KR20090063336A - Mold for manufacturing test piece multy-molding test, molding method using the same and method for analyzing test piece - Google Patents

Abstract

A mold for manufacturing a specimen, a molding method of the specimen using the same and an evaluation method of the specimen thereof are provided to obtain the data toward the anisotropy of the specimen based on the date for the evaluation of the forming limit consisting of a composite molding mode. A mold for manufacturing a specimen to evaluate complex formability comprises: a lower mold having two or more deformable units among a drawing deformed unit(310), a planar deformed unit(320) or a biaxial tension deformed unit(330); an upper mold(300) including two or more deformable units among the drawing deformed unit, the planar deformed unit or the biaxial tension deformed unit corresponding to the lower mold; and a pressure unit providing the pressure to mold two or more deformable units among the drawing deformed unit, the planar deformed unit or the biaxial tension deformed unit by pressing a molded member in which the upper mold is located on the lower mold.

Description

MOLD FOR MANUFACTURING TEST PIECE MULTY-MOLDING TEST, MOLDING METHOD USING THE SAME AND METHOD FOR ANALYZING TEST PIECE}

The present invention can reduce the molding process of the specimen, the specimen for manufacturing the mold for the evaluation of the composite moldability to ensure the reliability of the data on the molded specimen, the molding method of the specimen using the same and the evaluation method of the molded specimen thereby It is about.

In general, the molding mode generated during the press working of the sheet material can be divided into three categories: drawing mode, plain strain tension mode, biaxial stretching mode. Conventional formability evaluation methods corresponding to each molding mode generally include evaluation of drawing deformation based on the limit drawing ratio (LDR) by the cup test method, and planar strain rate by the planar deformation elongation test method. Evaluation of planar deformation based on FLCo) and biaxial tensile deformation based on dome height by the limiting dome test method are made.

In order to evaluate the formability of the sheet material by each of the molding modes, the respective sheet materials are formed independently through the respective molding modes (molding method), and thus the molding state for each sheet molded in the respective molding modes. After the evaluation of, the evaluation for each molding mode is integrated to obtain information (data) about the molding limit for the plate.

That is, in order to obtain the information related to the molding limit for one molded material, to determine the overall molding state of the plate for each molding mode, and to measure the molding state according to each of the independent molding modes listed above. Each test method must be performed. In other words, there is a problem that the test method is very cumbersome because each test method for a single material must be performed in an independent state. In addition, for these tests, there is a problem in that each mold suitable for a molding mode such as each drawing deformation, planar deformation, and biaxial tensile deformation must be independently provided.

Moreover, since the deformation applied to the forming of the plate in the actual forming process is rarely made independently, and at least two or more deformations are made in combination, forming the plate by combining the information obtained by the conventional forming modes. Even if the limit data is prepared, the process must be designed by reconsidering the variables generated during the drawing process for the actual sheet material. In addition, since the tests for each independent molding mode have errors for each test by each molding mode, these errors are a factor that makes it difficult to access accurate information during drawing processing for molding in the complex deformation mode. have. For this reason, there is a demand for a method of obtaining data having higher reliability of molding limits.

In addition, the limit drawing ratio LDR and the limit dome height obtained as a result of the above test method are known to have a lot of limitations in order to predict the actual molding limit occurring in the field pressing process. In addition, in order to obtain the data of the molding limit for the sheet for drawing processing, in addition to the test methods listed above, a separate uniaxial tension test was required to perform a hassle.

On the other hand, the dome ejection test method is known as the most common conventional evaluation method that can form a Forming Limit Diagram (FLD). According to this method, there is an advantage in that it is possible to grasp molding limits in various molding modes. However, in order to create one molding limit, it is necessary to have a large number of specimens of different widths. It is a test method.

 The invention is a technology belonging to the test and evaluation of the formability of the plate material, by implementing a variety of molding modes of the plate in a single mold device not only reduces the cost and effort required for the evaluation of the formability, but also a more practical and comprehensive formability evaluation Research is needed to make this possible.

