CN103279608B - The fast finding localization method of large complicated part process operation - Google Patents

Abstract

The invention relates to a fast search and positioning method for processing operations of large and complex parts, which belongs to the technical field of CAD/CAPP/CAM. This method is in the CAM environment. First, the user selects the geometric surface F that needs to be searched for processing operations from the part model; constructs the reference plane RF of F: if F is a plane, then RF=F; if F is a curved surface, the least square Multiplication fits F to a plane; constructs a local coordinate system PS with the middle point of RF as the coordinate origin; constructs a mathematical space V for tool position search based on RF in PS; searches all processing operations in the current processing file, and sets the tool Extract the processing operation whose position falls into V, record its name, process and step, and display the tool path at the same time; at this time, the user can select from the searched processing operation list and double-click to open the specified Machining operations are edited. The method solves the problem of cumbersome and low-efficiency machining operations for finding local positions of parts, and is especially suitable for numerical control machining of large structural parts involving a large number of machining operations.

Description

A Quick Finding and Locating Method for Machining Operations of Large and Complicated Parts

technical field

The invention relates to a computer-aided manufacturing technology, in particular to a fast search and positioning method for complex aircraft structural parts processing operations, in particular to a fast search and positioning method for realizing large-scale complex part processing operations by using a math box.

Background technique

At present, with the continuous improvement of market requirements for product performance and manufacturing costs, the structure of parts is developing towards large-scale and complex parts, resulting in increasingly complex parts processing technology. The processing of a part often includes hundreds or thousands of processing operations. There are different types of processing operations, which are distributed in different processes and processes. It is very difficult to find the processing track at a specified local position. When programming and program improvement or optimization, at present, all processing operations can only be roughly browsed through the manual mouse. Find the processing operation of this part by observing whether there is any sign of the tool track on the corresponding part of the model. The search efficiency is extremely low and the workload is heavy. The specific phase status in actual production is as follows:

In the NC programming of large and complex structural parts, there will be multiple processing operations in one processing feature. Since the craftsman cannot accurately judge the processing status of the current position in the process of compiling the local program, it is necessary to check the existing data related to the local position. Due to the large size and complex structure of the existing machining operations, there will be multiple processes in one processing file, and each process will contain several working steps. Each working step will contain hundreds or even thousands of steps. For processing operations, even if the processing operation that needs to be viewed is determined to exist in a certain work step, it is still necessary to manually traverse all the processing operations under the work step during the search process, which has a huge workload and low efficiency; on the other hand, considering After the programming is completed, when the over-cut or under-cut parts are found in the process of verifying the program through simulation, the craftsman often needs to switch from the simulation system back to the CAM system, and find the corresponding processing that causes the above-mentioned processing quality problems in a large number of processing operations. Operation, manual search process is inefficient and heavy workload, and for local parts with multiple processing operations, due to the lack of global tool path view of local positions, the phenomenon of ambiguity often occurs when the program is modified, and the simulation will inevitably continue to make mistakes. At the same time, it may generate new problems.

At present, in the mainstream commercial CAM software, such as CATIA and NX, the search of processing operations is mainly through manually pointing to each processing operation, and observing whether the trajectory of the processing operation falls on the position that needs to be searched. This method is very inefficient. And it is easy to miss. Li Yingguang and others applied for a patent "a method for fast positioning and correspondence between processing features and processing operations", which achieves the purpose of finding and positioning processing operations by matching the model geometry selected by the user with the driving geometric information contained in the processing operation. However, the disadvantages of this method are: (1) Different machining operations have different types of machining drive geometry. For example, some use line drive, some use surface drive, and even point drive. type of geometric information has high requirements for users; (2) In actual production, the driving geometry in many processing operations is artificially created points, lines, and surfaces, so it is often impossible to find matching geometric elements from the model , which limits the generality of the method.

Contents of the invention

The purpose of the present invention is to invent a fast search for the processing operation of large and complex parts based on the math box in order to solve the problems of difficult positioning, time-consuming, labor-intensive and error-prone in the process of CNC machining (programming) of large and complex parts. positioning method.

