rely on detection and compensation strategies, and pay less attention to the organization of different turning methods in the machining process.

[0005] In the processing of large inclination angle multi-faceted common body, two major challenges are mainly faced. One is that the position accuracy between multiple faces of the multi-faceted common body is difficult to guarantee. If a processing method of multiple clamping or multiple turning methods combination is adopted, the processing alignment error and the processing error are easy to be coupled and accumulated, and the common body is destroyed. The other is that the edge quality of the large inclination angle face is poor. In the large inclination angle multi-faceted structure, the angle between each processing face is large, and the existing method is difficult to consider the clamping positioning accuracy, the processing stability, and the face shape quality and surface roughness of the edge region of the large inclination angle face under the unified reference condition. When the edge region is processed, the tool movement direction changes sharply, and the traditional slow tool servo (STS) technology will generate a servo following error due to the inertia of the driving system, which causes the face shape of the edge region to collapse and the surface roughness to deteriorate, and further affects the overall performance of the multi-faceted common body optical element.

[0006] Therefore, an ultra-precision processing method suitable for large inclination angle multi-faceted common body optical elements is needed, which realizes the effective connection of the multi-stage processing process by reasonably organizing different processing methods under the unified reference condition, so as to improve the position accuracy between multiple faces of the multi-faceted body and ensure the processing quality of each face. SUMMARY

[0007] The purpose of the present application is to provide a multi-faceted high-precision turning processing method, which solves the problems of errors in the relative position and angle relationship between multiple faces of the large inclination angle multi-faceted common body optical element and poor face shape precision and edge quality of the single face of the large inclination angle multi-faceted common body in the prior art.

[0008] To achieve the above purpose, the present application provides a multi-faceted high-precision turning processing method, comprising the following steps:

[0009] S1: processing a positioning reference surface on the multi-faceted blank to obtain a multi-faceted reference blank;

[0010] S2: clamping and pose calibration of the multi-faceted reference blank by tooling with the positioning reference surface as the reference, and turning processing by slow tool servo turning method, to continuously turn the preformed profile of all target faces of the multi-faceted reference blank under the first clamping to obtain a multi-faceted preformed workpiece;

[0011] S3: clamping and pose calibration of the multi-faceted preformed workpiece by tooling with the positioning reference surface as the reference, and face-by-face finishing by fly cutting method to obtain a multi-faceted finished workpiece.

[0012] Preferably, the positioning reference surface comprises a cylindrical reference surface, a top reference surface and a side reference surface; the top reference surface and the side reference surface are perpendicular to each other, and the distance from the axis of the cylindrical reference surface to the top reference surface and the side reference surface is equal.

[0013] Preferably, between S1-S2, further comprising the step of: taking the positioning reference surface as the measurement reference, measuring the machining allowance of each target surface on the polyhedral reference blank offline.

[0014] Preferably, in S2, the tooling includes: a first base plate, a side support frame, a pressing plate, and a T-shaped positioning piece; the first base plate is a cylindrical flat base, and the first base plate is provided with a first type of connecting hole connected with the side support frame and a second type of connecting hole connected with the T-shaped positioning piece; the side support frame is an L-shaped corner seat, the bottom plate of the side support frame is connected with the first base plate through the first type of connecting hole, and the positioning vertical plate of the side support frame is positioned and clamped to the polyhedral reference blank through the top reference surface and the side reference surface of the polyhedral reference blank to determine the horizontal position thereof; the bottom positioning disc of the T-shaped positioning piece is connected with the base plate through the second type of connecting hole, the core shaft of the T-shaped positioning piece penetrates through the polyhedral reference blank along the through hole of the polyhedral reference blank in the axial direction, the T-shaped positioning piece is coaxial with the first base plate, and the top end of the core shaft is provided with a threaded hole for connecting with the pressing plate, and the polyhedral reference blank is fixed on the first base plate through the pressing plate.

[0015] Preferably, in S2, the first clamping and pose calibration of the polyhedral reference blank to the tooling with the positioning reference surface as the reference includes the following steps:

[0016] S21, assemble the polyhedral reference blank and the tooling into an integrated whole and clamp the integrated whole to the machine tool as a whole;

[0017] S22, taking the top reference surface and the cylindrical reference surface as the positioning reference, using a contact probe to touch and align the cylindrical reference surface, adjusting the position of the polyhedral reference blank to make the polyhedral rotation center coaxial with the machine tool spindle, and completing the pose calibration.

[0018] Preferably, between S2-S3, further comprising the step of: using a three-coordinate measuring machine to take the top reference surface, the side reference surface, and the cylindrical reference surface as the measurement reference to measure the machining allowance of each target surface on the polyhedral reference blank offline.

