CN117931959B - Drawing forming parameter acquisition method and machine tool determination method - Google Patents
Drawing forming parameter acquisition method and machine tool determination method Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 60
- 238000006243 chemical reaction Methods 0.000 claims abstract description 158
- 238000003825 pressing Methods 0.000 claims description 29
- 239000011324 bead Substances 0.000 claims description 28
- 238000004364 calculation method Methods 0.000 claims description 23
- 238000004519 manufacturing process Methods 0.000 claims description 19
- 238000013507 mapping Methods 0.000 claims description 18
- 230000008569 process Effects 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 11
- 238000012545 processing Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 11
- 238000004088 simulation Methods 0.000 abstract description 9
- 238000013461 design Methods 0.000 abstract description 7
- 230000000875 corresponding effect Effects 0.000 description 36
- 238000000465 moulding Methods 0.000 description 8
- 230000009471 action Effects 0.000 description 5
- 238000004422 calculation algorithm Methods 0.000 description 5
- 238000009966 trimming Methods 0.000 description 4
- 230000002596 correlated effect Effects 0.000 description 3
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- 238000012417 linear regression Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 2
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Abstract
The application relates to the technical field of mold design, in particular to a drawing forming parameter acquisition method and a machine tool determination method, wherein the drawing forming parameter acquisition method comprises the following steps: acquiring part boundary contour and minimum envelope size information according to a part 3D digital model; acquiring drawing parting line length information according to the boundary contour of the part; acquiring a blank holder force according to the length information of the drawing parting line and the first conversion relation; obtaining forming force according to the blank holder force and the second conversion relation; acquiring a blank holder stroke according to the minimum envelope size information and the third conversion relation; the drawing forming parameter acquisition method can effectively solve the problems of high labor cost and low drawing forming parameter acquisition efficiency caused by the fact that drawing forming parameters are acquired in a mode that a designer needs to repeatedly adjust parameters of simulation software according to part simulation effects.
Description
Technical Field
The application relates to the technical field of mold design, in particular to a drawing forming parameter acquisition method and a machine tool determination method.
Background
In the existing mould design and manufacturing flow, drawing forming parameters (blank holder force, forming force and blank holder stroke) are important basis for judging whether the tonnage of a machine tool meets the production and manufacturing conditions of parts, so that the acquisition of the blank holder force, forming force and blank holder stroke has a very key effect, and the tonnage of the machine tool (equivalent to the determination of a target machine tool which is a machine tool required to be used in production) and the determination of a production line can be determined only after the blank holder force, forming force and blank holder stroke are acquired. The working flow of the existing drawing forming parameter acquisition method is as follows: 1. setting an initial value for the blank holder force and the blank holder stroke in simulation software according to experience of a designer, and generating a part simulation effect according to the two initial values by using the simulation software; 2. if the part simulation effect is that the part is wrinkled or cracked, the blank holder force, the blank holder stroke and other parameters (such as a draw bead coefficient, a supplement surface and the part modeling) of simulation software are required to be adjusted in a manual mode according to the calculated forming force and the target value, the step 1 is returned, and if the part simulation effect is that the part is not wrinkled and is not cracked, the step 3 is executed; 3. and taking the set value of the blank holder force at the moment as the final blank holder force and the blank holder stroke at the moment as the final blank holder stroke, and generating a corresponding forming force when the part simulation effect is that no fold and no crack occur according to the final blank holder force and the final blank holder stroke by utilizing the adjusted simulation software. Because the existing drawing forming parameter acquisition method needs to acquire drawing forming parameters in a mode that a designer repeatedly adjusts parameters of simulation software according to part simulation effects, the existing drawing forming parameter acquisition method has the problems of high labor cost and low blank holder force, forming force and blank holder stroke acquisition efficiency because the designer needs to acquire drawing forming parameters in a mode that the designer repeatedly adjusts parameters of the simulation software according to the part simulation effects.
In view of the above problems, no effective technical solution is currently available.
Disclosure of Invention
The application aims to provide a drawing forming parameter acquisition method and a machine tool determination method, which can effectively solve the problems of high labor cost and low drawing forming parameter acquisition efficiency caused by the fact that drawing forming parameters are acquired in a mode of repeatedly adjusting parameters of simulation software according to part simulation effects by a designer.
