CN110020487B - Compensation Method for Deflection and Deformation of Binder Ring of Drawing Die - Google Patents

Abstract

The invention relates to the technical field of stamping die manufacturing, in particular to a deflection deformation compensation method for a blank holder of a drawing die. The invention provides a deflection deformation compensation method for a blank holder of a drawing die, which comprises the following steps of analyzing the deflection deformation of the blank holder by adopting a finite element method, selecting a group of reference points at key positions of the blank holder, sequentially calculating the relative deflection deformation of the rest reference points by taking the reference point with the minimum deflection deformation as a benchmark, taking the relative deflection deformation as compensation values of all the reference points, forming a deflection deformation compensation scheme by position information of all the reference points and corresponding compensation values, and realizing the integral deformation treatment of multi-point control on the blank holder by adopting a multi-point control method. According to the method, the deflection deformation of the blank holder is accurately analyzed and accurately compensated, so that the blank holder of the drawing die can obtain uniform die closing gap after finish machining, and the method has obvious effects of reducing the die manufacturing cost and shortening the die manufacturing period.

Description

Compensation Method for Deflection and Deformation of Binder Ring of Drawing Die

technical field

The invention relates to the technical field of stamping die manufacturing, and more specifically relates to a method for compensating deflection deformation of a blank holder of a drawing die.

Background technique

With the upgrading of products and the continuous improvement of production efficiency requirements, the trend of large-scale stamping dies and multiple parts of one die is becoming increasingly obvious. With the increase of the mold width and the increase of the working load, the deflection and deformation of the blank holder of the mold also increase significantly.

For drawing stamping dies, the deflection deformation of the blank holder will lead to uneven clamping gap between the blank holder and the upper die, so that the contact force distribution between the dies cannot realize the design intention, causing parts cracking, wrinkling and other quality question.

In order to solve this problem, it is usually necessary to manually research and match the profile of the blank holder to gradually eliminate the uneven clamping gap. However, relying solely on manual research and matching methods, the workload of research and matching is too large, which not only leads to high labor costs, but also a long debugging cycle. With the intensification of market competition, product updates and upgrades are becoming more and more frequent, and the cost control requirements of enterprises are becoming more and more stringent. The traditional method of manual research and matching can no longer meet the current short-cycle and low-cost requirements for mold development.

In view of the above problems, another way to solve the problem is to superimpose a surface deformation process opposite to the deflection deformation trend on the basis of the processing data of the original blank holder in the mold design stage to offset the deflection deformation.

However, how to accurately and effectively predict the deflection deformation of the blank holder of the drawing die is a difficult problem in the industry. The deflection deformation behavior of blank holder is affected by many complex factors such as mold structure, press structure, part shape, process design and so on. At present, no matter it is analytical reasoning, empirical formula or industry experience, it is impossible to obtain accurate deflection and deformation distribution of blank holder, the compensation effect is not ideal, and the technical bottleneck needs to be broken through.

At this stage, the mold industry mostly relies on personal experience from past projects to predict deflection and deformation, and the accuracy, reliability, and universal applicability of technical means cannot be guaranteed.

Contents of the invention

The object of the present invention is to provide a method for compensating deflection and deformation of the binder ring of a drawing die, so as to solve the problem that the deflection and deformation of the binder ring of the drawing die lead to uneven clamping gaps.

In order to achieve the above object, the present invention provides a method for compensating the deflection and deformation of the blank holder of a drawing die, comprising the following steps:

Step 1. Use the finite element method to analyze the deflection and deformation of the blank holder, model the compensation processing model, and define the modeling parameters. The modeling parameters include geometric modeling, component material performance, element type and grid size Partitioning, analysis steps and solution algorithms, contact relations and boundary conditions;

Step 2. Select a group of reference points at the key positions of the blank holder, and according to the deflection deformation analysis results, take the reference point with the smallest deflection deformation as the benchmark, and calculate the relative deflection deformation of the remaining reference points in turn, as compensation for each reference point The value, the position information of all reference points and the corresponding compensation value constitute the deflection deformation compensation scheme;

Step 3. In the compensation processing model, import the blank holder surface and all reference points that need to be compensated. For each reference point, according to the deflection deformation compensation scheme, generate the corresponding target points, and adopt the multi-point control method The overall deformation processing of multi-point control is realized for the blank holder.

