Numerical control machining method for magnetically soft alloy thin-wall rotary workpiece with large length-diameter ratio
By using specialized mandrels, positioning fixtures, and front guide devices in aerospace machining, combined with CNC technology, the deformation and efficiency problems of thin-walled rotary parts with large length-to-diameter ratios have been solved, achieving high-precision and high-efficiency machining results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-27
- Publication Date
- 2026-03-31
AI Technical Summary
In aerospace machining, thin-walled rotating parts with large length-to-diameter ratios are prone to deformation and have low machining efficiency under traditional machining methods, resulting in poor dimensional uniformity and precision control, making it difficult to meet the needs of mass production and assembly.
By employing specialized mandrels, positioning fixtures, and front guide devices, combined with CNC machining technology, and through precise positioning, clamping, and deformation control, efficient workpiece machining is achieved.
It improves the machining quality and consistency of thin-walled rotary parts with large length-to-diameter ratio, ensures high precision and surface finish, meets assembly requirements, reduces rework and repair, and improves machining efficiency.
Smart Images
Figure CN121756020A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aerospace mechanical processing technology, specifically relating to a CNC machining method suitable for thin-walled rotary workpieces with large aspect ratio of soft magnetic alloys. Background Technology
[0002] The aerospace mechanical manufacturing field contains a large number of rotating structural components. Among them, thin-walled parts are characterized by their thin walls and poor control over wall thickness uniformity and consistency during processing. However, in the actual assembly process, the wall thickness of these parts is a critical characteristic factor, requiring high precision control. Traditional processing methods, using manual lathes for clamping and machining, make it difficult to control deformation during processing. Furthermore, the cumulative error of the positioning fixture often leads to rework, repair, or reshaping after machining, resulting in poor dimensional uniformity and precision control, low first-pass yield, and low processing efficiency, which cannot meet the needs of normal batch production and assembly. Summary of the Invention
[0003] This invention addresses the problems of easy deformation and low processing efficiency in machining thin-walled rotary parts with large aspect ratios, and provides a CNC machining method for soft magnetic alloy thin-walled rotary workpieces with large aspect ratios that has high processing efficiency and stable and reliable processing quality.
[0004] The technical solution of this invention is implemented as follows: A CNC machining method for thin-walled rotary workpieces with a large aspect ratio of soft magnetic alloy includes the following steps: Set up the first positioning fixture, the second positioning fixture, the mandrel, and the front guide device used in the machining process; Insert the mandrel into the inner hole of the workpiece; The workpiece is guided into the spring collet by the front guide device, and then mounted on the lathe using the lathe spring collet. Fixed calipers are used to ensure that the workpiece protrusion length is consistent, and the tailstock center supports the mandrel. Clamp the outer circle of the workpiece and perform rough and finish machining on one end of the outer circle of the workpiece respectively; Turn around, use the first positioning fixture to fix the clamping position, clamp the outer circle of the workpiece, and perform rough and fine machining on the other end of the outer circle of the workpiece respectively; Clamp the outer circle of the workpiece, fix the calipers to ensure that the workpiece protrusion length is consistent, precision turn the end face, bore the inner hole, and clean the root of the inner hole; Turn the workpiece around, use the second positioning fixture to fix the extension length, clamp the outer circle of the workpiece, flatten the end face, ensure the total length of the workpiece, and machine and adjust the threaded hole. After completing the above processing steps, inspect the threaded hole of the workpiece and check the outer diameter of one end of the thread. Then, perform secondary repair of the thread and precision machining of the outer diameter until the thread and outer diameter meet the design requirements.
[0005] As a further aspect of the present invention: the workpiece to be processed has the following characteristics: The workpiece has a linear structure on its rotating surface, a length exceeding 200mm, a wall thickness less than or equal to 0.5mm, an inner cavity that is a through hole, and a tight tolerance smooth hole and a threaded hole at both ends, with the diameter difference between the tight tolerance smooth hole and the middle inner cavity hole not exceeding 0.3mm.
