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CN-121988983-A - High-precision machining process and machining clamp for titanium alloy thin-wall frame assembly

CN121988983ACN 121988983 ACN121988983 ACN 121988983ACN-121988983-A

Abstract

The invention discloses a high-precision machining process and a machining fixture for a titanium alloy thin-wall frame assembly, which adopt six-stage progressive allowance cutting, heat treatment is coupled with machining depth, self-adaptive stress homogenization clamping is carried out through a machining fixture with an independent adsorption unit and a ceramic compensator, the deformation and pollution problems of the traditional process are thoroughly solved through a coupling process chain of the six-stage progressive allowance cutting and three-time gradient heat treatment, and the self-adaptive stress homogenization clamping system of the independent adsorption unit partition vacuum adsorption and the ceramic compensator is used for controlling the integral machining deformation within 0.015mm, and the surface roughness Ra is less than or equal to 0.2 mu m, so that the cleanliness reaches Class 10.

Inventors

  • DENG LIGUANG
  • ZHENG SHENGHUA
  • ZHU WEISHENG
  • LIAO ZIJIAN
  • YE LIBIN

Assignees

  • 浙江先导精密机械有限公司

Dates

Publication Date
20260508
Application Date
20251230

Claims (10)

  1. 1. A high-precision machining process for a titanium alloy thin-wall frame assembly is characterized in that six-stage progressive allowance cutting is adopted, heat treatment is coupled with machining depth, self-adaptive stress homogenization clamping is carried out through a machining jig with an independent adsorption unit and a ceramic compensator, and the high-precision machining process comprises the following steps: S1, clamping a titanium alloy thin-wall frame assembly on a processing jig to perform rough cavity opening; s2, carrying out primary heat treatment: s3, performing secondary thickening on the titanium alloy thin-wall frame assembly; s4, semi-finishing the titanium alloy thin-wall frame assembly; s5, carrying out heat treatment for the second time: s6, performing primary finish machining on the titanium alloy thin-wall frame assembly; s7, performing secondary finish machining on the titanium alloy thin-wall frame assembly; S8, performing third heat treatment; And S9, final finishing.
  2. 2. The high-precision machining process of the titanium alloy thin-wall frame assembly is characterized in that step S1 is to perform rough cavity opening on a titanium alloy thin-wall frame assembly product, wherein single-side allowance is 3mm, a machining cutter is a hard alloy milling cutter, the rotating speed of a main shaft is 1600-2000 rpm, the feeding mode is layered milling, each layer is less than or equal to 1mm, 70% of allowance is removed rapidly, step S3 is to perform secondary rough opening on the titanium alloy thin-wall frame assembly, the single-side allowance is left to 1mm, the machining cutter is a hard alloy milling cutter, the rotating speed of the main shaft is 2200-2800 rpm, the feeding mode is contour milling with equal height and the step distance is 0.5mm.
  3. 3. The high-precision machining process of the titanium alloy thin-wall frame assembly, which is characterized by comprising the steps of carrying out vacuum annealing on the titanium alloy thin-wall frame assembly within 48 hours after rough cavity machining, carrying out furnace cooling at 700-800 ℃ for 2 hours, eliminating surface layer stress caused by rough machining, stabilizing internal tissues of a substrate, carrying out vacuum destressing annealing on the titanium alloy thin-wall frame assembly, carrying out heat preservation at 600-700 ℃ for 1.5 hours, protecting and quick cooling by argon, releasing cutting thermal stress generated by semi-finishing, controlling creep deformation of a thin-wall region, carrying out third heat treatment in step S8, carrying out vacuum ageing treatment on the titanium alloy thin-wall frame assembly, carrying out heat preservation at 520-580 ℃ for more than 1 hour, carrying out cryogenic treatment at-120+/-10 ℃ for 2 hours, eliminating micron-level residual stress, and carrying out ultrasonic vibration cleaning after the cryogenic treatment.
  4. 4. The high-precision machining process of the titanium alloy thin-wall frame assembly according to claim 1, wherein in the step S4, semi-finishing is carried out on the titanium alloy thin-wall frame assembly, the unilateral allowance is 0.5mm, a diamond coating cutter is adopted as a machining cutter, a feeding mode with the spindle rotating speed of 32000-3800 rpm is a spiral cutter feeding mode, the forward milling is mainly carried out, and 70% residual stress is released.
  5. 5. The high-precision machining process for the titanium alloy thin-wall frame assembly according to claim 1 is characterized in that in the step S6, the titanium alloy thin-wall frame assembly is subjected to primary finishing, the single-side allowance is reserved by 0.2mm, a phi 6R0.5PCD cutter is adopted as a machining cutter, the rotating speed of a main shaft is 4200-4800 rpm, the feeding mode is controlled by constant cutting force, in the step S7, the titanium alloy thin-wall frame assembly is subjected to secondary finishing, the single-side allowance is reserved by 0.1mm, the rotating speed of the main shaft is 5800-6200 rpm, and the feeding mode is micro-feeding of 0.02mm/r.
  6. 6. The high-precision machining process of the titanium alloy thin-wall frame assembly according to claim 1, wherein in the step S9, final finishing is performed by adopting a single crystal diamond cutter as a machining cutter, wherein the spindle rotation speed is 7500 rpm-8500 rpm, and the feeding mode is nano-scale cutting and finishing.
  7. 7. The high-precision machining process of the titanium alloy thin-wall frame assembly according to any one of claims 1 to 6, wherein the clamping step of the titanium alloy thin-wall frame assembly is as follows: S1, performing initial positioning, namely scanning a blank by using a 3D vision system, and identifying a deformation area; s2, performing self-adaptive clamping, namely activating vacuum to each independent adsorption unit partition, and controlling the contact pressure to be 0.1-0.3 MPa; s3, monitoring in the processing, namely detecting the surface runout of a workpiece in real time by an in-machine laser micrometer, and automatically adjusting the adsorption force when the surface runout exceeds the tolerance; and S4, unloading protection, namely gradually releasing vacuum after processing, consuming more than or equal to 30 seconds, and preventing elastic rebound.
  8. 8. A processing fixture for high-precision processing of a titanium alloy thin-wall frame assembly is characterized in that a plurality of independent adsorption units are arranged on the processing fixture, each independent adsorption unit is respectively provided with a ceramic compensator, clamping force is monitored in real time, and a stress homogenizing structure is formed on the processing fixture.
  9. 9. The fixture of claim 8, wherein the independent adsorption unit of the fixture has adsorption contact surface and clearance surface, and the adsorption contact surface has several air suction holes.
  10. 10. The fixture of claim 8 or 9, wherein the fixture comprises a second roughing fixture, a third roughing fixture, a semi-finishing fixture, and a finishing fixture.

