A method for processing stepped deep holes

Abstract

A method for processing stepped deep holes belongs to the field of CNC processing. When processing stepped deep holes, the small hole drill bit is bent by force, and the torsional combined torque is large, resulting in poor coaxiality between the drilled large hole and the small hole, and large roughness of the inner wall surface of the drilled hole. The deep hole is processed in sections and on both sides, that is, the large diameter hole on one side of the workpiece is processed first, the workpiece is turned over and aligned, and then the small diameter hole on the other side of the workpiece is processed. This processing method can, on the one hand, reduce the length of the deep hole processing tool and avoid the problem of poor processing accuracy caused by the excessive length of the processing tool during the deep hole processing process, while ensuring the coaxiality of the two deep holes; on the other hand, when the large diameter hole is processed first and the small diameter hole is processed again, it is beneficial to the flow of coolant to achieve sufficient cooling and chip removal of the workpiece. The present invention is mainly used for stepped deep hole processing.

Description

Technical Field

[0001] The invention belongs to the field of numerical control machining, and in particular relates to a method for machining stepped deep holes. Background Art

[0002] Drilling of workpieces is generally completed by a drill bit. For deep holes with steps, a large-diameter hole is usually drilled first with a large-hole drill bit, and then a small-hole drill bit is inserted into the large hole and drilled out a small hole. This requires lengthening the small-hole drill bit. Generally, the length-to-diameter ratio of a large-hole drill bit is 7.5, while that of a small-hole drill bit is 18.67. When drilling with a small-hole drill bit, the small-hole drill bit is bent by force, and the torsional combined torque is large, resulting in poor coaxiality between the drilled large hole and the small hole, large roughness of the inner wall of the drilled hole, insufficient cooling, difficulty in chip removal, and poor overall drilling accuracy. Summary of the Invention

[0003] In view of this, the present invention provides a method for machining a stepped deep hole, which can ensure the coaxiality and low roughness of the inner wall surface of the stepped deep hole and improve the machining accuracy of the stepped deep hole.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] A method for machining a stepped deep hole, wherein the stepped deep hole of a workpiece comprises at least two sequentially connected and coaxial deep holes. The machining of the stepped deep hole is achieved using a CNC five-axis linkage machine tool, which is provided with a worktable for clamping the workpiece. The specific machining process is as follows:

[0006] S1, use 3D modeling software to model and program the workpiece, and import the compiled program into the CNC five-axis linkage machine tool;

[0007] S2, clamping the workpiece on the worktable and leveling it;

[0008] S3, workpiece alignment;

[0009] S4, using a deep hole machining tool to machine the first deep hole on the upper plane of the workpiece, and setting it as deep hole one;

[0010] S5, when the first deep hole 1 is processed, the work disk is rotated and step 4 is repeated to process the next deep hole 1 until all deep holes 1 are processed;

[0011] S6, machining two symmetrically arranged standard holes on the center plane of the workpiece to serve as alignment holes after the workpiece is turned over;

[0012] S7, flip the workpiece, clamp the workpiece on the workpiece plate again and level it;

[0013] S8, align the workpiece using two aligning holes;

[0014] S9, using a deep hole processing tool to process the first deep hole of the flip surface, and setting it as deep hole 2;

[0015] S10, when the first deep hole 2 is processed, the work disk is rotated and step 9 is repeated to process the next deep hole 2 until all deep holes 2 are processed.

[0016] Preferably, the CNC five-axis linkage machine tool further includes a machine tool probe, and the S3 includes the following steps:

[0017] S31, draw the alignment center line along the diameter direction on the upper plane of the workpiece, and rotate the work disk until the alignment center line on the workpiece is aligned with the x-axis of the workpiece coordinate system on the vertical plane. At this time, the C-axis alignment is completed;

[0018] S32, measuring at least three coordinate values ​​of the outer cylindrical surface of the workpiece using a machine tool probe, and determining the center of the workpiece based on the at least three coordinate values;

[0019] S33, using the machine tool probe to contact the upper plane of the workpiece, determine the position of the contact point in the workpiece coordinate system, and thus determine the position of the upper plane of the workpiece in the workpiece coordinate system.

[0020] Preferably, in S4, when the deep hole 1 is a straight hole, the deep hole processing tool includes a drill bit 1, a drill bit 2, and a reamer 1. Assuming that the target hole diameter of the deep hole 1 is d, the diameter of the drill bit 1 is d2, the diameter of the drill bit 2 is d3, and the diameter of the reamer 1 is d4, wherein d2=d3<d4=d; S4 includes the following steps:

[0021] S41, aligning the drill bit 1 with the upper plane of the workpiece to be processed and drilling to obtain a guide hole 1;

[0022] S42, the drill bit 2 is inserted into the guide hole 1 and drills to a target depth to obtain the drill hole 1;

[0023] S43, reamer one is inserted into drill hole one and the hole is expanded to a target inner diameter to obtain a target deep hole one.