[0006] As a further aspect of the present invention: the clamping length of the mandrel satisfies the following condition: the clamping length exceeds two-thirds of the inner hole length of the workpiece; The diameter of the outer circle of the mandrel must be compatible with the inner hole of the workpiece, and it can be inserted into the workpiece from both ends. The large end face of the mandrel has a center hole, and the center hole and the clamping outer circle are required to be coaxial. The small end of the mandrel has a large chamfer; The average clearance between the outer circle of the mandrel and the inner hole of the workpiece is 0.006mm-0.01mm.
[0007] As a further aspect of the present invention: the front guide device includes: a front guide positioning base, a front guide fixing base, and a front guide positioning block; The front guide positioning base is a cylindrical structure with two stepped through holes in the middle for fixing to the lathe adapter; The front guide fixing base is a cylindrical structure with a through hole in the middle. There are three threaded locking holes on one end face for fixing the front guide positioning block. The front guide positioning block has a stepped hole in the middle. The large hole is to avoid interference from the lathe spring collet, and the small hole in the middle is for guiding purposes. The front guide positioning base is fixed to the machine tool adapter by screws passing through three deep holes on the end face. The front guide fixing base is connected by the threaded holes on the three end faces, and the end face of the front guide fixing base is pressed against the end face of the front guide positioning base. The front guide positioning block is passed through the inner hole of the front guide fixing base, and the front guide positioning block is fixed in place by screws in the oblique threaded holes on the end face.
[0008] As a further aspect of the present invention: the inner hole of the front guide fixing base and the outer circle of the front guide positioning block are in clearance fit, with the fit clearance between 0.012mm and 0.05mm.
[0009] As a further aspect of the present invention: the first positioning fixture is used to fix the clamping position after the first precision turning of the outer diameter and the second precision turning of the outer diameter; The first positioning fixture has a semi-circular arc structure with a stepped circle; the diameter difference between the outer circle of the large step and the outer circle of the small step is 3mm-5mm. The inner hole of the first positioning fixture is adapted to the diameter of the workpiece after precision machining, and both end faces are required to be perpendicular to the inner hole.
[0010] As a further embodiment of the present invention: the second positioning fixture includes: a transition joint, a positioning seat, a main positioning rod, a rear positioning support seat, a transition positioning rod, and a rear positioning seat; The transition joint has a central inner hole and a threaded structure, used to fix it on the lathe cylinder and connect to the positioning seat; The positioning seat has a cylindrical structure with an inner hole in the middle for connecting the transition joint; The main positioning rod is a slender shaft structure with a central inner hole, serving as a guide, positioning, and support mechanism, and is used to connect to the transition positioning rod. The rear positioning support is a ring-groove cylindrical structure with a central inner hole for fixing and supporting the main positioning rod; The transition positioning rod is a slender shaft structure with an inner hole in the middle, used to connect to the rear positioning seat; The rear positioning seat is a cylindrical structure with an annular groove and an inner hole in the middle, used for rear positioning of the workpiece.
[0011] As a further embodiment of the present invention: a sealing groove is adopted at the root of the internal thread at one end of the transition joint for connecting the main positioning rod and the sealing ring; The outer circumference of one end of the transition joint is fitted with a threaded dead hole to connect the main positioning rod and prevent loosening.
[0012] As a further aspect of the present invention: the middle part of the main positioning rod adopts an annular groove structure, and the gap between the outer circle of the annular groove and the rear positioning support is 0.01mm-0.05mm; The rear positioning support adopts a sealing ring groove structure, and the outer diameter of the ring groove is 0.5mm smaller than the inner diameter of the machine tool spindle.
