CN105666336A - Abrasive particle flow processing experimental verification method for servo valve element nozzle - Google Patents

Abstract

The invention relates to an experimental verification method of abrasive flow processing of a servo valve spool nozzle. The abrasive flow processing technology is used to polish the inner surface of the micro-aperture channel of the servo valve spool nozzle. For surface detection, firstly, the processed workpiece needs to be cut by wire, after the parts are cleaned, and then the surface roughness of the inner surface of the workpiece, the surface morphology and the elemental composition of the workpiece are detected by corresponding testing instruments, which specifically include the following aspects and steps: (1 ) experimental workpiece; (2) analysis of detection results under a high-power microscope; (3) analysis of detection results of surface roughness. (4) Analysis of detection results of surface topography: (a) Verification analysis of surface quality; (2) Prediction verification analysis of small hole area. The invention demonstrates the validity of the abrasive particle flow processing technology, the micro-abrasion mechanism of the abrasive medium and the demonstration of processing prediction.

Description

Experimental Verification Method for Abrasive Flow Machining of Servo Valve Spool Nozzle

technical field

The invention relates to the technical field of abrasive flow processing, in particular to an experimental verification method for abrasive flow processing of a valve core nozzle of a servo valve.

Background technique

The abrasive flow processing mechanism of the servo valve spool nozzle and the simulation experiment research under different working conditions have proved theoretically that the abrasive flow processing technology can realize the smooth processing of the surface of the machined parts, and through the particles to process the surface Excellent wear characteristics can make the surface morphology of the machined surface tend to be smooth and flat. These theoretical discussions are all to explain the grinding mechanism of AFM technology and the effectiveness of AFM. The most direct method to detect the processing quality of abrasive flow finishing is to detect the surface roughness and surface topography of parts after abrasive flow grinding and finishing. In order to prove the effectiveness of the abrasive flow processing technology of the servo valve spool nozzle, the present invention conducts an abrasive flow finishing experiment on the servo valve spool nozzle parts, and then conducts surface quality inspection on the parts, and compares the roughness and surface quality of the workpiece before and after processing. The inspection results of the morphology verified the feasibility and effectiveness of the processing method.

Contents of the invention

The purpose of the present invention is to provide an experimental verification method for abrasive flow processing of a servo valve spool nozzle, so as to better realize the experimental verification of abrasive flow processing and improve the use effect.

In order to achieve the above object, the technical solution of the present invention is as follows.

An experimental verification method for abrasive flow processing of servo valve spool nozzles. The abrasive flow processing technology is used to polish the inner surface of the micro-aperture channel of the servo valve spool nozzle. After the experiment, in order to detect the inner surface of the channel Firstly, the processed workpiece needs to be wire-cut, and after the parts are cleaned, the surface roughness of the inner surface of the workpiece, the surface morphology and the elemental composition of the workpiece are detected by corresponding testing instruments, which specifically include the following aspects and steps:

(1) Experimental workpiece: mainly to verify the effectiveness and feasibility of abrasive flow processing, it is necessary to use various detection methods to obtain the detection data of the inner surface of the nozzle, and observe the quality of the inner surface of the processing channel. Because the internal channel of the servo valve spool nozzle is narrow and slender, especially the small hole area of the nozzle, it is necessary to use a wire cutting machine tool to cut the section of the part after the experimental processing is completed, and then the cut part can be used in various environments. Surface detection; through the analysis of the local enlarged image, it is found that the inner surface of the nozzle part before processing is rough and not smooth, especially in the small hole area of the nozzle. improve. In order to better compare and analyze the quality of the inner surface of the nozzle before and after processing, the present invention uses different detection methods to detect the inner surface of the nozzle: use a high-power microscope to detect the small hole area of the nozzle; use NT1100 grating surface roughness measurement The surface roughness of the processed surface is detected by the instrument; the surface morphology of the processed surface and the component analysis of the processed surface are detected by the JOELJXA-840 electron probe microanalyzer.

