A multi-energy field coupling chemical mechanical polishing equipment and method for large-volume aperture ratio thin-wall semi-closed complex structure parts

Abstract

The present application relates to a kind of large volume aperture ratio thin-walled semi-closed complex structure parts of multi-energy field coupling chemical mechanical polishing equipment and method.It includes rack, spindle system, polishing cylinder, multi-field trigger device and numerical control system, spindle system is connected with the clamp for clamping to be polished piece, spindle system is used to adjust the spatial position of spindle, so that to be polished piece enters into polishing cylinder and is immersed in polishing liquid, polishing cylinder is used to contain chemical mechanical polishing liquid and magnetic abrasive, the multi-field trigger device includes at least one of ultrasonic generator, magnetic field generating device, light source, before processing, the entrance of to-be-polished part is added with the preset amount of chemical mechanical polishing liquid and magnetic abrasive and keeps sealed state in polishing process.The present application is mainly removed by chemical dissolution, and the removal of oxide film and passivation film by micro abrasive under the action of fluid pressure is auxiliary, and the surface of part is scratch-free, and the possibility of crack and fatigue source generated by cyclic stress is excluded.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machining manufacturing, in particular, especially relates to a multi-energy field coupling chemical mechanical polishing equipment and method for large-volume aperture ratio thin-walled semi-closed complex structure parts. BACKGROUND

[0002] The large-volume aperture ratio thin-walled semi-closed complex structure parts usually have defects such as weight out-of-tolerance, surface roughness, and poor mechanical properties, but as important parts in aerospace equipment, they have high requirements for size accuracy, surface quality, and assembly accuracy. Because of the semi-closed complex structure of the large-volume aperture ratio thin-walled parts, the wall thickness is very small, and only the inlet and outlet are open, so the traditional manual polishing, soft abrasive belt polishing, robot polishing, and air bag polishing methods cannot be used. At present, the inner surface of the large-volume aperture ratio thin-walled semi-closed complex structure parts at home and abroad usually adopts chemical polishing, electrochemical polishing, abrasive flow polishing, and blowing high-pressure gas to remove the defects such as powder adhesion on the inner surface of the parts. However, chemical polishing will lose the original size of the parts, electrolytic polishing is difficult to obtain a smooth surface on the rough inner surface, and abrasive flow polishing process is prone to cause deformation of the thin-walled structure; high-pressure gas cannot completely remove the defects on the inner surface of the parts, and the inner surface roughness is high and the surface quality is poor. For magnetic flow polishing, the complex dot matrix structure inside the large-volume aperture ratio thin-walled parts hinders the flow of magnetic abrasive, and the non-uniform flow field acting on the inner wall of the thin-walled parts will also change the shape and position accuracy, making it difficult to avoid over-polishing / under-polishing. The current polishing technology cannot / fails to polish the semi-closed inner wall of the large-volume aperture ratio thin-walled parts quickly and non-destructively, which greatly affects the polishing efficiency and quality. SUMMARY

[0003] According to the above technical problems, a multi-energy field coupling chemical mechanical polishing equipment and method for large-volume aperture ratio thin-walled semi-closed complex structure parts are provided, which realizes the surface treatment of the large-volume aperture ratio semi-closed complex structure parts by using composite energy field assisted chemical mechanical polishing.

[0004] The technical means adopted by the present application are as follows:

[0005] The application discloses a multi-energy field coupling chemical mechanical polishing equipment for a large-volume-aperture-ratio thin-wall semi-closed complex structure part, which comprises a rack, a spindle system, a polishing cylinder, a multi-field triggering device and a numerical control system, the inner and outer walls of a part to be polished need to be polished, and the workpiece is a semi-closed structure, only two openings of an inlet and an outlet are opened, the spindle system is connected with a clamp for clamping the part to be polished, the spindle system is used for adjusting the spatial position of a spindle, so that the part to be polished enters the polishing cylinder and is immersed in polishing liquid, the polishing cylinder is used for containing chemical mechanical polishing liquid and magnetic abrasive, the multi-field triggering device comprises at least one of an ultrasonic generator, a magnetic field generating device and a light source, so that the multi-field triggering device has at least one of auxiliary processing energy fields of ultrasonic fields, magnetic fields and light fields, the numerical control system is connected with the spindle system and the multi-field triggering device, and is used for controlling the parameters of ultrasonic frequency, amplitude and magnetic field intensity in the polishing process, before processing, a preset amount of chemical mechanical polishing liquid and magnetic abrasive are added into the inlet of the part to be polished, and a sealed state is kept in the polishing process.