[0024] Preferably, in S4, when the deep hole 1 is a deep inclined hole, the deep hole processing tools include a drill bit 1, a drill bit 2, a milling cutter 1, and a reamer 1. Assuming that the target hole diameter of the deep inclined hole 1 is d, the diameter of the milling cutter 1 is d1, the diameter of the drill bit 1 is d2, the diameter of the drill bit 2 is d3, and the diameter of the reamer 1 is d4, wherein d1 < d2 = d3 < d4 = d; S4 includes the following steps:

[0025] S41, the milling cutter 1 is aligned with the position of the inclined hole to be machined on the workpiece, and a plane 1 for centering the inclined drilling is machined;

[0026] S42, the drill bit 1 is inserted into the plane 1 and drills a hole to obtain the guide hole 1;

[0027] S43, the drill bit 2 is inserted into the guide hole 1 and drilled obliquely to the target depth to obtain the drill hole 1;

[0028] S44, reamer one is inserted into drill hole one and the hole is expanded to a target inner diameter to obtain a target deep inclined hole one.

[0029] Preferably, when the deep hole is divided into three sections, after deep hole one is processed, the deep hole processing tool is sequentially inserted into deep hole one and processes the middle section deep hole until all the middle section deep holes are processed.

[0030] Preferably, the step S8 comprises the following steps:

[0031] S81, using a machine tool probe to measure at least three coordinate values ​​of the inner wall surfaces of the two alignment holes, and determining the center point of each alignment hole based on the at least three coordinate values, determining an alignment center line based on the center points of the two alignment holes, and rotating the worktable so that the alignment center line is aligned with the x-axis in the workpiece coordinate system in the vertical plane, and at this time, there is no deviation in the C-axis direction before and after the workpiece is flipped;

[0032] S82, measuring at least three coordinate values ​​of the outer cylindrical surface of the workpiece using a machine tool probe, and determining the center of the workpiece based on the at least three coordinate values, thereby determining the center of the workpiece coordinate system;

[0033] S83, taking the upper plane of the workpiece before flipping as a machining reference, and determining the position of the machining surface of the workpiece in the workpiece coordinate system.

[0034] Preferably, in S7, a three-jaw chuck is used to clamp and fix the workpiece, and in S83, a machine tool probe is used to contact the contact surface between the three-jaw chuck and the upper plane of the workpiece before flipping, to determine the position of the contact surface in the workpiece coordinate system, thereby determining the position of the machining surface of the workpiece in the workpiece coordinate system.

[0035] Preferably, in the above-mentioned S83, the position of the machined surface after the workpiece is flipped in the workpiece coordinate system is determined based on the thickness of the workpiece and the coordinate values ​​of the upper plane of the workpiece before flipping.

[0036] Preferably, in S9, when the deep hole is a straight hole, the deep hole processing tools include drill bit 3, drill bit 4, and reamer 2. Assuming that the target hole diameter of deep hole 2 is d', the diameter of drill bit 3 is d'2, the diameter of drill bit 4 is d'3, and the diameter of reamer 2 is d'4, wherein d'2=d'3<d'4=d'; S9 includes the following steps:

[0037] S91, drill bit 3 is aligned with the flip surface of the workpiece to be processed and drills a hole to obtain a second guide hole;

[0038] S92, the drill bit 4 is inserted into the guide hole 2 and drilled to the target depth to obtain the drill hole 2;

[0039] S93, the second reamer is inserted into the second drill hole and expanded to the target inner diameter to obtain the second target deep hole.

[0040] Preferably, in S9, when the deep hole is a deep inclined hole, the deep hole processing tools include drill bit 3, drill bit 4, milling cutter 2 and reamer 2, assuming that the target hole diameter of the deep inclined hole 2 is d', the diameter of the milling cutter 2 is d'1, the diameter of the drill bit 3 is d'2, the diameter of the drill bit 4 is d'3, and the diameter of the reamer 2 is d'4, wherein d'1 < d'2 = d'3 < d'4 = d'; S9 includes the following steps:

[0041] S91, the second milling cutter is aligned with the position of the oblique hole to be machined on the workpiece, and a second plane for centering the oblique drilling is machined;

[0042] S92, the drill bit 3 is inserted into the plane 2 and drilled to obtain the pilot hole 2;

[0043] S93, the drill bit 4 is inserted into the guide hole 2 and drilled obliquely to the target depth to obtain the drill hole 2;

[0044] S94, the second reamer is inserted into the second drill hole and expanded to the target inner diameter to obtain the target deep inclined hole second.

