Optical processing numerical control program generation method of inclined shaft system numerical control machine tool

Abstract

The invention relates to the technical field of optical machining, in particular to an optical machining numerical control program generation method of an inclined shaft system numerical control machine tool, which comprises the following steps of: establishing a tool coordinate system of a machining tool on the inclined shaft system numerical control machine tool according to a position shaft coordinate system and a posture rotating shaft coordinate system of the inclined shaft system numerical control machine tool; obtaining a surface shape residual error and removal function distribution of the optical element according to the surface shape and the processing technology of the optical element to be processed; determining a processing track of the optical element, and determining an ideal residence point and residence time of the processed optical element in combination with the surface shape residual error and removal function distribution; according to the tool coordinate system, a posture axis coordinate system of the inclined axis numerical control machine tool and the surface shape, the posture of the machining tool during machining is determined; and according to the attitude, the ideal residence point and the residence time, determining a processing program of the processed optical element. The problem that the numerical control program of the inclined shafting numerical control machine tool is difficult to generate is standardized and processed, and good code generation practicability is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical processing, and particularly relates to a method for generating an optical processing numerical control program for an inclined-axis numerical control machine tool. Background Art

[0002] Existing machine tools mostly adopt a standard axis system configuration, such as position axes XYZ and attitude axes ABC that rotate around XYZ. Such an axis system configuration is relatively simple to program in optical processing applications, and the technology is already very mature. If the workpiece to be processed is a curved surface with a very high slope, mechanical interference will occur when a standard machine tool with a standard axis system processes it. To avoid mechanical interference, there are also some applications of inclined-bed numerical control machine tools on the market. The plane where the guide rail is located intersects with the ground plane to form an inclined plane, which can effectively utilize space, greatly reduce the floor area of the machine tool on the plane, facilitate chip removal, and can arrange more tool positions, and it has played a good role in the production of complex parts. However, for large-aperture optical elements, the support structure of the inclined-bed object platform poses a huge challenge to the optical elements. In order to utilize the characteristics of the inclined platform, an inclined-axis numerical control machine tool is used to handle the polishing task of large-aperture optical elements. Its characteristic is that the object platform is horizontal and the tool is inclined, so one or several attitude axes need to be offset to make it have a greater tool freedom. However, for an inclined-axis numerical control machine tool, the difficulty of writing machining codes has increased significantly because key issues such as coordinate changes need to be considered. Summary of the Invention

[0003] In view of this, the present invention aims to provide a method for generating an optical processing numerical control program for an inclined-axis numerical control machine tool, to determine the surface shape of the optical element, determine the ideal dwell point position during polishing, calculate the dwell time corresponding to the ideal dwell point; calculate the attitude of the polishing dwell point, and generate a numerical control machine tool file executed by the inclined-axis numerical control machine tool.

[0004] To achieve the above object, the technical solution of the present invention is realized as follows: A method for generating an optical processing numerical control program for an inclined-axis numerical control machine tool includes: S1: Establish a tool coordinate system of the processing tool on the inclined-axis numerical control machine tool according to the position axis coordinate system and the attitude rotation axis coordinate system of the inclined-axis numerical control machine tool; S2: Obtain the surface shape residual and the removal function distribution of the optical element according to the surface shape and processing technology of the optical element to be processed; S3: Determine the processing trajectory of the optical element, and combine the surface shape residual and the removal function distribution obtained in step S2 to determine the ideal dwell point and dwell time for processing the optical element; S4: Determine the attitude of the processing tool during processing according to the tool coordinate system in step S1, the attitude axis coordinate system of the inclined-axis numerical control machine tool, and the surface shape; S5: Determine the processing program for the optical element according to the attitude obtained in step S4 and the ideal dwell points and dwell times obtained in step S3.

[0005] Further, in step S1, the origin of the attitude rotation axis coordinate system coincides with the origin of the tool coordinate system, and the axis directions of the tool coordinate system are the same as those of the position axis coordinate system.

