Integral box bottom mirror image milling quality analysis method

Abstract

The invention provides an integral box bottom mirror image milling processing quality analysis method. The method comprises the following steps: step 1, reading a processing process file in a mirror image milling process; 2, according to a preset algorithm, formal machining point positions in the machining process file are recognized, normal vectors and wall thickness line segment lengths of all the formal machining point positions are calculated, and according to different wall thickness ranges, different colors are defined for wall thickness line segments; 3, wall thickness lines of all the formal machining cutter location points are drawn, and all the wall thickness lines are rendered according to colors; 4, counting the wall thickness tolerance ranges of all the formal machining cutter location points, analyzing the proportion value of the tolerance ranges, judging whether machining is qualified or not, and displaying the machining results in three-dimensional software in a dialog box mode. According to the method, the processing quality information is identified, the processing quality can be visually displayed and accurately calculated in the forms of colors, line segment lengths, statistical data and the like, and the processing quality analysis efficiency and accuracy can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of numerical control machining, and in particular to a method for analyzing the machining quality of an integral box bottom mirror milling. Background Art

[0002] The tank bottom is an important component of the fuel tank of a launch vehicle. It is a typical thin-walled, large-size, complex curved surface part. The design profile of the tank bottom is the surface of revolution of the first quadrant curve of the ellipse around the minor axis. In order to achieve the transmission of fuel, it is generally designed with several through holes for subsequent welding with other parts. At the same time, the wall thickness is locally thickened as the welding influence zone. Therefore, the tank bottom generally has features such as through holes and thickened areas on the outer surface, and the structure is relatively complex. Due to its complex structure and high quality requirements, it has become one of the most difficult products to process among the launch vehicle structural parts.

[0003] The overall bottom area of ​​the storage tank is large. Generally, the surface area of ​​a 3-meter-level overall bottom exceeds 12 square meters. According to the quality control requirements of the overall bottom, it is necessary to measure the wall thickness data of the overall bottom as an important basis for quality evaluation. However, the traditional handheld ultrasonic thickness measurement process has low measurement efficiency and relies on manual recording of measurement data, which affects the effective evaluation of the mirror milling processing quality of the overall bottom.

[0004] Mirror milling is the mainstream processing method for the processing of the overall bottom of the box. During the mirror milling process, various data in the processing process can be automatically collected, including the position information of each axis of the equipment, wall thickness information, eddy current information and more than 30 kinds of processing data. However, the acquisition frequency in the mirror milling process is as high as microseconds, and the total sampling points exceed 100,000. The traditional analysis method has low processing efficiency, and the pure digital analysis lacks the intuitive display of the corresponding relationship with the overall bottom of the box product and characteristics, which is not conducive to the accurate and visual analysis of the overall bottom of the box quality. Summary of the invention

[0005] In view of the defects in the prior art, the object of the present invention is to provide a method for analyzing the quality of mirror milling of an integral box bottom.

[0006] The method for analyzing the quality of the overall box bottom mirror milling provided by the present invention comprises: Step 1: Read the processing file during the mirror milling process; Step 2: Identify the formal processing points in the processing process file according to the preset algorithm, calculate the normal vectors and wall thickness line segment lengths of all formal processing points, and define different colors for the wall thickness line segments according to different wall thickness ranges; Step 3: In the 3D software, according to the coordinate value of the formal processing point, the normal vector value, the length value and color of the wall thickness line, draw the wall thickness lines of all formal processing tool positions, and render all the wall thickness lines according to the color; Step 4: According to the wall thickness information, the wall thickness tolerance range of all formal processing tool positions is counted, and the proportion value of the tolerance range is analyzed to determine whether the processing is qualified, and it is displayed in the 3D software in the form of a dialog box.

[0007] Preferably, in step 1, the machining process file includes the coordinate values ​​of the five outer axes X, Y, Z, A, C on the milling side of the mirror milling equipment and the five inner axes X2, Y2, Z2, A2, C2 on the measuring side at each tool position, the position values ​​Px, Py, Pz in the workpiece coordinate system, and the measured wall thickness value H at the current tool position; the machining process file is created and generated according to the time index.

[0008] Preferably, in step 2, the coordinate values ​​of the outer five-axis A / C axis and the inner five-axis A2 / C2 axis of the mirror milling equipment are compared to see if they are equal. If they are equal, the point is judged to be the formal processing point, otherwise it is the feed and retract point.

