JP2019136742A - Manufacturing method of hot-stamp molding, metal mold for hot-stamp molding and hot-stamp molding manufactured by using the metal mold - Google Patents

Abstract

To provide a manufacturing method of a hot-stamp molding which can prevent the generation of a dross at laser cutting, and a cutting failure while maintaining productivity and suppressing a cost, a metal mold for the hot-stamp molding and the hot-stamp molding manufactured by using the metal mold.SOLUTION: A manufacturing method of a hot-stamp molding 10 which is formed by cutting a part of a press-molded stamp material 30 by a laser includes: a press process for pressing a plate thickness of the hot-stamp material in a prescribed region so as to be thinner than that of its peripheral region when press-molding the hot-stamp material to a prescribed shape by using a metal mold 20; and a cut process for cutting the hot-stamp material by radiating the laser 56 to the prescribed region.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a hot stamp molded product in which a part of a hot stamped material that has been press molded is cut with a laser, a mold for hot stamp molded product, and a hot stamp molded product molded using the mold. .

  The hot stamped material that has been hot-pressed is a high-strength member. Therefore, if the trimming or punching after pressing is performed by shearing using a die, the die life is significantly reduced. Therefore, generally, cutting with a laser is performed (for example, Patent Document 1).

  Laser cutting can eliminate the maintenance of the shearing mold caused by shearing. Moreover, it is possible to prevent the occurrence of delayed fracture of a hot stamped molded product based on the residual stress during shearing.

Japanese Patent Laid-Open No. 2006-101604

  However, if the plate thickness of the hot stamp material is changed by press molding and the plate thickness of the cut portion after press working is increased, an increase in the amount of dross generated during laser cutting or a cutting failure occurs.

  Countermeasures for such problems include reducing the cutting speed or increasing the laser output. However, if the cutting speed is slowed down, the productivity will be reduced, so an increase in equipment is required to maintain the productivity. Moreover, expensive equipment investment is required to increase the laser output.

  The present invention has been made in view of the above-mentioned problems, and for hot stamp materials having a relatively large plate thickness, while maintaining productivity and reducing costs, generation of dross at the time of laser cutting or cutting failure An object of the present invention is to provide a method for manufacturing a hot stamp molded article that can prevent the above, a mold for a hot stamp molded article, and a hot stamp molded article molded by the mold.

  In order to achieve the above object, a method for manufacturing a hot stamp molded product according to claim 1 is a method for manufacturing a hot stamp molded product in which a part of a hot stamped material that has been press molded is cut by a laser. When the hot stamp material is press-molded into a predetermined shape with a mold, a pressing step of pressing the hot stamp material so that the thickness of the predetermined region is thinner than the peripheral region; and the predetermined value of the hot stamp material And a cutting step of cutting the region by irradiating a laser.

  According to this configuration, in the pressing process, a predetermined region of the hot stamp material, that is, a region to be laser cut is formed with a thin plate thickness, and then the region is laser cut. On the other hand, it is possible to prevent the occurrence of dross at the time of laser cutting and cutting failure while maintaining productivity and reducing costs such as capital investment.

  The invention according to claim 2 is the manufacturing method according to claim 1, wherein the pressing step positions the predetermined region of the hot stamp material on a convex portion formed on an inner surface of the mold. By pressing, a concave portion is formed only on one surface of the hot stamp material to reduce the plate thickness of the predetermined region.

  According to this configuration, the plate thickness of the predetermined region to be laser cut can be easily reduced by positioning and pressing the predetermined region of the hot stamp material on the convex portion formed on the inner surface of the mold.

  According to a third aspect of the present invention, in the manufacturing method according to the second aspect, the convex portion is formed in a region where the thickness of the hot stamp material is increased by press molding.

  According to this configuration, when the hot stamp material is bent by press molding and the plate thickness changes and the plate thickness of the laser cutting region increases, the plate thickness of the region to be laser cut by the convex portion of the mold Can be set to an appropriate thickness.