(2) Analysis of detection results under a high-power microscope:

The use of NikonSMZ745T is mainly aimed at the surface measurement of the small hole area of the servo valve spool nozzle. Under different magnification conditions, the forming appearance of the small hole area before and after the servo valve spool nozzle is observed, and the surface morphology of the small hole area is compared by observation. In this way, the processing effect of abrasive flow machining technology can be judged. From the image of the small hole of the unprocessed nozzle, it can be seen that the position of the small hole of the nozzle is uneven; from the image of the small hole of the processed nozzle, it can be seen that the position of the small hole of the nozzle is smooth and flat. By comparing and analyzing the appearance pictures of the small hole area of the nozzle before and after processing, it can be known that the abrasive flow processing technology can improve the burr phenomenon in the small hole area, and smooth the uneven surface to improve the inner surface of the tiny hole. Surface Quality. The detection of the small hole area of the nozzle under a high-power microscope can only observe the general appearance of the nozzle area, and cannot accurately analyze the processing effect of the abrasive flow processing technology, especially the processing effect on the inner surface of the nozzle channel. further testing it.

(3) Analysis of the detection results of surface roughness:

The present invention selects three test points on the inner surface of the experimental workpiece after wire cutting to measure respectively, and uses the software installed randomly with the NT1100 grating surface roughness measuring instrument to obtain the two-dimensional and three-dimensional topography diagrams and related data.

By comparing the test results of each test point, it is found that: at the first test point, the initial roughness value of the inner surface of the part is 743.93nm, and its roughness value becomes 571.64nm after abrasive flow polishing; At the test point, the initial roughness of the inner surface of the part is 823.07nm, and the roughness value becomes 735.24 after abrasive flow polishing; at the third test point, the initial roughness value of the inner surface of the part is 1.1um, After abrasive flow polishing, its roughness value becomes 721.09nm.

From the changes in the surface roughness values before and after nozzle processing in the above two-dimensional surface topography diagram, it can be seen that the surface roughness value of the inner surface of the part after polishing by abrasive flow processing technology becomes smaller; from the three-dimensional surface topography, it can be seen The red area on the surface of the part is obvious. The red area indicates that the surface roughness is large here, and the peak of the surface protrusion is large. The red area on the surface of the part after processing is reduced, indicating that the material on the processed surface will protrude after abrasive flow grinding. The surface material is removed, so its surface protrusion peaks are reduced. To sum up, after the abrasive flow processing technology, the processing surface of the servo valve spool nozzle is improved, the inner surface finish is better, and the surface roughness value meets the requirements of the parts.

(4) Analysis of detection results of surface topography:

(a) Verification analysis of surface quality:

The JXA-840 instrument produced by Japan Electronics Co., Ltd. is used to detect the surface morphology of the parts before and after processing. Select 4 points in the processing channel of the servo valve valve core nozzle, and use the JXA-840 instrument to measure the microscopic morphology of the processed surface by 1000 times. Observe under 2000 times.

By observing the surface topography of the inner surface of the servo valve valve core nozzle under the condition of 1000 times magnification of the JXA-840 instrument, it is found by comparison that the inner surface topography of the polished part changes. The inner surface of the unprocessed nozzle parts is under the traditional processing state. The inner surface of the nozzle is rough, with undulating peaks and valleys, and unevenness. Although the surface texture is not particularly disordered, the surface has scratches of different shades and a certain number of Inclusion of debris; the appearance of the surface after abrasive flow polishing and grinding, the abrasive medium realizes the removal of the processed surface material by means of micro-grinding, the texture of the inner surface after processing is clear, smooth and dense, and the original scratches disappear , the surface quality is improved. In summary, the abrasive flow machining technology realizes the smoothing of the machined surface by means of abrasive media micro-grinding, obtains good surface roughness, and improves the surface quality of the inner surface of the nozzle.

