A method for programming a machining coordinate system in reverse

Abstract

The present invention discloses a method for reverse-establishing a machining coordinate system. By applying the program review function in VERICUT software, based on the coordinate positions of special points in the simulation model corresponding to the position relationship of the reference coordinate system in CATIA software, and according to the coordinate system values at this position, a machining coordinate system is reverse-established on the part digital model. If there are no coordinate positions of special points in the simulation model, the simulation model saved in VERICUT software is imported into CATIA software to make the machining coordinate system of the simulation model coincide with the reference coordinate system. Additionally, an assembly file of PRODUCT is created, and the original model and the simulation model are respectively imported. Through corresponding constraint relationships, the simulation model is made to coincide with the original model. Finally, the reference coordinate system is converted to the machining coordinate system of the original model, thus completing the reverse establishment of the machining coordinate system. By using the method of the present invention, the reverse establishment from the program to the machining coordinates is realized, improving the programming efficiency and machining quality, shortening the machining cycle of parts, reducing the enterprise cost, and being suitable for popularization and use.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical control machining and is used for numerical control machining without a programming process. Specifically, it is a method for reverse-constructing a machining coordinate system. Background Art

[0002] For the machining process of numerical control products, it is generally a process from conceptual design to CAD modeling, numerical control programming, numerical control machining, and finally forming a product. In the actual application process, due to the continuous upgrading and modification requirements of aircraft performance, it is required to make corresponding local changes to the components that make up the aircraft. For example, lengthening the end of a component or thickening its wall thickness, etc., all belong to local changes. For such local changes, the current situation is that there is only the machining program before the change, but there is no corresponding numerical control machining programming process. If programming is redone, not only is the programming task heavy, but the workload is also increased. Especially for parts such as large frames and girders, first, the programming time is long, generally taking two weeks or even longer to complete the programming task, which is not only time-consuming but also risky; second, on the original basis, only making local modifications, if the previous program can be utilized, the programming efficiency can be greatly improved, but the key problem is how to ensure that the currently established machining coordinate system is consistent with the originally constructed coordinate system.

[0003] During the design process of all aircraft parts, there is an original starting coordinate, that is, the reference coordinate system, which is the origin of the design of each aircraft part. The relative positions of each part and their positions on the entire aircraft are determined by the reference coordinate system. Therefore, the reference coordinate system is also called the aircraft coordinate system. However, when machining parts, the machining coordinate system is established on or near the part according to the shape and structure of the part. When simulating the machining program in the VERICUT software, the default machining coordinate system is the reference coordinate system in the CATIA software. When importing the simulation model in the VERICUT software into the CATIA software, the machining coordinate system of the simulation model is the reference coordinate system, rather than near the position where the part is located. Therefore, it is necessary to convert the position relationship of the special points of the simulation model in the reference coordinate system to the existing part, and thus it is necessary to establish a machining coordinate system.

[0004] Generally, the method for establishing a machining coordinate system is that its X-axis is selected perpendicular to the rib of the part or perpendicular to the symmetry plane of the part, the Z-axis is selected perpendicular to the web of the part, and the origin of the coordinate system is usually selected at half of the height of the part. Therefore, there are the following three situations for reverse-constructing the coordinate system: one is that there are mutually perpendicular planes on the part, the second is that the part shape is symmetric and there is a symmetric plane, and the third is that there are neither mutually perpendicular planes nor symmetric planes on the part.

[0005] In view of the existing situation where there is only a processing program but no corresponding CNC machining programming process, in order to meet the needs of continuous upgrading and modification of aircraft, improve programming efficiency, and reduce costs, how to make the simulation model in VERICUT software correspond to the reference coordinate system in CATIA software. It is under such a background that a method for reverse construction of the machining coordinate system is proposed to achieve the reverse construction from the program to the machining coordinates. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for constructing a machining coordinate system in view of the problems in the background technology. By using this method, the machining coordinate system in VERICUT software can correspond to the reference coordinate system in CATIA software, realizing the reverse construction from the program to the machining coordinates, thereby improving programming efficiency, reducing costs, and ensuring the machining quality of parts. Specifically, it is a method for reverse construction of the programming machining coordinate system.

