JPH0450985Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a press mold, and particularly to a press mold that can press-form a workpiece made of a highly extensible material such as aluminum.

Conventional technology As a press mold, for example,
As shown in Publication No. 15426, the blank holder is composed of a die as an upper die, a punch as a lower die, and a blank holder arranged around the punch by elastic floating support in the vertical direction by a die tension. There is something. The die and punch are generally made of cast metal from the viewpoint of economy.

Problems that the invention aims to solve When pressing a workpiece such as an iron plate, even if you use a casting die or punch whose shape surface has been nitrided to increase its hardness, the hardness of the iron plate makes it difficult to press the workpiece. A part of the material does not adhere to the die or punch surface. However, when pressing workpieces made of highly extensible materials such as aluminum, the surface roughness of the die and punch surfaces is rough due to the characteristics of the casting, and there are also minute cavities, so the workpiece may The parts tend to adhere to the shaped surfaces of the die and punch. Moreover, if the next workpiece is press-processed while a part of the workpiece remains adhered, a so-called star pattern problem occurs in which the shape of the adhered object is pressed and transferred to the next workpiece. It has been pointed out that if these star marks appear on the outer panel surface when used as a product through post-processing, it looks bad and cannot be used as a product due to its appearance performance. Furthermore, a method has been proposed in which the shaped surface is nitrided to increase the hardness of the mold surface and prevent adhesion. Difficult to prevent.

Means for Solving the Problem A shape surface of at least one of a die as an upper mold and a punch as a lower mold is configured with a shape structure of a separate member, and this shape structure is attached to and detached from the die or the punch. It consists of a base made of forged and polished steel that can be attached freely, and hard plating applied to the surface of this base.

Function Since the base is made of forged steel, even if there are cavities near the surface of the steel material before forging, the cavities can be removed by forging. Moreover, by polishing the forged steel material that makes up the base, the surface roughness of the base can be smoothed out. Since the smooth finished surface of this base is hard plated, the surface of the shaped structure has mirror-like lubricity and the hardness necessary to prevent aluminum material from adhering.

Embodiment As shown in FIGS. 1 and 2, the press mold of this embodiment generally includes a die 1 as an upper die,
It is composed of a punch 2 as a lower die and a blank holder 3, and the shape surface of the die 1 and the shape surface of the punch 2 are composed of shape structures 4 and 5.

Specifically, the die 1 includes an upper holder 6 and a shaped structure 4. The upper holder 6 is made of cast iron such as FC25, and is attached to a slider of a press machine (not shown). Upper holder 6
A recess 7 is formed in the center of the lower surface, and blank faces 8 are formed on both sides of the lower surface, and the continuous portion of the blank face 8 and the recess 7 forms an arcuate corner-shaped surface 9. ing. A projection 10 is provided on the blank face 8. The shaped structure 4 includes a base 11 made of steel such as S50C that is forged into a shape that is internally fitted into the recess 7 and polished to have a smooth surface roughness.
Hard chrome plating 12 as hard plating is applied to the lower surface exposed from the upper holder 6 of 1 to a thickness of about 30 μm without pinholes. After fitting the base 11 into the recess 7 with the hard chrome plating 12 facing downward, the shaped structure 4 is assembled.
From above the upper partition wall 13 of the recess 7, insert the screw 14 into the base 11.
It is removably attached by fastening it to. When attached to the upper holder 6, the lower surface of the hard chrome plating 12 of the shaped structure 4 is closely and smoothly connected to the corner shaped surface 9.

The punch 2 includes a punch body 20 and a shaped structure 5. The punch body 20 is made of cast iron such as FC25, and is attached to the bed of a press machine (not shown). The shaped structure 5 includes a base 21 made of a steel material such as S50C that is forged into a shape corresponding to the corner shaped surface 9 of the upper holder 6 and the shaped structure 4 and polished to have a smooth surface roughness. On the upper surface of the base 21 facing the corner shaped surface 9 and the shaped structure 4, hard chrome plating 22 is applied to a thickness of about 30 μm without pinholes. The shape structure 5 is made of hard chrome plating 2
2 facing upward, insert the base 21 into the punch body 2.
It is removably attached by placing it on the top surface of 0 and fastening it from below with screws 23.

The blank holder 3 is attached to a dictation of a press machine (not shown), is arranged around the punch 2 in an elastic floating manner, and has a blank face 30 corresponding to the blank face 8 of the upper holder 6. ing. A recess 31 is formed in a portion of the blank face 8 that corresponds to the projection 10.

According to the structure of the above embodiment, the slider of the press machine (not shown) stops at the top dead center position, and the die 1 is spaced above the punch 2 as shown in FIG. In a state where the blank face 30 of the holder 3 is stationary substantially flush with the upper surface of the hard chrome plating 22 of the forming structure 5 of the punch 2 due to the supporting action of the dictation, the aluminum plate cut to the required size in the previous process is A workpiece W is placed on the forming structure 5 of the punch 2 and the blank holder 3 from between the die 1, the punch 2, and the blank holder 3.

