A positioning machining method for a SiC fiber reinforced metal matrix composite shaft part

Abstract

The present application relates to the field of metal matrix composite structure processing and preparation, in particular to a positioning processing method for SiC fiber reinforced metal matrix composite shaft-shaped parts, which is suitable for the preparation and processing of metal matrix composite shaft-shaped parts. With the consistency of the axial coaxiality of the composite reinforcement in the shaft-shaped part as the target, and the minimum diagonal deviation of the outer contour of the shaft-shaped part and the minimum standard deviation of the reinforcement sleeve thickness as the benchmark positioning principle, the composite shaft-shaped part is positioned and processed through workpiece outer dimension detection, preliminary non-destructive positioning of the reinforcement, preliminary positioning of the processing benchmark, preliminary turning processing, secondary non-destructive positioning of the reinforcement, secondary positioning of the processing benchmark, and workpiece finishing, so as to solve the technical problems that the volume of the metal matrix composite shaft-shaped part will shrink after densification forming, causing fluctuations in the outer dimension, which makes the positioning of the processing benchmark difficult, easily leading to deviation of the reinforcement and the outer sleeve axis, and even causing the reinforcement to be exposed and damaged.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite structural component processing and fabrication, specifically a method for positioning and processing SiC fiber reinforced metal matrix composite shaft components, applicable to the preparation and processing of metal matrix composite shaft components. Background Technology

[0002] Continuous SiC fiber-reinforced metal matrix composites possess high specific strength, high specific stiffness, good high temperature resistance, creep resistance, and fatigue resistance, making them ideal high-temperature lightweight structural materials. Shaft-type structural components made from this material have clear application prospects in aerospace and other fields.

[0003] SiC fiber-reinforced metal matrix composite shafts are typically fabricated using the precursor fiber preform method. This method offers advantages such as unrestricted matrix alloy types and compositions, precise control of fiber volume fraction, and a degree of weaving capability, making it particularly suitable for fabricating complex-shaped structural components like shafts. The main process flow is as follows: First, the matrix alloy is coated onto the surface of SiC fibers using physical vapor deposition to create composite precursor fibers. Then, the precursor fibers are woven and laid inside the preform sheath. Next, the components of the preform sheath are assembled and fixed. Finally, the structural component is densified and formed through high-temperature pressing.

[0004] Because the volume of metal matrix composite shaft parts shrinks and their dimensions fluctuate after densification molding, it is difficult to position the machining reference. This can easily lead to deviations between the reinforcement and the outer sleeve axis, or even technical problems such as exposed or damaged reinforcement, which seriously affect the performance of the shaft parts. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts. This method can effectively solve the problems of difficult datum positioning and large deformation after machining in the current machining process of SiC fiber-reinforced titanium matrix composite shaft parts.

[0006] The technical solution of this invention is:

[0007] A method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts comprises workpiece dimensional inspection, preliminary non-destructive positioning of the reinforcement, preliminary positioning of the machining datum, preliminary turning, secondary non-destructive positioning of the reinforcement, secondary positioning of the machining datum, and workpiece finishing processes. The preliminary positioning device for the machining datum of the shaft part includes a shaft part, a four-jaw chuck, a support plate, and a top shaft. The specific structure is as follows: the shaft part is a SiC fiber-reinforced metal matrix composite shaft part, containing a reinforcement. One end of the shaft part has a clamping end, which is connected and fixed to the four-jaw chuck. The other end of the shaft part has a support end, and the top shaft is in close contact with the support end through the support plate.

[0008] The specific implementation of the SiC fiber reinforced metal matrix composite shaft part positioning and machining method is as follows: Since the external dimensions of the formed SiC fiber reinforced metal matrix composite shaft part fluctuate, it is necessary to use coordinate measuring machine or high-precision three-dimensional copying detection method to perform all-round dimension measurement. The measurement results serve as the basic data for the initial positioning of the machining datum.

[0009] The aforementioned SiC fiber-reinforced metal matrix composite shaft positioning and processing method includes the following specific implementation for the preliminary non-destructive positioning of the reinforcement: The internal reinforcement of the shaft is non-destructively positioned using an ultrasonic thickness gauge or ultrasonic C-scan high-precision ultrasonic positioning method. The positioning result is used as the basic data for the preliminary positioning of the processing reference.

[0010] The specific implementation of the SiC fiber-reinforced metal matrix composite shaft positioning and machining method is as follows:

[0011] (1) Use a four-jaw chuck to fix the mounting end of one end of the shaft-shaped part, and use a flat top shaft and a top shaft to support the other end of the shaft-shaped part;

[0012] (2) Use a dial indicator to measure the outer surface of the shaft at the center and both ends of the reinforcement. Adjust the chuck according to the principle of minimizing diagonal deviation. At the same time, combine the workpiece shape and size detection and the basic data of the reinforcement's preliminary non-destructive positioning to perform preliminary positioning and processing of the reference surface.

