Electrical discharge wire-cutting method based on simulation of workpiece and its trajectory by three-dimensional model

Abstract

The application relates to the field of three-dimensional processing and display technology, in particular to a wire-cut electric spark method based on three-dimensional model simulation workpieces and trajectories, which comprises the following steps: (1) collecting two-dimensional graphic data of upper and lower surfaces of a workpiece, workpiece height, workpiece-to-transmission structure height and other parameters, and inputting the parameters into a three-dimensional algorithm model; (2) the three-dimensional algorithm model proportionally divides the two-dimensional graphic data of the upper and lower surfaces of the workpiece according to a precision value, so as to obtain an equal number of upper and lower surface trajectory subdivision points; (3) the three-dimensional algorithm model alternately traverses the upper and lower surface trajectory subdivision points to form triangles and rendering; and (4) displaying a three-dimensional model of the workpiece in a software system. The three-dimensional display workpiece model greatly facilitates customers to compare software data with actual workpieces; can intuitively show real-time positions of molybdenum wires on workpiece curved surfaces, so as to facilitate inspection of a machining state; can also intuitively show real-time positions and deflection states of molybdenum wire transmission structures, so as to facilitate comparison and inspection of real-time states of the transmission structures.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional machining and display technology, and in particular to a wire feeding method in electrical discharge machining based on a three-dimensional model to simulate the workpiece and its trajectory. Background Technology

[0002] The wire feeding system in electrical discharge machining (EDM) is a proprietary control system used in metal mold processing. It consists of host computer software and a slave controller (Programmable Logic Controller (PLC) or control card, etc.). This system controls the movement of a molybdenum wire (guided through the workpiece by a guide nozzle or guide wheel) along the mold's graphic trajectory to process the mold workpiece. Depending on whether the molybdenum wire remains vertical throughout the processing, the processed workpiece can be categorized into vertical workpieces (both sides are vertical) and tapered workpieces (sides are not vertical and have an angle).

[0003] Existing wire EDM systems often use two-dimensional top views or two-dimensional simulations to display and simulate vertical and tapered workpieces. The workpiece sides are typically represented by multiple fixed-interval straight lines, which lack clarity and intuitiveness in representing the workpiece's three-dimensional structure and fail to adequately depict the curved surfaces and the details of their connections. This prevents system users from visually observing the workpiece model before machining.

[0004] Furthermore, existing wire feeding systems in electrical discharge machining (EDM) often simulate the trajectory by plotting the real-time cutting points on the upper and lower surfaces of the workpiece in a two-dimensional top view, or by connecting the real-time cutting points on the upper and lower surfaces to represent the real-time position of the molybdenum wire on the workpiece, and then displaying it in a two-dimensional simulation. This method cannot visually represent the accurate position of the molybdenum wire on the curved side surface of the workpiece, nor can it show the real-time position and deflection state of the nozzle or guide wheel, making it inconvenient for users to observe and simulate the position and state of the nozzle or guide wheel throughout the entire machining process.

[0005] Therefore, a new technical solution is urgently needed to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of the prior art and provide a wire feeding method in electrical discharge machining based on a three-dimensional model to simulate the workpiece and its trajectory, so as to solve the technical problems of the prior art.

[0007] The above objectives are achieved through the following technical solutions:

[0008] A method for wire feeding in electrical discharge machining based on 3D model simulation of the workpiece and its trajectory includes:

[0009] Step (1) Collect two-dimensional graphic data of the upper and lower surfaces of the workpiece, the workpiece height, and the height parameters of the workpiece to the transmission structure, and input them into the three-dimensional algorithm model;

[0010] In step (2), the three-dimensional algorithm model divides the two-dimensional graphic data of the workpiece on the upper and lower surfaces equally according to the accuracy value to obtain an equal number of upper and lower surface trajectory subdivision points;

[0011] In step (3), the three-dimensional algorithm model iterates through the upper and lower trajectory subdivision points in turn to form triangles and renders them;

[0012] Step (4) Display the three-dimensional model of the workpiece in the software system;

[0013] Step (5) The software system acquires the mechanical coordinates, workpiece height, and workpiece-to-transmission structure height parameters in real time;

[0014] Step (6) transform the three-dimensional spatial relationship into a two-dimensional relationship in the XOY plane and perpendicular to the XOY plane according to the workpiece cone mapping algorithm;

[0015] Step (7) Utilize the similarity between the triangles formed by the key points to back-calculate the real-time position of the cutting point of the molybdenum wire on the upper and lower surfaces of the workpiece, and input it into the three-dimensional algorithm model.

