CN116237777A - CCP (control pressure and control pressure) and laser-assisted milling method for aluminum-based silicon carbide - Google Patents

Abstract

A CCP and laser-assisted milling method for aluminum-based silicon carbide belongs to the technical field of hard and brittle materials. The SiC particles in the SiC particle reinforced aluminum matrix composite material are chemically modified by utilizing the plasma chemical reaction, and the cutting characteristics of the aluminum matrix material are changed at high temperature generated by laser, so that a high-efficiency and high-quality processing mode is realized. The method comprises the following steps: s2, setting CCP processing parameters and laser power, and adjusting the installation positions and angles of the CCP plasma generating device and the laser output device; s3, preheating and processing on the sacrificial workpiece; s4, moving the milling spindle out of the machining area to the sacrificial workpiece. Compared with a laser or electric heating auxiliary processing mode, the CCP atmospheric plasma and laser auxiliary system adopted by the invention can improve the processing precision, and the surface roughness RMS of the processed SiC particle reinforced aluminum matrix composite material can reach 20nm. The CCP plasma reaction has material selectivity, is convenient for accurately controlling the removal of SiC hard particles, and is suitable for auxiliary processing.

Description

CCP (control pressure and control pressure) and laser-assisted milling method for aluminum-based silicon carbide

Technical Field

The invention belongs to the technical field of hard and brittle materials, and particularly relates to a CCP (control P) and laser-assisted milling method for aluminum-based silicon carbide.

Background

The aluminum-based composite material has the characteristics of light weight, high hardness and the like, and is widely applied to the fields of aerospace, electronics, military and the like, but the development and application of the composite material are restricted due to the fact that the physical properties of a matrix and a reinforcing phase are greatly different, and the cutting is unstable, the cutting force is large, the surface quality is poor and the like during processing. If the traditional ultra-precise grinding and the subsequent polishing process are adopted, the problems of long processing period, damage to the processing surface and the subsurface, low work piece qualification rate and the like exist, and the actual requirements can not be met far. In the prior art, the matrix material aluminum of the SiC particle reinforced aluminum matrix composite material is heated and softened by a laser or electric heating method, so that the material is convenient to remove and cutter abrasion is reduced, but the physicochemical characteristics of SiC in the SiC particle reinforced aluminum matrix composite material are difficult to change by the laser or electric heating method, so that the SiC in the material removal is stripped from the matrix material, the processing surface is relatively poor, and the requirement of ultra-precise processing is difficult to be met.

Disclosure of Invention

The invention aims to solve the processing efficiency and quality problems of hard and brittle parts, thereby greatly shortening the processing period and effectively reducing the processing cost so as to meet the demands of the parts in the fields of aerospace, electronics, military and the like. The invention provides a CCP and laser-assisted milling method for aluminum-based silicon carbide, which utilizes a plasma chemical reaction to chemically modify SiC particles in a SiC particle reinforced aluminum-based composite material and changes the cutting characteristics of the aluminum-based material at high temperature generated by laser, thereby improving the processing efficiency, reducing the cutter abrasion and realizing a high-efficiency and high-quality processing mode.

The technical scheme adopted by the invention is as follows:

a CCP, laser-assisted milling method for aluminum-based silicon carbide, comprising the steps of:

s1, installing a milling device with a CCP plasma generating device and a laser output device;

s2, setting CCP processing parameters and laser power, and adjusting the installation positions and angles of the CCP plasma generating device and the laser output device;

s3, preheating and processing on the sacrificial workpiece;

s4, after machining is finished, the milling spindle is moved out of the machining area to the sacrificial workpiece, and the workpiece is prevented from being damaged.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention adopts atmospheric plasma and laser to assist in processing, changes the surface property of processed materials, improves milling efficiency and milling quality, reduces cutter loss, and overcomes the defects of long processing period, poor surface quality and the like in the traditional single milling mode.

2. The CCP atmospheric plasma adopted by the invention has adjustable processing state, can be adjusted according to workpieces with different components and processing characteristics, and can realize material removal through chemical reactions with different degrees, which cannot be adjusted by the traditional processing mode, and the plasma generation system basically has no loss and can be continuously and repeatedly utilized.

3. The CCP atmospheric plasma and laser auxiliary system adopted by the invention is simple to manufacture and install, basically has no loss in the processing process, can be installed repeatedly, effectively saves the processing time and improves the processing efficiency.

4. The CCP plasma and the laser auxiliary processing area adopted by the invention are always positioned in front of the milling processing area, and can be correspondingly adjusted along with the change of the milling track so as to keep the auxiliary processing area always positioned at the front end of the milling track.

