Conical surface machining method based on three-dimensional software programming and application of conical surface machining method

Abstract

The invention discloses a conical surface machining method based on three-dimensional software programming and application of the conical surface machining method. The machining method comprises the steps that a conical surface contour is unfolded, a plane contour tool path is generated, then the plane contour tool path is converted into a plane curve, the plane curve is wound around a conical surface, and the conical surface is machined. And in the three-dimensional software, a wound plane curve is selected in a curve / point driving mode to generate a machining tool path. According to the method, a numerical control program required for machining the conical molded surface of the part is compiled according to a programming thought different from a traditional machining thought, a tool path curve of plane milling is obtained by utilizing a curve winding and unfolding function of three-dimensional programming software, and then the tool path curve is converted into a driving curve required for variable contour milling. The obtained driving curve serves as a machining tool path, the tool path is relatively simple, the number of lifted and lowered tools is small, a large amount of invalid idle tool walking time is saved, and the machining efficiency of the conical surface is improved; a machining tool path converted from a plane milling tool path is small in tool path step pitch and large in tool path number, and a machined conical surface is smooth, good in roughness and excellent in machining quality.

Description

Technical Field

[0001] The invention relates to the technical field of numerical control machining, and in particular to a conical surface machining method based on three-dimensional software programming and an application thereof. Background Art

[0002] When machining a certain type of casing, it is usually necessary to machine the conical surface of the outer wall. The conical surface is as shown in the attached manual. Figure 1 As shown, this profile is usually completed by milling and requires CNC milling programming.

[0003] The conventional CNC programming method for the processing of the tapered surface of the casing is to use the fixed axis processing method in the 3D software for programming. Fixed axis processing programming is to write a processing program to specify the machine tool's motion axis and the tool's moving trajectory according to the workpiece's geometric shape and processing requirements during the process of processing the workpiece on the CNC machine tool to achieve accurate processing of the workpiece. However, for the processing of the tapered surface of the casing, the processing tool path obtained by the fixed axis processing method is as shown in the attached manual. Figure 6 As shown in the figure, it can be seen that the machining tool path is extremely complicated, with many infeed and retract operations. After machining, the bottom surface of the cone is relatively rough, the machining quality is not high, and the machining efficiency is low.

[0004] The patent with publication number CN104690490A discloses a dual-spindle turning and milling compound processing method for aircraft engine casing, including dividing 16 processing areas according to the geometric structure of the casing, selecting a dual-spindle turning and milling compound processing machine tool, determining the type and size of the cutting tool, processing process parameters and tool feeding method, and using UG software and the Post Builder post-processing constructor provided by it to plan the tool path for the dual-spindle to simultaneously process the inner cavity and outer wall of the casing, and convert it into a CNC instruction for seven-coordinate five-linkage dual-spindle simultaneous processing that can be run by the Huazhong CNC HNC-848 control system. The invention can complete the turning and milling compound cutting of complex casings and the simultaneous vertical and horizontal dual-spindle processing with one clamping and positioning, thereby improving processing efficiency and effectively controlling processing deformation, providing an overall solution for the CNC processing of domestic aircraft engine casing parts.

[0005] The above patent mentions the design of the tool path for fine milling of the inner and outer wall surfaces of the casing: in order to ensure machining accuracy, single-spindle machining is adopted for fine milling, horizontal spindle machining is used for fine milling of the outer wall surface, and vertical spindle machining is used for fine milling of the inner wall surface; variable axis surface contour machining is adopted for the casing surface cavity groove, and two driving methods of boundary and outer contour milling are used; fixed axis milling is adopted for the fixed angle boss contour surface of the casing, and curve and surface driving method is used; variable axis surface contour machining is selected for variable angle boss machining, and the driving method is the ruled surface driving method to generate a fine machining tool path; for the tool joint marks, residual materials or large fillets generated between the surfaces due to different tools and different driving methods, variable axis surface contour machining is adopted, and the root cleaning tool path is generated by the boundary driving method, and converted into a tool path file in CLS format.