[0045] The beneficial effects of the present invention compared with the prior art are:

[0046] Because the overall depth of a stepped deep hole is relatively large, the deep hole is processed in sections and from both sides. That is, the large-diameter hole on one side of the workpiece is first processed, and then the workpiece is flipped and aligned before the small-diameter hole on the other side is processed. This processing method, on the one hand, can reduce the length of the deep hole processing tool, avoiding the problem of poor processing accuracy caused by the excessive length of the processing tool during deep hole processing, while also ensuring the coaxiality of the two deep holes. On the other hand, when the large-diameter hole is processed first and then the small-diameter hole is processed, it is conducive to the flow of coolant to achieve sufficient cooling of the workpiece and chip removal. In addition, each deep hole processing is carried out in at least three steps: drilling a guide hole, drilling a deep hole, and reaming the hole. This design can improve the processing accuracy of the deep hole, that is, ensure the shape, position and size requirements of the deep hole, and reduce the roughness of the stepped deep hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are incorporated in and constitute a part of this application and are used to provide a further understanding of the present invention.

[0048] Figure 1 This is a schematic structural diagram of the central nozzle flange in Example 1 of the present invention.

[0049] Figure 2 This is a schematic diagram of the workpiece being mounted on the work plate via a three-jaw chuck.

[0050] Figure 3 Schematic diagram of milling cutter 1 machining plane 1 for centering inclined drilling when machining deep inclined holes, where (a) is a schematic diagram of the milling cutter 1 machining process, and (b) is a schematic diagram of the milling cutter 1 after machining is completed and plane 1 is formed on the workpiece surface.

[0051] Figure 4 Schematic diagram of drill bit 1 machining guide hole 1 when machining a deep inclined hole, where (a) is a schematic diagram of the drill bit 1 machining process, and (b) is a schematic diagram of the drill bit 1 after machining is completed and guide hole 1 is formed on the workpiece surface.

[0052] Figure 5 Schematic diagram of drill bit 2 machining hole 1 when machining a deep inclined hole, where (a) is a schematic diagram of the machining process of drill bit 2, and (b) is a schematic diagram of the drill bit 2 after machining is completed and hole 1 is formed in the workpiece.

[0053] Figure 6 Schematic diagram of reamer 1 machining a target deep inclined hole 1 when machining a deep inclined hole, wherein (a) is a schematic diagram of the machining process of reamer 1, and (b) is a schematic diagram of reamer 1 after machining is completed and the target deep inclined hole 1 is formed in the workpiece.

[0054] Figure 7 Schematic diagram of two standard holes machined on the workpiece.

[0055] Figure 8 This is a schematic diagram of the workpiece being mounted on the work plate by a three-jaw chuck after being flipped.

[0056] Figure 9 Schematic diagram of milling cutter 2 machining plane 2 for centering inclined drilling when machining deep inclined holes, where (a) is a schematic diagram of the milling cutter 2 machining process, and (b) is a schematic diagram of the milling cutter 2 after machining is completed and plane 2 is formed on the workpiece surface.

[0057] Figure 10 Schematic diagram of drill bit 3 machining guide hole 2 when machining a deep inclined hole, where (a) is a schematic diagram of the machining process of drill bit 3, and (b) is a schematic diagram of the guide hole 2 formed on the workpiece surface after drill bit 3 is completed.

[0058] Figure 11 This is a schematic diagram of drill bit 4 processing hole 2 when machining a deep inclined hole.

[0059] Figure 12 This is a schematic diagram of reamer two machining the target deep inclined hole two when machining a deep inclined hole.

[0060] Explanation of the accompanying numbers: 1-working disk; 2-three-jaw chuck; 3-workpiece; 31-round table one; 32-round table two; 4-drill bit one; 5-drill bit two; 6-milling cutter one; 7-reamer one; 8-plane one; 9-guide hole one; 10-drill hole one; 11-target deep hole one; 12-standard hole; 13-drill bit three; 14-drill bit four; 15-milling cutter two; 16-reamer two; 17-plane two; 18-guide hole two; 20-target deep hole two. DETAILED DESCRIPTION

[0061] The present invention is described in detail below with reference to specific embodiments.

[0062] This embodiment provides a method for machining a stepped deep hole. The stepped deep hole of the workpiece 3 includes at least two sequentially connected and coaxial deep holes. The deep hole can be a deep straight hole or a deep inclined hole. The machining of the stepped deep hole is achieved by using a CNC five-axis linkage machine tool. The CNC five-axis linkage machine tool is provided with a worktable 1 and a three-jaw chuck 2 for clamping the workpiece 3, as well as a ruby ​​machine tool probe. Figures 1 to 12 , is the processing process of processing two deep holes. The specific processing process is as follows:

[0063] S1, using 3D modeling software, such as CAD / CAM software, to model and program the workpiece, and then import the compiled program into the CNC five-axis linkage machine tool;

[0064] S2, such as Figure 2 As shown, the three-jaw chuck 2 is fixed at the center of the work disk 1 of the CNC five-axis linkage machine tool, the upper surface of the three-jaw chuck 2 is leveled, and the error is controlled within 0.02mm. The three-jaw chuck 2 clamps and fixes the workpiece 3 to fix the workpiece 3 on the work disk 1, and the horizontality of the upper surface of the workpiece 3 is remeasured to control its error within 0.02mm to achieve leveling of the center nozzle flange;

[0065] S3, workpiece 3 alignment, the specific steps are as follows:

[0066] S31: Draw an alignment center line on the upper plane of the workpiece 3 along the diameter direction, and rotate the work disk 1 until the alignment center line on the workpiece 3 is vertically aligned with the X-axis in the workpiece coordinate system. At this time, the C-axis alignment is completed.

