Chemical enhancement magnetic shear thickening medium flow polishing method for complex inner surface

Abstract

The invention discloses a chemical enhancement magnetic shear thickening medium flow polishing method for a complex inner surface, and belongs to the technical field of magnetic field auxiliary polishing. In order to solve the problems of low polishing efficiency, difficulty in precise regulation and poor removal uniformity of traditional abrasive flow polishing, a chemical enhanced magnetic shear thickening polishing medium is developed, an inner surface channel and a polishing system form a flow channel, and magnetic poles with different distribution and quantity are configured in a machining area; after a magnetic field is applied, a flexible composite particle cluster is formed in the polishing medium of the flow channel; under the action of a flow field, flexible reinforced composite particle clusters containing different contents of chemical oxidizing agents are formed, and micro-convex peaks on the inner surface are oxidized to different degrees; a soft passivation layer generated by oxidation and abrasive particles in the flexible reinforced composite particle cluster generate a cutting effect and are removed; and the original surface is exposed to the polishing medium again, the process is repeated, and efficient and high-quality polishing of the workpiece is achieved. The method can be applied to polishing of complex inner surfaces such as conformal cooling channels.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of magnetic field assisted polishing, and particularly relates to a complex inner surface chemical enhancement magnetic shear thickening medium flow polishing method. BACKGROUND

[0002] The conformal cooling channel, hydraulic valve body, fuel nozzle and the like are typical complex inner surface parts, which are usually integrated with multiple functions such as cooling, lubrication and heat exchange, and are widely used in the fields of aerospace, national defense and military industry, and are indispensable components of modern high-end equipment. However, the internal structure of these parts is complex, and the material performance, size precision and surface quality have very high requirements. The current abrasive flow polishing technology does not need special tools or complex fixtures, has excellent spatial accessibility and sub-micron material removal capacity, and has been widely used in the field of precision and ultra-precision machining, especially for polishing treatment of complex surfaces and high-precision parts. However, the traditional abrasive flow polishing technology still faces key common problems such as low polishing efficiency, difficult precision control, poor material removal uniformity and the like when processing complex inner surface workpieces. The chemical polishing technology is widely used due to its high polishing efficiency, and the magnetic shear thickening polishing technology has a broad application prospect due to its strong controllability, large abrasive holding force and good material removal uniformity. Therefore, in order to overcome the above-mentioned problems in the polishing process of complex inner surface, it is of important theoretical significance and practical application value to develop a new type of complex inner surface chemical enhancement magnetic shear thickening medium flow polishing method.

[0003] In the field of existing magnetic field assisted polishing technology, an invention patent with patent application number CN202411677822.3 discloses a solid-liquid two-phase flow magnetic shear thickening polishing device and method based on controllable multi-physical field coupling. The method controls the solidification degree of the polishing medium and the control force of the abrasive by precisely regulating the coupling effect of the magnetic field and the flow field, realizes efficient and high-quality precise polishing of the workpiece, but has certain spatial limitations and low processing efficiency for complex inner surfaces. An invention patent with patent application number CN202410913339.4 discloses a multiple flexible magnetic shear thickening polishing method. The method realizes flexible control of the abrasive force on the surface of the workpiece by using magnetic shear thickening medium and flexible material elastic layer. The method mainly removes materials through mechanical behavior. An invention patent with patent application number CN202310347178.2 discloses a magnetic guidance release magnetic shear thickening chemical polishing method. The method uses magnetic field to guide the movement of the magnetic package to the processing area to release chemicals, realizes localized erosion and processing, but the method cannot adapt to inner surfaces with different curvatures. Compared with the existing patent technology, the present application develops a new type of chemical enhanced magnetic shear thickening polishing medium, ensures precise regulation of the magnetic field and flow field during polishing, realizes chemical and mechanical synergistic effect, significantly improves polishing efficiency and uniformity of material removal, and has essential difference from the existing magnetic field assisted polishing method. SUMMARY