[0009] Preferably, in step 2, the normal vector value of the formal processing tool position point is calculated according to the A / C axis angle value of the mirror milling equipment through homogeneous matrix operation, and the difference between the actual wall thickness and the theoretical wall thickness is calculated according to the theoretical wall thickness value as the wall thickness tolerance of the current tool position point, the tool position point in the processing process file is used as the starting point of the wall thickness line, the vector direction, magnification factor and wall thickness tolerance are calculated to obtain the end point of the wall thickness line, and the color of the wall thickness line is set according to the preset wall thickness tolerance range.

[0010] Preferably, according to the coordinate values ​​of the A-axis and C-axis of the five external axes on the milling side, the normal vectors Nx, Ny, and Nz of the tool position point are calculated through a homogeneous transformation matrix; Nx=sinCsinA(1) Ny=-cosCsinA(2) Nz=cosA(3) Where Nx, Ny, and Nz are the X, Y, and Z axis components of the tool axis vector of the point, respectively; C and A are the coordinate values ​​of the C and A axes of the five external axes of the point, respectively; Read the input theoretical wall thickness value Hm and the set tolerance range DH, and calculate the wall thickness tolerance value Hc=H-Hm at this point; read the input wall thickness tolerance range, determine the tolerance range where Hc is located, and define the color of the wall thickness line at this point according to the range. If Hc<0, set the wall thickness line to the first color; if 0≤Hc≤DH, set the wall thickness line to the second color; if Hc>DH, set the wall thickness line to the third color; According to the coordinate values ​​Px, Py, and Pz in the workpiece coordinate system in the process file, they are defined as the starting coordinates Px1, Py1, and Pz1 of the wall thickness line: Px1=Px(4) Py1=Py(5) Pz1=Pz(6) Where, Px1, Py1, and Pz1 are the X, Y, and Z axis coordinate values ​​of the starting point coordinates of the wall thickness line, respectively; Px, Py, and Pz are the X, Y, and Z axis coordinate values ​​of the workpiece coordinate system in the process file, respectively; Read the input magnification factor K, and calculate the wall thickness line length L as the product of the wall thickness tolerance value and the magnification factor, that is, L=K×Hc; according to the calculated normal vectors Nx, Ny, Nz, the starting coordinates Px, Py, Pz of the wall thickness line and the length L of the wall thickness line, calculate the end coordinates of the wall thickness line: Px2=Px1+Nx×L(7) Py2=Py1+Ny×L(8) Pz2=Pz1+Nz×L(9) Wherein, Px2, Py2, and Pz2 are the end point coordinates of the wall thickness line, Px1, Py1, and Pz1 are the starting point coordinates of the wall thickness line, and L is the length of the wall thickness line.

[0011] Compared with the prior art, the present invention has the following beneficial effects: (1) The overall box bottom mirror milling processing quality analysis method of the present invention can automatically identify and visualize the overall box bottom wall thickness information, greatly improving the analysis efficiency, and the visualized display can accurately locate the wall thickness tolerance distribution; (2) The overall box bottom mirror image milling processing quality analysis method of the present invention can automatically count the distribution of each wall thickness tolerance interval, provide quantitative data for wall thickness quality analysis, and improve the accuracy of processing quality judgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a schematic flow chart of the quality analysis method of the overall box bottom mirror milling process of the present invention. DETAILED DESCRIPTION

[0013] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0014] Example Figure 1The figure is a flow chart of the overall bottom mirror milling quality analysis method of the present invention. The overall bottom mirror milling quality analysis method provided by the present invention is as follows: Figure 1 As shown in , it includes the following steps: Step 1: Read the processing file of the mirror milling process. The file is created by the CNC system during the processing, collecting the workpiece coordinate system coordinate values ​​of each processing point, the coordinate values ​​of the five-axis rotary axis inside and outside the equipment, the wall thickness measurement data and other data, and is generated according to the time index; The processing file used in the present invention is a file collected and generated by the numerical control system of the overall box bottom mirror milling equipment during the processing. The information used includes the coordinate values ​​of the five outer axes X, Y, Z, A, and C on the milling side of the equipment and the five inner axes X2, Y2, Z2, A2, and C2 on the measuring side at each tool position, the position values ​​Px, Py, and Pz in the workpiece coordinate system, and the measured wall thickness value H at the current tool position.