[0013] As a further aspect of the present invention: all components included in the second positioning fixture are hollow in structure, for cooling and chip removal at the center of the machine tool. The second positioning fixture uses a main positioning rod and a transition positioning rod. The main positioning rod is fixed to the machine tool cylinder, and its axial position will not change with the rotation of the spindle.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention solves the problems of easy deformation and low processing efficiency in machining thin-walled rotary parts with large length-to-diameter ratio. The key to the machining is that it is necessary to customize the mandrel and positioning fixture according to the inner hole diameter and length to ensure the final size and accuracy requirements.
[0015] 2. This invention solves the problem of difficult machining and control of wall thickness dimensions for easily deformable thin-walled parts with large aspect ratios made of soft magnetic alloys.
[0016] 3. The parts processed by this invention have good consistency, good surface finish, and very high product precision.
[0017] 4. The present invention achieves precise positioning, clamping and deformation control through specially designed mandrel, front guide device, first positioning fixture, second positioning fixture and other fixtures.
[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a workpiece according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a front guide device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a first positioning fixture according to an embodiment of the present invention; Figure 4 This is a schematic diagram of a second positioning fixture according to an embodiment of the present invention. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below with reference to the accompanying drawings.
[0021] In the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention.
[0022] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0023] The following is in conjunction with the appendix Figure 1-4 The embodiments of the present invention will be described in detail below.
[0024] Example 1 refer to Figures 1-3 The workpiece has a linear structure on its rotating surface, the part length exceeds 150mm, the wall thickness is less than or equal to 0.5mm, the inner cavity is a through hole, and there is a strict tolerance smooth hole and a threaded hole at both ends, and the difference between the strict tolerance smooth hole and the diameter of the middle inner cavity hole does not exceed 0.3mm.
[0025] The machining method for this soft magnetic alloy thin-walled rotary workpiece with a large aspect ratio may include the following steps: S1, set the first positioning fixture, mandrel, and front guide device used in the machining process; S2, pass the mandrel into the inner hole of the workpiece; S3, guide the workpiece into the spring collet through the front guide device, install the lathe spring collet on the lathe, use a fixed caliper to ensure that the workpiece protrusion length is consistent, use a dial indicator to align the workpiece, and use the tailstock center to support the mandrel. S4, clamp the outer circle of the workpiece, and perform rough and finish machining on one end of the outer circle of the workpiece respectively; S5, turn around, pass the mandrel into the inner hole of the workpiece, use calipers to fix the clamping position, use a dial indicator to align the workpiece, clamp the outer circle of the workpiece, use the tailstock center to support the mandrel, and perform rough and fine machining on the other end of the workpiece. S6, clamp the outer circle of the workpiece, fix the caliper to ensure that the extension length of the workpiece is consistent, finish turn the end face, bore the inner hole, and clean the root of the inner hole; S7, turn around, use the first positioning fixture to fix the extension length, clamp the outer circle of the workpiece, flatten the end face, ensure the total length of the workpiece, and machine and adjust the threaded hole; S8, clamp the outer diameter, and use a suitable external turning tool to finish the outer diameter. S9, turn around, clamp the outer diameter, and use a suitable external turning tool to finish the outer diameter. S10. After completing the above steps, inspect the threaded hole of the workpiece and check the outer diameter of one end of the thread. If it is not up to standard, repair the thread a second time and finish turn the outer diameter until the thread and outer diameter meet the design requirements.
[0026] In some embodiments, the clamping length of the mandrel satisfies the following requirements: the clamping length exceeds two-thirds of the inner diameter of the workpiece; the diameter of the outer circle of the mandrel is required to match the inner diameter of the workpiece; and the workpiece can be fed in from both ends. The large end face of the mandrel has a center hole, and the center hole and the clamping outer circle are required to be coaxial; the small end of the mandrel has a large chamfer.
[0027] In some embodiments, the front guide device includes: a front guide positioning base 11, a front guide fixing base 12, and a front guide positioning block 13.
[0028] The inner hole of the front guide fixing base 12 and the outer circle of the front guide positioning block 13 are in clearance fit, with the fit clearance between 0.012mm and 0.05mm.