[0067] S32, using a ruby ​​probe of a CNC five-axis linkage machine tool to measure four coordinate values ​​of the outer cylindrical surface of the workpiece 3, and determining the center of the workpiece 3 based on the four coordinate values, thereby determining the center of the workpiece coordinate system;

[0068] S33, using a ruby ​​probe of a CNC five-axis linkage machine tool to contact the upper plane of the workpiece 3, and determining the position of the contact point in the workpiece coordinate system, thereby determining the position of the upper plane of the workpiece 3 in the workpiece coordinate system;

[0069] S4, using a deep hole machining tool to machine the first deep hole on the upper plane of the workpiece, and set it as deep hole 1. Since the machining methods of straight holes and inclined holes are slightly different, they are explained separately:

[0070] When the deep hole 1 is a straight hole, the deep hole processing tools include a drill bit 1, a drill bit 2, and a reamer 1. Assuming that the target hole diameter of the deep hole 1 is d, the diameter of the drill bit 1 is d2, the diameter of the drill bit 2 is d3, and the diameter of the reamer 1 is d4, wherein d2=d3<d4=d; S4 includes the following steps:

[0071] S41, aligning the drill bit 1 with the upper plane of the workpiece to be processed and drilling to obtain a guide hole 1;

[0072] S42, the drill bit 2 is inserted into the guide hole 1 and drills to a target depth to obtain the drill hole 1;

[0073] S43, reamer one is inserted into drill hole one and the hole is expanded to a target inner diameter to obtain a target deep hole one.

[0074] When the deep hole 1 is a deep inclined hole, Figures 3 to 6 As shown, a deep hole processing tool is used to process the first section of a deep inclined hole on the plane of a workpiece 3, and is set as deep inclined hole 1. The deep hole processing tool includes a drill bit 1 4, a drill bit 2 5, a milling cutter 1 6, and a reamer 1 7. Assuming that the target hole diameter of the deep inclined hole 1 is d, the diameter of the milling cutter 1 6 is d1, the diameter of the drill bit 1 4 is d2, the diameter of the drill bit 2 5 is d3, and the diameter of the reamer 1 7 is d4, wherein d1 < d2 = d3 < d4 = d. The specific processing process is as follows:

[0075] S41, the milling cutter 6 is aligned with the position of the oblique hole to be machined on the workpiece 3, and a plane 8 is machined for centering the oblique drilling;

[0076] S42, the drill bit 4 is inserted into the plane and drilled to obtain a guide hole 9 with a depth of 5 mm;

[0077] S43, inserting the carbide drill bit 5 into the guide hole 9 and drilling obliquely to the target depth to obtain the drill hole 10;

[0078] S44, a reamer 7 is inserted into the drill hole 10 and expanded to a target inner diameter to obtain a target deep hole 11;

[0079] S5, when the first deep hole 1 is processed, the work disk 1 is rotated and step 4 is repeated to process the next deep hole 1 until all deep holes 1 are processed;

[0080] S6, such as Figure 7As shown, two symmetrically arranged standard holes 12 are machined on the mid-plane of the workpiece 3 to serve as alignment holes after the workpiece 3 is flipped, ensuring that there is no deviation in the C-axis direction of the workpiece 3 before and after flipping;

[0081] S7, such as Figure 8 As shown, the three-jaw chuck 2 is flipped over and fixed at the center of the work plate 1 of the CNC five-axis linkage machine tool. The contact surface between the three-jaw chuck 2 and the workpiece 3 is leveled, and the error is controlled within 0.02mm. The workpiece 3 is flipped over and clamped and fixed by the three-jaw chuck 2. The horizontality of the upper surface of the workpiece 3 before flipping is remeasured, and the error is controlled within 0.02mm.

[0082] S8, using the two alignment holes to align the workpiece 3, the specific process is as follows:

[0083] S81, using a ruby ​​probe of a CNC five-axis linkage machine tool, respectively measure at least three coordinate values ​​of the inner wall surfaces of the two alignment holes, and determine the center point of each alignment hole based on the at least three coordinate values. Determine an alignment center line based on the center points of the two alignment holes, and rotate the work disk 1 so that the alignment center line is aligned with the x-axis in the workpiece coordinate system in the vertical plane. At this time, there is no deviation in the C-axis direction of the workpiece 3 before and after flipping.