[0016] The three-dimensional algorithm model described in step (8) subdivides the two-dimensional graphic proportionally based on the real-time cutting point coordinates;

[0017] Step (9) The 3D algorithm model iterates through the triangles formed by the subdivision points in turn and renders them;

[0018] Step (10) The software system displays the real-time processing status.

[0019] Furthermore, step (2) specifically includes:

[0020] Let Lu be the length of the upper surface trajectory of the workpiece, Lb be the length of the lower surface of the workpiece, and D be the subdivision accuracy. With the lower surface of the workpiece as the reference, the subdivision accuracy of the upper surface is Du = D * (Lu / Lb).

[0021] Furthermore, step (6) specifically includes:

[0022] Let the workpiece be a truncated cone with height h, the distance from the lower surface of the truncated cone to the lower table of the machine tool be hd, and the distance from the upper surface of the truncated cone to the upper table of the machine tool be hu. The molybdenum wire intersects the upper and lower surfaces of the truncated cone at points A and B, respectively. Let the coordinates be (xa, ya) and (xb, yb), respectively. Then the real-time positions of the upper and lower transmission structures (Ou, Od) can be obtained by converting three-dimensional space to two-dimensional plane and using the triangular similarity method.

[0023] The length of AB in space is:

[0024] Where AF = h, F is the projection of A onto the plane XOY; BF = A1B1, that is...

[0025] In the plane containing the molybdenum wire and the transmission structure, the spatial lengths of UA and BD can be obtained through triangles AFB, UJA, and BKD:

[0026] UA = UJ * AB / AF

[0027] BD = BK * AB / AF

[0028] Right now:

[0029] UA=hu*AB / h

[0030] BD = hd * AB / h;

[0031] In triangles UJA and BKD, the lengths of JA and KD can be found using the Pythagorean theorem.

[0032] The coordinates of point D are obtained using trigonometric functions: D(xd,yd), where xd=xb+KD*cosβ, yd=yb-KD*sinβ (β=∠A1B1C1); the coordinates of point U are obtained similarly.

[0033] but:

[0034] Ou(xou,you)=(xu-r,yu)

[0035] Od(xod,yod)=(xd-r,yu)

[0036] Where r is the radius of the transmission structure.

[0037] Furthermore, the three-dimensional algorithm model includes OSG, OpenGL, and Easy3D.

[0038] This invention provides a method for wire feeding in electrical discharge machining (EDM) based on a 3D model simulating the workpiece and its trajectory. It employs a 3D display model of the workpiece, greatly facilitating comparison between software data and the actual workpiece. It can intuitively show the real-time position of the molybdenum wire on the workpiece's curved surface, making it easy to check the machining status. It can also intuitively show the real-time position and deflection state of the molybdenum wire transmission structure, facilitating comparison and inspection of the transmission structure's real-time status. Compared with existing technologies, this solution has the following three advantages:

[0039] 1. Existing systems often use two-dimensional top views or two-dimensional lines with fixed intervals to simulate the three-dimensional model of a workpiece, which cannot effectively represent the surface information of the workpiece's sides or the details of the connections between surfaces. This solution, however, uses a three-dimensional display to completely represent the workpiece's three-dimensional model, accurately drawing the details of the workpiece's sides. This allows customers to accurately compare the software data with the actual workpiece to identify any discrepancies, reducing processing problems caused by software calculation errors.

[0040] 2. Existing systems often use two-dimensional, fixed-interval straight lines to simulate and display the three-dimensional model of a workpiece when representing its side surface information. This fails to accurately represent the position of the molybdenum wire on the workpiece side surface during processing. This solution, however, uses a three-dimensional display to accurately depict the details of the workpiece side surface model. During processing or simulated processing, it can accurately represent the real-time position of the molybdenum wire on the workpiece side surface, as well as its location at the connection point. This facilitates customer checks on the position of the molybdenum wire during processing, allowing for the determination of any abnormalities in the current processing status.