(2) Prediction verification analysis of small hole area:

The wear amount of particles on each processing area is different due to the influence of the size of the model and the properties of the continuous phase and the discrete phase in the flow field. Compared with other parts, the wear amount of the small hole area is larger, so the prediction of abrasive flow processing The processing effect of the technology in the small hole area is better than other parts. Through comparison, it is found that the processing quality of the small hole area is not particularly good by the traditional process, mainly because the size of the small hole is too small, and the traditional process cannot finish the small hole. After abrasive finishing, both the inner surface of the main channel of the nozzle and the surface of the small hole area of the nozzle are improved; by comparing the surface topography of the main channel and the small hole area, the surface topography of the small hole of the valve core nozzle is compared The smoothness of the main channel is due to the difference in flow field turbulence and particle wear rate caused by the difference in size between the nozzle and the main channel, so the abrasive particle flow processing effect at each position of the part is different. Machining predictions for hole regions are consistent.

The beneficial effect of the invention lies in that the invention takes the servo valve valve core nozzle as the experimental processing part, and studies the surface quality of the part before and after processing. The present invention uses a variety of detection means to detect the inner surface of the part, respectively adopts a high-power microscope, NT1100 grating surface roughness and JEOLJXA-840 detection instrument, observes and analyzes the surface roughness and surface shape of each position point on the inner surface of the nozzle before and after processing. In order to demonstrate the effectiveness of abrasive flow processing technology, the micro-wear mechanism of abrasive media and the demonstration of processing prediction.

Description of drawings

Fig. 1 is a schematic diagram of the sample structure used in the embodiment of the present invention.

Fig. 2 is a scanning electron microscope view of an unprocessed nozzle hole in an embodiment of the present invention.

Fig. 3 is a scanning electron microscope view of the processed nozzle hole in the embodiment of the present invention.

detailed description

Specific embodiments of the present invention will be described below in conjunction with the accompanying drawings, so as to better understand the present invention.

Example

Instrument preparation for experimental processing:

(1) Abrasive flow processing experimental equipment:

The abrasive flow processing device mainly includes hydraulic cylinders, power systems, abrasive cylinders, fixtures, processing experiment bases and other processing accessories. Among them, a small hydraulic station using a three-phase asynchronous motor provides power for the experimental processing. The diameter of the abrasive cylinder and hydraulic cylinder is 100mm, and the fixture is set according to the structure and size of the workpiece to be processed.

(2) Wire cutting machine:

After the experimental processing, in order to detect the inner surface of the experimental processing, before the workpiece is inspected, it is necessary to use a wire cutting machine tool to cut the workpiece. The cutting accuracy range is -0.002mm～+0.002mm, and the processing range is 550*350*270.

(3) High power microscope:

The Nikon SMZ745T microscope is used, and its total magnification range is 3.35-300. By changing its magnification and combining with the SUNJOYSH200 video inspection system, it is possible to magnify and observe each tiny part of the part and observe its surface morphology.

(4) Surface roughness testing instrument:

Use the model NT1100 grating surface roughness measuring instrument to detect the surface roughness of the inner surface of the channel before and after workpiece processing. The NT1100 grating surface roughness measuring instrument can present a three-dimensional measurement map of the surface roughness through the measurement of the processed surface. The measurement range is from Sub-nanometer roughness to millimeter-level roughness, its detection is fast, with high resolution and high repeatability, which ensures the accuracy of the surface roughness measurement of the workpiece.

(5) Electron probe microanalyzer:

In order to better observe the processing effect of the inner surface before and after processing, when the processing is completed, it is necessary to use an electronic scanning electron microscope to detect and observe the processed surface of the workpiece. The experiment adopts the JEOL JXA-840 electron probe microanalyzer produced by JEOL, which can be used to detect the qualitative or quantitative analysis of the chemical composition of the material and the detection of the tissue morphology.