Technical scheme of the present invention is:

A fast search and positioning method for processing operations of large and complex parts is characterized in that it comprises the following steps:

Step 1: Open the part process model in the CAM environment, the part process model includes the part geometry model, the processing coordinate system, the machine tool, the tool information and the model of the part processing operation;

Step 2: Click on the geometric surface F whose machining track needs to be viewed from the part model;

Step 3: If F is a plane, take it directly as the reference plane RF; if F is a curved surface, use the least square method to fit it into the reference plane RF through the list of boundary points;

Step 4: Construct the reference plane RF local coordinate system PS;

Step 5: Obtain two points P _A1 (x ₁ , y ₁ , z ₁ ) and P _A2 (x ₂ , y ₂ , z ₂ ) of the reference plane RF in the local coordinate system PS, where x ₁ , y ₁ , z ₁ is the minimum value of the reference plane RF in the three directions of X, Y, and Z in the PS coordinate system, and x ₂ , y ₂ , and z ₂ are the maximum values in the three directions of X, Y, and Z in the PS coordinate system;

Step 6: Set the height of the search space V of the three-dimensional mathematical box and construct the search space V;

Step 7: Extract all processing operations in the part processing file and all tool position lists PRL contained in each processing operation;

Step 8: Cycle through all the processing operations in the part process model, record the processing operations where the tool position falls in the search space V of the math box, and record the process and step information of the processing operation;

Step 9: The user selects the required processing operation from the obtained processing operation list according to the requirement.

The specific steps of adopting the least squares method to fit the reference plane RF described are as follows:

a) Let the reference plane RF equation be z=a ₀ x+a ₁ y+a ₂ , where a ₀ , a ₁ , and a ₂ are equation coefficients;

b) According to the n points in the boundary point list PL, (n≥3): (x _i , y _i , z _i ), i=0,1,...,n-1, use the point (x _i ,y _i , z _i ), i=0,1,…,n-1 to fit and calculate the above plane equation, then make:

$S=\underset{i=0}{\overset{\mathrm{no}-1}{\mathrm{\Σ}}}{(a_{0}x+a_1\mathrm{the\; y}+a_2-z)}^2$ minimum.

c) To make S the smallest, it should satisfy: k=0,1,2

Right now: $\left\{\begin{array}{c}\mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)x_i=0\\ \mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i){\mathrm{the\; y}}_i=0\\ \mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)=0\end{array}\right.$

have, $\left\{\begin{array}{c}{a}_0\mathrm{\Σ}{x_i}^2+a_1\mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i+a_2\mathrm{\Σ}{x}_i=\mathrm{\Σ}{x}_i{z}_i\\ a_0\mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i+a_1\mathrm{\Σ}{{\mathrm{the\; y}}_i}^2+a_2\mathrm{\Σ}{\mathrm{the\; y}}_i=\mathrm{\Σ}{\mathrm{the\; y}}_i{z}_i\\ a_0\mathrm{\Σ}{x}_i+a_1\mathrm{\Σ}{\mathrm{the\; y}}_i+a_2\mathrm{no}=\mathrm{\Σ}{z}_i\end{array}\right.$

or, $\left|\begin{array}{ccc}\mathrm{\Σ}{x_i}^2& \mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i& \mathrm{\Σ}{x}_i\\ \mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i& \mathrm{\Σ}{{\mathrm{the\; y}}_i}^2& \mathrm{\Σ}{\mathrm{the\; y}}_i\\ \mathrm{\Σ}{x}_i& \mathrm{\Σ}{\mathrm{the\; y}}_i& \mathrm{no}\end{array}\right|\left(\begin{array}{c}{a}_0\\ a_1\\ a_2\end{array}\right)=\left(\begin{array}{c}\mathrm{\Σ}{x}_i{z}_i\\ \mathrm{\Σ}{\mathrm{the\; y}}_i{z}_i\\ \mathrm{\Σ}{z}_i\end{array}\right)$

Solve the above linear equations to get: a ₀ , a ₁ , a ₂ ;

d) Get the reference plane RF: z=a ₀ x+a ₁ y+a ₂ ;

e) Project n points in the boundary point list PL to the reference plane RF to obtain a new boundary list PL'.

