A precision milling method for aluminum matrix silicon carbide particle composites

Abstract

A precision milling method for an aluminum matrix silicon carbide particle composite material, which is a milling method for a low volume fraction annealed silicon carbide particle reinforced aluminum matrix composite material. The milling process is divided into rough machining and finish machining: Use a two-flute milling cutter with a diameter of 10 mm to perform rough machining on the original surface. At this time, the machining depth should be controlled between 0.5 mm and 1 mm as much as possible, and it is completed in 5 to 10 times to reduce cutting heat. The rough machining is mainly to level the machining surface. After rough machining, enter finish machining. An oil film is formed on the machining surface to play a role in lubrication and wear reduction, and assist the tool to remove the chips attached to the machining surface. After the oil, water and vapor are vaporized, a large amount of cutting heat is carried away, improving the tool life and surface accuracy. After machining is completed, the workpiece needs to be placed in natural conditions for half a year to reduce residual stress. The method of the present invention effectively improves the tool life, reduces the processing cost, helps energy conservation and emission reduction, and effectively avoids waste.

Description

Technical Field

[0001] The present invention relates to a precision milling method for a hard-textured composite metal material, and particularly to a precision milling method for an aluminum matrix silicon carbide particle composite material. Background Art

[0002] The SiCp / Al composite material has an aluminum alloy as the matrix phase and silicon carbide particles with an appropriate volume fraction as the reinforcement phase. This material has excellent properties such as high specific strength, good dimensional stability, low coefficient of thermal expansion, good thermal conductivity, wear resistance, and corrosion resistance, and is suitable for applications in the aerospace field.

[0003] Since the silicon carbide particles in the aluminum matrix silicon carbide particle-reinforced composite material are relatively hard, they have a greater impact on tool wear during processing, increasing the processing difficulty, reducing the surface quality of the processing, and causing large fluctuations in cutting stress due to the particles during cutting. The residual stress after processing will also affect the quality of the workpiece, and special treatment of the processed material is required. Summary of the Invention

[0004] The purpose of the present invention is to provide a precision milling method for an aluminum matrix silicon carbide particle composite material. Through the comprehensively designed milling method, the present invention can protect the tool, extend the tool life, make the chip removal more smooth, reduce the residual stress inside the part by natural aging, improve the dimensional accuracy of the workpiece, and increase its durability. An excellent processing method is proposed for the processing of low-volume-fraction annealed silicon carbide particle-reinforced aluminum matrix composites, meeting the quality requirements for the precision processing of special materials.

[0005] The purpose of the present invention is achieved through the following processing scheme:

[0006] A precision milling method for an aluminum matrix silicon carbide particle composite material, the method comprising the following steps:

[0007] Step 1: Use a diamond double-edge milling cutter for processing and leveling; the roughing parameters are: cutting speed is 376.8 m / min, feed speed is 200 mm / min, and cutting depth is 0.5 mm; or the processing depth is selected between 5 mm and 10 mm and completed in 5 to 10 times;

[0008] Step 2: Use a diamond single-edge milling cutter for finish machining, supplemented by minimum quantity lubrication of an oil-water mixture; the finish machining parameters are: cutting speed is 47.1 m / min, feed speed is 10 mm / min, and cutting depth is 80 μm;

[0009] Step 3: After the processing is completed, place it in natural conditions for half a year to eliminate the residual stress that appears after processing.

[0010] The described precision milling method for aluminum matrix silicon carbide particulate composites, the composite material is a low volume fraction silicon carbide particulate reinforced aluminum matrix composite, its particulate volume fraction is 20%, the material as the matrix phase is Al2009, the material as the reinforcing phase is SiC, and its average diameter is 7μm.

[0011] The described precision milling method for aluminum matrix silicon carbide particulate composites, the machining leveling is carried out using a diamond two-edge milling cutter with a large diameter of 10mm, and then a diamond single-edge milling cutter with a diameter of 1.5mm is used for finish machining.

[0012] The described precision milling method for aluminum matrix silicon carbide particulate composites, the rough machining parameters are: cutting speed 376.8m / min, feed speed 200mm / min, cutting depth 0.5mm; the finish machining cutting parameters are cutting speed 47.1m / min, feed speed 10mm / min, cutting depth 80μm.

[0013] The described precision milling method for aluminum matrix silicon carbide particulate composites, the lubrication uses an oil-water mixture, which is atomized through compressed air to form an oil film on the machining surface, so that the cutting chips are discharged and the cutting heat is dissipated.

[0014] The advantages and effects of the present invention are:

[0015] The present invention makes full preparations for accurate positioning in finish machining through rough machining. The minimum quantity lubrication with an oil-water mixture can not only protect the tool and extend the tool life, but also make the chip evacuation smoother and the machining surface flatter. Finally, through natural aging, the residual stress inside the part is reduced, the dimensional accuracy of the workpiece is improved, and its durability is also increased. The combined action of the above comprehensive factors is of great help to improving the machining surface quality of the low volume fraction annealed silicon carbide particulate reinforced aluminum matrix composite. Brief Description of the Drawings

[0016] Figure 1 Schematic diagram of milling machining of the low volume fraction annealed silicon carbide particulate reinforced aluminum matrix composite according to the embodiment of the present invention:

[0017] Figure 2 Finite element simulation diagram of the material milling process according to the embodiment of the present invention;

[0018] Figure 3 2D surface topography diagram of the material after milling machining according to the embodiment of the present invention;

[0019] Figure 4 Electron microscope detection result diagram of the subsurface after the material milling machining according to the embodiment of the present invention. Embodiment

[0020] The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

[0021] A machining method for a milled low-volume-fraction annealed silicon carbide particle-reinforced aluminum matrix composite material of the present invention includes the following steps:

[0022] Step 1: Use a large-diameter diamond two-edge milling cutter for machining and leveling. The rough machining parameters are: cutting speed of 376.8 m / min, feed speed of 200 mm / min, and cutting depth of 0.5 mm. If necessary, the machining depth can be selected between 5 mm and 10 mm and completed in 5 to 10 times.