[0007] To solve the above technical problem, the technical solution adopted by the present invention is as follows: A method for reverse construction of the programming machining coordinate system, which is to apply the program review function in the CNC machining simulation system VERICUT software to reproduce the trajectory of the existing program. According to the position relationship of the coordinates of special points in the simulation model corresponding to the reference coordinate system in CATIA software, the machining coordinate system is reversely constructed on the part digital model based on the coordinate values at this position; if there are no coordinates of special points in the simulation model, the simulation model saved in VERICUT software is first removed from the connecting lugs and blank residues, and then imported into CATIA software to make the machining coordinate system of the simulation model coincide with the reference coordinate system. A standard small cube is newly created at the reference coordinate system in CATIA software to represent the position and direction of the machining coordinate system. Then, another PRODUCT assembly file is newly created, and the original model and the simulation model are respectively imported. Through the corresponding constraint relationships, the simulation model coincides with the original model. Finally, the reference coordinate system is converted to the machining coordinate system of the original model, thus completing the reverse construction of the machining coordinate system.

[0008] Furthermore, the method for reverse construction of the programming machining coordinate system of the present invention specifically includes the following steps:

[0009] (1) First, use the existing CNC machining simulation system VERICUT software to simulate the existing program, make the machining coordinate system in VERICUT software correspond to the reference coordinate system in CATIA software, and use the program review function in VERICUT software to reproduce the trajectory of the existing program;

[0010] (2) By means of the tool path in the simulation model, if there are special points on the tool path, namely the position coordinates of such points, or parallel to the X-axis of the machining coordinate system in the VERICUT software, or parallel to the Y-axis, then according to the coordinate values at this position in the VERICUT software, subtract or add the machining tool radius, and make a plane in the reverse direction, and the machining coordinate system can be rebuilt on the part digital model;

[0011] (3) If there are no points parallel to the X-axis or Y-axis on the tool path, but it is a symmetric model, then the coordinate values of two symmetric points on the tool path can be queried and the coordinates of the symmetric plane can be calculated; then find this symmetric plane in the actual model and translate the coordinate values of the symmetric plane to construct the coordinate plane;

[0012] (4) If there are no special points parallel to the X-axis or Y-axis on the tool path and there are no two symmetric points, the simulation result model in the VERICUT software can be first removed the connecting lugs and the blank surplus material and then imported into the CATIA software. Saving in the form of a simulation model in the VERICUT software means selecting the CAD-form model for saving in the saved cutting model and selecting the CATIA V5-form model for output in the file type of the output cutting model;

[0013] (5) Then import the simulation model saved in the VERICUT software into the CATIA software. At this time, the machining coordinate system of the simulation model in the VERICUT software coincides with the reference coordinate system in the CATIA software. Taking the positive directions of the X-axis, Y-axis and Z-axis of the reference coordinate system as the edges, build a standard small cube, take the lower left corner of the standard small cube as the origin of the reference coordinate system, and then save it as a PART file;

[0014] (6) In the CATIA software, create a new PRODUCT assembly file, import the original model and the simulation model respectively. In the assembly file, use the constraint relationships of translation, rotation and coincidence to make the saved simulation model coincide with the original model;

[0015] (7) When the cutting model coincides with the original model, the left front lower vertex of the standard small cube on the simulation model is the origin of the machining coordinate system of the original model, and the three edges of the standard small cube, namely the X-axis, Y-axis and Z-axis, are the machining coordinate system. Thus, the rebuilding of the machining coordinate system is completed.

[0016] Adopting the method of reverse - building the programming processing coordinate system according to the present invention, compared with the prior art, its beneficial effects are as follows: By using the program review function in VERICUT software to reproduce the trajectory of the existing program, and combining the simulation of CATIA software and VERICUT software, the processing coordinate system in VERICUT software is made to correspond to the reference coordinate system in CATIA software. Through reverse - building the programming processing coordinate system, the reverse - building from the program to the processing coordinates is realized, which can reduce the workload of repeated programming. Especially for large - scale parts, it can make the supplementary processing or local modification of the parts simple and clear. This method has high accuracy, strong operability, not only improves the programming efficiency and processing quality, but also shortens the processing cycle of the parts and reduces the enterprise cost, and is suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below with reference to the accompanying drawings.

[0018] Figure 1 FIG. is a schematic structural diagram of the simulation model of the part of the present invention in VERICUT software;

[0019] Figure 2 FIG. is a schematic structural diagram of the simulation model of the present invention imported into CATIA software;

[0020] Figure 3 FIG. is a schematic structural diagram of the simulation model and the original model of the present invention imported into CATIA software;

[0021] Figure 4 FIG. is a schematic structural diagram of the coincidence of the simulation model and the original model of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to further illustrate the concept of the present invention, the following will further describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. Both the VERICUT software and the CATIA software are relatively commonly used software in the existing numerical control machining field, and their functions and effects will not be specifically described. In the process of numerical control machining, since the programming process generally first establishes a processing coordinate system, then programs the part with various instructions, and then forms a machining program for the machine tool through the corresponding program and post - processing software. If there is only a machining program without a programming process, when the program needs to be modified, it can only be reprogrammed. If reprogramming, not only is the programming task heavy, but also the workload is increased. Therefore, in order to make full use of the functions of the VERICUT software and the CATIA software, a method of reverse - building the programming processing coordinate system is proposed.