The construction steps of the reference plane RF local coordinate system PS are as follows:

(1) Obtain the geometric midpoint P ₀ of the surface RF as the origin A _O of constructing the local coordinate system;

(2) Obtain the normal direction of the surface RF pointing to the outside of the material. The normal direction is taken as the Z direction of the local coordinate system and the direction determined by the longest adjacent two points on the RF contour is taken as the X-axis direction.

When setting the height of the search space V of the three-dimensional mathematical box and constructing the search space V, in order to complete the search and reduce the size of the space V as much as possible, it is necessary to set the height of V according to the machining allowance and tool parameters. It is to correct the Z value of the point composed of the maximum values in the three directions in the local coordinate system PS. It is known that the tool diameter is D and the machining allowance a, because when the tool is cutting, in the case of side edge cutting, the theoretical position of the tool point should be offset from F along its normal direction pointing out of the material ( D/2+a) mm, so taking L as (D+a) can ensure the integrity of the search results; and for the cutting of the bottom tooth of the tool, the theoretical value of the tool position point is when F points out of the material At the offset amm of the normal direction of L, (D+a) can fully guarantee the integrity of the search results. The coordinates of the corrected P _A2 are P _A3 (x ₂ , y ₂ , z ₂₊ D+a), and the three-dimensional cuboid area with the points P _A1 and P _A3 as diagonal points is the mathematical box search space V. That is to say, the three-dimensional mathematical box search space V is a three-dimensional cuboid area with points P _A1 and P _A3 as diagonal points, P _A3 is the coordinates of P _A2 after correction, and P _A3 (x ₂ , y ₂ , z _{2 +} D+a), D is the diameter of the tool, and a is the machining allowance; because the tool is cutting, in the case of side edge cutting, the theoretical position of the tool point should be along the normal direction of F pointing out of the material It is offset by (D/2+a) mm, so taking (D+a) can ensure the integrity of the search results; and for the cutting of the bottom tooth of the tool, the theoretical value of the tool position point is along its direction The normal direction outside the material is offset by amm, and taking (D+a) can fully guarantee the integrity of the search results.

Beneficial effects of the present invention:

1) The present invention does not depend on specific CAD/CAM platforms, processing operations and processing drive geometry types, and has strong versatility.

2) The calculation speed of the method of the present invention is fast, and all the processing operations of a certain part of the processed part can be quickly obtained.

3) The present invention uniformly selects geometric planes as the basic search unit, which is easy to use.

4) The present invention solves the problem of cumbersome and low-efficiency processing operations for finding the local positions of parts, and is especially suitable for the programming of numerical control processing programs for large-scale structural parts involving a large number of processing operations.

Description of drawings

Fig. 1 is a flow chart of the present invention's fast search and positioning method for processing operations based on a math box.

Fig. 2 shows that in the present invention, the selected geometric surface F is a plane, in the local coordinate system PS by two points P _A1 (x ₁ , y ₁ , z ₁ ) and point P _A3 (x ₂ , y ₂ , z ₂ +L) Schematic diagram of the mathematical box search space V. Among them, x ₁ , y ₁ , z ₁ are the minimum values of F in the three directions of X, Y, and Z in the PS coordinate system, and x ₂ , y ₂ , z ₂ are the three directions of X, Y, and Z in the PS coordinate system. The maximum value in each direction, L is the height of the search space V of the math box, and it is set to (D+a) mm considering engineering applications.

Fig. 3 shows that under the situation that the selected geometrical surface F in the present invention is a curved surface, as shown in the figure, the black solid line part is a curved surface, and the curved surface is first fitted into the plane RF of the dotted line part by the least squares method.