[0006] Further, the polishing liquid circulation system is connected with the polishing cylinder, is used for recycling, filtering and storing the abrasive, and realizes recycling of the abrasive.

[0007] Further, the spindle system comprises a Z-direction moving guide rail, a Y-direction moving guide rail, a deflection box and a spindle, the Z-direction moving guide rail and the Y-direction moving guide rail are connected, are used for providing the spindle with translational degrees of freedom in Z and Y directions, the deflection box is used for realizing swing of the spindle around an X axis, and the spindle is fixed on the deflection box, realizes rotational degrees of freedom of the Z axis, the clamp is installed at the bottom of the spindle through a quick-change joint, is used for fixing the workpiece, and different clamps are replaced according to different parts.

[0008] Further, the ultrasonic generator is installed on the spindle, and is used for providing the spindle with Z-direction ultrasonic vibration.

[0009] Further, the polishing cylinder is a top-opened cylindrical structure, is made of non-magnetic corrosion-resistant material, contains the chemical mechanical polishing liquid and the magnetic abrasive in the inside during polishing, and is provided with a polishing cylinder support at the bottom periphery and is installed on the bed; the polishing cylinder is provided with a liquid outlet and a liquid inlet, which are connected with the polishing liquid circulation system; and the inside of the polishing cylinder is provided with a stirrer, which is used for stirring the abrasive in the polishing cylinder, so that the polishing liquid is relatively uniformly mixed, and the abrasive particles are prevented from depositing at the bottom of the polishing cylinder.

[0010] Further, the magnetic field generating device comprises a soft iron core, a plurality of electromagnetic coils wound in multiple directions and an adjustable power DC power supply, each electromagnetic coil is powered by the adjustable power DC power supply, the soft iron core is a cylindrical thin-walled structure with open top and bottom, and is detachably nested on the outer wall of the polishing cylinder and used for enhancing the magnetic field generated by the electromagnetic coils, the electromagnetic coils are in multiple groups and have different installation modes, the electromagnetic coils installed in different directions are used for generating electromagnetic fields in different directions inside the polishing cylinder, each direction of the electromagnetic coils is independently powered, and each electromagnetic coil in the same direction is also independently powered, different voltages, different currents and different directions of the DC power are controlled during the polishing process to generate electromagnetic fields with different intensities and different directions in different areas inside the polishing cylinder, and then the magnetic field force is controlled to drive the magnetic abrasive to move inside the polishing cylinder.

[0011] Further, the light source is detachably mounted on the bed body, and is replaced by any one of a laser light source, an infrared light source or an ultraviolet light source according to processing requirements, and the light source is used for promoting the chemical reaction between the chemical mechanical polishing liquid and the workpiece surface to generate an oxide film on the workpiece surface.

[0012] Further, the numerical control system integrates the control of the Z-direction and Y-direction translation movements of the main shaft, the deflection direction, angle and angular velocity of the deflection box around the X-axis, the rotation direction and speed of the main shaft, the direction and speed of the stirrer, the vibration frequency and amplitude generated by the ultrasonic generator, and the operation parameters of the adjustable power DC power supply, the electromagnetic coil and the light source.

[0013] The application further discloses a multi-energy field coupling chemical mechanical polishing method for a large-volume aperture ratio thin-walled semi-closed complex structure part.