[0023] As Figures 1 to 4As shown in the figure, a method for inverse construction of a machining coordinate system according to the present invention is to apply the program review function in the VERICUT software of the numerical control machining simulation system to reproduce the trajectory of the existing program. According to the coordinate relationship of special points in the simulation model corresponding to the position of the reference coordinate system in the CATIA software, the machining coordinate system is inversely constructed on the part digital model according to the coordinate system values at this position; if there are no coordinates of special points in the simulation model, the simulation model saved in the VERICUT software is first removed from the connecting lugs and blank residues, and then imported into the CATIA software to make the machining coordinate system of the simulation model coincide with the reference coordinate system. A standard small square is newly created at the reference coordinate system of the CATIA software, and the standard small square is used to represent the position and direction of the machining coordinate system. Then, a new PRODUCT assembly file is created, and the original model and the simulation model are imported respectively. Through the corresponding constraint relationship, the simulation model coincides with the original model. Finally, the reference coordinate system is converted to the machining coordinate system of the original model, thus completing the inverse construction of the machining coordinate system. The specific steps are as follows:

[0024] (1) First, use the existing VERICUT software of the numerical control machining simulation system to simulate the existing program, and use the machining coordinate system in the VERICUT software to correspond to the reference coordinate system in the CATIA software. Use the program review function in the VERICUT software to reproduce the trajectory of the existing program;

[0025] (2) Through the tool path in the simulation model, if there are special points on the tool path, that is, the position coordinates of this point, or parallel to the X axis of the machining coordinate system in the VERICUT software, or parallel to the Y axis, then according to the coordinate values at this position in the VERICUT software, subtract or add the machining tool radius, and make a plane in the reverse direction, and the machining coordinate system can be inversely constructed on the part digital model; in the specific application process, taking the case where this point value is parallel to the X axis as an example, if the coordinate value of this point is positive, it means that the position of the coordinate system is in the negative direction of this point. Since the machining trajectory is composed of different positions of the tool center, the size of the tool diameter affects the machining trajectory. If the machining trajectory of a certain point on the part is on the right side of this point, assuming the tool diameter is 20 and the X coordinate of this point is 50, then it means that the value of this point from the machining coordinate system is 40mm (50 - 10), and the coordinate system is in the negative direction of this point. If the machining trajectory of this point is on the left side of this point, then translate 60mm (50 + 10) in the negative direction from this point on the part, which is the position of the coordinate system. Because the machining trajectory is in space and cannot be accurately positioned, only through the specific points on the part can the position of the coordinate system be inferred inversely;

[0026] (3) If there are no points parallel to the X-axis or Y-axis on the tool path, but it is a symmetric model, the coordinate values of two symmetric points on the tool path can be queried, and the coordinates of the symmetric plane can be calculated; then find the symmetric plane in the actual model and translate the coordinate values of the symmetric plane to construct the coordinate plane;

[0027] (4) If there are no special points parallel to the X-axis or Y-axis on the tool path and no two symmetric points, the simulation result model in the VERICUT software can be first removed the connecting lugs and blank residues, and then imported into the CATIA software. In the VERICUT software, it is saved in the form of a simulation model, which means selecting the CAD-form model for saving in the saved cutting model, and selecting the CATIA V5-form model for output in the file type of the output cutting model;

[0028] (5) Then import the simulation model saved in the VERICUT software into the CATIA software. At this time, the machining coordinate system of the simulation model in the VERICUT software coincides with the reference coordinate system in the CATIA software. Using the positive directions of the X-axis, Y-axis, and Z-axis of the reference coordinate system as the edges, build a standard small cube, take the lower left corner of the standard small cube as the origin of the reference coordinate system, and then save it as a PART file;

[0029] (6) In the CATIA software, create a new PRODUCT assembly file, import the original model and the simulation model respectively. In the assembly file, use the constraint relationships of translation, rotation, and coincidence to make the saved simulation model coincide with the original model;

[0030] (7) When the cutting model coincides with the original model, the lower left front vertex of the standard small cube on the simulation model is the origin of the machining coordinate system of the original model. The three edges of the standard small cube, namely the X-axis, Y-axis, and Z-axis, are the machining coordinate system. Thus, the reverse construction of the machining coordinate system is completed.