[0004] The present application proposes a complex inner surface chemical enhanced magnetic shear thickening medium flow polishing method to solve the key common problems of low polishing efficiency, precise regulation difficulty and poor material removal uniformity in the current abrasive flow polishing technology. The chemical enhanced magnetic shear thickening polishing medium is developed, the inner surface channel and the polishing system form a flow channel, and different distribution and number of magnetic poles are configured in the processing area. After applying the magnetic field, "flexible composite particle clusters" are formed in the polishing medium of the flow channel. Under the action of the flow field, "flexible enhanced composite particle clusters" containing different contents of chemical oxidants are formed, which erode the micro-peaks of the inner surface to different degrees. The soft passivation layer generated after erosion is removed by cutting action with abrasive particles in the "flexible enhanced composite particle clusters". The original surface is exposed to the polishing medium again, and the above process is repeated to realize efficient and high-quality polishing of the workpiece. The present application ensures precise regulation of the magnetic field and flow field during polishing, realizes chemical and mechanical synergistic effect, significantly improves polishing efficiency and uniformity of surface material removal, and is an important breakthrough for efficient and high-quality polishing of complex inner surface parts.

[0005] The complex inner surface chemical enhancement magnetic shear thickening medium flow polishing method of the application adopts a new type of chemical enhancement magnetic shear thickening polishing medium, which comprises abrasive grains, magnetic particles, oxidants, dispersion medium, dispersed phase and additives, the abrasive grains are selected from diamond, cubic boron nitride, cerium oxide, silicon carbide or aluminum oxide, the magnetic particles are selected from carbonyl iron powder, ferroferric oxide or cobalt ferrite; the oxidants are selected from hydrogen peroxide, ammonium persulfate, potassium permanganate or ferric nitrate; the dispersion medium is selected from polyethylene glycol, deionized water or silicone oil; the dispersed phase is selected from silicon dioxide, polymethyl methacrylate microspheres or starch nanoparticles; and the additives are selected from sodium peroxide, aminosiloxane, glycine, benzotriazole, sodium borate or graphene.

[0006] The polishing method provided by the complex inner surface chemical enhancement magnetic shear thickening medium flow polishing method of the application:

[0007] (1) The polishing medium with the double stimulus responses of "magnetic enhancement" and "shear thickening" with chemical effects is prepared, which comprises abrasive grains, magnetic particles, chemical oxidants, dispersion medium, dispersed phase and additives, the abrasive grains are selected from diamond, cubic boron nitride, cerium oxide, silicon carbide or aluminum oxide, the magnetic particles are selected from carbonyl iron powder, ferroferric oxide or cobalt ferrite; the chemical oxidants are selected from hydrogen peroxide, ammonium persulfate, potassium permanganate or ferric nitrate; the dispersion medium is selected from polyethylene glycol, deionized water or silicone oil; the dispersed phase is selected from silicon dioxide, polymethyl methacrylate microspheres or starch nanoparticles; and the additives are selected from sodium peroxide, aminosiloxane, glycine, benzotriazole, sodium borate or graphene;

[0008] (2) The two ends of the complex inner surface workpiece are fixed on the precise magnetic control polishing system by using clamps, so that the channel of the complex inner surface workpiece forms a circulating flow channel with the precise magnetic control polishing system, and different distribution and number of magnetic poles are arranged outside the corresponding area to be machined of the complex inner surface, so as to facilitate the subsequent precise regulation and control of the polishing area;

[0009] (3) The polishing medium is added into the precise magnetic control polishing system, so that the polishing medium flows into the flow channel of the complex inner surface workpiece, and under the constraint of the magnetic field, the magnetic particles in the polishing medium rapidly produce polarization phenomenon, so as to arrange along the direction of the magnetic force line and form "flexible composite particle clusters";

[0010] (4) The pistons at the two ends of the precise magnetic control polishing system are reciprocated to drive the polishing medium to flow along the shape of the complex inner surface workpiece;

[0011] (5) The polishing medium forms a flow field under the conformal flow of the flow channel in the complex inner surface workpiece, resulting in the contact, collision and extrusion of the dispersed phase and the dispersion medium in the polishing medium with the micro-convex peaks of the micro-surface of the workpiece, the cluster phenomenon occurs, the "flexible reinforced composite particle cluster" wrapped with chemical oxidant, magnetic particles and abrasive particles is formed, due to the different undulating degrees of the micro-convex peaks in the complex inner surface, the generation range of the "flexible reinforced composite particle cluster" is inconsistent, so that the chemical oxidant, magnetic particles and abrasive particles with different contents are contained, and the oxidant in the "flexible reinforced composite particle cluster" erodes the micro-convex peaks with different undulations in the complex inner surface of the workpiece to different degrees, so that the soft passivation layer with different oxidation depths is generated;