[0029] The second positioning fixture includes: a transition joint 41, a positioning seat 42, a main positioning rod 43, a rear positioning support seat 44, a transition positioning rod 45, and a rear positioning seat 46.
[0030] Example 2 This invention provides a method for machining thin-walled, rotating parts of soft magnetic alloys with a large aspect ratio on CNC lathes. By fixing the part's position on the lathe, the outer diameters at both ends are machined first, and secondary positioning is used to ensure a small tool contact on the outer diameters. Then, a dedicated positioning fixture is used to machine the inner hole, overall length, and threads. This method solves the problems of easy deformation and low machining efficiency in thin-walled, rotating parts with a large aspect ratio. The key to this method is the need to customize mandrels and positioning fixtures to the appropriate specifications based on the inner hole diameter and length to ensure the final dimensions and accuracy requirements. This invention also solves the problem of difficult machining and control of the wall thickness of easily deformable thin-walled, soft magnetic alloy parts with a large aspect ratio. This method includes the following steps: Step 1: Insert the mandrel into the inner hole of the workpiece, clamp the workpiece blank, and load the workpiece into the lathe spring collet using the front guide device. Step 2: Clamp the outer circle of the workpiece, use a fixed caliper to ensure that the extension length of the workpiece is consistent, use a dial indicator to align the outer circle of the workpiece, and use the tailstock center to support the mandrel. Step 3: Select a suitable external turning tool to rough machine the outer circle; Step 4: Select a suitable external turning tool to perform finishing on the outer circle; Step 5: Turn the workpiece around, use calipers to fix the clamping position, use a dial indicator to align the outer circle of the workpiece, and use the tailstock center to support the mandrel. Step 6: Select a suitable external turning tool to rough machine the outer circle; Step 7: Select a suitable external turning tool to perform finishing on the outer circle; When inserting the mandrel into the inner hole, the length of the mandrel needs to exceed two-thirds of the length of the inner hole of the workpiece, and the workpiece and the root of the mandrel step should be completely in contact. When clamping, the clamping air pressure of the lathe should be adjusted to the lowest possible value. The clamping force of the lathe tailstock center should be adjusted to the minimum possible value. After this is completed, machining can begin. Step 8: Clamp the outer circle of the workpiece, fix the calipers to ensure that the workpiece protrusion length is consistent, finish turn the end face, bore the inner hole, and clean the root of the inner hole; Step 9: Turn around, use the first positioning fixture to fix the extended length, clamp the outer circle of the workpiece, flatten the end face, ensure the total length of the workpiece, and machine and adjust the threaded hole; Step 10: Clamp the outer circle and use a suitable external turning tool to finish the outer circle. Step 11: Turn the machine around, clamp the outer diameter, and use a suitable external turning tool to finish the outer diameter. Step 12: After completing the above steps, inspect the threaded hole of the workpiece and check the outer diameter of one end of the thread. If it does not meet the requirements, clamp the outer diameter and perform secondary repair of the thread and the outer diameter by precision machining until the thread and outer diameter meet the design requirements.