In a first aspect, the present application provides a method for obtaining a drawing forming parameter, which is applied in a drawing forming process, wherein the drawing forming parameter includes a blank holder force, a forming force and a blank holder stroke, and the drawing forming parameter obtaining method includes the following steps:
Acquiring part boundary contour and minimum envelope size information according to a part 3D digital model;
Acquiring drawing parting line length information according to the boundary contour of the part;
Acquiring a blank holder force according to the length information of the drawing parting line and the first conversion relation;
obtaining forming force according to the blank holder force and the second conversion relation;
And acquiring the stroke of the blank holder according to the minimum envelope body size information and the third conversion relation.
According to the drawing molding parameter obtaining method provided by the application, the drawing parting line length information and the minimum envelope body size information are obtained according to the 3D digital-analog of the part, the blank holder force is obtained according to the drawing parting line length information and the first conversion relation, the blank holder stroke is obtained according to the minimum envelope body size information and the third conversion relation, and the molding force is obtained according to the blank holder force and the second conversion relation.
Optionally, the first conversion relation includes a blank holder force calculation formula, where the blank holder force calculation formula is shown in formula (1):
（1）；
Wherein F Pressing represents the blank holder force, alpha represents the blank holder force coefficient, R m represents the tensile strength, delta represents the thickness of the target part corresponding to the 3D digital-analog of the part, and L Dividing into represents the drawing parting line length information.
Optionally, the second conversion relation includes a molding force calculation formula, where the molding force calculation formula is shown in formula (2):
（2）；
Wherein F Finished products represents a forming force, β represents a forming force coefficient, and F Pressing represents a blank holder force.
Optionally, the minimum envelope volume size information includes an envelope volume height, and the third conversion relation includes a bead stroke calculation formula, where the bead stroke calculation formula is shown in formula (3):
（3）；
Wherein S Edge pressing ring represents a bead stroke, γ represents a bead stroke coefficient, and H Bag(s) represents an envelope height.
Optionally, the step of obtaining the part boundary profile and the minimum envelope size information from the 3D digital-to-analog of the part includes:
acquiring part boundary contour, minimum envelope size information and part type information according to a 3D digital model of the part;
the step of obtaining the blank holder force according to the drawing parting line length information and the first conversion relation comprises the following steps:
Acquiring a corresponding first conversion relation according to the part type information;
Acquiring a blank holder force according to the length information of the drawing parting line and the first conversion relation;
The step of obtaining the forming force according to the blank holder force and the second conversion relation comprises the following steps:
acquiring a corresponding second conversion relation according to the part type information;
obtaining forming force according to the blank holder force and the second conversion relation;
The step of obtaining the edge pressing ring travel according to the minimum envelope size information and the third conversion relation comprises the following steps:
Acquiring a corresponding third conversion relation according to the part type information;
And acquiring the stroke of the blank holder according to the minimum envelope body size information and the third conversion relation.
Because the parts of the same type have the same design rule, and the parts of different types have different design rules, namely the parts of different types correspond to different first conversion relations, second conversion relations and third conversion relations, the technical scheme is equivalent to that of obtaining drawing forming parameters by utilizing the first conversion relations, the second conversion relations and the third conversion relations corresponding to the types of 3D digital-analog parts, so that the accuracy of obtaining the drawing forming parameters is further improved.
Optionally, the step of obtaining the corresponding first conversion relation according to the part type information includes:
Acquiring a corresponding first conversion relation from a pre-constructed first conversion relation database or a first conversion relation mapping table according to the part type information;
the step of obtaining the corresponding second conversion relation according to the part type information comprises the following steps:
acquiring a corresponding second conversion relation from a second conversion relation database or a second conversion relation mapping table which is built in advance according to the part type information;
The step of obtaining the corresponding third conversion relation according to the part type information comprises the following steps:
and acquiring a corresponding third conversion relation from a third conversion relation database or a third conversion relation mapping table which is built in advance according to the part type information.
Optionally, the step of obtaining the minimum envelope volume size information according to the 3D digital-to-analog of the part includes:
Acquiring a minimum envelope corresponding to the 3D digital-analog of the part based on a direction bounding box generation method;
Minimum envelope volume size information is obtained based on the minimum envelope volume.
The method for generating the direction bounding box can generate a rectangular enveloping body with the minimum volume along the extending direction of the target object, so that the obtained minimum enveloping body can be attached to the 3D digital model of the part, the size information of the minimum enveloping body can accurately reflect the size of the 3D digital model of the part, and the obtaining accuracy of the blank holder stroke is effectively improved.
Optionally, the step of obtaining drawing parting line length information from the part boundary profile includes:
projecting the boundary contour of the part based on a preset coordinate system, and performing offset processing on the projected boundary contour of the part to obtain an offset curve;
simplifying the bias curve to obtain a simplified curve;
Projecting the simplified curve to a material pressing surface of a 3D digital model of the part to obtain a drawing parting line;
and acquiring drawing parting line length information based on the drawing parting line.