[0014] Step 1, pour the prepared chemical mechanical polishing liquid into the large-volume aperture ratio thin-walled semi-closed complex structure part and seal it, fix the sealed part on a clamp, and adjust the Z-direction and Y-direction of the main shaft to make the part enter the polishing cylinder through a control system;

[0015] Step 2, add the prepared chemical mechanical polishing liquid into the polishing cylinder, control the swing range, angular velocity and rotation speed of the part in the polishing liquid through a control system, and start the stirrer and the polishing liquid circulation system to stir the polishing liquid at a certain speed;

[0016] Step 3, set the vibration frequency and amplitude generated by the ultrasonic generator, the operation parameters of the adjustable power DC power supply, the electromagnetic coil and the light source according to the polishing requirements through a control system;

[0017] Step 4, after processing, turn off the stirrer, ultrasonic generator, DC power supply, light source and other equipment, raise the spindle position through the control system, take the part off the fixture, open the sealed port, pour out the polishing liquid in the cavity; the part must be cleaned several times in the ultrasonic cleaner with deionized water, and the inner cavity must also be cleaned several times by injecting deionized water through the water pump.

[0018] Further, the chemical mechanical polishing liquid comprises deionized water, abrasive particles, hydrogen peroxide, a pH adjuster and other auxiliary additives, the deionized water is pure and free of impurities, the abrasive particles are one or more of silicon oxide, aluminum oxide, cerium oxide, zirconium oxide, iron oxide, silicon carbide, cubic boron nitride, chromium oxide and nickel oxide, the average particle size is 0.8-3 mm, and the mass fraction in the polishing liquid is 15-25 wt%; the concentration of the hydrogen peroxide is 30%, and the content in the polishing liquid is 40-80 ml / L; the pH adjuster is one or more of tannic acid, malic acid, citric acid, metaphosphoric acid, triethanolamine and sodium carbonate, and the content in the polishing liquid is 40-100 g / L, and the pH value is adjusted to 11-13; the other auxiliary additives are one or more of chitosan oligosaccharide, sorbitol, sodium citrate and polyethylene glycol, and the mass fraction is 1-5 wt%. The additional magnetic abrasive particles include ferriferrous oxide, iron, nickel and iron-nickel alloy abrasive particles, the particle size is 0.1-0.05 mm, and the concentration is 0.1-5 wt%; the photosensitive component includes one or more of Prussian blue, titanium oxide, new indocyanine green, benzophenone, graphene oxide, graphene, 5-amino levulinic acid, tungsten nitride and methyl phenyl sulfide, and the concentration is 0.1-3 wt%; the total concentration of all abrasive particles does not exceed 20 wt%.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] 1. The present application proposes a new green and environmentally friendly chemical mechanical polishing method using one or more of ultrasonic, electromagnetic and light energy as auxiliary energy field, and realizes the cooperative polishing of the inner and outer surfaces of large-volume aperture ratio thin-walled semi-enclosed complex structure parts by using multi-energy field coupled chemical mechanical polishing.

[0021] 2. The polishing liquid of the present application flows in the inner cavity of the large-volume aperture ratio thin-walled semi-enclosed complex structure part after sealing, without dust pollution and liquid leakage, the polishing liquid mainly uses green and environmentally friendly components, and the used polishing liquid can be recycled after treatment.

[0022] 3. The present application solves the problem that the topologically optimized irregular surface parts are mainly removed by chemical dissolution, and the oxide film and passivation film are removed by small abrasive particles under the action of fluid pressure, so that there is no scratch on the surface of the part, and the possibility of cracks and fatigue sources generated by cyclic stress is excluded. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present application, and do not represent all the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting on the application or its applications or uses. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] Figure 1 A large-volume aperture ratio thin-walled semi-closed complex structure part real object diagram;

[0025] Figure 2 A three-dimensional assembly structure schematic diagram of a multi-energy field coupling chemical mechanical polishing equipment for a volume aperture ratio thin-walled semi-closed complex structure part;

[0026] Figure 3 A polishing cylinder, soft iron core and electromagnetic coil installation schematic diagram;

[0027] Figure 4 A stirrer structure schematic diagram;

[0028] Figure 5 A large-volume aperture ratio thin-walled semi-closed complex structure part surface roughness before and after chemical mechanical polishing.