[0019] Preferably, in S3, the first base plate is arranged on a wedge-shaped seat, the first base plate is connected with the wedge-shaped seat through a second base plate, the second base plate is fixed on the wedge-shaped seat, the wedge-shaped seat is fixed on a workbench, the first base plate and the second base plate are locked and connected through screws or studs, and a plurality of adjusting structures are arranged between the first base plate and the second base plate.

[0020] Preferably, the adjusting structure includes a plurality of adjusting holes uniformly arranged on the first base plate, adjusting columns are threadedly connected in the adjusting holes, and the end of the adjusting column abuts against the surface of the second base plate close to the first base plate; the pose of the workpiece to be machined is adjusted by rotating the adjusting column.

[0021] Preferably, in S3, the pose of the surface to be processed is calibrated, comprising the following steps:

[0022] S31, clamping the polyhedral preform workpiece on the tooling;

[0023] S32, measuring the pitch angle and yaw angle of the surface to be processed by using a touch probe, rotating the adjusting column to make the pitch angle and yaw angle of the surface to be processed 0°, and processing the surface to be processed by the flying cutter;

[0024] S33, rotating the bolt to detach the pressing plate from the T-shaped positioning member, rotating the polyhedral preform workpiece to make the next surface to be processed in the flying cutter processing position; repeating S32 to process;

[0025] S34, repeating S33 to complete the finish machining of all surfaces to be processed of the polyhedral preform workpiece.

[0026] Preferably, the polyhedron is a tetrahedral structure.

[0027] The polyhedral high-precision turning method has the following advantages and positive effects:

[0028] 1. High commonality of multiple surfaces: the preform profile of all target surfaces is continuously machined under one clamping by slow tool servo, which fundamentally avoids error accumulation caused by multiple clamping and ensures the accuracy of the angle and position relationship between multiple target surfaces of the polyhedral workpiece.

[0029] 2. High machining precision of single target surface: on the basis of maintaining high position accuracy, each target surface is precisely machined by flying cutter turning technology, which effectively improves the surface shape precision of single target surface and reduces the surface roughness. Since each target surface is precisely machined by flying cutter, the edge quality of large-angle surface is effectively improved.

[0030] 3. High process stability: the unified reference system perfectly connects the two core processes (slow tool servo machining and flying cutter machining) and the two offline measurements, which has strong process stability and good repeatability.

[0031] 4. Balancing of machining efficiency and precision: slow tool servo enables rapid forming of the polyhedral workpiece, improving efficiency, and flying cutter precise finishing guarantees quality, which realizes the balance of efficiency and precision.

[0032] The technical solutions of the present application will be further described in detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The flowchart of the polyhedral high-precision turning method of the present application;

[0034] Figure 2 A workpiece structure schematic diagram of a polyhedral high-precision turning machining method of the present application;

[0035] Figure 3 A slow tool servo machining schematic diagram of a polyhedral high-precision turning machining method of the present application;

[0036] Figure 4 A slow tool servo machining side view of a polyhedral high-precision turning machining method of the present application;

[0037] Figure 5 A flying tool machining schematic diagram of a polyhedral high-precision turning machining method of the present application;

[0038] Figure 6 A flying tool machining side view of a polyhedral high-precision turning machining method of the present application;

[0039] Figure 7 A flying tool machining jig interface structure schematic diagram of a polyhedral high-precision turning machining method of the present application;

[0040] Figure 8 A jig structure schematic diagram of a polyhedral high-precision turning machining method of the present application.

[0041] Reference signs

[0042] 1, polyhedron; 2, machine tool; 3, top reference surface; 4, side reference surface; 5, cylindrical reference surface; 6, target surface; 7, first base plate; 8, side support frame; 9, pressing plate; 10, T-shaped positioning piece; 11, second base plate; 12, wedge-shaped seat; 13, bolt; 14, adjusting hole; 15, workbench. DETAILED DESCRIPTION

[0043] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "provided", "mounted", "connected" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0045] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0046] like Figure 1 As shown, a method for high-precision turning of polyhedra includes the following steps:

[0047] S1: Machining a positioning reference surface on polyhedron 1 blank to obtain polyhedron 1 blank with reference.

[0048] The positioning reference planes include a cylindrical reference plane 5, a top reference plane 3, and a side reference plane 4; the top reference plane 3 and the side reference plane 4 are perpendicular to each other, and the distance from the axis of the cylindrical reference plane 5 to the top reference plane 3 and the side reference plane 4 is equal.

