A water-based abrasive flow polishing complex hole structure processing time prediction method

Abstract

The application discloses a water-based abrasive flow polishing complex hole structure processing time prediction method, characterized in that the relationship among processing parameters, roughness, hole wall dynamic pressure and processing time is obtained through a straight hole orthogonal test of materials with same parameters and dynamic pressure simulation, and then the processing time of the maximum baseline surface in the inclined hole is obtained through a simulation software as the processing prediction time of the complex part inclined hole. The application can effectively predict the polishing time of the complex inclined hole, and does not need to repeatedly test and process, thereby saving time and economic cost.

Description

Technical Field

[0001] This invention pertains to micro-hole finishing technology, particularly a finishing technology for water-based abrasive flow polishing of complex oblique hole structures, specifically a method for predicting the processing time of water-based abrasive flow polishing of complex oblique hole structures. Background Technology

[0002] Complex oblique hole structures are widely used in aerospace and other fields, serving important functions such as transporting media and dissipating heat. A typical example of a complex oblique hole structure is the film cooling hole in turbine blades, characterized by a large number of micro-holes with varying diameters and angles. Parts with complex oblique hole structures are often made of difficult-to-machine metal materials, and the oblique holes are mostly machined using thermal processes such as electrical discharge machining and laser processing. The machined surface may have a recast layer and micro-cracks, requiring polishing of the hole walls to meet surface quality requirements.

[0003] Water-based abrasive flow has advantages such as good fluidity, good accessibility, and ease of subsequent cleaning, making it a promising candidate for polishing complex inclined hole structures. However, the variations in pore diameter and angle within complex inclined hole structures lead to uneven dynamic pressure on the hole wall surface at different diameters and angles when the water-based abrasive working fluid flows to each target hole. This results in differences in polishing results at different locations within the hole, making it difficult to determine appropriate polishing parameters and process time.

[0004] If the method of dissecting and inspecting each target hole in a complex oblique hole structure one by one, and then repeatedly iterating through polishing experiments to obtain polishing parameters, the workload and cost would be enormous. In fact, the main factor affecting the water-based abrasive flow polishing effect inside the oblique hole is the dynamic pressure of the solid abrasive particles on the hole wall. For vertical holes, because the flow direction of the abrasive working fluid entering the hole is consistent with the hole axis, the dynamic pressure distribution of the abrasive particles inside the hole is relatively uniform. For oblique holes, because the flow direction of the abrasive working fluid entering the hole is at a certain angle to the hole axis, the dynamic pressure distribution inside the oblique hole is uneven. At locations with higher abrasive dynamic pressure values, the material removal rate of the hole wall polishing is higher, and vice versa. Therefore, the processing time for water-based abrasive flow polishing of complex oblique holes can be estimated by combining the oblique hole abrasive dynamic pressure distribution with the results of straight hole polishing. Summary of the Invention

[0005] The purpose of this invention is to address the problem of uneven polishing effect of water-based abrasive flow inside complex inclined holes, which makes it difficult to reasonably determine the polishing time. This invention provides a method for predicting the processing time of complex inclined hole structures by water-based abrasive flow polishing. It can effectively predict the polishing time of complex inclined holes, avoids the process of dissecting and inspecting each target hole of the complex inclined hole structure one by one and iterative experiments, and improves the polishing efficiency of complex inclined holes.

[0006] The technical solution of this invention is:

[0007] A method for predicting the processing time of complex oblique hole structures by water-based abrasive flow polishing, characterized by comprising the following steps:

[0008] Step 1: Determine the adjustment range of water-based abrasive flow polishing processing parameters, including but not limited to: abrasive size m, abrasive concentration A, liquid supply pressure P1, polishing time t, and abrasive type garnet;

[0009] Step 2: Determine the workpiece material M, and fabricate a batch of straight holes H with fixed dimensions based on the workpiece material; design an orthogonal experiment for polishing the straight holes H based on the polishing parameters range in Step 1, and obtain N sets of orthogonal experimental parameters; implement the orthogonal experiment and obtain N experimental results.

[0010] Step 3: Detect the N test results described in Step 2 to obtain the surface roughness values ​​Ra of the N holes;

[0011] Step 4: Using CFD simulation software, based on the orthogonal polishing test conditions described in Step 2, simulate and calculate the abrasive dynamic pressure P2 inside the straight hole H under the N sets of parameters in the orthogonal test table;

[0012] Step 5: Based on the N polishing test roughness values ​​obtained in Step 3 and the abrasive dynamic pressure values ​​calculated in Step 4, an empirical model of the internal surface roughness of the straight hole with respect to polishing parameters and abrasive dynamic pressure is established using regression analysis.