[0084] S82, measuring at least three coordinate values ​​of the outer cylindrical surface of the workpiece 3 using a machine tool probe, and determining the center of the workpiece 3 based on the at least three coordinate values, thereby determining the center of the workpiece coordinate system;

[0085] S83, using the upper plane of the workpiece 3 before flipping as a machining reference, and determining the position of the machined surface of the workpiece 3 in the workpiece coordinate system; specifically, using a machine tool probe to contact the contact surface between the three-jaw chuck 2 and the upper plane of the workpiece 3 before flipping, to determine the position of the contact surface in the workpiece coordinate system, thereby determining the position of the machined surface of the workpiece 3 in the workpiece coordinate system; alternatively, determining the position of the machined surface of the workpiece 3 after flipping in the workpiece coordinate system based on the thickness of the workpiece 3 and the coordinate values ​​of the upper plane of the workpiece 3 before flipping;

[0086] S9, use the deep hole processing tool to process the first deep hole of the flip surface and set it as deep hole 2. Since the processing methods of straight holes and inclined holes are slightly different, they are explained separately:

[0087] When the deep hole is a straight hole, the deep hole processing tools include drill bit 3, drill bit 4, and reamer 2. Assuming that the target hole diameter of deep hole 2 is d', the diameter of drill bit 3 is d'2, the diameter of drill bit 4 is d'3, and the diameter of reamer 2 is d'4, where d'2=d'3<d'4=d'; S9 includes the following steps:

[0088] S91, drill bit 3 is aligned with the flip surface of the workpiece to be processed and drills a hole to obtain a second guide hole;

[0089] S92, the drill bit 4 is inserted into the guide hole 2 and drilled to the target depth to obtain the drill hole 2;

[0090] S93, the second reamer is inserted into the second drill hole and expanded to the target inner diameter to obtain the second target deep hole.

[0091] like Figures 9 to 12 As shown, when the deep hole is a deep inclined hole, a deep hole processing tool is used to process the first section of the inclined hole of the flip surface. The deep hole processing tool includes a third drill bit 13, a fourth drill bit 14, a second milling cutter 15 and a second reamer 16. Assuming that the target hole diameter of the deep hole 2 is d', the diameter of the second milling cutter 15 is d'1, the diameter of the third drill bit 13 is d'2, the diameter of the fourth drill bit 14 is d'3, and the diameter of the second reamer 16 is d'4, wherein d'1 < d'2 = d'3 < d'4 = d'; the specific process is as follows:

[0092] S91, the second milling cutter 15 is aligned with the position of the oblique hole to be machined on the workpiece 3, and a second plane 17 for centering the oblique drilling is machined;

[0093] S92, the drill bit 13 is inserted into the second plane 17 and drilled to obtain the second guide hole 18;

[0094] S93, inserting the carbide drill bit 14 into the second guide hole 18 and drilling obliquely to the target depth to obtain the second drill hole;

[0095] S94 , the second reamer 16 is inserted into the second drill hole and expanded to the target inner diameter to obtain the target deep inclined hole 20 .

[0096] S10, when the first deep hole 2 is processed, the work disk 1 is rotated and step 9 is repeated to process the next deep hole 2 until all deep holes 2 are processed.

[0097] Because the overall depth of the stepped deep hole is relatively large, the deep hole in this embodiment is machined in sections, both front and back. That is, the large-diameter hole on one side of the workpiece 3 is first machined. After the workpiece 3 is flipped and aligned, the small-diameter hole on the other side of the workpiece 3 is machined. This machining method, on the one hand, reduces the length of the deep hole machining tool, avoiding the problem of poor machining accuracy caused by excessive tool length during deep hole machining, while also ensuring the coaxiality of the two deep holes. On the other hand, machining the large-diameter hole first and then the small-diameter hole facilitates the flow of coolant, achieving sufficient cooling and chip removal for the workpiece 3. Furthermore, each deep straight hole is machined in three steps: drilling a guide hole, drilling the deep hole, and reaming the hole. While the inclined hole is machined in four steps: milling a plane for centering the inclined surface, drilling a guide hole, drilling the deep hole, and reaming the hole. This design improves the machining accuracy of the deep straight or deep inclined holes, ensuring the shape, position, and size requirements of the deep straight or deep inclined holes, and reducing the roughness of the stepped deep straight or deep inclined holes.

[0098] Example 1:

[0099] The center nozzle flange in the re-ignition unit is pre-processed. The center nozzle flange includes a frustum 31, a frustum 32 and a frustum 3 which are sequentially arranged and integrally connected from top to bottom. Twelve groups of stepped inclined holes penetrating the upper and lower surfaces of the workpiece 3 need to be processed on the center nozzle flange. Each group of stepped inclined holes includes a coaxial and communicating large-diameter hole (target inclined hole 11) and a small-diameter hole (target inclined hole 20). The diameter of the large-diameter hole is φ9.6±0.1 and the hole depth is 71.5mm. The diameter of the small-diameter hole is φ6.6±0.1 and the hole depth is 40mm. The roughness of the stepped inclined hole is 3.2. Figure 1 As shown. During experimental machining, it was found that the currently available cutting tools could not meet the required diameter and roughness of the stepped, deep, inclined hole. Therefore, a new machining method was required to meet the requirements of the product illustration. This embodiment utilizes a Siemens 840D CNC five-axis linkage machine tool with a DMG DMU125FD system to machine stepped, deep, inclined holes. The CNC five-axis linkage machine tool is equipped with a worktable 1 and a three-jaw chuck 2 for clamping the workpiece 3, as well as a ruby ​​machine tool probe for measuring the center of a circle. The specific machining process is as follows:

[0100] S1, using 3D modeling software, such as CAD / CAM software, to model and program the center nozzle flange, and import the compiled program into a CNC five-axis linkage machine tool;

[0101] S2, fix the three-jaw chuck 2 at the center of the work plate 1 of the CNC five-axis linkage machine tool, level the upper surface of the three-jaw chuck 2, and control the error within 0.02mm. The three-jaw chuck 2 clamps and fixes the frustum 31 of the center nozzle flange to fix the center nozzle flange on the work plate 1, re-measure the horizontality of the upper surface of the center nozzle flange, and control its error within 0.02mm to achieve leveling of the center nozzle flange;

[0102] S3, center nozzle flange alignment, specific steps are as follows:

[0103] S31: Draw an alignment center line on the upper plane of the center nozzle flange along the diameter direction, and rotate the work disk 1 until the alignment center line on the center nozzle flange is vertically aligned with the X-axis in the workpiece coordinate system. This completes the C-axis alignment.

[0104] S32, using a ruby ​​probe of a CNC five-axis linkage machine tool to measure four coordinate values ​​of the outer circumferential surface of the frustum 31 of the center nozzle flange, and determining the center of the workpiece 3 based on the four coordinate values, thereby determining the center of the workpiece coordinate system;

[0105] S33, using a ruby ​​probe of a CNC five-axis linkage machine tool to contact the upper plane of the frustum 31 of the center nozzle flange to determine the position of the contact point in the workpiece coordinate system, thereby determining the position of the upper plane of the center nozzle flange in the workpiece coordinate system;

[0106] S4. A large-diameter hole is machined on the flat side of the center nozzle flange using a deep-hole machining tool. The deep-hole machining tool includes a drill bit 4, a drill bit 5, a milling cutter 6, and a reamer 7. The target diameter of the large-diameter hole is 9.6 mm. The diameter d1 of the milling cutter 6 is 8 mm, the diameter d2 of the drill bit 4 is 9 mm, the diameter d3 of the drill bit 5 is 9 mm, and the diameter d4 of the reamer 7 is 9.6 mm. (Since there is no standard 9.6 mm reamer on the market, an end mill is modified to form a reamer with a flat bottom surface by cutting off the bottom tip of the end mill.) The specific machining process is as follows:

[0107] S41, aligning the milling cutter 6 with the position of the oblique hole to be machined on the upper plane of the center nozzle flange, and machining a plane 8 for centering the oblique drilling;

[0108] S42, the drill bit 4 is inserted into the plane and drilled to obtain a guide hole 9 with a depth of 5 mm;

[0109] S44, inserting the carbide drill bit 5 into the guide hole 9 and drilling obliquely to the target depth of 71.5 mm, while leaving a machining allowance of 0.3 mm, to obtain the drill hole 10;

[0110] S44, reamer 7 is inserted into drill hole 10 and expanded to a target inner diameter of 9.6 mm to obtain a large-diameter hole;

[0111] S5, when the first large-diameter hole is machined, the work disc 1 is rotated according to the angle between two adjacent large-diameter holes, and step 4 is repeated to machine the next large-diameter hole until all large-diameter holes are machined;

[0112] S6, two symmetrically arranged standard holes 12 are machined on the center plane of the center nozzle flange to serve as alignment holes after the workpiece 3 is flipped, to ensure that there is no deviation in the C-axis direction of the workpiece 3 before and after flipping;

[0113] S7, flip the three-jaw chuck 2 and fix it at the center of the work plate 1 of the CNC five-axis linkage machine tool, level the contact surface between the three-jaw chuck 2 and the center nozzle flange, and control the error within 0.02mm; flip the workpiece 3, and clamp and fix the frustum 2 32 of the center nozzle flange with the three-jaw chuck 2 to fix the center nozzle flange on the work plate 1 again, and re-measure the horizontality of the upper plane of the center nozzle flange before flipping, so that the error is controlled within 0.02mm;

[0114] S8, using the two alignment holes to align the workpiece 3, the specific process is as follows:

[0115] S81, using a ruby ​​probe of a CNC five-axis linkage machine tool, respectively measure at least three coordinate values ​​of the inner wall surfaces of the two alignment holes, and determine the center point of each alignment hole based on the at least three coordinate values. Determine an alignment center line based on the center points of the two alignment holes, and rotate the work disk 1 so that the alignment center line is aligned with the x-axis in the workpiece coordinate system in the vertical plane. At this time, there is no deviation in the C-axis direction of the workpiece 3 before and after flipping.

