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

Abstract

The invention relates to multi-energy-field coupling chemical mechanical polishing equipment and method for a large-volume-aperture-ratio thin-wall semi-closed complex-structure part. Comprising a rack, a main shaft system, a polishing barrel, a multi-field triggering device and a numerical control system, the main shaft system is connected with a clamp used for clamping a to-be-polished piece, the main shaft system is used for adjusting the spatial position of a main shaft, so that the to-be-polished piece enters the polishing barrel and is immersed in polishing liquid, and the polishing barrel is used for containing chemical mechanical polishing liquid and magnetic grinding materials; the multi-field triggering device comprises at least one of an ultrasonic generator, a magnetic field generating device and a light source, and before machining, a preset amount of chemical mechanical polishing liquid and magnetic grinding materials are added into an inlet of the to-be-polished part, and the sealing state is kept in the polishing process. According to the method, chemical dissolution removal is taken as a main part, removal of an oxidation film and a passivation film by tiny abrasive particles under the action of fluid pressure is taken as an auxiliary part, the surface of a part is free of scratches, and the possibility that cracks and fatigue sources are generated by cyclic stress is eliminated.

Description

Technical Field

[0001] The present invention relates to the field of mechanical processing and manufacturing technology, and in particular to a multi-energy field coupled chemical mechanical polishing equipment and method for thin-walled semi-closed complex structure parts with large volume-to-aperture ratio. Background Art

[0002] Large volume aperture ratio thin-walled semi-enclosed complex structure parts usually have defects such as excessive weight, rough surface, and poor mechanical properties. However, as important parts in aerospace equipment, they have high requirements for dimensional accuracy, surface quality, and assembly accuracy. Due to the complex structure of the semi-enclosed inner wall of large volume aperture ratio thin-walled parts, the wall thickness is very small, and only the inlet and outlet are open, so traditional manual grinding and polishing, soft sand belt polishing, robot polishing, and airbag polishing methods cannot be used. At present, the inner surface of large volume aperture ratio thin-walled semi-enclosed complex structure parts at home and abroad usually adopts chemical polishing, electrochemical polishing, abrasive flow polishing, and blowing high-pressure airflow to remove defects such as powder adhesion on the inner surface of the parts. However, chemical polishing will lose the prototype size of the parts, electrolytic polishing is difficult to obtain a smooth surface on the inner surface with large roughness, and the thin-walled structure is easily deformed during abrasive flow polishing; high-pressure airflow cannot completely remove the defects on the inner surface of the parts, and the inner surface is rough and the surface quality is poor. For magnetorheological polishing, the complex lattice structure inside thin-walled parts with large volume aperture ratios hinders the flow of magnetic abrasives, and the non-uniform flow field acting on the inner wall of thin-walled parts will also change their shape and position accuracy, making it difficult to avoid over-polishing / under-polishing. The current polishing technology is difficult / impossible to quickly and non-destructively polish the semi-enclosed inner wall of thin-walled parts with large volume aperture ratios, which greatly affects the polishing efficiency and quality. Summary of the invention

[0003] In response to the technical problems raised above, a multi-energy field coupled chemical mechanical polishing equipment and method for thin-walled semi-closed complex structure parts with a large volume aperture ratio is provided, and composite energy field-assisted chemical mechanical polishing is used to achieve surface treatment of semi-closed complex structure parts with a large volume aperture ratio.

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

[0005] A multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-closed complex structure parts with large volume aperture ratio, comprising a frame, a spindle system, a polishing cylinder, a multi-field trigger device and a numerical control system. The inner and outer walls of the parts to be polished need to be polished, and the workpiece is a semi-closed structure with only an inlet and an outlet open. The spindle system is connected to a fixture for clamping the parts to be polished. The spindle system is used to adjust the spatial position of the spindle so that the parts to be polished enter the polishing cylinder and are immersed in the polishing liquid. The polishing cylinder is used to contain chemical mechanical polishing liquid and magnetic abrasives. The multi-field trigger device includes at least one of an ultrasonic generator, a magnetic field generator, and a light source, so that it has at least one auxiliary processing energy field of ultrasonic field, magnetic field, and light field. The numerical control system is connected to the spindle system and the multi-field trigger device, and is used 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 liquid and magnetic abrasive are added to the inlet of the parts to be polished and kept sealed during the polishing process.

