CN114867589A

CN114867589A - Method for manufacturing mould box and plate body product for stamping machine

Info

Publication number: CN114867589A
Application number: CN202180007198.4A
Authority: CN
Inventors: 济藤友明; 首藤祥史
Original assignee: Japan Technology Management Co ltd
Current assignee: Ningbo Motong Composite Materials Co ltd
Priority date: 2020-12-28
Filing date: 2021-10-15
Publication date: 2022-08-05
Anticipated expiration: 2041-10-15
Also published as: WO2022034929A1; CN114867589B; JP2022104168A; JP6923870B1

Abstract

The invention can obtain a flat plate with high outer edge quality besides plane precision at low cost. A workpiece (5) is formed into a plate product (50) with high planar accuracy by press forming using a pair of upper and lower dies including a first die (2) having a flat pressing surface and a second die (3) having a flat pressing surface facing the pressing surface, and a molding box (4). The molding box (4) has a closed inner wall (41) surrounding the outer edge of the plate body product (50) to be molded, the thickness t in the direction perpendicular to the pair of molds (2, 3) is equal to the thickness of the plate body product (50) to be molded, and the inside of the inner wall (41) of the molding box has a size larger than the outer edge (51) of the plate body product (50) by an amount a removed for adjustment to the size of the plate body product to be molded.

Description

Method for manufacturing mould box and plate product for punching machine

Technical Field

The present invention relates to a die box for a press working machine for forming a workpiece into desired products of various shapes by press forming, and a method for manufacturing a plate product using the die box.

Background

Various dies are used for processing by a press. Generally, press working is a method of obtaining a worked product having a desired shape by using a pair of dies having a worked shape, such as shearing, punching, and drawing.

A plate (flat plate) with high plane accuracy is also produced by press working.

In general, a press machine used for such working is configured to perform predetermined flattening and molding by placing a work piece such as a metal plate or a preform between a pair of upper and lower dies including a first die having a cavity (die) having a desired plate size and a second die having a core (punch) corresponding to the cavity and applying a compressive force.

In particular, in the production of precision flat plates made of CFRP or the like, a prepreg is molded by heating and compressing it with a pair of upper and lower dies. The mold is formed with a cavity and a core of product dimensions, and a preform as a raw material is placed between the molds and compressed and heated to obtain a predetermined molded product.

In press molding of a prepreg made of a resin-reinforced plastic such as CFRP, resin voids (void) and fiber alignment are likely to occur at the outer edge of a molded product due to resin flow and fiber movement caused by heating and compression of a press die (in this case, a hot plate).

The dimensional accuracy of the molded product is lowered due to the irregularity of the voids and fibers, and the accuracy of the outer edge and the surface is deteriorated.

Although not directly related to the present invention, patent document 1 can be cited as a means for avoiding product defects caused by laminate displacement due to molten resin when the multilayer prepreg is heated and compressed by a press machine.

Patent document 1 discloses a means for locking the periphery of a multilayer prepreg with a tape-like material made of aramid fibers in order to suppress interlayer displacement caused by molten resin when the prepreg is multilayer-molded.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Hei 05-26363

Disclosure of Invention

In order to produce a flat product having a high outer edge and a high planar accuracy using a press machine using a preform as a raw material, it is not practical to prepare a mold having a cavity and a core formed therein depending on the size of the product. The manufacturing cost of the mold occupies a large portion of the product cost.

Therefore, this becomes a factor that hinders cost reduction of a processed product using the prepreg as a raw material.

The present invention has been made to solve the above problems by providing flat plates (hot plates) as upper and lower molds, inserting a molding box (a type of cover) having an inner dimension increased by a margin slightly larger than that of a final product between the molds, molding the flat plates so that the plane accuracy and the outer dimension reach predetermined values, and then adjusting the margin to obtain flat plates having high outer edge quality in addition to the plane accuracy at low cost.

The following describes a typical structure of the present invention. In the following description, reference numerals used in corresponding embodiments are given to facilitate understanding of the present invention, but the present invention is not limited to the configurations indicated by the reference numerals.

The present invention relates to a molding box 4 used in a press working machine for forming a work material 5 into a plate product 50 having high planar accuracy by press forming using a pair of upper and lower dies including a first die 2 having a flat pressing surface and a second die 3 having a flat pressing surface opposed to the pressing surface.