The present invention is made by recognizing at least one of the requirements or problems arising in the test process performed to obtain information on the limit of formability for forming the conventional plate as described above.

One object of the present invention is to be able to obtain the forming limit data of the plate material having a higher reliability for the drawing processing consisting of a complex forming mode.

Another object of the present invention is to allow the drawing process for the preparation of the specimen for the measurement of the molding limit based on the complex molding mode is made through one mold.

Yet another object of the present invention is to allow the molding of a complex molding mode made in one mold to be made as an independent molding mode.

Another object of the present invention is to obtain data on the anisotropy of the specimen based on the data for the evaluation of the molding limit consisting of a complex molding mode.

Another object of the present invention is to allow the processing of the specimen for the evaluation of the molding limit consisting of a complex molding mode to be made of a single standard specimen.

Still another object of the present invention is to make it possible to build the data of the actual molding limit for the plate material processed in a complex molding mode, to facilitate the application of the data constructed in the drawing processing in the field.

Another object of the present invention is to simplify the test method and / or evaluation method for measuring the molding limit of the plate processed in the composite molding mode.

The mold for the evaluation of the composite moldability, the method for forming a specimen using the same, and the method for evaluating the molded specimen formed according to an embodiment for realizing at least one of the above problems may include the following features. .

The present invention is based on being configured to improve the reliability of the data on the molding limit by basically forming the complex molding mode through a single mold.

According to one embodiment of the present invention, a mold for manufacturing a specimen for evaluating composite moldability includes a lower mold including at least two deformation parts of a drawing deformation part, a plane deformation part, and a biaxial tensile deformation part; An upper mold provided with at least two deformation parts of a drawing deformation part, a plane deformation part, and a biaxial tensile deformation part corresponding to the lower mold; The upper mold may be configured to include a pressing portion for pressing the molded member positioned in the lower mold to provide a pressing force so that at least two or more deformation portions of the drawing deformation portion, the plane deformation portion, and the biaxial tensile deformation portion are molded.

In this case, the drawing deformation part may include a wall part and a corner part formed asymmetrically at both ends of the wall surface. On the other hand, the drawing deformation portion may be configured to form a corner portion formed by combining the partial region of the circle, ellipse and straight line on both ends of the wall surface and the wall surface. In addition, the drawing deformation part may be configured to form corner portions formed at both ends of the wall surface portion and the wall surface by combining some regions of circles, ellipses, and straight lines having different dimensions. In addition, the corner portions may be configured to be asymmetric with each other.

In addition, the planar deformation part may be provided with a stepped portion so that the height is formed at the second stage for the plane deformation. On the other hand, the flat deformation portion may be provided with a stepped portion on the side surface portion, and corner portions may be provided on both ends of the wall surface portion.

In addition, the biaxial tension portion may be formed in a shape corresponding to that of another adjacent deformation portion to prevent interference of deformation.

In addition, each deformation part may further include an interference prevention part so that the deformation area of the molded member may be independently deformed by the deformation parts. In this case, the interference prevention part includes a wall interference prevention part which prevents interference between the drawing deformation and the plane deformation; Bottom interference to prevent interference between deformation by the drawing deformation and the deformation of the biaxial tension or between deformation by the plane deformation and the deformation of the biaxial tension or between deformation by the drawing deformation and the plane deformation and deformation of the biaxial tension. It may be configured to include a prevention unit.

The molding method according to another embodiment of the present invention is a method of molding a specimen using a mold in which a molding in a complex molding mode is performed, and the amount of lubricant applied to the specimen so as to adjust the molding limit of the molding to be formed into the specimen is different. Adjusting the amount of biaxial tensile strain; Adjusting the amount of deformation of the drawing by varying the pressing force of the upper mold for pressing the specimen; At least two or more of adjusting the amount of plane deformation by varying the position and number of draw beads formed by the lower mold and the blank holder can be made.