[0006] Furthermore, it also includes a polishing liquid circulation system, which is connected to the polishing cylinder and is used to recover, filter and store abrasives to achieve the recycling of abrasives.

[0007] Furthermore, the spindle system includes a Z-direction movable guide rail, a Y-direction movable guide rail, a deflection box and a spindle. The Z-direction movable guide rail and the Y-direction movable guide rail are connected to provide the spindle with translational freedom in the Z and Y directions; the deflection box is used to realize the swing of the spindle around the X-axis; the spindle is fixed on the deflection box to realize the rotational freedom of the Z-axis; the fixture is installed at the bottom of the spindle through a quick-change joint to fix the workpiece, and different fixtures are replaced according to different parts.

[0008] Furthermore, the ultrasonic generator is installed on the main shaft and is used to provide the main shaft with ultrasonic vibration in the Z direction.

[0009] Furthermore, the polishing cylinder is a cylindrical structure with an open top, and is made of non-magnetic corrosion-resistant material. During polishing, it contains chemical mechanical polishing liquid and magnetic abrasives. Polishing cylinder supports are provided around the bottom of the polishing cylinder and are installed on the bed; a liquid outlet and a liquid inlet are provided on it, which are respectively connected to the polishing liquid circulation system; an agitator is provided inside it for stirring the abrasive in the polishing cylinder so that the polishing liquid is mixed relatively evenly to avoid the abrasive particles from being deposited at the bottom of the polishing cylinder.

[0010] Furthermore, the magnetic field generating device includes 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, which can be detachably nested in the outer wall of the polishing tube to enhance the magnetic field generated by the electromagnetic coil. The electromagnetic coils are in multiple groups and have differentiated installation methods. The electromagnetic coils installed in different directions are used to generate electromagnetic fields in different directions inside the polishing tube. The electromagnetic coils in each direction are powered independently of each other, and the electromagnetic coils in the same direction are also powered independently. During the polishing process, electromagnetic fields of different intensities and directions are generated in different areas inside the polishing tube by controlling direct currents of different voltages, currents and directions, thereby controlling the magnetic field force to drive the magnetic abrasive to move inside the polishing tube.

[0011] Furthermore, the light source is detachably mounted 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 processing requirements. The light source is used to promote a chemical reaction between the chemical mechanical polishing liquid and the workpiece surface, so that an oxide film is generated on the workpiece surface.

[0012] Furthermore, the CNC system integrates and controls the Z-direction 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 agitator, the vibration frequency and amplitude generated by the ultrasonic generator, and the operating parameters of the adjustable power DC power supply, the electromagnetic coil and the light source.

[0013] The present invention also discloses a multi-energy field coupled chemical mechanical polishing method for thin-walled semi-enclosed complex structure parts with large volume aperture ratio, and the specific steps are as follows:

[0014] Step 1, pour the prepared chemical mechanical polishing liquid into the interior of the thin-walled semi-enclosed complex structure parts with large volume aperture ratio and seal them, fix the sealed parts on the fixture, and adjust the Z and Y directions of the main axis through the control system to place the parts into the polishing cylinder;

[0015] Step 2, adding the prepared chemical mechanical polishing liquid into the polishing cylinder, controlling the swing range, angular velocity and rotation speed of the parts in the polishing liquid through the control system, and simultaneously starting the agitator and the polishing liquid circulation system to stir the polishing liquid at a certain speed;

[0016] Step 3: Setting 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 according to the polishing requirements through the control system;

[0017] Step 4. After processing is completed, turn off the agitator, ultrasonic generator, DC power supply, light source and other equipment, raise the spindle position through the control system, remove the parts from the fixture, open the seal, and pour out the polishing liquid in the cavity; the parts must be cleaned multiple times with deionized water in an ultrasonic cleaner, and the inner cavity must also be cleaned multiple times by injecting deionized water through a water pump.

