A tool body definition method based on feature recognition

Abstract

The present invention proposes a tool body definition method based on feature recognition, comprising the following steps: inputting a sheet metal model; obtaining the current sheet metal model process type, and identifying the corresponding tool body type according to the current sheet metal model process type; and identifying the line and surface features corresponding to each tool body type according to the tool body type corresponding to each process type; defining and naming the line and surface features according to the process type and the corresponding tool body type according to the naming rules, and classifying and packaging them according to the sheet metal model process type, and storing them in a tool library. The tool body definition method based on feature recognition can effectively improve the quality and efficiency of the sheet metal forming simulation design of automobile cover parts, wherein the naming rules based on automatic recognition of the tool body are the process tool body automatic definition rapid design, which greatly shortens the design time and reduces process design anomalies.

Description

Technical Field

[0001] The present invention relates to the technical field of sheet metal production, and in particular to a tool body definition method based on feature recognition. Background Art

[0002] With the continuous development of the automobile industry, automobile covering parts products are becoming more and more complex and the replacement speed is fast, which puts high demands on the update speed of automobile covering parts product structure. The sheet metal parts in automobile covering parts are multi-process formed parts, which generally undergo multiple forming processes such as drawing, bending, trimming, punching, flanging, etc. The process of designing each forming process according to the part model is called sheet metal process model design.

[0003] The disclosure discloses a process method for controlling the shaping quality of the B-pillar side of a rear door outer panel with publication number CN112007970A. The stamping of the B-pillar sheet of the rear door outer panel includes the following processes: the first process is drawing: raising the hinge mounting surface along the direction of the vehicle body as a process supplement surface, and reducing the drawing height at the sharp point; the second process is trimming: trimming off all process supplements outside the sheet; the third process is flanging: shaping the B-pillar side drawing process supplement surface to the hinge mounting surface of the product, and optimizing the shaping process, adding constraints, and solving the problems of cracking and wrinkling of the product; the fourth process is straight flanging plus oblique flanging: flanging the pressed edge of the B-pillar side into place.

[0004] At present, the tool body definition of sheet metal forming simulation process is all manually specified. For complex products, the process information contained will be relatively large, and it is easy to make mistakes during the definition process, which will affect the operation of the simulation program, thereby increasing the process design cycle and complexity, thereby reducing design efficiency. Summary of the invention

[0005] In view of this, the present invention proposes a tool body definition method based on feature recognition, which can define each sequence tool body according to rules, shorten the design cycle, and effectively improve the quality and efficiency of automobile cover sheet forming simulation design.

[0006] The technical solution of the present invention is implemented as follows: The present invention provides a tool body definition method based on feature recognition, comprising the following steps:

[0007] S1, input sheet metal model;

[0008] S2, obtaining the current sheet metal model process type, identifying the corresponding tool body type according to the current sheet metal model process type; and identifying the line and surface features corresponding to each tool body type according to the tool body type corresponding to each process type;

[0009] S3, according to the process type and the corresponding tool body type, define and name the line and surface features according to the naming rules, and classify and package them according to the sheet metal model process type and store them in the tool library.

[0010] On the basis of the above technical solution, preferably, the sheet metal model in step S1 includes process surfaces, process lines and stamping coordinate system features.

[0011] On the basis of the above technical solution, preferably, the current sheet metal model process type is obtained in step S2, wherein the sheet metal model process type includes a drawing process, a punching process, a flanging process and a forming process, and the drawing process, the punching process, the flanging process and the forming process are performed in sequence.

[0012] On the basis of the above technical solution, preferably, the step S2 identifies the corresponding tool body type according to the current sheet metal model process type, including identifying the tool body type corresponding to the drawing process, identifying the tool body type corresponding to the punching process, identifying the tool body type corresponding to the flanging process, and identifying the tool body type corresponding to the forming process.

[0013] On the basis of the above technical solution, preferably, the identifying the type of tool body corresponding to the drawing process, wherein the type of tool body corresponding to the drawing process includes a die, a punch and a blank holder, comprises the following sub-steps:

[0014] Obtain the sheet metal model body of the drawing process;

[0015] Obtain the stamping coordinate system feature, and determine the projection of the punch and die along the stamping direction according to the spatial position along the stamping coordinate system feature direction. The sheet metal model body that is mapped first is the die, and the sheet metal model body that is mapped later is the punch.

[0016] The non-die sheet that contacts the punch is the blank holder.

[0017] On the basis of the above technical solution, preferably, the identification of the tool body type corresponding to the punching and repairing process, wherein the tool body type corresponding to the punching and repairing process includes an upper pressing material, a lower knife block, a trimming line, a slider direction line and a punching line, comprises the following sub-steps:

[0018] The sheet metal model piece with the largest area in the punching process is obtained. The sheet metal model piece in the punching process is the upper pressing material, and all pieces except the upper pressing material are lower cutting blocks.