In this case, the adjustment of the molding limit of the molding to be formed into the specimen may be made in the order of adjusting the amount of lubricant applied to the specimen, adjusting the pressing force for pressing the specimen, and adjusting the position and number of draw beads. In addition, the adjustment of the molding limit for the molded object to be formed into the specimen may be made by combining a portion of the drawing deformation portion circle, ellipse and straight line.

In addition, the adjustment of the molding limit for the molded object to be formed into a specimen may be made of a stepped portion is provided so that the height is formed in two stages for the plane deformation of the plane deformation.

In addition, an interference prevention area may be provided between the deformation parts so that independent deformation may be made.

An evaluation method according to another embodiment of the present invention is an evaluation method of a specimen in which a composite molding mode is formed, and by measuring a complex deformation state of at least two or more of drawing deformation, planar deformation, and biaxial tensile deformation of a molded specimen. It may be done.

In this case, the evaluation of the state of the drawing molding of the specimen is based on the blank holder force and the punch stroke diagram obtained by the change of the fixing force of the blank holder and the lower mold to the workpiece and the change of the stroke of the upper mold to the workpiece. It may be done.

Han Hyun, the anisotropy of the workpiece may be further evaluated through the path slope of the strain obtained by each deformation state for the specimen.

As described above, according to the present invention, it is possible to obtain the molding limit data of the plate material having a higher reliability for the drawing processing consisting of a complex molding mode.

In addition, according to the present invention, the drawing process for the preparation of the specimen for the measurement of the molding limit based on the complex molding mode can be made through one mold.

In addition, according to the present invention, the molding of the complex molding mode made in one mold can be made to be an independent molding mode.

In addition, according to the present invention, it is possible to obtain data on the anisotropy of the specimen based on the data for the evaluation of the molding limit consisting of the complex molding mode.

In addition, according to the present invention, the processing of the specimen for the evaluation of the molding limit consisting of a complex molding mode may be made of a specimen of a single standard.

In addition, according to the present invention, it is possible to build the data of the substantial molding limit for the plate material processed in the composite molding mode, it is possible to easily apply the data constructed in the drawing processing in the field.

In addition, according to the present invention, it is possible to simplify the test method and / or evaluation method for measuring the molding limit of the plate material processed in the composite molding mode.

In order to help the understanding of the features of the present invention as described above, with respect to the mold for preparing a specimen for the evaluation of the composite moldability, the method for forming a specimen using the same and the evaluation method of the specimen formed by the same according to the embodiment of the present invention I will explain in detail.

Hereinafter, the described embodiments will be described based on the embodiments best suited for understanding the technical features of the present invention, and the technical features of the present invention are not limited by the described embodiments. It is intended to illustrate that the invention can be implemented as described embodiments. Accordingly, the present invention may be modified in various ways within the technical scope of the present invention through the embodiments described below, and such modified embodiments fall within the technical scope of the present invention. And, hereinafter, in order to help the understanding of the embodiments described, in the reference numerals described in the accompanying drawings, among the components that will have the same function in each embodiment is represented by the same or an extension line number.

Embodiments related to the present invention are based on being configured to improve the reliability of the data on the molding limit by basically forming a complex molding mode through a single mold.

As shown in FIG. 1, the mold 10 for specimen fabrication for evaluating the composite moldability according to an embodiment of the present invention includes a lower mold 100 in which a molded object 500 having a plate structure is placed for drawing processing. And a blank holder 200 which acts to press the mold member 500 positioned at the edge of the lower mold 100 between the lower mold 100, and press-forms the mold member 500 to draw the molding. The upper mold 300 that serves as a punch to be made may be configured to be connected to the pressing unit 400.

The mold 10 may be configured to be arranged in a state in which a variety of deformation modes are combined in at least two or more. That is, it can be configured to be able to perform a complex deformation mode by one mold.

In order to enable the molding of such a complex deformation mode, a configuration according to an embodiment of the lower mold 100 is illustrated in FIGS. 2A and 2B.

The lower mold 100 is a drawing deformation portion 110, the planar deformation portion 120 and the molding member 500 is pressed by the upper mold 300 so that the drawing processing can be performed in a complex deformation mode; At least two or more deformation parts of the biaxial tensile deformation part 130 may be provided.

