A method for layered detection and continuous compensation of boring machining errors

Abstract

This invention discloses a method for layered detection and continuous compensation of boring machining errors, comprising the following steps: performing layered on-machine inspection on semi-finished holes, with the number of inspection layers and the number of measurement points per layer customizable before inspection; calculating the position of compensation points in each layer and fitting a continuous compensation curve in three-dimensional space; discretizing the compensation curve into denser compensation points and converting it into boring machining code for compensation correction. This invention mainly addresses the problems of boring positional accuracy and dimensional accuracy by employing a layered detection and continuous compensation method for correction, which has guiding significance for improving the machining accuracy of boring machines.

Description

Technical Field

[0001] This invention relates to the field of CNC machining technology, and in particular to a method for layered detection and continuous compensation of boring machining errors. Background Technology

[0002] Boring error detection and compensation is an economical and effective method for controlling the dimensional and positional accuracy of boring processes and ensuring product interchangeability. It can improve hole machining quality more conveniently and efficiently without optimizing the boring machine structure or adjusting precision, making it a widely used method in modern manufacturing. Common on-machine inspection methods in boring machines, such as the three-point or four-point circle measurement programs equipped by Renishaw and Huazhong CNC, have a limited number of measurement points and generally cannot customize the number of measurements per revolution. When the hole diameter is large, using fewer measurement points for measurement and evaluation will result in significant errors; furthermore, the auxiliary paths in the inspection process are too long and repetitive, affecting inspection efficiency. In addition, for a hole with a large depth, the offset and dimensional change corresponding to each longitudinal position are variable, making it impossible to use a single value or orientation for uniform and precise compensation. These factors limit the further development of precision boring, and existing on-machine inspection and compensation machining technologies urgently need improvement. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and address the lack of efficient, high-precision, and integrated on-machine inspection and compensation methods for boring operations, especially for large-diameter and deep holes. This invention proposes a layered inspection and continuous compensation method for boring errors. In the inspection stage, the number of circumferential and longitudinal layers of inspection points can be customized based on the theoretical diameter and depth of the hole. The compensation process does not merely compensate for the measurement positions but transforms discrete information into a continuous compensation machining space curve, thereby performing continuous compensation machining. This method improves the dimensional and positional accuracy of boring operations while maintaining inspection efficiency.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for layered detection and continuous compensation of boring machining errors includes the following steps:

[0006] (1) Perform layered in-machine inspection on the test hole after semi-finishing, wherein the number of test layers, the test interval and the number of test points in each layer are predefined;

[0007] (2) Determine whether the theoretical axis coordinates of the hole to be tested are known before testing; if unknown, proceed to step (3); if known, proceed to step (4).

[0008] (3) Move the probe of the machine to the hole to be tested and lower than the upper surface of the hole to be tested, execute the test command to determine the center, and stop the probe at the center position of the hole to be tested;

[0009] (4) Set the current center position of the circle to a known value;

[0010] (5) Generate a detection program based on the set information, and execute the detection program by a CNC boring machine to obtain the coordinates of the measuring points in each layer;

[0011] (6) Based on the least squares fitting circle method, the coordinates of each layer of measurement points are fitted into corresponding circles to obtain the size of each circle and the corresponding center coordinates of the circle;

[0012] (7) Adjust the boring tool radius according to the average value of the radius of each layer of circle evaluation;

[0013] (8) Mirror the center of each evaluated circle about the theoretical center and calculate the position of the compensation point for each layer;

[0014] (9) Fit a continuous spatial compensation curve based on the compensation points;

[0015] (10) Customize the number of compensation layers, discretize the compensation curve into denser compensation points, and convert them into boring machining code for finishing compensation correction.

[0016] Furthermore, the probe is a point contact probe.

[0017] Furthermore, the CNC boring machine is capable of running testing programs and boring machining programs.

[0018] Furthermore, the number of detection layers and the detection interval in step (1) are defined according to the depth of the hole to be tested.

[0019] Furthermore, the detection command described in step (3) refers to the positioning program that comes with the CNC boring machine.

[0020] Furthermore, in step (9), the spatial compensation curve is obtained based on the 3rd NURBS fitting method, and the number of measurement layers must reach the minimum fitting number of the 3rd NURBS curve, which is 4.

[0021] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the boring machining error layer detection and continuous compensation method.

[0022] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the boring machining error layer detection and continuous compensation method.

[0023] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0024] 1. Improved hole evaluation accuracy: It makes up for the problem that traditional boring machines have a small number of on-machine inspection points and it is difficult to customize the number of inspections. For large-diameter holes, increasing the number of inspections plays a more beneficial role in the accuracy evaluation after boring.

[0025] 2. Improved in-machine inspection efficiency of holes: It makes up for the shortcomings of traditional boring machines, which have excessively long auxiliary inspection distances and cannot automatically and continuously complete multi-layer inspections, thus improving inspection efficiency under the same conditions.

