Cutter path generation method, cutter path generation system and computer readable storage medium

Abstract

The cutter path generation method is used for fixed shaft milling and comprises the steps that a workpiece geometry is input, and the workpiece geometry comprises a cutting area; defining an area, which is communicated with the cutting area and located in the same height range, on the workpiece geometry as an auxiliary area, wherein the height is the height defined in the cutter shaft direction; defining a region formed by combining the cutting region and the auxiliary region as a transition region; generating a spiral cutter path of the transition area; and replacing a portion of the spiral tool path for cutting the auxiliary area with a non-cutting tool path. The cutter path generation method is beneficial to improving the uniformity of the cutter path. In addition, the invention further provides a corresponding tool path generation system and a computer readable storage medium.

Description

Technical Field

[0001] The present invention relates to a tool path generation method, in particular to a tool path generation method for fixed-axis milling, a corresponding tool path generation system and a computer-readable storage medium. Background Art

[0002] Existing tool path generation methods for fixed-axis milling, when used on workpieces whose cutting areas are partially continuous and partially discontinuous along the circumference perpendicular to the tool axis, generate spiral tool paths that are locally too dense, and the workpiece obtained after processing is prone to forming dents on the surface. Summary of the Invention

[0003] The object of the present invention is to provide a tool path generation method which is beneficial to improving the uniformity of the tool path when used for a workpiece whose cutting area is partially continuous and another partially discontinuous along the circumference perpendicular to the tool axis.

[0004] Another object of the present invention is to provide a computer-readable storage medium that is useful for improving the uniformity of a tool path when used for cutting a workpiece whose circumferential region is partially continuous and another partially discontinuous along a circumferential direction perpendicular to the tool axis.

[0005] Another object of the present invention is to provide a tool path generation system that is conducive to improving the uniformity of the tool path when used for cutting a workpiece whose cutting area is partially continuous and another partially discontinuous along the circumference perpendicular to the tool axis.

[0006] A specific embodiment of the present disclosure provides a tool path generation method for fixed axis milling, comprising:

[0007] Input the workpiece geometry, which includes the cutting area;

[0008] The area on the workpiece geometry that is connected to the cutting area and is in the same height range is defined as the auxiliary area. The height is defined along the tool axis direction.

[0009] The area formed by merging the cutting area and the auxiliary area is defined as the transition area;

[0010] Generate a spiral toolpath for the transition area; and

[0011] Replace the portion of the spiral toolpath used for cutting assist areas with a non-cutting toolpath.

[0012] The tool path generation method is beneficial to improving the uniformity of the tool path when used for a workpiece whose cutting area is partially continuous and another partially discontinuous along a circumferential direction perpendicular to the tool axis.

[0013] In another exemplary embodiment of the tool path generation method, the step of generating a spiral tool path for a transition region includes:

[0014] Generate a contour tool path in the transition area, the contour tool path includes several closed curves, and one closed curve corresponds to one cutting layer;

[0015] generating a spiral curve connecting two adjacent closed curves between each two adjacent closed curves, wherein each two adjacent spiral curves are connected to the same point of the closed curves, and each spiral curve is configured so that when the tool tip moves along the spiral curve, the tool always contacts the transition region; and

[0016] Connect the two closed curves at both ends and all the spiral curves to form a spiral tool path.

[0017] In another exemplary embodiment of the tool path generation method, the step of generating a contour tool path for a transition region includes:

[0018] Move the tool toward the transition area along the tool axis direction and stop when the tool contacts the transition area;

[0019] generating a three-dimensional mesh based on a set of coordinates of the tool tip point when the tool contacts the transition region; and

[0020] The closed curves of several cutting layers are calculated based on the 3D mesh to obtain the tool path with equal height.

[0021] In another exemplary embodiment of the tool path generation method, the step of generating a spiral curve connecting two adjacent closed curves between each two closed curves includes:

[0022] According to each discrete point of the closed curve located on the upper layer of each of the two adjacent closed curves, the corresponding point of the closed curve located on the lower layer is found along the normal direction or according to the closest distance, and each two corresponding points are connected by a line segment to form a transition line;

[0023] Select a discrete point on the uppermost closed curve as the connecting point of the spiral curve;

[0024] From top to bottom, find the discrete points of each closed curve connected to the connection point of the closed curve on the upper side through a transition line, and use them as the connection points of the spiral curve;

[0025] Projecting each transition line onto the three-dimensional grid along the tool axis direction to form a transition projection line; and

[0026] For every two adjacent closed curves, a point is taken on each transition projection line connecting the two and these points are connected by line segments to form a spiral curve.