[0023] Step 2: Use a small-diameter diamond single-edge milling cutter for finish machining, supplemented by minimum quantity lubrication of a mixture of oil and water. The finish machining parameters are: cutting speed of 47.1 m / min, feed speed of 10 mm / min, and cutting depth of 80 μm.

[0024] Step 3: After machining, it is necessary to place it under natural conditions for half a year to eliminate the residual stress that appears after machining.

[0025] The particle volume fraction of the low-volume-fraction annealed silicon carbide particle-reinforced aluminum matrix composite material is 20%, the reinforcing phase is composed of particles with an average diameter of 7 μm, and the matrix material is Al2009.

[0026] Use a 10-mm diamond two-edge milling cutter for rough machining to find the plane, and then use a 0.8-mm diamond single-edge milling cutter for finish machining.

[0027] The lubrication method is a mixture of oil and water lubrication. The oil and water are atomized by compressed air to form an oil film on the machining surface, which plays a role in lubrication and wear reduction and assists the tool in removing the chips attached to the machining surface.

[0028] The method for eliminating the residual stress after machining is natural aging treatment. By exposing the parts to the natural environment for half a year, the dimensional accuracy is stabilized.

[0029] The finish machining cutting parameters are cutting speed of 47.1 m / min, feed speed of 10 mm / min, cutting depth of 80 μm, and surface roughness of 0.029 μm.

[0030] Such as Figure 1As shown in the figure, in the machining of a low-volume-fraction annealed silicon carbide particle-reinforced aluminum matrix composite, first, rough milling and leveling are carried out with a milling cutter with a diameter of 10 mm, and then finish milling is carried out with a milling cutter with a diameter of 1.5 mm to machine the low-volume-fraction silicon carbide particle-reinforced aluminum matrix composite. During the finish machining process, minimum quantity lubrication with a mixture of oil and water is required to reduce the generation of cutting heat and accelerate the removal of chips, so as to obtain better surface quality. After the machining is completed, it is placed in the natural environment for half a year to reduce the residual stress in a low-cost way. The specific implementation process is as follows:

[0031] As Figure 2 shown in the figure, before the milling machining, a finite element simulation software is used to simulate the cutting process to obtain the failure forms of the particles and the matrix during the machining process. The main failures that occur in the aluminum matrix silicon carbide particle-reinforced composite are plastic deformation and brittle fracture. The matrix is a plastic material. After plastic deformation occurs, the surface of the machined material becomes uneven. The particles are brittle materials and are crushed by the cutting tool during machining, and some or all of the particles are pulled out, resulting in pits.

[0032] The machining starts with a two-edge milling cutter with a diameter of 10 mm for leveling and initially removing the material. At this time, the surface quality is not high. The cutting parameters for rough machining are: cutting speed is 376.8 m / min, feed speed is 200 mm / min, and cutting depth is 0.5 mm. Then, a single-edge milling cutter with a diameter of 1.5 mm is used to finish machine the material, and minimum quantity lubrication with a mixture of oil and water is required. During finish machining, in order to ensure the product quality, it is necessary to timely remove the chips, and it is also necessary to cool the cutting tool to extend the tool life and improve the production efficiency. Minimum quantity lubrication not only saves costs but also can obtain good results. The cutting parameters for finish machining are: cutting speed is 47.1 m / min, feed speed is 10 mm / min, and cutting depth is 80 μm.

[0033] As Figure 3 shown in the figure, from the 2D surface topography map of the milled surface after finish machining and the real surface detection results, it can be known that the machined surface is relatively flat and there are few defects. Taking the average value of the three roughness test results, the surface roughness can be obtained as 0.029 μm. It can also be seen from the figure that the main damages generated are pits and burrs caused by plastic deformation, which are consistent with the finite element simulation results.

[0034] As Figure 4 shown in the figure, it can be seen from the subsurface test results of the material that cracks will be generated when the particles in the material are extruded, and it can also be seen that the surface is relatively flat, which has met the quality requirements of industrial production.

Claims

1. A precision milling method for aluminum matrix silicon carbide particulate composite material, characterized in that, The method includes the following steps: Step 1: Use a diamond two-edge milling cutter for machining and leveling; the rough machining parameters are: cutting speed is 376.8 m / min, feed speed is 200 mm / min, and cutting depth is 0.5 mm; Step 2: Use a diamond single-edge milling cutter for finish machining, assisted by minimum quantity lubrication of oil-water mixture; the finish machining parameters are: cutting speed is 47.1 m / min, feed speed is 10 mm / min, and cutting depth is 80 μm; Step 3: After machining, place it under natural conditions for half a year to eliminate the residual stress generated after machining; The composite material is a low-volume fraction annealed silicon carbide particle-reinforced aluminum matrix composite material, its particle volume fraction is 20%, the material as the matrix phase is Al2009, the material as the reinforcement phase is SiC, and its average diameter is 7 μm; The machining and leveling is carried out using a diamond two-edge milling cutter with a diameter of 10 mm, and then finish machining is carried out using a diamond single-edge milling cutter with a diameter of 0.8 mm; The minimum quantity lubrication uses oil-water mixture lubrication, and the atomization of oil and water is completed through compressed air to form an oil film on the machining surface, so that the cutting chips are discharged and the cutting heat is dissipated.

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