[0013] The aforementioned SiC fiber reinforced metal matrix composite shaft positioning and machining method includes the following preliminary turning process: the outer surface of the shaft after preliminary positioning of the machining datum is turned until there are no original marks on its outer surface and it is a regular shaft, then the machining is stopped.

[0014] The aforementioned SiC fiber-reinforced metal matrix composite shaft positioning and machining method specifically implements the secondary non-destructive positioning of the reinforcement as follows: The internal reinforcement of the shaft after preliminary turning is non-destructively positioned using an ultrasonic thickness gauge or ultrasonic C-scan high-precision ultrasonic positioning method, and the positioning result is used as the basic data for secondary positioning of the machining reference.

[0015] The aforementioned method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts involves the following specific implementation of secondary positioning of the machining datum: Based on the measurement data of secondary non-destructive positioning of the reinforcement, the machining datum is adjusted according to the principle of minimizing the standard deviation of the reinforcement sheath thickness.

[0016] The SiC fiber reinforced metal matrix composite shaft positioning and machining method described herein includes the following specific implementation for workpiece finishing: the shaft after datum adjustment is turned, milled or ground and polished. During the machining process, the size and stress changes of the composite shaft need to be monitored, and stress relief heat treatment is performed as needed to reduce or eliminate machining stress.

[0017] The design concept of this invention:

[0018] This invention aims to ensure the axial coaxiality of the composite material reinforcement within the shaft-shaped component. It uses the principles of minimizing the diagonal deviation of the shaft-shaped component's outer contour and minimizing the standard deviation of the reinforcement sheath thickness as the benchmark positioning principle. The process involves several steps, including workpiece dimensional inspection, preliminary non-destructive positioning of the reinforcement, preliminary positioning of the machining benchmark, preliminary turning, secondary non-destructive positioning of the reinforcement, secondary positioning of the machining benchmark, and final machining of the workpiece. This addresses the technical problems arising from the shrinkage and dimensional fluctuations in metal matrix composite shaft-shaped components after densification, which makes machining benchmark positioning difficult, easily leading to deviations between the reinforcement and the outer sheath axis, and even resulting in exposed or damaged reinforcement.

[0019] The advantages and beneficial effects of this invention are:

[0020] 1. The machining reference positioning method provided in this invention is beneficial to improving the positioning and machining efficiency of metal matrix composite shaft parts.

[0021] 2. The machining reference positioning method provided in this invention is beneficial to improving the performance consistency of metal matrix composite shaft parts.

[0022] 3. The machining datum positioning method provided in this invention is generally applicable to the positioning and machining of shaft-shaped parts made of metal matrix composite materials.

[0023] 4. The machining reference positioning method provided in this invention is simple, clear, and easy to implement. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the machining and mounting of the shaft-shaped parts involved in this invention.

[0025] Figure 2 This is a flowchart of the positioning and machining process for the shaft-shaped parts involved in this invention.

[0026] Figure 1 Chinese figure reference numerals: 1. Shaft-shaped component; 1.1. Reinforcing body; 1.2. Mounting end; 1.3. Support end; 2. Four-jaw chuck; 3. Support plate; 4. Top shaft. Detailed Implementation

[0027] For clarity and accuracy, the invention will be described below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the shaft-shaped component processing and clamping device of the present invention mainly includes a shaft-shaped component 1, a four-jaw chuck 2, a support plate 3, and a top shaft 4. The specific structure is as follows: the shaft-shaped component 1 is a SiC fiber-reinforced metal matrix composite shaft-shaped component. The shaft-shaped component 1 is provided with a reinforcement 1.1. One end of the shaft-shaped component 1 is provided with a clamping end 1.2. The shaft-shaped component 1 is connected and fixed to the four-jaw chuck through the clamping end 1.2. The other end of the shaft-shaped component 1 is provided with a support end 1.3. The top shaft 4 is in close contact with the support end 1.3 through the support plate 3.

[0029] like Figures 1-2 As shown, this invention provides a method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts, which consists of the following steps: workpiece dimensional inspection, preliminary non-destructive positioning of the reinforcement, preliminary positioning of the machining datum, preliminary turning, secondary non-destructive positioning of the reinforcement, secondary positioning of the machining datum, and workpiece finishing. The specific contents of each step are as follows:

[0030] 1. Inspection of workpiece external dimensions

[0031] Since the external dimensions of the molded SiC fiber reinforced metal matrix composite shaft part 1 vary, it is necessary to use three-coordinate measurement or high-precision three-dimensional copying and other detection methods to conduct all-round dimensional measurement. The measurement results serve as the basic data for the initial positioning of the machining datum.

[0032] 2. Preliminary non-destructive positioning of the reinforcement

[0033] High-precision ultrasonic positioning methods such as ultrasonic thickness gauge and ultrasonic C-scan were used to perform non-destructive positioning of the internal reinforcement 1.1 of the shaft part 1. The positioning results are used as the basic data for the preliminary positioning of the machining datum.