[0026] 3. Improved the positional and dimensional errors after boring, and also improved the problem of poor consistency in the axial error distribution of boring: The discrete information between layers is processed into a continuous curve in three-dimensional space, and then continuous compensation processing is performed to improve the overall machining accuracy of the hole.

[0027] 4. Improve the machining efficiency and quality of CNC boring machines: Through more precise in-machine inspection and compensation machining, this invention helps to optimize the process strategy of CNC boring machines, thereby improving machining efficiency and the quality of the produced parts.

[0028] 5. Promote technological progress in manufacturing: The application of this invention helps to promote technological progress in manufacturing, especially in the field of high-precision hole manufacturing, and provides more efficient and accurate production solutions for related industries. Attached Figure Description

[0029] Figure 1 This is a flowchart of layered detection and continuous compensation.

[0030] Figure 2 This is a schematic diagram of single-layer circumferential detection and axial layering;

[0031] Figure 3 This is a schematic diagram of the compensation curve and dense compensation points. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] To improve the efficiency of in-machine inspection and the effectiveness of evaluation results, and to enhance the positional and dimensional accuracy of parts, this embodiment provides a method for layered detection and continuous compensation of boring machining errors. (See [link to relevant documentation]). Figure 1 See the description below for details:

[0034] In the specific implementation of boring machine machining, this method mainly consists of two stages: on-machine inspection and continuous compensation. Specifically, the on-machine inspection stage generates an inspection program based on customized inspection information. By running the on-machine inspection program, the actual coordinates of multiple longitudinal layers and circumferential points within the test hole after semi-finishing are obtained. The compensation stage uses the least squares method to fit the center coordinates of each layer, and calculates the compensation center coordinates relative to the theoretical center using the mirror method. Then, cubic NURBS is used to fit the compensation center into a continuous spatial compensation curve. Finally, the compensation curve is discretized into denser compensation coordinates, thereby generating the compensation machining code for boring machine operation to perform finishing.

[0035] Specifically, the boring machining error layer detection and continuous compensation method provided in this embodiment includes the following steps:

[0036] (1) For a semi-finished hole to be tested, perform layered in-machine inspection. The number of inspection layers is m∈[1,M], the number of inspection points in each layer is n∈[1,N], and the interval between layers is k. For details on single-layer circumferential inspection and hole layering, please refer to [link to documentation]. Figure 2 .

[0037] (2) Obtain the actual measured point cloud P after on-machine detection:

[0038]

[0039] in, This represents the j-th measurement point in the i-th layer, with its corresponding X, Y, Z coordinates as follows:

[0040] (3) Based on the N actual measured coordinates of each layer, use the least squares method to fit circles and obtain N circles with the following center coordinates:

[0041]

[0042] in, This represents the center of the circle fitted by the i-th layer, and its corresponding X, Y, Z coordinates are:

[0043] Given the theoretical center of the hole during machining and its corresponding X, Y, Z coordinates as O = (x l ,y l ,z l If the coordinates of the compensation center of this Nth layer are:

[0044]

[0045] in, This represents the position of the compensation center of the i-th layer, with corresponding X, Y, Z coordinates.

[0046]

[0047] (4) The coordinates of the compensation center are fitted to a spatial compensation curve using cubic NURBS. The NURBS curve fitting formula is as follows:

[0048]

[0049] Among them, C i To form the control points of the control polygon, ω i It is a weight factor, N i,d It is a d-order B-spline basis function defined on a non-periodic (and non-uniform) node vector.

[0050] (5) If the number of compensation layers is defined as T, then T points are uniformly selected within the node range of [0,1] as compensation points, and the coordinates of these T points are solved in a forward direction:

[0051]

[0052] Among them, H i This represents the i-th compensation point, whose corresponding X, Y, Z coordinates are [x...]. i ,y i ,z i The compensation curve and dense compensation points are as follows: Figure 3 As shown.

[0053] (6) Convert the machining program based on the compensation point after continuous machining. This machining program enables the boring machine to perform the following actions:

[0054] In the first layer, using the X and Y coordinates of H1 as a reference, bore downwards to the Z-axis height corresponding to H1, then lift to the auxiliary plane; in the second layer, using the X and Y coordinates of H2 as a reference, bore downwards to the Z-axis height corresponding to H2, then lift to the height of the upper surface of layer H2... Finally, in layer T, using H... T Using the X and Y coordinates as a reference, bore downwards to the bottom layer, and then lift it to the auxiliary plane.