[0029] In the figure: 1-bed; 2-Z direction moving guide rail; 3-Y direction moving guide rail; 4-deflection box; 5-numerical control system; 6-polishing cylinder; 7-soft iron core; 8-electromagnetic coil; 9-polishing cylinder support; 10-liquid outlet; 11-stirring motor; 12-liquid inlet; 13-stirrer. DETAILED DESCRIPTION

[0030] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all the embodiments. The following description of at least one exemplary embodiment is merely illustrative and in no way limits the application or its applications or uses. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] It is to be understood that the terms so far as the grammar used herein is concerned are to be interpreted in their dictionary meanings and should not be construed to open down the scope of the present application based on the usage as per se. It is also to be understood that the terminology and description used herein is only by way of explanation of the illustrative embodiments and should not be construed to limit the scope of the present application.

[0033] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the present application unless otherwise specifically stated. It is also to be understood that the drawings are not necessarily drawn to scale of the actual proportions of the various parts and components shown therein. Techniques, methods, and apparatus known to those of ordinary skill are not discussed in detail because such techniques, methods, and apparatus are considered to be part of the art. All examples shown and discussed herein are intended to be exemplary and non-limiting. Therefore, other examples of the illustrative embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the disclosure, and thus, once an item is defined in one figure, it is not necessary to discuss it further in connection with other figures.

[0034] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by terms such as "front", "back", "upper", "lower", "left", "right", "horizontal", "vertical", and "top", "bottom" are based on the orientation or positional relationships shown in the drawings, and are merely intended to facilitate the description and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the outline of the components themselves.

[0035] For the purposes of the description, reference can be made to spatially relative terms, such as "above", "below", "upper", "lower", and the like, to describe a device or feature's relationship to other devices or features as illustrated in the figures. It is to be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device is inverted in the figures, a device described as above other devices or structure would then be oriented below the other devices or structure. Thus, the exemplary term "above" can encompass both an orientation of above and below. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The terms "first", "second", and the like, as used herein do not have any specific meaning and are used only to distinguish one element from another. It is to be understood that the terms so used are interchangeable under appropriate circumstances.

[0036] In addition, it should be noted that the use of "first", "second", and the like, to describe a component does not limit the scope of the present application, unless otherwise stated, and the above terms are used only to distinguish one component from another.

[0037] The large-volume-to-aperture-ratio part to which the embodiment is directed is a topologically optimized support structure part commonly used in the fields of aerospace, military, and vehicles. The structural feature is that the outer shape is an irregular structure after mechanical calculation and topological optimization simulation, the inner cavity is filled with a lattice, and the lattice is also optimized and designed. The force-bearing positions are dense, the remaining positions are relatively sparse, and two holes with a diameter of 3-5 mm are left on the shell for cleaning the filling powder in the additive manufacturing process. The design significance of the large-volume-to-aperture-ratio part lies in reducing the weight of the part itself to the greatest extent while meeting the functional requirements of the force-bearing function, so as to reduce the operating cost of spacecraft such as rockets, spaceships, and satellites.

[0038] As shown in Figure 2 The embodiment of the present application discloses a multi-energy field coupling chemical mechanical polishing equipment for a large-volume-to-aperture-ratio thin-walled semi-enclosed complex structure part, which comprises a rack 1, a spindle system, a polishing cylinder, a multi-field triggering device, and a numerical control system installed in the rack 1. The equipment is a vertical structure and can realize chemical mechanical polishing of a large-volume-to-aperture-ratio thin-walled semi-enclosed complex structure part.

[0039] The inner and outer walls of the part to be polished need to be polished, and the workpiece is a semi-enclosed structure with only two openings, i.e., an inlet and an outlet, as shown in Figure 1 The large-volume-to-aperture-ratio thin-walled semi-enclosed complex structure part is a physical diagram applied to the field of aerospace and formed by selective laser melting of metal powder.