[0027] In another exemplary embodiment of the tool path generation method, the height of each segment of the spiral curve along the tool axis is proportional to the proportion of the corresponding closed curve segment located above it in the closed curve. This can improve the uniformity of the tool path and enhance milling quality.

[0028] In another exemplary embodiment of the tool path generation method, a discrete point with the smallest curvature on the uppermost closed curve is selected as the connection point for connecting the spiral curves. This allows the tool to be inserted at a relatively flat position, which is beneficial for improving milling quality.

[0029] In another exemplary embodiment of the tool path generation method, before generating the spiral tool path in the transition region, the workpiece geometry is discretized into a triangular patch model, thereby facilitating subsequent calculations.

[0030] In another exemplary embodiment of the tool path generation method, the CAM module of Siemens NX software is used to generate the spiral tool path of the transition area, thereby improving efficiency.

[0031] Specific embodiments of the present disclosure further provide a computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program implements the steps of the tool path generation method described above. This method facilitates improving the uniformity of the tool path when used to cut a workpiece having a circumferential region that is partially continuous and partially discontinuous along a circumferential direction perpendicular to the tool axis.

[0032] Specific embodiments of the present disclosure also provide a tool path generation system for fixed-axis milling, comprising a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the tool path generation method described above. This facilitates improving the uniformity of the tool path when cutting a workpiece whose circumferential region is partially continuous and partially discontinuous along a circumferential direction perpendicular to the tool axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following drawings are only used to schematically illustrate and explain the present invention and are not intended to limit the scope of the present invention.

[0034] Figures 1 to 4 It is a flowchart for explaining an exemplary embodiment of a tool path generation method.

[0035] Figures 5 to 12 A schematic diagram for explaining an exemplary implementation of a tool path generation method.

[0036] Figure 13 A flow chart of another exemplary embodiment of a tool path generation method.

[0037] Label Description

[0038] 100 workpiece geometries

[0039] 101 cutting area

[0040] 102 auxiliary area

[0041] S tool axis direction

[0042] 10 3D grid

[0043] 20 Constant height tool paths

[0044] 21 Closed curve

[0045] 31 spiral curve

[0046] 40 spiral toolpaths

[0047] 50 non-cutting toolpaths

[0048] 61 Transition Line

[0049] 62 transition projection line DETAILED DESCRIPTION

[0050] In order to have a clearer understanding of the technical features, purposes and effects of the invention, the specific embodiments of the present invention are now described with reference to the accompanying drawings. The same reference numerals in the drawings represent components with the same structure or similar structures but the same functions.

[0051] In this document, “illustrative” means “serving as an example, instance or illustration”, and any diagram or implementation described in this document as “illustrative” should not be interpreted as a more preferred or more advantageous technical solution.

[0052] To simplify the drawings, each figure schematically shows only the parts related to the present invention, which do not represent the actual structure of the product.

[0053] Figures 1 to 4 FIG. 1 is a flow chart illustrating an exemplary embodiment of a tool path generation method for fixed axis milling. Figure 1 As shown, the tool path generation method includes the following steps S10 to S50.

[0054] S10: Input the workpiece geometry. Figure 5 As shown, the workpiece geometry 100 includes a cutting region 101 (i.e. Figure 5In this exemplary embodiment, the cutting area 101 is the area where the angle with the horizontal direction (the horizontal direction is perpendicular to the tool axis direction S) is greater than 65 degrees. The area with an angle less than 65 degrees is filled with dotted shadows and is not cut, but the present invention is not limited thereto. In other exemplary embodiments, the scope of the cutting area can be adjusted as needed. In this exemplary embodiment, the input workpiece geometry 100 is a triangular facet model. For clarity of the drawings, Figures 5 to 8 and Figures 10 to 12 The workpiece geometry 100 in FIG. 1 does not have triangular facets drawn therein, and what is shown therein is a simplified version of the triangular facet model.

[0055] S20: Define the area on the workpiece geometric body 100 that is connected to the cutting area 101 and is within the same height range as the auxiliary area 102. In this exemplary embodiment, the auxiliary area 102 is the area filled with dotted shadows. The height is defined along the tool axis direction S.

[0056] S30: The area formed by merging the cutting area 101 and the auxiliary area 102 is defined as a transition area.