[0116] S82, measuring at least three coordinate values ​​of the outer surface of the central nozzle flange using a machine tool probe, and determining the center of the workpiece 3 based on the at least three coordinate values, thereby determining the center of the workpiece coordinate system;

[0117] S83, using the upper plane of the center nozzle flange before flipping as a machining reference, and determining the position of the machining surface of the center nozzle flange in the workpiece coordinate system; specifically, using a machine tool probe to contact the contact surface between the three-jaw chuck 2 and the upper plane of the center nozzle flange before flipping, to determine the position of the contact surface in the workpiece coordinate system, thereby determining the position of the machining surface of the center nozzle flange (the lower surface of the center nozzle flange) in the workpiece coordinate system; alternatively, determining the position of the machining surface of the center nozzle flange after flipping in the workpiece coordinate system based on the thickness of the center nozzle flange and the coordinate value of the upper plane of the center nozzle flange before flipping;

[0118] S9. Use a deep hole machining tool to machine a small-diameter hole in the center nozzle flange. The deep hole machining tool includes a third drill bit 13, a fourth drill bit 14, a second milling cutter 15, and a second reamer 16. The target diameter of the small-diameter hole is 6.6 mm. The diameter of the second milling cutter 15 is 5 mm, the diameter of the third drill bit 13 is 6 mm, the diameter of the fourth drill bit 14 is 6 mm, and the diameter of the second reamer 16 is 6.6 mm. The specific process is as follows:

[0119] S91, the second milling cutter 15 is aligned with the position of the oblique hole to be machined on the workpiece 3, and a second plane 17 for centering the oblique drilling is machined;

[0120] S92, the drill bit 13 is inserted into the second plane 17 and drilled to obtain a second guide hole 18 with a depth of 5 mm;

[0121] S93, inserting the carbide drill bit 14 into the second guide hole 18 and drilling obliquely to the target depth with a machining allowance of 0.1 mm to obtain the second drill hole;

[0122] S94, the second reamer 16 is inserted into the second drill hole and expanded to the target inner diameter to obtain a small diameter hole.

[0123] S10, when the first small-diameter hole is machined, the work disc 1 is rotated according to the angle between two adjacent small-diameter holes, step 9 is repeated, and the next small-diameter hole is machined until all small-diameter holes are machined.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention 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 invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for processing a stepped deep hole, characterized in that: The stepped deep hole of the workpiece includes at least two sequentially connected and coaxial deep holes. The machining of the stepped deep hole is achieved using a CNC five-axis linkage machine tool. The CNC five-axis linkage machine tool is equipped with a worktable for clamping the workpiece. The specific machining process is as follows: S1, use 3D modeling software to model and program the workpiece, and import the compiled program into the CNC five-axis linkage machine tool; S2, clamping the workpiece on the worktable and leveling it; S3, workpiece alignment; S4, using a deep hole machining tool to machine the first deep hole on the upper plane of the workpiece, and setting it as deep hole one; S5, when the first deep hole 1 is processed, the work disk is rotated and step 4 is repeated to process the next deep hole 1 until all deep holes 1 are processed; S6, machining two symmetrically arranged standard holes on the center plane of the workpiece to serve as alignment holes after the workpiece is turned over; S7, flip the workpiece, clamp the workpiece on the workpiece plate again and level it; S8, align the workpiece using two aligning holes; S9, using a deep hole processing tool to process the first deep hole of the flip surface, and setting it as deep hole 2; S10, when the first deep hole 2 is processed, the work disk is rotated and step 9 is repeated to process the next deep hole 2 until all deep holes 2 are processed.

2. A method for processing a stepped deep hole according to claim 1, characterized in that: The CNC five-axis linkage machine tool further includes a machine tool probe, and the S3 includes the following steps: S31, draw the alignment center line along the diameter direction on the upper plane of the workpiece, and rotate the work disk until the alignment center line on the workpiece is aligned with the x-axis of the workpiece coordinate system on the vertical plane. At this time, the C-axis alignment is completed; S32, measuring at least three coordinate values ​​of the outer cylindrical surface of the workpiece using a machine tool probe, and determining the center of the workpiece based on the at least three coordinate values; S33, using the machine tool probe to contact the upper plane of the workpiece, determine the position of the contact point in the workpiece coordinate system, and thus determine the position of the upper plane of the workpiece in the workpiece coordinate system.

3. The method for machining a stepped deep hole according to claim 1, characterized in that: In the above-mentioned S4, when the deep hole 1 is a straight hole, the deep hole processing tools include drill bit 1, drill bit 2 and reamer 1. Assuming that the target hole diameter of the deep hole 1 is d, the diameter of the drill bit 1 is d2, the diameter of the drill bit 2 is d3, and the diameter of the reamer 1 is d4, wherein d2=d3<d4=d; S4 includes the following steps: S41, aligning the drill bit 1 with the upper plane of the workpiece to be processed and drilling to obtain a guide hole 1; S42, the drill bit 2 is inserted into the guide hole 1 and drills to a target depth to obtain the drill hole 1; S43, reamer one is inserted into drill hole one and the hole is expanded to a target inner diameter to obtain a target deep hole one.