[0040] The spindle system is connected with a clamp for clamping the part to be polished, the spindle system is used to adjust the spatial position of the spindle so that the part to be polished enters the polishing cylinder and is immersed in the polishing liquid, the polishing cylinder is used to contain the chemical mechanical polishing liquid and the magnetic abrasive, the multi-field triggering device includes at least one of an ultrasonic generator, a magnetic field generating device and a light source, so that it has at least one of the auxiliary processing energy field of the ultrasonic field, the magnetic field and the light field, and the numerical control system is connected with the spindle system and the multi-field triggering device, and is used to control the parameters of the ultrasonic frequency, the amplitude and the magnetic field strength in the polishing process. Before processing, a predetermined amount of chemical mechanical polishing liquid and magnetic abrasive is added to the inlet of the part to be polished and kept in a sealed state during polishing. Specifically, for such a porous structure, it can be blocked to ensure that the polishing liquid does not be thrown out under the action of centrifugal force. In order to facilitate the additive powder to be cleaned out, the inlet and outlet are generally arranged at the bottom or top of the part, and the polishing liquid in the inside is in a full state.

[0041] The large-volume aperture ratio part to be polished, the outer surface is the main working surface, and the inner surface is not the main working surface, so that the adhered particles can be removed and metal particle peeling does not occur in space. Relatively speaking, the requirement for the smoothness of the inner surface is not as high as that of the outer surface, and the polishing precision that can be achieved is also not as high as that of the outer surface. In actual processing, the abrasive particles in the internal polishing liquid are hindered by the dot matrix support, and the linear velocity is lower than that of the external abrasive particles, so the removal effect on the defects of the inner surface is slightly worse than that of the outer surface. In this embodiment, in order to recycle the polishing liquid and keep the process as simple as possible, the polishing liquid compositions inside and outside are consistent and can be uniformly prepared. In other optional embodiments, because the inside cannot be illuminated, the photosensitive component does not play a role at this time, but the superimposed energy fields, ultrasonic and magnetic fields, still play a role. In view of this situation, the polishing liquid without the photosensitive component can be prepared.

[0042] As a preferred embodiment, it further includes a polishing liquid circulation system connected with the polishing cylinder, which is used to recover, filter and store the abrasive, and realize the recycling of the abrasive.

[0043] Specifically, the spindle system includes a Z-direction moving guide rail 2, a Y-direction moving guide rail 3, a deflection box 4 and a spindle, the Z-direction moving guide rail and the Y-direction moving guide rail are connected, and are used to provide the spindle with translational degrees of freedom in the Z-direction and the Y-direction; the deflection box is used to realize the swing of the spindle around the X-axis, and in this embodiment, the deflection box can realize the swing of the spindle around the X-axis within ±45°; the spindle is fixed on the deflection box to realize the rotational degrees of freedom of the Z-axis; the clamp is installed at the bottom of the spindle through a quick-change joint, and is used to fix the workpiece, and different clamps are used according to different parts. In this embodiment, the different parts refer to large-volume aperture ratio thin-walled semi-closed complex structure parts. In this embodiment, the deflection box is connected to the Z-direction moving guide rail and connected with the spindle, and can drive the spindle to swing.

[0044] In this embodiment, the multi-field triggering device is designed to include an ultrasonic generator, a magnetic field generating device, and a light source, so that it has auxiliary processing energy fields such as ultrasonic field, magnetic field, and light field, and realizes chemical mechanical polishing under different flow rates and auxiliary energy fields. Specifically, the ultrasonic generator is installed on the main shaft to provide Z-direction ultrasonic vibration for the main shaft.

[0045] The polishing cylinder 6 is a top-opened cylindrical structure made of non-magnetic corrosion-resistant material. The polishing cylinder is filled with chemical mechanical polishing liquid and magnetic abrasive during polishing. The bottom of the polishing cylinder is provided with a polishing cylinder support 9 and is installed on the bed. The polishing cylinder is provided with a liquid outlet 10 and a liquid inlet 12, which are connected with the polishing liquid circulation system respectively, for filtering and recycling the polishing liquid, realizing the recycling of the polishing liquid. The inside of the polishing cylinder is provided with a stirrer 13 for stirring the abrasive in the polishing cylinder to make the polishing liquid mixed relatively uniformly and avoid the deposition of abrasive particles at the bottom of the polishing cylinder. The stirrer 13 is driven by a stirring motor 11. In this embodiment, the stirrer 13 is arranged at the bottom of the polishing cylinder.