Fig. 4 is a schematic diagram of the mathematical box search space V constructed by two points on the fitting plane reference plane RF. Construct a local coordinate system PS at RF, where the normal direction pointing to the outside of the material is the Z-axis direction. Considering the engineering application, the X-axis direction is the direction determined by the longest adjacent two points on the RF contour, and the Y-axis direction is according to the right-hand law Sure. Obtain the point P _A1 (x ₁ , y ₁ , z ₁ ) and point P _A2 (x ₂ , y ₂ , z ₂ ) of RF in the local coordinates PS, where x ₁ , y ₁ , z ₁ are RF in PS The minimum value in the three directions of X, Y, and Z in the coordinate system, x ₂ , y ₂ , and z ₂ are the maximum values in the three directions of X, Y, and Z in the PS coordinate system, and L is the height of the search space V of the math box , considering the engineering application, its theoretical value is (D+a) mm.

Fig. 5 is a schematic diagram of searching the processing operation process through the created math box search space V. Among them, the cuboid with P ₁ P ₂ as the diagonal point represents the constructed mathematical box search space V, and the black dots represent the tool points contained in one or more machining operations. If a certain tool point is located in the mathematical box search space In V, it indicates that the processing operation to which the tool position belongs is the object of search.

Fig. 6 is a schematic diagram of the combination of practical application and mathematical box search space V theory. The thin solid line in the figure represents the machining tool path, the black solid point on the path is the tool position point, the thick dotted line frame represents the virtual mathematical box search space V constructed, and the white coordinate system located at the center of the bottom surface of the cavity is the local coordinate system PS, the white solid circle P represents the penultimate tool point on the tool path, P ₁ , P ₂ and P ₃ are the three key points for constructing the mathematical box search space V, and the distance between P ₂ and P ₃ The distance is the height L of the search space, which is (D+a) mm.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1-6.

A fast search and positioning method for large and complex part processing operations, as shown in Figure 1, it includes the following steps:

Step 1: Open the part process model in the CAM environment. The part process model refers to the model that includes the part geometry model, the processing coordinate system, the machine tool, the cutting tool and other information, as well as the part processing operation.

Step 2: From the part model, click the geometric surface F whose machining track needs to be viewed.

Step 3: If F is a plane, take it directly as the reference plane RF; if F is a curved surface, use least squares

The method fits it to the reference plane plane RF through the list of boundary points.

The specific steps of using the least squares method to fit the plane are as follows:

a) Let the reference plane RF equation be z=a ₀ x+a ₁ y+a ₂ , where a ₀ , a ₁ , and a ₂ are equation coefficients.

b) According to the n points in the boundary point list PL, (n≥3): (x _i , y _i , z _i ), i=0,1,...,n-1, use the point (x _i ,y _i , z _i ), i=0,1,…,n-1 to fit and calculate the above plane equation, then make:

$S=\underset{i=0}{\overset{\mathrm{no}-1}{\mathrm{\Σ}}}{(a_{0}x+a_1\mathrm{the\; y}+a_2-z)}^2$ minimum.

c) To make S the smallest, it should satisfy: k=0,1,2

Right now: $\left\{\begin{array}{c}\mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)x_i=0\\ \mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i){\mathrm{the\; y}}_i=0\\ \mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)=0\end{array}\right.$

have, $\left\{\begin{array}{c}{a}_0\mathrm{\Σ}{x_i}^2+a_1\mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i+a_2\mathrm{\Σ}{x}_i=\mathrm{\Σ}{x}_i{z}_i\\ a_0\mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i+a_1\mathrm{\Σ}{{\mathrm{the\; y}}_i}^2+a_2\mathrm{\Σ}{\mathrm{the\; y}}_i=\mathrm{\Σ}{\mathrm{the\; y}}_i{z}_i\\ a_0\mathrm{\Σ}{x}_i+a_1\mathrm{\Σ}{\mathrm{the\; y}}_i+a_2\mathrm{no}=\mathrm{\Σ}{z}_i\end{array}\right.$