[0015] Step 2: Identify the formal processing points according to the algorithm, calculate the normal vectors and wall thickness line segment lengths of all formal processing points, and define different colors for the line segments according to different wall thickness ranges; The present invention determines whether it is in the formal processing process by comparing whether the coordinate values ​​of the A-axis and C-axis of the outer five axes on the milling side are respectively equal to the coordinate values ​​of the A2-axis and C2-axis of the inner five axes on the measuring side, and excludes the tool position points that are not formal processing points; According to the coordinate values ​​of the A-axis and C-axis of the five external axes on the milling side, the normal vectors Nx, Ny, and Nz of the tool position point are calculated through the homogeneous transformation matrix; Nx=sinCsinA(1) Ny=-cosCsinA(2) Nz=cosA(3) Where Nx, Ny, and Nz are the X, Y, and Z axis components of the tool axis vector of the point, respectively; C and A are the coordinate values ​​of the C and A axes of the five external axes of the point, respectively.

[0016] Read the input theoretical wall thickness value Hm and the set tolerance range DH, and calculate the wall thickness tolerance value Hc=H-Hm at this point; read the input wall thickness tolerance range, determine the tolerance range where Hc is located, and define the color of the wall thickness line at this point according to the range. If Hc<0, set the wall thickness line to red; if 0≤Hc≤DH, set the wall thickness line to light green; if Hc>DH, set the wall thickness line to yellow.

[0017] According to the coordinate values ​​Px, Py, and Pz in the workpiece coordinate system in the process file, they are defined as the starting coordinates Px1, Py1, and Pz1 of the wall thickness line: Px1=Px(4) Py1=Py(5) Pz1=Pz(6) Where Px1, Py1, and Pz1 are the X, Y, and Z axis coordinate values ​​of the starting point coordinates of the wall thickness line, respectively; Px, Py, and Pz are the X, Y, and Z axis coordinate values ​​of the workpiece coordinate system in the process file, respectively.

[0018] Read the input magnification factor K, and calculate the wall thickness line length L as the product of the wall thickness tolerance value and the magnification factor, that is, L=K×Hc; according to the calculated normal vectors Nx, Ny, Nz, the starting coordinates Px, Py, Pz of the wall thickness line and the length L of the wall thickness line, calculate the end coordinates of the wall thickness line: Px2=Px1+Nx×L(7) Py2=Py1+Ny×L(8) Pz2=Pz1+Nz×L(9) Wherein, Px2, Py2, and Pz2 are the end point coordinates of the wall thickness line, Px1, Py1, and Pz1 are the starting point coordinates of the wall thickness line, and L is the length of the wall thickness line.

[0019] Step 3: In the 3D software, draw line segments one by one according to the obtained coordinate values ​​of the formal processing points, normal vector values, wall thickness line length values ​​and colors; The present invention uses the line segment drawing function of the three-dimensional software to draw all the wall thickness lines calculated in the previous step, and respectively mark the colors of the wall thickness lines. After all the wall thickness lines are drawn into the three-dimensional software, a wall thickness display cloud map is formed, which is convenient for intuitively observing the wall thickness distribution and can quickly measure the wall thickness at each tool position. Step 4: Based on the wall thickness information, calculate the proportion of each tolerance range value, determine whether the processing is qualified, and display it in the 3D software in the form of a dialog box.

[0020] The present invention uses an algorithm to count the tolerance distribution information of all wall thickness lines obtained in the previous step in the three-dimensional software. In order to more accurately analyze the wall thickness distribution, the wall thickness tolerance range is counted in 12 grades with 1 / 10 of the wall thickness tolerance DH: <0, 0~0.1DH, 0.1DH~0.2DH, 0.2DH~0.3DH, 0.3DH~0.4DH, 0.4DH~0.5DH, 0.5DH~0.6DH, 0.6DH~0.7DH, 0.7DH~0.8DH, 0.8DH~0.9DH, 0.9DH~DH, >DH, and the number of each grade is calculated respectively. After the statistics are completed, the proportion of the wall thickness tolerance of each grade is calculated, and it is displayed in the form of a dialog box in the three-dimensional software to facilitate the analysis of the processing quality.

[0021] Through the present invention, the wall thickness information of a large amount of more than 100,000 tool position positions can be intuitively and accurately counted and displayed, which greatly improves the quality analysis efficiency and product reliability, and can form a product delivery data package to achieve good data traceability, which plays a significant role in improving the overall box bottom mirror milling processing technology level.

