阅读说明：本技术 一种磁流变凝胶柔性砂轮 (Magnetorheological gel flexible grinding wheel ) 是由 张高峰 王佳坤 吴高灿 罗德晶 刘达 蔡剑波 邓鑫 于 2021-01-07 设计创作，主要内容包括：本发明公开了一种磁流变凝胶柔性砂轮,属于对磁流变凝胶的一种新的应用方式,将粘弹性可控的磁流变凝胶充当砂轮磨削的控力介质,属于磁流智能材料的应用和磨削加工领域。磁流变凝胶是由基体的和磁性颗粒组成的。磁流变凝胶柔性砂轮包括磁场发生装置、磁流变凝胶容器、装夹装置和磨削部分。本发明提供的磁流变凝胶柔性砂轮能够随外界电流的变化产生可控的磁场,通过磁场对磁流变凝胶的影响,达到控制磨削力的目的。本发明提供的柔性砂轮旨在改善磨削镍基单晶高温合金时磨削力大、磨削温度高、磨削变质层厚度大等问题。(The invention discloses a magnetorheological gel flexible grinding wheel, belongs to a new application mode of magnetorheological gel, uses magnetorheological gel with controllable viscoelasticity as a force control medium for grinding of the grinding wheel, and belongs to the field of application and grinding processing of magnetorheological intelligent materials. The magnetorheological gel is composed of a matrix and magnetic particles. The magnetorheological gel flexible grinding wheel comprises a magnetic field generating device, a magnetorheological gel container, a clamping device and a grinding part. The magnetorheological gel flexible grinding wheel provided by the invention can generate a controllable magnetic field along with the change of external current, and the purpose of controlling the grinding force is achieved through the influence of the magnetic field on the magnetorheological gel. The flexible grinding wheel provided by the invention aims to solve the problems of large grinding force, high grinding temperature, large thickness of a grinding deterioration layer and the like in the process of grinding the nickel-based single crystal superalloy.)

1. The magnetorheological gel is characterized by comprising a high-viscosity polymer matrix and magnetic particles.

2. The magnetorheological gel of claim 1, wherein the high viscosity polymer matrix is polyurethane and the magnetic particles are carbonyl iron powder.

3. The magnetorheological gel of claim 1, wherein the polyurethane matrix is comprised of 4, 4-diphenylmethane diisocyanate (MDI) and Castor Oil (CO); the magnetic particles are carbonyl iron powder with the average particle size of 4.5 mu m.

4. The magnetorheological gel of claim 1, wherein the polyurethane matrix is synthesized from CO and MDI in a molar ratio of 3:2 at 80 ℃ with heating and stirring and with the addition of a catalyst, a chain agent, and a plasticizer.

5. The magnetorheological gel of claim 1, wherein the carbonyl iron powder is present in the magnetorheological gel in an amount of about 60 wt.%.

6. The magnetorheological gel of claim 1, wherein the ratio of the total amount of the components according to CO: the magnetorheological gel prepared with MDI molar ratio of 3:1 to 2:1 and carbonyl iron particle mass fraction of 40-70 wt% has good mechanical property and good sedimentation stability.

7. The magnetorheological gel flexible grinding wheel is characterized by further comprising: the magnetorheological fluid grinding device comprises a magnetic field generating device, a magnetorheological gel container and a grinding area.

8. The magnetorheological gel flexible grinding wheel according to claim 7, wherein the magnetic field generator comprises a cylindrical base iron, an excitation coil, a metal disc, a magnetic conductive plate, a copper sleeve and a large copper ring.

9. The magnetorheological gel flexible grinding wheel according to claim 7, wherein the magnetorheological gel container comprises a magnetorheological gel filling area, a rubber outer ring, a rubber plug, a magnetic conducting plate and a base.

10. The magnetorheological gel flexible grinding wheel according to claim 7, wherein the grinding zone consists essentially of a CBN sanding belt adhered to a rubber outer ring.

11. The preparation method of the magnetorheological gel flexible grinding wheel is characterized by comprising the following steps:

firstly, processing raw materials for synthesizing polyurethane, heating the raw materials to 110 ℃ by using a vacuum drying oven, removing water possibly existing in CO, and melting solid MDI in the vacuum drying oven at 80 ℃; and then adding CO and MDI (diphenyl-methane-diisocyanate) according to a certain proportion in an 80 ℃ oil bath thermostat, mechanically stirring for half an hour by using a stirrer, adding carbonyl iron powder, properly increasing the rotating speed of the stirrer, stirring for one hour, placing in a vacuum drying oven for vacuumizing, setting the temperature to 80 ℃, placing for 15 minutes, taking out, stirring for 30 minutes, repeating for 3 times, and placing at room temperature for deep vulcanization for 3 days to obtain a finished product.

