WO2020258244A1

WO2020258244A1 - Chemical-mechanical polishing method and polishing device for integral impeller

Info

Publication number: WO2020258244A1
Application number: PCT/CN2019/093669
Authority: WO
Inventors: 张振宇; 廖龙兴; 孟凡宁; 孟祥东
Original assignee: 大连理工大学
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-12-30

Abstract

A chemical-mechanical polishing device for an integral impeller. The device comprises an electric motor (1), a bolt (2), a coupling (9), a mounting plate (3), a positioning support plate (4), a connection piece (10), a base (5), a container (7) and a plastic foam (6), wherein the electric motor (1) is mounted on the base (5) by means of the mounting plate (3) and the positioning support plate (4), and a rotary shaft of the electric motor (1) is connected to an integral impeller (11) by means of the coupling (9) and the connection piece (10). The polishing device is simple in structure, easy to manufacture, convenient to operate, stable and reliable, and low in cost. Further provided is a chemical-mechanical polishing method for an integral impeller, in which method chemical reagents and abrasives are mixed to form a polishing liquid; the whole of the integral impeller is immersed in the polishing liquid and is driven by the electric motor to rotate; under the combined action of chemical corrosion softening of the polishing liquid and mechanical scraping removal, precise polishing of various parts of an integral impeller surface is carried out. The polishing method has strong versatility, high polishing efficiency, and good polishing quality.

Description

Chemical mechanical polishing method and polishing device for integral impeller

Technical field

The invention belongs to the technical field of mechanical processing, and specifically relates to a chemical mechanical polishing method and a polishing device for an integral impeller.

Background technique

The impeller is a key component of power machinery such as turbine engines and turbochargers. Compared with the traditional combined impeller, the new generation of integral impeller is characterized by the design and manufacture of a single blade and the disc as a whole, making it compact and strong. The advantages of high, long service life and large thrust-to-weight ratio are widely used in aerospace, energy and power, ships and other fields.

At present, the processing methods of integral impellers at home and abroad are: precision forging manufacturing, multi-axis CNC milling, electrolytic machining, abrasive flow machining, and manual polishing. Among them, precision forging manufacturing is a manufacturing process for mass production of impellers. This process has high requirements for equipment manufacturing accuracy, high abrasive manufacturing costs, and poor versatility. It is generally used for the blank manufacturing of impellers; multi-axis CNC milling processing is At present, the most commonly used machining method can realize the rough and fine machining of the impeller. However, this machining method requires high rigidity of the machine tool, cutting tool, and fixture. It is necessary to write a special processing program. For impeller processing with small blade spacing Tool interference is prone to occur, the surface processing quality is average, and the roughness Ra≥1.6μm; electrochemical machining is usually used for the finishing of the integral impeller, and special electrodes are required for different blades, and the pre-manufacturing and subsequent correction are difficult; abrasive flow polishing The processing is aimed at the precision polishing of the overall impeller. The process requires very high equipment and high processing costs. There are many parameters that need to be controlled during the processing, such as pressure and cycle times; manual polishing is to improve the surface finish of the overall impeller. Enterprises still use this method, but the manual polishing efficiency is low, the cost is high, the blade profile accuracy is poor, and it is not good for the health of the operator.

In summary, the main problems existing in the processing of integral impellers at home and abroad are: difficulty in manufacturing processing equipment, poor versatility, high cost, low processing efficiency, and poor overall processing quality. To solve this problem, the present invention provides a chemical mechanical polishing method and polishing device for an integral impeller.

technical problem

The purpose of the present invention is to provide an integral impeller polishing method with good polishing quality and high efficiency, and an integral impeller polishing device with simple structure, low cost, convenient operation and good versatility.

Technical solutions

The technical scheme of the present invention:

A chemical mechanical polishing device for integral impeller, including motor 1, bolt 2, mounting plate 3, positioning support plate 4, base 5, plastic foam 6, container 7, polishing liquid 8, coupling 9, connecting piece 10, integral Impeller 11, motor mounting through hole 12, mounting plate through hole 13, positioning support plate through hole 14, shaft end 15, bottom end surface 16, connector through hole 17 and bottom end surface groove 18;

The rotating shaft of the motor 1 passes through the mounting plate 3 downwards, and it is ensured that the motor 1 is vertically installed and fixed on the mounting plate 3; the rotating shaft of the motor 1 is connected to a shaft end of the connecting piece 10 through a coupling 9, and the connecting piece 10 The other end is connected and fixed with the large end face of the integral impeller;

