JPS6245803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting raw wood for veneer lace, and its purpose is to ensure that the radial tissue (also known as medullary rays) of the cut veneer is approximately equal to the surface of the veneer. By obtaining a veneer with a right angle, it is possible to eliminate the loss of the veneer after drying and to produce high-quality plywood with no uneven adhesion.

The conventional cutting method for veneer lace is
For example, use a projector to project multiple circles onto the end surface of the log so that approximately the center of the end surface of the log becomes the center of rotation during turning, find the center on the end surface of the log, and then hold the center with a chuck. , Chucking has been carried out so that the center of the end face is the center of rotation as much as possible. However, wood has a radial structure that suppresses radial deformation of the wood, extending radially from the center of the annual ring (pith) toward the circumference, and unless the center of the butt surface and the center of the annual ring coincide, According to the conventional cutting method, most of the radiation structure of the cut veneer is necessarily inclined with respect to the surface of the veneer. The strength of the veneer in the area where the radial structure is inclined in this way is weak in the thickness direction of the veneer, and is affected by the pressing force in the thickness direction, such as hot plate pressing during drying and cold pressing or hot pressing during the pressing process. In many cases, they become deformed. Therefore, conventional methods have been to anticipate this thickness loss in advance and cut it a little thicker, but it is also possible to cut the veneer in the direction of the fibers of the veneer or in the direction orthogonal to the fiber direction. Unlike girders and cross-leafs, it is difficult to compensate for the thickness of the veneer, and it is also a cause of poor adhesion due to uneven adhesive application and uneven compression.

In order to solve these problems in the plywood manufacturing process, the present invention holds the center of the annual ring, which is the starting point of the radial structure, with a chuck and turns it, so that the radial structure is almost perpendicular to the surface of the veneer. The aim is to produce plywood of similar quality with less wear and uneven adhesion.

An example of implementation of the present invention will be described below with reference to the drawings.

In a log A where the growth ring center 3 existing on the end surface 1 of the log does not coincide with the center 4 of the end surface, the growth ring center 3 is held with a veneer lace chuck (not shown), and the rotation center of the log during cutting. Turning is performed so that the center of the tree ring is the center 3 of the annual ring.

At this time, the material near the center of the tree ring 3 is extremely fragile, and there are often cavities due to insect attack or rot, so it may not be possible to hold it directly with the chuck, but in such cases, a piece of wood can be driven in. There is no problem if you hold it in place by holding it in place or using a batten. Note that 2 in the figure is a radial tissue extending in the circumferential direction around the annual ring center 3, and a to g indicate individual radial tissues.

When turning is performed using the rotary race with the annual ring center 3 as the center of rotation as described above, the cutting trajectory of the knife becomes the chain double-dot line X in the figure, and the states of the radial tissues a to g in the cut veneer 5 are As shown in FIG. 2, the direction is approximately perpendicular to the surface of the veneer 5 (thickness direction). When the same raw wood A is cut using the conventional cutting method, the cutting trajectory drawn by the knife shows a two-dot chain line Y, and the state of the radiation structures a to g in the cut veneer 6 is centered at d as shown in Fig. 3. It can be seen that it slopes inward towards both ends. In this way, the veneer 6 with different states of the radiation structures a to g has a difference in the stress of each part of the veneer in response to the pressure applied in the thickness direction.
For example, distortion occurs as shown in FIG.
That is, the part where the radiation structure is perpendicular to the surface of the veneer (Fig. 3 d) is relatively strong against the pressing force in the thickness direction, but the radiation structure is inclined with respect to the surface of the veneer. As a result, it becomes weaker and compressively deforms.

On the other hand, in the veneer 5 cut according to the present invention, the radiation structures a to g are all in a direction substantially perpendicular to the surface of the veneer, so it is relatively strong against pressing force in the thickness direction. Since the stress in each part of the board is equalized, there is less distortion in the veneer. Therefore, there is no compression (scale) or distortion caused by hot plate pressing, making it possible to apply the adhesive uniformly, and also eliminating distortion during the pressing process, making it possible to manufacture high-quality plywood without defective adhesion.

Furthermore, as mentioned above, when cutting logs that have rot or insect damage near the center of the annual ring (pith), the area that cannot be made into an effective veneer using conventional cutting methods is cut with a knife, and conversely, it becomes an effective veneer. Previously, the center of the wood end (wood part) obtained was discarded as a core, but according to the present invention, the center of the tree ring (pith) can be cored, so the wood part can be used effectively. This also leads to the conservation of wood resources.

As described above, according to the present invention, a veneer that is strong against pressing force in the thickness direction of the veneer can be manufactured, and cutting that is suitable for the material of each part of the wood is possible, and an improvement in yield can be expected. The contribution to the plywood industry is extremely large.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the end surface of a log where the center of the annual ring and the center of the end surface do not coincide, and Fig. 2 is an explanatory diagram showing the internal structure of a veneer cut by the cutting method according to the present invention. 3 are explanatory diagrams showing the internal structure of a veneer cut by a conventional cutting method, and FIG. 4 is an explanatory diagram showing a state in which the veneer in FIG. 3 is compressed and deformed. A...Log where the center of the annual ring and the center of the butt end surface do not match, 1...The end surface of log A, 2(a-g)...radial tissue, 3...center of the annual ring, 4...center of the butt end surface, 5...cutting trajectory X 6... A veneer obtained by cutting path Y.

Claims (1)

[Claims] 1 When a log is held by a chuck attached to the main shaft of the veneer lace, the center of the annual ring of the log becomes the center of rotation, unless the center of the end surface of the log coincides with the center of the tree's annual ring. A method for cutting logs in veneer lace, which is characterized by holding and cutting as shown in FIG.