Two, magnetic field generator's preparation, excitation coil use 0.5 mm's enameled copper line, and cylindrical base iron is encircleed to excitation coil, and the magnetic circuit line moves towards: the magnetic-rheological magnetic.

Preparing a magnetorheological gel container and a grinding area, wherein the magnetorheological gel container is formed by bonding a rubber outer ring, a base and two magnetic conduction plates; the base is tightly attached to the large copper ring, and the CBN abrasive belt with the same size is bonded to the outer rubber ring to serve as a grinding area.

12. The magnetorheological gel flexible grinding wheel is characterized in that the grinding wheel is ground by a grinding area under the magnetic field generated by the magnetic field generating device of claim 7 by using the magnetorheological gel of claim 1; the magnetorheological gel flexible grinding wheel is connected with the main shaft of the high-precision numerical control surface grinding machine through a flange plate.

Technical Field

The invention belongs to the field of grinding processing assisted by intelligent materials and grinding wheel manufacturing, and particularly relates to preparation of polyurethane magnetorheological gel and design of a magnetorheological gel flexible grinding wheel.

Background

The nickel-based single crystal superalloy has more excellent high-temperature creep and fatigue properties compared with the traditional superalloy, and has become a key material for manufacturing the turbine blade of the aerospace engine in recent years. At present, the nickel-based single crystal blade is processed by adopting the traditional manual grinding and abrasive belt grinding and polishing, and has low processing efficiency and poor consistency of processing quality. It is difficult to meet the requirements of high quality and high efficiency of modern industry. However, due to the material particularity, the single crystal blade machined by the existing ultra-precision grinding machining method has the problems of low yield, poor surface quality of a workpiece and difficult machining.

In the process of processing the nickel-based single crystal superalloy by using the traditional grinding technology, the traditional rigid grinding wheel is used for grinding the nickel-based single crystal superalloy, so that the high grinding force is generated, the excessively high grinding temperature is realized, the thickness of a grinding metamorphic layer of the material is large, recrystallization is easy to occur in a high-temperature environment, a crystal boundary is generated, and cracks are easy to generate on the nickel-based single crystal hollow blade with the generated crystal boundary under the service condition.

The magnetorheological material is a novel intelligent material, can generate rapid, continuous and reversible changes under the action of a magnetic field, and can serve as a good force control medium according to the viscoelastic controllable principle.

Therefore, aiming at the defects of the existing rigid grinding method and the viscoelasticity controllable characteristic of the magnetofluid intelligent material, the invention provides the polyurethane magnetorheological gel flexible grinding wheel and the preparation method thereof, which are used for reducing the grinding temperature and the grinding force of the nickel-based single crystal superalloy in the process of grinding the nickel-based single crystal superalloy and reducing the thickness of a grinding deterioration layer of the nickel-based single crystal superalloy.

Disclosure of Invention

The invention provides a magnetorheological gel with high relative magnetorheological effect, good magnetic sensitivity, stable performance and good sedimentation stability, a magnetorheological gel flexible grinding wheel with controllable grinding force and a preparation method thereof. The grinding temperature is too high, and the thickness of a grinding deterioration layer is large.

The invention provides a preparation method of magnetorheological gel, wherein the magnetorheological gel consists of a polyurethane matrix and magnetic particles.

The composition of the magnetorheological gel provided by the invention is further set as follows: the polyurethane matrix is synthesized by mixing 4, 4-diphenylmethane diisocyanate (MDI) and Castor Oil (CO) according to a certain proportion and adding a proper amount of chain extender, plasticizer and catalyst. The magnetic particles are carbonyl iron powder with a certain mass fraction.

Preferably, the molar ratio of MDI to CO is between 3:1 and 2: 1;

the mass fraction of the carbonyl iron powder is preferably 40 to 70 wt%.

The chain extender, the plasticizer and the catalyst during the synthesis of the magnetorheological gel are respectively 1, 4-butanediol, phthalate and stannous octoate.