In a second aspect, the present application also provides a method for determining a machine tool, which is applied in a drawing forming process, wherein drawing forming parameters include a blank holder force, a forming force and a blank holder stroke, and the method for determining a machine tool includes the steps of:
Acquiring part boundary contour and minimum envelope size information according to a part 3D digital model;
Acquiring drawing parting line length information according to the boundary contour of the part;
Acquiring a blank holder force according to the length information of the drawing parting line and the first conversion relation;
obtaining forming force according to the blank holder force and the second conversion relation;
acquiring a blank holder stroke according to the minimum envelope size information and the third conversion relation;
And determining a target machine tool according to the blank holder force, the forming force, the blank holder stroke and the preset production conditions, wherein the target machine tool is a machine tool with the blank holder force, the forming force and the blank holder stroke meeting the preset production conditions.
According to the machine tool determining method, drawing parting line length information and minimum envelope body size information are firstly obtained according to 3D digital-analog of a part, then edge pressing force is obtained according to the drawing parting line length information and the first conversion relation, edge pressing ring travel is obtained according to the minimum envelope body size information and the third conversion relation, forming force is finally obtained according to the edge pressing force and the second conversion relation, and a target machine tool is determined according to the edge pressing force, the forming force, the edge pressing ring travel and preset production conditions.
Optionally, the preset production conditions are: the blank holder force is smaller than the maximum supply tonnage of the machine tool air ejector rod, the ratio of the forming force to the stamping tonnage of the machine tool is smaller than the preset ratio, and the stroke of the blank holder is smaller than the maximum extension length of the machine tool air ejector rod.
According to the drawing forming parameter obtaining method and the machine tool determining method, drawing parting line length information and minimum envelope size information are obtained according to 3D digital models of parts, edge pressing force is obtained according to the drawing parting line length information and the first conversion relation, edge pressing ring travel is obtained according to the minimum envelope size information and the third conversion relation, and forming force is obtained according to the edge pressing force and the second conversion relation.
Drawings
Fig. 1 is a flowchart of a drawing forming parameter obtaining method according to an embodiment of the present application.
Fig. 2 is a flowchart of a machine tool determining method according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance.
In a first aspect, as shown in fig. 1, the present application provides a method for obtaining a drawing forming parameter, which is applied in a drawing forming process, where the drawing forming parameter includes a blank holder force, a forming force and a blank holder stroke, and the method for obtaining the drawing forming parameter includes the following steps:
S11, acquiring part boundary contour and minimum envelope size information according to a part 3D digital model;
S12, drawing parting line length information is obtained according to the boundary contour of the part;
S13, obtaining a blank holder force according to the length information of the drawing parting line and the first conversion relation;
s14, obtaining forming force according to the blank holder force and the second conversion relation;
s15, acquiring the stroke of the blank holder according to the minimum envelope body size information and the third conversion relation.
The drawing forming parameter obtaining method is applied to a drawing forming process, and specifically, the drawing forming process needs to use a drawing die, the drawing die is composed of a male die, a female die and a blank holder, the drawing forming process is a process that a sheet material is subjected to plastic deformation under the action of a press machine through the combined action of the male die, the female die and the blank holder, the blank holder of the embodiment is a clamping force provided by the blank holder in the drawing forming process, the clamping force can enable the blank holder to be matched with the female die to clamp the sheet material, the forming force of the embodiment is the sum of the reaction force of the matched clamping force and the force required by various forms on a formed part, the blank holder stroke of the embodiment is the lifting height of the blank holder relative to the male die, the blank holder stroke enables the female die to be matched with the blank holder to clamp the sheet material before the sheet material contacts with the male die, and the blank holder stroke can also play a role in avoiding the effect that the sheet material is wrinkled due to the contact with the male die in advance.
The 3D digital model of the part in step S11 is a three-dimensional digital model of the target part (the part obtained after the drawing forming process is performed), and the 3D digital model of the part is a model designed in advance, specifically, the 3D digital model of the part in this embodiment may be a model designed according to parameters of the target part (for example, the material and the size of the target part), and it should be understood that the 3D digital model of the part in this embodiment corresponds to an equal-ratio model of the target part. The part boundary contour in step S11 is a contour of a boundary of the 3D digital model of the part, the part boundary contour corresponds to an outer contour of the 3D digital model of the part, step S11 may acquire the part boundary contour according to the 3D digital model of the part by using existing design software (for example CAD, thinkDesign or SolidWork), and step S11 may acquire the part boundary contour by performing contour extraction on the 3D digital model of the part by using an existing contour extraction algorithm or a contour extraction model. The minimum envelope size information in step S11 is the size of the minimum envelope corresponding to the 3D digital-analog of the part, and in step S11, the minimum envelope corresponding to the 3D digital-analog of the part may be generated by using the existing envelope generating software (e.g., CATIA), the envelope generating model, or the envelope generating method, and then the size of the minimum envelope is measured by using the existing size measuring model or the size measuring algorithm, so as to obtain the minimum envelope size information.
