JP2009226441A - Metallic mold and forming method using the metallic mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic mold which can form a product having no defect, and a forming method using the metallic mold. <P>SOLUTION: In the metallic mold 1 for forming the product having a projecting part while generating a plastic flow to a blank 4 by pressurizing the blank 4 with the respective pressurizing surfaces 21, 31 of a punch 2 and a die 3, at least anyone of pressurizing surfaces 31(21) of the punch 2 and the die 3 is provided with a flow-restraining range 31b for restraining the plastic flow of the blank 4 and a projecting part forming range 31a for forming the projecting part; and the flow-restraining range 31b is formed so that the surface friction coefficient is higher than the surface friction coefficient of the projecting part forming range 31a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mold and a molding method using the mold.

  Conventionally, when manufacturing a product having protrusions by forming a material by forging, a mold is used. The mold includes a die on which a material to be forged is placed, and a punch that moves downward toward the die to reduce the material. On the surface of the die, a recess for forming a protrusion of the three-dimensional product is provided.

  When a product is molded from a material using such a mold, the material is placed on a die, and the material is plastically flowed from above by using a punch to form the material by flowing into the recess. is doing.

  However, when forging a product using the above-mentioned mold, it is difficult for sufficient material to flow into the concave portion of the die corresponding to the protrusion of the product, and defects such as defective flow of the material occur in part of the product. There was a problem.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a mold capable of molding a product having no defect and a molding method using the mold.

  The above object of the present invention is to provide a mold for forming a product having a protrusion by generating a plastic flow in the material by pressurizing the material with each pressing surface of the punch and the die, the punch and the die. At least one of the pressure surfaces includes a flow suppression region that suppresses plastic flow of the material and a protrusion formation region in which the protrusion is formed, and the flow suppression region has a surface friction coefficient thereof. Is achieved by a mold formed so as to be higher than the surface friction coefficient of the protrusion forming region.

  In this mold, it is preferable that the flow suppression region is disposed around the protrusion forming region.

  Moreover, it is preferable that the said flow suppression area | region is formed with several uneven | corrugated | grooved part.

  Moreover, it is preferable that the said protrusion formation area | region is formed in the approximate center part of the said pressurization surface.

  Moreover, it is preferable that the surface friction coefficient of the said protrusion formation area | region is 0.01-0.5.

  Another object of the present invention is a molding method for molding a product having a protrusion using the mold described above, wherein the material placed on the pressure surface of the die is added by the pressure surface of the punch. Achieved by a forming method comprising: a flow step of plastically flowing the material by pressing; and a flow suppressing step of suppressing plastic flow of the material by the flow suppressing region having a higher surface friction coefficient than the protrusion forming region. Is done.

  ADVANTAGE OF THE INVENTION According to this invention, the metal mold | die which can shape | mold a product without a defect and the shaping | molding method using this metal mold | die can be provided.

  Hereinafter, the metal mold | die which concerns on this invention is demonstrated with reference to an accompanying drawing. FIG. 1 is a schematic sectional view of a mold 1 according to an embodiment of the present invention. FIG. 2 is a schematic sectional view of a die 3 constituting the mold 1. FIG. 3 is a plan view of the die 3 shown in FIG. FIG. 4 is a perspective view showing a molded body (product) 5 formed by the mold 1 shown in FIG.

  The mold 1 according to the present embodiment is a press or forging mold for forming a product 5 having protrusions (bosses, ribs, etc.) 51 as shown in FIG. As shown in FIG. 1, the punch 2 and the die 3 disposed below the punch 2 are provided. The punch 2 is configured to be movable up and down by a lifting device such as a press machine (not shown), and includes a punch pressurizing surface 21 that presses down the material 4. The punch pressing surface 21 is formed to have a flat shape.

  The die 3 is fixed by a die holder (not shown), and includes a die pressing surface 31 that is disposed to face the punch pressing surface 21 of the punch 2. As shown in FIGS. 2 and 3, the die pressing surface 31 includes a protrusion forming area 31 a where a protrusion 51 (three-dimensional shape portion) in the product 5 is formed, and a flow suppression area 31 b. In addition, the dashed-dotted line S in FIG. 3 is a virtual line which shows the boundary of the protrusion formation area | region 31a and the flow suppression area | region 31b.

  The protrusion forming region 31a is formed at a substantially central portion of the die pressing surface 31, and a plurality of recesses 32 corresponding to the protrusions 51 of the product 5 are formed in the region. The flow suppression region 31b is disposed around the protrusion forming region 31a. The flow suppression region 31b has a function of suppressing plastic flow of the material 4 that occurs when the punch 2 reduces the material 4 placed on the die 3, and the surface friction coefficient thereof is the protrusion formation. It is formed to be higher than the surface friction coefficient of the region 31a. Examples of a method of providing a difference in height between the surface friction coefficients in the flow suppression region 31b and the protrusion formation region 31a include, for example, a method of applying a coating that reduces the surface friction coefficient to the protrusion formation region 31a of the die pressurizing surface 31, and polishing. Mirror finish etc. can be mentioned. Examples of such coatings include CrN (chromium nitride) coating, TiC (titanium carbide) coating, DLC (diamond-like carbon) coating, and the like. In addition, the value of the surface friction coefficient in the protrusion formation region 31a is preferably in the range of 0.01 to 0.5, for example. The value of the surface friction coefficient in the flow suppression region 31b of the die pressing surface 31 is not particularly limited as long as it is higher than the value of the surface friction coefficient in the protrusion forming region 31a. For example, if the value of the surface friction coefficient in the protrusion formation region 31a is in the range of 0.01 to 0.1, the value of the surface friction coefficient in the flow suppression region 31b can be 0.2 or more.