The drawing deformation unit 110 is an area for realizing a drawing deformation mode for the molded object 500, and the drawing deformation unit 110 is an area of a surface located at one side of the lower mold 100. It may be made to include a corner portion (112, 113) provided in the area of the side surface portion 111 and at least one end of the wall surface portion 111. The drawing deformation part 110 is configured to evaluate a simple drawing formability of the object to be formed 500, is formed to be formed over the entire height of the molding region of the lower mold, the wall surface 111 and the corner portion It may be configured so that various forms of deformation can be made along the (112, 113).

For example, the drawing deformation unit 110 may be configured to have any one of an ellipse, a circle, and a straight line. On the other hand, the drawing deformation unit 110 may be configured such that at least two or more forms of ellipses, circles and straight lines are combined. On the other hand, the drawing deformation unit 110 may be configured such that the shape of the ellipse, circle and straight line are combined together. In this case, the specifications of each of the ellipses and / or circles is configured in the same standard (size), or may be configured to be made of different standards.

As an example of such a configuration, as shown in FIG. 4, the corner portion 112 located at one end region of the wall surface portion 111 has two ellipses at both sides of the circle A and the circle A. FIG. (B, C) may be arranged to form the corner portion 112. In this case, the specifications of the two ellipses (B, C) may be the same or different from each other. In addition, the wall surface 111 may be configured such that the ellipse C and two circles A and D are disposed at both sides of the ellipse C to form the wall surface 111. In this case, the specifications of the two circles (A, D) may be the same or different from each other. In addition, in the corner portion 113 disposed in the region of the other end of the wall surface portion 111, an ellipse (C) and a straight line (E) are arranged on both sides of one circle (D) and the circle (D), respectively. It may be configured to form the corner portion 113.

Meanwhile, the two corner parts 112 and 113 may be formed to have a symmetrical structure or to have an asymmetrical structure.

As such, the drawing deformation unit 110 may be configured to have various shapes of curved and / or straight sections so that the evaluation of formability may be variously made through various drawing deformations of the molded object to be molded.

The planar deformation part 120 is an area for implementing a planar deformation mode for the molded object 500, and the planar deformation part 120 is an area of a surface located on any one side of the lower mold 100. It may be made to include a wall portion 121, a corner portion 122, 123 provided in an area of at least one end of the wall surface portion 121, and the stepped portion 124 is located in the center of the wall surface portion 121 have. The stepped portion 124 may be configured such that the shape of the stepped portion 124 may be variously formed, for example, in the shape of a polygon or a semicircle, such that deformation in accordance with each planar shape is possible.

The planar deformation part 120 may enable the plane deformation mode to be performed by the stepped part 124 configured to have two heights. In this case, since the depth of the stepped portion 124 is formed to be lower than the depth of the upper mold 300 described below, the mold 10 until the upper mold 300 descends to the depth of the stepped portion 124. ) And the molded object 500 do not contact each other. Therefore, the frictional force between the mold 10 and the molded object 500 can be reduced, thereby not restraining the negative strain (e ₂ ), so that the planar deformation mode in the corner portions 122 and 123 is easy. Can be performed.

The biaxial tensile deformation unit 130 is an area for implementing the biaxial tensile deformation mode for the molded object 500, and the biaxial tensile deformation unit 130 may be located on the bottom surface of the lower mold 100. . Here, the biaxial tensile deformation unit 130 may be formed in various shapes so that deformations forming different axes may occur.

Meanwhile, the deformation parts 110, 120, and 130 each have at least one interference so that deformations caused by the deformation modes do not affect each region of the molded material 500 that is deformed from each other. Prevention portions 141, 142, and 151 may be provided.

For example, when the drawing deformation unit 110 and the plane deformation unit 120 are disposed adjacent to each other, the deformation characteristics of the drawing deformation unit 110 and the plane deformation unit 120 with respect to each other are not affected. The wall interference prevention parts 141 and 142 may be provided to maintain a constant strain rate. In this case, the wall interference prevention parts 141 and 142 may be formed of a straight line having an infinite curvature, and the wall interference prevention parts 141 and 142 may have a lower mold (between the drawing deformation part 110 and the plane deformation part 120). 100) can be made of any one wall.

