Views:2 Author:Site Editor Publish Time: 2019-09-06 Origin:Site
Due to the steady development of concrete construction in recent years, the sheet system has become a very important place. Where should I use plywood? How is it produced? Below I will tell you the production of one of the plywood-film faced plywood.
Film faced plywood background
Film faced plywood production process
The first machine that converted wood into veneers and then into plywood was patented as early as the 18th century. It is worth pointing out that almost all inventors are related to Russia to some extent. This technology has not changed since its inception, and although the machine has been modernized, it is now fully automated. This reduces the need for manual labor during the production phase, thereby improving the quality of the final product plywood.
Film faced plywood's production process requires careful selection and preparation of raw materials. First, choose the right size wood. Some custom sizes are another matter.
The main stage of preparation is to soak the raw materials. It is in a special swimming pool (open or covered) for 24 hours. In summer, the indoor temperature is maintained at 35 to 40 degrees, and in winter it is maintained at 40 to 45 degrees. In order to improve the quality of the film faced plywood, it is important to maintain the proper temperature and proper time conditions at this stage.
The softened logs are transferred to the peeling and cutting department. The method of peeling is as follows: The special knife of the peeling machine scratches the bark and removes it in a spiral manner. The removed bark is not only used to heat the plants themselves, but also to heat adjacent buildings or even entire villages. The exfoliated logs (almost no bark) then pass through a metal detector. This helps detect metal impurities in the wood, such as nails, wires, etc., which can damage the equipment. When metal is detected, the signal is sent to the machine's control panel, the conveyor is stopped, and the metal is removed by the operator.
The next step is to strip the veneer on a special machine where a thin continuous veneer is stripped from the prepared logs. The thinner the veneer, the more film faced plywood layers of a certain thickness. The more layers, the stronger the film faced plywood. In the stripping stage, the quality of the veneer is controlled: factors such as the thickness of the veneer are sampled every day and compared with the standard. Then adjust the settings of the peeler based on these results.
The sliced veneer is then dried. In the dryer, hot air is blown onto the board. Up to 90% of the moisture is removed from the wood in 8-10 minutes. After drying, the veneers are stacked on a tray or conveyor. After drying, the veneers are graded by various properties, including knots, cracks, and the like.
To get a piece of finished plywood, several veneers must be glued together. The fibers in each layer of the veneer are perpendicular to each other, giving the finished product a strong strength. The finished board resists any form of deformation. This property makes plywood an ideal material for stencil systems in concrete applications.
The cold preloading of the plywood is carried out prior to hot pressing in order to obtain a high quality package for transport and loading into the hot press. Under the pressure of 1-1.5MPa, the cold pre-pressing takes about 5-10 minutes. On this basis, the plywood is placed on the hot press frame and finally bonded at a pressure of 120-130 ° C and 1.2-1.8 MPa. .
After pressing, cut all four sides of the adhesive tape to the size required by the customer. After that, the plywood is ground on the machine to make it smooth and uniform in thickness. The plywood is then fed through different sizes of abrasive belts. The plywood is then sorted again according to the appearance of the plywood: the operator evaluates the quality of the plywood.
In the final stage, a layer of film is applied to both sides of the plywood. The plywood is then loaded into a multi-open press. The pressing time depends on the density of the film, the thickness of the plywood and the finish (smooth or mesh). The film provides additional protection to the plywood from water and mechanical damage as well as corrosive environments. Thus, ordinary "white" plywood becomes a plywood for coating or film surface.
Next, the film faced plywood is sent to the cutting line where it is cut to the specified size. The finished product is then sorted and packaged according to the appearance and geometric parameters of the product. After the sorting is completed, these plywoods are sent to the spray booth. Here, a special latex paint with acrylic base is applied to the end sheets. This coating protects the ply from moisture and expansion.
As we have seen, the process of film faced plywood is quite complicated. The quality requirements of the final product are strictly in accordance with the technical process at every stage of production. In fact, the production of the laminated board and the fancy board are equally rigorous.