or, $\left|\begin{array}{ccc}\mathrm{\Σ}{x_i}^2& \mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i& \mathrm{\Σ}{x}_i\\ \mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i& \mathrm{\Σ}{{\mathrm{the\; y}}_i}^2& \mathrm{\Σ}{\mathrm{the\; y}}_i\\ \mathrm{\Σ}{x}_i& \mathrm{\Σ}{\mathrm{the\; y}}_i& \mathrm{no}\end{array}\right|\left(\begin{array}{c}{a}_0\\ a_1\\ a_2\end{array}\right)=\left(\begin{array}{c}\mathrm{\Σ}{x}_i{z}_i\\ \mathrm{\Σ}{\mathrm{the\; y}}_i{z}_i\\ \mathrm{\Σ}{z}_i\end{array}\right)$

Solve the above linear equations to get: a ₀ , a ₁ , a ₂ .

d) The reference plane RF is obtained: z=a ₀ x+a ₁ y+a ₂ .

e) Project n points in the boundary point list PL to the reference plane RF to obtain a new boundary list PL'. Step 4: Construct the reference plane RF local coordinate system PS. The construction steps are as follows:

(1) Obtain the geometric midpoint P ₀ of the surface RF as the origin A _O of constructing the local coordinate system;

(2) Obtain the normal direction of the surface RF pointing to the outside of the material, which is used as the Z direction of the local coordinate system: considering the practical application of engineering, the direction determined by the longest adjacent two points on the RF contour is used as the X-axis direction .

Step 5: Obtain two points P _A1 (x ₁ , y ₁ , z ₁ ) and P _A2 (x ₂ , y ₂ , z ₂ ) in the local coordinate system PS on RF, where x ₁ , y ₁ , z ₁ are the minimum values of RF in the X, Y, and Z directions of the PS coordinate system, and x ₂ , y ₂ , and z ₂ are the maximum values in the X, Y, and Z directions of the PS coordinate system, respectively.

Step 6: Set the height of the search space V of the three-dimensional mathematical box and construct the search space V. In order to complete the search and reduce the size of the space V as much as possible, it is necessary to set the height of V according to the machining allowance and tool parameters. The Z value is corrected. It is known that the tool diameter is D and the machining allowance a, because when the tool is cutting, in the case of side edge cutting, the theoretical position of the tool point should be offset from F along its normal direction pointing out of the material ( D/2+a) mm, so taking L as (D+a) can ensure the integrity of the search results; and for the cutting of the bottom tooth of the tool, the theoretical value of the tool position point is when F points out of the material At the offset amm of the normal direction of L, (D+a) can fully guarantee the integrity of the search results. The coordinates of the corrected P _A2 are P _A3 (x ₂ , y ₂ , z ₂₊ D+a), and the three-dimensional cuboid area with the points P _A1 and P _A3 as diagonal points is the mathematical box search space V.

Step 7: Extract all processing operations in the part processing file and all tool location lists PRL contained in each processing operation.

Step 8: Cycle through all the processing operations in the part process model, record the processing operations whose tool positions fall in the search space V of the math box, and record the process and step information of the processing operations.

Step 9: The user selects the required processing operation from the obtained processing operation list according to the requirement.

It can be seen from the above that the essence of the present invention is to use the geometric surface on the model as an input condition, and obtain two special point coordinates in the local coordinate system of the plane after fitting the plane or the curved surface, considering the practical application of engineering In this case, construct a mathematical box search space V, judge whether there is a situation that the tool position falls in the search space V in each processing operation in a traversal manner, and if it exists, the tool path will be displayed on the screen and its record will be saved, and at the same time Record the process and step information it is in, and display it in the dialog box together, as the reference information for the user to select and locate, and realize double-clicking to open an operation that can be modified and other operations for the user to click on the operation set found .