As another example, in the relationship between the drawing deformation unit 110 and the biaxial tensile deformation unit 130, the deformation characteristics of the drawing deformation unit 110 and the biaxial tensile deformation unit 130 do not affect each other. The floor interference prevention part 151 may be provided to maintain a constant strain rate. That is, the bottom interference prevention part 151 may include a negative negative strain (e ₂ ) of the drawing deformation part 110 and a negative value of zero generated in the biaxial tensile deformation part 130. By maintaining a constant substrain between strains, interference between the drawing deformation unit 110 and the biaxial tensile deformation unit 130 may be prevented.

On the other hand, the bottom interference prevention unit 151 increases the friction caused by the contact with the molding material 500 to suppress deformation, thereby deforming and biaxially generated in the drawing deformation unit 110 and the planar deformation unit 120. It may be configured to serve to prevent interference between deformations occurring in the tensile deformation portion 130.

In the meantime, the biaxial tensile deformation unit 130 is an area adjacent to the drawing deformation unit 110 and / or the plane deformation unit 120 is adjacent to the drawing deformation unit 110 and / or the plane deformation unit 120. It may be made in the shape corresponding to the shape of.

That is, as shown in FIG. 2B, the area of the biaxially deformable portion 130 adjacent to the wall surface portion 111 of the drawing deformation portion 110 has a planar structure and the wall surface portion 111 of the drawing deformation portion 110. ) And a region adjacent to the corners 112 and 113 of the drawing deformation unit 110 may be formed in such a manner that the planar structure is recessed.

As such, the shape of the biaxial tensile strain 130 may be formed in a shape corresponding to that of each of the draw strain 110 and / or the plane strain 120, such as the drawing strain 110 and the plane strain 120. ) And biaxial tensile strain 130 to prevent interference. If a sufficient interference area is configured, the shape of the biaxial tensile strain 130 may not be limited by the shape of the drawing strain 110 and / or the planar strain 120.

As shown in Figure 3a and 3b, it may be configured to correspond to the respective deformations (110, 120, 130) of the lower mold 100 to be engaged with the lower mold (100). Therefore, the configuration of the upper mold 300 is the configuration and direction of the lower mold 100 is replaced, the characteristics of all the components are the same. Therefore, the general description of the basic configuration and state will be outlined.

The upper mold 300 has a reversed drawing deformation portion corresponding to the lower mold 100 so that the mold 500 may be pressed against the lower mold 100 so that the drawing processing may be performed in a complex deformation mode. At least two or more deformation parts of the 310, the planar deformation part 320, and the biaxial tensile deformation part 330 may be provided.

The drawing deformation part 310 corresponds to the drawing deformation part 110 of the lower mold 100 and is an area for implementing the drawing deformation mode for the shaped material 500. The drawing deformation part 310 may include a corner part 112 and 113 provided in an area of at least one end portion of the wall surface part 111 and the wall surface part 111, like the lower mold 100 of the lower mold 100. It may be formed in a shape corresponding to the drawing deformation unit 110.

In addition, the planar deformation part 320 is an area for implementing a planar deformation mode for the molded object 500, and the planar deformation part 320 corresponds to the planar deformation part 120 of the lower mold 100. It can be made in the shape of a reversed phase. In this case, the planar deformation part 320 is located at the wall portion 321 and the corner portions 322 and 323 provided in the region of at least one end of the wall portion 321, and the central portion of the wall surface portion 321. It may be made to include the stepped portion 324.

In addition, the biaxial tensile strain 330 is an area for implementing a biaxial tensile strain mode for the molding material 500, the biaxial tensile strain 330 is a biaxial tensile strain of the lower mold 100 It may be formed in an inverted shape corresponding to 130.