[0022] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for analyzing the quality of mirror milling of an integral box bottom, characterized in that: include: Step 1: Read the processing file during the mirror milling process; Step 2: Identify the formal processing points in the processing process file according to the preset algorithm, calculate the normal vectors and wall thickness line segment lengths of all formal processing points, and define different colors for the wall thickness line segments according to different wall thickness ranges; Step 3: In the 3D software, according to the coordinate value of the formal processing point, the normal vector value, the length value and color of the wall thickness line, draw the wall thickness lines of all formal processing tool positions, and render all the wall thickness lines according to the color; Step 4: According to the wall thickness information, the wall thickness tolerance range of all formal processing tool positions is counted, and the proportion value of the tolerance range is analyzed to determine whether the processing is qualified, and it is displayed in the 3D software in the form of a dialog box.

2. The method for analyzing the quality of the overall bottom mirror milling process according to claim 1 is characterized in that: In step 1, the processing process file includes the coordinate values ​​of the five outer axes X, Y, Z, A, and C on the milling side of the mirror milling equipment and the five inner axes X2, Y2, Z2, A2, and C2 on the measuring side at each tool position, the position values ​​Px, Py, and Pz in the workpiece coordinate system, and the measured wall thickness value H at the current tool position; the processing process file is created and generated according to the time index.

3. The method for analyzing the quality of the mirror milling of the entire bottom of a box according to claim 2 is characterized in that: In step 2, compare whether the coordinate values ​​of the outer five-axis A / C axis and the inner five-axis A2 / C2 axis of the mirror milling equipment are equal. If they are equal, the point is judged to be the formal processing point, otherwise it is the entry and retraction point.

4. The method for analyzing the quality of the mirror milling of the entire bottom of a box according to claim 2 is characterized in that: In step 2, the normal vector value of the formal processing tool position is calculated according to the A / C axis angle value of the mirror milling equipment through homogeneous matrix operation, and the difference between the actual wall thickness and the theoretical wall thickness is calculated according to the theoretical wall thickness value as the wall thickness tolerance of the current tool position. The tool position in the processing process file is used as the starting point of the wall thickness line, and the vector direction, magnification factor and wall thickness tolerance are calculated to obtain the end point of the wall thickness line, and the color of the wall thickness line is set according to the preset wall thickness tolerance range.

5. The method for analyzing the quality of the mirror milling of the entire bottom of a case according to claim 4 is characterized in that: According to the coordinate values ​​of the A-axis and C-axis of the five external axes on the milling side, the normal vectors Nx, Ny, and Nz of the tool position point are calculated through the homogeneous transformation matrix; Nx=sinCsinA(1) Ny=-cosCsinA(2) Nz=cosA(3) Where Nx, Ny, and Nz are the X, Y, and Z axis components of the tool axis vector of the point, respectively; C and A are the coordinate values ​​of the C and A axes of the five external axes of the point, respectively; Read the input theoretical wall thickness value Hm and the set tolerance range DH, and calculate the wall thickness tolerance value Hc=H-Hm at this point; read the input wall thickness tolerance range, determine the tolerance range where Hc is located, and define the color of the wall thickness line at this point according to the range. If Hc<0, set the wall thickness line to the first color; if 0≤Hc≤DH, set the wall thickness line to the second color; if Hc>DH, set the wall thickness line to the third color; According to the coordinate values ​​Px, Py, and Pz in the workpiece coordinate system in the process file, they are defined as the starting coordinates Px1, Py1, and Pz1 of the wall thickness line: Px1=Px(4) Py1=Py(5) Pz1=Pz(6) Where, Px1, Py1, and Pz1 are the X, Y, and Z axis coordinate values ​​of the starting point coordinates of the wall thickness line, respectively; Px, Py, and Pz are the X, Y, and Z axis coordinate values ​​of the workpiece coordinate system in the process file, respectively; Read the input magnification factor K, and calculate the wall thickness line length L as the product of the wall thickness tolerance value and the magnification factor, that is, L=K×Hc; according to the calculated normal vectors Nx, Ny, Nz, the starting coordinates Px, Py, Pz of the wall thickness line and the length L of the wall thickness line, calculate the end coordinates of the wall thickness line: Px2=Px1+Nx×L(7) Py2=Py1+Ny×L(8) Pz2=Pz1+Nz×L(9) Wherein, Px2, Py2, and Pz2 are the end point coordinates of the wall thickness line, Px1, Py1, and Pz1 are the starting point coordinates of the wall thickness line, and L is the length of the wall thickness line.

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