The specific process of constructing the math box search space V and the search operation of the present invention is shown in Figure 2, Figure 3, Figure 4, and Figure 5, and is described in detail as follows:

1) When the geometric surface F on the selected model is a plane, as shown in Figure 2, the coordinates of its geometric center point under the current machining coordinates can be obtained, and this coordinate is used as the origin A _o of the local coordinate system, pointing to the plane F The outer normal direction of the material is taken as the Z-axis direction, and the direction determined by the two longest points on the F contour is taken as the X-axis direction, and the X-axis direction and the Z-axis direction are determined according to the right-hand rule of the Cartesian coordinate system to determine the Y-axis direction, so that Determine the local coordinate system PS.

2) When the geometric surface F on the selected model is a curved surface, as shown in Figure 3 and Figure 4, first use the least square method to fit the curved surface into a plane RF, and obtain the geometric center point coordinates of RF under the current processing coordinates, This coordinate is taken as the origin A _o of the local coordinate system, and the normal direction of the RF pointing to the outside of the material is taken as the Z-axis direction. Considering engineering applications, the direction determined by the longest adjacent two points on the RF contour is taken as the X-axis direction. The directions of the X and Z axes determine the direction of the Y axis according to the right-hand rule of the Cartesian coordinate system, thereby determining the local coordinate system PS.

The specific steps of using the least squares method to fit the plane are as follows:

a) Let the reference plane RF equation be z=a ₀ x+a ₁ y+a ₂ , where a ₀ , a ₁ , and a ₂ are equation coefficients.

b) According to the n points in the boundary point list PL, (n≥3): (x _i , y _i , z _i ), i=0,1,...,n-1, use the point (x _i ,y _i , z _i ), i=0,1,…,n-1 to fit and calculate the above plane equation, then make:

$S=\underset{i=0}{\overset{\mathrm{no}-1}{\mathrm{\Σ}}}{(a_{0}x+a_1\mathrm{the\; y}+a_2-z)}^2$ minimum.

c) To make S the smallest, it should satisfy: k=0,1,2

Right now: $\left\{\begin{array}{c}\mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)x_i=0\\ \mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i){\mathrm{the\; y}}_i=0\\ \mathrm{\Σ}2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)=0\end{array}\right.$

have, $\left\{\begin{array}{c}{a}_0\mathrm{\Σ}{x_i}^2+a_1\mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i+a_2\mathrm{\Σ}{x}_i=\mathrm{\Σ}{x}_i{z}_i\\ a_0\mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i+a_1\mathrm{\Σ}{{\mathrm{the\; y}}_i}^2+a_2\mathrm{\Σ}{\mathrm{the\; y}}_i=\mathrm{\Σ}{\mathrm{the\; y}}_i{z}_i\\ a_0\mathrm{\Σ}{x}_i+a_1\mathrm{\Σ}{\mathrm{the\; y}}_i+a_2\mathrm{no}=\mathrm{\Σ}{z}_i\end{array}\right.$

or, $\left|\begin{array}{ccc}\mathrm{\Σ}{x_i}^2& \mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i& \mathrm{\Σ}{x}_i\\ \mathrm{\Σ}{x}_i{\mathrm{the\; y}}_i& \mathrm{\Σ}{{\mathrm{the\; y}}_i}^2& \mathrm{\Σ}{\mathrm{the\; y}}_i\\ \mathrm{\Σ}{x}_i& \mathrm{\Σ}{\mathrm{the\; y}}_i& \mathrm{no}\end{array}\right|\left(\begin{array}{c}{a}_0\\ a_1\\ a_2\end{array}\right)=\left(\begin{array}{c}\mathrm{\Σ}{x}_i{z}_i\\ \mathrm{\Σ}{\mathrm{the\; y}}_i{z}_i\\ \mathrm{\Σ}{z}_i\end{array}\right)$

Solve the above linear equations to get: a ₀ , a ₁ , a ₂ .

d) The reference plane RF is obtained: z=a ₀ x+a ₁ y+a ₂ .

e) Project n points in the boundary point list PL to the reference plane RF to obtain a new boundary list PL'.