[0057] S40: Generates a spiral tool path for the transition area.

[0058] Specifically, if Figure 2 As shown, step S40 includes the following steps S41 to S43, so as to improve the uniformity of the tool path.

[0059] S41: Generate a contour tool path for the transition area, where the contour tool path includes a plurality of closed curves, and one closed curve corresponds to one cutting layer.

[0060] Specifically, if Figure 3 As shown, step S41 includes the following steps S411 to S413, so as to improve the accuracy of the contour tool path.

[0061] S411: Move the tool along the tool axis direction S toward the transition area and stop when the tool contacts the transition area.

[0062] S412: Generate a set of coordinates of the tool tip point when the tool contacts the transition area Figure 6 The three-dimensional grid 10 is shown.

[0063] S413: See Figure 7 , based on the three-dimensional grid 10, the closed curves 21 of several cutting layers are calculated ( Figure 7Only one closed curve 21 is schematically shown in the figure, and a constant height tool path 20 is obtained. This step can be understood as follows: the closed curve 21 is formed by intersecting the three-dimensional grid 10 with several planes perpendicular to the tool axis direction S, and the distance between each two adjacent planes is equal.

[0064] S42: Generate a spiral curve connecting two closed curves 21 between each two adjacent closed curves 21, and each two adjacent spiral curves are connected to the same point of the closed curve 21. Each spiral curve is set so that when the tip point of the tool moves along the spiral curve, the tool is always in contact with the transition area.

[0065] Specifically: Figure 4 As shown, step S42 includes the following steps S421 to S425, so as to improve the accuracy of the spiral curve.

[0066] S421: See Figure 8 , according to each discrete point P of the closed curve 21 located on the upper layer of each of the two adjacent closed curves 21, find the corresponding point of the closed curve 21 located on the lower layer along the normal direction or according to the closest distance, and connect each two corresponding points with a line segment to form a transition line 61, Figure 8 In FIG. 6 , only a transition line 61 and two discrete points P connected thereto are schematically drawn.

[0067] S422: Select a discrete point P on the topmost closed curve 21 as a connection point for the spiral curve. In the exemplary embodiment, a discrete point P with the smallest curvature on the topmost closed curve 21 is selected as the connection point for the spiral curve. This allows the milling tool to be inserted at a relatively flat position, which improves milling quality.

[0068] S423: Find the discrete points P of each closed curve 21 connected to the connection point of the closed curve 21 located on the upper side through the transition line 61 from top to bottom, and use them as the connection points of the spiral curves.

[0069] S424: See Figure 9 , project each transition line 61 along the knife axis direction S onto the three-dimensional grid 10 to form a transition projection line 62, Figure 9 In FIG. 1 , only two transition lines 61 (drawn with dotted lines) and two transition projection lines 62 (drawn with dot-dash lines) and the discrete points P connected thereto are schematically drawn.

[0070] S425: See Figure 9 For each two adjacent closed curves 21, a point Q is taken on each transition projection line 62 connecting the two and these points are connected by line segments to form a spiral curve. The spiral curve 31 formed is as follows Figure 10 The dashed line ( Figure 10In the exemplary embodiment, each segment of the spiral curve 31 (e.g., for connecting Figure 9 The height of the line segment of the two points Q in the tool axis direction S and the corresponding closed curve 21 segment located on the upper side thereof (i.e. Figure 9 The segment between the two discrete points P on the upper middle side) occupies the closed curve 21 (i.e. Figure 9 This improves the uniformity of the tool path and helps improve milling quality.

[0071] S43: Connect the two closed curves 21 at both ends and all the spiral curves 31 to form a spiral tool path 40. The formed spiral tool path 40 is as follows: Figure 11 shown.

[0072] S50 : replacing the portion of the spiral tool path 40 used for cutting the auxiliary area 102 with the non-cutting tool path 50 . Figure 12 The state after replacement is shown in FIG, wherein the dotted part in the path is the non-cutting tool path 50, and the solid part in the path is the remaining spiral tool path 40. After the two are merged and the feed path and the retract path are added, the tool path for processing the workpiece geometry 100 is formed.

[0073] The tool path generation method is used for a workpiece (e.g. Figure 5 When machining the workpiece (as shown in the figure), it helps to improve the uniformity of the tool path.

[0074] In an exemplary embodiment, for example, the CAM module of Siemens NX software can be used to generate a spiral tool path for the transition area, thereby improving efficiency.