[0049] Between S1 and S2, the following steps are also included: using the positioning reference plane as the measurement reference, the machining allowance of each target surface 6 on the polyhedron 1 with reference blank is measured offline.

[0050] S2: As Figure 3 , Figure 4 As shown, the polyhedron 1 with reference blank is clamped and calibrated for the first time using a tooling with the positioning reference surface as the reference. The turning process is carried out by slow tool servo turning. Under the first clamping, the pre-formed contours of all target surfaces 6 of the polyhedron 1 with reference blank are continuously turned to obtain the pre-formed workpiece of the polyhedron 1.

[0051] like Figure 7 , Figure 8 As shown, the tooling includes a first base 7, a side support frame 8, a pressure plate 9, and a T-shaped positioning component 10. The first base 7 is a cylindrical flat base with a first type of connection hole for connecting to the side support frame 8 and a second type of connection hole for connecting to the T-shaped positioning component 10. The side support frame 8 is an L-shaped corner seat. The bottom plate of the side support frame 8 is connected to the first base 7 through the first type of connection hole. The positioning plate of the side support frame 8 positions and clamps the polyhedron 1 with reference blank through the top reference surface 3 and the side reference surface 4 of the polyhedron 1 with reference blank to determine its horizontal position. The bottom positioning plate of the T-shaped positioning component 10 is connected to the base through the second type of connection hole. The mandrel of the T-shaped positioning component 10 has a through hole along the axis of the polyhedron 1 with reference blank, and the T-shaped positioning component 10 is coaxial with the first base 7. The top of the mandrel is provided with a threaded hole for connecting to the pressure plate 9. The pressure plate 9 fixes the polyhedron 1 with reference blank on the first base 7.

[0052] The first clamping and pose calibration of the polyhedron 1 reference blank through the tooling based on the positioning reference surface includes the following steps:

[0053] S21, assemble the polyhedron 1 reference blank and the tooling into one body, and clamp the whole to the machine tool 2;

[0054] S22, use the contact probe to touch and align the cylindrical reference surface 5 with the top reference surface 3 as the positioning reference, adjust the position of the polyhedron 1 reference blank, so that the rotation center of the polyhedron 1 is coaxial with the spindle of the machine tool 2, and complete the pose calibration.

[0055] Between S2-S3, also includes the step: using a three-coordinate measuring machine to measure the machining allowance of each target surface 6 on the polyhedron 1 reference blank based on the top reference surface 3, side reference surface 4 and cylindrical reference surface 5 as the measurement reference.

[0056] S3: as shown in Figure 5 、 Figure 6 , the second clamping of the polyhedron 1 preformed workpiece through the tooling based on the positioning reference surface, the pose calibration of the machined surface, the fly cutting method is used to process each surface to obtain the finished polyhedron 1 workpiece.

[0057] The first chassis 7 is arranged on the wedge-shaped seat 12, and the first chassis 7 is connected with the wedge-shaped seat 12 through the second chassis 11, the second chassis 11 is fixed on the wedge-shaped seat 12, the wedge-shaped seat 12 is fixed on the workbench 15, the first chassis 7 and the second chassis 11 are locked and connected through screws or studs, and a plurality of adjusting structures are arranged between the first chassis 7 and the second chassis 11.

[0058] The adjusting structure includes a plurality of adjusting holes 14 uniformly arranged on the first chassis 7, and an adjusting column is threadedly connected in the adjusting hole 14, and the end of the adjusting column abuts against the surface of the second chassis 11 close to the first chassis 7; the pose of the workpiece machined surface is adjusted by rotating the adjusting column.

[0059] The pose calibration of the machined surface includes the following steps:

[0060] S31, clamp the polyhedron 1 preformed workpiece on the tooling;

[0061] S32, measure the pitch angle and yaw angle of the machined surface by using the touch probe, rotate the adjusting column to make the pitch angle and yaw angle of the machined surface 0°, and process the machined surface by the fly cutter;

[0062] S33, rotate the bolt 13 to detach the pressing piece 9 from the T-shaped positioning piece 10, rotate the polyhedron 1 preformed workpiece, and place the next machined surface in the fly cutter processing position; repeat S32 to process.

[0063] S34, repeat S33 to complete the finishing of all surfaces to be machined of the polyhedral 1 preform workpiece.

[0064] The method described in the present application will be described in more detail below in connection with a tetrahedron. The tetrahedron structure is shown in Figure 2

[0065] It should be noted that the tetrahedron has different forms as the processing steps proceed: we call the form of the tetrahedron at the beginning the tetrahedron blank, the form after the machining of the reference surface the tetrahedron blank with reference, the form after the slow tool servo turning the tetrahedron preform workpiece, and the form after the fly cutting the polyhedral finished workpiece.