The length information of the drawing parting line in the step S12 is the total length of the drawing parting line, and the drawing parting line is the boundary between the blank holder and the male die. The specific process of obtaining the length information of the drawing parting line in step S12 may be: a1, determining the position of a trimming line according to the boundary contour of a part by using the existing trimming line determining method; a2, primarily estimating the position of a drawing parting line; a3, sequentially performing drawing, cone drawing and punch rounding on the drawing parting line; a4, if the distance from the tangent point of the horizontal tangent line of the convex die fillet to the trimming line exceeds a preset range, the position of the drawing parting line needs to be readjusted, and the step A3 is returned, and if the distance from the tangent point of the horizontal tangent line of the convex die fillet to the trimming line is within the preset range, the step A5 is executed; a5, taking the drawing parting line at the moment as a final drawing parting line, and acquiring length information of the drawing parting line based on the drawing parting line.
The drawing parting line of the embodiment can feed back the size of the target part, and as the larger the target part is, the larger the plate material required by the drawing forming process is, the larger the acting force required for clamping the plate material is, namely, the drawing parting line length information of the embodiment is positively correlated with the blank holder force, so that the step S13 can calculate the blank holder force based on the drawing parting line length information. The first conversion relationship in step S13 may be a preset linear regression equation or a preset drawing parting line length and blank holder force mapping table, and the first conversion relationship may convert drawing parting line length information into blank holder force, so that step S13 may obtain blank size according to the drawing parting line length information and the first conversion relationship. Since the blank holder force is the clamping force provided by the blank holder, and the forming force is the sum of the reaction force matched with the clamping force and the force required for various forms on the formed part, the greater the clamping force, the greater the forming force, i.e. the blank holder force of this embodiment is positively correlated with the forming force, the step S14 can calculate the forming force based on the blank holder force. The second conversion relationship in step S14 may be a preset linear regression equation or a preset blank holder force and forming force mapping table, where the second conversion relationship can convert the blank holder force into the forming force, so step S14 may obtain the forming force according to the blank holder force and the second conversion relationship. In this embodiment, the bead stroke is the lifting height of the bead relative to the punch, the higher the target part is, the greater the bead stroke is, and since the 3D digital model of the part is an equal proportion model of the target part and the minimum envelope size information is the size of the minimum envelope corresponding to the 3D digital model of the part, that is, the minimum envelope size information can reflect the height of the target part, the minimum envelope size information of this example is positively correlated with the bead stroke, and step S15 can calculate the bead stroke based on the minimum envelope size information and the bead stroke. The third conversion relationship in step S15 may be a preset linear regression equation or a preset mapping table of the size of the envelope body and the stroke of the blank holder, and the third conversion relationship may convert the minimum size information of the envelope body into the stroke of the blank holder, so step S15 may obtain the stroke of the blank holder according to the minimum size information of the envelope body and the third conversion relationship.
According to the drawing molding parameter obtaining method provided by the application, the drawing parting line length information and the minimum envelope body size information are obtained according to the 3D digital-analog of the part, the blank holder force is obtained according to the drawing parting line length information and the first conversion relation, the blank holder stroke is obtained according to the minimum envelope body size information and the third conversion relation, and the molding force is obtained according to the blank holder force and the second conversion relation. In addition, the drawing forming parameters can be obtained by simulating the existing blank holder force, forming force and blank holder stroke by using simulation software, and the drawing forming parameters can be obtained without simulating by using the simulation software, so that compared with the prior art, the application can abandon the limitation of the simulation software.
