High-precision machining method for conical high-temperature alloy part based on 3D additive manufacturing

Abstract

The conical high-temperature alloy part high-precision machining method based on 3D additive manufacturing comprises the steps that a clamping boss is formed on the surface of a blank through additive manufacturing, and the blank is supported and clamped through the clamping boss by means of a machine tool; performing multi-point detection on the surface of the blank by adopting a machine tool measuring head to obtain actual surface point cloud data; fitting the actual surface point cloud data through a least square method to obtain a reference plane, and obtaining an actual measurement point cloud model according to the reference plane; according to a preset CAD theoretical model and an actual measurement point cloud model, obtaining a margin value of each measurement point; establishing a margin distribution model by adopting an inverse distance weighted interpolation algorithm according to the margin value of each measurement point; taking a preset theoretical layer thickness as a reference, obtaining a local machining layer thickness according to the allowance distribution model, and generating a self-adaptive tool path according to the local machining layer thickness; and the machine tool carries out machining according to the self-adaptive tool path. According to the method, the machining precision and efficiency can be improved while the wall thickness consistency of parts is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of numerical control machining, and particularly relates to a high-precision machining method for a conical high-temperature alloy part based on 3D additive manufacturing. BACKGROUND

[0002] Due to the complex shape and excellent material performance of the conical high-temperature alloy part, the traditional overall forging and cutting method has the problems of low material utilization rate, long machining cycle and large machining deformation. In recent years, additive manufacturing technology has been introduced into the preparation process of complex high-temperature alloy parts, and a near-net forming blank is quickly obtained through a layer-by-layer accumulation method. However, due to the stability of the additive process, the formed blank often has the following problems: uneven machining allowance, large allowance in some areas, and small allowance in some areas; the blank is conical in structure, and it is difficult to clamp, the traditional alignment method is low in efficiency, and the positioning reference is difficult to determine; during the machining process, if uniform allowance is cut, overcutting, undercutting or uneven wall thickness may occur, resulting in part rejection or deformation. SUMMARY

[0003] The technical problem solved by the application is to overcome the shortcomings of the prior art and provide a high-precision machining method for a conical high-temperature alloy part based on 3D additive manufacturing, which can ensure the consistency of the part wall thickness while improving the machining precision and efficiency.

[0004] The application is achieved by the following technical scheme: a high-precision machining method for a conical high-temperature alloy part based on 3D additive manufacturing, comprising: forming a clamping boss on the surface of the blank by additive manufacturing, and supporting and clamping the blank by the clamping boss of the machine tool; using a machine tool probe to detect the surface of the blank to obtain actual surface point cloud data; fitting the actual surface point cloud data to obtain a reference plane by the least square method, and obtaining an actual measurement point cloud model according to the reference plane; obtaining the allowance value of each measurement point according to the preset CAD theoretical model and the actual measurement point cloud model; establishing an allowance distribution model by using the inverse distance weighted interpolation algorithm according to the allowance value of each measurement point; taking the preset theoretical layer thickness as a reference, obtaining the local machining layer thickness according to the allowance distribution model, and generating an adaptive tool path according to the local machining layer thickness; and the machine tool processes according to the adaptive tool path.

[0005] In the above-mentioned high-precision machining method for a conical high-temperature alloy part based on 3D additive manufacturing, after the machine tool completes the machining, the in-machine measurement is performed again by the probe, the deviation between the actual surface and the target model is calculated, and if the deviation exceeds the set threshold, a supplementary cutting path is automatically generated for correction.

[0006] In the above-mentioned high-precision machining method for a conical high-temperature alloy part based on 3D additive manufacturing, the allowance value of each measurement point is obtained by the following formula: ; wherein, is the residual value of the th measurement point, is the actual point coordinate of the th measurement point, is the corresponding point coordinate on the theoretical surface of the th measurement point.