Materials for abrasive flow processing: Servo valve spool nozzles are used as the research object. Under room temperature conditions, self-developed grinding liquid is used for processing experiments on the nozzles. The carrier fluid of the grinding liquid is aviation hydraulic oil, and the solid particles are carbonized. silicon particles.

Artifact requirements:

The nozzle is an important part of the pre-stage of the spool of the servo valve. It can form a variable orifice with the baffle structure, and can realize the displacement control of the spool. The nozzle is a small precision rotary part, the size of the outer circle is divided into and Two types, the inner hole size is and Two types, jet orifice diameter is The length of the small hole is 0.3-0.5mm, the total length is 6-20mm, and the nozzle has high dimensional accuracy, shape accuracy and surface roughness. Its structural diagram is shown in Figure 1.

The nozzle requires that under a certain pressure condition, the nozzle hole within the range of 70mm will form a columnar jet without defects such as scattering, oblique shooting, and spiral, and the flow difference of the nozzles used in pairs should be controlled within ±2%. . This determines that the consistency of the small hole size, the removal of tiny burrs in the hole, the roughness and roundness of the inner hole must meet high requirements.

The materials of nozzle parts are difficult to process. Nowadays, the precision lathe drilling and reaming method is mainly used to process the small holes of nozzles. However, due to the small diameter of small holes, the materials are difficult to process, and the requirements for small hole size and shape and position tolerance are high. Processing It is not easy to guarantee; the burr at the intersection of the small jet hole and the oil hole is difficult to remove cleanly, and it is easy to cause the nozzle jet to scatter and spiral; and the size of the small hole and the oil hole are too small, there is no suitable tool to remove the burr at the intersection. To sum up, the processing pass rate of small nozzle holes is low, and the processing efficiency is low. According to the processing characteristics of abrasive flow processing technology, the problems in nozzle processing can be improved.

Experimental grinding fluid:

This experimental processing uses self-developed grinding fluid, the carrier fluid is aviation hydraulic oil, and the solid particles are silicon carbide particles. According to the size of the workpiece and the processing conditions, a reasonable particle diameter is selected and configured according to a certain ratio.

Experimental Results and Discussion:

This experiment mainly uses abrasive flow processing technology to polish the inner surface of the micro-aperture channel of the servo valve valve core nozzle. Afterwards, the surface roughness of the inner surface of the workpiece as well as the surface morphology and the elemental composition of the workpiece are detected by corresponding testing instruments.

(1) Experimental workpiece

To verify the effectiveness and feasibility of abrasive flow machining, it is necessary to use various detection methods to obtain the detection data of the inner surface of the nozzle and observe the quality of the inner surface of the processing channel. Because the internal channel of the servo valve spool nozzle is narrow and slender, especially the small hole area of the nozzle, it is necessary to use a wire cutting machine tool to cut the section of the part after the experimental processing is completed, and then the cut part can be used in various environments. Surface detection.

Through the analysis of the partial enlarged picture, it is found that the inner surface of the nozzle parts before processing is rough and not smooth, especially in the area of the small hole of the nozzle. In order to better compare and analyze the quality of the inner surface of the nozzle before and after processing, the present invention uses different detection methods to detect the inner surface of the nozzle: use a high-power microscope to detect the small hole area of the nozzle; use NT1100 grating surface roughness measurement The surface roughness of the processed surface is detected by the instrument; the surface morphology of the processed surface and the component analysis of the processed surface are detected by the JOELJXA-840 electron probe microanalyzer.

(2) Analysis of detection results under a high-power microscope:

The use of NikonSMZ745T is mainly aimed at the surface measurement of the small hole area of the servo valve spool nozzle. Under different magnification conditions, the forming appearance of the small hole area before and after the servo valve spool nozzle is observed, and the surface morphology of the small hole area is compared by observation. In this way, the processing effect of abrasive flow machining technology can be judged. Because of the large amount of experimental data, it is impossible to discuss them one by one. Here, only one set of measurement results before the small nozzle hole machining and two sets of measurement results after the nozzle small hole machining are selected. The detection results of the nozzle small hole area are shown in Figure 2 , as shown in Figure 3.