  In addition, a heating element (not shown) such as a sheathed heater is provided inside the punch 2 and the die 3 so that the punch 2 and the die 3 are heated to a predetermined temperature.

  Next, a method for forging the material 4 made of magnesium or a magnesium alloy using the mold 1 according to the present embodiment will be described with reference to FIG.

  First, as shown in FIG. 5A, the material 4 is placed on the substantially central portion of the die pressing surface 31 of the die 3. Here, the material 4 made of magnesium or a magnesium alloy is heated by driving a press machine (not shown) before pressing because, for example, the ductility is improved in the range of 250 ° C. to 400 ° C. and forging is facilitated. The material 4 is sandwiched between the punch 2 and the die 3, and the temperature of the material 4 is raised so as to be in the above temperature range.

  After the temperature of the material 4 rises to a predetermined temperature, a press machine (not shown) is driven, and the material 4 is pressed down by the punch pressure surface 21 as shown in FIG. Due to this reduction, the material 4 flows into the recess 32 formed on the pressing surface 31 of the die 3 while being deformed by plastic flow. After the reduction by the punch pressing surface 21 is completed, the punch 2 is moved away from the die 3 and the product 5 after the forging process is taken out.

  In the mold 1 according to the present embodiment, the pressing surface 31 of the die 3 includes a flow suppression region 31b that suppresses plastic flow of the material 4 and a protrusion formation region 31a in which the protrusion 51 of the product 5 is formed. The surface friction coefficient in the flow suppression region 31b is set to be higher than the surface friction coefficient in the protrusion forming region 31a. With such a configuration, the contact portion with the flow suppression region 31b in the raw material 4 that is deformed by being punched by the punch 2 receives a high frictional resistance, so that the flow is suppressed. On the other hand, the portion of the material 4 in contact with the protrusion formation region 31a receives a lower frictional resistance than the portion of contact with the flow suppression region 31b, so that the fluidity is high. As a result, a sufficient amount of the material 4 flows into the recess 32 in the protrusion formation region 31a, and it is possible to reliably prevent the material 4 from flowing into the protrusion 51 of the product 5 with high accuracy. A three-dimensional product 5 having no defect can be manufactured.

  In order to confirm the above effect, the inventors conducted a forging experiment using the mold 1 shown in FIGS. 1 to 3, and the experimental results will be described below. The protrusion forming region 31a of the die 3 of the mold 1 was subjected to DLC coating so that the surface friction coefficient was 0.1. The flow suppression region 31b is a satin surface without being subjected to DLC coating. In addition, as the material 4 to be forged, a magnesium alloy plate-shaped material having a height of 36 mm, a width of 46 mm, and a thickness of 0.5 mm and a rectangular shape in plan view was used. The experimental results are shown in FIG. FIG. 6A is a photographic image of a cross section of the columnar protrusion 51 in the molded body shown in FIG.

  Further, for comparison, a mold having the same shape as the mold shown in FIGS. 1 to 3, and using the mold having the same surface friction coefficient on the pressing surface of the die over the entire pressing surface, is made of the above magnesium alloy. FIG. 6B shows the result of forging the plate material. FIG. 6B is also a photographic image of a cross section of the columnar protrusion 51 in the molded body shown in FIG. 5 as in FIG. 6A.

  As shown in the photograph of FIG. 6 (a), the projection 51 of the molded body 5 forged by the mold 1 according to the present embodiment is free from inflow of the material 4, and its outer shape It can be seen that the shape is clean. On the other hand, in the photograph of the comparative example shown in FIG. 6B, it can be seen that the material 4 is poorly flowed and the outer shape of the protrusion 51 is irregular.

  Moreover, since the metal mold 1 according to the present embodiment is in a state in which the material 4 is likely to flow at the contact surface between the protrusion forming region 31 a forming the protrusion 51 of the product 5 and the material 4, the protrusion The thickness of the product portion formed by the region sandwiched between the surface where the recess 32 is not formed in the formation region 31a and the punch pressing surface 21 of the punch 2 is, for example, 0.5 mm or less, which is difficult to manufacture by die casting. It can be formed into a thin shape.

  As described above, according to the mold 1 according to the present embodiment, it is possible to integrally form a product having protrusions such as bosses and ribs without defects on a thin plate material with high accuracy.

  In the present embodiment, since the flow suppression region 31b having a surface friction coefficient higher than that of the protrusion formation region 31a is disposed around the protrusion formation region 31a that forms the protrusion 51 of the product 5, the punch The movement of the material 4 that plastically flows due to the reduction of 2 can be suppressed in the entire area around the protrusion forming region 31a. As a result, the material 4 flows more reliably into the recess 32 formed in the protrusion forming region 31a, and the product 5 having high accuracy and no defects can be formed by forging.