[0006] Further, in step S3: Determine the ideal dwell points according to the processing trajectory and surface shape; Calculate the dwell time through the following formula: ; where, e i = E(x i , y i , z i ), r ij = R j (x i - ε j , y i - η j , z i - γ j ), t j = T(ε j , η j , γ j ), E(x i , y i , z i ) represents the surface shape residual of the i-th surface shape point (x i , y i , z i ), 1 ≤ i ≤ I, I represents the total number of surface shape points (x i , y i , z i ), R j (x i - ε j , y i - η j , z i - γ j ) represents the removal function distribution at the j-th ideal dwell point (ε j , η j , γ j ), T(ε j , η j , γ j ) represents the dwell time of the j-th ideal dwell point (ε j , η j , γ j ), 1 ≤ j ≤ J, J represents the ideal dwell points (ε j , η j , γj ) total number.

[0007] Further, in step S4: Obtain the coordinate transformation operator between the tool coordinate system and the attitude axis coordinate system; Calculate the marked points on the ideal tool working range of the processing tool where the surface normal of the surface is consistent with the surface normal of the surface shape; Transform the marked points into attitudes through the coordinate transformation operator.

[0008] Further, in step S5: The ideal dwell point is the position of the machining point in the machining program; The attitude is the attitude of the processing tool at the corresponding machining point described in the machining program when machining; Calculate the displacement between two ideal dwell points, and obtain the machining feed rate in the machining program according to the displacement and the dwell time.

[0009] Further, the position of the machining point is the coordinate of the machining point in the position axis coordinate system, the attitude is the coordinate of the processing tool in the attitude axis coordinate system, and the machining feed rate is the feed rate of the processing tool in the position axis coordinate system.

[0010] Compared with the prior art, the present invention can achieve the following beneficial effects: The method for generating an optical machining numerical control program for an inclined axis numerical control machine tool according to the present invention can be applied to the polishing of complex curved surfaces in ultra-precision polishing, consider the code generation process of any inclined axis numerical control machine tool, and the reliability of the code generation strategy is relatively high. The proposal of the present invention solves the problem of machine tool code generation for inclined axis numerical control machine tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a schematic flow chart of the method for generating an optical machining numerical control program for an inclined axis numerical control machine tool according to an embodiment of the present invention; Figure 2 is a schematic diagram of the relative position relationship between the position axis coordinate system and the attitude rotation axis coordinate system according to an embodiment of the present invention; Figure 3 is a schematic diagram of the position relationship between the attitude rotation axis coordinate system and the end position of the processing tool according to an embodiment of the present invention; Figure 4 is a schematic diagram of the position relationship between the tool coordinate system and the attitude rotation axis coordinate system according to an embodiment of the present invention; Figure 5 is a schematic diagram of the relationship between the attitude rotation axis coordinate system and the attitude axis coordinate system of a non-standard five-axis machine tool according to an embodiment of the present invention; Figure 6Schematic diagram of the configuration of the attitude rotation axis in the non-standard five-axis machine tool according to the embodiments of the present invention; Figure 7 Surface residual error diagram according to the embodiments of the present invention; Figure 8 Removal function distribution diagram according to the embodiments of the present invention; Figure 9 Dwell time distribution diagram according to the embodiments of the present invention; Figure 10 Example diagram of a partial machining program according to the embodiments of the present invention. Detailed implementation manners

[0012] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0013] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0014] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention 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 should not be construed as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0015] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0016] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0017] As Figures 1 to 4 shown, the method for generating an optical machining numerical control program for an inclined-axis numerical control machine tool according to an embodiment of the present invention includes: S1: Establish a tool coordinate system for the machining tool on the inclined-axis numerical control machine tool according to the position axis coordinate system and the attitude rotation axis coordinate system of the inclined-axis numerical control machine tool.

[0018] In some embodiments, the origin of the attitude rotation axis coordinate system coincides with the origin of the tool coordinate system, and the axis directions of the tool coordinate system are the same as those of the position axis coordinate system.

