The Technical Process of Solid Wood Bending(Part 2)

(1) Ordinary solid wood bending process:

The thickness of the workpiece is relatively thin, within 25mm, and the radius of curvature is larger, above 450mm. It can be bent directly on a multi-layer hot press, but be careful to strike while the iron is hot and bend in high temperature and soft state. This method has a high output and simple equipment investment, but the product shape stability is poor. Our company provides high-stability RF hot press machine.

(2) Italian solid wood bending process:

It is divided into two steps: pre-bending and bending. Clamp both ends of the wood longitudinally so that it does not extend, the middle bending point of the support is not suspended to prevent breakage, and the bending part is initially dehydrated by high-frequency heating. In the later stage, the entire part will be dried with high frequency until the moisture content reaches 8%. The radius of curvature of this process can reach more than 300mm, and the drying is even, the time is short, and the efficiency is high.

(3) European and Danish solid wood bending process:

The core technology is the compression process. High requirements for wood, artificial wood is best, tree trunks less than three meters, can not choose new wood or surface wood, choose two surface wood, diameter cut wood, naturally placed non-kiln dried. The wood compressor is used to compress the wood longitudinally so that the fibers will wrinkle and will not break when bent. The advantage is that it can be bent in multiple directions, and it can be manually bent after being placed for a period of time without being bent immediately.

4. Drying stereotypes

Drying stereotypes is to make the moisture content reach the requirement of lignin stability. In the bending drying setting, the bending wood can be completely set after being dried for 30h and 12h at 160℃ and 180℃ respectively. But high-frequency heating and drying is more uniform by comparison.

The methods of controlling rebound mainly include physical methods and chemical methods. The physical method is to make the bending angle 1〫-2〫 larger than the design angle during bending. The chemical method is to plasticize with styrene and polyvinyl alcohol, or apply polyurethane coating and impregnate phenolic resin.

5. Processing of curved parts

After bending, the machining surface or machining datum of the bent part is no longer accurate. To achieve high-quality requirements, it must be reworked and the datum and profile machining must be re-determined.

After the bending parts are processed, the bending quality can be judged according to whether the parts are discolored, broken, or spring back. To achieve excellent bentwood quality, there must be no mistakes in each of the above steps. As a natural product, wood is not exactly the same, so success or failure can be determined by grasping the details!

The information is provided by solid wood bending machine manufacturer.