3) Obtain P _A1 (x ₁ , y ₁ , z ₁ ) and P _A2 (x ₂ , y ₂ , z ₂ ) of the RF plane in the local coordinate PS, where x ₁ , y ₁ , z ₁ are the RF plane The minimum value in the three directions of X, Y, and Z in the PS coordinate system, and x ₂ , y ₂ , and z ₂ are the maximum values in the three directions of X, Y, and Z in the PS coordinate system.

4) Considering the practical application of engineering, the height of the math box search space V is set to (D+a) mm, thus obtaining the other diagonal point P _A3 (x ₂ ,y ₂ ,z ₂ +D+ a), Construct a mathematical box search space V from P _A1 and P _A3 , V=Box(P _A1 , P _A3 ).

5) Get all the processing operations ListOp in the processing file, ListOp={P ₁ ,P ₂ ,P ₃ ......P _n },n∈N ^* .

6) Obtain the coordinates P _x (y) of the tool position in a certain processing operation, x represents the serial number of the processing operation, and y is the serial number of the tool position in the xth processing operation.

7) If the coordinate value of a certain tool position exists in the constructed mathematical box search space V, the operation meets the search conditions; P _x (y)∈V, and the processing operation set ReOpList that meets the conditions is obtained.

As shown in Figure 6, the coordinates of point P ₁ in the local coordinate system are (41, 25.5, 0), the coordinates of point P ₂ are (-41, -25.5, 0), and the coordinates of point P ₃ are (x ₂ , y ₂ , z ₂ +D+a), where the tool diameter is 20mm, and the machining allowance is 0mm, so the coordinates of P ₃ are (-41, -25.5, 20), and the search space represented by the thick dashed line is V=Box(P ₁ , P ₃ ), as shown in the figure, there are a large number of tool positions falling into V, and the penultimate tool position represented by the red solid circle P has the coordinates of P _x (2) (26.5, 10,0) due to P _x (2) ∈ V, so the processing operation meets the search conditions.

8) Click any processing operation in ReOpList to display the tool path, so as to achieve a clear effect.

9) The above is the process of quickly searching and locating the processing operations based on the math box. Finally, the user selects the required processing operations from the obtained processing operation list according to the needs, and double-clicks to open these processing operations to perform parameter modification and other operations.

The parts not involved in the present invention are the same as the prior art or can be realized by adopting the prior art.

Claims (4)