  According to a fourth aspect of the present invention, in the manufacturing method according to the second or third aspect, in the trim step, the laser is irradiated from a surface opposite to the surface on which the concave portion is formed. .

  According to this configuration, it is possible to cause the dross generated when the laser is cut to enter the recess of the hot stamp material, and as a result, it is possible to suppress problems associated with an increase in the plate thickness due to the dross.

  The invention according to claim 5 is the manufacturing method according to claim 4, wherein the concave portion of the hot stamp material has an inclined or stepped shape in which the depth on the trim side is shallower than the product side. It has a bottom surface.

  According to this configuration, it is possible to prevent dross from adhering to the product by causing the dross generated by laser cutting to flow to the trim side removed from the product.

  Moreover, the invention according to claim 6 is the manufacturing method according to any one of claims 2 to 5, wherein the hot stamp material cut by the laser has a recessed portion due to the recess at an edge portion. Then, after the cutting step, the hot stamp material and another steel plate material are laminated in a state where the hollow portion faces the steel plate material, and the hot stamp material and the steel plate material are formed in a region where the hollow portion is not formed. It includes a welding process for welding.

  According to this configuration, since the dents of the hot stamp material are laminated and welded in opposition to other steel plate materials, the dents do not appear on the product surface, and the aesthetics of the product can be kept good. it can. In addition, since the dross generated by the laser cutting fits in the recess, it is possible to prevent the dross from coming into contact with the steel plate material and causing poor welding when laminated with another steel plate material.

  The hot stamping molded product mold according to claim 7 is a hot stamping molded product mold comprising a fixing mold and a moving mold facing the fixing mold. The plate thickness of the hot stamp material on the inner surface of one of the mold and the transfer mold, corresponding to a predetermined region of the hot stamp material placed in the mold It is characterized in that a convex portion having a lower height is provided.

  According to this configuration, when the hot stamp material is press-molded, the concave portion is formed in the predetermined region of the hot stamp material by the convex portion formed on the inner surface of the mold, and the plate thickness of the predetermined region is thinned. be able to.

  The invention according to claim 8 is a hot stamping molded product formed by using the hot stamping molded product mold according to claim 7, which has a plating film on its surface and is laser cut. The thickness of the edge portion is characterized by being thinner than the thickness of the peripheral region.

  According to this configuration, since the plate thickness of the edge portion of the hot stamped product that has been laser cut is reduced, the area of the laser cut portion that does not have a plating film can be reduced to improve the corrosion resistance. it can.

  According to the hot stamping molded product mold according to the present invention and the hot stamping molded product molded by the mold, it is possible to maintain the productivity and reduce the cost for the hot stamping material having a relatively large plate thickness. Generation of dross at the time of laser cutting and cutting failure can be prevented.

Sectional drawing of the hot stamping molded article which is one embodiment of this invention. The principal part expanded sectional view of the hot stamping molded article shown in FIG. Explanatory drawing of the metal mold | die for hot stamping molded products which is one embodiment of this invention. The perspective view which shows the hot stamped material press-molded. The figure explaining the cutting process of a hot stamping molded article. The principal part expanded sectional view of the hot stamp material in a cutting process. Sectional drawing which shows the welding process of a hot stamping molded article. The principal part expanded sectional view which shows the modification of a hot stamp molded product.

  FIG. 1 is a cross-sectional view of a hot stamp molded product according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of the hot stamp molded product shown in FIG. The hot stamping molded product 10 is composed of a steel plate 12 formed into a predetermined shape by hot pressing, and has plated films 14 and 15 made of, for example, aluminum on both surfaces thereof. In addition, description of the plating films 14 and 15 is abbreviate | omitted in FIGS. The hot stamping molded product 10 of the present embodiment is formed in a long shape, and the cross-sectional shape orthogonal to the longitudinal direction is a hat (hatched hat) shape. Such a hot stamp molded article 10 can be suitably used as a vehicle reinforcement (reinforcing member), for example.