The molding box 4 has a closed inner wall 41 surrounding the outer edge of the plate product 50 to be molded, the thickness t in the direction perpendicular to the pair of molds is equal to the thickness of the plate product 50 to be molded, and the width of the inner side of the inner wall 41 has a size larger than the outer edge 51 of the plate product 50 by the amount α removed for adjusting the size of the plate product to be molded.

The work 5 has a laminated structure including at least one layer formed of a prepreg, the pair of

dies

2 and 3 are hot plates, and the plate product 50 is a rectangular plate having an edge perpendicular to a plane.

The width dimension inside the molding box 4 is set to a size including a void 7 where resin of a prepreg material constituting the workpiece 5 is generated and accumulated in the vicinity of the boundary with respect to the molding box 4 and a region where the fiber alignment irregularity region is adjusted and removed.

According to experience, it is known that: in the heat compression molding of the prepreg, voids and long fibers remaining in the outer edge after molding are unevenly aligned and are within a range of 1mm to 10 mm.

A plurality of types of the mold boxes are prepared corresponding to a plurality of plate products having different sizes, and are selected for use for each product to be processed. The margin of adjustment may be determined according to the properties of the resin constituting the workpiece 5, whether the fibers as the matrix are long fibers or short fibers, the thickness of the fibers, or the like.

The present invention is a method for manufacturing a sheet product, in which a workpiece is molded into a sheet product with high planar accuracy by using a pair of upper and lower dies including a first die having a flat pressing surface and a second die having a flat pressing surface opposed to the pressing surface, and a mold box,

the method for manufacturing a plate product is characterized in that,

the molding box is composed of: a closed inner wall surrounding an outer edge of a plate product to be molded, the inner wall having a thickness in a direction perpendicular to the pair of molds equal to a thickness of the plate product to be molded, and an inner side having a width configured to be larger than a size of the outer edge of the plate product by an amount removed for adjusting a size of the plate product to be molded,

the manufacturing method of the plate body product comprises the following steps:

a molding box arranging step of arranging the molding box between the first mold and the second mold and on a pressing surface of the first mold;

a workpiece placement step of placing a workpiece on a molding box placed between the first mold and the second mold;

a press working step of lowering the second die and heating and pressurizing the workpiece; and

and adjusting the size of the plate body product to be formed by adjusting the processed workpiece subjected to the stamping processing.

The present invention is not limited to the above-described configuration and the configuration of the embodiment described in the embodiment described below, and it is needless to say that various modifications can be made without departing from the technical idea of the present invention.

Effects of the invention

According to the configuration of the present invention, a flat plate having high outer edge accuracy in addition to the flat surface accuracy can be obtained by disposing a molding box having an inner dimension slightly larger than the dimension of the final product between a pair of molds, molding the flat plate so that the flat surface accuracy and the outer dimension reach predetermined values, and then adjusting the allowance.

A plurality of molding boxes are prepared in advance according to a flat plate product of a desired size, so that a desired plate product can be molded without exchanging molds.

Thus, a high-precision plate can be obtained at low cost without using an expensive mold.

Drawings

Fig. 1 is an explanatory view of a press machine using a flask according to the present invention.

Fig. 2 is an explanatory diagram of the dimensional relationship between the molding box and the plate product according to the present invention.

Fig. 3 is a diagram showing a flow of a method for manufacturing a plate product according to the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings of the examples.

Examples

Fig. 1 is an explanatory view of a press machine using a mold box according to the present invention, fig. 1(a) is a schematic side view, fig. 1(b) is a plan view of the mold box, and fig. 1(c) is a perspective view of the mold box.

This punching press mechanism becomes: comprising a first die 2 and a second die 3, the second die 3 being lowered with respect to the first die 2 with a shaft 6 as a guide. The second mold 3 is lowered (compressed) and raised by a slide (not shown) provided above the second mold 3. The opposed surfaces of the first mold 2 and the second mold 3 are high-precision flat surfaces. Reference numeral 1 denotes a base.