1. A fast search and location method for large and complex part processing operations, characterized in that it comprises the following steps: Step 1: Open the part process model in the CAM environment, the part process model includes the part geometry model, the processing coordinate system, the machine tool, the tool information and the model of the part processing operation; Step 2: Click on the geometric surface F whose machining track needs to be viewed from the part model; Step 3: If F is a plane, take it directly as the reference plane RF; if F is a curved surface, use the least square method to fit it into the reference plane RF through the list of boundary points; Step 4: Construct the reference plane RF local coordinate system PS; Step 5: Obtain two points P _A1 (x ₁ ,y ₁ ,z ₁ ) and P _A2 (x ₂ ,y ₂ ,z ₂ ) of the reference plane RF in the local coordinate system PS, where x ₁ ,y ₁ ,z ₁ is the minimum value of the reference plane RF in the three directions of X, Y, and Z in the PS coordinate system, and x ₂ , y ₂ , and z ₂ are the maximum values in the three directions of X, Y, and Z in the PS coordinate system; Step 6: Set the height of the search space V of the three-dimensional mathematical box and construct the search space V; Step 7: Extract all processing operations in the part processing file and all tool position lists PRL contained in each processing operation; Step 8: Cycle through all the processing operations in the part process model, record the processing operations where the tool position falls in the search space V of the math box, and record the process and step information of the processing operation; Step 9: The user selects the required processing operation from the obtained processing operation list according to the requirement. 2. according to claim 1, the fast search and positioning method of large complex parts processing operation is characterized in that the specific steps of adopting the least squares method to fit the reference plane RF are as follows: a) Let the reference plane RF equation be z=a ₀ x+a ₁ y+a ₂ , where a ₀ , a ₁ , and a ₂ are equation coefficients; b) According to the n points in the boundary point list PL, n≥3: (x _i , y _i , _zi ), i=0, 1,..., n-1, the point ( _xi , y _i , z _i ), i=0,1,...,n-1 to fit and calculate the above plane equation, then make: $S=\underset{i=0}{\overset{\mathrm{no}-1}{\Σ}}{(a_{0}x+a_1\mathrm{the\; y}+a_2-z)}^2$ minimum; c) To make S the smallest, it should satisfy: Right now: $\left\{\begin{array}{c}\Σ2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)x_i=0\\ \Σ2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i){\mathrm{the\; y}}_i=0\\ \Σ2(a_0{x}_i+a_1{\mathrm{the\; y}}_i+a_2-z_i)=0\end{array}\right.$ have, $\left\{\begin{array}{c}{a}_0{{\mathrm{\Σx}}_i}^2+a_1{\mathrm{\Σx}}_i{\mathrm{the\; y}}_i+a_2{\mathrm{\Σx}}_i={\mathrm{\Σx}}_i{z}_i\\ a_0{\mathrm{\Σx}}_i{\mathrm{the\; y}}_i+a_1{{\mathrm{\Σy}}_i}^2+a_2{\mathrm{\Σy}}_i={\mathrm{\Σy}}_i{z}_i\\ a_0{\mathrm{\Σx}}_i+a_1{\mathrm{\Σy}}_i+a_2\mathrm{no}={\mathrm{\Σz}}_i\end{array}\right.$ or, $\left|\begin{array}{ccc}\Σ{x_i}^2& \Σx_i{\mathrm{the\; y}}_i& \Σx_i\\ \Σx_i{\mathrm{the\; y}}_i& \Σ{{\mathrm{the\; y}}_i}^2& \Σ{\mathrm{the\; y}}_i\\ \Σx_i& \Σ{\mathrm{the\; y}}_i& \mathrm{no}\end{array}\right|\left(\begin{array}{c}{a}_0\\ a_1\\ a_2\end{array}\right)=\left(\begin{array}{c}\Σx_i{z}_i\\ \Σ{\mathrm{the\; y}}_i{z}_i\\ \Σz_i\end{array}\right)$ Solve the above linear equations to get: a ₀ , a ₁ , a ₂ ; d) Get the reference plane RF: z=a ₀ x+a ₁ y+a ₂ ; e) Project n points in the boundary point list PL to the reference plane RF to obtain a new boundary list PL'. 3. The fast search and positioning method of large and complex part processing operations according to claim 1, wherein the construction steps of the described reference plane RF local coordinate system PS are as follows: (1) Obtain the geometric midpoint P ₀ of the surface RF as the origin A _O of constructing the local coordinate system; (2) Obtain the normal direction of the surface RF pointing to the outside of the material, the normal direction is taken as the Z direction of the local coordinate system and the direction determined by the longest connecting two adjacent points on the RF contour is taken as the X-axis direction. 4. The fast search and positioning method for large and complex part processing operations according to claim 1, wherein the three-dimensional mathematical box search space V is a three-dimensional cuboid region with points P _A1 and P _A3 as diagonal points, P _A3 is the coordinate of the modified P _A2 , P _A3 (x ₂ , y ₂ , z ₂₊ D+a), D is the diameter of the tool, and a is the machining allowance; because when the tool is cutting, the side edge of the tool is cut In the case of , the theoretical position of the tool point should be at the offset (D/2+a)mm of F along its normal direction pointing out of the material, so taking (D+a) can ensure the integrity of the search results ; In the case of tool bottom tooth cutting, the theoretical value of the tool position point is at the offset amm along its normal direction pointing out of the material, and taking (D+a) can fully guarantee the integrity of the search results.