[0019] On the basis of the above technical solution, preferably, the identification of the tool body type corresponding to the flanging shaping process, wherein the tool body type corresponding to the flanging shaping process includes an upper pressing material, a lower pressing material, an upper knife block, a lower knife block and a slider direction line, comprises the following sub-steps:

[0020] Obtaining a sheet metal model body for a flanging shaping process;

[0021] The areas of the various sheets of the sheet metal model in the flanging shaping process are compared, and the sheets ranked first and second in area are the upper pressing sheet and the lower pressing sheet;

[0022] The upper pressing material and the lower pressing material are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is projected along the stamping direction first is the upper pressing material, and the sheet that is mapped later is the lower pressing material.

[0023] Except for the upper pressing material and the lower pressing material, according to the spatial position relationship, the upper knife block is located above the upper pressing material along the punching direction;

[0024] Except for the upper pressing material, the lower pressing material and the upper knife block, all the sheet bodies are the lower knife blocks.

[0025] On the basis of the above technical solution, preferably, the identification of the tool body type corresponding to the forming process, wherein the identification of the tool body type corresponding to the forming process includes a concave die, a convex die, an upper pressing material and a lower pressing material, comprises the following sub-steps:

[0026] Obtaining a sheet metal model piece of a forming process;

[0027] The areas of the various pieces of the sheet metal model in the forming process are compared, and the pieces ranked first and second in area are the punch and the die;

[0028] The punch and die are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is projected along the stamping direction first is the die, and the sheet that is mapped later is the punch.

[0029] The upper pressing material and the lower pressing material are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is first mapped along the stamping direction is the upper pressing material, and the sheet that is mapped later is the lower pressing material.

[0030] On the basis of the above technical solution, preferably, in step S2, according to the tool body type corresponding to each process type, the line and surface features corresponding to each tool body type are identified, wherein the identification of the line and surface features corresponding to each tool body type includes process line identification and process surface identification, and the process line identification includes trimming line, slide direction line and punching line feature identification;

[0031] The trimming line feature recognition of the process line includes the following steps: obtaining sheet metal model pieces and obtaining all boundaries on each piece; extracting the boundaries to obtain curves; arranging the curves in ascending order of length, and obtaining the maximum contour line as the trimming line;

[0032] The punching line feature recognition of the process line includes the following steps: traversing all curves except the maximum curve in sequence, and calculating the minimum distance between the endpoints of each curve; if the minimum distance is zero, it is a closed area punching line; if the minimum distance is not zero and coincides with the position corresponding to the trimming line, it is a non-closed area punching line;

[0033] The slider direction line feature recognition of the process line comprises the following steps: traversing whether there is a straight line around the identified process line, if so, obtaining its slider direction line, and classifying the corresponding process line and slider direction line into a group;

[0034] The process surface is formed by splicing the seed surface and adjacent surfaces according to preset rules, and the process surface features are identified according to the preset rules.

[0035] On the basis of the above technical solution, preferably, in step S3, the line and surface feature definitions are named according to the process type and the corresponding tool body type according to the naming rules, and are classified and packaged according to the sheet metal model process type and stored in the tool library, wherein:

[0036] The drawing process is named DR, the die tool body type in the drawing process is named TM, the punch tool body type in the drawing process is named AM, the blank holder tool body type in the drawing process is named YBQ, and the stamping coordinate system tool body type in the drawing process is named ZBX;

[0037] The punching process is named TR, the upper pressing tool body type in the punching process is named SYL, the lower cutter tool body type in the punching process is named XDK, the trimming line tool body type in the punching process is named XBX, the stamping coordinate system tool body type in the punching process is named ZBX, the slider direction tool body type in the punching process is named HKFX, and the punching line tool body type in the punching process is named CKX;

[0038] The flanging shaping process is named FL, the upper pressing tool body type in the flanging shaping process is named SYL, the lower pressing tool body type in the flanging shaping process is named XYL, the slider direction tool body type in the flanging shaping process is named HKFX, the stamping coordinate system tool body type in the flanging shaping process is named ZBX, the upper cutter block tool body type in the flanging shaping process is named SDK, and the lower cutter block tool body type in the flanging shaping process is named XDK;

[0039] The forming process is named RST, the die tool body type in the forming process is named AM, the stamping coordinate system tool body type in the forming process is named ZBX, the punch tool body type in the forming process is named TM, the upper pressing tool body type in the forming process is named SYL, and the lower pressing tool body type in the forming process is named XYL;

[0040] If there are multiple line and surface feature information in the tool body type in each process, they are numbered in sequence using serial numbers;

[0041] The process model of the sheet metal model includes one mold with one piece and one mold with two pieces. When the sheet metal forming simulation process model is one mold with one piece, it is named L. When the sheet metal forming simulation process model is one mold with two pieces, it is named L and R separately.

[0042] The naming rule of process tool body is process name_process model_tool body name+serial number;

[0043] The corresponding line and surface features are encapsulated in the corresponding tool body type, and classified and packaged according to the corresponding sheet metal model process type and stored in the tool library.