[0066] The specific steps are as follows:

[0067] Step 1: clamp the tetrahedron blank on the single-point diamond lathe, machine three types of positioning reference surfaces of the tetrahedron blank, including the top reference surface 3, the side reference surface 4, and the cylindrical reference surface 5; wherein the top reference surface 3 and the side reference surface 4 satisfy the geometric relationship of mutual perpendicularity, and the axis of the cylindrical reference surface 5 has an equidistance relationship with the top reference surface 3 and the side reference surface, machine the tetrahedron blank into the tetrahedron blank with reference to establish a unified clamping and measuring reference.

[0068] Step 2: disassemble the tetrahedron blank with reference from the machine tool, use a three-coordinate measuring machine to measure the machining allowance of the four target surfaces offline with the top reference surface 3, the side reference surface 4, and the cylindrical reference surface 5 as the measuring reference to obtain the allowance distribution data.

[0069] Step 3: design and manufacture a slow tool servo machining clamp according to the structural characteristics of the tetrahedron blank, the slow tool servo machining clamp includes a first chassis 7, a side support frame 8, and a T-shaped positioning piece 10, for realizing stable support and repeated positioning of the blank.

[0070] Step 4: assemble the tetrahedron blank with reference and the slow tool servo machining clamp into one body, and clamp the whole body to the machine tool 2.

[0071] Step 5: in the three-dimensional coordinate system (X-Y-Z) of the machine tool, take the top reference surface 3 and the cylindrical reference surface 5 as the positioning reference; use a contact probe to touch and align the cylindrical reference surface 5, adjust the workpiece rotation center and the C-axis of the machine tool to realize coaxiality, the C-axis of the machine tool is the main shaft of the machine tool, and the C-axis is located on the Z-axis of the three-dimensional coordinate system; then use the contact probe to measure the top reference surface 3, and correct the pitch angle a of the top reference surface 3 and the zero position γ offset around the C-axis to complete the workpiece pose calibration.

[0072] ​Specifically, the contact probe is used to measure and correct the pitch angle a and the zero position γ offset around the C axis of the top reference surface 3, so that the pitch angle a and the zero position γ are 0, and the workpiece pose calibration is completed.

[0073] Step 6: According to the tetrahedron target geometry, a turning tool path is generated, and a slow tool servo method is used for pre-form turning of the tetrahedron reference blank in one clamping condition, so that the pre-form contour of the four target surfaces of the tetrahedron reference blank is continuously turned, and a tetrahedron pre-form workpiece is obtained.

[0074] Step 7: The tetrahedron pre-form workpiece is detached from the machine tool, and the three-coordinate measuring machine is used to measure the remaining machining allowance of the four target surfaces 6 with the top reference surface 3, the side reference surface, and the cylindrical reference surface 5 as the measurement reference.

[0075] Step 8: The tetrahedron pre-form workpiece is assembled with the tooling as a whole and clamped to the worktable 15 as a whole.

[0076] Step 9: The four target surfaces of the tetrahedron pre-form workpiece are processed by surface precision turning: the target surface to be processed is selected for processing, the contact probe is used to measure and correct the pitch angle a and the yaw angle β of the target surface to be processed, and the target surface to be processed is adjusted in position to complete the precision turning of the target surface to be processed; the tetrahedron pre-form workpiece is indexed and rotated around the cylindrical axis of the T-shaped positioning member 10, so that the target surface to be processed is sequentially in the fly cutting position; then the same alignment and precision turning process is repeated to sequentially complete the precision turning of the remaining three surfaces, thereby realizing high-precision turning forming of the four surfaces of the tetrahedron, and obtaining a tetrahedron finished workpiece.

[0077] Specifically, the contact probe is used to measure and correct the pitch angle a and the yaw angle β of the target surface to be processed, so that the pitch angle and the yaw angle are 0, and the target surface to be processed is completely perpendicular to the fly cutter, facilitating the fine processing of the target surface to be processed by the fly cutter.

