阅读说明：本技术 一种针对制氧机透平导叶的分段离焦激光抛光方法 (Segmented defocusing laser polishing method for turbine guide vane of oxygen generator ) 是由 姚建华 黄锦榜 王梁 吴国龙 于 2020-12-11 设计创作，主要内容包括：本发明提供了一种针对制氧机透平导叶的分段离焦激光抛光方法,采用激光抛光的方式对透平导叶粗糙表面进行高效抛光,利用激光抛光设备不同离焦量下具有相同的抛光效果的特点来对透平导叶不规则粗糙表面进行分段离焦抛光；本发明根据激光抛光设备的离焦量范围以及透平导叶的尺寸形状,对其待抛光侧面进行分段,在具有相同抛光效果的离焦量范围内,通过对不同分段进行激光抛光,使得导叶不规则表面能实现全覆盖抛光；本发明避免了为抛光不规则曲面而引入机械手和三维振镜而带来的超高的成本和控制系统复杂的问题,具有加工精度高,工艺过程简单,对基体材料影响小的特点。(The invention provides a sectional defocusing laser polishing method for a turbine guide vane of an oxygen generator, which is characterized in that the rough surface of the turbine guide vane is efficiently polished in a laser polishing mode, and the irregular rough surface of the turbine guide vane is subjected to sectional defocusing polishing by utilizing the characteristic that laser polishing equipment has the same polishing effect under different defocusing amounts; according to the defocusing range of laser polishing equipment and the size and shape of a turbine guide vane, the side face to be polished of the turbine guide vane is segmented, and in the defocusing range with the same polishing effect, the irregular surface of the guide vane can be polished in a full-covering mode by performing laser polishing on different segments; the invention avoids the problems of ultrahigh cost and complex control system caused by introducing a mechanical arm and a three-dimensional galvanometer for polishing irregular curved surfaces, and has the characteristics of high processing precision, simple process and small influence on base materials.)

1. A segmented defocusing laser polishing method for a turbine guide vane of an oxygen generator is characterized by comprising the following steps:

(1) cleaning and drying the side surface of the turbine guide vane to be polished, then placing and fixing the turbine guide vane in an atmosphere protection box of which the top end is provided with a laser lens, wherein a laser head is arranged above the atmosphere protection box;

continuously introducing argon into the atmosphere protection box;

(2) according to the defocusing amount range of the laser polishing equipment under the same polishing effect, combining the overall dimensions of guide vanes of different models, segmenting the side surface to be polished of the turbine guide vane, and determining the position and the size of a polishing scanning area;

(3) setting the laser power, scanning speed, switching optical delay time, scanning area filling mode and filling line spacing of laser polishing equipment;

the laser power is 100-300W, the scanning speed is 100-500 mm/s, the scanning area filling mode is transverse scanning and longitudinal superposition, and the space between filling lines is 0.02-0.05 mm;

in order to ensure the quality of a lap joint zone between a scanning area and the area, when the scanning speed is v, the switching optical delay time is T, the scanning galvanometer acceleration is a, the galvanometer swing stable time is T-v/a, the switching optical delay time is set to be T-T-v/a, and the width range of the lap joint zone is 1-2 mm;

(4) starting a laser, and polishing the set scanning area by laser beams in sequence;

(5) and stopping the laser, and finishing the full-coverage laser polishing of the irregular rough side surface of the turbine guide vane.

2. The method for polishing the turbine guide vane of the oxygen generator by the segmented defocusing laser as claimed in claim 1, wherein in the step (1), the material of the turbine guide vane is stainless steel.

3. The sectional defocusing laser polishing method for the turbine guide vane of the oxygen generator as claimed in claim 1, wherein in the step (1), the flow rate of argon introduced into the atmosphere protection box is 5-30L/min.

4. The method for polishing the turbine guide vane of the oxygen generator by the segmented defocusing laser as claimed in claim 1, wherein in the step (1), the laser lens can transmit laser beams with the wavelength of 193-1064 nm.

5. The method for polishing the turbine guide vane of the oxygen generator by the segmented defocusing laser as claimed in claim 1, wherein in the step (2), the scanning area is a rectangular area with the length of 5-80 mm and the width of 5-30 mm, and the length and the width of the scanning area are 1mm more than the edge of the side face to be polished, so that the side face to be polished is covered.

6. The method for polishing the turbine guide vane of the oxygen generator by the segmented defocusing laser as claimed in claim 1, wherein in the step (4), the number of polishing times of the scanning area is 1-4, and each subsequent scanning and the previous scanning form an orthogonal direction.

Technical Field

The invention relates to a segmented defocusing laser polishing method for a turbine guide vane of an oxygen generator.

Background

Laser polishing is a novel laser processing technology, and a focused laser beam spot acts on a rough original metal surface to enable a raised thin layer on the surface of a metal material to generate melting and evaporation phenomena, and the raised thin layer flows due to the action of the surface tension and gravity of the material to fill up the sunken part of the metal surface and solidify, so that the ideal polished material surface is finally obtained. Since laser polishing only works on a material layer with a thickness of micrometers, the laser polishing has higher processing precision compared with the metal processed by a common laser beam. The polishing method has the advantages of small environmental pollution, high polishing precision, wide range of polishing materials, incomparable polishing of micro areas and the like.