[0031] In some embodiments, a method for machining a soft magnetic alloy thin-walled rotary part with a large aspect ratio includes the following steps: Step 1: Insert the mandrel into the inner hole of the workpiece, clamp the workpiece blank (specification: G13.2×0.5×380), and use the front guide device to load the workpiece into the lathe spring collet; Step 2: Clamp the outer diameter of the workpiece, use a fixed caliper to ensure that the workpiece extends 230mm (including the front end of the mandrel), use a dial indicator to caliper the outer diameter of the workpiece to ensure that the runout is within 0.05mm, and use the tailstock center to support the mandrel. Step 3: Rough turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to rough turn the outer diameter to φ13mm. The spindle speed is 600~800r / min and the feed rate is 0.1mm / r. Step 4: Finish turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to finish turn the outer diameter to φ12.94mm. The spindle speed is 600~800r / min and the feed rate is 0.03mm / r. Step 5: Turn the workpiece around and fix it at the junction of the outer circles after the first machining using the first positioning fixture 31. Use a dial indicator to align the outer circle of the workpiece within 0.05mm and use the tailstock center to support the mandrel. Step 6: Rough turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to rough turn the outer diameter to φ13mm. The spindle speed is 600~800r / min and the feed rate is 0.1mm / r. Step 7: Finish turn the outer diameter. Use a carbide turning tool (tool grade selection: KC730, KCU10B) to finish turn the outer diameter to φ12.94mm. The spindle speed is 600~800r / min and the feed rate is 0.03mm / r. When inserting the mandrel into the inner hole, the length of the mandrel needs to exceed two-thirds of the length of the inner hole of the workpiece, and the workpiece and the root of the mandrel step should be completely in contact. When clamping, the clamping air pressure of the lathe should be adjusted to the lowest possible value. The clamping force of the lathe tailstock center should be adjusted to the minimum possible value. After this is completed, machining can begin. Step 8: Clamp the outer diameter of the workpiece, fix the calipers to ensure the workpiece extends 15mm, and use a carbide tool to finish turn the end face, removing 0.5mm of allowance. Tool selection: KC730, KCU10B, spindle speed: 600r / min, feed rate: 0.03mm / r. Use a carbide tool to bore the inner hole and clean the root of the inner hole. Tool selection: PICCO R010.1508-10IC228, spindle speed: 600r / min, rough boring, feed rate: 0.05~0.1mm / r, finish boring, 0.025~0.03mm / r. Step 9: Turn the workpiece around, use the second positioning fixture to fix the extended length of 30mm, clamp the outer circle of the workpiece, cut the end face, ensure the total length of the workpiece, bore the threaded bottom hole, tool type: PICCO R010.1508-10IC228, spindle speed: 600r / min, feed rate: 0.05mm / r; thread picking, use a carbide turning tool (tool type: PICCO R004.0105-10IC908), spindle speed: 600r / min, feed rate: 0.02mm / r; Step 10: After completing the above steps, inspect the threaded hole of the workpiece and check the outer diameter of one end of the thread. If it is not up to standard, clamp the outer diameter, extend it 15mm beyond the part, and pick the thread. Use a carbide turning tool (tool grade: PICCOR004.0105-10IC908), spindle speed 600r / min, feed rate 0.02mm / r; finish turn the outer diameter using a carbide turning tool (tool grade: KC730, KCU10B) to φ12.94mm, spindle speed 600~800r / min, feed rate 0.03mm / r; until the thread and outer diameter dimensions meet the design requirements.
[0032] Example 3 This invention provides a method for machining thin-walled rotary workpieces with a large aspect ratio made of soft magnetic alloy, comprising the following steps: Set up the first positioning fixture, mandrel, and front guide device used in the machining process; Insert the mandrel into the inner hole of the workpiece; The workpiece is guided into the spring collet by the front guide device, and then mounted on the lathe using the lathe spring collet. Fixed calipers are used to ensure that the workpiece protrusion length is consistent, and the tailstock center supports the mandrel. Clamp the outer circle of the workpiece and perform rough and finish machining on one end of the outer circle of the workpiece respectively; Turn the workpiece around, use calipers to fix the clamping position, clamp the outer circle of the workpiece, and perform rough and fine machining on the other end of the outer circle of the workpiece. Clamp the outer circle of the workpiece, fix the calipers to ensure that the workpiece protrusion length is consistent, precision turn the end face, bore the inner hole, and clean the root of the inner hole; Turn around, use the first positioning fixture to fix the extension length, clamp the outer circle of the workpiece, flatten the end face, ensure the total length of the workpiece, and machine and adjust the threaded hole; Clamp the outer diameter and finish turn the outer diameter; Turn around, clamp the outer diameter, and finish turn the outer diameter; After completing the above processing steps, inspect the threaded hole of the workpiece and check the outer diameter of one end of the thread. If it is not up to standard, repair the thread a second time and finish turn the outer diameter until the thread and outer diameter meet the design requirements.
