Method for improving clamping accuracy of flexible bent frame

Abstract

The application discloses a method for improving clamping precision of flexible rack, and relates to the technical field of numerical control machine tool, which comprises the following steps: acquiring the positioning reference point space coordinates P1(x1, y1, z1), P2(x2, y2, z2) of positioning holes and mark holes in a part numerical model; clamping a skin part on the flexible rack, and acquiring the positioning reference point space coordinates S1(x3, y3, z3), S2(x4, y4, z4) of the positioning holes and mark holes in actual clamping of the skin part; acquiring the coordinate deviation absolute value of the positioning holes and mark holes; judging whether the coordinate deviation absolute value of the positioning holes and mark holes is within a tolerance range, if not, readjusting the installation position of the skin part and the flexible rack until the coordinate deviation absolute value is within the tolerance range. The positioning holes and mark holes of the skin part are used for common positioning, the gap between the theoretically designed positioning points in the numerical model and the actually measured positioning points is quantitatively measured by comparison, accurate positioning is realized, and the problem that the flexible rack cannot clamp a large-curvature complex skin part is effectively solved.

Description

Technical Field

[0001] This application relates to the field of CNC machining technology, specifically to a method for improving the clamping accuracy of flexible racks. Background Technology

[0002] Currently, the known positioning method for machining skin parts using a CNC machine tool with a flexible frame involves drilling positioning holes and marking holes at both ends of the skin part. The positioning holes are used for clamping and positioning the skin, and the marking holes determine the clamping direction. Based on the characteristics of the formed skin part, a CNC adjustable positioner is used to ensure that the normal line of the positioning pin on the positioner coincides with the normal line of the positioning hole on the skin part. The center of the spherical positioning pin serves as the machining reference. The adjusted positioner is used to fix the skin part, and the vacuum suction cup on the flexible frame further secures it. However, for complex skin parts with large curvature, the existing clamping method results in low positioning accuracy, easy part displacement, and machining deviations, failing to meet the manufacturing process requirements of skin parts. Therefore, existing large-curvature skin parts cannot be manufactured using CNC machine tools. Summary of the Invention

[0003] The main purpose of this application is to provide a method for improving the clamping accuracy of flexible frame, which aims to solve the technical problem that existing flexible frame clamping and positioning methods cannot accurately position skin parts with large curvature.

[0004] The technical solution adopted in this application is as follows:

[0005] A method for improving the clamping accuracy of flexible racks includes:

[0006] Obtain the spatial coordinates of the positioning reference points P1(x1,y1,z1) and P2(x2,y2,z2) of the positioning holes and mark holes in the part model;

[0007] The skin part is clamped on a flexible frame, and the spatial coordinates of the positioning reference points S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning holes and mark holes in the actual clamping of the skin part are obtained.

[0008] Based on the spatial coordinates P1(x1,y1,z1), P2(x2,y2,z2) of the positioning reference points of the positioning holes and marking holes in the part model and the spatial coordinates S1(x3,y3,z3), S2(x4,y4,z4) of the positioning reference points of the positioning holes and marking holes in the actual clamping of the skin part, the absolute values ​​of the coordinate deviations of the positioning holes and marking holes are obtained.

[0009] Determine whether the absolute value of the coordinate deviation of the positioning hole and the mark hole is within the tolerance range. If not, readjust the installation position of the skin parts and the flexible frame until the absolute value of the coordinate deviation is within the tolerance range.

[0010] Optionally, obtaining the spatial coordinates P1(x1,y1,z1) and P2(x2,y2,z2) of the positioning reference points for the positioning holes and mark holes in the part model includes:

[0011] Determine the positions of the positioning holes and marking holes in the part's digital model;

[0012] Draw a straight line along the normal direction of the plane of the part containing the positioning hole and the mark hole respectively. The position at a distance equal to the radius of the spherical positioning pin is taken as the positioning reference point, namely P1 and P2. The spatial coordinates of points P1 and P2 relative to the origin of the machine tool coordinate system are the spatial coordinates of the positioning reference points of the positioning hole and the mark hole in the part model, namely P1(x1,y1,z1) and P2(x2,y2,z2).

