A method for generating a tool path for machining a bottom surface of a die holder

Abstract

This invention discloses a method for generating toolpaths for machining the bottom plane of a mold base. First, a backup file containing only point hole toolpaths is created. Then, the mold base model is imported, and the bottom surface range is identified. Next, point hole toolpaths are arrayed across the entire bottom surface range. Through toolpath overcutting checks, point hole toolpaths falling on the ribs and base plate are retained. The original points of these point hole toolpaths are saved to a point set. Squares with a side length equal to the tool cutting width are evenly distributed across the entire bottom surface range. The relationship between the squares and the point set is compared, and squares without any points are removed. Squares with only two rows or two columns at the ribs are merged into one row or one column. The center points of the squares are connected in batches to form multiple straight lines parallel to the X-axis or Y-axis. After ensuring that all square center points are connected, the connected straight lines are converted into toolpaths. The toolpaths are sorted according to the minimum connection distance using software sorting functions, and then converted into reference lines. Adjacent reference lines are connected end-to-end to finally form a continuous reference line.

Description

Technical Field

[0001] This invention relates to the field of mold cutting and machining technology, and specifically to a method for generating toolpaths for machining the bottom plane of a mold base. Background Technology

[0002] As the supporting structure of a mold, the mold base bears the weight and working load of the mold, ensuring its stable operation. It is an indispensable part in the mold manufacturing process. However, since the mold base itself is also a casting, its bottom surface needs to be machined by a CNC milling machine before it can be used in parts manufacturing.

[0003] In existing technologies, the machining of the bottom plane of a mold base generally employs two methods: parallel machining or machining around the boundary. Parallel machining is undoubtedly the most efficient method for planar machining because the toolpath is straight, ensuring a high cutting speed without deceleration. However, for some mold base bottom surfaces with large cavities, the idle travel may exceed 50%, resulting in a significant amount of ineffective cutting. While machining around the boundary avoids cavities, the toolpath in this method constantly changes direction, leading to severe deceleration and difficulty in improving efficiency. Furthermore, this method involves the toolpath traversing all ribs twice, meaning that approximately half of the toolpath for ribs is also idle travel, further reducing machining efficiency.

[0004] In addition to the two machining methods mentioned above, in practical applications, the bottom boundary of the mold base is also combined with parallel machining. However, for the bottom plane of the mold base with many holes, the machining toolpath is very fragmented with many short toolpaths, which also makes it impossible to maintain a high cutting speed.

[0005] For machining the bottom plane of the mold base, the most effective toolpath is to take a long straight line as much as possible and ensure that it only goes once on the rib to minimize idle travel. Although this kind of toolpath can be generated by manually drawing reference lines in CNC machining software, manually drawing reference lines is very difficult and time-consuming. Summary of the Invention

[0006] In view of this, the present invention provides a method for generating toolpaths for machining the bottom plane of a mold base, which aims to automatically generate the optimal toolpath for machining the bottom plane of the mold base and ensure the machining efficiency of the bottom plane of the mold base.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A method for generating toolpaths for machining the bottom plane of a mold base, characterized by comprising the following steps:

[0009] Step 1: Create a project file containing only the toolpath for the point holes in the CNC machining software for later use;

[0010] Step 2: Import the mold base model to be processed into the CNC machining software and obtain the bottom surface range of the mold base model to be processed;

[0011] Step 3: Import the project file described in Step 1, and align one corner of the hole toolpath with one corner of the bottom surface of the mold base to be processed through transformation operations;

[0012] Step 4: Calculate how many hole toolpaths are needed in the X-axis and Y-axis directions within the bottom surface area described in Step 2 to cover the entire bottom surface of the mold base;

[0013] Step 5: Based on the data calculated in Step 4, copy and translate the point hole toolpath to completely cover the bottom surface of the mold base;

[0014] Step 6: Eliminate the toolpaths of the point holes in the cavity, and save the coordinates of the remaining point hole toolpaths to a new point set;

[0015] Step 7: Construct a square with the cutting width of the tool as its side length, and introduce i and j to number it;

[0016] Step 8: Distribute the squares established in Step 7 evenly across the entire bottom surface of the mold base, and compare the relationship between the squares and the point set described in Step 6. Remove the squares that do not contain any points.

[0017] Step 9: Merge squares that have only two adjacent frames in the X-axis and Y-axis directions;

[0018] Step 10: Obtain the center point of all squares, and connect the center points of the squares in sequence. Connect more than N points that are located on the same straight line and parallel to the X-axis or Y-axis to form a reference line parallel to the X-axis or Y-axis.

[0019] Step 11: Change the critical value to N-5, and connect the remaining points with straight lines again;

[0020] Step 12: Change the critical value to N-7, and connect the remaining points after step 11 with a straight line again;

[0021] Step 13: Check if there are any remaining points, and connect the remaining points to the nearest straight line;

[0022] Step Fourteen: Convert the reference lines obtained in Steps Ten to Thirteen into toolpaths, and sort the toolpaths according to the minimum connection distance;

[0023] Step 15: Convert the sorted toolpaths into reference lines, and connect the start and end points of adjacent reference lines to form a continuous reference line.