[0075] Figure 13 This is a flowchart of another exemplary embodiment of a tool path generation method. The tool path generation method of this exemplary embodiment differs from the previous one only in the addition of step S60. S60 specifically discretizes the workpiece geometry into a triangular facet model before generating the spiral tool path in the transition region. This facilitates subsequent calculations. In this exemplary embodiment, the input workpiece geometry is a solid model, which is converted into a triangular facet model after processing in step S60.

[0076] Specific embodiments of the present disclosure further provide a computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program implements the steps of the tool path generation method described above. This method facilitates improving the uniformity of the tool path when used to cut a workpiece having a circumferential region that is partially continuous and partially discontinuous along a circumferential direction perpendicular to the tool axis.

[0077] Specific embodiments of the present disclosure also provide a tool path generation system for fixed-axis milling, comprising a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the tool path generation method described above. This facilitates improving the uniformity of the tool path when cutting a workpiece whose circumferential region is partially continuous and partially discontinuous along a circumferential direction perpendicular to the tool axis.

[0078] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0079] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation scheme or changes that do not deviate from the technical spirit of the present invention, such as the combination, division or repetition of features, should be included in the scope of protection of the present invention.

Claims

1. A tool path generation method for fixed axis milling, characterized in that: include: Inputting a workpiece geometry, wherein the workpiece geometry includes a cutting area; An area on the workpiece geometric body that is connected to the cutting area and is within the same height range is defined as an auxiliary area, wherein the height is defined along the tool axis direction; defining an area formed by merging the cutting area and the auxiliary area as a transition area; generating a spiral tool path for the transition region; and The portion of the spiral tool path used for cutting the auxiliary area is replaced by a non-cutting tool path.

2. The tool path generation method according to claim 1, wherein: Step: Generate a spiral tool path for the transition area, including: generating a contour tool path for the transition region, wherein the contour tool path comprises a plurality of closed curves, and one closed curve corresponds to one cutting layer; generating a spiral curve connecting two adjacent closed curves between each two adjacent closed curves, wherein each two adjacent spiral curves are connected to the same point of the closed curves, and each spiral curve is configured such that when the tool tip moves along the spiral curve, the tool always contacts the transition region; and The two closed curves at both ends and all the spiral curves are connected to form the spiral tool path.

3. The tool path generation method according to claim 2, wherein: Step: Generate a contour tool path for the transition area, including: Moving the tool toward the transition area along the tool axis and stopping when the tool contacts the transition area; generating a three-dimensional grid according to a set of coordinates of a tool tip point of the tool when the tool contacts the transition region; and The closed curves of several cutting layers are calculated based on the three-dimensional grid to obtain the contour tool path.

4. The tool path generation method according to claim 3, wherein: Step: generating a spiral curve connecting two adjacent closed curves between the two closed curves, including: According to each discrete point of the closed curve located on the upper layer of each of the two adjacent closed curves, corresponding points of the closed curve located on the lower layer are found along the normal direction or according to the closest distance, and each two corresponding points are connected by a line segment to form a transition line; Selecting a discrete point on the closed curve at the top layer as a connection point for connecting the spiral curves; Finding, from top to bottom, discrete points of each closed curve connected to the connection point of the closed curve located above through the transition line, and using them as connection points for connecting the spiral curves; Projecting each of the transition lines onto the three-dimensional grid along the tool axis direction to form a transition projection line; and For each two adjacent closed curves, a point is taken on each transition projection line connecting the two closed curves and these points are connected by line segments to form the spiral curve.

5. The tool path generation method according to claim 4, wherein: The height of each segment of the spiral curve along the knife axis direction is proportional to the proportion of the corresponding segment of the closed curve located above it to the closed curve.

6. The tool path generation method according to claim 4, wherein: A discrete point with the smallest curvature is selected on the closed curve of the uppermost layer as a connection point for connecting the spiral curves.

7. The tool path generation method according to claim 1, wherein: Before generating the spiral tool path in the transition region, the workpiece geometry is discretized into a triangular patch model.

8. The tool path generation method according to claim 1, wherein: The spiral tool path for the transition area was generated using the CAM module of Siemens NX software.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the tool path generation method according to any one of claims 1 to 8 can be implemented.

10. A tool path generation system for fixed axis milling, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the tool path generation method according to any one of claims 1 to 8 can be implemented.

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