[0041] 3. Existing systems only display the real-time position of the molybdenum wire during processing, failing to show the position and deflection state of the molybdenum wire transmission structure during processing or simulation. This prevents customers from comparing the theoretical and actual states of the transmission structure during processing or simulation debugging to identify any discrepancies. This solution utilizes a 3D display to show the real-time position and deflection state of the molybdenum wire transmission structure during processing, providing customers with a visually intuitive method to check the structural condition. Attached Figure Description

[0042] Figure 1 This is a flowchart illustrating the display of the 3D model of the workpiece in the electrical discharge machining (EDM) wire feeding method based on a 3D model to simulate the workpiece and its trajectory, as described in this invention.

[0043] Figure 2 This is a flowchart illustrating the real-time simulation of the position and state of the molybdenum wire and its transmission structure during workpiece machining in an electrical discharge machining method based on a three-dimensional model simulation of the workpiece and its trajectory, as described in this invention.

[0044] Figure 3 This is a schematic diagram of the cone mapping application in electrical discharge machining based on a three-dimensional model to simulate the workpiece and its trajectory, as described in this invention. (3a) is a three-dimensional schematic diagram of a frustum, (3a) is a front view of the frustum, (3a) is a top view of the frustum, and (3a) is a side view of the frustum. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. The described embodiments are merely some, not all, of the embodiments of the present invention. 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.

[0046] like Figure 1 and 2 As shown, an electrical discharge machining (EDM) wire feeding method based on a three-dimensional model to simulate the workpiece and its trajectory is presented. The three-dimensional display algorithm is used to intuitively represent the three-dimensional model of the entire workpiece and to display the real-time position and deflection state of the molybdenum wire and its transmission structure (guide nozzle, guide wheel) during the machining or simulation process. This allows users to intuitively grasp the workpiece shape and real-time machining status calculated by the software and to promptly identify problems.

[0047] The main features of this method are as follows: In order to accurately draw the workpiece model and the real-time machining position status, it is necessary to input the two-dimensional graphic data of the upper and lower surfaces of the workpiece, the workpiece height, the height between the workpiece and the transmission structure, and other parameters into the three-dimensional model algorithm to draw the three-dimensional view of the workpiece; during the machining process, the host computer software extracts the mechanical coordinate position of the current molybdenum wire transmission structure in real time, and calculates the real-time position of the cutting point of the molybdenum wire on the upper and lower surfaces of the workpiece through the cone mapping algorithm. The three-dimensional model algorithm displays the position of the molybdenum wire, the real-time position of the molybdenum wire transmission structure, and the deflection state on the workpiece in real time.

[0048] The specific steps include:

[0049] Step (1) Collect two-dimensional graphic data of the upper and lower surfaces of the workpiece, the workpiece height, and the height parameters of the workpiece to the transmission structure, and input them into the three-dimensional algorithm model;

[0050] Specifically, the two-dimensional graphic data of the upper and lower surfaces of the workpiece, the workpiece height, the distance between the upper surface of the workpiece and the upper transmission structure, and the distance between the lower surface of the workpiece and the lower transmission structure are input into the three-dimensional algorithm model. In this embodiment, the three-dimensional algorithm model includes commonly used three-dimensional tools such as OSG, OpenGL, and Easy3D.

[0051] In step (2), the three-dimensional algorithm model divides the two-dimensional graphic data of the workpiece on the upper and lower surfaces equally according to the accuracy value to obtain an equal number of upper and lower surface trajectory subdivision points;

[0052] Specifically, the two-dimensional graphic paths on the upper and lower surfaces are subdivided into curves evenly according to the accuracy value. To ensure the synchronization of the upper and lower trajectories and to make the paths on the upper and lower surfaces have the same number of subdivision points, the angle and length values ​​used when subdividing the curves need to be adjusted according to the length ratio of the upper and lower trajectories, so as to ensure that the drawn surface is relatively uniform.

