JPH0321328B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for forming a bent part without losing the properties of a laminated material, and in particular, prevents breakage, peeling, slippage, etc. of the surface material that is likely to occur on the back side of the bent part. The present invention relates to a bending method that can effectively prevent this.

Development of new highly functional materials is underway by effectively utilizing known materials. One example is the development of composite materials by laminating different materials (sometimes the same materials), and products made by combining metal materials, synthetic resin materials, paper, etc. in various ways and using various joining methods are provided. has been done. Examples of typical composite materials include: (1) A laminated steel plate with a synthetic resin film as the core material and steel plates bonded to both surfaces.(2) Composite aluminum foil with a foamed resin core material and aluminum foil bonded to both surfaces. (3) Examples include vibration-damping steel plates made by bonding steel plates together with a special adhesive.

These composite materials are used in a wide range of applications by making use of their respective material properties, but depending on the application and application site, they are often subjected to various processing, and in particular, they are frequently subjected to bending processing. However, compared to conventional single materials, the molding performance is quite different, especially on the back side of the bending part, where the surface material (more precisely, the back side material) breaks and the core material and inner layer material are exposed to the surface. In addition, the surface material on the ventral surface side may be compressed and peel or slip (slip), resulting in floating or deformation of the surface material. In other words, when bending laminated materials, the neutral point of strain tends to deviate from the center of the entire plate thickness and is located in the center of each individual material, which causes a shift phenomenon due to slippage of each layer at the bending end. appears. Therefore, in an attempt to eliminate such a shift phenomenon, bending is sometimes performed by applying excessive compression, but in this case, a break occurs on the back side of the bent portion.

These difficulties in bending workability have significantly narrowed the scope of application of composite materials despite efforts to improve their functionality, and have become a serious bottleneck in the expanded use of composite materials.

One way to overcome these difficulties is to form a U-shaped cutting groove A on the ventral side of the bent portion as shown in Figure 1 to reduce the bending radius. In this method, the cutting process is often applied not only to the surface material 1 but also to the core material 2, so there is a problem that the essential properties of the composite material are lost, and there are also problems with the accuracy of the cutting process. Moreover, the bending radius cannot be made sufficiently small, and the bending workability has not been evaluated as improved. In addition, 3 in FIG. 1 indicates the surface material on the back side, and FIG. 2 shows the state in which the bending process is completed.

The present invention was developed in consideration of this situation, and it is a bending process that maintains the properties of a composite material as much as possible and that does not cause breakage, peeling, or shearing even when the bending radius is reduced. The purpose is to provide a method.

The method of the present invention that satisfies the above objectives is as follows:
At least one parallel straight groove is formed on the ventral side of the bent portion of the laminated material by press working along both sides of the planned bending line, and the bending process is performed on the planned bending line existing between the straight grooves. The gist lies in the points.

Next, the configuration and effects of the present invention will be explained with reference to the drawings showing embodiments. FIG. 3 is a perspective view showing the first embodiment, in which one straight groove P ₁ and one P ₂ are formed on each side of the bending line C. straight groove
The cross-sectional shape of P ₁ and P ₂ can be freely selected such as round bottom type, flat bottom type, V type, or a combination of these types, and the width, length, depth, etc. can also be freely selected, so the material It is recommended that the optimum straight groove be formed by taking into account the type and thickness of the material, the means of adhesion between the materials, the bending radius, etc. Also, it is necessary to provide at least one straight groove on each side of the planned bending line C, and the figure shows one provided on each side,
A plurality of them may be provided if necessary. The shape, size, number, and distance from the planned bending line of the straight grooves may be symmetrical or asymmetrical on the left and right sides of the planned bending line, and the total plate thickness, plate area,
The design may be made according to the bending radius and the position of the bending line (the center or edge of the entire plate width, etc.). The distance between the straight groove closest to the bending line and the bending line may be determined appropriately depending on the situation of the bending part.
Best results were obtained when the distance between the straight groove line and the planned bending line was 1-2 mm.

The means for forming the straight grooves is a press working method. Figure 4 shows straight grooves made by pressing method.
Although this is an example in which P ₁ and P ₂ are formed, the press pressure may also affect the boundary between the surface material 1 and the core material 2, resulting in the formation of a stepped portion 2'. However, it has been confirmed that this does not have any particular adverse effect on the implementation of the present invention.

FIG. 5 is an explanatory diagram showing the state in which the composite material prepared as shown in FIG. ₃ is _bent .
has been compressively deformed and the bending process has been completed, and as is clear from the comparison with Fig. 2, the bending radius can be made small, but even if we carefully examine the surface materials 1 and 3 and the core material 2, No phenomena such as breakage, peeling, or slipping were observed. In addition, in the experimental examples, a plastic core material with thin iron plates laminated on both sides, an aluminum core material with thin iron plates laminated on both sides, a steel plate with plastic plates laminated on both sides, and four layers of these. Things that have 5 layers, etc.
Alternatively, we investigated a simple two-layer structure and a structure in which the plastic plate was replaced with a nonwoven fabric, foam, short fiber aggregate, etc., but no defects such as breakage, peeling, or slippage occurred in either case. For example, Figure 6A
A laminate with the configuration shown in [total thickness: 1.2 mm, aluminum core thickness: 1.0 mm, coating iron foil thickness: 0.1 mm],
In the case where a press groove having the structure and dimensions shown in the figure was formed and the bending process shown in FIG. 6B was performed, the press groove was compressed and lost its groove shape. Compressive deformation was absorbed in the grooves, and the above-mentioned defects such as breakage and peeling were not observed at all.

The reason why such a remarkable effect is produced has not been clarified at this point, but the above effect can be reliably obtained simply by forming at least one parallel straight groove on each side of the planned bending line. Since it has become possible to obtain good bending parts relatively easily without adversely affecting the properties of composite materials, it has become possible to significantly expand the range of application of laminated materials.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing conventional bending procedures, Figures 3 to 5 are examples of the present invention, Figure 3 is a perspective view showing a bending preparation state, and Figure 4 is another example. FIG. 5 is a side view showing the completed bending process, and FIGS. 6A and 6B are explanatory views showing the embodiment. A... Cutting groove, B, P... Straight groove, C...
Bending line.

Claims (1)

[Claims] 1 Form at least one parallel straight groove on the ventral side of the bending part of the laminated material along both sides of the bending line by press working, and bending at the bending line existing between the straight grooves. A method for bending laminated materials characterized by bending.