5. Compared with a laser or electric heating auxiliary processing mode, the CCP atmospheric plasma and laser auxiliary system adopted by the invention can improve the processing precision, and the surface roughness RMS of the processed SiC particle reinforced aluminum matrix composite material can reach 20nm.

6. The CCP plasma reaction adopted by the invention has material selectivity, is convenient for accurately controlling the removal of SiC hard particles, is suitable for auxiliary processing, improves the processing efficiency and the processing precision, and prolongs the service life of the cutter.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic view of a milling device used in the present invention;

FIG. 3 is a schematic view of a processing track of the present invention;

FIG. 4 is a schematic diagram of a CCP processing principle;

FIG. 5 is a schematic diagram of a CCP and laser-assisted milling process;

wherein: 1. CCP plasma generating means; 2. CCP plasma generating device mounting brackets; 3. a laser output device; 4. a laser output device mounting bracket; 5. a laser source; 6. a radio frequency power supply; 7. mixing a plasma gas source; 8. milling a main shaft; 9. an ER chuck; 10. milling cutter.

Detailed Description

For a better understanding of the objects, structures and functions of the present invention, reference should be made to the following detailed description of the invention with reference to the accompanying drawings.

In the traditional milling process, for the processing of composite materials such as SiC particle reinforced aluminum matrix composite materials, the defects of unstable cutting, large cutting force, poor surface quality and the like exist due to the characteristics of the materials, and the problems of long processing period, damage to the processed surface and subsurface, low workpiece qualification rate and the like are caused. By adopting the CCP and laser-assisted milling method, before the workpiece is milled, the CCP fluorine-containing plasma is used for chemical etching, so that the silicon carbide component on the surface layer of the material reacts with the chemical active component in the plasma to generate a product which is easy to remove, thereby improving the milling performance of the material. Meanwhile, the workpiece is locally heated to a very high temperature under the action of a laser beam, and the plasticity of the material is improved by heating the material in a short time before the material is cut off, so that the yield strength is reduced below the breaking strength, the milling force is reduced, and the cutter abrasion is reduced. And photons of the laser beam can provide partial reaction energy for the plasma to accelerate the chemical reaction of the plasma and silicon carbide.

As shown in fig. 1, the CCP and laser-assisted milling method for aluminum-based silicon carbide of the present invention comprises the following steps:

s1, a milling device with a CCP plasma generating device 1 and a laser output device 3 is installed,

the CCP plasma generating device 1 and the laser output device 3 are arranged at the corresponding positions of the outer annular flange structure of the milling spindle 8 and are connected with corresponding circuits, gas circuits and laser paths, so that the reliable and stable installation of each part is ensured;

the annular flange structure of the milling spindle 8 can be rotated by a motor during machining, and the plasma generating device 1 and the laser output device 3 are mounted on the outer annular flange structure of the milling spindle 8. During machining, the plasma reaction area overlaps with the laser irradiation area, and has relatively fixed distribution positions with the milling cutter, and can be correspondingly adjusted along with the milling path.

The motor-driven annular flange structure comprises the following specific structures: the output shaft of the motor is provided with a driving gear, the annular flange structure is provided with external teeth, the motor drives the annular flange structure to rotate through the driving gear, and meanwhile, the motor is arranged on the milling spindle 8 and synchronously moves with the milling spindle 8.

The plasma and laser auxiliary processing area is always positioned in front of the milling processing area, and corresponding adjustment can be made along with the change of the milling track so as to keep the auxiliary processing area always positioned at the front end of the milling track.

S2, adjusting the CCP plasma generating device 1 and the laser output device 3, setting CCP processing parameters, laser power and other parameters, and adjusting the installation position and angle of the CCP plasma generating device to meet the processing requirements: i.e. at the front end of the milling path, at a suitable distance from the milling cutter.

Setting CCP processing parameters, laser power and other parameters to ensure that the width of a heat affected zone generated by laser on the surface of a workpiece is 1-2 mm and the depth is 0.3-0.5 mm; the chemical etching range of the plasma is 3-6 mm.

The mounting positions and angles of the CCP plasma generating device 1 and the laser output device 3 are adjusted so that the two active areas overlap and the distance between the two active areas and the milling cutter is always 5-10mm on the processing path.

S3, preheating and processing on the sacrificial workpiece;

and respectively starting the plasma reaction system and the laser generation system to preheat the plasma reaction system and the laser generation system for processing for a period of time, wherein the operation is performed on the sacrificial workpiece which is additionally arranged beside the plasma reaction system and the laser generation system, and starting a machine tool processing program to start processing after the processing is stable. During machining, the outer annular flange structure of the milling spindle 8 rotates to accommodate different milling trajectories when the trajectories change, as shown in fig. 5.