[0024] Using the above method, an optimal machining toolpath can be generated quickly, thereby ensuring machining efficiency.

[0025] As a preferred embodiment: the point hole toolpath described in step one contains 10,000 points, arrayed on coordinate axes with an array distance of 10, and covering a range of 990*990.

[0026] Preferably, the CNC machining software is NX or PowerMill.

[0027] Preferably, in step three, the lower left corner of the hole toolpath is aligned with the lower left corner of the bottom surface of the mold base to be processed by translation and selection.

[0028] As a preferred option, step six utilizes the toolpath overcutting check in CNC machining software to eliminate toolpaths for point holes within cavities.

[0029] Preferably, N is 10 in step ten.

[0030] As a preferred embodiment, step fourteen uses the sorting function provided by the CNC machining software to sort the toolpaths according to the minimum connection distance.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] The toolpath generation method for machining the bottom plane of a mold base provided by this invention can automatically generate multiple straight lines on the mold base plate and ribs. Then, the toolpaths are sorted according to the minimum connection distance using the sorting function of CNC machining software. Finally, the straight lines are connected in sequence to form a continuous reference line. This route is mostly straight, and there are no continuous corners that would cause the tool to decelerate. At the same time, it effectively avoids ineffective machining in cavities, greatly improving the machining efficiency of mold base machining. Attached Figure Description

[0033] Figure 1 A three-dimensional structural diagram to show the optimal toolpath for machining the bottom surface of the mold base;

[0034] Figure 2 To illustrate the structural diagram after the toolpath cutting inspection;

[0035] Figure 3 for Figure 2 A magnified view of a portion of the image;

[0036] Figure 4 To illustrate the structure after removing the squares that do not contain any points;

[0037] Figure 5 To illustrate the structure with only two rows of squares at the ribs;

[0038] Figure 6 for Figure 5 A schematic diagram of the structure after being merged into a row of squares;

[0039] Figure 7 To illustrate the structure with only two rows of squares at the ribs;

[0040] Figure 8 for Figure 7 A schematic diagram of the structure after being merged into a row of squares;

[0041] Figure 9 To illustrate the structure after all squares are connected;

[0042] Figure 10 A schematic diagram illustrating the optimal toolpath. Detailed Implementation

[0043] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0044] A method for generating toolpaths for machining the bottom plane of a mold base includes the following steps:

[0045] Step 1: First, create a spare project file in the CNC machining software. Delete all models, features, and other irrelevant content from the project file, keeping only the point hole toolpath. In this embodiment, NX or PowerMill is used as the CNC machining software. The point hole toolpath contains 10,000 points arrayed along coordinate axes with a spacing of 10, covering a range of 990*990. This ensures more complete coverage of the mold base bottom surface and guarantees machining accuracy.

[0046] Step 2: Import the mold base model A to be machined into the CNC machining software and obtain the bottom surface range of the mold base model A. The specific code is as follows:

[0047] Dim xmin,xmax,ymin,ymax,zmin,zmax As Double

[0048] PMILL.GetEntitySize(enumPowerMILLEntityType.pmPattern,pattern,xmin,xmax,ymin,ymax,zmin,zmax)

[0049] PMILL.Execute("DELETE PATTERN;")

[0050] xmin = Round(xmin, 3)

[0051] xmax = Round(xmax, 3)

[0052] ymin = Round(ymin, 3)

[0053] ymax = Round(ymax, 3)

[0054] zmin = Round(zmin, 3)

[0055] zmax = Round(zmax, 3).

[0056] Step 3: Import the project file created in Step 1. Align the lower left corner of the hole toolpath with the lower left corner of the bottom surface of the mold base A to be processed by translation and rotation. The specific code is as follows:

[0057]

[0058]

[0059] Step 4: Calculate how many hole toolpaths are needed in the X-axis and Y-axis directions to completely cover the bottom surface of the mold base A obtained in Step 2. The specific code is as follows:

[0060]

[0061]

[0062] Step 5: Based on the results calculated in Step 4, the bottom surface of the mold base A to be machined is completely covered by copying and shifting the toolpath of the point holes. The specific code is as follows:

[0063]

[0064] Step Six: Use the toolpath overcut check function in the CNC machining software to eliminate the toolpaths for the point holes in cavity 1, retaining only the toolpaths for the point holes falling on the mold base plate 2 and the rib 3. See [link / reference] for the specific effect. Figure 2 and Figure 3 The coordinates of the toolpaths for the holes falling on the base plate 2 and the rib 3 are saved to a new point set. The specific code is as follows:

[0065]

[0066] Step 7: Create a square 'a' with the cutting width of the tool as its side length, and introduce 'i' and 'j' into the square structure to number it, which facilitates the expression of the relative position of the remaining square 'a' on the plane. The specific code is as follows:

[0067]

[0068]

[0069] Step 8: As Figure 4As shown, squares a established in step seven are evenly distributed across the entire bottom surface of the mold base A to be processed. The relationship between square a and the point set stored in step six is ​​compared, and squares a that do not contain any points are removed. The specific code is as follows:

[0070]

[0071]

[0072] Step Nine: Figures 5 to 8 As shown, squares 'a' with only two adjacent boxes in the X and Y directions are merged into a row or column. The code for merging in the X-axis direction is as follows:

[0073]

[0074]

[0075] Since the code for merging the Y-axis direction is similar, it will not be shown again here.