[0012] (6) The abrasive particles in the "flexible reinforced composite particle cluster" cut the soft passivation layer, and when the shear stress exceeds the critical yield stress of the material of the soft passivation layer, the soft passivation layer is effectively removed by the abrasive particles in the "flexible reinforced composite particle cluster";

[0013] (7) After the soft passivation layer is removed, the original surface of the complex inner surface processing area is exposed to the polishing medium again, and the above process is repeated, so that the workpiece is polished with high efficiency and high quality.

[0014] The beneficial effects of the present application are: 1. The complex inner surface chemical enhanced magnetic shear thickening medium flow polishing method provided by the present application forms a stable "flexible reinforced composite particle cluster", and through the synergistic effect of chemical and mechanical action, a soft passivation layer is quickly generated and removed, and high-efficiency and high-quality polishing of the complex inner surface is realized. 2. The complex inner surface chemical enhanced magnetic shear thickening medium flow polishing method provided by the present application configures different distributions and quantities of magnetic poles outside the corresponding area required to be processed on the complex inner surface, so as to ensure the precise control of the magnetic field in the polishing process, realize localized controlled removal, significantly improve the uniformity of surface material removal, and effectively avoid "over polishing" and "under polishing". BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic diagram of a precise magnetic control polishing system.

[0016] Figure 2 is a microcosmic schematic diagram of the composition of the polishing medium.

[0017] Figure 3 is a microcosmic schematic diagram of the localized erosion of the chemical oxidant.

[0018] Figure 4 is a microcosmic schematic diagram of the removal of the soft passivation layer.

[0019] Figure 5 is a schematic diagram of the chemical enhanced magnetic shear thickening medium flow polishing of a small curvature inner surface.

[0020] Figure 6 is a schematic diagram of flow polishing of a large-curvature inner surface chemical-enhanced magnetic shear thickening medium.

[0021] In the figure: 1-precision magnetic control polishing system, 2-piston, 3-clamp, 4-magnetic pole, 5-workpiece, 6-polishing medium, 7-abrasive particle, 8-microscopic surface of workpiece, 9-magnetic particle, 10-dispersing medium, 11-dispersed phase, 12-flexible composite particle cluster, 13-chemical oxidant, 14-soft passivation layer, 15-flexible enhanced composite particle cluster, 16-magnetic field line, 17-micro-chip, 18-additive. DETAILED DESCRIPTION Specific embodiment one

[0023] Localized high-efficiency conformal polishing is performed on a small-curvature inner surface, as shown in Figure 5 .

[0024] (1) The abrasive particle 7 is selected to be diamond, the magnetic particle 9 is selected to be carbonyl iron powder, the chemical oxidant 13 is selected to be hydrogen peroxide, the dispersing medium 10 is selected to be polyethylene glycol, the dispersed phase 11 is selected to be silicon dioxide, and the additive 18 is selected to be sodium peroxide or glycine. The diamond, carbonyl iron powder, hydrogen peroxide, polyethylene glycol, silicon dioxide, and sodium peroxide are mixed to prepare the polishing medium 6;

[0025] (2) The two ends of the complex inner surface workpiece 5 are fixed on the precision magnetic control polishing system 1 by using the clamp 3, so that the channel of the complex inner surface workpiece 5 forms a circulating flow channel with the precision magnetic control polishing system 1, and different distribution and number of magnetic poles 4 are configured outside the corresponding region to be machined of the complex inner surface, so as to facilitate the subsequent precision control of the polishing region;

[0026] (3) The polishing medium 6 is added to the precision magnetic control polishing system 1, so that the polishing medium 6 flows into the flow channel of the complex inner surface workpiece 5. Under the constraint of the magnetic field, the magnetic particles 9 in the polishing medium 6 rapidly produce polarization phenomenon, so as to arrange along the direction of the magnetic field line 16, and form the “flexible composite particle cluster” 12;

[0027] (4) The piston 2 at the two ends of the precision magnetic control polishing system 1 is reciprocated to drive the polishing medium 6 to flow along the complex inner surface workpiece 5;

