A method for recognizing a top tool model of an inserted milling based on a tool position point and a tool axis vector

Abstract

This invention provides a method for identifying a plunge milling tool model based on tool position point and tool axis vector, specifically including the following steps: S1, acquiring plunge milling tool trajectory information and initializing machined surface data; S2, recording the machined surface data formed by the previous plunge milling that meets the necessary conditions for tool interference with the current plunge milling tool position; S3, determining whether the current plunge milling tool position interferes with the machined surface data recorded in step S2; S4, recording the machined surface data of the current plunge milling tool position. The technical solution of this invention solves the problem that existing tool-workpiece meshing calculations can only determine whether plunge milling tool interference occurs when the plunge milling tool trajectory has been confirmed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machine tool control, in particular, especially relates to a kind of top cutter model identification method of plug milling based on tool position and tool axis vector establishment. BACKGROUND

[0002] Plug milling method is also called Z-axis milling method, tool makes feed movement along spindle direction, and uses the cutting edge of bottom to carry out drilling, milling combined cutting.Plug milling method has the characteristics of small radial milling force, good cutting stability, allowing to use large length-diameter ratio cutter, etc., and is very suitable for rough machining of deep cavity, deep groove type parts.Planning plug milling tool path is the premise of realizing plug milling, and the tool path planning module of three-axis plug milling at present stage is the standard configuration of mainstream CAM software.The tool path planning technology of five-axis plug milling is currently in the research and development stage, and only NREC, Hypermill and other software release some test version five-axis plug milling modules.

[0003] Plug milling top cutter is a special phenomenon in plug milling, which is usually manifested as sharp increase of cutting force at the end of tool axial feed, accompanied by loud machine vibration sound, which affects the reliability of plug milling.Currently, plug milling top cutter is judged by tool-workpiece engagement calculation method, whether the cutting area changes suddenly when the current plug milling tool feeds to the end along the axial direction is calculated, so as to judge whether there is plug milling top cutter interference.In the case that the previous plug milling tool path is determined, it is very effective to use this method to judge whether the plug milling tool position causes plug milling top cutter, but in the problem of plug milling tool path optimization, all plug milling tool positions are to be solved, and the tool-workpiece engagement calculation method cannot judge whether the cutting area changes suddenly when solving any step plug milling tool position, so it cannot provide guidance for solving plug milling tool position to avoid plug milling top cutter interference. SUMMARY

[0004] According to the above-mentioned problem that existing tool-workpiece engagement calculation can only judge whether plug milling tool causes plug milling top cutter interference in the case that plug milling tool path has been confirmed, a plug milling top cutter model identification method based on tool position and tool axis vector establishment is provided, which mainly analyzes the causes of plug milling top cutter interference from the angle of tool position and tool axis vector, and uses the top cutter model identification method of the application as a constraint condition to provide basis for top cutter-free plug milling path optimization.

[0005] The technical means adopted by the present application are as follows:

[0006] A plug milling top cutter model identification method based on tool position and tool axis vector establishment, specifically comprising the following steps:

[0007] S1, obtain plug milling tool path information, and initialize machined surface data;

[0008] S2. Record the machined surface data formed by the previous milling process that meets the necessary condition for interference with the current milling tool position;

[0009] S3. Determine whether the current position of the milling cutter interferes with the machined surface data recorded in step S2;

[0010] S4. Record the machined surface data at the current position of the milling cutter.

[0011] Further, step S1 specifically includes: extracting the tool position information of the first step of the plunge milling from the tool position list and tool axis vector list based on the acquired plunge milling tool trajectory information; discretizing the bottom circle of the tool in the first step of the plunge milling; and obtaining the discrete points [C1, C2, ..., C...]. n ] is used to initialize the processed surface data, where n represents the number of discrete points.

[0012] Furthermore, step S2 specifically includes:

[0013] Construct a cylinder based on the current position and radius of the plunge milling cutter, and project the cylinder along the current plunge milling cutter axis vector direction onto the plane containing all machined surfaces formed by previous plunge milling operations to obtain the projection curve;

[0014] If the projection curve intersects with the machined surface formed by the preceding milling, the portion IL1 of the discrete points of the projection curve located inside the machined surface and the portion IL2 of the discrete points of the machined surface located inside the projection curve are recorded in the machined surface data formed by the preceding milling that satisfies the necessary condition for top tool interference, for subsequent top tool interference judgment.

[0015] Furthermore, step S3 specifically includes:

[0016] Starting with the machined surface data recorded in step S2, and using the current tool position O of the plunger milling tool... i As the endpoint, construct a judgment vector list [V] o1 V o2, ...,V ot [This task involves determining the relationship between all vectors in the vector list and the current milling cutter axis vector V.] i The included angles [θ1,θ2,...,θ] t ], t represents the number of discrete points of the processed surface data recorded in step S2;

[0017] When [θ1,θ2,...,θ] t If a value greater than 90° exists in the value, it is considered that the current position of the milling cutter interferes with the recorded machined surface data; otherwise, it is considered that the current position of the milling cutter does not interfere with the recorded machined surface data.