In one embodiment, the compensation process model is created by computer-aided software.

In an embodiment, the modeling of the geometric modeling structure in the first step specifically includes the modeling of the modeling structure of the mold, the press and related stress transfer components.

In one embodiment, the properties of the component materials in the step 1 specifically include that the mold and press components are elastically deformable bodies, and the elastic deformation properties of the component materials are defined by the elastic modulus and Poisson's ratio.

In one embodiment, the component material in the step 1 is cast iron, the elastic modulus is in the range of 105-155 GPa, and the Poisson's ratio is in the range of 0.2-0.3.

In one embodiment, the unit type and grid size division in the step 1 specifically includes that the unit type is Tet solid unit, and the grid size control range is 25-75mm.

In one embodiment, the analysis step and solution algorithm in step 1 specifically include, adopting the static implicit algorithm, setting the analysis step, the initial step size, the maximum incremental step size and the minimum acceptable incremental step size .

In one embodiment, the modeling parameters in step 1 include contact relationships, specifically, different contact relationships are defined according to the relative sliding relationship between the contact surfaces of each component, and for those with relative sliding between the contact surfaces, define Friction force and normal pressure during relative sliding, if there is no relative displacement between the contact surfaces, the contact relationship is simplified as a connection relationship.

In one embodiment, the modeling parameters in step 1 include boundary conditions, specifically including setting according to the stamping process, die structure, and press structure, and ensuring the balance of forces along the stamping direction Z, between X and The Y direction defines corresponding boundary conditions according to the guide elements.

In one embodiment, the selected position of the reference point in the second step is the area of the management surface inside the drawbead of the blank holder and the outer contour of the blank.

In one embodiment, the distance between the reference points in the second step is less than 1000mm, and the number of reference points for a single blank holder is 8-20.

In one embodiment, in the third step, the position of the target point is the position of the reference point plus a corresponding compensation value.

In one embodiment, the compensation deformation processing model in the third step is established by compensation deformation processing computer-aided software, and the target point position is the reference point position plus the corresponding compensation value.

In one embodiment, in the step 3, the multi-point control method is a point-to-point driving method, and the reference point and its corresponding target point form a vector, and all the vectors form a vector set, and the surface deformation is driven by the vector set, Make the compensation surface.

In one embodiment, in the step 3, the multi-point control method is a point-line joint driving method, and a constraint curve is formed by a reference point whose compensation value is zero, and then a reference point whose compensation value is not zero and its The corresponding target points form a vector, and all vectors form a vector set, and the surface deformation is driven by the constraint curve and the vector set to make a compensation surface.

In one embodiment, in the step three, the multi-point control method is a surface-to-surface driving method, and the curved surface to be compensated is projected along the stamping direction to form a projection surface, and the projection surface is driven and deformed by a point-to-point driving method Form the target surface, use the projection surface and the target surface to drive the surface deformation, and make the compensation surface.

A method for compensating the deflection and deformation of the blank holder of the drawing die proposed by the present invention, through accurate analysis of the deflection and deformation of the blank holder and accurate compensation and deformation processing, the blank holder of the drawing die can be processed without manual research after finishing. In the case of matching, a uniform clamping gap can be obtained, which has obvious effects on reducing the cost of mold manufacturing and shortening the mold manufacturing cycle, and can effectively improve the design level of the blank holder surface of the drawing mold.

The present invention specifically has the following beneficial effects:

1) The finite element modeling method and parameter design for the deflection and deformation of the binder ring of the drawing die are proposed to realize the accurate prediction of the deflection deformation of the binder ring. Compared with the current method relying on personal experience, the analysis of the deflection deformation of the binder ring is improved. Accuracy and reliability, and better technical promotion.