[0028] (5) The polishing medium 6 forms a flow field under the conformal flow of the flow channel in the complex inner surface workpiece 5, which causes the dispersed phase 11 and the dispersed medium 10 in the polishing medium 6 to contact, collide and squeeze the micro-protrusions of the workpiece micro-surface 8, resulting in a clustering phenomenon and forming a “flexible reinforced composite particle cluster” 15 that encapsulates chemical oxidant 13, magnetic particles 9 and abrasive particles 7. Due to the different undulations of the micro-protrusions in the complex inner surface, the generation range of the “flexible reinforced composite particle cluster” 15 is inconsistent, thus containing different contents of chemical oxidant 13, magnetic particles 9 and abrasive particles 7. The chemical oxidant 14 erodes the micro-protrusions with different undulations in the complex inner surface to different degrees, thereby generating a soft passivation layer 14 with different oxidation depths.

[0029] (6) The abrasive particles 7 in the "flexible reinforced composite particle cluster" 15 cut against the soft passivation layer 14. When the shear stress exceeds the material critical yield stress of the soft passivation layer 14, the soft passivation layer 14 is effectively removed by the abrasive particles 7 in the "flexible reinforced composite particle cluster" 15.

[0030] (7) After the soft passivation layer 14 is removed, the original surface of the complex inner surface processing area is re-exposed to the polishing medium 6, and the above process is repeated to achieve high-efficiency and high-quality polishing of the workpiece 5. Specific Implementation Example 2

[0032] Localized, high-efficiency conformal polishing using large-curvature inner surfaces, such as... Figure 6 As shown.

[0033] (1) Abrasive particles 7 are silicon carbide, magnetic particles 9 are iron oxide, chemical oxidant 13 is ammonium persulfate; dispersion medium 10 is silicone oil; dispersed phase 11 is silicon dioxide; additive 18 is sodium peroxide or glycine. Silicon carbide, iron oxide, ammonium persulfate, silicone oil, silicon dioxide and sodium peroxide are mixed to prepare polishing medium 6.

[0034] (2) Fix the two ends of the complex inner surface workpiece 5 to the precision magnetron polishing system 1 using the clamp 3, so that the channel of the complex inner surface workpiece 5 and the precision magnetron polishing system 1 form a circulating flow channel, and configure magnetic poles 4 with different distributions and numbers on the outside of the corresponding area to be processed on the complex inner surface, so as to facilitate the precise control of the subsequent polishing area.

[0035] (3) Add polishing medium 6 to precision magnetron polishing system 1, so that polishing medium 6 flows into the flow channel of complex inner surface workpiece 5. Under the constraint of magnetic field, magnetic particles 9 in polishing medium 6 quickly generate polarization phenomenon, so that they are arranged along the direction of magnetic field line 16 to form "flexible composite particle cluster" 12.

[0036] (4) Through the circulation reciprocating motion of the piston 2 at both ends of the precision magnetic control polishing system 1, the polishing medium 6 is driven to follow the shape of the flow channel of the complex inner surface workpiece 5 to flow along the shape;

[0037] (5) The polishing medium 6 forms a flow field in the flow channel of the complex inner surface workpiece 5, resulting in the dispersed phase 11 and the dispersion medium 10 in the polishing medium 6 contacting, colliding and extruding the micro-convex peaks of the micro-surface 8 of the workpiece, and the cluster phenomenon occurs, forming the "flexible reinforced composite particle cluster" 15 wrapped with the chemical oxidant 13, the magnetic particle 9 and the abrasive particle 7. Due to the different undulating degrees of the micro-convex peaks in the complex inner surface, the generation range of the "flexible reinforced composite particle cluster" 15 is inconsistent, so that the chemical oxidant 13, the magnetic particle 9 and the abrasive particle 7 are contained in different amounts. The chemical oxidant in it erodes the micro-convex peaks with different undulations in the complex inner surface to different degrees, thereby generating soft passivation layers 14 with different oxidation depths;

[0038] (6) The abrasive particles 7 in the "flexible reinforced composite particle cluster" 15 cut the soft passivation layer 14, and when the shear stress exceeds the critical yield stress of the material of the soft passivation layer 14, the soft passivation layer 14 is effectively removed by the abrasive particles 7 in the "flexible reinforced composite particle cluster" 15;

[0039] (7) After the soft passivation layer 14 is removed, the original surface of the complex inner surface processing area is exposed to the polishing medium 6 again, and the above process is repeated, so as to realize high-efficiency and high-quality polishing of the workpiece 5.