  In the hot stamped molded product 10, the plate thickness h 1 of the edge portion that has been laser-cut is thinner than the plate thickness h 2 of the peripheral region 16. In the present embodiment, the end of one surface (hereinafter referred to as the first surface 10a) of the hot stamp formed product 10 is formed flat, and the end of the other surface (hereinafter referred to as the second surface 10b) is formed. By forming the hollow portion 11 so as to be recessed from the peripheral region 16, the plate thickness h <b> 1 is reduced.

  A part of the hot stamp molded product 10 is obtained by press-molding a hot stamp material 30 as a base material using a hot stamp molded product mold 20 shown in FIG. 3 (hereinafter simply referred to as “mold 20”). Is formed by laser cutting. 3A is a cross-sectional view of the mold 20, and FIG. 3B shows a state in which the mold 20 is clamped.

  The mold 20 includes a lower mold (fixing mold) 21 and an upper mold (moving mold) 25 disposed to face the lower mold 21.

  Convex portions 22 and 23 are formed on the inner surface 21 a of the lower mold 21 and in a region corresponding to a predetermined region of the hot stamp material 30. Here, the predetermined area of the hot stamp material 30 is an area that is laser-cut after the hot stamp material 30 is press-molded. In the following description, this predetermined area is referred to as a cutting area.

  In the present embodiment, the regions where the convex portions 22 and 23 are provided correspond to regions where the plate thickness of the hot stamp material 30 increases due to bending deformation when the hot stamp material 30 is press-molded. The height of the convex portions 22 and 23 is set to be smaller than the plate thickness of the hot stamp material 30 before press molding. Further, the widths of the convex portions 22 and 23 are set larger than the cutting width by a laser cutting device 50 described later.

  The upper mold 25 is configured to be movable up and down so as to approach and separate from the lower mold 21 by a pressing device (not shown). On the inner surface 25a of the upper mold 25, the convex portions 22 and 23 of the lower mold 21 and the region facing the peripheral portion thereof are formed in a flat shape without irregularities.

  Next, the manufacturing method of the hot stamping molded article 10 will be described in detail with reference to FIGS.

  First, as shown in FIG. 3A, with the upper mold 25 raised, the hot stamp material 30 heated to a high temperature and softened is placed on the inner surface 21a of the lower mold 21 (placement step). ). The hot stamp material 30 is made of a steel plate having plating films on both sides, and is placed so that a cutting region to be cut in a cutting process described later and the convex portions 22 and 23 of the lower mold 21 face each other.

  Thereafter, as shown in FIG. 3B, the upper die 25 is lowered to press-mold the hot stamp material 30 (pressing process). The hot stamp material 30 is cooled and quenched in the mold 20 simultaneously with the molding.

  As shown in FIG. 4, concave portions 32 and 33 corresponding to the convex portions 22 and 23 of the mold 20 are formed in the cutting region of the hot stamp material 30 after press molding. It is thinner than the surrounding area. The recesses 32 and 33 in the illustrated example are grooves having a substantially rectangular cross section, and the recesses 32 and 33 extend along the cutting line of the hot stamp material 30.

  The press-molded hot stamp material 30 is laser processed by the laser cutting device 50 to remove a part thereof (cutting process). FIG. 5 is a diagram for explaining a cutting process of the hot stamp material 30 and shows a state of cutting in one of the recesses 32, 33. The other recess 33 is similarly laser-cut.

  The laser cutting device 50 includes a laser processing head 54 connected to a laser oscillator (not shown) and a driving unit. The laser processing head 54 is moved to the cutting region of the hot stamp material 30 by the driving unit, and irradiates the hot stamp material 30 with the laser 56 generated by the laser oscillator from the nozzle 54 attached to the tip. As shown in FIG. 5A, the laser 56 irradiates the surface 30a opposite to the surface 30b on which the concave portion 32 is formed, and as shown in FIG. 5B, in the region where the concave portion 32 is formed. The product is separated into a hot stamp molded product 10 to be a product and a trim portion 40 to be removed from the product. In the end edge portions of the hot stamp molded product 10 and the trim portion 40, recessed portions 11 and 42 which are part of the recess 32 are formed, respectively, and the plate thickness of the end edge is reduced.