[0018] Furthermore, the chemical mechanical polishing liquid includes deionized water, abrasives, hydrogen peroxide, a pH regulator and other auxiliary additives, the deionized water is pure and free of impurities, the abrasives 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, with an average particle size of 0.8 to 3 mm, and a mass fraction of 15 to 25 wt% in the polishing liquid; the concentration of hydrogen peroxide is 30%, and the content in the polishing liquid is 40 to 80 ml / L; the pH regulator 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 to 100 g / L, and the pH value is adjusted to 11 to 13; the other auxiliary additives are one or more of chitosan oligosaccharides, sorbitol, sodium citrate, and polyethylene glycol, with a mass fraction of 1 to 5 wt%. The additional magnetic abrasives include ferroferric oxide, iron, nickel, and iron-nickel alloy abrasives with a particle size of 0.1 to 0.05 mm and a concentration of 0.1 to 5 wt %; the photosensitive components include one or more of Prussian blue, titanium oxide, new indocyanine green, benzophenone, graphene oxide, graphene, 5-aminolevulinic acid, tungsten nitride, and methyl phenyl sulfide with a concentration of 0.1 to 3 wt %; the total concentration of all abrasives does not exceed 20 wt %.

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

[0020] 1. The present invention proposes a new green and environmentally friendly chemical mechanical polishing method using one or more of ultrasound, electromagnetic and light energy as auxiliary energy fields, and adopts multi-energy field coupled chemical mechanical polishing to achieve coordinated polishing of the inner and outer surfaces of thin-walled semi-enclosed complex structure parts with large volume aperture ratio;

[0021] 2. The polishing liquid of the present invention flows in the inner cavity of the thin-walled semi-enclosed complex structure parts with large volume aperture ratio after sealing, without dust pollution and liquid leakage. The polishing liquid mostly adopts green and environmentally friendly ingredients, and the used polishing liquid can be recycled after treatment;

[0022] 3. The present invention solves the problem of topological optimization of irregular surface parts mainly by chemical dissolution removal, supplemented by the removal of oxide film and passivation film by tiny abrasive particles under the action of fluid pressure. There are no scratches on the surface of the parts, eliminating the possibility of cracks and fatigue sources caused by cyclic stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 This is a physical picture of a thin-walled, semi-enclosed, complex structure part with a large volume-to-aperture ratio;

[0025] Figure 2 A schematic diagram of the three-dimensional assembly structure of multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with high volume-to-aperture ratio;

[0026] Figure 3 This is a schematic diagram of the installation of the polishing cylinder, soft iron core and electromagnetic coil;

[0027] Figure 4 is a schematic diagram of the agitator structure;

[0028] Figure 5 Comparison of surface roughness before and after chemical mechanical polishing of thin-walled semi-closed complex structure parts with large volume-to-aperture ratio.

[0029] In the figure: 1-bed; 2-Z direction moving guide rail; 3-Y direction moving guide rail; 4-deflection box; 5-CNC 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, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0034] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0035] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0036] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0037] The large volume aperture ratio parts targeted by this embodiment are topological optimization support structure parts commonly used in the fields of aerospace, military and vehicles. Their structural characteristics are that their appearance is an irregular structure after mechanical calculation and topological optimization simulation, and the inner cavity is filled with a lattice. In addition, the lattice is also optimized and designed, with dense load-bearing positions and relatively loose positions at other positions. Two holes with a diameter of 3 to 5 mm are left on the shell to clean the filling powder during the additive manufacturing process. The design significance of large volume aperture ratio parts is to reduce the weight of the parts themselves to the greatest extent while meeting their load-bearing functional requirements, so as to reduce the operating costs of spacecraft such as rockets, spacecrafts, and satellites.

[0038] like Figure 2 As shown, an embodiment of the present invention discloses a multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-closed complex structure parts with a large volume aperture ratio, including a frame 1 and a spindle system, a polishing cylinder, a multi-field trigger device and a numerical control system installed in the frame 1. The equipment is a vertical structure and can realize chemical mechanical polishing of thin-walled semi-closed complex structure parts with a large volume aperture ratio.

[0039] The inner and outer walls of the parts to be polished need to be polished, and the workpiece is a semi-closed structure with only the inlet and outlet open. Figure 1 As shown, it is a physical picture of a thin-walled semi-closed complex structure part with a large volume-to-aperture ratio, which is used in the aerospace field and is formed by selective laser melting of metal powder.