2) The multi-point control method (including three driving modes) is used to shape the deflection deformation compensation surface of the blank holder to realize the control of the deformation trend and improve the accuracy of the compensation data.

Description of drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals represent the same features throughout, wherein:

Fig. 1 discloses a model structure diagram according to an embodiment of the present invention;

Fig. 2 discloses a diagram of analysis results of deflection and deformation of the blank holder according to an embodiment of the present invention;

Fig. 3 discloses a compensation scheme for deflection and deformation of the blank holder according to an embodiment of the present invention;

FIG. 4 discloses the analysis of surface deviation before compensation and after compensation according to an embodiment of the present invention.

The meaning of each reference mark in the figure is as follows:

Slide block 101, upper die 102, blank holder 103, table top 104, ejector rod 105, lower air cushion 106.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the invention, not to limit the invention.

A method for compensating the deflection and deformation of the blank holder of the drawing die proposed by the present invention, the specific technical solution is described in detail as follows.

Step 1. Analyze the deflection and deformation of the blank holder.

The technical solution of the present invention adopts the finite element method to realize accurate analysis of the deflection deformation of the blank holder, models the compensation processing model, and defines the modeling parameters. The specific modeling parameter definition method is as follows:

Geometric modeling of structures. Use computer-aided software (CAD software, such as Catia, UG, etc.) to model the compensation processing model. It specifically includes the modeling structure modeling of molds, presses and related stress transfer components. The specific parameters of the modeling of the geometric modeling structure are based on the actual modeling structure, and the non-bearing components are simplified or deleted.

Component material properties. Considering the elastic deformation behavior of various components such as molds and presses, it is defined as an elastic deformation body, and the elastic modulus and Poisson's ratio are used to define the elastic deformation properties of the component materials.

When the component material is cast iron, the preferred elastic modulus selection range: 105-155GPa; Poisson's ratio selection range: 0.2-0.3.

Element type and grid size division. The deflection deformation of the blank holder is a three-dimensional deformation problem, and the solid element type is required.

In order to obtain a better element division effect, the preferred element type is Tet solid element, and the grid size control range is 25-75mm.

Model assembly. Establish a reference point for each component as a basis for assembly of components. In the assembly coordinate system, each component and its reference point are respectively imported, and then the relative positional relationship of each component is determined according to the position of the reference point for assembly.

Analysis step and algorithm definition. The deflection and deformation process of the blank holder is regarded as a quasi-static process, and the solution format adopts the static implicit algorithm to obtain stable and reliable calculation results.

In one embodiment, the entire analysis step is defined as 1s. The initial incremental step is 0.001~0.01s, the largest incremental step is 0.05~0.2s, and the smallest acceptable incremental step is 10 ^-7 ~10 ^-5 s.

Contact definition. All contact surfaces are defined according to their contact characteristics. For the relative displacement between the contact surfaces, it is necessary to define the friction force and normal pressure during relative sliding. For those with almost no relative displacement between contact surfaces, the contact relationship can be simplified and defined as a connection relationship to improve the efficiency of simulation calculations.

Definition of boundary conditions. Refer to the stamping process, mold structure, press structure, etc. for consistent settings. Along the stamping direction (Z direction), it is necessary to ensure the balance of the force. The magnitude of the load force is consistent with the process design value. In the X and Y directions, the model needs to define corresponding boundary constraint conditions according to the guide elements (such as guide plate, guide post, etc.) to balance the lateral force and prevent unreasonable lateral deformation.

Step 2: Formulate a deflection and deformation compensation plan.

Select a reference point at the key position of the blank holder as the basis for the subsequent surface deformation treatment.

According to the analysis results of deflection and deformation, the relative deflection and deformation of the remaining reference points are calculated sequentially based on the reference point with the smallest deflection and deformation, which is used as the compensation value of each reference point. The position information of all reference points and the corresponding compensation values constitute a deflection and deformation compensation scheme.