[0055] Specifically, in this embodiment, in-machine inspection and compensation machining of the hole are performed on a CNC vertical boring machine. After the semi-finishing of the hole to be tested is completed, layered in-machine inspection is performed. The number of inspection layers is set to 5, with 8 points inspected circumferentially in each layer, and the distance between layers is 5mm. In this embodiment, the point cloud data of the measurement points is partially obtained as shown in the following table:

[0056]

[0057]

[0058] The coordinates of the center of each layer and the theoretical center obtained from the fitting are shown in the table below:

[0059] Theoretical center -239.0444 -524.3619 0.0000 First layer center -239.0485 -524.3631 0.0000 Second layer center -239.0483 -524.3625 -5.0000 The third layer center -239.0485 -524.3626 -10.0000 Fourth layer center -239.0489 -524.3627 -15.0000 Fifth layer center -239.0490 -524.3627 -20.0000

[0060] The coordinates of the compensation center of each layer were calculated based on the theoretical center coordinates. Then, the spatial compensation curve was fitted using cubic NURBS. With 9 compensation layers set, the positions of the 9 continuous compensation points are shown in the table below:

[0061]

[0062]

[0063] Based on the continuous compensation point coordinates, specific compensation machining codes are generated. Simultaneously, the boring tool radius is adjusted for finishing. After machining, an inspection is performed, and the positional error is compared with that before compensation. The results are shown in the table below:

[0064] 0.004339266 0.00113396

[0065] The embodiments of this application also provide a specific implementation of an electronic device capable of generating in-machine detection code and compensation machining code in the boring machining error layer detection and continuous compensation method described in the above embodiments. The electronic device specifically includes the following:

[0066] The system includes a memory, a processor, a communication interface, a bus, and a computer program stored in the memory and executable on the processor. The memory and processor are connected via the bus. The processor, memory, and communication interface communicate with each other via the bus; the communication interface is used for information transmission between server-side devices, metering devices, and user-side devices. When the processor executes the computer program, it implements the boring machining error layer detection and continuous compensation method described in the preceding embodiments. The number of processors can be one or more.

[0067] The embodiments of this application also provide a computer-readable storage medium capable of implementing all steps of the boring machining error layer detection and continuous compensation method in the above embodiments. The computer-readable storage medium stores a computer program that, when executed by a processor, implements all steps of the boring machining error layer detection and continuous compensation method in the above embodiments.

[0068] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Conventional or non-inventive labor may include more or fewer operational steps. The order of steps listed in the embodiments is merely one possible execution order among many steps and does not represent the only possible execution order. Furthermore, the process depicted in the accompanying drawings does not necessarily require the specific order or sequential order shown to achieve the desired result.

[0069] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, USB flash drives, portable hard drives, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0070] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0071] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0072] Those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A method for layered detection and continuous compensation of boring machining errors, characterized in that, Includes the following steps: (1) Perform layered in-machine inspection on the test hole after semi-finishing, wherein the number of test layers, the test interval and the number of test points in each layer are predefined; (2) Determine whether the theoretical axis coordinates of the hole to be tested are known before testing; if unknown, proceed to step (3); if known, proceed to step (4). (3) Move the probe of the machine to the hole to be tested and lower than the upper surface of the hole to be tested, execute the test command to determine the center, and stop the probe at the center position of the hole to be tested; (4) Set the current center position of the circle to a known value; (5) Generate a detection program based on the set information, and execute the detection program by a CNC boring machine to obtain the coordinates of the measuring points of each layer; (6) Based on the least squares fitting circle method, fit the coordinates of the measurement points of each layer into the corresponding circles, and obtain the size of each circle and the corresponding center coordinates; (7) Adjust the boring tool radius according to the average value of the radius of each layer of circles; (8) Mirror the center of each layer of the evaluated circle about the theoretical center, and calculate the position of the compensation point for each layer; (9) Fit a continuous spatial compensation curve based on the compensation point, wherein the spatial compensation curve is obtained based on the 3rd NURBS fitting method, and the number of measurement layers must reach the minimum fitting number of the 3rd NURBS curve, which is 4. (10) Customize the number of compensation layers, discretize the compensation curve into denser compensation points, and convert them into boring machining code for finishing compensation correction.

2. The method for layered detection and continuous compensation of boring machining errors according to claim 1, characterized in that, The probe is a point contact probe.

3. The method for layered detection and continuous compensation of boring machining errors according to claim 1, characterized in that, The CNC boring machine is capable of running testing programs and boring machining programs.

4. The method for layered detection and continuous compensation of boring machining errors according to claim 1, characterized in that, The number of detection layers and the detection interval mentioned in step (1) are defined according to the depth of the hole to be tested.

5. The method for layered detection and continuous compensation of boring machining errors according to claim 1, characterized in that, The detection command mentioned in step (3) refers to the positioning program that comes with the CNC boring machine.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the boring machining error layer detection and continuous compensation method according to any one of claims 1 to 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the boring machining error layer detection and continuous compensation method according to any one of claims 1 to 5.

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