[0018] Furthermore, step S4 specifically includes:

[0019] Let the discrete points of the bottom circle of the i-th step plunge milling cutter be the preliminary machined surface data of the current plunge milling cutter position. The method for updating the machined surface data of the current plunge milling cutter position based on the bottom circles of each preceding plunge milling cutter is as follows:

[0020] Project the bottom circle of the preceding milling cutter along the axis vector of the preceding milling cutter onto the plane α containing the bottom circle of the current milling cutter. i We obtain i-1 projection curves: s1, s2...S i-1 ;

[0021] Each update updates the machined surface at the current milling cutter position based on a projection curve, until all i-1 projection curves are involved in the update. Each update is based on the machined surface obtained in the previous update. The machined surface obtained in each update consists of the part of the machined surface obtained in the previous update whose projection curve is located inside the machined surface obtained in the previous update and the part of the machined surface obtained in the previous update whose projection curve is located outside the machined surface obtained in the current update.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] Existing technologies can only determine whether there is a top tool in the known plunge milling trajectory through tool-workpiece meshing calculations, but cannot provide a basis for solving plunge milling trajectories without top tool interference. This invention provides a plunge milling top tool model identification method based on the tool position point and tool axis vector in plunge milling trajectory planning. This method can be used as a constraint condition for solving the tool position point and tool axis vector, providing a basis for plunge milling tool trajectory planning without top tool interference.

[0024] Based on the above reasons, this invention can be widely applied in fields such as machine tool control. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram for initializing the processed surface data.

[0027] Figure 2 This is a schematic diagram of the machined surface data formed by a previous milling operation to record the necessary conditions for interference with the current milling cutter position.

[0028] Figure 3 This diagram illustrates how to determine if there is tool interference at the current position of the milling cutter.

[0029] Figure 4 This is a schematic diagram to record the machined surface data of the current position of the milling cutter. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figures 1-4 As shown, this invention provides a method for identifying a plunge milling cutter model based on the tool position point and tool axis vector, specifically including the following steps:

[0033] S1. Obtain the milling tool trajectory information and initialize the machined surface data;

[0034] S2. Record the machined surface data formed by the previous milling process that meets the necessary condition for interference with the current milling tool position;

[0035] S3. Determine whether the current position of the milling cutter interferes with the machined surface data recorded in step S2;

[0036] S4. Record the machined surface data at the current position of the milling cutter.

[0037] Furthermore, such as Figure 1 As shown, step S1 specifically includes: extracting the tool position information of the first step of the plunge milling from the tool position list and the tool axis vector list based on the acquired plunge milling tool trajectory information; discretizing the bottom circle of the tool in the first step of the plunge milling; and obtaining the discrete points [C1, C2, ..., C...]. n [This is used to initialize the processed surface data, where n represents the number of discrete points;]

[0038] In this embodiment, in step S1, the discrete points of the bottom circle of the tool used for the first step of the plunge milling are [C1, C2, ..., C]. 16 ].

[0039] Furthermore, such as Figure 2As shown, step S2 specifically includes:

[0040] Construct a cylinder based on the current position and radius of the plunge milling cutter, and project the cylinder along the current plunge milling cutter axis vector direction onto the plane containing all machined surfaces formed by previous plunge milling operations to obtain the projection curve;

[0041] If the projection curve intersects with the machined surface formed by the preceding milling, the portion IL1 of the discrete points of the projection curve located inside the machined surface and the portion IL2 of the discrete points of the machined surface located inside the projection curve are recorded in the machined surface data formed by the preceding milling that satisfies the necessary condition for top tool interference, for subsequent top tool interference judgment.

[0042] Furthermore, such as Figure 3 As shown, step S3 specifically includes:

[0043] Starting with the machined surface data recorded in step S2, and using the current tool position O of the plunger milling tool... i As the endpoint, construct a judgment vector list [V] o1 V o2, ...,V ot [This task involves determining the relationship between all vectors in the vector list and the current milling cutter axis vector V.] i The included angles [θ1,θ2,...,θ] t ], t represents the number of discrete points of the processed surface data recorded in step S2;

[0044] When [θ1,θ2,...,θ] t If a value greater than 90° exists in the data, it is considered that the current position of the milling cutter interferes with the recorded machined surface data; otherwise, it is considered that the current position of the milling cutter does not interfere with the recorded machined surface data.

[0045] In this embodiment, the number of discrete points of the processed surface data recorded in step S2 is 9, and the judgment vector list constructed in step S3 is [V o1 V o2, ...,V o9 Since [θ1, θ2, ..., θ9] are all less than 90°, in this embodiment, the current position of the milling cutter does not interfere with the data of the machined surface.