From the image of the small hole of the unprocessed nozzle, it can be seen that the position of the small hole of the nozzle is uneven; from the image of the small hole of the processed nozzle, it can be seen that the position of the small hole of the nozzle is smooth and flat. By comparing and analyzing the appearance pictures of the small hole area of the nozzle before and after processing, it can be known that the abrasive flow processing technology can improve the burr phenomenon in the small hole area, and smooth the uneven surface to improve the inner surface of the tiny hole. Surface Quality.

The detection of the small hole area of the nozzle under a high-power microscope can only observe the general appearance of the nozzle area, and cannot accurately analyze the processing effect of the abrasive flow processing technology, especially the processing effect on the inner surface of the nozzle channel. further testing it.

(3) Analysis of the detection results of surface roughness:

The present invention selects three test points on the inner surface of the experimental workpiece after wire cutting to measure respectively, and uses the software installed randomly with the NT1100 grating surface roughness measuring instrument to obtain the two-dimensional and three-dimensional topography diagrams and related data.

By comparing the test results of each test point, it is found that: at the first test point, the initial roughness value of the inner surface of the part is 743.93nm, and its roughness value becomes 571.64nm after abrasive flow polishing; At the test point, the initial roughness of the inner surface of the part is 823.07nm, and the roughness value becomes 735.24 after abrasive flow polishing; at the third test point, the initial roughness value of the inner surface of the part is 1.1um, After abrasive flow polishing, its roughness value becomes 721.09nm.

From the changes in the surface roughness values before and after nozzle processing in the above two-dimensional surface topography diagram, it can be seen that the surface roughness value of the inner surface of the part after polishing by abrasive flow processing technology becomes smaller; from the three-dimensional surface topography, it can be seen The red area on the surface of the part is obvious. The red area indicates that the surface roughness is large here, and the peak of the surface protrusion is large. The red area on the surface of the part after processing is reduced, indicating that the material on the processed surface will protrude after abrasive flow grinding. The surface material is removed, so its surface protrusion peaks are reduced. To sum up, after the abrasive flow processing technology, the processing surface of the servo valve spool nozzle is improved, the inner surface finish is better, and the surface roughness value meets the requirements of the parts.

(4) Analysis of detection results of surface topography:

(a) Verification analysis of surface quality

The JXA-840 instrument produced by Japan Electronics Co., Ltd. is used to detect the surface morphology of the parts before and after processing. Select 4 points in the processing channel of the servo valve valve core nozzle, and use the JXA-840 instrument to measure the microscopic morphology of the processed surface by 1000 times. Observe under 2000 times.

By observing the surface topography of the inner surface of the servo valve valve core nozzle under the condition of 1000 times magnification of the JXA-840 instrument, it is found by comparison that the inner surface topography of the polished part changes. The inner surface of the unprocessed nozzle parts is under the traditional processing state. The inner surface of the nozzle is rough, with undulating peaks and valleys, and unevenness. Although the surface texture is not particularly disordered, the surface has scratches of different shades and a certain number of Inclusion of debris; the appearance of the surface after abrasive flow polishing and grinding, the abrasive medium realizes the removal of the processed surface material by means of micro-grinding, the texture of the inner surface after processing is clear, smooth and dense, and the original scratches disappear , the surface quality is improved. In summary, the abrasive flow machining technology realizes the smoothing of the machined surface by means of abrasive media micro-grinding, obtains good surface roughness, and improves the surface quality of the inner surface of the nozzle.