[0078] Therefore, the polyhedral high-precision turning method of the present application perfectly connects the two core processes (slow tool servo processing and fly cutter processing) under a unified reference system, and solves the problems of errors in the relative position and angle relationship between multiple surfaces in the large-inclination multi-surface optical element, and poor surface shape precision and edge quality of a single surface in the large-inclination multi-surface optical element.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method of polyhedral high-precision turning, characterized by, The method comprises the following steps: S1: machining a positioning reference surface on the polyhedral blank to obtain a polyhedral blank with reference; S2: taking the positioning reference surface as a reference, clamping and calibrating the polyhedral blank with reference through a tooling for the first time, adopting a slow tool servo turning mode to turn, and continuously turning all target surfaces of the polyhedral blank with reference to obtain a polyhedral preformed workpiece; S3: taking the positioning reference surface as a reference, clamping the polyhedral preformed workpiece through a tooling for the second time, calibrating the position and posture of the surface to be machined, and adopting a flying tool cutting mode to finish machining each surface to obtain a polyhedral finished workpiece; In S2, the tooling comprises a first base plate, a side support frame, a pressing plate, and a T-shaped positioning member; the first base plate is a cylindrical flat base, and the first base plate is provided with a first type of connecting hole connected with the side support frame and a second type of connecting hole connected with the T-shaped positioning member; the side support frame is an L-shaped corner seat, the bottom plate of the side support frame is connected with the first base plate through the first type of connecting hole, and the positioning vertical plate of the side support frame is clamped and fixed to the polyhedral blank with reference through the top reference surface and the side reference surface of the polyhedral blank with reference to determine the horizontal position thereof; the bottom positioning disc of the T-shaped positioning member is connected with the base plate through the second type of connecting hole, the core shaft of the T-shaped positioning member penetrates through the polyhedral blank with reference along the through hole in the axial direction of the polyhedral blank with reference, the T-shaped positioning member is coaxial with the first base plate, the top end of the core shaft is provided with a threaded hole used for connecting with the pressing plate, and the polyhedral blank with reference is fixed on the first base plate through the pressing plate; In S3, the first base plate is arranged on a wedge-shaped seat, the first base plate is connected with the wedge-shaped seat through a second base plate, the second base plate is fixed on the wedge-shaped seat, the wedge-shaped seat is fixed on a workbench, the first base plate and the second base plate are locked and connected through screws or studs, and a plurality of adjusting structures are arranged between the first base plate and the second base plate; The adjusting structure comprises a plurality of adjusting holes uniformly arranged on the first base plate, and an adjusting column is threadedly connected in the adjusting hole, and the end of the adjusting column abuts against the surface of the second base plate close to the first base plate; the position and posture of the workpiece surface to be machined are adjusted by rotating the adjusting column.

2. The polyhedral high-precision turning method according to claim 1, characterized in that, The positioning reference surface comprises a cylindrical reference surface, a top reference surface, and a side reference surface; the top reference surface and the side reference surface are perpendicular to each other, and the distance from the axis of the cylindrical reference surface to the top reference surface and the side reference surface is equal.

3. The method of claim 1, wherein the polyhedral high-precision turning process is characterized by, Between S1 and S2, the method further comprises the step of: taking the positioning reference surface as a measurement reference to measure the machining allowance of each target surface of the polyhedral blank with reference offline.

4. The polyhedral high-precision turning method according to claim 1, wherein In S2, the first clamping and position and posture calibration of the polyhedral blank with reference through the tooling with the positioning reference surface as a reference comprises the following steps: S21: assembling the polyhedral blank with reference and the tooling into an integrated whole and clamping the integrated whole to a machine tool as a whole; S22: taking the top reference surface and the cylindrical reference surface as positioning references, adopting a contact probe to touch and find the cylindrical reference surface, adjusting the position of the polyhedral blank with reference, and making the polyhedral rotation center coaxial with the machine tool spindle to complete the position and posture calibration.

5. The method of claim 1, wherein the polyhedral high-precision turning process is characterized by, Between S2-S3, further comprising the steps of: using a three-coordinate measuring machine to take the top reference surface, side reference surface and cylindrical reference surface as the measurement reference to measure the machining allowance of each target surface on the polyhedral reference blank off-line.

6. The method of claim 1, wherein the polyhedral high-precision turning process is characterized by, In the S3, the pose of the surface to be machined is calibrated, comprising the following steps: S31, clamping the polyhedral preformed workpiece on the tooling; S32, measuring the pitch angle and yaw angle of the surface to be machined by using a touch probe, rotating the adjusting column to make the pitch angle and yaw angle of the surface to be machined 0°, and machining the surface to be machined by a flying cutter; S33, rotating the bolt to detach the pressing piece from the T-shaped positioning member, rotating the polyhedral preformed workpiece to make the next surface to be machined in the flying cutter machining position; repeating S32 to machine; S34, repeating S33 to complete the finish machining of all the surfaces to be machined of the polyhedral preformed workpiece.

7. The method of claim 1, wherein: the polyhedron is a tetrahedron. The polyhedron is a tetrahedron structure.

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