From the state shown in Fig. 1, by lowering the slider of the press machine toward the bottom dead center, the die 1 moves downward toward the punch 2 and blank holder 3, and the workpiece W is moved as shown in Fig. 2. It is press-molded like this. That is, the protrusion 10 comes into contact with the work W as the die 1 moves. At this time, since the blank holder 3 remains stationary due to the supporting action of a duct (not shown), a part of the work W is bulged out by the protrusion 10 and the recess 31, and the area around the bulge A of the work W is It is held between the blank faces 8 and 30. In response to the subsequent downward movement of the die 1, the blank holder 3 moves downward due to the movement of a die cutting mechanism (not shown) while maintaining the state in which the work W is held between the blank faces 8 and 30, and the part of the work W that is held between the blank faces 8 and 30 is moved downward. The intermediate portion located in between is formed to bulge while receiving pressure from the shape structure 5 of the punch 2, the shape structure 4 of the die 1, and the corner shape surface 9, and the slider of the press machine stops at the bottom dead center position. do. When the slider stops at the bottom dead center position, the workpiece W receives the necessary pressing force from the die 1, punch 2, and blank holder 3.
When the workpiece W is used as a product after the post-processing, the outer plate surface is in contact with the hard chrome plating 12, 22 of the shaped structures 4, 5, which have mirror-like smooth surface texture and hardness. , adhesion to the shaped surface of the die 1 and the shaped surface of the punch 2 is prevented.

After the state shown in FIG. 2, the slider of the press machine rises toward the top dead center position, and the die 1 moves upward, but at this time, the blank holder 3 is moved to the blank faces 8 and 30 by the movement of the die shaft. moves upward while holding the workpiece W, the bulging part B of the workpiece W separates from the shape structure 5 of the punch 2, and the blank face 30 is approximately flush with the upper surface of the hard chrome plating 22 of the shape structure 5 of the punch 2. When the blank holder 3 becomes one, the blank holder 3 comes to rest. As the die 1 continues to move upward, the corner shaped surface 9 of the die 1, the blank faces 8 and 30, the protrusion 10, and the lower surface of the hard chrome plating 12 of the shaped structure 4 are separated from the workpiece W, and the bulge of the workpiece W is removed. The area around A is placed on the blank face 30, the slider of the press machine stops at the top dead center position, the die 1 is at the top dead center position, and the press process 1 is started.
The cycle ends. Then, after the press-formed workpiece W is taken out from between the die 1, punch 2, and blank holder 3, another new workpiece W is taken out from between the die 1, punch 2, and blank holder 3 with the shape of the punch 2. It is placed on the body 5 and the blank holder 3, and the above pressing process is repeated.

According to this embodiment, the base 1 of the shaped structures 4, 5
Since forged steel materials are used as parts 1 and 21, even if there are cavities near the surface of the steel material before forging, the cavities can be removed by forging. Moreover, since the surfaces of the forged steel of the bases 11, 21 are polished, the bases 11, 21
Surface roughness is smoothed out. Hard chrome plating 12, 22 is applied to the smoothly finished surfaces of the bases 11, 21 without pinholes, so that the shape structure forming the shape surface of the die 1 and punch 2 is formed. The surfaces of the shaped structures 4 and 5 have mirror-like lubricity and hardness necessary to prevent adhesion of a workpiece made of a highly extensible material such as aluminum material. 5 becomes easy to manufacture. Moreover, since the shaped structures 4 and 5 are detachably attached to the upper holder 6 and the punch body 20, only the shaped surfaces of the mold can be replaced, which is economical.

Note that the present invention is not limited to the above embodiments, and although not shown in the drawings, for example, the shaped structures 4 and 5 correspond to the outer surface of the work W when it is used as a product after a post-process. May be used only in parts. Furthermore, the workpiece W before press processing
It is also possible to improve the adhesion prevention performance by applying oil to the surface of the (blank material) or the shaped surface of the die 1 or the shaped surface of the punch 2 to form an oil film.
Further, hard chrome plating 12, 22 may be applied to the entire surface of the base portions 11, 21, or a hard plating other than the hard chrome plating 12, 22 may be used.

Effects of the Invention As described above, according to the present invention, the shape surface of at least one of the die as the upper mold and the punch as the lower mold is formed of a shape structure of a separate member. are small parts compared to dies and punches, which are large parts. Since the base of the shaped structure, which is a small part, is made of forged steel, it is possible to remove cavities that exist near the surface of the steel before forging. Moreover,
By polishing the surface of the forged steel base, the surface roughness of the base is smoothed, and the smooth surface of the base is hard plated, so that the shape of the die or punch is smooth. The surface of the shaped structure forming the structure can have mirror-like lubricity and hardness necessary to prevent adhesion of the aluminum material. As a result, even when press-forming a workpiece made of a highly extensible material such as aluminum, it is possible to prevent the workpiece from adhering to the workpiece, and also to prevent star spots caused by adhesion, thereby reducing wastage of the press-formed product. It can be resolved. In addition, since the base of the shaped structure is detachably attached to the die or punch, it is easier to apply hard plating to the base, which is a small part, compared to the die or punch. It also has the advantage of being economical since only the surface can be replaced.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention with the die stopped at the top dead center position, and Fig. 2 shows the same embodiment with the die stopped at the bottom dead center position. FIG. 1... Die, 2... Punch, 4, 5... Shape structure, 11, 21... Base, 12, 22... Hard chrome plating (hard plating).

Claims (1)

[Scope of utility model registration request] A shape surface of at least one of a die serving as an upper mold and a punch serving as a lower mold is configured with a shape structure of a separate member, and this shape structure is detachably attached to the die or punch, and the shape is forged and polished. A press mold comprising a base made of steel and hard plating applied to the surface of the base.