In order to correctly reflect the deformation trend of the blank holder, priority should be given to the following two types of location selection reference points:

1) The area of the management surface within the drawbead of the blank holder;

2) The outline of the sheet.

The selected reference point spacing should not be too large, it should be less than 1000mm, and the number of reference points for a single blankholder is 8 to 20.

Step 3, making deflection and deformation compensation data.

In the compensation processing model, import the blankholder profile and all reference points that need to be compensated. The compensation treatment model is established by computer-aided software (CAD software). According to the deflection deformation compensation scheme, a target point corresponding to each reference point is generated. The position of the target point is the position of the reference point plus the corresponding compensation value. The compensation formula is:

Among them, (x _r , y _r , z _r ) are the coordinates of the reference point, (x _t , y _t , z _t ) are the coordinates of the target point, and c is the compensation amount.

According to the coordinate positions of the reference point and the target point, the multi-point control method is used to process the overall deformation of the blank holder to ensure that each control point meets the program requirements, deformation trends such as symmetry, eccentricity, gradient, reference point, etc. and simulation analysis results Consistent, and the surface quality meets the smoothing requirements.

Specifically, considering the complexity of the surface modeling and the symmetry of the deformation trend, the multi-point control method uses three different driving methods to make the compensation surface:

Point to point drive. For the case where the surface modeling is relatively simple, the compensation surface can be made directly by point-to-point driving. The reference point and its corresponding target point form a vector, and all the vectors form a vector set, which drives the surface deformation to make a compensation surface.

Dot-line combined drive. For the case where the surface shape is complex but the deformation trend has a certain symmetry, the compensation surface can be made by joint driving of points and lines. Constraint curves are composed of reference points whose compensation amount is zero, and then vectors are formed by reference points whose compensation amount is not zero and their corresponding target points. All vectors form a vector set, and the surface deformation is driven by the constraint curve and vector set to make a compensation surface. . All geometric elements need to meet the symmetry during construction to ensure that the deformed compensation surface strictly obeys the symmetry requirements.

Face-to-face drive. For complex surface modeling and asymmetric deformation trends, the surface-to-surface driving method is used to make compensation surfaces. First, the surface to be compensated is projected along the stamping direction to form a projection surface, that is, a reference surface. Then, the projection surface (reference surface) is deformed by the point-to-point driving method mentioned above to form the target surface. Finally, the reference surface and the target surface are used to drive the deformation of the surface to make the compensation surface.

For the deformed compensation data, surface quality inspection and deviation analysis are required to ensure that the compensation value is correct and the surface quality of the compensation data is good.

The compensation method of the present invention is further described below in conjunction with the specific embodiment of a certain roof mold:

The first step is to analyze the deflection deformation of the blank holder.

CAD software is used to carry out geometric modeling according to the molding structure of the mold and press, including: slider 101, upper mold 102, blank holder 103, table top 104, ejector rod 105, lower air cushion 106 and other components. The specific structure is shown in Figure 1 shown.

The mold and press components are defined as elastically deformable bodies, the elastic modulus is taken as 130GPa, and the Poisson's ratio is 0.25.

The unit type adopts Tet entity unit. The grid size is 25-75mm.

The assembly coordinate system is established based on the center position of the bottom surface of the mold, and the relative positional relationship of each component is defined.

The calculation and solution process adopts the static implicit algorithm.

The whole analysis step is defined as 1s. The initial incremental step size is 0.01s, the maximum incremental step size is 0.1s, and the smallest acceptable incremental step size is 10 ^-7 s.

Different contact relationships are defined between the contact surfaces of each component according to the relative sliding relationship.

The boundary conditions are defined according to the actual process and the structure of the mold and press. Each guiding element defines a corresponding displacement boundary according to its guiding direction.

Fig. 2 discloses a diagram of analysis results of deflection and deformation of the binder ring according to an embodiment of the present invention. As shown in Fig. 2, it is the analysis result of the deflection and deformation of the binder ring, and different shades of gray color represent different values of deflection and deformation.

The second step is to formulate a deflection and deformation compensation plan.