  Next, laser processing of the hot stamp material 40 will be described in detail with reference to FIG. 6A is a cross-sectional view of a main part of the hot stamp material 30 before laser cutting, and FIG. 6B is a cross-sectional view of a main part of the hot stamp material 30 after cutting.

  As described above, the width W1 of the recess 32 of the hot stamp material 30 is set wider than the width W2 of the laser 56 to be irradiated. Moreover, the width dimension D of the hollow part 11 in the hot stamp molded product 10 is set to be equal to or less than a predetermined dimension. This predetermined dimension is, for example, 1 to 5 mm, and is smaller than the dimension from the edge 17 of the product after laser cutting (that is, the hot stamped product 10) to the welded portion to which spot welding or the like is performed. Is set.

  As shown in FIG. 6B, in laser processing, dross 19 may be generated in which the melt of the hot stamp material 30 is re-solidified and adhered in the vicinity of the cut portion. In the present embodiment, by irradiating the laser 56 from the surface 30a opposite to the recess 32, the generated dross 19 can enter the recess 32, that is, the recess 11 and / or the recess 42). it can.

  In the manufacturing method of the hot stamped article 10 described above, since the laser processing is performed after the cutting region of the hot stamp material 10 is made thinner than the peripheral region in the pressing step, the hot stamp material having a relatively large plate thickness. On the other hand, good laser processing can be performed without reducing the laser cutting speed or separately adding a high-power laser cutting device. Thereby, it is possible to prevent cutting defects in laser processing and maintain productivity while suppressing an increase in manufacturing cost such as expensive capital investment and increase in personnel.

  Further, the concave portions 32 and 33 of the hot stamp material 30 can be formed with a simple structure for forming convex portions on the mold 20, and further, in the pressing process, the hot stamp material 30 is heated and softened. Therefore, the recesses 32 and 33 can be easily formed.

  In addition, it is possible to prevent dross from occurring during laser processing accompanying an increase in the plate thickness. In particular, in the press molding of the hot stamp material 30, a partial increase or decrease in the plate thickness due to the bending of the hot stamp material 30 occurs, but the region where the plate thickness increases and the cutting region of the hot stamp material 30 are divided. Even in the case of overlapping, it is possible to adjust the thickness of the cutting region to a thickness suitable for laser processing by using the above-described mold 20.

  Further, in the laser processing, the generated dross 19 can enter the recess 32 by irradiating the laser 56 from the surface 30 a opposite to the recess 32. Thereby, it is possible to prevent the malfunction at the time of welding of the hot stamping molded article 10 by the dross 19.

  FIG. 7 is a cross-sectional view showing a welding process in which the hot stamped article 10 is welded to another steel plate material 60. The hot stamping molded article 10 includes a first electrode 62 and a second electrode 63 that is disposed to face the first electrode 62 and is laminated with the steel plate material 60 with the recess 11 facing the steel plate material 60. It is welded and joined by a spot welding device. Welding is performed in a non-formation region of the recess 11. In the hot stamped molded product 10 of the present embodiment, the dross 19 is accommodated in the recessed portion 11 at the edge, so that the dross 19 comes into contact with the surface 60a of the steel plate material 60 when welding with the steel plate material 60. It is possible to prevent surface contact between them and cause poor welding. Moreover, since the hollow part 11 does not appear on the product surface, the aesthetics of the product can be kept good.

  In the above-described embodiment, the recesses 32 and 33 are formed in the region to be trimmed in the hot stamp material 30. However, instead of or in addition to this, cutting in which the punching process is performed in the hot stamp material 30. Laser cutting may be performed after forming a recess in the region by using the mold 20 to make it thin.

(Modification)
Next, a modified example of the hot stamp molded product 10 of the present invention will be described. 8A and 8B are enlarged cross-sectional views of the main parts showing modifications of the hot stamp molded product 10, respectively. In FIG. 8, the same elements as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 8, the state after laser cutting is indicated by a solid line, and the shape of the hot stamp material 30 before cutting is indicated by a broken line.