[0007] In the above high-precision machining method of conical high-temperature alloy parts based on 3D additive manufacturing, the residual distribution model is obtained by the following formula: ; wherein, is the spatial distance between any point and the th measurement point, is the weight index, is the number of measurement points, is the spatial distance between any point and the th measurement point, is the residual distribution function, is the axis coordinate, is the axis coordinate, is the axis coordinate.

[0008] In the above high-precision machining method of conical high-temperature alloy parts based on 3D additive manufacturing, the local machining layer thickness is obtained by the following formula: ; wherein, is the local machining layer thickness, is the residual distribution function, is the axis coordinate, is the axis coordinate, is the axis coordinate, is the theoretical layer thickness, is the global average residual.

[0009] In the above high-precision machining method of conical high-temperature alloy parts based on 3D additive manufacturing, the deviation between the actual surface and the target model is obtained by the following formula: ; wherein, is the deviation between the actual surface and the target model, is the target model, is the actual surface, is the axis coordinate, is axis coordinates, for axis coordinates.

[0010] In the high-precision machining method of the conical high-temperature alloy part based on 3D additive manufacturing, the clamping boss is a rectangular block structure, and the number of clamping bosses is multiple.

[0011] In the high-precision machining method of the conical high-temperature alloy part based on 3D additive manufacturing, the threshold is set to 0.01mm~0.05mm.

[0012] In the high-precision machining method of the conical high-temperature alloy part based on 3D additive manufacturing, the blank is a conical high-temperature alloy part, the height of the blank is 300~800mm, the large end diameter of the blank is 200~400mm, and the small end diameter of the blank is 10~30mm.

[0013] A high-precision machining system for a conical high-temperature alloy part based on 3D additive manufacturing, comprising: a first module for multi-point detection of the surface of the blank to obtain actual surface point cloud data; a second module for fitting the actual surface point cloud data to obtain a reference plane by least squares method, and obtaining an actual measurement point cloud model according to the reference plane; a third module for obtaining the excess value of each measurement point according to the preset CAD theoretical model and the actual measurement point cloud model; a fourth module for establishing an excess distribution model according to the excess value of each measurement point using the inverse distance weighted interpolation algorithm; and a fifth module for generating an adaptive tool path according to the local machining layer thickness generated according to the excess distribution model based on the preset theoretical layer thickness.

[0014] Compared with the prior art, the present application has the following advantages: (1) The present application realizes stable positioning of the blank by additive machining clamping boss and multi-point support, so that the clamping precision is improved; (2) The present application establishes a three-dimensional excess model based on in-machine measurement, realizes true reflection of complex casting morphology, and can accurately model the machining allowance; (3) The present application realizes "excess in multiple places and less machining, less excess in less places", effectively ensures the uniform wall thickness, so that the adaptive machining precision is high; (4) The present application avoids overcutting or air cutting, reduces trial cutting and alignment time, significantly improves machine tool utilization rate and product consistency, and improves machining efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of forming a clamping boss on the surface of a blank according to an embodiment of the present invention. Detailed Implementation

[0016] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] This embodiment provides a high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing. The method includes: forming a clamping boss on the surface of a blank through additive manufacturing; and using the clamping boss to support and clamp the blank. Figure 1 As shown, the clamping boss is a rectangular block structure, and there are multiple clamping bosses evenly distributed along the circumference of the blank. A machine tool probe is used to perform multi-point detection on the blank surface to obtain actual surface point cloud data. The actual surface point cloud data is fitted using the least squares method to obtain a reference plane, and an actual measured point cloud model is obtained based on the reference plane. The allowance value for each measurement point is obtained based on the preset CAD theoretical model and the actual measured point cloud model. An allowance distribution model is established using an inverse distance weighted interpolation algorithm based on the allowance value for each measurement point. Using the preset theoretical layer thickness as a reference, the local machining layer thickness is obtained based on the allowance distribution model, and an adaptive tool path is generated based on the local machining layer thickness. The machine tool performs machining according to the adaptive tool path.