The invention provides a preparation process of polyurethane magnetorheological gel, which comprises the following process steps:

pouring CO into a 200ml beaker, placing the beaker into a vacuum drying oven, drying the beaker at 110 ℃ for 1 hour, removing excess water for later use, heating the weighed MDI to 80 ℃, dripping the MDI into the CO after the MDI is completely melted, and stirring the mixture in a constant-temperature oil bath box at 80 ℃ for 30 minutes by using a stirrer. Then, a proper amount of chain extender, plasticizer and catalyst are dripped into the beaker, the temperature is kept at 80 ℃ in the whole reaction process, the mechanical stirring speed is moderately increased, and the stirring is carried out for 30 minutes. Then, adding carbonyl iron powder with the mass fraction of 60 wt% into the mixture, properly increasing the rotating speed of a stirrer, stirring for one hour, placing the mixture in a vacuum drying oven with the temperature of 80 ℃ for vacuumizing, placing the mixture for 15 minutes, taking out the mixture, continuing to stir the mixture for 30 minutes, repeating the steps for a plurality of times, and deeply vulcanizing the mixture for 3 days at room temperature to obtain a finished product.

The invention provides a magnetorheological gel flexible grinding wheel which further comprises a magnetorheological gel container, a magnetic field generator, a clamping device and a grinding part.

The magnetorheological gel container includes a base serving as a base; the magnetic conduction plate plays a role in supporting and magnetic conduction; the rubber outer ring is bonded with the grinding part and transmits grinding force; the cavity formed by the three components is filled with magnetic rheological gel.

Preferably, the base is made of resin materials by using a 3D printing technology, and the manufactured finished product has certain rigidity and supporting force and is economical, convenient and quick to manufacture.

Preferably, the rubber outer ring is made of silicone rubber having good oil resistance and high softness.

The magnetic field generator comprises a cylindrical base iron and an excitation coil for generating a magnetic field, and also comprises a metal disc and a magnetic conduction plate.

The metal plate is provided with fine and dense small holes for heat dissipation and a wire inlet and outlet of the excitation coil; in the grinding wheel, the magnetic conduction function is realized, the magnetic leakage is reduced, and the effect of fastening other parts of the grinding wheel is realized under the effect of the clamping device.

Preferably, the magnetic field generator further comprises a rotary electric connector, the rotary electric connector base being connected to the connecting rod for external connection to a power source.

Preferably, the magnetic field generator further comprises a lead, one end of the lead passes through the wire inlet and outlet hole of the metal disc to be connected with the excitation coil, and the other end of the lead is connected with the rotary electric connector to supply power to the excitation coil.

The clamping device mainly comprises a flange plate and a connecting rod, and the magnetorheological gel flexible grinding wheel provided by the invention is connected with the surface grinding machine through the flange plate and is connected with the rotary electric connector through the connecting rod.

The grinding part is mainly ground by using an abrasive belt, and the abrasive belt is adhered to the rubber outer ring of the magnetorheological gel container.

Drawings

FIG. 1 is an overall schematic view of the present invention;

FIG. 2 is a cross-sectional view of the overall construction of the present invention;

FIG. 3 is a half sectional view of the overall structure of the present invention;

FIG. 4 is an overall schematic view of a magnetorheological gel container in accordance with the invention;

FIG. 5 is a cross-sectional view of a magnetorheological gel container in accordance with the invention;

FIG. 6 is a schematic view of a magnetic circuit line according to the present invention;

in the figure: 1. a metal disc; 101. a wire guide hole; 102. heat dissipation holes; 2. a cylindrical base iron; 3. a field coil; 4. a copper sleeve; 5. a copper ring; 6. a magnetorheological gel container; 601. a cavity; 602. a rubber outer ring; 603. a rubber stopper; 604. a magnetic conductive plate; 605. a base; 7. a flange plate; 701. fastening a flange; 702. a flange; 8. fastening a nut; 9. a connecting rod; 10. rotating the electrical connector; 11. an abrasive belt;

Detailed Description

In order to make the technical problems solved by the present invention and the technical solutions adopted in the present invention more clear, the technical solutions of the present invention are further described below by the following detailed description with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative and descriptive of the invention and not restrictive. It should be noted that, for the convenience of description, only some but not all of the elements related to the present invention are shown in the drawings.

In the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., the connection may be a fixed connection or a removable connection; specific meanings thereof within the present invention will be specifically understood as specific cases by those skilled in the art.

All the preparation raw materials of the invention have no special limitation on the sources, can be purchased in the market or prepared by the personnel skilled in the art, have no special requirements on the purity of the preparation raw materials, and are preferably analytically pure.

The invention provides a magnetorheological gel flexible grinding wheel, which comprises: a magnetic field generator for providing a desired magnetic field; the clamping device is used for connecting the grinding wheel and the surface grinding machine; the magnetorheological gel container is used for containing magnetorheological gel and transmitting grinding force; and a grinding portion for grinding the workpiece.