[0076] Step 10: Obtain the center points of all squares a, and connect the center points of squares a sequentially. Connect points that are more than N points on the same straight line and parallel to the X-axis or Y-axis to form a reference line 4 parallel to the X-axis or Y-axis. In this embodiment, N is a natural number, and N is preferably 10 as the critical point. The code for generating the reference line parallel to the X-axis is as follows:

[0077]

[0078]

[0079] The code for generating a reference line parallel to the Y-axis is similar and will not be shown again here.

[0080] Step 11: Change the threshold to 5 and connect the remaining points with straight lines again.

[0081] Step 12: Change the threshold to 3 again, and connect the remaining points after step 11 with a straight line.

[0082] Step 13: Check if there are any remaining points. If so, connect the remaining points to the nearest straight line to obtain the final result as shown below. Figure 9 The resulting effect is shown in the following code:

[0083]

[0084]

[0085] Step Fourteen: Convert the reference line 4 obtained in Steps Ten to Thirteen into toolpaths, and use the sorting function provided by the CNC machining software to sort the toolpaths according to the minimum connection distance.

[0086] Step 15: Convert the sorted toolpaths into reference lines 4, and connect the start and end points of adjacent reference lines to form a continuous reference line 5, as shown in the following steps. Figure 10 As shown.

[0087] With this invention, by simply importing the mold base, multiple straight lines can be automatically generated on the base plate 2 and ribs 3 of the mold base. Then, the sorting function of the CNC machining software is used to sort the toolpaths according to the minimum connection distance. Finally, all the straight lines are connected in sequence to form the optimal toolpath. This path is mostly straight, and there will be no problem of tool deceleration due to continuous corners. At the same time, it also effectively avoids invalid machining at the cavity 1, which greatly improves the machining efficiency.

[0088] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A method for generating toolpaths for machining the bottom plane of a mold base, characterized in that, Includes the following steps: Step 1: Create a project file containing only the toolpath for the point holes in the CNC machining software for later use; Step 2: Import the mold base model to be processed into the CNC machining software and obtain the bottom surface range of the mold base model to be processed; Step 3: Import the project file described in Step 1, and align one corner of the hole toolpath with one corner of the bottom surface of the mold base to be processed through transformation operations; Step 4: Calculate how many hole toolpaths are needed in the X-axis and Y-axis directions within the bottom surface area described in Step 2 to cover the entire bottom surface of the mold base; Step 5: Based on the data calculated in Step 4, copy and translate the point hole toolpath to completely cover the bottom surface of the mold base; Step 6: Eliminate the toolpaths of the point holes in the cavity, and save the coordinates of the remaining point hole toolpaths to a new point set; Step 7: Construct a square with the cutting width of the tool as its side length, and introduce i and j to number it; Step 8: Distribute the squares established in Step 7 evenly across the entire bottom surface of the mold base, and compare the relationship between the squares and the point set described in Step 6. Remove the squares that do not contain any points. Step 9: Merge squares that have only two adjacent frames in the X-axis and Y-axis directions; Step 10: Obtain the center point of all squares, and connect the center points of the squares in sequence. Connect more than N points that are located on the same straight line and parallel to the X-axis or Y-axis to form a reference line parallel to the X-axis or Y-axis. Step 11: Change the critical value to N-5, and connect the remaining points with straight lines again; Step 12: Change the critical value to N-7, and connect the remaining points after step 11 with a straight line again; Step 13: Check if there are any remaining points, and connect the remaining points to the nearest straight line; Step Fourteen: Convert the reference lines obtained in Steps Ten to Thirteen into toolpaths, and sort the toolpaths according to the minimum connection distance; Step 15: Convert the sorted toolpaths into reference lines, and connect the start and end points of adjacent reference lines to form a continuous reference line.

2. The method of claim 1, wherein: The point hole toolpath described in step one contains 10,000 points, arrayed on coordinate axes with an array distance of 10, covering a range of 990*990.

3. The method of claim 1, wherein: The CNC machining software is NX or PowerMill.

4. The method of claim 1, wherein: In step three, the lower left corner of the hole toolpath is aligned with the lower left corner of the bottom surface of the mold base to be processed by translation and selection.

5. The method of claim 1, wherein: Step six utilizes the toolpath overcutting check function in the CNC machining software to eliminate toolpaths for point holes within the cavity.

6. The method of claim 1, wherein: In step ten, N is 10.

7. The method of claim 1, wherein: Step fourteen uses the sorting function provided by the CNC machining software to sort the toolpaths according to the minimum connection distance.

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