[0013]

[0014] Where c and k i (i = 1, 2, 3, 4, 5) are the coefficients obtained by regression analysis.

[0015] Step 6: Use formula (1) to inversely calculate the prediction model for polishing time t. The specific formula is as follows:

[0016]

[0017] Step 7: For multi-slanted hole parts made of material M, determine the polishing parameters: abrasive size m, abrasive concentration A, liquid supply pressure P1, and set the expected polishing surface roughness value Ra; based on the polishing parameters, calculate the abrasive dynamic pressure distribution inside each hole using CFD simulation software.

[0018] Step 8: For each target hole on a multi-slanted hole part, extract the abrasive dynamic pressure distribution data of the hole wall. Specifically, for each target hole, divide it into four equal parts along the major and minor axes, and take four lines along the axis as sampling positions to obtain the abrasive dynamic pressure distribution curve data. This step can be efficiently implemented through secondary application development of CFD software.

[0019] Step 9: Based on the required surface roughness Ra of the hole wall, using the empirical model obtained in Step 6, calculate the polishing time required to achieve Ra at the four line positions within each oblique hole, and take the maximum value as the polishing time for a single oblique hole. Finally, take the longest polishing time for all oblique holes as the overall polishing time.

[0020] The beneficial effects of this invention are:

[0021] This invention addresses the challenge of predicting processing time when performing complex oblique hole finishing on a specific material (difficult-to-machine material) using water-based abrasive flow. It utilizes simple straight hole finishing experiments and dynamic pressure simulations, storing the results for future reference and establishing a processing time prediction model. For subsequent complex oblique hole structures made from the same material, this model can be invoked, and the simulation results can be combined to predict the processing time, eliminating the need for repeated experimental processing and saving time and economic costs. Attached Figure Description

[0022] Figure 1 This is a flowchart of the processing time prediction method of the present invention.

[0023] Figure 2 This is a schematic diagram of the vertical hole for water-based abrasive flow polishing according to the present invention.

[0024] Figure 3 This is a schematic diagram of a complex oblique hole structure with multiple different diameters and angles as described in this invention.

[0025] Figure 4 This is a schematic diagram of the complex oblique hole polishing process using water-based abrasive flow as described in this invention.

[0026] Figure 5 This is a schematic diagram of the sampling positions of the four dynamic pressure distribution lines of the single oblique hole described in this invention.

[0027] Figure 6 This is a trend diagram of the four dynamic pressure distribution lines of the single oblique hole described in this invention.

[0028] Figure 7 This is a prediction diagram of the polishing processing time for the single oblique hole described in this invention.

[0029] In the figure: 1. Fluid inflow, 2. High-speed water flow, 3. Metal matrix, 4. Abrasive particles, 5. Fluid outflow, 6. Sampling position A, 7. Sampling position B, 8. Sampling position C, 9. Sampling position D, 10. Predicted polishing time for a single oblique hole. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] like Figure 1As shown.

[0032] A method for predicting the processing time of complex oblique hole structures by water-based abrasive flow polishing includes the following steps:

[0033] Step 1: Determine the adjustment range of water-based abrasive flow polishing processing parameters. Select abrasive particle size m from 2000 mesh to 800 mesh. Set the liquid supply pressure P1 to 3-5 MPa. Select abrasive concentration A from 1-2 wt%. Set the polishing time t to 15-45 s. Use garnet abrasive and keep the abrasive working fluid at room temperature.

[0034] Step 2: Select a sample made of GH4169 high-temperature alloy, with dimensions of 40mm×40mm×4mm. Divide it into two samples of 40mm×20mm×4mm each using laser cutting. Perform electrical discharge machining (EDM) along the cutting line to obtain a straight hole H with a diameter of 0.5mm. Based on the polishing parameters from Step 1, design an orthogonal experiment for polishing the straight hole H. The experiment design has 3 levels, according to the orthogonal experimental table L9(3 4 The experiment was conducted, and the polishing process diagram is shown below. Figure 2 As shown;

[0035] Step 3: Use a 3D profile measuring instrument to test the 9 sets of test results described in Step 2, and obtain the surface roughness values ​​Ra of the 9 holes.

[0036] Step 4: Using CFD simulation software, based on the orthogonal polishing test conditions described in Step 2, simulate and calculate the abrasive dynamic pressure P2 inside the straight hole H under the 9 sets of parameters in the orthogonal test table; for the straight hole, the abrasive dynamic pressure distribution on the hole wall is relatively uniform.