[0044] The tool body definition method based on feature recognition of the present invention has the following beneficial effects compared with the prior art:

[0045] (1) By establishing a unified naming standard for tool bodies, tool bodies for different processes are automatically identified, and then the program automatically defines the process tool bodies to achieve the purpose of rapid simulation design, effectively improving the quality and efficiency of automobile panel sheet forming simulation design. The naming rules based on automatic identification of tool bodies are used to automatically define the process tool bodies for rapid design, which greatly shortens the design time and reduces process design anomalies;

[0046] (2) The final pressing tool body is selected through shape analysis rules. The three dimensions of complexity, convexity and concavity, and symmetry of the sheet are combined for analysis, which can more accurately determine the type of pressing tool body and improve the accuracy of tool body recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 A schematic diagram of the structure of a device in a hardware operating environment involved in an embodiment of the present invention;

[0049] Figure 2 A schematic flow chart of a tool body definition method based on feature recognition according to the present invention;

[0050] Figure 3 A system structure diagram is defined for the tool body based on feature recognition of the present invention;

[0051] Figure 4 A schematic diagram of a tool body for a drawing process according to a tool body definition method based on feature recognition of the present invention;

[0052] Figure 5A schematic diagram of a tool body for a punching process of a tool body definition method based on feature recognition according to the present invention;

[0053] Figure 6 A schematic diagram of a tool body for a flanging process according to a tool body definition method based on feature recognition of the present invention;

[0054] Figure 7 A schematic diagram of a tool body for a forming process of a tool body definition method based on feature recognition of the present invention;

[0055] Figure 8 It is a schematic diagram of edge concavity judgment of the tool body definition method based on feature recognition of the present invention. DETAILED DESCRIPTION

[0056] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] like Figure 1 As shown, the device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), an input unit such as a keyboard (Keyboard), and the optional user interface 1003 may also include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a wireless fidelity (WIreless-FIdelity, WI-FI) interface). The memory 1005 may be a high-speed random access memory (Random Access Memory, RAM) memory, or a stable non-volatile memory (Non-Volatile Memory, NVM), such as a disk memory. The memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0058] Those skilled in the art will understand that Figure 1 The structure shown in the figure does not constitute a limitation of the device. In actual applications, the device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0059] like Figure 1As shown, the memory 1005 as a medium may include an operating system, a network communication module, a user interface module, and a tool body definition method program based on feature recognition.

[0060] exist Figure 1 In the device shown, the network interface 1004 is mainly used to establish a communication connection between the device and a server that stores all data required in the feature recognition-based tool body definition method system; the user interface 1003 is mainly used to interact with the user for data; the processor 1001 and the memory 1005 in the feature recognition-based tool body definition method device of the present invention can be set in the feature recognition-based tool body definition method device, and the feature recognition-based tool body definition method device calls the feature recognition-based tool body definition method program stored in the memory 1005 through the processor 1001, and executes the feature recognition-based tool body definition method provided by the implementation of the present invention.

[0061] like Figure 2 As shown, a tool body definition method based on feature recognition of the present invention comprises the following steps:

[0062] S1, input sheet metal model, which includes process surface, process line and stamping coordinate system features;

[0063] It should be noted that process surface refers to the surface that needs to be operated or processed specifically during the sheet metal processing. Process line refers to the line used to define and describe the shape, size and features of parts during the sheet metal processing. The line includes bending lines, cutting lines, punching lines, etc. They determine the final shape and appearance of sheet metal parts. The stamping coordinate system feature is a reference system used to describe the position and orientation of sheet metal parts during the stamping process. The stamping coordinate system feature usually includes a reference plane, a reference axis and an origin to facilitate the determination of the exact position and orientation of sheet metal parts on the stamping machine. In the sheet metal model, the stamping coordinate system feature is usually created by the drawing software system and is interrelated with features such as process surface and process line.

[0064] S2, obtaining the current sheet metal model process type, the sheet metal model process type includes a drawing process, a punching process, a flanging process and a forming process, and the drawing process, the punching process, the flanging process and the forming process are performed in sequence, and the corresponding tool body type is identified according to the current sheet metal model process type, including identifying the tool body type corresponding to the drawing process, identifying the tool body type corresponding to the punching process, identifying the tool body type corresponding to the flanging process and identifying the tool body type corresponding to the forming process; and according to the tool body type corresponding to each process type, identifying the line and surface features corresponding to each tool body type;

[0065] It should be noted that the system first reads the data of the sheet metal model and parses the process information therein. According to the order and type of the process information, the system determines the process types contained in the current model, namely, the drawing process, the trimming and punching process, the flanging and shaping process, and the forming process. Among them, the drawing process is used to shape the sheet metal material into the desired shape. After the system identifies the drawing process, it determines the corresponding drawing die type, such as the die, the punch and the pressure ring. The trimming and punching process is used to trim and punch the drawn sheet metal parts. The flanging and shaping process is used to flanging and shaping the edges of the sheet metal parts. The forming process is used to shape the sheet metal parts into the final shape.