4. The method for machining a stepped deep hole according to claim 1, wherein: In the above S4, when the deep hole 1 is a deep inclined hole, the deep hole processing tools include a drill bit 1, a drill bit 2, a milling cutter 1, and a reamer 1. Assuming that the target hole diameter of the deep inclined hole 1 is d, the diameter of the milling cutter 1 is d1, the diameter of the drill bit 1 is d2, the diameter of the drill bit 2 is d3, and the diameter of the reamer 1 is d4, wherein d1 < d2 = d3 < d4 = d; S4 includes the following steps: S41, the milling cutter 1 is aligned with the position of the inclined hole to be machined on the workpiece, and a plane 1 for centering the inclined drilling is machined; S42, the drill bit 1 is inserted into the plane 1 and drills a hole to obtain the guide hole 1; S43, the drill bit 2 is inserted into the guide hole 1 and drilled obliquely to the target depth to obtain the drill hole 1; S44, reamer one is inserted into drill hole one and the hole is expanded to a target inner diameter to obtain a target deep inclined hole one.

5. The method for machining a stepped deep hole according to claim 1, wherein: When the deep hole is divided into three sections, after deep hole one is processed, the deep hole processing tool is sequentially inserted into deep hole one and processes the middle section deep holes until all the middle section deep holes are processed.

6. A method for machining a stepped deep hole according to claim 1, characterized in that: The S8 comprises the following steps: S81, using a machine tool probe to measure at least three coordinate values ​​of the inner wall surfaces of the two alignment holes, and determining the center point of each alignment hole based on the at least three coordinate values, determining an alignment center line based on the center points of the two alignment holes, and rotating the worktable so that the alignment center line is aligned with the x-axis in the workpiece coordinate system in the vertical plane, and at this time, there is no deviation in the C-axis direction before and after the workpiece is flipped; S82, measuring at least three coordinate values ​​of the outer cylindrical surface of the workpiece using a machine tool probe, and determining the center of the workpiece based on the at least three coordinate values, thereby determining the center of the workpiece coordinate system; S83, taking the upper plane of the workpiece before flipping as a machining reference, and determining the position of the machining surface of the workpiece in the workpiece coordinate system.

7. A method for machining a stepped deep hole according to claim 6, characterized in that: In the above S7, a three-jaw chuck is used to clamp and fix the workpiece. In the above S83, a machine tool probe is used to contact the contact surface between the three-jaw chuck and the upper plane of the workpiece before flipping, and the position of the contact surface in the workpiece coordinate system is determined, thereby determining the position of the machining surface of the workpiece in the workpiece coordinate system.

8. The method for machining a stepped deep hole according to claim 6, wherein: In the above-mentioned S83, the position of the machining surface after the workpiece is flipped in the workpiece coordinate system is determined based on the thickness of the workpiece and the coordinate values ​​of the upper plane of the workpiece before flipping.

9. The method for machining a stepped deep hole according to claim 1, characterized in that: In S9, when the deep hole is a straight hole, the deep hole processing tools include drill bit 3, drill bit 4, and reamer 2. Assume that the target hole diameter of deep hole 2 is d′, the diameter of drill bit 3 is d′2, the diameter of drill bit 4 is d′3, and the diameter of reamer 2 is d′4, where d′2=d′3<d′4=d′; S9 includes the following steps: S91, drill bit 3 is aligned with the flip surface of the workpiece to be processed and drills a hole to obtain a second guide hole; S92, the drill bit 4 is inserted into the guide hole 2 and drilled to the target depth to obtain the drill hole 2; S93, the second reamer is inserted into the second drill hole and expanded to the target inner diameter to obtain the second target deep hole.

10. The method for machining a stepped deep hole according to claim 1, characterized in that: In the above-mentioned S9, when the deep hole is a deep inclined hole, the deep hole processing tools include drill bit 3, drill bit 4, milling cutter 2 and reamer 2, assuming that the target hole diameter of the deep inclined hole 2 is d', the diameter of the milling cutter 2 is d'1, the diameter of the drill bit 3 is d'2, the diameter of the drill bit 4 is d'3, and the diameter of the reamer 2 is d'4, wherein d'1 < d'2 = d'3 < d'4 = d'; S9 includes the following steps: S91, the second milling cutter is aligned with the position of the oblique hole to be machined on the workpiece, and a second plane for centering the oblique drilling is machined; S92, the drill bit 3 is inserted into the plane 2 and drilled to obtain the pilot hole 2; S93, the drill bit 4 is inserted into the guide hole 2 and drilled obliquely to the target depth to obtain the drill hole 2; S94, the second reamer is inserted into the second drill hole and expanded to the target inner diameter to obtain the target deep inclined hole second.

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