The magnetic field generator comprises a cylindrical base iron (2), an excitation coil (3), a metal disc (1), a rotary electric connector (10) and a magnetic conduction plate (604). The preferable cylindrical base iron (2) is made of magnetic permeability materials such as soft magnetic ferrite or pure iron; preferably, a connecting port is processed in the center of the cylindrical base iron (2) and is connected with the copper sleeve; the excitation coil (3) is preferably an enameled wire and is wound on the outer circle of the cylindrical base iron (2); the metal plate (1) is preferably low-carbon steel with better magnetic conductivity; preferably, a wire guide hole (101) and a heat dissipation hole (102) for the magnet exciting coil (3) to enter and exit are machined in the metal disc (1).

The rotary electric connector (10) is connected with the magnet exciting coil (3) through a lead and is externally connected with a power supply; the inner ring is connected with the connecting rod (9), and the outer ring does not rotate along with the grinding wheel.

Preferably, the external power supply of the rotary electric connector (10) is a controllable variable power supply, and provides controllable variable current to enable the magnetic field generator to generate a controllable variable magnetic field, and the grinding force is controlled according to the controllable principle of the viscoelasticity of the magnetic fluid.

The connecting rod (9) is connected with the fastening nut (8) and the rotary electric connector (10).

The clamping device comprises a pair of flanges (701) (702) and a fastening screw (8). Preferably, the inner conical surface of the flange plate (702) is attached to the main shaft of the surface grinding machine; preferably, a hole is processed in the fastening nut (8) and is connected with the connecting rod (9).

The magnetorheological gel container (6) comprises a cavity (601) for filling magnetorheological gel; a rubber outer ring (602) connected to the grinding portion for transmitting a grinding force; preferably, the rubber outer ring (602) is made of silica gel with good oil resistance and higher softness; the magnetic conduction plate (604) is used for transmitting the magnetic circuit and playing a supporting role; preferably, the magnetic conductive plate is provided with an injection hole for injecting the polyurethane magnetorheological gel; a rubber stopper (603) for blocking the injection hole; the base (605) is used for supporting the container (6) and is a base of the magnetorheological gel container (6); preferably, the base is made of resin materials and is manufactured by using a 3D printing technology, and the base is convenient, quick and economical.

Preferably, the grinding part is ground by using an abrasive belt, the abrasive belt has good flexibility and can be externally attached to a rubber outer ring; preferably, the abrasive belt is a CBN abrasive belt.

The invention provides magnetorheological gel, which is preferable, and has good magnetorheological effect, good mechanical property and high stability.

The invention provides a magnetorheological gel which is composed of a high-viscosity polymer matrix and magnetic particles.

Preferably, the polymer matrix is polyurethane colloid; preferably, the polyurethane colloid is prepared by the reaction of polyol and isocyanate and the addition of additives; preferably, Castor Oil (CO) is used as the polyol of the present invention, and 4, 4-diphenylmethane diisocyanate (MDI) is used as the isocyanate.

Preferably, the additives are generally chain extenders, plasticizers, catalysts; preferably, the chain extender is 1, 4-butanediol; preferably, the plasticizer is phthalate; preferably, the catalyst is stannous octoate.

Preferably, the magnetic particles are carbonyl iron powder; the carbonyl iron powder preferably has a particle size of 3 to 8 μm, more preferably an average particle size of 4.5. mu.m.

The proportion of the raw materials is not particularly limited, and the mol ratio of CO to MDI is preferably 3:1 to 2: 1; the mass fraction of the carbonyl iron powder is preferably 40 to 70 wt%.

The invention also provides a preparation method of the polyurethane magnetorheological gel, which comprises the following steps:

pouring CO into a 200ml beaker, placing the beaker into a vacuum drying oven, drying the beaker at 110 ℃ for 1 hour, removing excess water for later use, heating the weighed MDI to 80 ℃, dripping the MDI into the CO after the MDI is completely melted, and stirring the mixture in a constant-temperature oil bath box at 80 ℃ for 30 minutes by using a stirrer. Then, a proper amount of chain extender, plasticizer and catalyst are dripped into the beaker, the temperature is kept at 80 ℃ in the whole reaction process, the mechanical stirring speed is moderately increased, and the stirring is carried out for 30 minutes. Then adding carbonyl iron powder into the mixture, properly increasing the rotation speed of a stirrer, stirring for one hour, putting the mixture into a vacuum drying box at 80 ℃, vacuumizing, standing for 15 minutes, taking out, continuing to stir for 30 minutes, repeating for several times, and deeply vulcanizing at room temperature for 3 days to obtain a finished product.