[0066] like Figure 4 As shown, in this example, identifying the tool body type corresponding to the drawing process, wherein the tool body type corresponding to the drawing process includes a die, a punch, and a blank holder, includes the following sub-steps:

[0067] Obtain the sheet metal model body of the drawing process;

[0068] Obtain the stamping coordinate system feature, and determine the projection of the punch and die along the stamping direction according to the spatial position along the stamping coordinate system feature direction. The sheet metal model body that is mapped first is the die, and the sheet metal model body that is mapped later is the punch.

[0069] The non-die sheet that contacts the punch is the blank holder.

[0070] It should be noted that, first, the sheets related to the drawing process are extracted from the sheet metal model. These sheets represent the parts of the sheet metal that need to be deformed during the drawing process. The system will map the direction of the stamping coordinate system to the sheet metal model, and determine which sheet metal model sheets are mapped first based on the direction. These sheets are the die. In the actual stamping process, the die is fixed on the punch, and the punch moves downward to cooperate with the die to complete the drawing. The sheet metal model sheet mapped later is the punch. The punch moves downward during the stamping process, contacts the sheet metal material in the die and applies pressure to deform it. The blank holder plays the role of fixing the edge of the sheet metal material during the drawing process to prevent the material from moving or wrinkling during the drawing process. After the system first determines the position and shape of the punch, the system searches for sheets that are in contact with the punch but are not identified as dies. These sheets are the blank holders. They are usually located at the edge of the sheet metal material and work together with the punch and die to complete the drawing process.

[0071] In addition, the specific steps of the system searching for sheets that are in contact with the punch but not identified as the die include: first, determining the boundary of the punch based on the identified punch sheet, and extracting the boundary contour of the punch. The system can determine the specific shape and size of the punch by identifying these contours, and then, by traversing all sheets in the sheet metal model, searching for sheets adjacent to the punch. These sheets may be in direct contact with the punch, or may be adjacent to the punch but not in direct contact. For each sheet, the system can check whether it intersects or is adjacent to the boundary of the punch. In the process of searching for sheets, the system excludes sheets that have been identified as the die, because the blank holder is a sheet that is in contact with the punch but is not a die. After excluding the die sheet, the system is left with sheets that are in contact with the punch but not identified as the die, and these sheets are the blank holders.

[0072] like Figure 5 As shown, the tool body type corresponding to the punching process is identified, wherein the tool body type corresponding to the punching process includes an upper pressing material, a lower knife block, a trimming line, a slider direction line and a punching line, including the following sub-steps: obtaining the sheet metal model piece with the largest area in the punching process, the sheet metal model piece of the punching process is the upper pressing material, and all pieces except the upper pressing material are the lower knife block.

[0073] like Figure 6 As shown, the tool body type corresponding to the flanging shaping process in this example is identified, wherein the tool body type corresponding to the flanging shaping process includes an upper pressing material, a lower pressing material, an upper knife block, a lower knife block and a slider direction line, including the following sub-steps:

[0074] Obtain a sheet metal model piece of a flanging shaping process, wherein the model includes multiple pieces, each representing a tool or workpiece of a different part;

[0075] The areas of the various sheets of the sheet metal model in the flanging shaping process are compared. The sheets ranked first and second in area are the upper pressing sheet and the lower pressing sheet. Since the sheets with larger areas are usually used to carry and transmit the punching force, the type of the pressing tool body is determined based on the area.

[0076] Among them, the stamping direction is first determined, and the projection area of ​​each sheet in the stamping direction is calculated. The sheets with the first two projection areas are the type of the punching tool body. However, in this process, if there are multiple similar sheets projected in the stamping direction and they are ranked in the first two, the shape of the sheet is further considered, the complexity of the boundary line of the sheet is analyzed, the boundary contour line of the sheet is obtained, the number of inflection points N in the boundary contour line is extracted, and then the curvature analysis tool is used to obtain the average curvature value K between the two inflection points. According to the average curvature value, it can be judged whether the line segment is a straight line or a curve. If K is greater than If K=0, it is a curve, and if K=0, it is a straight line. Then, the number of straight lines Z and curves Q is counted respectively. According to the statistics of straight lines and curves, the proportion of curves in the total line segment is determined, and then the central axis of the boundary contour line is determined. The central axis is used as the dividing line to obtain the continuous line segment feature information on both sides in turn. The line segment feature information includes the angle and length information of the line segment. The continuous line segment feature information on both sides is added to the two recognition feature vector sets in turn. After the similarity calculation of the two recognition feature vector sets is performed, the symmetry value G is obtained, and the complexity F of the sheet is calculated. The calculation expression is:

[0077] S = W1*N+W2*Q / (Z+Q)+W3*G;

[0078] W1 is the weight of the number of inflection points in the boundary contour line, W2 is the weight of the proportion of the curve in the total line segment, and W3 is the weight of the symmetry value index, W1+W2+W3=1.