In some embodiments, the first conversion relationship includes a binder force calculation formula, as shown in formula (1):
（1）；
Where F Pressing denotes a blank holder force (the unit of blank holder force in the embodiment is ton), α denotes a blank holder force coefficient, R m denotes a tensile strength (the unit of tensile strength in the embodiment is MPa), δ denotes a thickness of a target part corresponding to a 3D digital-analog of the part (the unit of thickness of the target part in the embodiment is mm), and L Dividing into denotes drawing parting line length information (the unit of drawing parting line length information in the embodiment is mm). Since the 3D digital model of the part is an equal proportion model of the target part, the 3D digital model of the part is designed in advance, and the tensile strength of the target part needs to be considered when the 3D digital model of the part is designed, the thickness and the tensile strength of the 3D digital model of the part are preset values, α in this embodiment is obtained from a part blank holder data set collected in advance, the part blank holder data set stores a plurality of part parameter information and a plurality of blank holder forces, the part parameter information and the blank holder forces in the part blank holder data set may be part parameter information and blank holder force corresponding to the designed target part or verified part parameter information and blank holder force, each part parameter information corresponds to one blank holder force, the part parameter information includes the thickness and the tensile strength of the 3D digital model of the part, the more the part blank holder data set contains, and the higher the accuracy of α is. It should be understood that after obtaining the blank holder force, the embodiment may also bind the blank holder force and the part parameter information corresponding to the 3D digital-analog of the part, and store the binding force information in the part blank holder force data set to iteratively update α.
In some embodiments, the second conversion relationship includes a molding force calculation formula, the molding force calculation formula being shown in formula (2):
（2）；
Wherein F Finished products represents a forming force, β represents a forming force coefficient, and F Pressing represents a blank holder force. The binding force of this embodiment is calculated by formula (1), and β of this embodiment is obtained from a pre-collected binding force forming force data set, where a plurality of binding forces and a plurality of forming forces are stored, and the binding force and forming force in the binding force forming force data set may be the binding force and forming force corresponding to the designed target part or the verified binding force and forming force, each binding force corresponds to one forming force, and the more the binding force forming force data set contains, the higher the accuracy of β. It should be appreciated that this embodiment may also bind the binding force and the forming force after the forming force is acquired and store in the binding force forming force dataset to iteratively update beta.
In some embodiments, the minimum envelope volume size information includes an envelope volume height, and the third conversion relationship includes a bead stroke calculation formula, the bead stroke calculation formula being shown in formula (3):
（3）；
Wherein S Edge pressing ring represents a bead stroke, γ represents a bead stroke coefficient, and H Bag(s) represents an envelope height. The gamma of this embodiment is derived from a pre-collected envelope body bead stroke dataset storing a plurality of bead strokes and a plurality of envelope heights, which may be bead strokes and envelope heights corresponding to the designed target part or verified bead strokes and envelope heights, each bead stroke corresponding to an envelope height, the more data the envelope body bead stroke dataset contains, the higher the accuracy of gamma. It should be appreciated that after the bead stroke is acquired, this embodiment may also bind the envelope height to the bead stroke and store it in the envelope bead stroke dataset for iterative updating of γ.
In some embodiments, step S11 includes:
s111, acquiring part boundary contour, minimum envelope size information and part type information according to a part 3D digital model;
the step S13 includes:
s131, acquiring a corresponding first conversion relation according to the part type information;
s132, obtaining a blank holder force according to the length information of the drawing parting line and the first conversion relation;
Step S14 includes:
S141, acquiring a corresponding second conversion relation according to the part type information;
S142, obtaining forming force according to the blank holder force and the second conversion relation;
Step S15 includes:
S151, acquiring a corresponding third conversion relation according to the part type information;
s152, acquiring the stroke of the blank holder according to the minimum envelope body size information and the third conversion relation.
The part type information in step S111 is the type of the 3D part model, the step S111 may acquire the part type information by using the existing part type recognition model to perform part type recognition on the 3D part model, or the step S111 may acquire the part type information by comparing the 3D part model with a model in a pre-built part model database, where models corresponding to different types of parts are stored. Because the same type of parts have the same design rule, and different types of parts have different design rules, namely, different types of parts correspond to different first conversion relations, second conversion relations and third conversion relations, the embodiment is equivalent to obtaining drawing forming parameters by utilizing the first conversion relations, the second conversion relations and the third conversion relations corresponding to the types of 3D digital-analog parts, and therefore obtaining accuracy of the drawing forming parameters is further improved. It should be understood that the first, second and third relationships for different types of parts differ by a, β and γ.
In some embodiments, step S131 includes:
S1311, acquiring a corresponding first conversion relation from a pre-constructed first conversion relation database or a first conversion relation mapping table according to part type information;
Step S141 includes:
S1411, acquiring a corresponding second conversion relation from a second conversion relation database or a second conversion relation mapping table which is built in advance according to part type information;
step S151 includes:
S1511, acquiring a corresponding third conversion relation from a third conversion relation database or a third conversion relation mapping table which is constructed in advance according to the part type information.