[0031] Adopting the method of reverse construction of the programming machining coordinate system described in the present invention, using the relationship between the VERICUT software and the CATIA software, constructing a standard small cube in the reference coordinate system, taking the lower left corner of the standard small cube as the origin of the reference coordinate system, importing the original model and the simulation model respectively, and using the corresponding constraint relationships to make the simulation model coincide with the original model, so as to transform the positional relationship of the simulation model in the reference coordinate system to the part. By reverse constructing the machining coordinate system, it can effectively solve the problem in numerical control machining lacking the programming process.

[0032] In summary, by adopting the method of the present invention, the commonly used numerical control software, VERICUT software, is combined with CATIA software. Using the assembly file in CATIA software, through the method of combining with the simulation model of VERICUT software by means of translational, rotational and mating constraint relationships to reverse establish the programming processing coordinate system, it can not only reduce the workload of repeated programming, especially for large parts, but also greatly improve the programming efficiency, making the supplementary processing or local modification of parts simple, clear, accurate and reliable. At the same time, it can also save time and reduce risks. Through this programming method of reverse establishing the programming processing coordinate system, it has high practical value in actual numerical control machining.

[0033] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific embodiments. The above are only the preferred embodiments of the present invention and do not limit the present invention. Any minor modifications, equivalent replacements and improvements made according to the technical solutions of the present invention should be included in the protection scope of the technical solutions of the present invention.

Claims

1. A method for programming a machining coordinate system in reverse, characterized in that: The method is to apply the program review function in the VERICUT software of the numerical control machining simulation system to reproduce the trajectory of the existing program. Based on the coordinates of special points in the simulation model and their positional relationship with the reference coordinate system in the CATIA software, the machining coordinate system is inversely established on the part digital model according to the coordinate system values of the special points. If there are no coordinates of special points in the simulation model, the simulation model saved in the VERICUT software is first removed of connection lugs and blank leftovers, and then imported into the CATIA software to make the machining coordinate system of the simulation model coincide with the reference coordinate system. A standard small cube is created at the reference coordinate system in the CATIA software to represent the position and direction of the machining coordinate system. Then, another PRODUCT assembly file is created, and the original model and the simulation model are imported respectively. Through the corresponding constraint relationships, the simulation model is made to coincide with the original model. Finally, the reference coordinate system is converted to the machining coordinate system of the original model, thus completing the inverse establishment of the machining coordinate system. The method specifically includes the following steps: (1) First, use the existing VERICUT software of the numerical control machining simulation system to simulate the simulation model, make the machining coordinate system in the VERICUT software correspond to the reference coordinate system in the CATIA software, and use the program review function in the VERICUT software to reproduce the trajectory of the existing program. (2) Through the tool path in the simulation model, if there are special points on the tool path, that is, the position coordinates of the special points, or parallel to the X-axis or Y-axis of the machining coordinate system in the VERICUT software, then according to the coordinate values of the special points in the VERICUT software, subtract or add the machining tool radius, and make a reverse plane, and the machining coordinate system is inversely established on the part digital model. (3) If there are no points parallel to the X-axis or Y-axis on the tool path, but it is a symmetric model, query the coordinate values of two symmetric points on the tool path and calculate the coordinates of the symmetric plane. Then find the symmetric plane in the actual model and translate the coordinate values of the symmetric plane to construct the coordinate plane. (4) If there are no special points parallel to the X-axis or Y-axis on the tool path and no two symmetric points, the simulation result model in the VERICUT software is first removed of connection lugs and blank leftovers and saved in the form of a simulation model. (5) Then, the simulation model saved in the VERICUT software is imported into the CATIA software. At this time, the machining coordinate system of the simulation model in the VERICUT software coincides with the reference coordinate system in the CATIA software. A standard small cube is created with the positive directions of the X-axis, Y-axis, and Z-axis of the reference coordinate system as the edges, and the lower left corner of the standard small cube is used as the origin of the reference coordinate system, and then saved as a PART file. (6) In the CATIA software, another PRODUCT assembly file is created, and the original model and the simulation model are imported respectively. In the assembly file, use the constraint relationships of translation, rotation, and coincidence to make the saved simulation model coincide with the original model. (7) After the cutting model coincides with the original model, the lower left front vertex of the standard small square on the simulation model is the origin of the machining coordinate system of the original model. The three prism edges of the standard small square, namely the X-axis, Y-axis, and Z-axis, are the machining coordinate system. Thus, the reverse construction of the machining coordinate system is completed.

2. A method for programming a machining coordinate system in reverse construction according to claim 1, characterized in that: In the step (4), saving in the form of a simulation model in the VERICUT software means selecting the CAD-form model in the saved cutting model for saving and selecting the CATIA V5-form model for outputting the file type of the cutting model.

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