Mechanical seal bevel groove laser processing method based on block variable distance filling technology

Abstract

This invention discloses a laser processing method for inclined bottom grooves in mechanical seals based on segmented variable-pitch filling technology. The method includes the following steps: First, the inclined bottom groove graphic is drawn using AutoCAD software and segmented into multiple sub-regions; second, variable-pitch filling is performed on each sub-region to obtain the inclined bottom groove processing graphic; finally, the inclined bottom groove processing graphic is imported, the test piece is clamped, focusing is performed, and process parameters are set to complete the inclined bottom groove processing. This method can realize the processing of inclined bottom grooves in mechanical seals; it is simple and highly feasible.

Description

Technical Field

[0001] This invention relates to a laser processing method for inclined bottom grooves of mechanical seals based on segmented variable pitch filling technology, belonging to the field of laser precision machining technology for mechanical seals. Background Technology

[0002] Hydrodynamic mechanical seals are a type of non-contact mechanical seal. They achieve non-contact operation by creating multiple micron-sized hydrodynamic grooves on the sealing end face, utilizing the hydrodynamic effect to generate an extremely thin fluid film between the sealing ring end faces, thus improving lubrication between the sealing end faces. Compared to ordinary contact mechanical seals, they have advantages such as lower leakage, longer service life, and more stable operation, and are widely used in industries such as petroleum and chemical engineering.

[0003] The core technology of hydrodynamic mechanical seals is how to machine micron-level hydrodynamic grooves on the end face of the sealing ring. Generally, based on the shape of the end face, hydrodynamic grooves can be classified into spiral grooves, T-grooves, arc grooves, and complex grooves combining various shapes. Based on the cross-sectional shape, they can be classified into grooves of equal depth (also known as flat-bottomed grooves) and grooves of unequal depth. Currently, spiral grooves and T-grooves commonly used in the dry gas sealing field are generally of equal depth, while sloping-bottomed grooves are a type of unequal-depth groove. The difference between sloping-bottomed and flat-bottomed grooves lies only in their cross-sectional shape; the groove depth is conical or divergent, while the end face shape can still adopt spiral, T-grooves, arc grooves, etc. Peng Jian pointed out through theoretical research that sloping-bottomed spiral grooves have superior performance compared to flat-bottomed spiral grooves, but their machining difficulty is significantly higher. This is because the depth of flat-bottomed grooves is uniform, and it is relatively easy to process flat-bottomed grooves using existing laser processing technology. However, the depth of grooves on the cross-section of inclined-bottomed grooves is not uniform. Using the laser processing technology for flat-bottomed grooves, it is difficult to control the different groove depths of each cross-section, so it cannot meet the design requirements of inclined-bottomed grooves. To date, there are few reports on experimental research results on the processing of inclined-bottomed grooves. Summary of the Invention

[0004] To address the above problems, this invention aims to provide a laser processing method for inclined bottom grooves in mechanical seals based on segmented variable-pitch filling technology. This invention divides the inclined bottom groove pattern into multiple sub-regions along the direction from the deepest to the shallowest side. Then, by using gradually increasing filling spacing, each sub-region is filled sequentially. This allows the groove depth to gradually decrease from the deepest to the shallowest side after processing, thus meeting the design requirements of the inclined bottom groove and enabling the processing of inclined bottom grooves using laser technology.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] (1) Draw the sloping bottom groove graphic using AutoCAD software based on the end face geometric parameters of the sloping bottom groove;

[0007] (2) Based on the cross-sectional geometric parameters of the sloping bottom channel, the sloping bottom channel is divided into several sub-regions along the direction from the deepest side to the shallowest side.

[0008] (3) Perform variable-pitch filling on each sub-region to obtain the sloping bottom groove processing pattern;

[0009] (4) Import the slanted bottom groove processing graphic, clamp the test piece, adjust the focus and set the process parameters, and use a fiber laser marking machine to complete the slanted bottom groove processing.

[0010] Preferably, the number of sloping bottom grooves is 2 to 40.

[0011] Preferably, the geometric parameters of the inclined bottom groove section include the deepest side groove depth. h g1 and the shallowest side groove depth h g2 The groove depths are all 1~500μm.

[0012] Preferably, the block processing refers to dividing the graphic into several sub-regions along the direction from the deepest side to the shallowest side of the inclined bottom channel according to the cross-sectional geometric parameters of the inclined bottom channel. The number of sub-regions is the number of blocks, and the number of blocks is 1 to 500.