[0019] The attitude axis in the inclined-axis numerical control machine tool usually has a rotational function. Specifically, the attitude axis rotates around the attitude rotation axis where the attitude axis is located; for a non-standard six-axis machine tool in the inclined-axis numerical control machine tool, the attitude axis coordinate system of its non-standard attitude axis is defined as UWV. Correspondingly, the attitude of the machining tool during machining is expressed as (U, W, V). For a non-standard five-axis machine tool in the inclined-axis numerical control machine tool, the attitude axis coordinate system of its non-standard attitude axis is defined as WV. Correspondingly, the attitude of the machining tool during machining is expressed as (W, V). In a certain embodiment, the position axis coordinate system of the inclined-axis numerical control machine tool is defined as XYZ, as Figure 2 shown in (a) of r Y r Z r ; the attitude rotation axis coordinate system of the inclined-axis numerical control machine tool is defined as X Figure 2 Y r Z r Z r r Y r Z r r r Figure 2 shown in (b) of Figure 3 ; taking a non-standard six-axis machine tool as an example, during the machining process, the U attitude axis, the W attitude axis, and the V attitude axis in the attitude axis coordinate system respectively rotate around the X Figure 2 axis, the Y Figure 3 axis, and the Z r axis, the Y r axis, and the Z r axis in the attitude rotation axis coordinate system X r Y Figure 4As shown, the attitude rotation axis coordinate system X r Y r Z r The origin O r is the origin O of the tool coordinate system X'Y'Z'. T They coincide, and the axis directions of the tool coordinate system X'Y'Z' are the same as those of the position axis coordinate system XYZ.

[0020] S2: According to the surface shape and processing technology of the optical element to be processed, obtain the surface shape residual and removal function distribution of the optical element.

[0021] In some embodiments, the surface shape of the optical element is measured by an interferometer to obtain the surface shape residual of the optical element. According to the processing technology of the workpiece to be processed, the removal function distribution is determined. The present invention is not limited to one process and may be other deterministic polishing processes such as ion beam figuring and bladder polishing.

[0022] S3: Determine the processing trajectory of the optical element, and combine the surface shape residual and removal function distribution obtained in step S2 to determine the ideal dwell point and dwell time for processing the optical element.

[0023] In some embodiments, the ideal dwell point is determined according to the processing trajectory and surface shape.

[0024] The dwell time is calculated by the following formula: ; where, e i =E(x i ,y i ,z i ), r ij =R j (x i -ε j ,y i -η j ,z i -γ j ), t j =T(ε j ,η j ,γ j ), E(x i ,y i ,z i ) represents the surface shape residual of the i-th surface shape point (x i ,y i ,z i ), 1 ≤ i ≤ I, I represents the total number of surface shape points (x i ,y i ,z i ), R j (x i -ε j ,yi -η j , z i -γ j ) represents removing the removal function distribution at the j-th ideal stationary point (ε j , η j , γ j ). The removal function distribution at the j-th ideal stationary point (ε j , η j , γ j ) is represented by T(ε j , η j , γ j ), and the dwell time of the j-th ideal stationary point (ε j , η j , γ j ) is represented by 1 ≤ j ≤ J, where J represents the total number of ideal stationary points (ε

[0025] S4: Determine the posture of the machining tool during machining according to the tool coordinate system in step S1, the posture axis coordinate system of the inclined-axis CNC machine tool, and the surface shape of the optical element.

[0026] In some embodiments, step S4 includes: obtaining the coordinate transformation operator between the tool coordinate system and the posture axis coordinate system; calculating the marked points where the surface normal on the ideal tool scope of the machining tool is consistent with the surface normal of the surface shape; and transforming the marked points into postures through the coordinate transformation operator.

[0027] S5: Determine the machining program for machining the optical element according to the posture obtained in step S4 and the ideal stationary points and dwell times obtained in step S3.

[0028] In some embodiments, step S5 includes: the position of the ideal stationary point is the position of the machining point in the machining program; the posture is the posture of the machining tool at the corresponding machining point during machining described in the machining program; calculate the displacement between two ideal stationary points, and obtain the machining feed rate in the machining program according to the displacement and the dwell time. Among them, the position of the machining point is the coordinate of the machining point in the position axis coordinate system, the posture is the coordinate of the machining tool in the posture axis coordinate system, and the machining feed rate is the feed rate of the machining tool in the position axis coordinate system.

[0029] In a certain embodiment, serialize the ideal stationary points, postures, and dwell times, and obtain the machining point coordinates, displacements, and feed rates through the following loop statements: For non-standard six-axis machine tools in inclined-axis CNC machine tools, there is: ; For non-standard five-axis machine tools in inclined-axis CNC machine tools, there is: .