Fig. 3 discloses a compensation scheme for deflection and deformation of the blankholder according to an embodiment of the present invention. As shown in Fig. 3, 8 reference points are selected in the area inside the pipe inside the blankholder as the basis for subsequent surface deformation processing.

According to the analysis results of the deflection deformation of the blank holder in Fig. 2, record the deflection deformation of 8 reference points respectively, as shown in Fig. In Figure 3, the reference points numbered 1, 3, 5, and 7 are taken as the zero position, and the relative deflection and deformation of the remaining reference points are calculated in turn as the compensation value of each reference point.

As shown in Figure 3, the position information of the eight reference points numbered 1 to 8 and the corresponding compensation values constitute the compensation scheme for the deflection deformation of the blank holder of the roof mold.

The third step is to make deflection and deformation compensation data.

In the CAD software, import the blankholder profile and all reference points that need to be compensated. For each reference point, corresponding target points are generated according to the compensation scheme.

Considering that the shape of the curved surface is relatively simple, a point-to-point driving method is directly adopted to drive the blank holder for overall deformation processing.

FIG. 4 reveals the deviation analysis of the surface before compensation and after compensation according to an embodiment of the present invention. As shown in FIG. 4 , different shades of gray represent different deviations, which are the final actual compensations.

In Figure 2 and Figure 4, grayscale colors are used to characterize the corresponding variables (deflection deformation value, deviation). Since these two groups of variables have gradual changes and irregular changes, different grayscale color depths are used to represent variables. It is more conducive to intuitive and accurate understanding.

A method for compensating the deflection and deformation of the blank holder of the drawing die proposed by the present invention, through accurate analysis of the deflection and deformation of the blank holder and accurate compensation and deformation processing, the blank holder of the drawing die is not researched and matched after finishing Obtaining a uniform clamping gap under certain conditions has obvious effects on reducing mold manufacturing costs and shortening the mold manufacturing cycle, and can effectively improve the design level of the blank holder surface of the drawing die.

The present invention specifically has the following beneficial effects:

1) The finite element modeling method and parameter design for the deflection and deformation of the binder ring of the drawing die are proposed to realize the accurate prediction of the deflection deformation of the binder ring. Compared with the current method relying on personal experience, the analysis of the deflection deformation of the binder ring is improved. Accuracy and reliability, and better technical promotion.

2) The multi-point control method (including three driving modes) is used to shape the deflection deformation compensation surface of the blank holder to realize the control of the deformation trend and improve the accuracy of the compensation data.

Although the methods described above are illustrated and described as a series of acts for simplicity of explanation, it is to be understood and appreciated that the methodologies are not limited by the order of the acts, as some acts may occur in a different order according to one or more embodiments And/or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but can be understood by those skilled in the art.

As indicated in this application and claims, the terms "a", "an", "an" and/or "the" do not refer to the singular and may include the plural unless the context clearly indicates an exception. Generally speaking, the terms "comprising" and "comprising" only suggest the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list, and the method or device may also contain other steps or elements.

The above-mentioned embodiments are provided for those who are familiar with the field to implement or use the present invention, and those who are familiar with the art can make various modifications or changes to the above-mentioned embodiments without departing from the inventive idea of the present invention. The scope of protection of the present invention is not limited by the above-mentioned embodiments, but should be the maximum scope consistent with the innovative features mentioned in the claims.

Claims (13)