[0046] The magnetic field generating device includes a soft iron core 7, a plurality of multi-directionally wound electromagnetic coils 8, and an adjustable power DC power supply. Each electromagnetic coil is powered by the adjustable power DC power supply. The soft iron core is a top- and bottom-opened cylindrical thin-walled structure, which is detachably nested on the outer wall of the polishing cylinder and is made of soft iron material for enhancing the magnetic field generated by the electromagnetic coils. The soft iron core 7 can be installed or removed according to the processing needs. The electromagnetic coils are multi-group and have a differentiated installation mode. The electromagnetic coils installed in different directions are used to generate electromagnetic fields in different directions inside the polishing cylinder. Each direction of the electromagnetic coils is independently powered. Each electromagnetic coil in the same direction is also independently powered. During the polishing process, different voltages, currents, and directions of the DC power are controlled to generate electromagnetic fields with different intensities and directions in different areas inside the polishing cylinder, thereby controlling the magnetic field force to drive the magnetic abrasive to move inside the polishing cylinder. When all the electromagnetic coils 8 are powered off, the magnetic field inside the polishing cylinder 6 disappears, and the magnetic abrasive can be discharged through the liquid outlet 10.

[0047] Further, the light source is detachably installed on the bed and can be replaced with any one of a laser light source, an infrared light source, or an ultraviolet light source according to the processing needs. The light source is used to promote the chemical reaction between the chemical mechanical polishing liquid and the workpiece surface to generate an oxide film on the workpiece surface through photocatalysis to improve the chemical reaction activity.

[0048] Further, the numerical control system 5 integrates the control of the Z-direction and Y-direction translation movement of the main shaft, the deflection direction, angle, and angular velocity of the deflection box around the X-axis, the rotation direction and speed of the main shaft, the direction and speed of the stirrer, the vibration frequency and amplitude of the ultrasonic generator, and the operating parameters of the adjustable power DC power supply, the electromagnetic coils, and the light source.

[0049] The bed body is also equipped with a switch door, which is closed during operation, and the bed body and internal mechanism are coated with a hydrophobic, oleophobic and corrosion-resistant coating on the surface that can be splashed by the polishing liquid in the polishing cylinder.

[0050] The application also discloses a multi-energy field coupling chemical mechanical polishing method for a large-volume aperture ratio thin-wall semi-closed complex structure part.

[0051] Step 1, pour the prepared chemical mechanical polishing liquid into the large-volume aperture ratio thin-wall semi-closed complex structure part and seal it, fix the sealed part on a clamp, and adjust the Z direction and Y direction of the main shaft through a control system to make the part enter a polishing cylinder.

[0052] Step 2, add the prepared chemical mechanical polishing liquid into the polishing cylinder, control the swing range, angular velocity and rotational speed of the part in the polishing liquid through the control system, and start a stirrer and a polishing liquid circulating system to stir the polishing liquid at a certain speed; in the embodiment, the control system 5 controls the deflection box 4 and the main shaft to make the part swing in the polishing liquid at an angular velocity of 5 rpm in a range of ±45° and rotate at a speed of 70 rpm.

[0053] Step 3, set the vibration frequency and amplitude generated by an ultrasonic generator, the operating parameters of an adjustable power direct-current power supply, an electromagnetic coil and a light source according to the polishing requirements through the control system.

[0054] Step 4, after processing is completed, the stirrer, ultrasonic generator, direct-current power supply and light source are turned off, the position of the main shaft is raised through the control system, the part is taken off from the clamp, the sealing opening is opened, and the polishing liquid in the cavity is poured out; the part must be cleaned multiple times in a deionized water ultrasonic cleaner, and the inner cavity must also be cleaned multiple times by injecting deionized water through a water pump.

