Key equipment and technology for the production of three-layer solid wood composite flooring

Three-layer solid wood composite flooring originated in Europe and developed to China in the 1990s. Because it overcomes the shortcomings of wooden flooring, it has become a fashionable product in Europe and is gradually accepted by domestic consumers.

What is three-layer parquet

The three-layer solid wood composite floor is made of slats treated with paper thread or glue thread as the core board, with the sawn or sliced veneer of precious wood as the panel, and the rotary cut sheet of fast-growing poplar, eucalyptus, etc. The board is a bottom board, a new type of floor processed by pressing and mortising and milling.

The wood fibers of the adjacent layers of the three-layer composite floor are perpendicular to each other, which overcomes the anisotropy of natural wood, and the core board is made of narrow wood strips that have been tensed, which greatly reduces the internal stress of natural wood.

This type of floor usually has the following characteristics:

       1. Maintain the natural wood texture of the solid wood floor, simple and beautiful, elegant and generous;

       2. Comfortable foot feeling and good sound insulation effect;

       3. Dimensional stability, not easy to deform, not easy to crack and curl;

       4. Improve the utilization rate of precious wood, make the best use of the material, and make the best use of the excellent material;

       5. The adjacent wood textures are arranged staggered to improve the strength of splitting resistance. Therefore, the three-layer solid wood composite floor can be processed into a lock and tenon shape, which has the advantages of easy paving of the lock and tenon floor.

Three-layer solid wood composite floor production process

The production process of three-layer solid wood composite flooring can be summarized as: wood drying treatment---face veneer processing---core board processing-back board processing---gluing, blank assembly---hot pressing---curing---surface coating process.

Wood drying treatment

Because the moisture content of wood directly affects the stability of wood processing products, in order to ensure the quality of the three-layer solid wood composite flooring product, the wood raw materials used to process the product must be dried before production to fully control the moisture content and release stress .

When wood is dried, the corresponding drying process should be formulated according to different tree species and initial moisture content. Wood drying should be achieved by drying kilns, and dried wood should be treated with health preservation.

Face veneer processing

The panel of the three-layer solid wood composite floor is usually 3-4mm, which is an important part of the three-layer solid wood composite floor. The material and processing accuracy of the panel directly affect the quality of the product.

The front panel used to be ABCD grade, which means there is no scarring, but the end is cracked. In the past few years, there has been a DE grade, which means that there is scarring and cracking. Such a board needs artificial repair. The more natural, then putty repaired.

Core board processing

The core layer of the three-layer solid wood composite floor is usually about 9 mm. The raw materials used are usually fast-growing woods, such as pine wood and poplar wood. When selecting materials, try to avoid defects such as dead knots, decay, blunt edges, and cracks. The gaps are consistent with each other.

Backplane processing

The backboard of the three-layer solid wood composite floor is usually about 2 mm. The raw materials used are usually fast-growing wood, such as pine wood and poplar wood. Generally, high-quality veneers are used as a whole. The backplane processing usually adopts the peeling process.

Glue, blank assembly

According to the process requirements of different manufacturers, the panel, core board and back board are glued and assembled. The adhesive used for gluing must be environmentally friendly and meet the requirements of national standards. The gluing should be uniform and the amount of glue should meet the requirements of gluing quality.

Hot press

The assembled slabs are formed by hot pressing according to the hot pressing process requirements by a hot press. The hot pressing parameters such as temperature, time and pressure must be adapted to the hot pressing process to ensure product quality requirements.

Surface finishing process

Paint is an indispensable surface treatment of the floor, which aims to improve the surface decoration effect, keep the floor surface smooth and clean, and protect the wood surface to ensure the use requirements.

Key equipment for three-layer solid wood composite flooring

Good equipment can get twice the result with half the effort. For the production of three-layer solid wood composite flooring, the choice of equipment is very important.

Table splitting equipment

The sliced veneer used for the surface board material has always been the first choice for the surface board of the solid wood composite floor, because there is no sawing wood loss in the cutting, which improves the utilization efficiency of precious wood.

There are three veneer sawing methods: circular saw, band saw and gang saw. Under normal circumstances, the circular saw cutting method is limited by the diameter of the saw blade, which is suitable for the production of "three pieces" of the table; the band saw and gang saw cutting method are suitable for the "single frame" of the table. Floor production. Regardless of the sawing method, a thin sawing road is used as a design prerequisite.