[0013] Preferably, the segmented variable spacing filling refers to selecting different filling spacings to fill the sloping bottom groove pattern sequentially according to the target groove depth of each sub-region. The deeper the groove of the sub-region, the smaller the filling spacing is used, with a filling spacing of 1~100μm.

[0014] Preferably, the test specimen material is not limited, including silicon carbide, tungsten carbide, stainless steel, etc., and the process parameters are laser power 1~100W, repetition frequency 1~100kHz, scanning speed 1~10000mm / s, and marking times 1~100 times.

[0015] Preferably, the shape of the end face of the inclined bottom groove is not limited, including rectangular, triangular, spiral, T-shaped, U-shaped, herringbone, straight, arc-shaped, etc.

[0016] Preferably, the sloping bottom groove can be replaced by any type of groove with unequal depth (stepped groove, curved groove, etc.).

[0017] Preferably, all of the grooves can be replaced by microcavities.

[0018] Advantages of the present invention: The laser processing method for inclined bottom groove of mechanical seal based on block variable pitch filling technology proposed in this invention can realize the processing of inclined bottom groove, solve the problem of high processing difficulty of inclined bottom groove in the mechanical seal industry, and has the advantages of simple method and strong feasibility.

[0019] The beneficial effects of this invention are that it can be applied not only to the laser processing of inclined bottom grooves for mechanical seals, but also to the processing of various grooves or micro-cavities of unequal depths, such as stepped grooves and curved surface grooves, in the field of mechanical seals. It can also provide reference and guidance for the laser processing of various grooves or micro-cavities of unequal depths in other industries. Attached Figure Description

[0020] Figure 1 This is a flowchart of the present invention.

[0021] Figure 2 This is a schematic diagram of the cross-sectional shape of the inclined bottom groove.

[0022] Figure 3 This is a schematic diagram of the segmented variable-distance filling of the sloping bottom groove.

[0023] Figure 4 This is a comparison image of the actual bottom morphology of the sloping bottom channel and the ideal bottom morphology. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1: First, based on the end face geometry parameters of the sloping bottom groove, the sloping bottom groove graphic is drawn using AutoCAD software and formed into a closed surface region. Second, based on the cross-sectional geometry parameters of the sloping bottom groove, the sloping bottom groove graphic is divided into multiple sub-regions along the direction from the deepest side to the shallowest side. The number of sub-regions depends on the length of the sloping bottom groove along the direction from the deepest side to the shallowest side; the longer the length, the more sub-regions there are. Then, using the fill function of AutoCAD, each sub-region is filled sequentially with gradually increasing fill spacing, and the filled sloping bottom groove processing graphic is saved as a PLT format. Finally, the PLT format sloping bottom groove processing graphic is imported into the marking machine software. The specimen is clamped and fixed, and the height of the laser lifting platform is adjusted to focus the laser spot on the specimen surface. Process parameters such as laser power, repetition frequency, scanning speed, and marking times are set. The sloping bottom groove is processed and the groove depth is measured using a fiber laser marking machine and a surface roughness profile shape measuring machine, respectively. If the groove depth of the sloping bottom groove cross section does not meet the design requirements, the filling spacing of each area needs to be adjusted according to the deviation between the actual groove depth and the target groove depth of each sub-area. The sloping bottom groove processing and groove depth measurement process is repeated until the groove depth of the sloping bottom groove cross section meets the design requirements.

[0026] Example 2: The inclined bottom groove is rectangular in shape, with dimensions of 3×12mm. A schematic diagram of the cross-sectional shape of the inclined bottom groove is shown below. Figure 2 As shown. The left side of the rectangular groove is the deepest side, and the deepest side groove depth is... h g1 The depth is 20 μm. The right side is the shallowest side of the trench. The shallowest side trench depth is... h g2The depth is 10 μm, and the depth of the rectangular groove decreases linearly from the leftmost to the rightmost side.

[0027] Using AutoCAD software, a 3×12mm rectangle was drawn and evenly divided into 6 sub-regions along the length of the groove. Then, from left to right, the fill spacing was gradually increased to fill each sub-region with variable spacing. A schematic diagram of the variable spacing filling of the sloping bottom groove is shown below. Figure 3 As shown in Table 1, the fill spacing used in each sub-region is as follows.