[0006] Although the above patent involves CNC machining of the outer wall profile of the casing, its technical solution is still similar to the fixed axis machining method, and its description of the outer wall profile machining mainly focuses on achieving simultaneous machining of the inner and outer walls of the casing to shorten the machining time. Therefore, there is still a lack of conical surface machining methods that can effectively reduce ineffective tooling on the market. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a conical surface machining method based on three-dimensional software programming that can improve the machining surface quality and machining efficiency in view of the defects of the prior art.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A conical surface machining method based on three-dimensional software programming, which unfolds the conical surface contour to generate a plane contour tool path, then converts the plane contour tool path into a plane curve, wraps the plane curve onto the conical surface, and selects a driving method in the three-dimensional software to generate a machining tool path for the wrapped plane curve.

[0010] Furthermore, the three-dimensional software is UG.

[0011] Furthermore, the unfolding of the conical surface contour is achieved using the unfolding curve function of UG.

[0012] Furthermore, the generation of plane contour toolpaths is achieved by creating plane milling.

[0013] Furthermore, the conversion of plane contour tool paths into plane curves requires post-processing.

[0014] Furthermore, the post-processing process is: first post-process the plane contour tool path into a .dat format data file, and then import the data file using the UG spline function.

[0015] Furthermore, the winding of the plane curve to the conical surface is achieved by using the winding function of UG.

[0016] Furthermore, the generation of machining tool paths is achieved using UG variable contour milling programming.

[0017] Furthermore, the driving mode is a curve / point driving mode.

[0018] The present invention also provides an application of the conical surface machining method based on UG programming as described above, which is mainly used for machining the conical surface on the casing of an aircraft engine.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention compiles the CNC program required for the processing of the conical surface of parts with a programming idea different from that of traditional processing. Specifically, the curve winding and unfolding function of the three-dimensional programming software in the CNC machine tool is used to obtain the tool path curve of the plane milling, and then convert it into the driving curve required for variable contour milling. The obtained driving curve is used as the processing tool path. The tool path is relatively simple, with less tool lifting and cutting, which can save a lot of invalid tool walking time and significantly improve the processing efficiency of the conical surface. At the same time, the processing tool path converted from the plane milling tool path has a small tool path step distance and a large number of tool paths. The processed conical surface is relatively smooth, with good roughness, and the part processing quality is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the conical surface of the casing according to Embodiment 1 of the present invention;

[0022] Figure 2 This is a schematic diagram of the unfolding of the conical surface profile described in Example 1 of the present invention;

[0023] Figure 3 A schematic diagram of a plane curve converted from the plane contour tool path described in Example 1 of the present invention;

[0024] Figure 4 It is a schematic diagram of winding a plane curve onto a conical surface according to Embodiment 1 of the present invention;

[0025] Figure 5 A schematic diagram of a machining tool path generated in Example 1 of the present invention;

[0026] Figure 6 Schematic diagram of the machining tool path generated for traditional machining of conical surfaces. DETAILED DESCRIPTION

[0027] In order to clearly illustrate the technical features of the present solution, the present technical solution is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0029] In addition, in the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0030] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] In the present application, unless otherwise clearly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0032] Example 1

[0033] This embodiment takes the aircraft engine casing as an example and proposes a processing method based on 3D software programming for the conical surface 1 of the casing outer wall. It mainly uses the curve winding and unfolding function of the 3D software to obtain the tool path curve of the conical surface plane milling, and then converts it into a processing drive curve. Because the "curve / point" to be used in the conventional drive method does not have a ready-made curve to choose from on the casing conical surface model, this processing method needs to create a drive curve. The specific process is as follows:

[0034] 1. Expand the outline of the casing cone surface 1 by using the 3D software of the CNC machine tool: the 3D software in this embodiment is UG, such as Figure 1 The unfolding of the conical surface contour shown is achieved using the unfolding curve function of UG.

[0035] 2. Generate plane contour tool path: Use the unfolded conical surface contour 2 to create plane milling and generate the plane contour tool path.

[0036] 3. Convert the plane contour tool path into a plane curve 3: Convert the plane contour tool path into a plane curve through post-processing Figure 3 The post-processing process of the plane curve 3 shown is: first post-process the plane contour tool path into a .dat format data file, and then import the data file using the UG spline function to obtain plane curve 3.

[0037] 4. Wrap the plane curve 3 onto the conical surface 1 of the casing: Use the winding function of UG to wrap the obtained plane curve onto the conical surface 1, as shown below Figure 4 The winding curve 4 is shown.