A molding box 4 is disposed between the first mold 2 and the second mold 3, and a workpiece 5 is press-fitted into the molding box 4. The molding box 4 has a closed inner wall 41 surrounding an outer edge 51 of the plate product 50 to be molded, and a thickness t (refer to fig. 2) in a direction perpendicular to the pair of molds is equal to a thickness of the molded plate product 50. Also, the inner side of the inner wall 41 has a size larger than the outer edge 51 of the plate product 50 in order to remove the amount α for adjustment to the size of the plate product to be molded.

In the present embodiment, the work 5 is a laminate having a 3-layer structure in which a thin graphite material is sandwiched by 2 carbon fiber preforms in one direction, but is not particularly limited, and a single-layer body, a laminate, or a viscous resin may be used as the work 5. In the example, the prepreg, the graphite material, and the prepreg were stacked in this order in the molding box 4.

The prepreg used as the material of the workpiece 5 includes, for example, a semi-finished product (pre-molding member: molded article) obtained by impregnating a thermosetting resin (epoxy resin, vinyl ester resin, polyimide resin, or the like) or a thermoplastic resin (polyamide resin, polycarbonate resin, or the like) with a fiber material (for example, synthetic resin fibers such as carbon, glass, boron, aramid, nylon, or the like) as a matrix, and the fibers such as carbon may be fibers in one direction or may be fibers in two directions intersecting perpendicularly. When a plurality of fibers in the same direction are used as the fibers such as carbon, the carbon fibers may be in the same direction or in different directions. The thickness is not particularly limited, and may be, for example, 0.05mm to 10mm (0.2 mm in the example).

The graphite material is not particularly limited, and for example, a graphite sheet having a thickness of 0.1mm to 10mm (in the examples, a graphite sheet having a thickness of 0.4 mm) or the like can be used.

In the present embodiment, the work 5 is a laminate having a 3-layer structure in which a thin graphite material is sandwiched by 2 carbon fiber preforms in one direction, but in addition to this, a mixture of graphite powder or carbon powder and a resin (thermosetting resin, thermoplastic resin) having a viscous state may be used as the work 5, and there may be mentioned: a laminate obtained by laminating a sheet obtained by impregnating a fibrous base material in a mat shape with an unsaturated polyester or the like, i.e., smc (sheet Molding compound) monomer, and short fibers or long fibers and resin (thermosetting resin or thermoplastic resin) sheets.

The pair of

molds

2 and 3 are hot plates that are heated to a high temperature by a heating mechanism not shown. The plate product 50 formed into a final product by the press machine is a rectangular plate whose end edge is perpendicular to a plane.

The margin provided by α (see fig. 2(a)) for the width dimension inside the molding box 4 is set to a size including a region where voids 7 or fiber irregularities as a matrix are generated in the vicinity of the boundary with respect to the molding box 4 due to a prepreg or a viscous resin constituting the workpiece 5.

In particular, when long fibers such as carbon fibers are used, the fibers are likely to be misaligned due to their anisotropy, and therefore, the misaligned fiber regions are adjusted to a size that eliminates them.

A plurality of types of the molding boxes 4 are prepared corresponding to a plurality of plate products having different dimensions (length, width, and thickness in the case of a rectangle; and dimensions and thicknesses of respective sides in the case of a polygon other than a rectangle), and are selected for use according to each product to be processed.

Next, a specific dimensional example will be described with reference to fig. 2. Here, as the

work material

5, 2 preforms having a thickness of 0.2mm were used, and graphite having a thickness of 0.4mm was used therebetween, and a high-precision flat plate having a length (L) × width (W) × thickness (t: height) of 50mm, 50mm W, and 0.6mm t of a final product was produced by press working.

The dimensions of the flask 4 used for the production of this product were set to L ═ 50mm + α (═ 1mm) ] × W ═ 50mm + α (═ 1mm) ] × [ t (═ 0.6mm) ].

The thickness is set to the same size as the product in order to perform preprocessing in advance in such a manner that the size of the preform is just appropriate with respect to the inner wall of the molding box 4.

The resin flows in the longitudinal and transverse directions due to the heated compression of the punch, however, the flow is prevented by the inner wall 41 of the molding box 4. The resin flowing contains voids (air bubbles) and moves to the outer edge due to compression and concentrates on the boundary with the inner wall of the molding box 4. In addition, when long fibers are used as a matrix, the arrangement of the fibers may be disturbed (irregular) in the direction of the outer edge of the product due to compression.