The first conversion relation database, the first conversion relation mapping table, the second conversion relation database, the second conversion relation mapping table, the third conversion relation database and the third conversion relation mapping table of the embodiment are all pre-constructed, so that the embodiment can acquire the corresponding first conversion relation from the first conversion relation database or the first conversion relation mapping table, acquire the corresponding second conversion relation from the second conversion relation database or the second conversion relation mapping table and acquire the corresponding third conversion relation from the third conversion relation database or the third conversion relation mapping table in a data extraction mode.
In some embodiments, the step of obtaining minimum envelope volume size information from the 3D digital-to-analog of the part comprises:
Acquiring a minimum envelope corresponding to the 3D digital-analog of the part based on a direction bounding box generation method;
Minimum envelope volume size information is obtained based on the minimum envelope volume.
The method for generating the direction bounding box can generate a rectangular enveloping body with the minimum volume along the extending direction of the target object, so that the obtained minimum enveloping body can be attached to the 3D digital model of the part, the size information of the minimum enveloping body can accurately reflect the size of the 3D digital model of the part, and the obtaining accuracy of the blank holder stroke is effectively improved.
In some embodiments, step S12 includes:
S121, projecting the boundary profile of the part based on a preset coordinate system, and performing offset processing on the projected boundary profile of the part to obtain an offset curve;
s122, simplifying the bias curve to obtain a simplified curve;
s123, projecting the simplified curve to a material pressing surface of the 3D digital model of the part to obtain a drawing parting line;
s124, drawing parting line length information is obtained based on the drawing parting line.
The specific workflow of step S121 may be: dispersing the boundary contour of the part based on a curve dispersing algorithm to obtain a plurality of boundary dispersing points; projecting the boundary discrete points to an XY plane of a preset coordinate system to obtain boundary projection points; biasing the boundary projection points based on a rounding algorithm to obtain bias points; and interpolating the offset points to obtain an offset curve. The specific workflow of step S122 may be: segmenting the bias curve according to the curvature of the bias curve; acquiring a line segment interval when the curvature change value between two segmentation points in the bias curve is smaller than a curvature threshold value; detecting whether adjacent end point extension lines of two adjacent line segment sections are intersected, if so, connecting the two adjacent line segment sections through the end point extension lines, and if not, connecting the end points of the two adjacent line segment sections through straight lines so as to preliminarily simplify the offset curve; optionally, three consecutive bias points in the initially simplified bias curve are regarded as a first point group; when the distance value from the middle offset point of the first point group to the perpendicular line segment of the first line segment (the distance from the middle offset point of the first point group to the perpendicular line segment of the first line segment) is smaller than the preset distance value, the next offset point adjacent to the tail offset point in the first point group and the head offset point in the first point group are regarded as a second point group; and calculating the distance value of the vertical line segment of the second line segment constructed by the two middle offset points in the second point group to the head offset points and the tail offset points of the second point group respectively, removing the middle offset point in the second point group corresponding to one vertical line segment distance value when detecting that the distance value of one vertical line segment is larger than or equal to a preset distance value, regarding the middle offset point in the second point group corresponding to the other vertical line segment distance value as a new head offset point, sequentially selecting three consecutive offset points containing the new head offset point until all the offset points of the offset curve are completely selected and calculated, and obtaining a simplified curve. Step S124 may utilize an existing sizing model or sizing algorithm to size the drawing parting line to obtain drawing parting line length information. It should be understood that step S12 preferably further includes the step of executing between step S122 and step S123: s125, chamfering the sharp corner part of the simplified curve.
According to the drawing forming parameter obtaining method, drawing parting line length information and minimum envelope body size information are obtained according to 3D digital models of parts, edge pressing force is obtained according to the drawing parting line length information and a first conversion relation, edge pressing ring travel is obtained according to the minimum envelope body size information and a third conversion relation, and forming force is obtained according to the edge pressing force and a second conversion relation.
Because only after the blank holder force, the forming force and the blank holder stroke are obtained, the target machine tool can be determined, and the blank holder force, the forming force and the blank holder stroke are required to be obtained in a mode that a designer repeatedly adjusts parameters of simulation software according to part simulation effects in the prior art, the problem that the confirmation efficiency of the target machine tool is low still exists in the prior art.