[0033] In another embodiment, the steps are as follows: Step 1: Insert the mandrel into the inner hole of the workpiece, clamp the workpiece blank (specification: G10×0.65×200), and use the front guide device to load the workpiece into the lathe spring collet. Step 2: Clamp the outer diameter of the workpiece, use a fixed caliper to ensure that the workpiece extends 130mm (including the front end of the mandrel), use a dial indicator to caliper the outer diameter of the workpiece to ensure that the runout is within 0.05mm, and use the tailstock center to support the mandrel. Step 3: Rough turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to rough turn the outer diameter to φ9.8mm. The spindle speed is 600~800r / min and the feed rate is 0.1mm / r. Step 4: Finish turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to finish turn the outer diameter to φ9.6mm. The spindle speed is 600~800r / min and the feed rate is 0.03mm / r. Step 5: Turn the workpiece around and fix it at the junction of the outer circles after the first machining using the first positioning fixture 31. Use a dial indicator to align the outer circle of the workpiece within 0.05mm and use the tailstock center to support the mandrel. Step 6: Rough turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to rough turn the outer diameter to φ9.8mm. The spindle speed is 600~800r / min and the feed rate is 0.1mm / r. Step 7: Finish turn the outer diameter. Use a carbide turning tool (tool type: KC730, KCU10B) to finish turn the outer diameter to φ9.6mm. The spindle speed is 600~800r / min and the feed rate is 0.03mm / r. When inserting the mandrel into the inner hole, the length of the mandrel needs to exceed two-thirds of the length of the inner hole of the workpiece, and the workpiece and the root of the mandrel step should be completely in contact. When clamping, the clamping air pressure of the lathe should be adjusted to the lowest possible value. The clamping force of the lathe tailstock center should be adjusted to the minimum possible value. After this is completed, machining can begin. Step 8: Clamp the outer diameter of the workpiece, fix the calipers to ensure the workpiece extends 15mm, and use a carbide tool to finish turn the end face, removing 0.5mm of allowance. Tool selection: KC730, KCU10B, spindle speed: 600r / min, feed rate: 0.03mm / r. Use a carbide tool to bore the inner hole and clean the root of the inner hole. Tool selection: PICCO R010.1508-10IC228, spindle speed: 600r / min, rough boring, feed rate: 0.05~0.1mm / r, finish boring, 0.025~0.03mm / r. Step 9: Turn the workpiece around, use the second positioning fixture to fix the extended length of 30mm, clamp the outer circle of the workpiece, cut the end face, ensure the total length of the workpiece, bore the threaded bottom hole, tool type: PICCO R010.1508-10IC228, spindle speed: 600r / min, feed rate: 0.05mm / r; thread picking, use a carbide turning tool (tool type: PICCO R004.0105-10IC908), spindle speed: 600r / min, feed rate: 0.02mm / r; Step 10: Clamp the outer diameter, extending 15mm beyond the part. Use a carbide turning tool (tool type: KC730, KCU10B) to finish turn the outer diameter to φ9.5mm. The spindle speed is 600~800r / min, and the feed rate is 0.03mm / r. Step 11: Turn the machine around, clamp the outer diameter, extend the length of the part by 15mm, and use a carbide turning tool (tool grade selection: KC730, KCU10B) to finish turn the outer diameter to φ9.5mm. The spindle speed is 600~800r / min and the feed rate is 0.03mm / r. Step 12: After completing the above steps, inspect the threaded hole of the workpiece and check the outer diameter of one end of the thread. If it is not up to standard, clamp the outer diameter, extend it 15mm beyond the part, and pick the thread. Use a carbide turning tool (tool grade: PICCOR004.0105-10IC908), spindle speed 600r / min, feed rate 0.02mm / r; finish turn the outer diameter using a carbide turning tool (tool grade: KC730, KCU10B) to φ9.5mm, spindle speed 600~800r / min, feed rate 0.03mm / r; until the thread and outer diameter dimensions meet the design requirements.