[0079] According to the calculated complexity F of the multiple sheets ranked in the first two positions, the complexity values ​​are compared, and the sheet with the largest complexity value is selected as the final pressing sheet.

[0080] The final pressing tool body is selected through shape analysis rules. The three dimensions of complexity, convexity and concavity, and symmetry of the sheet are combined for analysis, which can more accurately determine the type of pressing tool body and reduce the possibility of misjudgment and missed judgment.

[0081] The upper pressing material and the lower pressing material are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is projected along the stamping direction first is the upper pressing material, and the sheet that is mapped later is the lower pressing material.

[0082] Except for the upper pressing material and the lower pressing material, according to the spatial position relationship, the upper knife block is located above the upper pressing material along the punching direction;

[0083] Except for the upper pressing material, the lower pressing material and the upper knife block, all the sheet bodies are the lower knife blocks.

[0084] It should be noted that the slider direction line is used to indicate the movement direction and path of the slider during the stamping process. The system determines the movement trajectory and direction of the slider by analyzing the animation or simulation data of the stamping process. After determining the movement trajectory of the slider, the system can extract the slider direction line and use a straight line to represent the movement direction of the slider during the stamping process, which is the slider direction line.

[0085] like Figure 7 As shown, in this example, the tool body type corresponding to the forming process is identified, wherein the tool body type corresponding to the forming process includes a concave die, a convex die, an upper pressing material, and a lower pressing material, including the following sub-steps:

[0086] Obtaining a sheet metal model piece of a forming process;

[0087] The areas of the various pieces of the sheet metal model in the forming process are compared, and the pieces ranked first and second in area are the punch and the die;

[0088] The punch and die are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is projected along the stamping direction first is the die, and the sheet that is mapped later is the punch.

[0089] The upper pressing material and the lower pressing material are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is first mapped along the stamping direction is the upper pressing material, and the sheet that is mapped later is the lower pressing material.

[0090] In step S2 of this embodiment, according to the tool body type corresponding to each process type, the line and surface features corresponding to each tool body type are identified, wherein the line and surface features corresponding to each tool body type include process line identification and process surface identification, and the process line identification includes trimming line, slide direction line and punching line feature identification;

[0091] The trimming line feature recognition of the process line includes the following steps: obtaining the sheet metal model body and all the boundaries on each sheet body; extracting the boundaries to obtain curves; arranging the curves in ascending order of length, and obtaining the maximum contour line as the trimming line;

[0092] The punching line feature recognition of the process line includes the following steps: traverse all curves except the largest curve in turn, and calculate the minimum distance between the endpoints of each curve; if the minimum distance is zero, it is a closed area punching line; if the minimum distance is not zero and coincides with the position corresponding to the trimming line, it is a non-closed area punching line, which is a partial punching or grooving;

[0093] The slider direction line feature recognition of the process line includes the following steps: traversing whether there is a straight line around the identified process line, if so, obtaining its slider direction line, and classifying its corresponding process line and slider direction line into a group, so as to facilitate the determination of the subsequent punching processing direction;

[0094] The process surface is formed by splicing the seed surface and adjacent surfaces according to preset rules. The process surface features are identified according to the preset rules. First, a surface is selected as the seed surface, and then the connection relationship between the seed surface and its adjacent surfaces is judged one by one to see whether it meets the rules of a certain external feature. If so, a valid external feature is identified.

[0095] Among them, the convexity of the edge is an important feature of the edge, and this feature is often used when establishing feature recognition rules. According to the geometric relationship, the edge can be divided into convex edges, concave edges, tangent edges, and mixed edges.

[0096] like Figure 8 As shown, the common edge of two adjacent faces F1 and F2 is E, and the normals of the two faces at the midpoint of the common edge are N1 and N2 respectively. The steps to determine the concavity of the edge are:

[0097] S201, calculate the normals N1 and N2 of the two faces at the midpoint of the common edge. If N1 and N2 are in the same direction, E is a tangent edge, otherwise execute S202;

[0098] S202, if neither F1 nor F2 is a plane, the common edge E is a mixed edge, otherwise execute S203;

[0099] S203, assuming F1 is a plane, calculate a vector V according to the right-hand rule, where:

[0100] V = N1 × N2;

[0101] S204, calculate the direction N of F1 at the common edge E e , note that F1 is the left-hand vector of the cross product in step 3, and the direction of the edge is defined as walking along this direction on the face, with the face on the left-hand side;

[0102] S205, calculate V and N e The angle α formed, if α<π / 2, E is a convex edge, if α>π / 2, E is a concave edge.

[0103] Among them, there are many free-form surfaces in sheet metal parts. The type and characteristic parameters of the surface can be accurately obtained through the multi-point sampling method. From the perspective of surface formation and curvature distribution, the characteristic surfaces can be divided into planes, cylinders, cones, tori and spheres.

[0104] Randomly select a certain number of points on the surface. If the normals of these points are consistent, the surface is considered to be a plane. The normal of a plane can be taken as the normal at any point on the surface.