[0046] Furthermore, step S4 specifically includes:

[0047] Let the discrete points of the bottom circle of the plunge milling tool in the i-th step be the preliminary machined surface data of the current plunge milling tool position, such as... Figure 4 As shown in (a), the method for updating the machined surface data of the current plunger position based on the bottom circle of each preceding plunger is as follows:

[0048] Project the bottom circle of the preceding milling cutter along the axis vector of the preceding milling cutter onto the plane α containing the bottom circle of the current milling cutter. i We obtain i-1 projection curves: s1, s2...S i-1 ;

[0049] Each update updates the machined surface at the current position of the milling cutter based on a projection curve, until all i-1 projection curves are involved in the update, i.e., a total of i-1 updates are performed. Each update is based on the machined surface obtained in the previous update. The machined surface obtained in each update consists of the part of the machined surface obtained in the previous update where the projection curve used in this update is located inside the machined surface obtained in the previous update and the part of the machined surface obtained in the previous update that is located outside the projection curve used in this update.

[0050] In this embodiment, the i-2nd and i-1th update processes of the machined surface data at the current milling cutter position are shown in the figure. Figure 4 As shown in (b) and (c), the final new machined surface is as follows. Figure 4 (c) shows the shaded area.

[0051] When using the identification method provided by the present invention, after determining whether the current position of the milling cutter has been interfered with by the top tool, it is necessary to update the machined surface data through step S4. The new machined surface data obtained is a necessary condition for step S2 to be successfully performed when judging the top tool interference at the next position of the milling cutter.

[0052] The method for identifying the top milling cutter model based on the tool position point and the tool axis vector provided by this invention can be used as a constraint condition for solving the tool position point and the tool axis vector, providing a basis for planning the trajectory of the top milling cutter without top milling interference.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying a plunge milling cutter model based on the tool position point and tool axis vector, characterized in that, Specifically, the following steps are included: S1. Obtain the milling tool trajectory information and initialize the machined surface data; S2. Record the machined surface data formed by the previous milling process that meets the necessary condition for interference with the current milling tool position; S3. Determine whether the current position of the milling cutter interferes with the machined surface data recorded in step S2; S4. Record the machined surface data at the current position of the milling cutter; Step S1 specifically includes: based on the acquired plunge milling tool trajectory information, extracting the tool position information of the first plunge milling step from the tool position point list and tool axis vector list; discretizing the bottom circle of the tool in the first plunge milling step; and obtaining the discrete points [C1, C2, ..., C...]. n [This is used to initialize the processed surface data, where n represents the number of discrete points;] Step S2 specifically includes: Construct a cylinder based on the current position and radius of the plunge milling cutter, and project the cylinder along the current plunge milling cutter axis vector direction onto the plane containing all machined surfaces formed by previous plunge milling operations to obtain the projection curve; If the projection curve intersects with the machined surface formed by the previous milling, the portion IL1 of the discrete points of the projection curve located inside the machined surface and the portion IL2 of the discrete points of the machined surface located inside the projection curve are recorded in the machined surface data formed by the previous milling that satisfies the necessary condition for top tool interference, for subsequent top tool interference judgment. Step S3 specifically includes: Starting with the machined surface data recorded in step S2, and using the current tool position O of the plunger milling tool... i As the endpoint, construct a judgment vector list [V] o1 V o2, ...,V ot [This task involves determining the relationship between all vectors in the vector list and the current milling cutter axis vector V.] i The included angles [θ1,θ2,...,θ] t ], t represents the number of discrete points of the processed surface data recorded in step S2; When [θ1,θ2,...,θ] t If a value greater than 90° exists in the data, it is considered that the current position of the milling cutter interferes with the recorded machined surface data; otherwise, it is considered that the current position of the milling cutter does not interfere with the recorded machined surface data. Step S4 specifically includes: Record No. i The discrete points of the bottom circle of the step-by-step plunge milling cutter represent the preliminary machined surface data for the current plunge milling cutter position. The method for updating the machined surface data for the current plunge milling cutter position based on the bottom circles of each preceding plunge milling cutter, using this preliminary machined surface data, is as follows: Project the bottom circle of the preceding milling cutter along the axis vector of the preceding milling cutter onto the plane α containing the bottom circle of the current milling cutter. i get i- 1 Projection curves: , ... ; Each time, the machined surface at the current position of the plunger is updated based on a projection curve, until... i-1 All projection curves participate in the update; each update is based on the processed surface obtained from the previous update, and the processed surface obtained from each update consists of the part of the processed surface obtained from the previous update whose projection curve is located inside the processed surface obtained from the previous update and the part of the processed surface obtained from the previous update whose projection curve is located outside the processed surface obtained from the previous update.

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