Before machining, setting the corners of the outer annular flange structures of the milling spindles 8 corresponding to different path points in a machine tool machining program.

S4, after machining is finished, the milling spindle 8 is moved out of the machining area to the sacrificial workpiece, the workpiece is prevented from being damaged, the plasma reaction system and the laser generation system are sequentially turned off, and the outer annular flange structure of the milling spindle 8 returns to the initial machining position, so that machining is finished. The specific function implementation of the invention relies on the CCP plasma generator being a capacitively coupled plasma generator, the laser generator being a carbon dioxide laser. And the CCP processing area and the laser action area are overlapped and always positioned at the front end of the milling path, and keep a constant distance from the milling cutter. The cutting performance of the matrix and the reinforcement of the SiC particle reinforced aluminum matrix composite material is changed simultaneously through the combined action of plasma and laser, and the CCP and laser assisted milling principle is shown in figure 5. And the sacrificial workpiece is placed around the processed workpiece, so that the laser is prevented from directly irradiating the workbench and damaging the workbench.

And the milling device is used for jointly assisting the milling processing by plasma and laser. The device comprises a CCP plasma generating device 1, a laser output device 3, a laser source 5, a radio frequency power supply 6, a mixed plasma gas source 7, a milling spindle 8 and a milling cutter 10; the milling cutter 10 is normally installed on the milling spindle 8 through the ER chuck 9, the CCP plasma generating device 1 and the laser output device 3 are both installed on the milling spindle 8, the plasma reaction environment generated by the CCP plasma generating device 1 and the laser light spot emitted by the laser output device 3 are ensured to be positioned in a region to be processed, the surface of a workpiece is modified before the milling cutter 10 is processed, the cutting performance of a matrix and an enhanced body of the SiC particle reinforced aluminum matrix composite material is changed simultaneously through the combined action of plasma and laser, and the processing requirements of high efficiency and high precision are realized. The CCP and laser-assisted milling principle is shown in fig. 4, and in the rotating process, the plasma reaction environment and the laser spot moment are kept in the same processing range and are close to the milling processing area. The radio frequency power supply 6 is arranged outside and connected with the CCP plasma generating device 1 through a radio frequency cable to realize energy transmission, the mixed plasma gas source 7 is connected with the CCP plasma generating device 1 through a gas pipe, and the laser source 5 transmits laser into the laser output device 3 through an optical fiber. The frequency of the radio frequency power supply 6 is 13.56MHz and the maximum power is 500W.

The parts to be processed are made of hard and brittle composite materials such as aluminum-based silicon carbide and the like.

The plasma generating mode is CCP-capacitively coupled plasma excitation, which is plasma formed by applying radio frequency current to two electrodes, namely a metal motor and a ground electrode, in a cavity of a protective shell and grounding the other electrode and reacting gas between the two electrodes. As shown in fig. 4.

Further, an annular flange structure is arranged on the outer cylindrical surface of the milling spindle 8 and is used for installing the CCP plasma generating device 1 and the laser output device 3. The CCP plasma generating device 1 is arranged on the annular flange structure of the milling spindle 8 through the CCP plasma generating device mounting bracket 2, and the laser output device 3 is arranged on the annular flange structure of the milling spindle 8 through the laser output device mounting bracket 4.

The annular flange structure of the milling spindle 8 can be driven to rotate by a motor in the machining process, so that the plasma reaction environment and the laser spots are positioned in front of the milling track of the milling cutter at any time.

Further, the mixed plasma gas source 7 comprises a reaction gas, a plasma gas and an auxiliary gas, and is a ternary gas mixing system, and the gas supply flow is 20-100L/min.

Further, the atmosphere plasma excitation gas in the mixed plasma gas source 7 is helium inert gas; the reaction gas may be a fluorine-based gas; the auxiliary gas can be oxygen, electrons generated by He ionization strike CFx, and F ions are replaced:

e ^- +CF _x →CF _x-1 +F ^-

(Energy)higher electrons can also allow the CF to _x The particles decompose into an F atom plus an electron:

e ^- +CF _x →CF _x-1 ⁺ +F+2e ^-

other recombination processes also occur:

e ^- +CF _x ⁺ →CF _x-1 +F

F ^- +CF _x +→CF _x-1 +2F

under the active atmosphere of plasma, F atoms react with the surface of the silicon-based material to generate SiF by the reaction of F and Si ₄ Volatile gas to achieve the purpose of material removal.