[0030] Among them, k represents the k-th ideal stationary point after discretization, (X, Y, Z) represents the coordinates of the machining point in the position axis coordinate system, that is, the position coordinates of the k-th ideal stationary point, and (U, W, V) or (W, V) represents the coordinates of the machining tool in the attitude axis coordinate system, that is, the attitude coordinates of the machining tool at the k-th ideal stationary point. F represents the feed rate, which is the ratio of the displacement S(k) between the k-th ideal stationary point and the (k + 1)-th ideal stationary point to the dwell time of the k-th ideal stationary point. It should be noted that since the axis directions of the tool coordinate system are the same as those of the position axis coordinate system, from the formula of the feed rate F, it can be obtained that the feed rate of the machining tool in the position axis coordinate system is actually equivalent to the feed rate of the machining tool in the tool coordinate system.

[0031] The method for generating an optical machining numerical control program for an inclined-axis numerically controlled machine tool according to the embodiment of the present invention is applicable to an inclined-axis numerically controlled machine tool, that is, all attitude axes are composed of non-standard attitude axes; it is also applicable to a partially non-standard axis system machine tool, that is, the attitude axes are composed of non-standard attitude axes and standard attitude axes. To clearly illustrate the method for generating an optical machining numerical control program for an inclined-axis numerically controlled machine tool according to the embodiment of the present invention, an embodiment of a method for generating an optical machining numerical control program for a five-axis machine tool with a partially non-standard axis system is provided. The method provided in this embodiment includes: S1: Establish a tool coordinate system of the machining tool on the inclined-axis numerically controlled machine tool according to the position axis coordinate system and the attitude rotation axis coordinate system of the inclined-axis numerically controlled machine tool.

[0032] In this embodiment, that is, establish a tool coordinate system of the machining tool on a five-axis numerically controlled machine tool with a partially non-standard axis system according to the position axis coordinate system and the attitude rotation axis coordinate system of the five-axis numerically controlled machine tool with a partially non-standard axis system.

[0033] Specifically, the attitude axes of a five-axis numerically controlled machine tool with a partially non-standard axis system are defined as BV, that is, one axis is a standard attitude axis rotating around Y, and one axis is a non-standard attitude axis V. Its attitude rotation axis coordinate system is defined as X r Y r Z r , and the relationship between the attitude rotation axis coordinate system X r Y r Z r of the five-axis numerically controlled machine tool with a partially non-standard axis system and the attitude axis coordinate system BV is as Figure 5 shown. The origin O r Y r Z r of the attitude rotation axis coordinate system X r is the origin O TCoincide, and the axis directions of the tool coordinate system X'Y'Z' are the same as those of the position axis coordinate system XYZ. The configuration of the attitude rotation axis in the five-axis CNC machine tool provided in this embodiment is as Figure 6 shown, where PoleB represents the length of the B-axis rotating rod in the five-axis CNC machine tool with a partially non-standard axis system.

[0034] S2: According to the surface shape and processing technology of the optical element to be processed, obtain the surface shape residual and removal function distribution of the optical element.

[0035] In this embodiment, the surface shape of the optical element is measured by an interferometer to obtain the surface shape residual of the optical element as shown in Figure 7 shown. The processing technology selects small grinding head polishing, and its removal function distribution is as shown in Figure 8 shown.

[0036] The surface equation of the optical element to be processed is: ; where (x, y, z) represents the surface height coordinates of the optical element.

[0037] S3: Determine the processing trajectory of the optical element, and combine the surface shape residual and removal function distribution obtained in step S2 to determine the ideal dwell point and dwell time for processing the optical element.

[0038] In this embodiment, the ideal dwell point coincides with the surface shape point. The dwell time is calculated by the following formula: ; The obtained dwell time is as shown in Figure 9 shown.

[0039] S4: According to the tool coordinate system and attitude axis coordinate system in step S1, and the surface shape, determine the attitude of the processing tool during processing.

[0040] In this embodiment, step S4 includes: Obtain the coordinate transformation operator Trans between the tool coordinate system and the attitude axis coordinate system, that is: ; where represents the composition of operations, which are executed sequentially from right to left. That is, this transformation first rotates α° around the Y r axis, then reverses the Y r axis, then reverses the X r axis, and finally obtains the spherical coordinates corresponding to the current Cartesian coordinates.