[0018] This embodiment directly forms a clamping boss during the additive manufacturing stage of the blank and establishes an actual geometric model of the blank by combining the measurement data of the machine tool probe, thereby realizing adaptive adjustment and compensation machining of the allowance.

[0019] This high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing also includes: after machining on a machine tool, in-machine measurement is performed using a probe to calculate the deviation between the actual surface and the target model. If the deviation exceeds a set threshold, a correction path is automatically generated. The set threshold is 0.01mm to 0.05mm.

[0020] The margin value for each measurement point is obtained using the following formula: ; in, For the first The margin value at each measurement point For the first The actual coordinates of each measurement point For the first The coordinates of the corresponding points on the theoretical surface of each measurement point.

[0021] The residual distribution model is obtained through the following formula: ; in, For any point and the th Spatial distance between measurement points As a weighted index, The number of measurement points. For any point and the th Spatial distance between measurement points Let be the residual distribution function. for Axis coordinates for Axis coordinates for Axis coordinates.

[0022] The thickness of the local processing layer is obtained by the following formula: ; in, For localized processing layer thickness, Let be the residual distribution function. for Axis coordinates for Axis coordinates for Axis coordinates For the sake of theoretical thickness, This represents the average residual value across the entire region.

[0023] The deviation between the actual surface and the target model is obtained by the following formula: ; in, This represents the deviation between the actual surface and the target model. For the target model, For actual surfaces, for Axis coordinates for Axis coordinates for Axis coordinates.

[0024] The blank is a conical high-temperature alloy part with a height of 300~800mm, a large end diameter of 200~400mm, and a small end diameter of 10~30mm.

[0025] Specifically, the method includes the following steps: (1) Clamping and datum establishment: By forming clamping bosses on the surface of the blank through additive manufacturing, the clamping bosses are used for support and clamping. By adopting a multi-point support clamping method, the clamping bosses formed by additive manufacturing achieve stable positioning of the additive blank, avoiding clamping deformation caused by irregular shape of the blank. The machine tool probe is used to perform multi-point detection on the surface of the blank and collect point cloud data. The machine tool machining coordinate system is determined by fitting the reference plane using the least squares method. ; The least squares method fits the equation of the reference plane as follows:

[0026] By minimizing the objective function:

[0027] The plane coefficients are obtained, thereby establishing a machining reference coordinate system.

[0028] (2) Calculation of remaining margin: Spatial registration is performed between the probe points and the theoretical CAD model, and the machining allowance for each measurement point is calculated. The calculation formula is:

[0029] in, For the corresponding points in the CAD model; (3) Geometric modeling of the margin: Based on the residual values ​​at each measuring point, an inverse distance weighted interpolation algorithm is used to establish a residual distribution model, the expression of which is:

[0030] in, For any point and the th Spatial distance between measurement points For weighted index; (4) Adaptive toolpath generation: With theoretical thickness Based on the baseline, according to the residual function Calculate the thickness of the local processing layer:

[0031] When the local allowance is greater than the average allowance, the thickness of the processed layer increases accordingly; when the local allowance is less than the average allowance, the thickness of the processed layer decreases. (5) Processing execution and error correction: The generated toolpath is executed for machining. After machining, an in-machine measurement is performed using a probe to calculate the deviation between the actual surface and the target model.

[0032] If the deviation exceeds the set threshold ε, a replacement path will be automatically generated for correction.

[0033] The allowance distribution model is smoothed using B-spline surfaces to ensure the continuity and smoothness of the allowance field in toolpath calculation.

[0034] The toolpath generation module adopts a five-axis streamlined machining strategy based on the allowance distribution, and the tool axis direction is adjusted by vector projection based on the local normal to ensure stable tool cutting posture.

[0035] During machine measurement, the probe measurement error is processed through repeated measurements and statistical filtering. A mean filtering algorithm is used to correct outlier data; the correction formula is as follows:

[0036] The machining path generation is completed by the CAM software module, and measurement is achieved through a communication interface with the machine tool probe system. Modeling Processing closed-loop control.