(2) Prediction verification analysis of small hole area:

The wear amount of particles on each processing area is different due to the influence of the size of the model and the properties of the continuous phase and the discrete phase in the flow field. Compared with other parts, the wear amount of the small hole area is larger, so the prediction of abrasive flow processing The processing effect of the technology in the small hole area is better than other parts. Through comparison, it is found that the processing quality of the small hole area is not particularly good by the traditional process, mainly because the size of the small hole is too small, and the traditional process cannot finish the small hole. After abrasive finishing, both the inner surface of the main channel of the nozzle and the surface of the small hole area of the nozzle are improved; by comparing the surface topography of the main channel and the small hole area, the surface topography of the small hole of the valve core nozzle is compared The smoothness of the main channel is due to the difference in flow field turbulence and particle wear rate caused by the difference in size between the nozzle and the main channel, so the abrasive particle flow processing effect at each position of the part is different. Machining predictions for hole regions are consistent.

The above description is a preferred embodiment of the present invention, and it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered Be the protection scope of the present invention.

Claims (1)

1. A method for verifying the abrasive flow processing experiment of a servo valve spool nozzle, characterized in that: the abrasive flow processing technology is used to polish the inner surface of the micro-aperture passage to the servo valve spool nozzle. After the experiment, in order to The detection of the inner surface of the channel first needs to cut the processed workpiece by wire, after cleaning the parts, and then use the corresponding detection equipment to detect the surface roughness of the inner surface of the workpiece, the surface morphology and the elemental composition of the workpiece, specifically including the following aspects and steps : (1) Experimental workpiece: After the experimental processing is completed, it is necessary to use a wire cutting machine tool to cut the cutting section of the part, and then the inner surface of the cut part can be tested in various environments; The inner surface of the nozzle part is rough and not smooth, especially in the small hole area of the nozzle. The inner surface of the processed nozzle is somewhat improved, whether in the processing channel or the small hole area of the nozzle; in order to better compare and analyze the inner surface of the nozzle before and after processing quality, the present invention adopts different detection means to detect the inner surface of its processing: use a high-power microscope to detect the small hole area of the nozzle; use the NT1100 grating surface roughness measuring instrument to detect the surface roughness of the processed surface; use JOELJXA-840 Electron probe microanalyzer detects the surface morphology of the processed surface and analyzes the composition of the processed surface; (2) Analysis of detection results under a high-power microscope: The use of NikonSMZ745T is mainly aimed at the surface measurement of the small hole area of the servo valve spool nozzle. Under different magnification conditions, the forming appearance of the small hole area before and after the servo valve spool nozzle is observed, and the surface morphology of the small hole area is compared by observation. In this way, the processing effect of abrasive flow processing technology can be judged; (3) Analysis of the detection results of surface roughness: Three test points were selected to measure the inner surface of the experimental workpiece after wire cutting, and the two-dimensional and three-dimensional topography and related data of the workpiece surface roughness were obtained by using the software installed with the NT1100 grating surface roughness measuring instrument; (4) Analysis of detection results of surface topography: (a) Verification analysis of surface quality: The JXA-840 instrument produced by Japan Electronics Co., Ltd. is used to detect the surface morphology of the parts before and after processing. Select 4 points in the processing channel of the servo valve valve core nozzle, and use the JXA-840 instrument to measure the microscopic morphology of the processed surface by 1000 times. Observation under 2000 times; (2) Prediction verification analysis of small hole area: The wear amount of particles on each processing area is different due to the influence of the size of the model and the properties of the continuous phase and the discrete phase in the flow field. Compared with other parts, the wear amount of the small hole area is larger, so the prediction of abrasive flow processing The processing effect of the technology in the small hole area is better than other parts; through comparison, it is found that the processing quality of the small hole area by the traditional process is not particularly good, mainly because the size of the small hole is too small, and the traditional process cannot be processed on the small hole. Finishing; After abrasive flow finishing, both the inner surface of the nozzle main channel and the surface of the small hole area of the nozzle are improved; by comparing the surface topography of the main channel and the small hole area, the surface of the small hole of the valve core nozzle is shown The shape is smoother and flatter than that of the main channel. This is due to the difference in flow field turbulence and particle wear rate caused by the size difference between the nozzle part and the main channel. The processing predictions in the small hole area are consistent.