The mounting plate 3 includes two rectangular steel plates with the same structure, which are fixed on the base 5 through a positioning support plate 4; there are four holes in the steel plate, two of which are motor mounting through holes 12 to realize the positioning of the motor 1. Installation: A mounting plate through hole 13 is provided at both ends of the steel plate to realize the positioning and installation of the steel plate;

The supporting and positioning plate 4 includes two "L"-shaped plates with the same structure. The surface of one plate is provided with positioning and supporting plate through holes 14 to realize that the supporting and positioning plate 4 is fixed on the base 5; The threaded holes matched with the through holes 13 of the mounting plate realize the installation of the mounting plate 3;

The connecting piece 10 includes a shaft end 15 and a bottom end surface 16, which are an integral structure. The cross section of the connecting piece 10 is an "inverted T" shape; the bottom end surface of the connecting piece 10 is provided with no less than 3 connecting pieces on the periphery. Hole 17 and the bottom end surface groove 18 in the middle; the outer diameter of the shaft end 15 is the same as that of the motor shaft, the size of the bottom end surface groove 18 and the connecting piece through hole 17 are the same as the integral impeller large end circular boss 19 and the integral impeller large end thread The holes 20 are matched respectively;

The base 5 is provided with a concave cavity and threaded holes, wherein the diameter of the inscribed circle of the concave cavity is greater than or equal to the diameter of the circumscribed circle of the container 7, and the threaded hole matches the through hole 14 of the positioning support plate;

The inner surface of the container 7 has corrosion resistance, and the diameter of the inscribed circle of the container should be larger than the maximum outer diameter of the polished integral impeller;

The container is placed in the concave cavity of the base 5 and the gap between the two is filled with plastic foam 6.

A chemical mechanical polishing method for an integral impeller includes the following steps:

(1) Start the motor at low speed: control the overall impeller speed at 5-9rpm;

(2) Prepare the abrasive. The abrasive includes one or more of alumina abrasive grains, silicon carbide abrasive grains, and boron carbide abrasive grains. The abrasive grain size includes one or two of 1000μm, 150μm, and 45μm. Mix of the above;

(3) Prepare a chemical polishing liquid: the polishing liquid includes an oxidant, a surfactant, a pH regulator and deionized water; the oxidant includes a 65 wt% nitric acid solution and/or a 30 wt% hydrogen peroxide solution, which accounts for the volume of the polishing solution The ratio is 5-12%; the surfactant is a 10 wt% nonylphenol polyoxyethylene ether solution, and its volume ratio in the polishing liquid is 0.1~0.5%; the pH adjuster is 85 wt% phosphoric acid solution and/or 40 wt% hydrofluoric acid solution, adjust the polishing liquid pH to 0.5~3;

(4) Slowly add the abrasive and chemical polishing liquid prepared in step 2) and step 3) to the container at the same time; after the abrasive and chemical polishing liquid are mixed, the integral impeller needs to be completely immersed, and the volume of the chemical polishing liquid and the abrasive The ratio is controlled at 1:1~2;

(5) After the abrasive and chemical polishing liquid are added, increase the motor speed to control the rotation speed of the overall impeller at 60~110rpm. After polishing for 60~90 minutes, turn off the motor, disassemble the overall impeller, and clean it with absolute ethanol. Blow dry to complete the entire polishing process.

Beneficial effect

The beneficial effect of the present invention is that the present invention proposes a method for chemical mechanical polishing of an integral impeller. By developing a polishing liquid mixed with chemical reagents and abrasives, the integral impeller is rotated in the polishing liquid under the drive of a motor. When chemical reagents react with various parts on the surface of the integral impeller, the surface material structure is corroded and softened. Coupled with the mechanical removal of abrasives, the uneven parts on the surface of the integral impeller are scraped off to achieve high precision and high efficiency processing. It can be applied to precision polishing processing of integral impellers of various sizes; in addition, the invention also provides a device of the polishing method, which has simple structure, convenient manufacture, easy operation, stability and reliability, and low cost.