[0013] Optionally, obtain the spatial coordinates S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning reference points for the positioning holes and mark holes in the actual clamping of the skin part, including:

[0014] After the skin part is clamped onto the flexible frame, the suction cups on the flexible frame are activated to vacuum and adsorb the skin part.

[0015] After the skin parts are completely adsorbed and fixed, remove the spherical locating pins located in the positioning holes and marking holes, observe whether the parts have deformed or shifted, and then reinstall the spherical locating pins into the positioning holes and marking holes.

[0016] By using the gantry laser head on the CNC machine tool, the spatial coordinates of the center of the spherical locating pin on the positioning hole and the marking hole relative to the machine tool are detected. These coordinates are the spatial coordinates of the positioning reference points S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning hole and the marking hole in the actual clamping of the skin part.

[0017] Optionally, when clamping the skin parts onto the flexible frame, it is necessary to ensure that the normal of the spherical locating pin coincides with the normal of the corresponding locating hole and marking hole.

[0018] Optionally, after the skin part is completely adsorbed and fixed, the vacuum degree measured for each column used to support the skin part needs to be greater than 90%.

[0019] Optionally, the step of obtaining the absolute value of the coordinate deviation of the positioning holes and marking holes based on the spatial coordinates P1(x1,y1,z1), P2(x2,y2,z2) of the positioning reference points of the positioning holes and marking holes in the digital model of the part and the spatial coordinates S1(x3,y3,z3), S2(x4,y4,z4) of the positioning reference points of the positioning holes and marking holes in the actual clamping of the skin part includes:

[0020] Find the difference between the corresponding coordinates of P1(x1,y1,z1) and P2(x2,y2,z2) to obtain the reference vector P(x1-x2, y1-y2, z1-z2);

[0021] Find the difference between the corresponding coordinates of S1(x3,y3,z3) and S2(x4,y4,z4) to obtain the measurement vector S = (x3-x4, y3-y4, z3-z4);

[0022] By subtracting the corresponding coordinate values ​​of the measurement vector from those of the reference vector, the absolute value of the coordinate deviation between the positioning hole and the marker hole can be obtained.

[0023] Optionally, the tolerance range is less than or equal to 0.5.

[0024] Compared with the prior art, the beneficial effects of this application are:

[0025] This application proposes a method to improve the clamping accuracy of flexible frame components. This method utilizes the positioning holes and marking holes of the skin parts for joint positioning. By comparing the theoretical positioning points designed in the digital model with the actual measured positioning points, the difference between the two can be quantitatively measured, enabling precise positioning. This effectively solves the problem that flexible frames cannot clamp complex skin parts with large curvatures. Furthermore, measurements can be taken on the flexible frame using a CNC machine tool, providing the error between the actual clamping and theoretical values. This allows operators to adjust the parts promptly and achieve precise positioning. This method can further improve the accuracy of parts processed by CNC machine tools. Detailed Implementation

[0026] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] This application provides a method for improving the clamping accuracy of flexible racks, including:

[0028] S1: Obtain the spatial coordinates of the positioning reference points P1(x1,y1,z1) and P2(x2,y2,z2) of the positioning holes and mark holes in the part model;

[0029] S2: Clamp the skin part onto the flexible frame and obtain the spatial coordinates of the positioning reference points S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning holes and mark holes in the actual clamping of the skin part.

[0030] S3: Based on the spatial coordinates P1(x1,y1,z1), P2(x2,y2,z2) of the positioning reference points of the positioning holes and marking holes in the part model and the spatial coordinates S1(x3,y3,z3), S2(x4,y4,z4) of the positioning reference points of the positioning holes and marking holes in the actual clamping of the skin part, obtain the absolute value of the coordinate deviation of the positioning holes and marking holes.

[0031] S4: Determine whether the absolute value of the coordinate deviation of the positioning hole and the mark hole is within the tolerance range. If not, readjust the installation position of the skin parts and the flexible frame until the absolute value of the coordinate deviation is within the tolerance range.

