JP2001198905A - Method for press-forming wooden thin plate and press forming thin plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent crack and strain from being generated when a wooden thin plate is to be press-formed. SOLUTION: Wood is sliced to form, for example, a 0.5 mm thick thin plate 10, and pin holes 11 are opened on the whole surface of the thin plate by using a pin hole-opening machine. For the pin hole-opening machine, needles 13 are densely planted on an under face of a pressing plate 12 moving vertically. When the pressing plate 12 descends, the needles 13 are stuck into the thin plate 10, and the pin holes 11 are opened. The thin plate on which the pin holes are opened. The thin plate on which the pin holes are opened thus is boiled with water for about 5 min and softened. Inserted of boiling, it may be warmed by steam. The thin plate which has absorbed water by boiling is pressed with a pressing machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for press-forming a thin wooden sheet (wood) to form, for example, a tray and a thin sheet for press-forming.

[0002]

2. Description of the Related Art Plastic molded trays are widely used in supermarkets and the like in order to arrange and sell foods. Such a plastic tray is advantageous in that it can be easily processed into various shapes and that it can be manufactured at low cost. However, disposal of a used tray is a problem. When incinerated, it emits toxic gases and does not decompose forever, even when buried in the soil. That being said, if you try to recycle, it costs a lot to collect.

Therefore, it is conceivable to make a tray by pressing a thin sheet of wood, which is a natural material, instead of such a plastic. Such a thin wooden tray is advantageous because no harmful gas is emitted even if it is incinerated after use, and if it is buried in the ground, it can be eliminated in a short time by the action of bacteria, which is convenient. Not only that, you can enjoy wood grain and wood incense, and it has high added value.

However, wood has a strong anisotropy unlike plastic and metal, and has a problem that a thin plate is easily broken when pressed and deformed after being formed.
In order to prevent cracking at the time of pressing, it is effective to boil the thin plate immediately with hot water or to immerse the thin plate in caustic soda to soften the thin plate. Further, in order to prevent deformation after pressing, it is also effective to apply a resin to the surface of the thin plate and to cure it by heat at the time of pressing. However, even if such measures are taken, if the depth of the tray is increased, cracking and deformation are inevitable. For this reason, there is a conventional tray formed by laminating several thin plates with their fiber directions alternately stacked and bonded. Further, there is also a type in which a corner of a thin plate before molding is cut diagonally, and the corner is adhered with an adhesive at the time of molding. Such a material has less cracks and irregularities like a plywood, but a laminated material has a high manufacturing cost, and in both cases, the adhesive may impair the safety of food.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent cracks from being generated when press-forming a thin wooden board, and to prevent deviation after forming.

[0006]

In order to solve this problem, according to the present invention, a large number of needle holes are formed in a thin wooden plate before press forming with a planar spread. When a large number of needle holes are made in this manner, the wood fibers are cut short, so that the directionality is eased and the fibers are easily bent in a direction perpendicular to the fibers. For this reason, even if it press-molds, it becomes difficult to generate a crack. Also, deformation after molding is reduced.

[0007] The thin plate used for press molding is obtained by cutting wood (for example, cedar, red pine, etc.) to a thickness of about 0.1 to 2.0 mm. Needle hole in this, make the diameter as small as possible,
It is preferable to open it densely. Needle hole diameter is 0.05-0.5m
m, the density is desirably about 50 to 1000 pieces per 1 cm ² . The needle hole may or may not penetrate the sheet. The denser the needle holes, the easier it is to bend. However, if the holes are too dense, the distance between the needle holes decreases, and the holes easily break along the fiber direction of the wood. Therefore, it is preferable that the needle holes have a large interval in the direction along the fibers of the thin plate and a small interval in the direction perpendicular to the fibers. Also, if the needle holes are regularly drilled in the vertical and horizontal directions, the needle holes are aligned and are easily broken. Therefore, it is preferable that the needle holes are randomly arranged as a whole. In addition, the thin plate used for press molding may not only make a needle hole but also make a diagonal cut in a corner as in the related art. This way, even deep trays are more difficult to break.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Wood is sliced to, for example, 0.5 mm
A thin sheet 10 is formed, and as shown in FIG.
A needle hole 11 is randomly formed on the entire surface using a punch.
The drilling machine is a plant in which needles (or steel wires) 13 are densely and randomly planted on the lower surface of a pressing plate 12 which moves up and down, and when the pressing plate 12 descends, the needles 13 pierce the thin plate 10 to insert the needle holes 11. There is.

The thin plate having the needle holes thus formed is softened by boiling with water for about 5 minutes. Instead of boiling, steaming may be used.

[0010] The thin plate, which has been boiled and absorbed, is placed on a press. As shown in FIG. 3, the press machine includes a female die 15 fixed to a machine base and a male die 16 attached to the tip of a rod 17 of a pressing cylinder. The female and male molds each incorporate an electric heater, which reduces the mold surface temperature by 100%.
Keep at ~ 200 ° C. The thin plate 10 is placed on the female mold 15 (FIG. 3).
(Left figure), the pressing cylinder 17 is extended and the male die 16 is turned into the female die 1
Press into 5 (middle figure). Press pressure is 3000 ~
Take about 5000kg. In this way, after a few seconds, the moisture contained in the thin plate evaporates and is molded, and when the mold is opened, the molded thin plate tray 19 is obtained (right figure). FIG. 1 shows a perspective view of the tray 19.

In the above-described embodiment, the drilling is performed after the boiling step, but may be performed before the boiling step.

FIG. 4 shows another punching machine, in which a large number of needles 22 are implanted on the peripheral surface of one roller 20 of two rollers driven in rotation, and The surface is covered with a rubber cloth 23. When the thin plate 10 is inserted between the two rollers, the thin plate is sent out from the opposite side so as to be sandwiched between the rollers. When the thin plate 10 is sandwiched between the rollers, a needle hole 11 is formed on the entire surface of the thin plate by the needle 22 of the roller.

[Brief description of the drawings]

FIG. 1 is a perspective view of a tray formed from a thin wooden plate.

FIG. 2 is an explanatory view of a drilling machine.

FIG. 3 is a conceptual diagram of a pressing step.

FIG. 4 is an explanatory view of a roller-type drilling machine.

[Explanation of symbols]

 10 Wooden sheet 11 Needle hole 19 Tray

Claims (4)

[Claims] 1. A method for press-forming a thin wooden board, wherein a number of needle holes are formed in the thin board prior to press-forming the thin wood board. 2. The method of press-forming a thin wooden plate according to claim 1, wherein said needle holes are formed in a random arrangement as a whole. 3. A thin plate for press forming in which countless needle holes are formed in a thin plate of wood. 4. The thin plate for press forming according to claim 3, wherein the needle holes are formed in a random arrangement as a whole.