Description of the drawings

Figure 1 is a front view of the chemical mechanical polishing assembly of the integral impeller;

Figure 2 is an oblique two-dimensional view of the chemical mechanical polishing assembly of the integral impeller;

Figure 3 is a cross-sectional view of the connector parts;

Figure 4 is a schematic diagram of the structure of integral impeller parts;

Figure 5 is a curve diagram of the roughness detection result at a certain point of the integral impeller blade;

In the picture: 1 motor; 2 bolts; 3 mounting plate; 4 positioning support plate; 5 base; 6 plastic foam; 7 container; 8 polishing liquid; 9 coupling; 10 connecting piece; 11 integral impeller; 12 motor mounting through hole 13 mounting plate through hole; 14 positioning support plate through hole; 15 connecting piece shaft end; 16 connecting piece bottom end surface; 17 connecting piece through hole; 18 connecting piece bottom end surface groove; 19 integral impeller large end surface circular boss; 20 integral impeller large end face threaded hole; 21 integral impeller large end face; W integral impeller speed.

Embodiments of the invention

The specific embodiments of the present invention will be further described below with reference to the drawings and technical solutions.

Taking the centrifugal integral impeller with a large end face diameter of φ500mm and a material of FV520B as an example, the polishing method and the specific implementation process of the polishing device are described with reference to Figures 1 to 5:

The polishing device of the integral impeller includes: a motor 1, a bolt 2, a mounting plate 3, a supporting and positioning plate 4, a base 5, a plastic foam 6, a container 7, a coupling 9 and a connecting piece 10.

In this example, a plastic drum 7 with an inner diameter of φ540mm and an outer diameter of φ550mm is selected and placed in the circular cavity of the cast iron base 5. The diameter of the circular cavity is φ570mm. The gaps are filled with plastic foam 6, and the base 5 is also provided with threaded holes matching the through holes 14.

Choose a three-phase asynchronous motor 1 with a maximum power of 1.5KW, install it vertically on the mounting plate 3 with bolts 2 so that its shaft faces downwards, and use a coupling 9 to connect the shaft to a shaft of the connecting piece 10 The ends 15 are connected, and the bottom end surface 16 of the connecting member 10 is connected and fixed to the large end surface 21 of the integral impeller.

The mounting plate 3 includes two rectangular steel plates with the same structure, two motor mounting through holes 12 are provided in the middle of the steel plates, and a through hole 13 is provided at each end.

The supporting and positioning plate 4 includes two "L"-shaped plates with the same structure. Both ends of a horizontal plane of the plate are provided with a through hole 14, and the two ends of the vertical plane perpendicular to the surface are provided with a threaded hole. The through holes 13 on the mounting board 3 match.

The connecting piece 10 includes a shaft end 15 and a bottom end surface 16. The bottom end surface is provided with three through holes 17 and a circular groove 18; the outer diameter of the shaft end 15 is the same as the shaft of the motor 1, the circular groove 18 and The relevant size of the through hole 17 matches the circular boss 19 and the threaded hole 20 on the large end face 21 of the integral impeller 11.

The chemical mechanical polishing method of integral impeller, its specific operation steps are as follows:

1) Start motor 1 and set the impeller speed W to 6rpm.

2) Prepare silicon carbide abrasives with particle sizes of 1000 μm, 150 μm, and 45 μm, and mix the three abrasives with equal volume.

3) Prepare the chemical polishing solution; the components in the polishing solution are specifically: the volume fraction of the 65% by weight nitric acid solution in the polishing solution is 4%, and the 30% by weight hydrogen peroxide solution in the polishing solution The volume fraction of the nonylphenol polyoxyethylene ether solution with a mass fraction of 5% and a mass fraction of 10 wt% in the polishing liquid is 0.5%, the remaining volume ratio is deionized water, and the mass fraction is 85 wt% The phosphoric acid solution adjusts the pH of the polishing liquid solution to 1.2.

4) Slowly add step 2) and step 3) the prepared abrasive and chemical polishing liquid to the container 7 until the mixed polishing liquid 8 completely immerses the integral impeller 11; the volume ratio of the abrasive to the chemical polishing liquid is 4 : 3.

5) After the abrasive and chemical polishing liquid are added, increase the rotation speed of the motor 1 to make the overall impeller rotation speed W 78rpm.

6) After polishing for 80 minutes, turn off the motor 1, disassemble the integral impeller 11, clean it with absolute ethanol, and blow dry to complete the entire polishing process.

7) Use a roughness meter to measure the roughness of the polished surface of the integral impeller blade. In this example, the measurement result is Ra0.4~0.7μm. As shown in Figure 5, the roughness test result curve at a certain point on the surface of the integral impeller blade Ra0.502μm.