According to experience, it is known that: in the flat plate processing of this size, the above-mentioned voids and fiber irregularities are within a range of 1mm in the outer edge, and therefore α is 1 mm. However, the thickness may be 2mm or more depending on the properties of the resin.

The region (α ═ 1mm) of the excess that has overflowed the outer edge of the processed product is removed by press working while the resin is cured and returned to normal temperature. For the adjustment, a precision cutting machine such as a laser cutter is used.

According to the present embodiment, flat plates of various sizes can be manufactured at low cost without replacing the mold itself.

Next, a method for manufacturing a plate product according to the present invention will be described with reference to fig. 3.

In the method for manufacturing a plate product according to the present invention, a pair of upper and lower dies including a first die 2 having a flat pressing surface and a second die 3 having a flat pressing surface facing the pressing surface, and a molding box 4 are used.

The molding box 4 is constituted by: a closed inner wall 41 surrounding the outer edge of the molded plate product, the inner wall having a thickness in a direction perpendicular to the pair of molds equal to the thickness of the molded plate product, and an inner width configured to be larger than the outer edge of the plate product by an amount removed for adjustment to the size of the molded plate product.

In the production of the plate product according to the present invention, first, the molding box 4 is disposed between the first die 2 and the second die 3 and on the pressing surface of the first die 2 (molding box disposing step: S1 in fig. 3).

Next, the work 5 is placed in the molding box 4 disposed between the first mold 2 and the second mold 3 (work placing step: S2 of fig. 3).

Then, the second die 3 is lowered to heat and press the work 5 (press working step: S3 in fig. 3).

After the heating and pressing, the second mold is raised, and when the resin of the work material 5 is cured and returns to the vicinity of the normal temperature, the molding box 4 is removed (optional molding box removing step: S4 in fig. 3).

Finally, the workpiece 5 is removed from the die, cut by a precision cutting machine such as a laser cutter, and adjusted to the dimensions of the plate product 50 to be formed (adjustment step: S5 in fig. 3), thereby obtaining the plate product 50.

Industrial applicability

In the above embodiment, the fiber-reinforced composite resin material was described as a workpiece, but the present invention can also be applied to a drawing machine that uses various materials as workpieces, such as a resin single sheet, a glass composite sheet, a metal sheet, a resin-metal composite sheet, and a composite metal sheet, which do not use fibers as structural materials.

Description of the reference numerals

1 … base station

2 … first model (Flat plate)

3 … second mould (Flat)

4 … type box

41 … closed inner wall

5 … workpiece

50 … board product

51 … outer edge of plate product

6 … axle

7 … irregular edge

Claims

1. A method for manufacturing a plate product, wherein a work piece is molded into a plate product with high planar accuracy by using a pair of upper and lower dies including a first die having a flat pressing surface and a second die having a flat pressing surface opposed to the pressing surface, and a molding box,

the method for manufacturing a plate product is characterized in that,

the molding box has a closed inner wall surrounding an outer edge of a plate product to be molded, a thickness in a direction perpendicular to the pair of molds is equal to a thickness of the plate product to be molded, an inner width is larger than the outer edge of the plate product in order to adjust an amount removed for a size of the plate product to be molded, an area of a pressing surface of the second mold is larger than an area surrounded by the inner wall of the molding box,

a mold arrangement step of arranging the mold between the first mold and the second mold and on a pressing surface of the first mold;

a workpiece placement step of placing a workpiece in a molding box disposed between the first mold and the second mold;

a workpiece arranging step of arranging a workpiece in a molding box arranged on the pressing surface of the first mold;

an adjusting step of adjusting the punched workpiece to the size of the plate product to be formed,

the inside width dimension of the molding box is a dimension including a region which is generated by the workpiece and left in the vicinity of the boundary of the molding box and is adjusted to be removed.

2. The method of manufacturing a plate product according to claim 1,

the pair of molds are hot plates, and the plate body product is a rectangular plate with the end edge vertical to the plane.

3. The method for manufacturing a plate product according to claim 1 or 2,

a plurality of types of the molding boxes are prepared corresponding to a plurality of plate products having different sizes, and the molding boxes are selectively used for each product to be processed.