1. A drawing die blank holder deflection deformation compensation method, is characterized in that, comprises the following steps: Step 1. Use the finite element method to analyze the deflection and deformation of the blank holder, model the compensation processing model, and define the modeling parameters. The modeling parameters include geometric modeling, component material performance, element type and grid size Partitioning, analysis steps and solution algorithms, contact relations and boundary conditions; Step 2. Select a group of reference points at the key positions of the blank holder, and according to the deflection deformation analysis results, take the reference point with the smallest deflection deformation as the benchmark, and calculate the relative deflection deformation of the remaining reference points in turn, as compensation for each reference point The value, the position information of all reference points and the corresponding compensation value constitute the deflection deformation compensation scheme; Step 3. In the compensation processing model, import the blank holder surface and all reference points that need to be compensated. For each reference point, according to the deflection deformation compensation scheme, generate the corresponding target points, and adopt the multi-point control method The overall deformation treatment of multi-point control is realized for the blank holder; Wherein, the analysis step and solution algorithm in the step 1 specifically include, adopting the static implicit algorithm, setting the analysis step, the initial step size, the maximum incremental step size and the minimum acceptable incremental step size; The selected position of the reference point in the step 2 is the area of the management surface inside the drawbead of the blank holder and the outer contour of the blank. 2. The method for compensating deflection and deformation of the blank holder of a drawing die according to claim 1, wherein the compensation processing model is established by computer-aided software. 3. The method for compensating the deflection and deformation of the blank holder of the drawing die according to claim 1, wherein the modeling of the geometric modeling structure in the first step specifically includes the modeling structure of the mold, the press and related stress transfer components modeling. 4. The method for compensating for deflection and deformation of the blankholder ring of a drawing die according to claim 1, wherein the material properties of the components in the step 1, specifically including that the mold and the press components are elastic deformable bodies, are determined by the modulus of elasticity and the poise The loose ratio defines the elastic deformation properties of the component material. 5. The method for compensating for deflection and deformation of the blank holder ring of a drawing die according to claim 4, wherein the component material in the first step is cast iron material, the elastic modulus ranges from 105 to 155 GPa, and the Poisson's ratio ranges 0.2 to 0.3. 6. The method for compensating deflection and deformation of the blank holder of a drawing die according to claim 1, wherein the division of unit type and grid size in said step 1 specifically includes that the unit type is a Tet solid unit, and the grid size is The control range is 25-75mm. 7. The method for compensating deflection and deformation of the blank holder of a drawing die according to claim 1, wherein the modeling parameters in the first step include contact relations, specifically, the contact surfaces of each component are based on relative sliding Relationship defines different contact relationships. For those with relative slip between contact surfaces, define the friction and normal pressure during relative sliding. For those without relative displacement between contact surfaces, simplify the contact relationship to connection relationship. 8. The method for compensating for deflection and deformation of the blankholder ring of a drawing die according to claim 1, wherein the modeling parameters in the first step include boundary conditions, specifically according to the stamping process, die structure, and press structure Make settings to ensure the balance of the force along the Z direction of the stamping direction, and define the corresponding boundary conditions according to the guide elements in the X and Y directions. 9 . The method for compensating deflection and deformation of a binder ring of a drawing die according to claim 1 , wherein the distance between reference points in the second step is less than 1000 mm, and the number of reference points for a single binder ring is 8 to 20. 10 . 10. The method for compensating deflection and deformation of the blank holder of a drawing die according to claim 1, wherein in the third step, the position of the target point is the position of the reference point plus a corresponding compensation value. 11. The method for compensating deflection and deformation of the blank holder of a drawing die according to claim 1, characterized in that, in the third step, the multi-point control method is a point-to-point driving method, and the reference point and its corresponding target The points form a vector, and all the vectors form a vector set, which drives the surface deformation to make a compensation surface. 12. The method for compensating the deflection and deformation of the blank holder of the drawing die according to claim 1, characterized in that, in the step 3, the multi-point control method is a point-line joint driving method, and the reference value of the compensation value is zero The points form the constraint curve, and then the reference point whose compensation value is not zero and its corresponding target point form the vector, and all the vectors form the vector set, and the surface deformation is driven by the constraint curve and the vector set to make the compensation surface. 13. The method for compensating the deflection deformation of the blank holder of the drawing die according to claim 11, characterized in that, in the third step, the multi-point control method is a surface-to-surface driving method, and the curved surface to be compensated is pressed along the The projection surface is formed by directional projection, and the projection surface is driven and deformed by the point-to-point driving method to form the target surface, and the projection surface and the target surface are used to drive the deformation of the curved surface to make the compensation surface.

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