The content described in the embodiments of this specification is merely an enumeration of the realization forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments. The protection scope of the present invention also includes those skilled in the art. Equivalent technical means conceivable according to the inventive concept.

Claims

A chemical mechanical polishing device for an integral impeller (11), characterized in that the chemical mechanical polishing device includes a motor (1), a bolt (2), a mounting plate (3), a positioning support plate (4), and a base ( 5), plastic foam (6), container (7), polishing liquid (8), coupling (9), connecting piece (10), integral impeller (11), motor mounting through hole (12), mounting plate through Hole (13), positioning support plate through hole (14), shaft end (15), bottom end surface (16), connector through hole (17) and bottom end surface groove (18);

The shaft of the motor (1) passes through the mounting plate (3) downwards, and it is ensured that the motor (1) is vertically installed and fixed on the mounting plate (3); the shaft of the motor (1) is connected to the mounting plate (3) through a coupling (9) One shaft end of the connecting piece (10) is connected, and the other end of the connecting piece (10) is connected and fixed with the large end surface of the integral impeller (11);

The mounting plate (3) includes two rectangular steel plates with the same structure, which are fixed on the base (5) through the positioning support plate (4); the steel plate has four holes, two of which are motor mounting through holes ( 12) To realize the positioning and installation of the motor (1); a mounting plate through hole (13) is provided at both ends of the steel plate to realize the positioning and installation of the steel plate;

The supporting and positioning plate (4) includes two "L"-shaped plates with the same structure, and a positioning supporting plate through hole (14) is opened on the surface of one plate, so that the supporting and positioning plate (4) is fixed on the base (5) ; There is a threaded hole matching the through hole (13) of the mounting plate on the other support plate to realize the installation of the mounting plate (3);

The connecting piece (10) includes a shaft end (15) and a bottom end surface (16), which are an integral structure, and the cross section of the connecting piece (10) is an "inverted T" shape; the bottom end surface of the connecting piece (10) is provided with There are no less than 3 connecting part through holes (17) on the periphery and the bottom end surface groove (18) in the middle; the outer diameter of the shaft end (15) is the same as the motor shaft, the bottom end surface groove (18) and the connecting part through hole ( 17) The size of the integral impeller large end circular boss (19) and the integral impeller large end threaded hole (20) respectively match;

The base (5) is provided with a concave cavity and threaded holes, wherein the diameter of the inscribed circle of the concave cavity is greater than or equal to the diameter of the circumscribed circle of the container (7), and the threaded hole matches the through hole (14) of the positioning support plate ；

The inner surface of the container (7) has corrosion resistance, and the diameter of the inscribed circle of the container should be larger than the maximum end surface outer diameter of the polished integral impeller (11);

The container is placed in the concave cavity of the base (5), and the gap between the two is filled with plastic foam (6).
A chemical mechanical polishing method for an integral impeller (11) is characterized in that it comprises the following steps:

(1) Start the motor at low speed: control the speed of the integral impeller (11) at 5-9rpm;

(2) Prepare the abrasive. The abrasive includes one or more of alumina abrasive grains, silicon carbide abrasive grains, and boron carbide abrasive grains. The abrasive grain size includes one or two of 1000μm, 150μm, and 45μm. Mix of the above;

(3) Prepare a chemical polishing liquid: the polishing liquid includes an oxidant, a surfactant, a pH regulator and deionized water; the oxidant includes a 65 wt% nitric acid solution and/or a 30 wt% hydrogen peroxide solution, which accounts for the volume of the polishing solution The ratio is 5-12%; the surfactant is a 10 wt% nonylphenol polyoxyethylene ether solution, and its volume ratio in the polishing liquid is 0.1~0.5%; the pH adjuster is 85 wt% phosphoric acid solution and/or 40 wt% hydrofluoric acid solution, adjust the polishing liquid pH to 0.5~3;

(4) Slowly add the abrasive and chemical polishing liquid prepared in step 2) and step 3) to the container at the same time; after the abrasive and chemical polishing liquid are mixed, the integral impeller (11) needs to be completely immersed, where the chemical polishing liquid and The volume ratio of abrasive is controlled at 1:1~2;

(5) After the abrasive and chemical polishing solution are added, increase the motor speed to control the rotation speed of the integral impeller (11) at 60~110rpm. After polishing for 60~90min, turn off the motor and disassemble the integral impeller (11). Clean with water and ethanol and blow dry to complete the entire polishing process.