[0037] Step 5: Based on the 9 polishing test roughness values ​​obtained in Step 3 and the abrasive dynamic pressure values ​​calculated in Step 4, an empirical model of the internal surface roughness of the straight hole with respect to polishing parameters and abrasive dynamic pressure is established using regression analysis.

[0038]

[0039] Where c and k i (i = 1, 2, 3, 4, 5) are the coefficients obtained by regression analysis.

[0040] Step 6: Use formula (1) to inversely calculate the prediction model for polishing time t. The specific formula is as follows:

[0041]

[0042] Step 7: For multi-slanted hole parts made of GH4169 high-temperature alloy (such as...) Figure 3As shown in the diagram, the part contains four single oblique holes with different diameters and angles. The diameter ranges from 0.4 to 0.7 mm, and the angle ranges from 0 to 45°. For each oblique hole, the polishing parameters are determined as follows: abrasive size m = 1300 mesh, abrasive concentration A = 1 wt%, liquid supply pressure P1 = 5 MPa, and the expected polished surface roughness Ra is set to 3.2 μm. The polishing process diagram is shown in the diagram. Figure 4 As shown; based on the set polishing parameters, the dynamic pressure distribution of abrasive particles inside the target hole is calculated using CFD simulation software;

[0043] Step 8: Extract the abrasive dynamic pressure distribution data of all target hole walls. The specific method is as follows: For each target hole, divide the inclined hole into four equal parts along the major and minor axes, and take four lines along the axis as sampling positions. The sampling position diagram is shown below. Figure 5 As shown, the abrasive dynamic pressure distribution curve data were obtained (e.g.) Figure 6 (As shown).

[0044] Step 9: Based on the required surface roughness value Ra of the hole wall, calculate the polishing time required to reach Ra at the four line positions inside the target hole using the polishing time prediction model (shown in Step 6). Take the maximum value as the polishing time for a single oblique hole (e.g., Figure 7 (As shown). Finally, the longest polishing time for all the angled holes is taken as the overall polishing time.

[0045] The parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A method for predicting the processing time of complex oblique hole structures by water-based abrasive flow polishing, characterized in that, It includes the following steps: Step 1: Determine the adjustment range of water-based abrasive flow polishing processing parameters, including: abrasive size m, abrasive concentration A, liquid supply pressure P1, polishing time t, and abrasive type garnet; Step 2: Determine the workpiece material M, and fabricate a batch of straight holes H with fixed dimensions based on the workpiece material; design an orthogonal experiment for polishing the straight holes H based on the polishing parameters range in Step 1, and obtain N sets of orthogonal experimental parameters; implement the orthogonal experiment and obtain N experimental results. Step 3: Detect the N test results described in Step 2 to obtain the surface roughness values ​​Ra of the N straight holes H; Step 4: Using CFD simulation software, based on the orthogonal polishing test conditions in Step 2, simulate and calculate the abrasive dynamic pressure P2 inside the straight hole H under the N sets of parameters in the orthogonal test table; Step 5: Based on the surface roughness values ​​Ra of the N polishing tests obtained in Step 3, and the abrasive dynamic pressure values ​​calculated in Step 4, an empirical model of the surface roughness values ​​inside the straight hole with respect to polishing parameters and abrasive dynamic pressure is established using regression analysis. Among them, c and k i (i = 1, 2, 3, 4, 5) are the coefficients obtained by regression analysis. Step 6: Use formula (1) to inversely calculate the prediction model for polishing time t. The specific formula is as follows: Step 7: For multi-slanted hole parts made of material M, determine the polishing parameters: abrasive size m, abrasive concentration A, and liquid supply pressure P1, and set the expected polishing surface roughness value; based on the polishing parameters, calculate the abrasive dynamic pressure distribution inside each hole using CFD simulation software. Step 8: For each target hole on the multi-slanted hole part, extract the abrasive dynamic pressure distribution data of the target hole wall. The specific method is: for each target hole, divide the inclined hole into four equal parts along the long axis and short axis, take 4 lines along the axis as sampling positions, and obtain the abrasive dynamic pressure distribution curve data. Step 9: Based on the surface roughness requirement of the hole wall, substitute the value of Ra in the empirical model formula obtained in Step 6 into formula (2), calculate the polishing time required to achieve the corresponding surface roughness requirement at the four line positions in the target hole, and take the maximum value as the polishing time of a single oblique hole. Finally, the longest polishing time for all the angled holes is taken as the overall polishing time.

2. The method according to claim 1, characterized in that, Step 8: Achieve efficient operation through secondary application development of CFD software.

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