[0040] The spindle system is connected to a fixture for clamping the workpiece to be polished. The spindle system is used to adjust the spatial position of the spindle so that the workpiece to be polished enters the polishing cylinder and is immersed in the polishing liquid. The polishing cylinder is used to contain chemical mechanical polishing liquid and magnetic abrasive. The multi-field trigger 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 auxiliary processing energy field of an ultrasonic field, a magnetic field, and a light field. The numerical control system is connected to the spindle system and the multi-field trigger device, and is used 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 liquid and magnetic abrasive are added to the inlet of the part to be polished and kept sealed during the polishing process. Specifically, for this porous structure, it can be blocked to ensure that the polishing liquid will not be thrown out under the action of centrifugal force during the polishing process. In order to facilitate the cleaning of the additive powder, the inlet and outlet are generally set at the bottom or top of the part, and the internal polishing liquid is filled.

[0041] For parts with large volume aperture ratio to be polished, the outer surface is the main working surface, and the inner surface is not the main working surface, so as to be able to remove adhered particles and prevent metal particles from peeling off in space. Relatively speaking, the finish requirement of the inner surface is not as high as that of the outer surface, and the polishing accuracy that can be achieved is not as high as that of the outer surface. In the actual processing process, the abrasive particles in the internal polishing liquid are hindered by the lattice support, and the linear speed is lower than that of the external abrasive particles, and the effect of removing defects on the inner surface is slightly worse than that on the outer surface. In this embodiment, in order to recycle the polishing liquid and simplify the process as much as possible, the components of the internal and external polishing liquids are consistent and uniformly formulated. In other optional embodiments, because the interior is not illuminated by light, the photosensitive component does not play a role at this time, but the superimposed energy field, ultrasound and magnetic field still play a role. In view of this situation, a polishing liquid without a photosensitive component can be prepared.

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

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

[0044] In this embodiment, the multi-field trigger 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 the main shaft with ultrasonic vibration in the Z direction.

[0045] The polishing cylinder 6 is a cylindrical structure with an open top, made of non-magnetic corrosion-resistant material. During polishing, the polishing cylinder contains chemical mechanical polishing liquid and magnetic abrasives. The bottom of the polishing cylinder is surrounded by polishing cylinder supports 9 and is installed on the bed. It is provided with a liquid outlet 10 and a liquid inlet 12, which are respectively connected to the polishing liquid circulation system for filtering and recycling the polishing liquid to achieve the recycling of the polishing liquid. A stirrer 13 is provided inside the polishing cylinder to stir the abrasive in the polishing cylinder so that the polishing liquid is mixed relatively evenly to avoid the abrasive particles from being deposited at the bottom of the polishing cylinder. The stirring motor 11 provides power for the stirrer 13. 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 electromagnetic coils 8 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, which is detachably nested in the outer wall of the polishing tube. The material is soft iron material, which is used to enhance the magnetic field generated by the electromagnetic coil. The soft iron core 7 can be installed or removed according to processing needs. The electromagnetic coils are multiple groups and present differentiated installation methods. The electromagnetic coils installed in different directions are used to generate electromagnetic fields in different directions inside the polishing tube. The electromagnetic coils in each direction are independently powered, and the electromagnetic coils in the same direction are also independently powered. During the polishing process, different voltages, different currents, and different directions of direct current are controlled to generate electromagnetic fields of different strengths and directions in different areas inside the polishing tube, thereby controlling the magnetic field force to drive the magnetic abrasive to move inside the polishing tube. When all electromagnetic coils 8 are powered off, the magnetic field inside the polishing tube 6 disappears, and the magnetic abrasive can be discharged through the liquid outlet 10.

[0047] Furthermore, the light source is detachably mounted 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 processing requirements. The chemical reaction activity is increased through photocatalysis. The light source is used to promote the chemical reaction between the chemical mechanical polishing liquid and the workpiece surface, so that an oxide film is generated on the workpiece surface.

[0048] Furthermore, the numerical control system 5 integrates and controls the Z-direction 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 agitator, the vibration frequency and amplitude generated by the ultrasonic generator, and the operating parameters of the adjustable power DC power supply, the electromagnetic coil and the light source.

[0049] The bed is also equipped with a switch door, which is closed during operation. The surfaces of the bed and internal mechanisms that can be splashed by the polishing liquid in the polishing cylinder are coated with hydrophobic, oleophobic and anti-corrosion coatings.