Meanwhile, each of the deformation parts 310, 320, and 330 may have at least one interference so that deformations generated by the deformation modes do not affect each region of the molded object 500 that is deformed from each other when deformation is performed by the deformation modes. Prevention parts 341, 342 and 351 may be provided. In this case, the interference prevention parts 341, 342 and 351 may be formed in an inverted shape corresponding to the interference prevention parts 141, 142 and 151 of the lower mold 100.

As shown in FIG. 5, the blank holder 200 provides the molding member 500 with a fixing force (blank holder force) with respect to the lower mold 100, and the upper mold 300 has the blank holder 200. Pressing the molded material 500 through the hole 220 of the molded material 500 is configured to be pushed into the lower mold 100, can be provided to adjust the moldability by the blank holder force. have.

In this case, a draw bead may be configured at any one wall edge portion 121 of the blank holder 200 and the lower mold 100 to provide a fixing force to the molded object 500. The draw beads may be composed of a draw bead groove 101 provided in the lower mold 100 and a draw bead 211 provided in the blank holder 200. When the molded material 500 is pushed by the draw bead to the position where each of the molding parts of the lower mold 100 is formed by the pressure of the upper mold 300, the degree to be pushed by the pressing force (that is, the amount of stroke ) Can be adjusted. The punch stroke due to the blank holder force and the pressing force of the upper mold 300 by the lower mold 100 and the blank holder 200 affects the formability of the mold 500 as described below. do.

According to the above configuration, the method of forming a specimen using a mold for preparing a specimen for composite moldability evaluation may be performed in the following manner.

As a controllability variable for forming the object 500, the amount of lubricant, the strength of the pressing force, and the strength and / or position of the blank holder force may be adjusted. Controlling the amount of lubricant applied to the molded object 500 to be formed into the specimen is to control the degree of biaxial tensile strain. That is, the state of the biaxial tensile strain may be adjusted by adjusting the frictional force generated by the contact between the mold 10 and the molded object 500. On the other hand, adjusting the strength of the pressing force is to control the stroke to be pressed by the upper mold 300, the mold 500, to control the degree of deformation of the drawing. In addition, adjusting the blank holder force to adjust the degree of planar deformation of the molding member 500 pushed into the lower mold 100 by the upper mold 300 by appropriately adjusting the position and the number of draw beads formed. will be.

Appropriate adjustment can be made using each of these adjustment variables to obtain data of the appropriate molding limit for each molding state for the molding material 500 of different materials.

Here, as an example of the molding method based on each control variable, the step of adjusting the amount of biaxial tension deformation is first performed by varying the amount of lubricant applied to the specimen, the pressing force of the upper mold to press the specimen based on this By adjusting the drawing deformation amount to determine the appropriate pressing force, that is, the punch stroke. Thereafter, the step of adjusting the amount of planar deformation may be performed by varying the position and number of draw beads formed by the lower mold and the blank holder, based on the optimum values of the two adjustment variables.

division Blank Holder Force Coefficient of friction Draw beads Drawing variants Ο Ο Χ Plane deformation Ο Ο Ο Biaxial tensile strain Χ Ο Χ

Table 1 is a table showing the effect between the molding mode by the lubricant, blank holder force, variable draw beads. Based on this table, it can be seen that the friction coefficient acts as a variable affecting all deformations. Therefore, the procedure of the most efficient molding limit adjustment method is to first control the biaxial tensile strain by the lubricant. It can then be seen that the blank holder force is a control variable that affects other strains except biaxial tensile strain. Therefore, after the amount of lubricant is adjusted, it can be said that the blank holder force is adjusted. And, it can be seen that the draw bead only affects the plane deformation. Therefore, it can be said that it is efficient to finally control the deformation of the planar deformation by the variable draw beads.

Evaluation method for the specimen molded for the composite moldability evaluation by the method using the mold and the mold can be made as follows. The evaluation may evaluate the specimen by measuring the combined deformation state of at least two or more of drawing deformation, planar deformation, and biaxial tensile deformation of the molded specimen.