In a second aspect, as shown in fig. 2, the present application also provides a machine tool determining method, which includes the steps of:
s21, acquiring part boundary contour and minimum envelope size information according to a part 3D digital model;
S22, drawing parting line length information is obtained according to the boundary contour of the part;
s23, obtaining a blank holder force according to the length information of the drawing parting line and the first conversion relation;
S24, obtaining forming force according to the blank holder force and the second conversion relation;
s25, acquiring a blank holder stroke according to the minimum envelope body size information and a third conversion relation;
s26, determining a target machine tool according to the blank holder force, the forming force, the blank holder stroke and preset production conditions, wherein the target machine tool is a machine tool with the blank holder force, the forming force and the blank holder stroke meeting the preset production conditions.
Step S21 to step S25 of this embodiment are the same as step S11 to step S15 of the above-described embodiment, and will not be discussed in detail here. Step S26 corresponds to screening a target machine tool from a plurality of machine tools according to the blank holder force, the forming force, the blank holder stroke and the preset production conditions, wherein the target machine tool is a machine tool with the blank holder force, the forming force and the blank holder stroke meeting the preset production conditions, and the target machine tool is applied to a production line.
In some embodiments, the preset production conditions are: the blank holder force is smaller than the maximum supply tonnage of the machine tool air ejector rod, the ratio of the forming force to the stamping tonnage of the machine tool is smaller than the preset ratio, and the stroke of the blank holder is smaller than the maximum extension length of the machine tool air ejector rod. The maximum supply tonnage of the machine tool air ejector rod, the stamping tonnage of the machine tool and the maximum extension length of the machine tool air ejector rod are all test calibration values of the machine tool when the machine tool leaves a factory. The preset ratio of this embodiment is preferably 0.8, and the size of the preset ratio can be changed according to actual needs by those skilled in the art.
According to the machine tool determining method, drawing parting line length information and minimum envelope body size information are firstly obtained according to 3D digital-analog of a part, then edge pressing force is obtained according to the drawing parting line length information and the first conversion relation, edge pressing ring travel is obtained according to the minimum envelope body size information and the third conversion relation, finally forming force is obtained according to the edge pressing force and the second conversion relation, and a target machine tool is determined according to the edge pressing force, the forming force, the edge pressing ring travel and preset production conditions.
According to the drawing forming parameter obtaining method and the machine tool determining method, drawing parting line length information and minimum envelope size information are obtained according to 3D digital models of parts, edge pressing force is obtained according to the drawing parting line length information and the first conversion relation, edge pressing ring travel is obtained according to the minimum envelope size information and the third conversion relation, and forming force is obtained according to the edge pressing force and the second conversion relation.
In the embodiments provided herein, it should be understood that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (5)
1. The drawing forming parameter acquisition method is applied to a drawing forming process, and comprises the following steps of:
Acquiring part boundary contour and minimum envelope size information according to a part 3D digital model;
acquiring drawing parting line length information according to the part boundary profile;
acquiring the blank holder force according to the length information of the drawing parting line and a first conversion relation;
Acquiring the forming force according to the blank holder force and the second conversion relation;
Acquiring the edge pressing ring travel according to the minimum envelope body size information and a third conversion relation;
The first conversion relation comprises a blank holder force calculation formula, wherein the blank holder force calculation formula is as follows:
；
Wherein F Pressing represents the blank holder force, alpha represents the blank holder force coefficient, R m represents the tensile strength, delta represents the thickness of a target part corresponding to the 3D digital-analog of the part, and L Dividing into represents the drawing parting line length information;
The second conversion relation comprises a forming force calculation formula, wherein the forming force calculation formula is as follows:
；
wherein F Finished products represents a forming force, beta represents a forming force coefficient, and F Pressing represents a blank holder force;
The minimum envelope size information comprises an envelope height, the third conversion relation comprises a blank holder stroke calculation formula, and the blank holder stroke calculation formula is as follows:
；
Wherein S Edge pressing ring represents a bead stroke, γ represents a bead stroke coefficient, and H Bag(s) represents an envelope height;
The step of obtaining the part boundary contour and the minimum envelope size information according to the 3D digital model of the part comprises the following steps:
acquiring part boundary contour, minimum envelope size information and part type information according to a 3D digital model of the part;
the step of obtaining the blank holder force according to the drawing parting line length information and the first conversion relation comprises the following steps:
acquiring a corresponding first conversion relation according to the part type information;
Acquiring the blank holder force according to the length information of the drawing parting line and the first conversion relation;
The step of obtaining the forming force according to the blank holder force and the second conversion relation comprises the following steps:
acquiring a corresponding second conversion relation according to the part type information;
Acquiring the forming force according to the blank holder force and the second conversion relation;
The step of obtaining the blank holder travel according to the minimum envelope size information and the third conversion relation includes:
acquiring a corresponding third conversion relation according to the part type information;
acquiring the blank holder travel according to the minimum envelope size information and the third conversion relation;
the step of obtaining the minimum envelope size information according to the 3D digital-analog of the part comprises the following steps:
Acquiring a minimum envelope corresponding to the 3D digital-analog of the part based on a direction bounding box generation method;
And acquiring minimum envelope size information based on the minimum envelope.
