KR20110076569A - Deep drawing mold and method of press molding by using the same - Google Patents

Abstract

PURPOSE: A deep drawing mold and a press forming method using the same are provided to enhance drawing limit by reducing flange inflow resistance to drawing deformation through repetitive removing of flow resistance recognized by a material. CONSTITUTION: A die(20) is installed at a upper mold(10). A punch(40) is installed on a lower mold(30) to face the die. A blank holder(50) is installed over the lower mold and constrains a material. A driving unit is installed at the lower mold, is connected to the blank holder and regularly increases/decreases pressure of the blank holder applied to the material. The driving unit regularly increases/decreases pressure applied to the blank holder depending on moving stroke or moving time of the die. The driving unit comprises a driving cylinder, which is stretched by air or fluid pressure.

Description

DEEP DRAWING MOLD AND METHOD OF PRESS MOLDING BY USING THE SAME}

The present invention relates to a deep drawing mold and a press molding method using the same. More particularly, the present invention relates to a deep drawing mold used for forming a sheet and a press molding method using the same.

Magnesium alloy has excellent machinability, high vibration damping ability, excellent absorbency against vibration and shock, excellent electromagnetic shielding properties, light weight, high specific strength, and can be formed into a thin plate in terms of processing.

Therefore, in recent years, the demand is expanding widely in the technical field which requires not only the case parts of a computer, a camera, a mobile phone, but also a traditional metal plate, such as an automobile.

In order to form a magnesium sheet, warm forming such as deep drawing is essential at a temperature of about 250 ° C or higher. However, in spite of the molding such as deep drawing, the magnesium sheet has a lower molding limit than other deep metal materials.

As described above, the matters described in the "Background art" are intended to help the understanding of the background of the present invention, and the technology described in this part is not necessarily the prior art, and is not known in the art, such as the technology falling within the protection scope of the present invention. Can be.

The present invention provides a deep drawing mold and a press molding method using the same, by which the drawing limit of magnesium plate can be improved to improve the molding quality and can be molded effectively.

To this end, the deep drawing mold includes a die installed on an upper die, a punch installed on a lower die opposite to the die, a blank holder installed on the lower die and restraining a material between the die, and the blank holder installed on the lower die. It may be connected to the driving portion for periodically increasing or decreasing the material pressing force of the blank holder.

The driving unit may have a structure for increasing or decreasing the pressure applied to the blank holder periodically according to the movement stroke or the movement time of the die.

The driving unit may include a driving cylinder that is stretched by air or hydraulic pressure.

The plate may be a magnesium plate.

Meanwhile, the press molding method may include fixing a material between the blank holder and the die, performing press molding by applying a physical force to the material, and periodically increasing or decreasing the material pressing force of the blank holder.

As described above, according to the present embodiment, the flow resistance received by the material may be repeatedly solved to reduce the flange inflow resistance to the drawing deformation, thereby improving the drawing limit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

The drawings are schematic and illustrate that they are not drawn to scale. The relative dimensions and ratios of the parts in the figures have been exaggerated or reduced in size for clarity and convenience in the figures and any dimensions are merely exemplary and not limiting. And the same structure, element or part that appears in more than one figure the same reference numerals are used in different embodiments to indicate corresponding or similar features.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular characteristic, region, integer, step, operation, element, and / or component, and other specific characteristics, region, integer, step, operation, element, component, and / or group. It does not exclude the presence or addition of.

Embodiments of the invention described with reference to a perspective view specifically illustrate an ideal embodiment of the invention. As a result, various modifications of the illustrations, for example, manufacturing methods and / or specifications, are expected. Thus, the embodiment is not limited to any particular form of the depicted area, but includes modifications of the form, for example, by manufacture. The regions shown in the figures are only approximate in nature, and their forms are not intended to depict the exact form of the regions and are not intended to narrow the scope of the invention.

1 schematically shows a deep drawing mold according to this embodiment.

In the following description, the deep drawing mold will be described as an example of deep drawing a magnesium sheet as a material. Of course, the deep drawing mold is not limited to the molding of magnesium sheet, it will be applicable to a variety of materials.

As shown, the deep drawing mold includes an upper mold 10 and a lower mold 30 corresponding thereto. The upper die 10 is provided with a die 20, the lower die 30 is installed at a position corresponding to the die 20, and the punch 40 is engaged with the die 20 to form a magnesium plate (P) It is provided. The lower mold 30 has a magnesium plate P placed outside the punch 40 and a blank holder 50 for engaging and fixing the magnesium plate P between the lower end of the die 20 is installed.