[0034] This invention solves the problems of easy deformation and low processing efficiency in machining thin-walled rotary parts with large aspect ratios. The key to this process lies in customizing mandrels and positioning fixtures to the appropriate specifications based on the inner hole diameter and length to ensure the final dimensions and accuracy requirements. This invention also solves the problem of difficult machining and control of the wall thickness of easily deformable thin-walled soft magnetic alloy parts with large aspect ratios. Parts processed by the method described in this invention exhibit good consistency, surface finish, and very high product precision. The beneficial effects of this invention include the above-mentioned aspects. Furthermore, for such magnetic performance parts, this method can control the magnetic performance indicators, such as coercivity, to a certain extent, which is beneficial for the assembly and testing of downstream components. Moreover, this method enables rapid part positioning, reducing the need for repeated measurement and positioning during machining compared to traditional methods.
[0035] Thus, the objective of this invention has been achieved.
[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A numerical control machining method for a soft magnetic alloy large-length-diameter-ratio thin-wall rotary workpiece, characterized by, The method comprises the following steps: setting a first positioning tool, a second positioning tool, a mandrel, and a front guide device used in the machining process; inserting the mandrel into the inner hole of the workpiece; guiding the workpiece into the inside of the spring chuck through the front guide device, installing the spring chuck on the lathe, ensuring the consistent length of the workpiece by using the fixed caliper, and supporting the mandrel with the tailstock center; clamping the outer circle of the workpiece, and performing rough and fine machining on the outer circle of one end of the workpiece, respectively; turning over, clamping the outer circle of the workpiece by using the first positioning tool to fix the clamping position, and performing rough and fine machining on the outer circle of the other end of the workpiece, respectively; clamping the outer circle of the workpiece, ensuring the consistent length of the workpiece by using the fixed caliper, finishing the end face, boring the inner hole, and cleaning the root of the inner hole; turning over, fixing the length of the workpiece by using the second positioning tool, clamping the outer circle of the workpiece, finishing the end face, ensuring the total length of the workpiece, and machining and adjusting the threaded hole; after the above steps are completed, detecting the threaded hole of the workpiece and checking the size of the outer circle of the threaded end, and performing secondary repair on the thread and fine machining on the outer circle until the size of the thread and the outer circle meets the design requirements.
2. The soft magnetic alloy large-aspect-ratio thin-walled rotational workpiece NC machining method according to claim 1, characterized by, The features of the workpiece to be machined are as follows: the rotary surface of the workpiece is in a straight line structure, the length of the part exceeds 200 mm, the wall thickness is less than or equal to 0.5 mm, the inner cavity is a through hole, there is a tight tolerance light hole and a threaded hole at both ends, and the diameter difference between the tight tolerance light hole and the middle inner cavity hole is not more than 0.3 mm.
3. The soft magnetic alloy large-aspect-ratio thin-walled rotational workpiece NC machining method according to claim 1, characterized by, The clamping length of the mandrel (21) satisfies that the clamping length exceeds two-thirds of the length of the inner hole of the workpiece; the diameter requirement of the mandrel (21) matched with the outer circle is adapted to the inner hole of the workpiece, and the mandrel can be inserted into the workpiece from both ends; the large end face of the mandrel (21) has a center hole, and the center hole and the clamped outer circle have coaxiality requirements; the small end of the mandrel (21) has a large chamfer; the average clearance between the outer circle of the mandrel (21) and the inner hole of the workpiece is 0.006 mm-0.01 mm.