[0032] It can be observed that this method utilizes the positioning holes and marking holes of the skin parts for joint positioning. By comparing the theoretical positioning points designed in the digital model with the actual measured positioning points, the difference between the two can be quantitatively measured, enabling precise positioning. This effectively solves the problem that flexible frames cannot clamp complex skin parts with large curvatures. Moreover, CNC machine tools can be used on the flexible frame to measure the error between the actual clamping and the theoretical values, facilitating timely adjustment of parts by operators for precise positioning. This method can further improve the accuracy of parts processed by CNC machine tools.

[0033] Specifically:

[0034] This application provides a method for improving the clamping accuracy of flexible racks, the detailed steps of which are as follows:

[0035] First, determine the positioning holes and marking holes of the part based on the actual processing technology. The positioning holes are used for skin clamping and positioning, and the marking holes determine the skin clamping direction.

[0036] Next, create the positioning holes and marker holes in the part's digital model. Draw a straight line along the normal direction of the part's plane containing the positioning holes and marker holes, with the distance equal to the radius of the spherical locating pin as the positioning reference point (i.e., the center of the spherical locating pin). Record the positioning reference point where the positioning hole is located as P1 and the positioning reference point where the marker hole is located as P2. Obtain the spatial coordinates of P1 and P2 relative to the machine tool's coordinate origin: P1(x1,y1,z1) and P2(x2,y2,z2). Subtract the corresponding x, y, and z coordinate values ​​of P1 and P2 (x1-x2, y1-y2, z1-z2) to obtain the differences in the x, y, and z directions, which serve as the reference vectors. That is, P(x) p ,y p ,z p )=(P1–P2)=(x1-x2,y1-y2,z1-z2);

[0037] Next, install the skin part on the flexible frame. Adjust the locator to ensure that the normal of the spherical locating pin coincides with the normal of the corresponding locating hole and mark hole, ensuring accurate machining datum. After the skin part is installed on the flexible frame, the suction cups on the flexible frame are turned on to activate the vacuum. The vacuum degree measured for each column supporting the part must be greater than 90%. The purpose is to restore the theoretical surface of the skin part to the part after vacuum adsorption, so that any surface changes that may have occurred in the previous process. After the part is adsorbed, remove the two spherical locating pins from the locator. After removal, observe that the part should not have any deformation or displacement. Then, install the spherical locating pins back onto the locator. During the removal and installation of the spherical locating pins, there should be no increase in friction. Otherwise, it can be considered that the part has undergone a slight deformation near the locating hole. If a slight deformation occurs, it needs to be re-clamped.

[0038] Finally, using the gantry laser head on the CNC machine tool, the spatial coordinates S1(x3,y3,z3) and S2(x4,y4,z4) of the center of the spherical locating pins on the positioning holes and marking holes relative to the origin of the machine tool coordinate system are detected. The x, y, and z coordinate values ​​of the two measured spatial coordinates S1 and S2 are subtracted to obtain the differences in the x, y, and z directions, which are used as the measurement vectors. That is, S(x) s ,y s ,z s )=(S1–S2)=(x3-x4,y3-y4,z3-z4), subtracting the coordinate values ​​corresponding to the measurement vector from the reference vector yields the deviation vector, i.e., D=S–P=(x s -x p ,y s -y p ,z s -z p The absolute values ​​of the three directions in the deviation vector represent the difference between the clamping process and the theoretical design, i.e., |D| = |S – P| = (|x s -x p |,|y s -y p |,|z s -z p If all three differences are less than or equal to 0.5mm, the relative position of the part with respect to the flexible frame can be approximately considered to be consistent with the design in the digital model. If any one of the directions is greater than 0.5mm, it needs to be reinstalled. Only when all three coordinates of the measured deviation vector are less than or equal to 0.5mm can the requirements be met. After the positioning is correct, the subsequent CNC machining process of the part can be carried out.