The turbine guide vane is a main component for regulating the air flow in an expansion machine of an oxygen generator, and can only be cut and molded by adopting a wire cut electrical discharge machining mode at present due to the irregular shape structure of the turbine guide vane. However, the wire-cut surface has a large surface roughness (Ra ≈ 4 μm) due to the instantaneous high-temperature erosion by the spark, resulting in a decrease in the capacity and efficiency of the air flow circulation between the guide vanes. In addition, during long-term service, the surface of the guide vane is subject to fouling and corrosion over time due to inevitable mixing of foreign matter into the flowing air, and the surface roughness is also increased. In order to reduce the surface roughness of the guide vane and improve the operating efficiency of the oxygen generator, the surface of the turbine guide vane needs to be polished.

Currently, the polishing of rough surfaces of turbine guide vanes is mainly based on traditional polishing methods (manual polishing, chemical polishing and electrochemical polishing). The manual polishing mode has two main problems that the irregular surface cannot be precisely polished, the manual polishing work intensity is high, and the like. The chemical and electrochemical polishing methods cause environmental pollution, and the polishing efficiency of both methods is too low. The traditional idea of laser polishing of irregular curved surfaces is to provide a three-dimensional galvanometer and a multi-axis manipulator for a laser polishing system for processing, but the cost is increased and the control system is complicated.

Disclosure of Invention

The invention provides a segmented defocusing laser polishing method for a turbine guide vane of an oxygen generator, aiming at overcoming the defects in the traditional polishing technology of the turbine guide vane of the existing oxygen generator and the problem of equipment cost increase caused by curved surface polishing. The rough surface of the turbine guide vane is efficiently polished by adopting a laser polishing mode, and the irregular rough surface of the turbine guide vane is sectionally polished by using the characteristic that the laser polishing equipment has the same polishing effect under different defocusing amounts.

The technical scheme of the invention is as follows:

a segmented defocusing laser polishing method for a turbine guide vane of an oxygen generator comprises the following steps:

(1) cleaning and drying the side surface of the turbine guide vane to be polished, then placing and fixing the turbine guide vane in an atmosphere protection box of which the top end is provided with a laser lens, wherein a laser head is arranged above the atmosphere protection box;

the material of the turbine guide vane is stainless steel, such as 304, 316L and the like;

continuously introducing argon into the atmosphere protection box, wherein the flow of the argon is 5-30L/min;

the laser lens can transmit laser beams with the wavelength of 193-1064 nm;

(2) according to the defocusing amount range of the laser polishing equipment under the same polishing effect, combining the overall dimensions of guide vanes of different models, segmenting the side surface to be polished of the turbine guide vane, and determining the position and the size of a polishing scanning area;

the scanning area is a rectangular area with the length of 5-80 mm and the width of 5-30 mm, the length and the width of the scanning area are 1mm more than the edge of the side surface to be polished, and the side surface to be polished is ensured to be covered;

(3) setting the laser power, scanning speed, switching optical delay time, scanning area filling mode and filling line spacing of laser polishing equipment;

the laser power is 100-300W, the scanning speed is 100-500 mm/s, the scanning area filling mode is transverse scanning and longitudinal superposition, and the space between filling lines is 0.02-0.05 mm;

in order to ensure the quality of a lap joint zone between a scanning area and the area, when the scanning speed is v, the switching optical delay time is T, the scanning galvanometer acceleration is a, the galvanometer swing stable time is T-v/a, the switching optical delay time is set to be T-T-v/a, and the width range of the lap joint zone is 1-2 mm;

(4) starting a laser, and polishing the set scanning area by laser beams in sequence;

the polishing frequency of the scanning area is 1-4 times, and each subsequent scanning and the previous scanning form an orthogonal direction so as to achieve a better polishing effect;

(5) and stopping the laser, and finishing the full-coverage laser polishing of the irregular rough side surface of the turbine guide vane.

The surface material of the turbine guide vane is heated by laser, so that the rough thin layer of the convex material generates a melting flow phenomenon, the concave part of the metal surface is filled and solidified, and the flat polished surface is finally obtained. The turbine guide vane is placed in an atmosphere protection box, and argon is continuously introduced into the protection box to prevent the surface of the turbine guide vane from being oxidized in the laser polishing process. The laser spot size reaches 100-200 mu m after being focused by the focusing field lens, and high-precision fine machining of the surface of the turbine guide vane can be realized. Under the conditions of 100-300W laser power and 100-500 mm/s scanning speed, the rough surface material of the turbine guide vane is quickly melted and solidified, the depth of a remelted layer is shallow, and the performance of a base material is not affected. The number of polishing times for the scanned area can be increased to achieve a better polishing effect.