[0040] The above specific embodiments of the present application are only used for illustrative or explanatory purposes of the principles of the present application, and do not constitute a limitation on the protection scope of the present application. Therefore, under the premise of not deviating from the principles and protection scope of the present application, the present application is modified, modified, equivalent replaced, equivalent structure and equivalent process changed, etc., which should be covered within the protection scope of the present application.

Claims

1. A polishing method for complex internal surfaces using chemically enhanced magnetic shear-thickening media, characterized in that: The method is implemented through the following steps: (1) A polishing medium 6 with dual stimulation response of "magnetization enhancement" and "shear thickening" with chemical effect is prepared, including abrasive particles 7, magnetic particles 9, chemical oxidant 13, dispersion medium 10, dispersed phase 11 and additive 18. The abrasive particles 7 are diamond, cubic boron nitride, cerium oxide, silicon carbide or alumina. The magnetic particles 9 are carbonyl iron powder, iron tetroxide or cobalt ferrite. The chemical oxidant 13 is hydrogen peroxide, ammonium persulfate, potassium permanganate or ferric nitrate. The dispersion medium 10 is polyethylene glycol, deionized water or silicone oil. The dispersed phase 11 is silica, polymethyl methacrylate microspheres or starch nanoparticles. The additive 18 is sodium peroxide, aminosiloxane, glycine, benzotriazole, sodium borate or graphene. (2) Fix the two ends of the complex inner surface workpiece 5 to the precision magnetic polishing system 1 using the clamp 3, so that the channel of the complex inner surface workpiece 5 and the precision magnetic polishing system 1 form a circulating flow channel, and configure magnetic poles 4 with different distributions and numbers on the outside of the corresponding area to be processed on the complex inner surface, so as to facilitate the precise control of the magnetic field of the subsequent polishing area. (3) Add polishing medium 6 to the precision magnetron polishing system 1, so that polishing medium 6 flows into the flow channel of complex inner surface workpiece 5. Under the constraint of magnetic field, the magnetic particles 9 in polishing medium 6 quickly generate polarization phenomenon, so that they are arranged along the direction of magnetic field line 16 to form "flexible composite particle cluster" 12. (4) The pistons 2 at both ends of the precision magnetic polishing system 1 reciprocate in a cycle, causing the polishing medium 6 to flow in a conformal manner with the flow channel of the complex inner surface workpiece 5. (5) The polishing medium 6 forms a flow field under the conformal flow of the flow channel in the complex inner surface workpiece 5, which causes the dispersed phase 11 and the dispersed medium 10 in the polishing medium 6 to contact, collide and squeeze the micro-protrusions of the workpiece micro-surface 8, resulting in a clustering phenomenon and forming a "flexible reinforced composite particle cluster" 15 that encapsulates chemical oxidant 13, magnetic particles 9 and abrasive particles 7. Due to the different undulations of the micro-protrusions in the complex inner surface, the generation range of the "flexible reinforced composite particle cluster" 15 is inconsistent, thus containing different contents of chemical oxidant 13, magnetic particles 9 and abrasive particles 7. The chemical oxidant 13 erodes the micro-protrusions with different undulations in the complex inner surface to different degrees, thereby generating a soft passivation layer 14 with different oxidation depths. (6) The abrasive particles 7 in the "flexible reinforced composite particle cluster" 15 cut against the soft passivation layer 14. When the shear stress exceeds the material critical yield stress of the soft passivation layer 14, the soft passivation layer 14 is effectively removed by the abrasive particles 7 in the "flexible reinforced composite particle cluster" 15. (7) After the soft passivation layer 14 is removed, the original surface of the complex inner surface processing area is re-exposed to the polishing medium 6, and the above process is repeated to achieve high-efficiency and high-quality polishing of the workpiece 5.

2. The polishing method for a complex internal surface chemically enhanced magnetic shear thickening medium flow according to claim 1, characterized in that: By changing the configuration of the magnetic poles 4 in the processing area, using NSNS, NNSS, NSSN, and SNNS magnetic pole arrangements, localized and controllable polishing of complex inner surfaces with different geometric features can be achieved.

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