[0053] In step (3), the three-dimensional algorithm model iterates through the upper and lower trajectory subdivision points in turn to form triangles and renders them;

[0054] Step (4) Display the three-dimensional model of the workpiece in the software system;

[0055] The steps (3) to (4) are as follows: set Lu as the length of the upper surface trajectory, Lb as the length of the lower surface, and D as the subdivision precision. With the lower surface as the reference, the subdivision precision of the upper surface is Du = D * (Lu / Lb). Then, by traversing the subdivision points on the upper and lower trajectories in turn, triangles are formed and rendered to form the cut three-dimensional model.

[0056] Step (5) The software system acquires the mechanical coordinates, workpiece height, and workpiece to transmission structure height parameters in real time; during the machining or simulated machining process, the host computer software of the wire feeding system in the EDM process acquires the real-time mechanical position of the molybdenum wire transmission structure, i.e., the mechanical coordinates, from the lower computer controller in real time;

[0057] Step (6) transform the three-dimensional spatial relationship into a two-dimensional relationship in the XOY plane and perpendicular to the XOY plane according to the workpiece cone mapping algorithm;

[0058] Step (7) Utilize the similarity between the triangles formed by the key points to back-calculate the real-time position of the cutting point of the molybdenum wire on the upper and lower surfaces of the workpiece, and input it into the three-dimensional algorithm model.

[0059] Specifically, the key points are the similarity between the upper and lower shaft positions and the triangles formed by the intersection of the molybdenum wire and the upper and lower planes of the workpiece. The real-time position of the cutting point of the molybdenum wire on the upper and lower surfaces of the workpiece is calculated in reverse and fed into the three-dimensional model algorithm to draw the real-time position of the molybdenum wire, the real-time position of its transmission structure, and the deflection state.

[0060] The three-dimensional algorithm model described in step (8) subdivides the two-dimensional graphic proportionally based on the real-time cutting point coordinates;

[0061] Step (9) The 3D algorithm model iterates through the triangles formed by the subdivision points in turn and renders them;

[0062] Step (10) The software system displays the real-time processing status.

[0063] In 3D trajectory surface simulation, the path is divided into two trajectory curves, one processed and one unprocessed, based on the real-time mechanical position. Then, using discrete curves and rendering methods similar to the above algorithm, a surface is drawn that is bounded by the lines connecting the two processed trajectories and the two processing position points, thus forming the processing trajectory surface.

[0064] The cone mapping algorithm in step (6) transforms the three-dimensional spatial relationship into a two-dimensional planar relationship for calculation, specifically as follows:

[0065] like Figure 3 As shown, a truncated cone is on a machine tool. The workpiece is defined as a truncated cone with height h. The distance from the lower surface of the truncated cone (XY motor shaft plane) to the lower table of the machine tool is hd, and the distance from the upper surface of the truncated cone to the upper table of the machine tool is hu. The molybdenum wire intersects the upper and lower surfaces of the truncated cone at points A and B, respectively. Let their coordinates be (xa, ya) and (xb, yb), then the real-time positions of the upper and lower transmission structures (Ou, Od) can be determined by converting three-dimensional space to a two-dimensional plane and using trigonometric similarity methods.

[0066] As shown in Figure (3a), the length of AB in space is:

[0067] Where AF = h, F is the projection of A onto the plane XOY; as shown in Figure (3c), BF = A1B1, that is

[0068] In the plane containing the molybdenum wire and the transmission structure (which is perpendicular to the plane YOZ), the spatial lengths of UA and BD can be obtained through triangles AFB, UJA, and BKD (as shown in Figure (3a), where J is the projection of U onto the plane of the cone frustum and K is the projection of B onto the lower plane of the machine tool).

[0069] UA = UJ * AB / AF

[0070] BD = BK * AB / AF

[0071] Right now:

[0072] UA=hu*AB / h

[0073] BD = hd * AB / h;

[0074] In triangles UJA and BKD, the lengths of JA and KD can be found using the Pythagorean theorem.