[0037] Threshold for machining error correction The setting is adaptive based on the part's accuracy level, ranging from 0.01 to 0.05 mm.

[0038] It integrates with in-machine measurement systems, CNC machine tool control systems, and CAD / CAM software modules to achieve full-process automation of blank allowance detection, geometric modeling, machining path planning, and closed-loop correction.

[0039] Example (1) Clamping and datum establishment The additively manufactured blank is clamped with multiple supports. To improve clamping stability, four clamping bosses are formed on the blank using additive manufacturing. The tops of the bosses cooperate with special support blocks to achieve reliable positioning.

[0040] The machine tool's built-in probe is used to perform full-area detection of the workpiece's shape and collect point cloud data. The least squares method is used to fit the reference plane, and the equation is:

[0041] This determines the machining coordinate system. .

[0042] (2) Residual Calculation and Geometric Modeling Spatial registration will be performed between the point cloud data obtained from machine measurement and the theoretical CAD model.

[0043] The formula for calculating the local machining allowance at each point is:

[0044] in This refers to the corresponding point on the CAD model.

[0045] To generate a continuous residual distribution model, inverse distance weighted interpolation is used for the discrete residual data:

[0046] The resulting three-dimensional surface is the surplus distribution surface. This surface reflects the excess or deficiency characteristics of each region.

[0047] (3) Adaptive toolpath generation According to the residual function Adjust the local tool layer thickness. The theoretical layer thickness is... The actual processed layer thickness is:

[0048] when When this happens, the system automatically increases the step distance or deepens the cutting layer thickness; when If necessary, the layer thickness will be automatically reduced or a small step-pitch cutting method will be used.

[0049] The generated toolpath is smoothed and vector projected to maintain streamline continuity and smooth tool posture, adapting to the five-axis linkage machining strategy.

[0050] (4) Processing execution and error correction After processing, in-machine measurements are performed to calculate the deviation between the actual surface and the target model:

[0051] like (If an error threshold is set), the system will automatically generate a corrected tool path for supplementary cutting, forming a self-closed-loop machining process.

[0052] This method can achieve machining in a single setup. Measurement The modified closed-loop execution significantly reduces manual trial cutting and alignment operations.

[0053] Increasing the number of probe points from 100 to 300 improves the accuracy of the fitted geometric model. Test results show that this method can control wall thickness uniformity within ±0.05mm and improve processing efficiency by approximately 20%.

[0054] A clamping boss is synchronously additively manufactured on the large end face of the tapered high-temperature alloy blank. The clamping boss is concentrically arranged with the axis of the cone to ensure stable clamping and clear positioning datum during subsequent machining. Using the clamping boss as the clamping datum, the blank is clamped onto the CNC machine tool, avoiding the traditional problem of difficult alignment for tapered blanks. The machine tool's built-in trigger probe is used to detect multiple points on the blank surface. The detection points are distributed in a grid along the generatrix and circumferential direction, covering critical areas. Adaptive machining path planning: when the allowance is large, the cutting amount is increased in layers; when the allowance is small, the cutting amount is reduced or machining is avoided; when the allowance is uniform, conventional toolpath machining is performed. CNC cutting is performed according to the modified toolpath to ensure uniform part wall thickness and control machining deformation.

[0055] This embodiment also provides a high-precision machining system for conical high-temperature alloy parts based on 3D additive manufacturing. The system includes: a first module for multi-point detection of the blank surface to obtain actual surface point cloud data; a second module for fitting the actual surface point cloud data using the least squares method to obtain a reference plane, and obtaining an actual measured point cloud model based on the reference plane; a third module for obtaining the allowance value of each measurement point based on a preset CAD theoretical model and the actual measured point cloud model; a fourth module for establishing an allowance distribution model based on the allowance value of each measurement point using an inverse distance weighted interpolation algorithm; and a fifth module for obtaining the local machining layer thickness based on the allowance distribution model using a preset theoretical layer thickness as a reference, and generating an adaptive tool path based on the local machining layer thickness.