[0105] The minimum radius of curvature at any point on a cylindrical surface is the radius of the cylindrical surface, and the maximum radius of curvature is infinite. If a certain number of points are randomly selected on the surface, and the minimum radius of curvature of the surface at these points is equal, and the maximum radius of curvature is infinite, then the surface is considered to be a cylindrical surface; if a point is randomly selected on the surface and the distance of the radius is offset along the normal direction of the point, a point on the axis of the cylindrical surface can be obtained. The direction of the axis can be determined based on the two points on the axis.

[0106] The conical surface is the result of a generatrix rotating around an axis. The angle between the normal of any point on the surface and the central axis is the same. Take any three points on the surface, and the direction of the central axis can be determined based on the three normals. Then, randomly select some points on the surface to calculate the angle between the normal and the central axis. If the angles are all equal, the surface is considered to be a conical surface.

[0107] A torus is a surface obtained by sweeping a circular arc around a free curve. If a certain number of points are randomly selected on the surface, and one of the two radii of curvature at any point on the surface is equal and the other is not infinite, then the surface is considered to be a torus.

[0108] If we randomly select a certain number of points on the surface and the two radii of curvature of the surface at these points are equal, then the surface is a sphere.

[0109] S3, according to the process type and the corresponding tool body type, define and name the line and surface features according to the naming rules, and classify and package them according to the sheet metal model process type and store them in the tool library.

[0110] Among them, the drawing process is named DR, the die tool body type in the drawing process is named TM, the punch tool body type in the drawing process is named AM, the blank holder tool body type in the drawing process is named YBQ, and the stamping coordinate system tool body type in the drawing process is named ZBX;

[0111] The name of the punching process is TR, the upper pressing tool body type in the punching process is SYL, the lower cutter tool body type in the punching process is XDK, the trimming line tool body type in the punching process is XBX, the stamping coordinate system tool body type in the punching process is ZBX, the slider direction tool body type in the punching process is HKFX, and the punching line tool body type in the punching process is CKX;

[0112] The name of the flanging shaping process is FL, the upper pressing tool body type in the flanging shaping process is named SYL, the lower pressing tool body type in the flanging shaping process is named XYL, the slider direction tool body type in the flanging shaping process is named HKFX, the stamping coordinate system tool body type in the flanging shaping process is named ZBX, the upper cutter block tool body type in the flanging shaping process is named SDK, and the lower cutter block tool body type in the flanging shaping process is named XDK;

[0113] The name of the forming process is RST, the name of the die tool body type in the forming process is AM, the name of the stamping coordinate system tool body type in the forming process is ZBX, the name of the punch tool body type in the forming process is TM, the name of the upper pressing tool body type in the forming process is SYL, and the name of the lower pressing tool body type in the forming process is XYL;

[0114] If there are multiple line and surface feature information in the tool body type in each process, they are numbered in sequence using serial numbers; the numbering rules for different tool bodies are shown in the following table:

[0115]

[0116] Among them, the process model of the sheet metal model includes one mold with one piece and one mold with two pieces. When the sheet metal forming simulation process model is one mold with one piece, it is named L. When the sheet metal forming simulation process model is one mold with two pieces, it is named L and R separately; the representation is shown in the following table:

[0117] Process Type Representation method One piece L One mold, two pieces L, R

[0118] The naming rule of process tool body is process name_process model_tool body name+serial number;

[0119] The complete tool body of the drawing process is shown as follows:

[0120] One mold for one piece: DR_L_AM01, DR_L_TM01, DR_L_YBQ01, DR_L_ZBX01;

[0121] One mold, two pieces: DR_L_AM01, DR_L_TM01, DR_L_YBQ01, DR_L_ZBX01, DR_R_AM01, DR_R_TM01, DR_R_YBQ01, DR_R_ZBX01.

[0122] The complete tool body of the repair and punching process is shown as follows:

[0123] One model: TR_L_SYL01, TR_L_XDK01, TR_L_ZBX01, TR_L_XBX01, TR_L_HKFX01, TR_L_HKFX02, TR_L_HKFX03, TR_L_CKX01, TR_L_CKX02, TR_L_CKX03, TR_L_CKX04, TR_L_CKX05;

[0124] One mold, two pieces: TR_L_SYL01, TR_L_XDK01, TR_L_ZBX01, TR_L_XBX01, TR_L_HKFX01, TR_L_HKFX02, TR_L_HKFX03, TR_L_CKX01, TR_L_CKX02, TR_L_CKX03, TR_L_CKX04, TR_L_CKX05, TR_R_SYL01, TR_R_XDK01, TR_R_ZBX01, TR_R_XBX01, TR_R_HKFX01, TR_R_HKFX02, TR_R_HKFX03, TR_R_CKX01, TR_R_CKX02, TR_R_CKX03, TR_R_CKX04, TR_R_CKX05;

[0125] The complete tool body of the flanging shaping process is shown as follows:

[0126] One model: FL_L_SYL01, FL_L_XYL01, FL_L_ZBX01, FL_L_SDK01, FL_L_SDK02, FL_L_SDK03, FL_L_HKFX01, FL_L_HKFX02, FL_L_HKFX03, FL_L_XDK01, FL_L_XDK02, FL_L_XDK03;

[0127] Two pieces of one mold: FL_L_SYL01, FL_L_XYL01, FL_L_ZBX01, FL_L_SDK01, FL_L_SDK02, FL_L_SDK03, FL_L_HKFX01, FL_L_HKFX02, FL_L_HKFX03, FL_L_XDK01, FL_L_XDK02, FL_L_XDK 03. FL_R_SYL01, FL_R_XYL01, FL_R_ZBX01, FL_R_SDK01, FL_R_SDK02, FL_R_SDK03, FL_R_HKFX01, FL_R_HKFX02, FL_R_HKFX03, FL_R_XDK01, FL_R_XDK02, FL_R_XDK03;

[0128] The complete tool body of the forming process is shown as follows:

[0129] One mold for one piece: RST_L_SYL01, RST_L_XYL01, RST_L_TM01, RST_L_AM01, RST_L_ZBX01;

[0130] One mold, two pieces: RST_L_SYL01, RST_L_XYL01, RST_L_TM01, RST_L_AM01, RST_L_ZBX01, RST_R_SYL01, RST_R_XYL01, RST_R_TM01, RST_R_AM01, RST_R_ZBX01;

[0131] The corresponding line and surface features are encapsulated in the corresponding tool body type, and classified and packaged according to the corresponding sheet metal model process type and stored in the tool library.

[0132] After naming the tool body model files prepared for each sequence as required, they are imported into the platform with one click, and the system automatically defines the tool body for each sequence according to the rules.

[0133] The present invention can effectively improve the quality and efficiency of the simulation design of automobile cover sheet forming, wherein the naming rules based on the automatic identification of the tool body are used to automatically define the rapid design of the process tool body, which greatly shortens the design time and reduces process design anomalies.

[0134] In addition, if Figure 3 As shown, the embodiment of the present invention also proposes a tool body definition system based on feature recognition, the system comprising:

[0135] Input module, used to input sheet metal models;

[0136] The recognition module is used to obtain the current sheet metal model process type, identify the corresponding tool body type according to the current sheet metal model process type; and identify the line and surface features corresponding to each tool body type according to the tool body type corresponding to each process type;

[0137] The naming definition module is used to define and name line and surface features according to the process type and the corresponding tool body type according to the naming rules, and classify and package them according to the sheet metal model process type and store them in the tool library.

[0138] In addition, it should be noted that the device embodiments described above are merely illustrative and do not limit the scope of protection of the present invention. In practical applications, technicians in this field can select some or all of the modules according to actual needs to achieve the purpose of the present embodiment, and no restrictions are made here.

[0139] In addition, for technical details that are not described in detail in this embodiment, reference can be made to the tool body definition method based on feature recognition provided in any embodiment of the present invention, and will not be repeated here.

[0140] In addition, the present invention provides a computer medium, which is a computer medium, and a tool body definition method program based on feature recognition is stored on the computer medium. When the tool body definition method program based on feature recognition is executed by a processor, the steps of the tool body definition method based on feature recognition as described above are implemented.

[0141] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A tool body definition method based on feature recognition, characterized in that: The following steps are involved: S1, inputting a sheet metal model, wherein the sheet metal model includes process surfaces, process lines and stamping coordinate system features; S2, obtaining the current sheet metal model process type, identifying the corresponding tool body type according to the current sheet metal model process type; and identifying the line and surface features corresponding to each tool body type according to the tool body type corresponding to each process type; the sheet metal model process type includes a drawing process, a punching process, a flanging process and a forming process, and the drawing process, the punching process, the flanging process and the forming process are performed in sequence; Identify the corresponding tool body type according to the process type of the current sheet metal model, including identifying the tool body type corresponding to the drawing process, identifying the tool body type corresponding to the punching process, identifying the tool body type corresponding to the flanging process, and identifying the tool body type corresponding to the forming process; The identifying of the tool body type corresponding to the flanging shaping process, wherein the tool body type corresponding to the flanging shaping process includes an upper pressing material, a lower pressing material, an upper knife block, a lower knife block and a slider direction line, includes the following sub-steps: Obtaining a sheet metal model body for a flanging shaping process; The areas of the various sheets of the sheet metal model in the flanging shaping process are compared, and the sheets ranked first and second in area are the upper pressing sheet and the lower pressing sheet; The upper pressing material and the lower pressing material are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is projected along the stamping direction first is the upper pressing material, and the sheet that is mapped later is the lower pressing material. Except for the upper pressing material and the lower pressing material, according to the spatial position relationship, the upper knife block is located above the upper pressing material along the punching direction; Except for the upper pressing material, the lower pressing material and the upper knife block, all the sheets are the lower knife blocks; The identification of line and surface features corresponding to each tool body type includes process line identification and process surface identification, and the process line identification includes trimming line, slide direction line and punching line feature identification; The trimming line feature recognition of the process line includes the following steps: obtaining the sheet metal model body and all the boundaries on each sheet body; extracting the boundaries to obtain curves; arranging the curves in ascending order of length, and obtaining the maximum contour line as the trimming line; The punching line feature recognition of the process line includes the following steps: traversing all curves except the largest curve in turn, and calculating the minimum distance between the endpoints of each curve; if the minimum distance is zero, it is a closed area punching line; if the minimum distance is not zero and coincides with the position corresponding to the trimming line, it is a non-closed area punching line; The slider direction line feature recognition of the process line comprises the following steps: traversing whether there is a straight line around the identified process line, if so, obtaining its slider direction line, and classifying the corresponding process line and slider direction line into a group; The process surface is formed by splicing the seed surface and the adjacent surface according to the preset rules, and the process surface features are identified according to the preset rules; S3, according to the process type and the corresponding tool body type, define and name the line and surface features according to the naming rules, and classify and package them according to the sheet metal model process type and store them in the tool library.