2. The drawing forming parameter obtaining method according to claim 1, wherein the step of obtaining the corresponding first conversion relation according to the part type information includes:
Acquiring a corresponding first conversion relation from a pre-constructed first conversion relation database or a first conversion relation mapping table according to the part type information;
The step of obtaining the corresponding second conversion relation according to the part type information comprises the following steps:
acquiring a corresponding second conversion relation from a second conversion relation database or a second conversion relation mapping table which is built in advance according to the part type information;
the step of obtaining the corresponding third conversion relation according to the part type information comprises the following steps:
and acquiring a corresponding third conversion relation from a third conversion relation database or a third conversion relation mapping table which is constructed in advance according to the part type information.
3. The drawing forming parameter acquiring method according to claim 1, wherein the step of acquiring drawing parting line length information from the part boundary profile comprises:
projecting the boundary contour of the part based on a preset coordinate system, and performing offset processing on the projected boundary contour of the part to obtain an offset curve;
simplifying the bias curve to obtain a simplified curve;
projecting the simplified curve to a material pressing surface of the 3D digital model of the part to obtain a drawing parting line;
And acquiring drawing parting line length information based on the drawing parting line.
4. The machine tool determining method is applied to a drawing forming process, and drawing forming parameters comprise a blank holder force, a forming force and a blank holder stroke, and is characterized by comprising the following steps:
Acquiring part boundary contour and minimum envelope size information according to a part 3D digital model;
acquiring drawing parting line length information according to the part boundary profile;
acquiring the blank holder force according to the length information of the drawing parting line and a first conversion relation;
Acquiring the forming force according to the blank holder force and the second conversion relation;
acquiring the edge pressing ring travel according to the minimum envelope body size information and a third conversion relation;
Determining a target machine tool according to the blank holder force, the forming force, the blank holder stroke and preset production conditions, wherein the target machine tool is a machine tool with the blank holder force, the forming force and the blank holder stroke meeting preset production conditions;
The first conversion relation comprises a blank holder force calculation formula, wherein the blank holder force calculation formula is as follows:
；
Wherein F Pressing represents the blank holder force, alpha represents the blank holder force coefficient, R m represents the tensile strength, delta represents the thickness of a target part corresponding to the 3D digital-analog of the part, and L Dividing into represents the drawing parting line length information;
The second conversion relation comprises a forming force calculation formula, wherein the forming force calculation formula is as follows:
；
wherein F Finished products represents a forming force, beta represents a forming force coefficient, and F Pressing represents a blank holder force;
The minimum envelope size information comprises an envelope height, the third conversion relation comprises a blank holder stroke calculation formula, and the blank holder stroke calculation formula is as follows:
；
Wherein S Edge pressing ring represents a bead stroke, γ represents a bead stroke coefficient, and H Bag(s) represents an envelope height;
The step of obtaining the part boundary contour and the minimum envelope size information according to the 3D digital model of the part comprises the following steps:
acquiring part boundary contour, minimum envelope size information and part type information according to a 3D digital model of the part;
the step of obtaining the blank holder force according to the drawing parting line length information and the first conversion relation comprises the following steps:
acquiring a corresponding first conversion relation according to the part type information;
Acquiring the blank holder force according to the length information of the drawing parting line and the first conversion relation;
The step of obtaining the forming force according to the blank holder force and the second conversion relation comprises the following steps:
acquiring a corresponding second conversion relation according to the part type information;
Acquiring the forming force according to the blank holder force and the second conversion relation;
The step of obtaining the blank holder travel according to the minimum envelope size information and the third conversion relation includes:
acquiring a corresponding third conversion relation according to the part type information;
acquiring the blank holder travel according to the minimum envelope size information and the third conversion relation;
the step of obtaining the minimum envelope size information according to the 3D digital-analog of the part comprises the following steps:
Acquiring a minimum envelope corresponding to the 3D digital-analog of the part based on a direction bounding box generation method;
And acquiring minimum envelope size information based on the minimum envelope.
5. The machine tool determination method according to claim 4, wherein the preset production conditions are: the blank holder stroke is smaller than the maximum extension length of the machine tool air ejector rod.
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