  In Modification 1 shown in FIG. 8A, the bottom surface of the concave portion 32 of the hot stamp material 30 is formed in an inclined shape by the shape of the convex portion 22 provided on the mold 20. The inclined bottom surface is inclined so that the depth decreases from the product side toward the trim side. When the hot stamp material 30 is irradiated with the laser 56 from the surface 10 a opposite to the recess 32, the melt flows to the trim side along the inclined surface of the recess 32, and the dross 19 adheres to the recess 42 of the trim portion 40. To do. Thereby, it can prevent that the dross 19 adheres to the hot stamp molded product 10 used as a product.

  In the second modification shown in FIG. 8B, the bottom surface of the concave portion 32 of the hot stamp material 30 is formed in a stepped shape due to the shape of the convex portion 22 provided on the mold 20. The step bottom surface has a step shape in which the depth decreases from the product side toward the trim side. When the laser beam 56 is irradiated onto the hot stamp material 30 from the surface 10 a, the melt flows along the step of the concave portion 32 toward the trim side, and the dross 19 adheres to the recess 42 of the trim portion 40. Thereby, it can prevent that the dross 19 adheres to the hot stamp molded product 10 used as a product.

  The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the spirit of the invention.

  For example, in the above-described embodiment, the protrusions 22 and 23 are provided on the lower mold 21, but instead, the protrusions are provided on the inner surface 25 a of the upper mold 25, and the lower mold 21 facing this is provided. The inner surface 21a may be planar. Alternatively, the cutting region of the hot stamp material 30 may be formed thin by providing convex portions on both the upper die 25 and the lower die 21.

10 Hot Stamp Molded Product 11 Recess 20 Mold (Mold for Hot Stamp Molded Product)
21 Lower mold 22, 23 Convex part 25 Upper mold 30 Hot stamp material 32, 33 Concave part 50 Laser cutting device

Claims (8)

A method of manufacturing a hot stamping molded product in which a part of a hot stamped material that has been press molded is cut by a laser,
When the hot stamp material is press-molded into a predetermined shape with a mold, a pressing step for pressing the hot stamp material so that the plate thickness of the predetermined region is thinner than the peripheral region;
And a cutting step of cutting the predetermined region of the hot stamp material by irradiating a laser to the predetermined region.   In the pressing step, the predetermined region of the hot stamp material is positioned on a convex portion formed on the inner surface of the mold and pressed to form a concave portion only on one surface of the hot stamp material. 2. The method for manufacturing a hot stamped article according to claim 1, wherein the thickness of the predetermined region is reduced.   3. The method for manufacturing a hot stamped product according to claim 2, wherein the convex portion is formed in a region where the thickness of the hot stamp material is increased by press molding.   4. The method for manufacturing a hot stamped article according to claim 2, wherein, in the cutting step, a laser is irradiated from a surface opposite to the surface on which the concave portion is formed.   5. The method of manufacturing a hot stamp molded product according to claim 4, wherein the concave portion of the hot stamp material has an inclined or stepped bottom surface that has a shallower depth on the trim side than on the product side. . The hot stamp material cut by the laser has a recessed portion by the concave portion at the edge portion,
After the cutting step, the hot stamp material and another steel plate material are laminated in a state where the hollow portion faces the steel plate material, and the hot stamp material and the steel plate material are welded in a region where the hollow portion is not formed. The manufacturing method of the hot stamping molded article of any one of Claims 2-5 including the welding process to perform. In a hot stamping molded product mold comprising a fixing mold and a moving mold facing the fixing mold,
An inner surface of one of the fixing mold and the moving mold, and in a region corresponding to a predetermined region of the hot stamp material placed in the mold, the hot stamp material A mold for a hot stamping molded product, wherein a convex portion having a height lower than the plate thickness is provided. A hot stamp molded article molded using the hot stamp molded article mold according to claim 7,
A hot stamping product having a plating film on a surface thereof, wherein a plate thickness of an edge portion laser-cut is thinner than a plate thickness of a peripheral region thereof.

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