SiC+4F→CF ₄ +SiF ₄

The reaction mechanism of the plasma and the silicon-based material is shown in fig. 4.

Further, the laser source 5 is a large-spot CO ₂ Pulsed laser sources.

It will be understood that the invention has been described in terms of several embodiments, and that various changes and equivalents may be made to these features and embodiments by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (9)

1. A CCP and laser-assisted milling method for aluminum-based silicon carbide is characterized in that: the method comprises the following steps:

s1, installing a milling device with a CCP plasma generating device (1) and a laser output device (3);

s2, setting CCP processing parameters and laser power, and adjusting the installation positions and angles of the CCP plasma generating device (1) and the laser output device (3);

s3, preheating and processing on the sacrificial workpiece;

s4, after machining is finished, the milling spindle (8) is moved out of the machining area to the sacrificial workpiece, and damage to the workpiece is prevented.

2. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 1, wherein: in the S1, a CCP plasma generating device (1) and a laser output device (3) are arranged on a milling main shaft (8) of the milling device and are connected with a corresponding circuit, a corresponding gas circuit and a corresponding laser light path, so that reliable and stable installation of each part is ensured.

3. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 1, wherein: in the step S2, CCP processing parameters and laser power are set so that the width of a heat affected zone generated on the surface of a workpiece by laser is 1-2 mm and the depth is 0.3-0.5 mm; the chemical etching range of the plasma is 3-6 mm.

4. A CCP, laser-assisted milling method for aluminum-based silicon carbide according to claim 3, characterized by: in the step S2, the installation positions and angles of the CCP plasma generating device (1) and the laser output device (3) are adjusted so that the action areas of the CCP plasma generating device and the laser output device overlap, and the overlapping action areas of the CCP plasma generating device and the laser output device and the milling cutter (10) keep a constant distance from the milling cutter (10) within a range of 5-10mm in front of a machining path.

5. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 1, wherein: s3, preheating and processing on a sacrificial workpiece, wherein the preheating and processing specifically comprises the following steps: and respectively starting the plasma reaction system and the laser generation system to preheat the plasma reaction system and the laser generation system for a period of time, wherein the operation is performed on an additional sacrificial workpiece beside the plasma reaction system and the laser generation system, starting a machine tool machining program after the machining is stable, and starting the machining, wherein in the machining process, when the track is changed, the outer annular flange structure of the milling spindle (8) rotates so as to adapt to different milling tracks.

6. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 5, wherein: and (3) setting the corners of the outer annular flange structures of the milling spindles (8) corresponding to different path points in a machine tool machining program before machining in the step (S3).

7. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 1, wherein: and S4, after the milling spindle 8 is moved out of the processing area to the sacrifice workpiece, the plasma reaction system and the laser generation system are sequentially turned off, and the outer annular flange structure of the milling spindle 8 returns to the initial processing position, so that the processing is finished.

8. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 1, wherein: the milling device comprises a CCP plasma generating device (1), a laser output device (3), a laser source (5), a radio frequency power supply (6), a mixed plasma gas source (7), a milling spindle (8) and a milling cutter (10); the milling cutter (10) is arranged on the milling spindle (8), the CCP plasma generating device (1) and the laser output device (3) are arranged on the milling spindle (8) and ensure that a plasma reaction environment and a laser spot are located in a region to be processed, the surface of a workpiece is modified before the milling cutter (10) is processed, the radio frequency power supply (6) is connected with the CCP plasma generating device (1) to realize energy transmission, the mixed plasma gas source (7) is connected with the CCP plasma generating device (1), and the laser source (5) transmits laser to the laser output device (3).

9. A CCP, laser assisted milling method for aluminum-based silicon carbide according to claim 8, wherein: the atmosphere plasma excitation gas in the mixed plasma gas source (7) is helium inert gas, the reaction gas is fluorine-based gas, the auxiliary gas is oxygen, electrons generated by He ionization strike CFx, and F ions are replaced:

e ^- +CF _x →CF _x-1 +F ^-

electrons with higher energy can also let CF _x The particles decompose into an F atom plus an electron:

e ^- +CF _x →CF _x-1 ⁺ +F+2e ^-

other recombination processes also occur:

e ^- +CF _x ⁺ →CF _x-1 +F

F ^- +CF _x +→CF _x-1 +2F

under the active atmosphere of plasma, F atoms react with the surface of the silicon-based material to generate SiF by the reaction of F and Si ₄ Volatile gas, the purpose of removing materials is achieved,

SiC+4F→CF ₄ +SiF ₄ 。

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