[0038] 5. Select the drive mode in UG software to generate the machining path of the conical surface: Use winding curve 4, use UG variable contour milling programming, and select UG's "curve / point" drive mode to generate the following Figure 5 The machining path shown.

[0039] The present invention guides programming through the above-mentioned special processing flow. Compared with the traditional fixed-axis processing programming method, the generated processing tool path for the machine casing conical surface is relatively simple, with less advance and retract tool, which saves a lot of invalid tool walking time and can effectively improve the processing efficiency of the machine casing conical surface.

[0040] The smoothness of the surface processing of the casing conical surface is usually determined by the number of tool paths for processing the curved surface. The smaller the tool path step, the better the surface roughness after processing. The curved surface contour processing tool path finally output by the present invention is actually converted from the plane milling tool path. The number of tool paths can be easily controlled in plane milling. After conversion, the curved surface contour processing tool path is consistent with the plane milling tool path, and the processing part is the same. Therefore, the casing conical surface processed by the present invention is relatively smooth and has high processing quality.

[0041] The processing method of the present invention has been verified by batch processing on a certain type of casing conical surface. The processing path is smooth and stable, and the quality qualification rate of the casing conical surface is 100%.

[0042] The processing method of the present invention is not limited to the processing of aircraft engine casings. As long as the part has a conical surface, the surface milling can be carried out using the above processing method.

[0043] Example 2

[0044] The difference between this embodiment and embodiment 1 is that the three-dimensional software used for the CNC machine tool is Pro / Engineer, and the specific process of generating the machining tool path is consistent with that of embodiment 1.

[0045] Comparative Example 1

[0046] This comparative example compares the patent with publication number CN104690490A with the technical solution of the present invention. The patent proposes a dual-spindle turning and milling compound processing method for an aircraft engine casing, and uses a dual-spindle turning and milling compound processing machine tool to process the aircraft engine casing. The steps related to the conical surface of the casing of the present invention are extracted for comparison:

[0047] Step 4: Use UG software to plan the CNC machining tool path. The specific points are as follows:

[0048] a) Establish the UG / CAM model of the receiver parts: establish the rough machining CAM model and the fine machining CAM model in UG / CAM. The models should include the receiver geometry PART_MODEL and the blank geometry PART_WRK, and combine the two into the UG / CAM model through assembly method;

[0049] b) planning a processing route for rough milling of internal and external surfaces by two spindles simultaneously: the vertical spindle (2) sequentially mills the large end annular cavity groove, T-shaped groove, and small end cylindrical cavity groove of the inner wall of the casing, while the horizontal spindle (3) correspondingly sequentially mills the large end annular cavity groove, the surface between the plum blossom bosses, and the small end cylindrical cavity groove of the outer wall of the casing; a processing route for fine turning of internal and external surfaces by two spindles simultaneously: the vertical spindle (2) sequentially turns the large end conical surface and the small end cylindrical surface of the inner wall of the casing, while the horizontal spindle (3) correspondingly sequentially turns the large end conical surface and the small end cylindrical surface of the outer wall of the casing; a processing route for fine milling of internal and external surfaces: the single spindle fine mills each cavity groove, the boss end face and the side profile, each annular cavity groove connection part, and root cleaning of the internal and external surfaces;

[0050] c) Create tool path files for dual-spindle simultaneous machining of inner and outer wall surfaces: In the UG CAM environment, the variable axis surface drive method in the multi-axis machining mode is used, and the inner and outer surfaces of the casing are selected as the machining geometry. The boss on the outer surface of the casing is selected as the inspection geometry, and the tool axis vector direction is set. The step length of the common coordinate axis C axis is set according to the machining accuracy, and two single-spindle cavity milling tool paths (8) and (9) with fixed step lengths are generated respectively; the Turning machining type of UG can be used to generate two single-spindle torus turning tool paths;

[0051] By setting the common machining projection area and tool direction information, the two generated single-spindle tool paths are trimmed, and the shared coordinate axis C axis is used as the keyword to synthesize the two single-spindle tool path files with C, Y, Z and C, V, W as the coordinate axes into a dual-spindle seven-coordinate five-link CLS tool path file with C, Y, Z, V, W as the coordinate axes.

