Comparison of Production Technology and Equipment of Plywood between China and Europe (I)
At present, the main raw materials of plywood in China are fast-growing poplar in the north and fast-growing Eucalyptus in the south. Plantation logs generally have poor raw materials, many shortcomings such as scarring, and high density variability. These characteristics have a primary impact on the production of veneer commodities such as plywood.
Although China’s plywood industry has been developing for many years, it develops slowly, mainly because of backward processing technology and production equipment. The vast majority of plywood companies are labor-intensive production. Although they can improve the utilization rate of wood, the quality is difficult to improve, the value of commodities is low and the income is low, which seriously restricts the development of China’s plywood industry. It is inconsistent with the position of China’s major international plywood producers. It is urgent to select leading processing technology and production equipment to transform and upgrade.
1. Production Technology and Application of Plywood in China and Europe
1.1 Production Technology
Chinese plywood manufacturing technology differs from European companies as a whole in that:
Technically, the production of European plywood has realized the whole core board, while the domestic production of the core board mostly consists of two-piece, three-piece or even four-piece structure. Although the processing and application of small-scale veneer can improve the yield of logs, it is difficult to ensure the quality of veneer.
Equipped with, European companies for the initiative, intelligent assembly line work, the domestic plywood production equipment initiative is low, mainly manual workshop operation.
The difference of the primary section of the processing industrial process:
(1) Log peeling
Over the past few years, the technical functions of rotary cutting equipment in domestic plywood companies have been continuously improved, and the appearance quality and thickness uniformity of veneers have been improved. However, there is still room for improvement in overall equipment durability, initiative and quality control.
Raute Peeling Line series production lines are mostly used by European plywood companies, which can select and configure equipment according to output value, processing accuracy and raw materials and diameter requirements for processing logs. In addition, they can actively check the quality defects of veneer, such as moisture content, appearance knots and scars, so as to effectively control the quality of wet veneer.
(2) Veneer dryness
Dry technology has the primary influence on the quality of follow-up sections and plywood. Most small and medium-sized companies in China still use natural sun drying as the main drying method. They can not control the final moisture content and uniformity of veneers, nor can they ensure the drying power and output value, resulting in energy waste and uneven quality of follow-up sizing, embryo formation, hot pressing and other technical links, affecting the quality of final products.
European companies have chosen leading veneer dryers for drying, such as Raute Dragon Dryer, which can effectively and accurately control the temperature and humidity of the drying room and maximize the use of heat energy. In addition, water content, moisture distribution and other inspection techniques are used to ensure that all the boring processes are carried out by closed-loop control.
In addition, the active grading system rationally allocates different levels of veneers, facilitates subsequent sections and improves production and management power.
(3) Veneer repair
As a useful method to improve veneer grade and plywood quality, veneer repair technology is widely used in domestic plywood production companies. But most companies choose manual repair. Although waste materials and low-grade veneers can be used effectively, they consume more labor, and the repair effect is not good, and the veneer repair thickness is limited. Domestic equipment companies have developed repair equipment in recent years, but the degree of equipment initiative is low, and still need more manual operation. With the use of artificial forest logs, veneers show more shortcomings such as holes and scars, and the repair quantity increases sharply, while labor costs continue to rise, making the repair section become the bottleneck of many small Plywood Companies in China.
European companies have become sophisticated in repairing technology, using leading all-active multi-head video to locate the production line. For example, Raute P2 line, the repair time is only 0.5s, and the service life of the repair head is up to 50 years.