The invention has the beneficial effects that:

the method applies the laser polishing technology to polishing the turbine guide vane of the oxygen generator, can realize the high-efficiency polishing of the irregular rough surface of the turbine guide vane by utilizing the advantages of high laser action efficiency, small focusing light spot, high processing precision and certain focal depth range, and has simple process and great advantages compared with the traditional polishing method of the irregular rough surface of the turbine guide vane;

the remelting effect is only generated on the material layer with the thickness of micron to smooth the rough surface, so that the influence on the base material is small compared with the laser beam processing metal with the macroscopic size of light spots;

according to the invention, by utilizing the characteristic that the laser polishing equipment has the same polishing effect in different defocusing amount ranges, the rough part of the side surface of the turbine guide vane in the defocusing amount range can be effectively polished in a defocusing mode;

according to the defocusing range of laser polishing equipment and the size and shape of a turbine guide vane, the side face to be polished of the turbine guide vane is segmented, and in the defocusing range with the same polishing effect, the irregular surface of the guide vane can be polished in a full-covering mode by performing laser polishing on different segments;

the invention avoids the problems of ultrahigh cost and complex control system caused by introducing a mechanical arm and a three-dimensional galvanometer for polishing irregular curved surfaces.

Drawings

Fig. 1 is a physical diagram of the guide vane of example 1 before polishing.

FIG. 2 is a schematic diagram showing the division of the region to be polished of the guide vane in embodiment 1.

FIG. 3 is a real view of the guide vane of example 1 after polishing.

FIG. 4 is a gold phase diagram of the remelted layer thickness of the guide vane after polishing in example 1.

FIG. 5 is a scan of the three-dimensional profile of the surface of the polished guide vane of example 1.

Detailed Description

The present invention is further illustrated by the following specific examples, but the scope of the invention is not limited thereto.

Example 1

Selecting a stainless steel turbine guide vane in an oxygen generator, wherein the shape of the stainless steel turbine guide vane is as shown in figure 1, the length and width dimensions are 52mm multiplied by 28mm, the thickness is 12mm, and the rough surface is pretreated by cleaning, drying and the like.

According to the defocusing amount range of the same polishing effect of a laser device being-5 to +5mm and the size and shape of a turbine guide vane, the rough surface of the guide vane is divided into 3 areas to be polished, the sizes of the scanning areas are 14 x 45mm, 14 x 25mm and 14 x 65mm respectively, the length and the width of each scanning area are 1mm more than the edge of the side face to be polished, the side face to be polished is covered, a lap joint area with the width of 1mm exists between each divided area, and the dividing schematic diagram is shown in fig. 2. And (3) placing the first guide vane block to-be-polished area upwards in the atmosphere protection box, and fixing the first guide vane block.

The laser power is set to be 250W, the scanning speed is 300mm/s, the light on/off delay time is-1000 mus and +1000 mus respectively, the filling mode is linear transverse scanning and longitudinal superposition, the filling line interval is 0.02mm, the shielding gas is argon, and the shielding gas flow is 15L/min.

And starting a laser to scan the region to be polished of the first section of guide vane.

After the scanning is finished, the second to-be-polished area of the guide vane is placed in the atmosphere protection box upwards and fixed, the laser is started, and the second section to-be-polished area is scanned.

And analogizing in turn until the complete coverage laser polishing of the irregular rough surface of the guide vane is completed, wherein the surface of the guide vane after polishing has no oxidation phenomenon, presents metallic luster and mirror surface effect, has good surface appearance, and is shown in figure 3.

And cutting the section of the polished guide vane sample by linear cutting, and performing metallographic analysis, wherein the metallographic phase of the section of the polished guide vane is shown in FIG. 4, and the thickness of the remelting layer is only 105.31 micrometers. The laser polishing only has shallow melting on the surface and does not influence the performance of the matrix.

The roughness of the polished surface was analyzed by a white light interferometer, and the three-dimensional profile of the laser polished surface was as shown in FIG. 5, and the roughness value Ra was 0.29. mu.m.

Aiming at the problems in the prior polishing technology of the turbine guide vane of the oxygen generator, the invention provides a method for remelting the rough surface of the turbine guide vane by using laser so as to achieve the purpose of surface laser polishing. The method takes laser as a heat source, and utilizes the characteristic that laser polishing equipment has a certain focal depth range to carry out sectional remelting treatment on the rough surface of the turbine guide vane, so that a microcosmic convex material is melted, flows and fills a recess, and inert gas protection is carried out on the whole process, thereby realizing the polishing of the irregular rough surface of the guide vane. The invention can realize the full-coverage polishing of the irregular surface of the turbine guide vane, avoids the problem of high cost caused by introducing a mechanical arm and three-dimensional galvanometer equipment for polishing an irregular curved surface in the traditional polishing mode, and has the advantages of high laser polishing efficiency, simple process, and reliable and easy operation in the whole polishing process.

The embodiments described in this specification are merely exemplary of implementation forms of the inventive concept, and the scope of the present invention should not be considered limited to the specific forms set forth in the embodiments, but rather, should be construed as encompassing equivalent technical means which may be conceived by those skilled in the art based on the inventive concept.