In this case, as shown in FIG. 6, the formability of the plate may be evaluated by the blank holder force-punch stroke distance diagram. FIG. 6 is a blank holder force-punch stroke distance diagram, which is a graph showing a punch stroke distance in which a blank (molded material) breaks according to the blank holder force in each forming mode. In this graph, the blank holder force is in units of force (N) and the punch stroke (punch stroke distance) is in units of length (m). Therefore, the energy absorbed by the workpiece (work) can be obtained based on the punch force up to the stroke position. Will be.

That is, since it is possible to know the energy (J) that can be absorbed by the sheet during the press working, compared with the existing limit drawing ratio (LDR) or anisotropic coefficient, it is possible to provide a more practical evaluation method.

[ Test Example  One]

A square blank having a thickness of 0.7 mm and a length of 500 mm on one side was prepared, and then press molding was performed using the mold apparatus of the present invention. Molding limit was adjusted by adjusting the amount of lubricant as in one embodiment of the molding method described above to adjust the biaxial tensile strain, and then by adjusting the blank holder force to adjust the drawing strain. And, finally, by adjusting the position and number of the draw bead was carried out under the conditions to proceed the step of deformation deformation planar sequentially.

As a result of testing nine different plate materials, the forming limit diagrams of the plate materials were shown in FIGS. 7A to 7I. Each molding mode occurred for almost all materials, and the molding limits were well controlled.

After press working by the above method, in accordance with the definition of Fig. 8, the strain path slope with respect to a point of the biaxial tensile part was measured and the correlation with the anisotropy coefficient was investigated. The strain path slope can be obtained by the slope of a straight line connecting the points showing the strain in any part of the molded object.

9 is a graph showing the relationship between the strain path slope and the anisotropy coefficient for the nine materials of FIGS. 7A to 7I, and it can be seen that these relationships are clearly shown linearly. That is, it can be seen that the evaluation of the anisotropy of the molding can be performed using the strain path slope. The reason why the slope is used for the anisotropy evaluation method is that the higher the anisotropy, the more easily the deformation of the drawing is made, but the biaxial tensile deformation is difficult.

The present invention is not limited to the configuration and method according to the embodiment of the mold for manufacturing the specimen for the evaluation of the composite moldability described above, the molding method using the same and the method for evaluating the molded specimen formed thereby, All or part of each of the above-described embodiments may be selectively combined to constitute various modifications.

1 is a partial cross-sectional view schematically showing the configuration of a mold of an example for molding a specimen for evaluation of composite moldability according to an embodiment of the present invention.

Figure 2a is a perspective view of the lower mold shown in FIG.

FIG. 2B is a plan view of the lower mold shown in FIG. 1.

Figure 3a is a perspective view of the upper mold shown in FIG.

3b is a bottom view of the upper mold shown in FIG.

4 is an exemplary conceptual diagram of a configuration of a drawing deformation unit according to an exemplary embodiment of the present invention.

FIG. 5 is an exemplary partial cross-sectional view for explaining a principle in which a mold member is pressed by the blank holder and the lower mold illustrated in FIG. 1.

6 is a graph showing the relationship between the blank holder force and the punch stroke measured according to one test example of the present invention.

7A to 7I are diagrams showing a molding limit diagram obtained through a test on nine different shaped materials.

8 is a graph showing a strain path slope with respect to a point of the biaxial tensile portion of a molded object measured according to an exemplary embodiment of the present invention.

FIG. 9 is a graph illustrating a relationship between a strain path slope and an anisotropy coefficient for each of the shaped materials illustrated in FIGS. 7A to 7I.