[0050] The present invention also discloses a multi-energy field coupled chemical mechanical polishing method for thin-walled semi-enclosed complex structure parts with large volume aperture ratio, and the specific steps are as follows:

[0051] Step 1, pour the prepared chemical mechanical polishing liquid into the interior of the thin-walled semi-enclosed complex structure parts with large volume aperture ratio and seal them, fix the sealed parts on the fixture, and adjust the Z and Y directions of the main axis through the control system to place the parts into the polishing cylinder;

[0052] Step 2: Add the prepared chemical mechanical polishing liquid into the polishing cylinder, control the swing range, angular velocity and rotation speed of the parts in the polishing liquid through the control system, and start the agitator and the polishing liquid circulation system at the same time to stir the polishing liquid at a certain speed; in this embodiment, the control system 5 controls the deflection box 4 and the main shaft to make the parts swing in the polishing liquid at an angular velocity of 5rpm within the range of ±45° and rotate at a speed of 70rpm.

[0053] Step 3: Setting 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 according to the polishing requirements through the control system;

[0054] Step 4. After processing is completed, turn off the agitator, ultrasonic generator, DC power supply, light source and other equipment, raise the spindle position through the control system, remove the parts from the fixture, open the seal, and pour out the polishing liquid in the cavity; the parts must be cleaned multiple times with deionized water in an ultrasonic cleaner, and the inner cavity must also be cleaned multiple times by injecting deionized water through a water pump.

[0055] Furthermore, the chemical mechanical polishing liquid includes deionized water, abrasives, hydrogen peroxide, a pH regulator and other auxiliary additives, the deionized water is pure and free of impurities, the abrasives 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, with an average particle size of 0.8 to 3 mm, and a mass fraction of 15 to 25 wt% in the polishing liquid; the concentration of hydrogen peroxide is 30%, and the content in the polishing liquid is 40 to 80 ml / L; the pH regulator 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 to 100 g / L, and the pH value is adjusted to 11 to 13; the other auxiliary additives are one or more of chitosan oligosaccharides, sorbitol, sodium citrate, and polyethylene glycol, with a mass fraction of 1 to 5 wt%. The additional magnetic abrasives include ferroferric oxide, iron, nickel, and iron-nickel alloy abrasives with a particle size of 0.1 to 0.05 mm and a concentration of 0.1 to 5 wt %; the photosensitive components include one or more of Prussian blue, titanium oxide, new indocyanine green, benzophenone, graphene oxide, graphene, 5-aminolevulinic acid, tungsten nitride, and methyl phenyl sulfide with a concentration of 0.1 to 3 wt %; the total concentration of all abrasives does not exceed 20 wt %.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio, characterized in that: It includes a frame, a spindle system, a polishing cylinder, a multi-field trigger device and a numerical control system. The inner and outer walls of the part to be polished need to be polished, and the workpiece is a semi-closed structure with only an entrance and an exit open. The spindle system is connected to a fixture 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 chemical mechanical polishing liquid and magnetic abrasives. The multi-field trigger 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 auxiliary processing energy field of an ultrasonic field, a magnetic field, and a light field. The numerical control system is connected to the spindle system and the multi-field trigger device, and is used 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 liquid and magnetic abrasive are added to the entrance of the part to be polished and kept sealed during the polishing process.

2. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1 is characterized in that: It also includes a polishing liquid circulation system, which is connected to the polishing cylinder and is used to recover, filter and store abrasives to achieve the recycling of abrasives.

3. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1 is characterized in that: The spindle system includes a Z-direction movable guide rail, a Y-direction movable guide rail, a deflection box and a spindle. The Z-direction movable guide rail and the Y-direction movable guide rail are connected to provide the spindle with translational freedom in the Z and Y directions; the deflection box is used to realize the swing of the spindle around the X-axis; the spindle is fixed on the deflection box to realize the rotational freedom of the Z-axis; the fixture is installed at the bottom of the spindle through a quick-change joint to fix the workpiece, and different fixtures are replaced according to different parts.

4. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1 is characterized in that: The ultrasonic generator is installed on the main shaft and is used to provide the main shaft with ultrasonic vibration in the Z direction.

5. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1, characterized in that: The polishing cylinder is a cylindrical structure with an open top, made of non-magnetic corrosion-resistant material, and contains chemical mechanical polishing liquid and magnetic abrasives during polishing. Polishing cylinder supports are arranged around the bottom of the polishing cylinder and are installed on the bed; a liquid outlet and a liquid inlet are arranged on the polishing cylinder, which are respectively connected to the polishing liquid circulation system; An agitator is provided inside the polishing cylinder to stir the abrasive in the polishing cylinder so that the polishing liquid is mixed relatively evenly and prevent the abrasive particles from depositing at the bottom of the polishing cylinder.

6. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1, characterized in that: The magnetic field generating device includes 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, which can be detachably nested in the outer wall of the polishing tube to enhance the magnetic field generated by the electromagnetic coil. The electromagnetic coils are in multiple groups and have differentiated installation methods. The electromagnetic coils installed in different directions are used to generate electromagnetic fields in different directions inside the polishing tube. The electromagnetic coils in each direction are powered independently of each other, and the electromagnetic coils in the same direction are also powered independently. During the polishing process, electromagnetic fields of different intensities and directions are generated in different areas inside the polishing tube by controlling direct current of different voltages, currents, and directions, thereby controlling the magnetic field force to drive the magnetic abrasive to move inside the polishing tube.

7. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1, characterized in that: The light source is detachably mounted 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 processing requirements. The light source is used to promote a chemical reaction between the chemical mechanical polishing liquid and the workpiece surface, so that an oxide film is generated on the workpiece surface.

8. The multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to claim 1, characterized in that: The numerical control system integrates and controls the Z-direction 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, the electromagnetic coil and the light source.

9. A polishing method based on the multi-energy field coupled chemical mechanical polishing equipment for thin-walled semi-enclosed complex structure parts with large volume aperture ratio according to any one of claims 1 to 8, characterized in that: The specific steps are as follows: Step 1, pour the prepared chemical mechanical polishing liquid into the interior of the thin-walled semi-enclosed complex structure parts with large volume aperture ratio and seal them, fix the sealed parts on the fixture, and adjust the Z and Y directions of the main axis through the control system to place the parts into the polishing cylinder; Step 2, adding the prepared chemical mechanical polishing liquid into the polishing cylinder, controlling the swing range, angular velocity and rotation speed of the parts in the polishing liquid through the control system, and simultaneously starting the agitator and the polishing liquid circulation system to stir the polishing liquid at a certain speed; Step 3: Setting 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 according to the polishing requirements through the control system; Step 4. After processing is completed, turn off the agitator, ultrasonic generator, DC power supply, light source and other equipment, raise the spindle position through the control system, remove the parts from the fixture, open the seal, and pour out the polishing liquid in the cavity; the parts must be cleaned multiple times with deionized water in an ultrasonic cleaner, and the inner cavity must also be cleaned multiple times by injecting deionized water through a water pump.

10. The method according to claim 9, characterized in that The chemical mechanical polishing liquid comprises deionized water, abrasive grains, hydrogen peroxide, a pH regulator and other auxiliary additives. The deionized water is pure and free of impurities. The abrasive grains 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, with an average particle size of 0.8 to 3 mm and a mass fraction of 15 to 25 wt % in the polishing liquid. The concentration of hydrogen peroxide is 30%, and the content of hydrogen peroxide in the polishing liquid is 40 to 80 ml / L. The pH regulator is one or more of tannic acid, malic acid, citric acid, metaphosphoric acid, triethanolamine and sodium carbonate, and the content of hydrogen peroxide in the polishing liquid is 15 to 25 wt %. The amount is 40-100 g / L, and the pH value is adjusted to 11-13; the other auxiliary additives are one or more of chitosan oligosaccharides, sorbitol, sodium citrate, and polyethylene glycol, with a mass fraction of 1-5wt%, and the additional magnetic abrasives include ferroferric oxide, iron, nickel, and iron-nickel alloy abrasives with a particle size of 0.1-0.05 mm and a concentration of 0.1-5wt%; the photosensitive components include Prussian blue, titanium oxide, new indocyanine green, benzophenone, graphene oxide, graphene, 5-aminolevulinic acid, tungsten nitride, and methyl phenyl sulfide. One or more of the concentration is 0.1-3wt%; the total concentration of all abrasives does not exceed 20wt%.

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