[0034] 3. Preliminary positioning of machining datum

[0035] (1) Use a four-jaw chuck 2 to fix the mounting end 1.2 of one end of the shaft-shaped part 1, and use a flat support plate 3 and a top shaft 4 to support the other end 1.3 of the shaft-shaped part 1;

[0036] (2) Use dial indicators and other measuring tools to measure the outer surface of the shaft parts 1 corresponding to the center and both ends of the reinforcement 1.1 respectively. Adjust the four-jaw chuck 2 according to the principle of minimizing diagonal deviation. At the same time, combine the theoretical data of workpiece shape dimension detection and preliminary non-destructive positioning of the reinforcement to perform preliminary positioning of the reference machining reference.

[0037] 4. Preliminary turning process

[0038] After the machining datum is initially positioned, the outer surface of the shaft part 1 is machined by turning until there are no original marks on its outer surface and it is a regular shaft. Then the machining stops.

[0039] 5. Secondary non-destructive positioning of the reinforcement

[0040] The internal reinforcement 1.1 of the shaft part 1 after preliminary turning was repositioned using high-precision ultrasonic positioning methods such as ultrasonic thickness gauge and ultrasonic C-scan. The positioning results of this time are used as theoretical data for secondary positioning of machining reference.

[0041] 6. Secondary positioning of machining datum

[0042] Based on the measurement data of the secondary non-destructive positioning of the reinforcement, the processing datum is adjusted according to the principle of minimizing the standard deviation of the reinforcement sheath thickness.

[0043] 7. Finishing of workpieces

[0044] After the datum is adjusted, the shaft is machined by turning, milling and polishing. During the machining process, the size and stress changes of the composite material shaft are monitored, and stress relief heat treatment is performed as needed to reduce or eliminate machining stress.

[0045] The results show that the present invention can achieve precise machining of SiC fiber reinforced metal matrix composite shaft parts, providing technical support for the engineering application of SiC fiber reinforced metal matrix composite shaft parts.

Claims

1. A method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts, characterized in that, It consists of workpiece external dimension inspection, preliminary non-destructive positioning of the reinforcement, preliminary positioning of the machining datum, preliminary turning, secondary non-destructive positioning of the reinforcement, secondary positioning of the machining datum, and workpiece finishing processes; among them, the preliminary positioning device for the machining datum of the shaft part includes a shaft part, a four-jaw chuck, a support plate, and a top shaft, with the following specific structure: the shaft part is a SiC fiber reinforced metal matrix composite shaft part, which contains a reinforcement. One end of the shaft part has a mounting end, which is connected and fixed to the four-jaw chuck through the mounting end. The other end of the shaft part has a support end, and the top shaft is in close contact with the support end through the support plate; The preliminary positioning of the machining datum is implemented as follows: (1) Use a four-jaw chuck to fix the mounting end of one end of the shaft-shaped part, and support the other end of the shaft-shaped part by a support plate and a top shaft; (2) Use a dial indicator to measure the outer surface of the shaft at the center and both ends of the reinforcement, adjust the chuck according to the principle of minimizing diagonal deviation, and combine the workpiece shape dimension detection and the basic data of the initial non-destructive positioning of the reinforcement to perform the preliminary positioning and processing of the reference surface; The secondary positioning of the processing datum is implemented as follows: Based on the measurement data of the secondary non-destructive positioning of the reinforcement, the processing datum is adjusted according to the principle of minimizing the standard deviation of the reinforcement sheath thickness; The specific implementation of workpiece external dimension inspection is as follows: Since the external dimension of the formed SiC fiber reinforced metal matrix composite shaft part fluctuates, it is necessary to use coordinate measuring machine or high-precision three-dimensional copying inspection method to conduct all-round dimension measurement. The measurement results serve as the basic data for the initial positioning of the machining datum. The specific implementation of the preliminary non-destructive positioning of the reinforcement is as follows: The internal reinforcement of the shaft part is non-destructively positioned using an ultrasonic thickness gauge or ultrasonic C-scan high-precision ultrasonic positioning method. The positioning results are used as the basic data for the preliminary positioning of the machining datum. The specific implementation of the secondary non-destructive positioning of the reinforcement is as follows: The internal reinforcement of the shaft part after preliminary turning is non-destructively positioned using an ultrasonic thickness gauge or ultrasonic C-scan high-precision ultrasonic positioning method. The positioning result is used as the basic data for secondary positioning of the machining datum.

2. The method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts according to claim 1, characterized in that, The preliminary turning process is implemented as follows: After the machining datum is initially positioned, the outer surface of the shaft is turned until there are no original marks on the outer surface and the shaft is a regular shape. Then the machining is stopped.

3. The method for positioning and machining SiC fiber-reinforced metal matrix composite shaft parts according to claim 1, characterized in that, The specific implementation of workpiece finishing is as follows: the shaft-shaped parts after the datum adjustment are turned, milled or ground and polished. During the processing, the size and stress changes of the composite material shaft-shaped parts need to be monitored, and stress relief heat treatment is carried out according to the specific situation to reduce or eliminate the processing stress.

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