[0028] Table 1 Fill Spacing of Each Sub-region

[0029] subregion 1 2 3 4 5 6 Fill spacing / μm 8 9 10 11 13 16

[0030] Save the segmented and filled inclined groove processing pattern in PLT format and import it into the marking machine software. Then, clamp and fix the specimen on the processing worktable. The specimen material is silicon carbide (SiC). Adjust the laser lifting platform so that the focused spot is on the surface of the sealing ring. Set the process parameters: laser power 9.61W, scanning speed 495.16mm / s, repetition frequency 30kHz, and marking times 3 times.

[0031] The sloping bottom groove was processed using an LM-20 fiber laser marking machine, and then the groove depth of different areas of the sloping bottom groove was measured using a SEF-680 surface roughness profile shape measuring machine.

[0032] Figure 4 The image shows a comparison between the actual and ideal bottom morphology of the sloping-bottom groove. As can be seen, the groove depth gradually decreases from left to right. When the number of blocks is 6, the actual bottom morphology of the sloping-bottom groove is stepped, which closely matches the ideal conical bottom morphology, indicating the feasibility of the method proposed in this invention. In actual processing, the number of blocks can be further increased, dividing the sloping-bottom groove pattern into more sub-regions, which can effectively improve the processing accuracy of the bottom morphology of the sloping-bottom groove, making the actual cross-sectional shape of the sloping-bottom groove closer to the ideal conical shape.

[0033] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A mechanical seal chamfering method based on a block variable distance filling technique, characterized in that, The method comprises the following steps: (1) drawing a graph of the inclined bottom groove according to the end face geometric parameters of the inclined bottom groove by using AutoCAD software; (2) according to the cross section geometric parameters of the inclined bottom groove, the graph of the inclined bottom groove is divided into several sub-regions along the direction from the deepest side to the shallowest side of the inclined bottom groove; (3) each sub-region is filled with variable distance to obtain the processing graph of the inclined bottom groove; specifically, the filling function of AutoCAD is used to fill each sub-region with gradually increasing filling distance, and the filled processing graph of the inclined bottom groove is saved in PLT format; the variable distance filling refers to filling the graph of the inclined bottom groove with different filling distances according to the target groove depth of each sub-region; the smaller the filling distance is, the deeper the groove depth of the sub-region is; the filling distance is 1-100 μm; (4) the PLT format processing graph of the inclined bottom groove is imported into the marking machine software, the test piece is clamped and fixed, the height of the laser lifter is adjusted to focus the laser spot on the surface of the test piece, the process parameters of laser power, repetition frequency, scanning speed, marking times are set, and the inclined bottom groove is processed.

2. The mechanical seal bevel groove laser processing method based on the block variable distance filling technique according to claim 1, characterized in that: The number of the inclined bottom grooves is 2-40.

3. The mechanical seal bevel groove laser processing method based on the block variable distance filling technique according to claim 1, characterized in that: The cross-sectional geometric parameters of the inclined bottom groove include a deepest side groove depth h g1 and a shallowest side groove depth h g2 , each of the groove depths being 1-500 μm; the block processing refers to dividing a graph into a plurality of sub-regions according to the cross-sectional geometric parameters of the inclined bottom groove from the deepest side to the shallowest side of the inclined bottom groove, the number of the sub-regions being the number of blocks, the number of blocks being 1-500.

4. The mechanical seal bevel groove laser processing method based on the block variable-pitch filling technique according to claim 1, characterized in that: The process parameters are as follows: laser power is 1-100 W, repetition frequency is 1-100 kHz, scanning speed is 1-10000 mm / s, and marking times are 1-100.

5. The mechanical seal bevel groove laser processing method based on the block variable distance filling technique according to claim 1, characterized in that: The end face shape of the inclined bottom groove is any one or more of the following shapes: rectangle, triangle, spiral, T shape, U shape, herringbone shape, straight line shape and circular arc shape.

6. The mechanical seal bevel groove laser processing method based on the block variable-pitch filling technique according to claim 1, characterized in that: The inclined bottom groove can be replaced by any non-equal-depth groove.

7. The mechanical seal bevel groove laser processing method based on the block variable-pitch filling technique according to claim 1, characterized in that: The inclined bottom groove can be replaced by a micro-cavity.

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