* Description of the main parts of the drawings *

10 ... mold 100 ... lower mold

110,310 ... drawing deformation part 120,320 ... plane deformation part

130,330 ... biaxial tensile strain 200 ... blank holder

300 ... upper mold 400 ... pressing part

Claims (17)

A lower mold including at least two deformation parts of a drawing deformation part, a plane deformation part, and a biaxial tensile deformation part; An upper mold provided with at least two deformation parts of a drawing deformation part, a plane deformation part, and a biaxial tensile deformation part corresponding to the lower mold; The upper mold is a composite comprising a pressing portion for providing a pressing force to press the molded member positioned in the lower mold to form at least two or more deformation parts of the drawing deformation portion, planar deformation portion and biaxial tensile deformation portion Specimen manufacturing mold for evaluation of formability. The mold according to claim 1, wherein the drawing deformation part comprises a wall part and a corner part formed asymmetrically at both ends of the wall surface. The mold according to claim 1, wherein the drawing deformation portion is configured to form corner portions formed at both ends of the wall surface portion and the wall surface by combining a partial area of a circle, an ellipse, and a straight line. The method of claim 3, wherein the drawing deformation portion is configured to form a corner portion formed in the wall surface portion and both ends of the wall by combining a partial region of circles, ellipses and straight lines of different dimensions, the corner portion is asymmetric with each other Specimen manufacturing mold for composite moldability evaluation. According to claim 1, wherein the planar deformation part is a test piece manufacturing mold for composite moldability, characterized in that the stepped portion is provided so that the height is formed in two stages for the plane deformation. The mold for manufacturing a specimen for composite moldability evaluation according to claim 5, wherein the planar deformation portion is provided with a stepped portion at a side surface portion, and corner portions are provided at both ends of the wall surface portion. According to claim 1, wherein the biaxial tension portion for forming a specimen for composite moldability evaluation, characterized in that formed in a shape corresponding to the shape of the other adjacent deformable portion to prevent interference of deformation. The mold as claimed in claim 1, wherein the deformation part further includes an interference prevention part to independently deform the deformation area of the member to be formed by the deformation parts. The apparatus of claim 8, wherein the interference prevention part comprises: a wall interference prevention part that prevents interference between drawing deformation and plane deformation; Bottom interference to prevent interference between deformation by the drawing deformation and the deformation of the biaxial tension or between deformation by the plane deformation and the deformation of the biaxial tension or between deformation by the drawing deformation and the plane deformation and deformation of the biaxial tension. Mold for specimen manufacture for the evaluation of complex formability, characterized in that it comprises a prevention unit. The method of forming a specimen using a metal mold according to any one of claims 1 to 9, Adjusting the amount of biaxial tensile strain by varying the amount of lubricant applied to the specimen; Adjusting the amount of deformation of the drawing by varying the pressing force of the upper mold for pressing the specimen; It characterized in that it is made to control the molding limit of the molding to be formed into the specimen, including at least two or more steps of adjusting the amount of planar deformation by varying the position and number of draw beads formed by the lower mold and the blank holder Forming method of the test piece. The method of claim 10, wherein the adjustment of the molding limit of the molding to be formed into the specimen A method of forming a test piece comprising the steps of adjusting the amount of lubricant applied to the test piece, adjusting the pressing force to pressurize the test piece, and adjusting the position and number of the draw beads. The method according to claim 10, wherein the adjustment of the molding limit for the molded object to be formed into the specimen is performed by combining a portion of the drawing deformation part with a circle, an ellipse, and a straight line. The method according to claim 10, wherein the adjustment of the molding limit for the molded object to be formed into the specimen is performed with the stepped portion formed so that the height of the planar deformation portion is formed at two levels for the plane deformation. 11. The method of claim 10, wherein an interference prevention area is provided between the deformation parts so that independent deformation occurs. An evaluation method of a specimen molded by any one of claims 10 to 14, A method for evaluating a specimen by measuring a composite deformation state of at least two of drawing strain, planar strain, and biaxial tensile strain of the molded specimen. 16. The blank holder force and punch of claim 15 wherein the evaluation of the state of the drawing molding of the specimen is achieved by a change in the clamping force of the blank holder and the lower mold relative to the workpiece and a change in the stroke of the upper mold relative to the workpiece. A method for evaluating a specimen, characterized by the stroke of the stroke. 16. The method of claim 15, wherein the anisotropy of the shaped object is further evaluated through the path slope of the strain obtained by each deformation state of the specimen.

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