[0052] d) Design of tool path for fine milling of inner and outer wall surfaces: To ensure machining accuracy, fine milling is performed using a single spindle. The outer wall surface is fine milled using a horizontal spindle (3), while the inner wall surface is fine milled using a vertical spindle (2). The cavity of the casing surface is processed by a variable axis curved surface contour processing method, using two driving methods, boundary and outer contour milling. The fixed angle boss contour of the casing is processed by a fixed axis milling method, using a curve and surface driving method. The variable axis curved surface contour processing method is selected for the variable angle boss processing, and the driving method is a ruled surface driving method, to generate a fine machining tool path. For the tool joint marks, residual materials or large fillets generated between the surfaces due to different tools and different driving methods, a variable axis curved surface contour processing method is used, using a boundary driving method to generate a root cleaning tool path, and the tool path file is converted into a tool path file in the CLS format.

[0053] Compared with the technical solution of Example 1, although this comparative patent also provides a tool path design for processing the outer wall surface of the casing, it does not mention wrapping the unfolded plane around the outer wall surface of the casing again, and the driving method indicated is completely different from that of the present invention.

[0054] Comparative Example 2

[0055] This comparative example compares the patent with publication number CN112643103A and the technical solution of the present invention. The patent proposes a method for processing the triangular cone surface contour of a turbocharger rotor. Through a spiral point processing method, the original axial oblique feed and circumferential arc milling are changed to a three-axis spiral milling method to avoid tool marks when the tool moves axially on the triangular cone hole and shaft surface. The accuracy of the CNC milling machine when walking a straight line segment is higher than the accuracy of the interpolated arc. The arc walking is changed to a straight line segment by cutting the circle, and the processing accuracy is adjusted by adjusting the length of the straight line segment. The three-dimensional model of the triangular cone surface is established using three-dimensional software, and then a spiral curve is drawn on the triangular cone surface as needed, and then the data point coordinates on the spiral line are extracted according to a certain density, and then subsequent programming is performed according to the actual processing machine tool, and the three-axis spiral milling method is used to change the arc walking to a straight line segment by cutting the circle, and the processing accuracy is adjusted by adjusting the length of the straight line segment.

[0056] This patent is aimed at the contour processing of triangular pyramid surfaces. The processing object is similar to the conical surface of the present invention, but its technical solution is completely different from that of the present invention. The purpose of its tool path design is mainly to improve the processing accuracy of the triangular pyramid surface contour, and it does not involve the issue of saving the time of empty cutting through tool path optimization.

[0057] Obviously, the above embodiments are merely examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A conical surface machining method based on three-dimensional software programming, characterized in that: The cone profile is unfolded to generate a plane profile tool path, and then the plane profile tool path is converted into a plane curve. The plane curve is wrapped around the cone profile, and a driving method is selected in the 3D software to generate a processing tool path for the wrapped plane curve.

2. The conical surface machining method based on three-dimensional software programming according to claim 1 is characterized in that: The three-dimensional software is UG.

3. The conical surface machining method based on three-dimensional software programming according to claim 2 is characterized in that: The unfolding of the conical surface contour is achieved using the unfolding curve function of UG.

4. The conical surface machining method based on three-dimensional software programming according to claim 3 is characterized in that: The generation of plane contour toolpath is achieved by creating plane milling.

5. The conical surface machining method based on three-dimensional software programming according to claim 4 is characterized in that: The conversion of plane contour tool paths into plane curves requires post-processing.

6. The conical surface machining method based on three-dimensional software programming according to claim 5, characterized in that: The post-processing process is: first post-process the plane contour tool path into a .dat format data file, and then import the data file using the UG spline function.

7. The conical surface machining method based on three-dimensional software programming according to claim 6 is characterized in that: The winding of the plane curve to the conical surface is achieved using the winding function of UG.

8. The conical surface machining method based on three-dimensional software programming according to claim 7, characterized in that: The generation of machining tool paths is achieved using UG variable contour milling programming.

9. The conical surface machining method based on three-dimensional software programming according to claim 8, characterized in that: The driving mode is a curve / point driving mode.

10. An application of the conical surface machining method based on three-dimensional software programming as claimed in any one of claims 1 to 9, characterized in that: Used for machining conical surfaces of aircraft engine casings.

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