Here, the deep drawing mold further includes a driving part installed at the lower mold 30 and connected to the blank holder 50 to periodically increase and decrease the magnesium plate material P pressing force of the blank holder 50.

As a result, the blank holder pressure applied to the magnesium plate P by the blank holder 50 is periodically increased or decreased according to the operation of the driving unit.

In this embodiment, the drive unit is installed in the lower die 30 and the piston rod front end may include a drive cylinder which is connected to the blank holder 50 is operated by air or hydraulic pressure. The driving part is not particularly limited to a structure that can vary the force applied to the blank holder 50.

The drive unit changes the period of the force in accordance with the movement stroke or the movement time of the lower die (30).

That is, as shown in FIG. 2, the driving unit varies the force applied to the blank holder 50 at a predetermined cycle according to the movement time (or movement stroke) of the die 20 of the upper die 10. The blank holder pressure applied to the magnesium plate (P) is repeated to increase and decrease with the cycle.

Therefore, in the process of deep drawing the magnesium plate (P) it is possible to repeatedly eliminate the flow resistance received by the magnesium plate (P) and to reduce the flange inflow resistance to the drawing deformation.

Looking at the press-molding process of the magnesium plate (P) through the device below, the magnesium plate (P) is placed on the blank holder 50 of the lower mold (30).

In this state, when press molding is started on the magnesium sheet P, the lower die 30 is lowered, and the die 20 installed in the lower die 30 moves to the magnesium plate P, whereby the blank holder 50 and the die 20 are moved. The magnesium plate (P) is engaged between the two to fix it.

As the lower die 30 continues to descend while the magnesium plate P is fixed, the blank holder 50 moves downward while engaging and fixing the magnesium plate P between the die 20 and the punch ( 40) exerts a physical force on the magnesium plate (P) to press-press the magnesium plate (P).

Here, as the die 20 of the lower die 30 is gradually lowered, the blank holder 50 is blanked against the magnesium plate P while the punch 40 applies the magnesium plate P to the physical force. The holder pressure is periodically increased or decreased.

That is, the driving unit connected to the blank holder 50 periodically increases or decreases the pressure applied to the blank holder 50 according to the falling stroke or the falling time of the die 20. Therefore, the blank holder 50 periodically increases or decreases the blank holder pressure applied to the magnesium sheet P during the press molding of the magnesium sheet P as described above.

Accordingly, the magnesium sheet material P is repeatedly eliminated from the flow resistance received by the magnesium plate material P in the press molding process, and the flange inflow resistance to the drawing deformation is reduced. Therefore, it is possible to improve the deep drawing limit for the magnesium plate (P).

Table 1 below is a chart comparing the drawing ratio LDR when the blank holder pressure is periodically varied as in the present embodiment and when the blank holder pressure is kept constant according to the prior art.

TABLE 1

Blank Holder Pressure (kN) Max Punch Rod (kN) Drawing ratio 10 (schedule) 52 1.72 5 (schedule) 47 1.81 1 to 10 (5 Hz) 35 1.98 1 to 5 (5 Hz) 30 2.06

 As shown in Table 1, when the blank holder pressure is periodically varied as in the present embodiment, it can be seen that the drawing ratio LDR is improved by about 20% compared with the conventional fixed blank holder pressure.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

1 is a schematic view showing a deep drawing mold according to the present embodiment.

2 is a graph showing the change of the blank holder pressure applied to the material by the blank holder in the deep drawing mold according to the present embodiment.

Explanation of symbols on the main parts of the drawings

10: Pictograph 20: Die

30: lower mold 40: punch

50: blank holder

Claims (7)

Daiwa installed in the upper mold, A punch installed in the lower die and arranged against the die, A blank holder installed on the lower mold and for restraining a material between the die and the die, The driving unit is installed in the lower mold and connected to the blank holder to periodically increase or decrease the blank holder pressure applied to the material Deep drawing mold comprising a. The method of claim 1, And the driving part increases and decreases the pressure applied to the blank holder periodically according to the movement stroke or the movement time of the die. The method according to claim 1 or 2, The driving part deep drawing mold including a drive cylinder that is stretched by air or hydraulic pressure. The method of claim 3, wherein The material is a deep drawing mold is a magnesium plate. Securing the material between the blank holder and the die, Performing press molding by applying physical force to the material, Periodically increasing or decreasing the blank holder pressure applied to the material by the blank holder Press molding method comprising a. The method of claim 5, The step of periodically increasing or decreasing the blank holder pressure is a press forming method of the structure to increase or decrease periodically according to the movement stroke or the movement time of the die. The method of claim 6, The material is a press forming method of magnesium plate material.

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