Description

High-precision machining process and machining clamp for titanium alloy thin-wall frame assembly Technical Field The invention relates to the technical field of machining processes, in particular to a high-precision machining process and a machining clamp for a titanium alloy thin-wall frame assembly. Background As core equipment for manufacturing integrated circuits, the photoetching machine needs to have extremely high dimensional stability (form and position tolerance is less than or equal to 0.01 mm), surface quality (Ra is less than or equal to 0.4 mu m) and internal cleanliness (granularity is more than or equal to Class 100). Titanium alloy is the preferred material because of high specific strength, low thermal expansion coefficient and excellent corrosion resistance, but has the following problems of poor machinability (low heat conductivity and high chemical activity), easy deformation of thin-wall structure processing (wall thickness is usually <2mm, length-diameter ratio is more than 10:1), strong internal stress sensitivity, deformation amount of 0.3-0.5mm after traditional processing and extremely sensitivity to machine tool environment and cutting pollution. The existing processing mode adopts 2-3 times of rough finishing and single heat treatment. The existing processing method has the following problems that residual stress is concentrated, stress release after rough processing is insufficient, and dimensional drift after finish processing is out of tolerance. Clamping deformation, local stress concentration caused by clamping of a traditional pressing plate, and shape and position errors caused by elastic recovery after loosening. The cleanliness is out of control, and the cutting fluid residue reacts with titanium alloy powder to generate pollutants, so that the vacuum environment of the photoetching machine is influenced. The machining efficiency is low, the cutter is fast in abrasion due to the fact that the single allowance is too large, and the surface quality is unstable. In the prior art, for example, CN 113182896a discloses a clamping device and a clamping method for large thin-wall frame type precision casting parts, which are used for large thin-wall frame type precision casting parts and are completely different from the titanium alloy thin-wall frame assembly related to the application, so that the clamping device and the clamping method cannot be applied to the titanium alloy thin-wall frame assembly in the application. Therefore, it is necessary to design a high-precision machining process and a machining fixture for a titanium alloy thin-wall frame assembly to solve the problems of residual stress concentration, insufficient stress release after rough machining and excessive dimensional drift after finish machining in the existing machining process. Clamping deformation, local stress concentration caused by clamping of a traditional pressing plate, and shape and position errors caused by elastic recovery after loosening. The cleanliness is out of control, and the cutting fluid residue reacts with titanium alloy powder to generate pollutants, so that the vacuum environment of the photoetching machine is influenced. The machining efficiency is low, the cutter is fast in abrasion due to the fact that the single allowance is too large, and the surface quality is unstable. Disclosure of Invention The invention aims to solve the problems of the prior processing technology and provide a high-precision processing technology and a processing clamp for a titanium alloy thin-wall frame component, which aim at the problem that the deformation of the whole processing is controlled within 0.015mm through three-time gradient heat treatment, a self-adaptive clamping system and clean closed-loop control by the six-stage precision processing technology for the titanium alloy thin-wall frame component, the surface roughness Ra is less than or equal to 0.2 mu m, the cleanliness reaches Class 10, and the problems of deformation and pollution of the prior art are thoroughly solved. The technical scheme adopted for realizing the first aim of the invention is that the high-precision machining process of the titanium alloy thin-wall frame component adopts six-stage progressive allowance cutting, heat treatment and machining depth coupling, and self-adaptive stress homogenization clamping is carried out by a machining jig with an independent adsorption unit and a ceramic compensator, and the method comprises the following steps: S1, clamping a titanium alloy thin-wall frame assembly on a processing jig to perform rough cavity opening; s2, carrying out primary heat treatment: s3, performing secondary thickening on the titanium alloy thin-wall frame assembly; s4, semi-finishing the titanium alloy thin-wall frame assembly; s5, carrying out heat treatment for the second time: s6, performing primary finish machining on the titanium alloy thin-wall frame assembly; s7, performing secondary finish machining