[0039] In summary, this method utilizes the positioning holes and directional holes of the skinned parts for joint positioning. By comparing the theoretical positioning points designed in the digital model with the actual measured positioning points, the difference between the two can be quantitatively measured, enabling precise positioning. Furthermore, by using the vacuum support columns of the flexible frame to hold the parts in place, minimizing minor deformations, the skinned parts can be effectively and precisely positioned within the flexible frame of the CNC machine tool, further improving the accuracy of parts processed by CNC machine tools.

[0040] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for improving the clamping accuracy of flexible racks, characterized in that, include: Obtain the spatial coordinates of the positioning reference points P1(x1,y1,z1) and P2(x2,y2,z2) of the positioning holes and mark holes in the part model; The skin part is clamped on a flexible frame, and the spatial coordinates of the positioning reference points S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning holes and mark holes in the actual clamping of the skin part are obtained. Based on the spatial coordinates P1(x1,y1,z1) and P2(x2,y2,z2) of the positioning reference points of the positioning holes and mark holes in the part's digital model, the difference between the corresponding coordinates of P1(x1,y1,z1) and P2(x2,y2,z2) is calculated to obtain the reference vector. (x1-x2, y1-y2, z1-z2); Based on the spatial coordinates S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning reference points of the positioning holes and mark holes in the actual clamping of the skin part, the difference between the corresponding coordinates of S1(x3,y3,z3) and S2(x4,y4,z4) is calculated to obtain the measurement vector. =(x3-x4, y3-y4, z3-z4) Subtract the corresponding coordinate values ​​of the measurement vector from the reference vector to obtain the absolute value of the coordinate deviation between the positioning hole and the mark hole; Determine whether the absolute value of the coordinate deviation of the positioning hole and the mark hole is within the tolerance range. If not, readjust the installation position of the skin parts and the flexible frame until the absolute value of the coordinate deviation is within the tolerance range.

2. The method for improving the clamping accuracy of flexible racks according to claim 1, characterized in that, The process of obtaining the spatial coordinates P1(x1,y1,z1) and P2(x2,y2,z2) of the positioning reference points for the positioning holes and mark holes in the digital model of the part includes: Determine the positions of the positioning holes and marking holes in the part's digital model; Draw a straight line along the normal direction of the plane of the part containing the positioning hole and the mark hole respectively. The position at a distance equal to the radius of the spherical positioning pin is taken as the positioning reference point, namely P1 and P2. The spatial coordinates of points P1 and P2 relative to the origin of the machine tool coordinate system are the spatial coordinates of the positioning reference points of the positioning hole and the mark hole in the part model, namely P1(x1,y1,z1) and P2(x2,y2,z2).

3. The method for improving the clamping accuracy of flexible racks according to claim 1, characterized in that, Obtain the spatial coordinates S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning reference points for the positioning holes and mark holes in the actual clamping of the skin part, including: After the skin part is clamped onto the flexible frame, the suction cups on the flexible frame are activated to vacuum and adsorb the skin part. After the skin parts are completely adsorbed and fixed, remove the spherical locating pins located in the positioning holes and marking holes, observe whether the parts have deformed or shifted, and then reinstall the spherical locating pins into the positioning holes and marking holes. By using the gantry laser head on the CNC machine tool, the spatial coordinates of the center of the spherical locating pin on the positioning hole and the marking hole relative to the machine tool are detected. These coordinates are the spatial coordinates of the positioning reference points S1(x3,y3,z3) and S2(x4,y4,z4) of the positioning hole and the marking hole in the actual clamping of the skin part.

4. The method for improving the clamping accuracy of flexible racks according to claim 3, characterized in that, When clamping skin parts onto a flexible frame, it is necessary to ensure that the normal of the spherical locating pin coincides with the normal of the corresponding locating hole and marking hole.

5. The method for improving the clamping accuracy of flexible racks according to claim 3, characterized in that, After the skin parts are completely adsorbed and fixed, the vacuum degree measured for each column used to support the skin parts must be greater than 90%.

6. The method for improving the clamping accuracy of flexible racks according to claim 1, characterized in that, The tolerance range is less than or equal to 0.5.