  Moreover, in the said embodiment, since the protrusion formation area | region 31a is formed in the approximate center part of the die pressurization surface 31, the raw material 4 is formed in the circumference | surroundings from the protrusion formation area 31a by the pressing of the punch 2. It will flow toward the flow suppression region 31b. Since the plastic flow of the material 4 is suppressed in the flow suppression region 31b, the material 4 can be surely poured into the recess 32 in the protrusion forming region 31a.

  As mentioned above, although one Embodiment of the metal mold | die 1 which concerns on this invention was described, the specific structure of this invention is not limited to the said embodiment. For example, in the said embodiment, although the structure where the pressurization surface 31 of the die | dye 3 is provided with the flow suppression area | region 31b and the protrusion formation area | region 31a is employ | adopted, for example, the pressurization surface 21 of the punch 2 flows. A configuration including the suppression region 31b and the protrusion formation region 31a may be employed. Further, a configuration is adopted in which the pressure surface 31 of the die 3 and the pressure surface 21 of the punch 2 are each provided with a flow suppression region 31b and a protrusion formation region 31a, and a molded body having protrusions 51 on both surfaces is formed. You may comprise as follows.

  Further, as shown in FIG. 7, by forming a plurality of uneven portions 33 in the flow suppression region 31 b of the pressing surface 31 of the die 3, the friction coefficient between the protrusion formation region 31 a and the flow suppression region 31 b is increased or decreased. The difference can be expanded. As a method of forming the uneven portion 33 in the flow suppression region 31b, for example, electric discharge machining, chemical polishing, shot blasting, machining, or the like can be performed on the flow suppression region 31b of the die pressing surface 31. . In this way, by increasing the surface roughness of the flow suppression region 31b, the flow suppression region 31b can more strongly suppress the flow of the material 4 that flows due to the reduction of the punch 2, so that the protrusion A sufficient amount of the material 4 can be reliably poured into the concave portion 32 in the formation region 31a, and it is possible to reliably prevent a defect such as a poor flow of the material 4 from occurring in the protrusion 51 of the product 5.

  Moreover, in the said embodiment, as shown in FIG. 3, the structure which forms the protrusion formation area | region 31a in the approximate center part of the pressurization surface of die | dye 3, and arrange | positions the flow suppression area | region 31b around it is employ | adopted. However, it is not particularly limited to such a configuration. For example, as shown in FIGS. 8A and 8B, a flow suppression region 31b having a high surface friction coefficient is formed in the protrusion forming region 31a. You may comprise. Moreover, as shown in FIG. 3, the boundary S between the protrusion forming region 31a and the flow suppressing region 31b is formed in a rectangular shape, and the shape of the boundary S is, for example, FIG. As shown in (d), various shapes can be adopted. In FIGS. 8A to 8D, the flow suppression region 31b is shown with a color in order to facilitate understanding of the configuration.

It is a schematic structure sectional view of a metallic mold concerning one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a die that constitutes the mold shown in FIG. 1. FIG. 3 is a plan view of the die shown in FIG. 2. It is a perspective view which shows the product forged by the metal mold | die shown in FIG. It is explanatory drawing explaining the method of forging a raw material using the metal mold | die shown in FIG. It is a photograph which shows the experimental result which the inventor performed in order to confirm the effect of the metal mold | die shown in FIG. FIG. 3 is a schematic cross-sectional view showing a modified example of the die shown in FIG. 2. (A)-(d) is a top view which shows the various modifications of the die | dye shown in FIG. 3, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2 Punch 21 Punch pressurization surface 3 Die 31 Die pressurization surface 31a Protrusion formation area 31b Flow suppression area 32 Recess 33 Uneven part 4 Material 5 Product 51 Protrusion

Claims (6)

A mold for forming a product having a protrusion by generating a plastic flow in the material by pressurizing the material with each pressing surface of a punch and a die,
The pressing surface of at least one of the punch and the die includes a flow suppression region that suppresses plastic flow of the material, and a protrusion forming region where the protrusion is formed,
The flow suppression region is a mold formed so that a surface friction coefficient thereof is higher than a surface friction coefficient of the protrusion forming region.   The mold according to claim 1, wherein the flow suppression region is disposed around the protrusion forming region.   The mold according to claim 1, wherein a plurality of uneven portions are formed in the flow suppression region.   The mold according to any one of claims 1 to 3, wherein the protrusion forming region is formed at a substantially central portion of the pressing surface.   The mold according to any one of claims 1 to 4, wherein a surface friction coefficient of the protrusion forming region is 0.01 to 0.5. A molding method for molding a product having a protrusion using the mold according to any one of claims 1 to 5,
A flow step of plastically flowing the material by pressurizing the material placed on the pressure surface of the die with the pressure surface of the punch;
A forming method comprising: a flow suppressing step of suppressing plastic flow of the material by the flow suppressing region having a higher surface friction coefficient than the protrusion forming region.