[0055] Further, the chemical mechanical polishing liquid comprises deionized water, abrasive particles, hydrogen peroxide, pH adjuster and other auxiliary additives, the deionized water is pure and free of impurities, the abrasive particles are one or more of silicon oxide, aluminum oxide, cerium oxide, zirconium oxide, iron oxide, silicon carbide, cubic boron nitride, chromium oxide, nickel oxide, the average particle size is 0.8-3mm, and the mass fraction in the polishing liquid is 15-25wt%; the concentration of the hydrogen peroxide is 30%, and the content in the polishing liquid is 40-80ml / L; the pH adjuster is one or more of tannic acid, malic acid, citric acid, metaphosphoric acid, triethanolamine, sodium carbonate, and the content in the polishing liquid is 40-100g / L, and the pH value is adjusted to 11-13; the other auxiliary additives are one or more of chitosan oligosaccharide, sorbitol, sodium citrate and polyethylene glycol, and the mass fraction is 1-5wt%. The additional magnetic abrasive particles include ferric oxide, iron, nickel, and iron-nickel alloy abrasive particles, the particle size is 0.1-0.05mm, and the concentration is 0.1-5wt%; the photosensitive component includes one or more of Prussian blue, titanium oxide, new indole cyanine green, benzophenone, graphene oxide, graphene, 5-amino levulinic acid, tungsten nitride and methyl phenyl sulfide, and the concentration is 0.1-3wt%; the total concentration of all abrasive particles does not exceed 20wt%.

[0056] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polishing method for a multi-energy field coupled chemical mechanical polishing (CMP) system for a large-volume, thin-walled, semi-enclosed complex structural part, characterized in that... The apparatus includes a frame, a spindle system, a polishing cylinder, a multi-field triggering device, and a CNC system. Both the inner and outer walls of the part to be polished need to be polished, and the workpiece has a semi-enclosed structure with only an inlet and an outlet. The spindle system is connected to a fixture for holding the workpiece. The spindle system is used to adjust the spatial position of the spindle so that the workpiece enters the polishing cylinder and is immersed in the polishing fluid. The multi-field triggering device includes an ultrasonic generator, a magnetic field generator, and a light source. The CNC system is connected to the spindle system and the multi-field triggering device to control the parameters of ultrasonic frequency, amplitude, and magnetic field strength during the spindle and polishing process. Before processing, a preset amount of chemical mechanical polishing fluid and magnetic abrasive are added to the inlet of the part to be polished and kept in a sealed state during the polishing process. The polishing cylinder is a cylindrical structure with an open top, made of non-magnetic and corrosion-resistant material. During polishing, it contains chemical mechanical polishing fluid and magnetic abrasive. The bottom of the polishing cylinder is equipped with polishing cylinder supports and is mounted on the bed. It has an outlet and an inlet, which are connected to the polishing fluid circulation system. It is equipped with a stirrer inside to agitate the abrasive inside the polishing cylinder, so that the polishing liquid is mixed relatively evenly and the abrasive particles are prevented from depositing at the bottom of the polishing cylinder; The polishing fluid circulation system is connected to the polishing cylinder and is used to recover, filter, and store abrasive materials, thereby realizing the recycling of abrasive materials. The magnetic field generating device includes a soft iron core, multiple electromagnetic coils wound in multiple directions, and an adjustable power DC power supply. Each electromagnetic coil is powered by the adjustable power DC power supply. The soft iron core is a thin-walled cylindrical structure with an open top and bottom, which is detachably nested in the outer wall of the polishing cylinder to enhance the magnetic field generated by the electromagnetic coils. The electromagnetic coils are in multiple groups and have different installation methods. Electromagnetic coils installed in different directions are used to generate electromagnetic fields in different directions inside the polishing cylinder. The electromagnetic coils in each direction are powered independently, and the electromagnetic coils in the same direction are also powered independently. During the polishing process, by controlling the DC power of different voltages, different currents, and different directions, electromagnetic fields of different intensities and different directions are generated in different areas inside the polishing cylinder, thereby controlling the magnetic force to drive the magnetic abrasive to move inside the polishing cylinder. The light source is detachably mounted on the machine bed and can be replaced with any one of laser light source, infrared light source or ultraviolet light source according to processing requirements. The light source is used to promote the chemical reaction between the chemical mechanical polishing fluid and the workpiece surface, so that an oxide film is generated on the workpiece surface. The specific steps are as follows: Step 1: Pour the prepared chemical mechanical polishing slurry into the interior of the large-volume, thin-walled, semi-enclosed complex structure part with a large aperture ratio and seal it. Fix the sealed part on the fixture and adjust the Z and Y directions of the spindle through the control system to put the part into the polishing cylinder. Step 2: Add the prepared chemical mechanical polishing slurry to the polishing cylinder. Control the oscillation range, angular velocity and rotation speed of the parts in the polishing slurry through the control system. At the same time, turn on the agitator and polishing slurry circulation system to make the polishing slurry stir at a certain speed. Step 3: Set the vibration frequency and amplitude of the ultrasonic generator according to the polishing requirements through the control system, and adjust the operating parameters of the adjustable DC power supply, electromagnetic coil and light source. Step 4: After processing, turn off the agitator, ultrasonic generator, adjustable power DC power supply, and light source. Raise the spindle position through the control system, remove the part from the fixture, open the sealing port, and pour out the polishing liquid in the cavity. The part needs to be cleaned multiple times with deionized water in the ultrasonic cleaning machine, and the inner cavity also needs to be cleaned multiple times with deionized water injected by the water pump.