4. The soft magnetic alloy large-aspect-ratio thin-walled rotational workpiece NC machining method according to claim 1, characterized by, The front guide device comprises a front guide positioning base (11), a front guide fixed base (12), and a front guide positioning block (13). The front guide positioning base (11) is in a cylindrical structure, has two stepped through holes in the middle for fixing on the lathe adapter; the front guide fixed base (12) is in a cylindrical structure, has a through hole in the middle, and has three threaded locking holes in one end face for fixing the front guide positioning block; the front guide positioning block (13) has a stepped hole in the middle, a large hole for avoiding interference with the lathe spring chuck, and a small hole in the middle for guiding; the front guide positioning base (11) is fixed on the lathe adapter by screws passing through the three deep holes in the end face, the front guide fixed base (12) is connected by using the three threaded holes in the end face, and the end face of the front guide fixed base (12) is pressed against the end face of the front guide positioning base (11), the front guide positioning block (13) is inserted into the inner hole of the front guide fixed base (12), and the front guide positioning block (13) is fixed by using the inclined threaded holes in the end face.
5. The soft magnetic alloy large-aspect-ratio thin-walled rotational workpiece NC machining method according to claim 4, characterized by, The inner hole of the front guide fixed base (12) and the outer circle of the front guide positioning block (13) are in clearance fit, and the fit clearance is between 0.012 mm and 0.05 mm.
6. The soft magnetic alloy large-aspect-ratio thin-walled rotational workpiece NC machining method according to claim 1, characterized by, The first positioning tool (31) is used to fix the clamping position when the outer circle is machined for the second time after the outer circle is machined for the first time. The first positioning tool (31) is a semicircular structure with a step circle; the diameter difference between the large end step outer circle and the small step outer circle is 3mm-5mm; The inner hole of the first positioning tool (31) is matched with the diameter of the workpiece after finish turning, and the two end faces have perpendicularity requirements with the inner hole.
7. The soft magnetic alloy large-aspect-ratio thin-wall rotational workpiece NC machining method according to claim 1, characterized by, The second positioning tool includes: a transition joint (41), a positioning seat (42), a main positioning rod (43), a rear positioning support seat (44), a transition positioning rod (45), and a rear positioning seat (46); The transition joint (41) has an intermediate inner hole and a threaded structure, which is used to be fixed on the lathe oil cylinder and connected with the positioning seat (42); The positioning seat (42) is a cylindrical structure with an intermediate inner hole, which is used to connect the transition joint (41); The main positioning rod (43) is an elongated shaft structure with an intermediate inner hole, which is used for guiding positioning and supporting and connecting the transition positioning rod (45); The rear positioning support seat (44) is a ring groove cylindrical structure with an intermediate inner hole, which is used to fix and support the main positioning rod (43); The transition positioning rod (45) is an elongated shaft structure with an intermediate inner hole, which is used to connect the rear positioning seat (46); The rear positioning seat (46) is a ring groove cylindrical structure with an intermediate inner hole, which is used for workpiece positioning.
8. The soft magnetic alloy large-aspect-ratio thin-wall rotational workpiece NC machining method according to claim 7, characterized by, The inner thread root of one end of the transition joint (41) adopts a sealing groove, which is used to connect the main positioning rod (43) and the sealing ring; The outer circle of one end of the transition joint (41) adopts a threaded dead hole, which is connected with the main positioning rod (43) to prevent loosening.
9. The soft magnetic alloy large-aspect-ratio thin-wall rotational workpiece NC machining method according to claim 7, characterized by, The intermediate part of the main positioning rod (43) adopts a ring groove structure, and the gap between the ring groove outer circle and the rear positioning support seat (44) is 0.01mm-0.05mm; The rear positioning support seat (44) adopts a sealing ring groove structure, and the outer circle diameter of the ring groove is smaller than the inner hole diameter of the main shaft of the machine tool by 0.5mm.
10. The soft magnetic alloy large-aspect-ratio thin-walled rotational workpiece NC machining method according to claim 7, characterized by, All components included in the second positioning tool are hollow structures, which are used for machine tool center water cooling and chip removal; The second positioning tool adopts the main positioning rod (43) and the transition positioning rod (45) mode, and the main positioning rod (43) is fixed on the machine tool oil cylinder, and the axial position will not change with the rotation of the main shaft.