[0056] This embodiment improves clamping accuracy, solves the problems of clamping difficulty and difficulty in determining the benchmark, ensures uniform wall thickness, and avoids overcutting and undercutting, thereby significantly improving the processing efficiency and finished product quality of tapered high-temperature alloy parts. The method of this invention can improve processing accuracy and efficiency while ensuring the consistency of part wall thickness, and is particularly suitable for the precision machining of complex tapered high-temperature alloy parts.

[0057] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A high-precision machining method for a conical high-temperature alloy part based on 3D additive manufacturing, characterized in that... include: By forming clamping bosses on the surface of the blank through additive manufacturing, the machine tool uses the clamping bosses to support and clamp the blank. The actual surface point cloud data is obtained by using a machine tool probe to perform multi-point detection on the surface of the blank. A reference plane is obtained by fitting the actual surface point cloud data using the least squares method, and an actual measured point cloud model is obtained based on the reference plane. Based on the preset CAD theoretical model and the actual measured point cloud model, the margin value of each measurement point is obtained; A residual distribution model is established based on the residual value of each measurement point using an inverse distance weighted interpolation algorithm. Based on the preset theoretical layer thickness, the local machining layer thickness is obtained according to the allowance distribution model, and an adaptive tool path is generated based on the local machining layer thickness. The machine tool performs machining according to an adaptive toolpath.

2. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 1, characterized in that... Also includes: After the machine tool finishes processing, an in-machine measurement is performed using a probe to calculate the deviation between the actual surface and the target model. If the deviation exceeds a set threshold, a replacement cutting path is automatically generated for correction.

3. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 1, characterized in that: The margin value for each measurement point is obtained using the following formula: ； in, For the first The margin value at each measurement point For the first The actual coordinates of each measurement point For the first The coordinates of the corresponding points on the theoretical surface of each measurement point.

4. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 1, characterized in that: The residual distribution model is obtained through the following formula: ； in, For any point and the th Spatial distance between measurement points For weighted index, The number of measurement points. For any point and the th Spatial distance between measurement points Let be the residual distribution function. for Axis coordinates for Axis coordinates for Axis coordinates.

5. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 1, characterized in that: The thickness of the local processing layer is obtained by the following formula: ； in, For localized processing layer thickness, Let be the residual distribution function. for Axis coordinates for Axis coordinates for Axis coordinates For the sake of theoretical thickness, This represents the average residual value across the entire region.

6. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 2, characterized in that: The deviation between the actual surface and the target model is obtained by the following formula: ； in, This represents the deviation between the actual surface and the target model. For the target model, For actual surfaces, for Axis coordinates for Axis coordinates for Axis coordinates.

7. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 2, characterized in that: The clamping boss is a rectangular block structure, and there are multiple clamping bosses, which are evenly distributed along the circumference of the blank.

8. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 2, characterized in that: The threshold is set to 0.01mm ~ 0.05mm.

9. The high-precision machining method for tapered high-temperature alloy parts based on 3D additive manufacturing according to claim 2, characterized in that: The blank is a conical high-temperature alloy part with a height of 300~800mm, a large end diameter of 200~400mm, and a small end diameter of 10~30mm.

10. A high-precision machining system for conical high-temperature alloy parts based on 3D additive manufacturing, characterized in that... include: The first module is used to perform multi-point detection on the surface of the blank to obtain actual surface point cloud data; The second module is used to fit the actual surface point cloud data using the least squares method to obtain the reference plane, and then obtain the actual measured point cloud model based on the reference plane. The third module is used to obtain the margin value of each measurement point based on the preset CAD theoretical model and the actual measured point cloud model. The fourth module is used to establish a residual distribution model based on the residual value of each measurement point using an inverse distance weighted interpolation algorithm; The fifth module is used to obtain the local machining layer thickness based on the preset theoretical layer thickness and the allowance distribution model, and to generate an adaptive toolpath based on the local machining layer thickness.

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