[0075] The coordinates of point D are obtained by trigonometric functions: D(xd,yd), where xd=xb+KD*cosβ, yd=yb-KD*sinβ (β=∠A1B1C1, as shown in Figure (3c)); the coordinates of point U are obtained similarly.

[0076] but:

[0077] Ou(xou,you)=(xu-r,yu)

[0078] Od(xod,yod)=(xd-r,yu)

[0079] Where r is the radius of the transmission structure.

[0080] The above description is merely illustrative of the embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for wire feeding in electrical discharge machining based on 3D model simulation of the workpiece and its trajectory, characterized in that, include: Step (1) Collect two-dimensional graphic data of the upper and lower surfaces of the workpiece, the workpiece height, and the height parameters of the workpiece to the transmission structure, and input them into the three-dimensional algorithm model; In step (2), the three-dimensional algorithm model divides the two-dimensional graphic data of the workpiece on the upper and lower surfaces equally according to the accuracy value to obtain an equal number of upper and lower surface trajectory subdivision points; In step (3), the three-dimensional algorithm model iterates through the upper and lower trajectory subdivision points in turn to form triangles and renders them; Step (4) Display the three-dimensional model of the workpiece in the software system; Step (5) The software system acquires the mechanical coordinates, workpiece height, and workpiece-to-transmission structure height parameters in real time; Step (6) transform the three-dimensional spatial relationship into a two-dimensional relationship in the XOY plane and perpendicular to the XOY plane according to the workpiece cone mapping algorithm; Step (7) Utilize the similarity between the triangles formed by the key points to back-calculate the real-time position of the cutting point of the molybdenum wire on the upper and lower surfaces of the workpiece, and input it into the three-dimensional algorithm model. The three-dimensional algorithm model described in step (8) subdivides the two-dimensional graphic proportionally based on the real-time cutting point coordinates; Step (9) The 3D algorithm model iterates through the triangles formed by the subdivision points in turn and renders them; Step (10) The software system displays the real-time processing status.

2. The method for wire feeding in electrical discharge machining based on a three-dimensional model simulating the workpiece and its trajectory, as described in claim 1, is characterized in that... Step (2) specifically involves: Let Lu be the length of the upper surface trajectory of the workpiece, Lb be the length of the lower surface of the workpiece, and D be the subdivision accuracy. With the lower surface of the workpiece as the reference, the subdivision accuracy of the upper surface is Du = D * (Lu / Lb).

3. The method for wire feeding in electrical discharge machining based on a three-dimensional model simulating the workpiece and its trajectory, as described in claim 2, is characterized in that... Step (6) specifically involves: Let the workpiece be a truncated cone with a height of h, the distance from the lower surface of the truncated cone to the lower table of the machine tool be hd, and the distance from the upper surface of the truncated cone to the upper table of the machine tool be hu. The molybdenum wire intersects the upper and lower surfaces of the truncated cone at points A and B, respectively. Let the coordinates be (xa, ya) and (xb, yb), respectively. Then the real-time positions of the upper and lower transmission structures (Ou, Od) can be obtained by converting three-dimensional space to two-dimensional plane and using the triangular similarity method. The length of AB in space is: Where AF = h, F is the projection of A onto the plane XOY; BF = A1B1, that is... In the plane containing the molybdenum wire and the transmission structure, the spatial lengths of UA and BD can be obtained through triangles AFB, UJA, and BKD: UA = UJ * AB / AF BD = BK * AB / AF Right now: UA=hu*AB / h BD = hd * AB / h; In triangles UJA and BKD, the lengths of JA and KD can be found using the Pythagorean theorem. The coordinates of point D are obtained using trigonometric functions: D(xd,yd), where xd=xb+KD*cosβ, yd=yb-KD*sinβ (β=∠A1B1C1); the coordinates of point U are obtained similarly. but: Ou(xou,you)=(xu-r,yu) Od(xod,yod)=(xd-r,yu) Where r is the radius of the transmission structure.

4. The method for wire feeding in electrical discharge machining based on a three-dimensional model simulating the workpiece and its trajectory, as described in claim 1, is characterized in that... The three-dimensional algorithm models include OSG, OpenGL, and Easy3D.

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