2. The method for defining a tool body based on feature recognition according to claim 1, characterized in that: The identifying of the tool body type corresponding to the drawing process, wherein the tool body type corresponding to the drawing process includes a die, a punch and a blank holder, comprises the following sub-steps: Obtain the sheet metal model body of the drawing process; Obtain the stamping coordinate system feature, and determine the projection of the punch and die along the stamping direction according to the spatial position along the stamping coordinate system feature direction. The sheet metal model body that is mapped first is the die, and the sheet metal model body that is mapped later is the punch. The non-die sheet that contacts the punch is the blank holder.

3. The method for defining a tool body based on feature recognition according to claim 2, characterized in that: The identification of the tool body type corresponding to the punching process, wherein the tool body type corresponding to the punching process includes an upper pressing material, a lower knife block, a trimming line, a slider direction line and a punching line, includes obtaining the sheet metal model piece with the largest area in the punching process, the sheet metal model piece of the punching process is the upper pressing material, and all pieces except the upper pressing material are the lower knife block.

4. The method for defining a tool body based on feature recognition according to claim 3, characterized in that: The identifying the tool body type corresponding to the forming process, wherein the tool body type corresponding to the forming process includes a concave die, a convex die, an upper pressing material and a lower pressing material, comprises the following sub-steps: Obtaining a sheet metal model body of a forming process; The areas of the various pieces of the sheet metal model in the forming process are compared, and the pieces ranked first and second in area are the punch and the die; The punch and die are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is projected along the stamping direction first is the die, and the sheet that is mapped later is the punch. The upper pressing material and the lower pressing material are determined according to the spatial position along the direction of the stamping coordinate system. The sheet that is first mapped along the stamping direction is the upper pressing material, and the sheet that is mapped later is the lower pressing material.

5. The method for defining a tool body based on feature recognition according to claim 4, characterized in that: In step S3, the line and surface feature definitions are named according to the process type and the corresponding tool body type according to the naming rules, and are classified and packaged according to the sheet metal model process type and stored in the tool library, wherein: The drawing process is named DR, the die tool body type in the drawing process is named TM, the punch tool body type in the drawing process is named AM, the blank holder tool body type in the drawing process is named YBQ, and the stamping coordinate system tool body type in the drawing process is named ZBX; The punching process is named TR, the upper pressing tool body type in the punching process is named SYL, the lower cutter tool body type in the punching process is named XDK, the trimming line tool body type in the punching process is named XBX, the stamping coordinate system tool body type in the punching process is named ZBX, the slider direction tool body type in the punching process is named HKFX, and the punching line tool body type in the punching process is named CKX; The flanging shaping process is named FL, the upper pressing tool body type in the flanging shaping process is named SYL, the lower pressing tool body type in the flanging shaping process is named XYL, the slider direction tool body type in the flanging shaping process is named HKFX, the stamping coordinate system tool body type in the flanging shaping process is named ZBX, the upper cutter block tool body type in the flanging shaping process is named SDK, and the lower cutter block tool body type in the flanging shaping process is named XDK; The forming process is named RST, the die tool body type in the forming process is named AM, the stamping coordinate system tool body type in the forming process is named ZBX, the punch tool body type in the forming process is named TM, the upper pressing tool body type in the forming process is named SYL, and the lower pressing tool body type in the forming process is named XYL; If there are multiple line and surface feature information in the tool body type in each process, they are numbered in sequence using serial numbers; The process model of the sheet metal model includes one mold with one piece and one mold with two pieces. When the sheet metal forming simulation process model is one mold with one piece, it is named L. When the sheet metal forming simulation process model is one mold with two pieces, it is named L and R separately. The naming rule of process tool body is process name_process model_tool body name+serial number; The corresponding line and surface features are encapsulated in the corresponding tool body type, and classified and packaged according to the corresponding sheet metal model process type and stored in the tool library.

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