Pressing equipment

Three-layer solid wood composite flooring is a new type of flooring. The representative pressing equipment used in the existing three-layer solid wood composite floor manufacturers in China has the following two types:

European imported equipment represented by single-layer or multi-layer automatic feeding and conveying presses: its advantages are reasonable process layout and high degree of automation; its disadvantages are large equipment investment and low output.

The production equipment of domestic pre-press + multi-layer hot press: the advantages are low equipment investment and large output; but the degree of automation is lower than that of imported equipment.

Slicing and surface sanding equipment

The slab of the three-layer solid wood composite floor is pressed and balanced and then processed into pieces, and the whole floor blank of multiple floors is cut into a single floor blank.

Generally, multiple circular saws are used for segmentation, and the spacing of the saw blades = the width of the finished floor + the machining allowance of the tenon and the tenon. Smaller companies can also use a sliding table saw for segmentation processing. After slicing, the blank is surface sanded or double-sided sanding. The accuracy and sanding effect of the sanding machine have a very important influence on the surface quality of the finished floor.

Floor coating

The floor paint process has a great relationship with the tree species of the table board, which process cannot be used mechanically. For example, for broad-leaved materials with large tube holes, the first filling of putty can not completely cover the tube holes, and secondary filling is required; for diffuse-porous materials with fine tube holes, one filling of putty can completely cover the tube holes.

Tenon, tenon and groove processing equipment

The three-layer solid wood composite floor blanks have been sanded and even surface painted before processing the tenon and groove. Therefore, the upper and lower surfaces do not need to be cut, only the tenon and groove are processed.

Currently, there are two types of tenon on the market-flat tenon and lock tenon. Regardless of the tenon shape, the cutter and the inclination angle of the cutter shaft must be correctly equipped according to the characteristics of the wood texture and core board.

Three-layer solid wood composite floor technology key

The following technical keys involved in the production process of three-layer solid wood composite flooring are only for selective reference in the industry:

About drying

After palletizing the logs into specifications, they are naturally dried in the board yard for more than 3 months to reduce the moisture content to about 15%, and at the same time minimize the internal stress of the wood.

The sawn timber is dried by a drying kiln with advanced technology and high control precision. After the kiln, the difference in moisture content between the woods should not exceed 2.5%, and the stress index should not exceed 2%, which is higher than the national first-level drying quality standard.

In the balance adjustment room where the environment, temperature and humidity are relatively stable, balance the dried wood for more than 7 days to further eliminate the internal stress of the wood, and make the moisture content between the wood more uniform, and ensure the dimensional stability of the wood during use .

About billet assembly and hot pressing

The raw material of the horizontal core board backplane is divided into the core board and the core board is assembled. After the proper gluing process is completed, the panel, the core board and the bottom plate are assembled and hot pressed.

When the core plate is split, the thickness tolerance of the core plate should be controlled within ±0.1mm; during the hot pressing, high-quality imported urea-formaldehyde resin glue and strictly controlled hot pressing time, hot pressing temperature and hot pressing pressure are It is the key to ensure the bonding strength between the core board and the panel and the bottom board and control the amount of formaldehyde emission.

When assembling blanks, the grain directions of the surface, core and bottom plate are crisscrossed, which overcomes the shortcomings of the anisotropy of the wood itself, and effectively controls the dimensional stability of the finished floor. At the same time, pay attention to the reasonable combination of water content of the table, core and bottom plate to ensure the flatness of the finished floor.

About size control

After hot pressing, the floor blank is finely sanded with a sanding machine for several times, and then grooves and tenons are cut around. The thickness tolerance of the finished floor after sanding is controlled within ±0.2mm, and the sanded surface is used as the reference surface for opening the surrounding grooves.

After the high-precision slotting and tenoning equipment is processed, the length tolerance of the finished floor is controlled within ±1mm, the width tolerance is controlled within ±0.1mm, the straight angle is less than 0.20mm, and the edge straightness does not exceed 0.30mm/m. The finished floor assembly is no more than 0.20mm away from the seam, and the splicing height difference is no more than 0.15mm, thus ensuring the quality of floor paving and use.