[0041] Calculate the marked point where the surface normal on the ideal tool working range of the processing tool is consistent with the surface normal of the surface shape, that is: Based on the surface equation z = f(x, y) of the optical element, the surface normal of the optical element is obtained as follows: ; wherein, represents the surface normal of the optical element. The marked point is obtained by the following formula: ; wherein, P I represents the marked point, and p represents the calculation parameter of the action point of the processing tool on the B-axis rotating rod, which is: ; The marked point is transformed into an attitude through the coordinate transformation operator, that is: .

[0042] S5: Determine the processing program for machining the optical element according to the attitude obtained in step S4 and the ideal dwell point and dwell time obtained in step S3.

[0043] In this embodiment, the ideal dwell point, attitude, and dwell time are serialized, and the position, attitude, displacement, and feed speed of the machining point are obtained through the following loop statement: .

[0044] After obtaining the position (X, Y, Z) of the machining point, the attitude (B, V) of the machining point, and the feed speed F, a partial machining program as shown in Figure 10 is obtained.

[0045] It should be understood that various forms of the flow shown above can be used, steps can be reordered, added, or deleted. For example, the steps recorded in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitations are imposed herein.

[0046] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub - combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for generating a numerical control program for optical machining of an inclined axis numerical control machine tool, characterized in that, Including: S1: Establish a tool coordinate system of the machining tool on the oblique-axis numerically controlled machine tool according to the position axis coordinate system and the attitude rotation axis coordinate system of the oblique-axis numerically controlled machine tool; S2: Obtain the surface shape residual and the removal function distribution of the optical element according to the surface shape and the machining process of the optical element to be machined; S3: Determine the machining trajectory of the optical element, and combine the surface shape residual and the removal function distribution obtained in step S2 to determine the ideal dwell point and the dwell time for machining the optical element; S4: Determine the attitude of the machining tool during machining according to the tool coordinate system in step S1, the attitude axis coordinate system of the oblique-axis numerically controlled machine tool, and the surface shape; S5: Determine the machining program for machining the optical element according to the attitude obtained in step S4, and the ideal dwell point and the dwell time obtained in step S3.

2. The optical machining numerical control program generation method for the inclined axis numerical control machine tool according to claim 1, wherein In step S1, the origin of the attitude rotation axis coordinate system coincides with the origin of the tool coordinate system, and the axis directions of the tool coordinate system are the same as those of the position axis coordinate system.

3. The optical machining numerical control program generation method for the skew axis numerically controlled machine tool according to claim 1, characterized in that, In step S3: Determine the ideal dwell point according to the machining trajectory and the surface shape; Calculate the dwell time by the following formula: ； Among them, e i = E(x i , y i , z i ), r ij = R j (x i - ε j , y i - η j , z i - γ j ), t j = T(ε j , η j , γ j ), E(x i , y i , z i ) represents the surface residual of the i-th surface point (x i , y i , z i ), where 1 ≤ i ≤ I, and I represents the total number of the surface points (x i , y i , z i ). R j (x i - ε j , y i - η j , z i - γ j ) represents the removal function distribution at the j-th ideal dwell point (ε j , η j , γ j ). T(ε j , η j , γ j ) represents the dwell time of the j-th ideal dwell point (ε j , η j , γ j ), where 1 ≤ j ≤ J, and J represents the total number of the ideal dwell points (ε j , η j , γ j ).

4. The optical machining numerical control program generation method for the inclined axis numerical control machine tool according to claim 1, wherein, In step S4: Obtain the coordinate transformation operator between the tool coordinate system and the attitude axis coordinate system; Calculate the marked points where the surface normal on the ideal tool working range of the machining tool is consistent with the surface normal of the surface shape; Convert the marked points into the attitude through the coordinate transformation operator.

5. The optical machining numerical control program generation method for the oblique-axis numerically controlled machine tool according to claim 1, wherein In step S5: The ideal dwell point is the position of the machining point in the machining program; The attitude is the attitude of the machining tool at the corresponding machining point described in the machining program during machining; Calculate the displacement between two ideal dwell points, and obtain the machining feed rate in the machining program according to the displacement and the dwell time.

6. The optical machining numerical control program generation method for the skew axis numerically controlled machine tool according to claim 5, characterized in that, The position of the machining point is the coordinate of the machining point in the position axis coordinate system, the attitude is the coordinate of the machining tool in the attitude axis coordinate system, and the machining feed rate is the feed rate of the machining tool in the position axis coordinate system.

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