2. The method according to claim 1, characterized in that, The chemical mechanical polishing slurry comprises deionized water, abrasive grains, hydrogen peroxide, a pH adjuster, and other auxiliary additives. The deionized water is pure and free of impurities. The abrasive grains are one or more selected from silicon oxide, aluminum oxide, cerium oxide, zirconium oxide, iron oxide, silicon carbide, cubic boron nitride, chromium oxide, and nickel oxide, with an average particle size of 0.8–3 mm, and a mass fraction of 15–25 wt% in the polishing slurry. The hydrogen peroxide concentration is 30%, and its content in the polishing slurry is 40–80 ml / L. The pH adjuster is one or more selected from tannic acid, malic acid, citric acid, metaphosphoric acid, triethanolamine, and sodium carbonate, with a content of 40–100 g / L in the polishing slurry, adjusting the pH value to 11–13. The other auxiliary additives are one or more selected from chitosan oligosaccharide, sorbitol, sodium citrate, and polyethylene glycol, with a mass fraction of 1–5 wt%. Additional magnetic abrasive grains include iron(III) oxide, iron, nickel, and iron-nickel alloy abrasive grains, with a particle size of 0.1–0.05 mm. mm, concentration of 0.1~5wt%; photosensitizing components include Prussian blue, titanium dioxide, neoindocyanine green, benzophenone, graphene oxide, graphene, 5 One or more of aminolevulinic acid, tungsten nitride, and methyl phenyl sulfide are used, with a concentration of 0.1 to 3 wt%; the total concentration of all abrasive particles does not exceed 20 wt%.

3. The method according to claim 1, characterized in that, The spindle system includes a Z-direction moving guide rail, a Y-direction moving guide rail, a deflection box, and a spindle. The Z-direction moving guide rail and the Y-direction moving guide rail are connected to provide the spindle with translational degrees of freedom in the Z and Y directions. The deflection box is used to realize the spindle's oscillation around the X-axis. The spindle is fixed on the deflection box to realize the rotational degree of freedom in the Z-axis. The fixture is installed at the bottom of the spindle through a quick-change joint to fix the workpiece. Different fixtures are replaced according to different parts.

4. The method according to claim 1, characterized in that, The ultrasonic generator is mounted on the spindle and is used to provide ultrasonic vibration in the Z direction to the spindle.

5. The method according to claim 3, characterized in that, The CNC system integrates control over the Z and Y direction translational motion of the spindle, the deflection direction, angle, and angular velocity of the deflection box around the X-axis, the rotation direction and speed of the spindle, the direction and speed of the stirrer, the vibration frequency and amplitude generated by the ultrasonic generator, and the operating parameters of the adjustable power DC power supply, electromagnetic coil, and light source.

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