RU2764696C1 - Wood texture formation method - Google Patents

Abstract

FIELD: woodworking industry.

SUBSTANCE: invention relates to the woodworking industry, in particular to wood impregnation. The method of forming the wood texture includes creating holes in the wood and then impregnating it with a dye under pressure. The holes are burned with a laser beam across the grain of the wood. The hole pattern is determined in accordance with the required texture. Before impregnation, the cross section of the wood is waterproofed. Then the wood is placed in an autoclave, where it is impregnated with a dye under a pressure of 0.3 to 0.8 MPa for 30-300 minutes.

EFFECT: productivity and manufacturability of the process is increased, the deep coloration of difficult-to-impregnated wood is improved, and the consumption of dyes is reduced.

1 cl, 3 dwg

Description

The invention relates to the woodworking industry, in particular to wood impregnation.

It is known that many tree species have a pale wood color and do not have a pronounced texture. One of the options for improving the decorative properties of such wood is its autoclave through impregnation with coloring compositions. The uneven distribution of conductive capillaries in the wood, through which the coloring liquid penetrates during its impregnation, makes it possible to reveal the texture and give the desired color [Kushnirskaya M.Ts., 1973].

However, the texture manifested by such methods is limited to the zones of the annual layer and does not allow the formation of more complex and diverse patterns. In addition, the use of this method is possible only for well-impregnated sapwood, namely, birch and beech. Heartwood and ripe wood species, in accordance with GOST 20022.2-80, are difficult to impregnate. With autoclave impregnation of such wood, it is possible to obtain a penetration depth across the fibers, depending on the species, no more than 2 ... 5 mm. Along the fibers of hard-to-impregnate wood, the impregnating liquid penetrates much better. But satisfactory results can be obtained only for blanks with a length along the fibers of no more than 200 ... 300 mm, which is of no interest for real assortments.

An analysis of patents has shown that there are a number of methods for coloring wood that make it possible to develop the texture of wood SU 54011, SU 164108, SU 1471988 A1, RU 2014994 C1, RU 2375171. low permeability to liquids.

To increase the permeability of hard-to-impregnate wood in local areas, mechanical pricking or drilling holes across the fibers allows [Barake A.M., 1969]. The channels created in this way allow the impregnating liquid to penetrate deep into the assortment and there it is redistributed along and across the fibers for a certain distance. Prick nets (GOST 20022.3) are designed based on the overlap of local impregnated areas. This ensures that the wood assortment has a continuous impregnated zone with a thickness equal to the depth of the punctures.

However, this method not only increases the depth of wood impregnation, but reduces the mechanical properties and worsens the appearance. Therefore, it is quite acceptable for impregnation of structural elements with antiseptics and flame retardants, but is not acceptable for decorative materials.

There is a known method of increasing permeability, described in scientific papers [Md Nazrullslam et al. 2008, 2009, 2011, 2013, 2014]. In these works, the permeability of hard-to-impregnate wood is increased by burning the wood with a laser beam. The diameter of the burnt channels, depending on the thickness of the assortment, is from 0.2 mm.

This method, similar to mechanical pricking, assumes a uniform distribution of burnt areas on the workpiece to ensure uniform penetration of the impregnating solution (antiseptics, flame retardants, polymers) over the volume of the assortment, but does not involve the formation of an artificial wood texture to increase its decorative properties.

The closest in technical essence for the present invention is a method of coloring round timber. This method involves the provision of selective staining of wood due to local end impregnation. The described technology involves drilling cylindrical holes 3-5 cm deep in the ends of round timber, into which metal tips of hoses (pipes) are screwed through which a dye solution is supplied under pressure to the wood. Impregnation is carried out for the entire length of the timber along the fibers (RU 2375171 C2).

The main disadvantages of this method include the low productivity of the process, the impossibility of impregnating wood that is difficult to impregnate, the unpredictable impregnation result, a limited range of possible textures, and high dye consumption.

The objective of the proposed method is to increase the productivity and manufacturability of the process, expand the possibilities for the design of wood texture, ensure the reproducibility of the pattern, provide deep staining of hard-to-impregnate wood, and reduce the consumption of dyes.

The technical result consists in increasing the productivity and manufacturability of the process, through the use of automated serial equipment and technologies, in increasing the permeability of hard-to-impregnate wood due to burning wood with a laser, ensuring reproducibility of the process by working with local areas of wood, ensuring lower dye consumption, by reducing the amount of waste of painted wood during further processing, providing an almost unlimited range of textures, due to the many combinations of placement of holes (cuts) burned by the laser.

A method for forming a wood texture, including creating holes in the wood and then impregnating it with a dye under pressure, according to the invention, the holes (cuts) are burned with a laser beam across the wood fibers, the pattern of the holes (cuts) is determined in accordance with the required texture, before impregnation, the cross section of the wood waterproofing, then the wood is placed in an autoclave, where, under a pressure of 0.3 to 0.8 MPa, it is impregnated with dye for 30-300 minutes.

To form the texture of wood by the proposed method on the side surface of blanks of coniferous or hardwood, using a laser beam, holes with a diameter of 0.1 mm or short cuts up to 3 mm are burned. The distance between the holes (cuts) along the wood fibers is taken depending on the permeability of the wood and varies from 5 mm (hardly impregnated wood) to 200 mm (moderately and easily impregnated wood). The distance between the holes (cuts) across the wood fibers is taken in accordance with the required texture pattern, but not less than 2 mm (examples of local impregnation schemes are shown in figures 1, 2, 3). The holes (cuts) burnt in the wood can be both through and to any given depth in accordance with the required texture pattern or staining depth.

After laser perforation, the workpieces are placed in an autoclave, where, at an overpressure of 0.3 to 0.8 MPa, they are impregnated with a coloring composition for 30–300 minutes. The regime parameters of impregnation are selected depending on the permeability of the wood. Before impregnation, the ends of the blanks are waterproofed in order to prevent the penetration of the impregnating solution along the fibers through the cross section of the assortments.

In the process of impregnation, the impregnating solution penetrates into the workpiece, primarily through holes (cuts) burned in the wood, and then it is redistributed mainly along the fibers and slightly across the fibers. At the same time, due to the location of the burnt areas in the workpiece, it is possible to form an artificial wood texture due to local staining.

After impregnation, the blanks, depending on the purpose, undergo chamber drying and mechanical processing by sawing, planing, milling, turning, etc.

An example of the proposed method

1. Wooden blanks of the required dimensions, taking into account allowances for shrinkage and processing using a loading device, are placed on a belt conveyor, which moves them to a CNC portal laser machine;

2. As the workpieces move through the working area of the laser installation, holes (cuts) are burned in them according to a programmed scheme;

3. After laser perforation, the ends of the blanks are waterproofed with a sealant;

4. Workpieces with waterproofed ends are placed in packages, which are transferred to rail carts with the help of a loading device and rolled into an autoclave;

5. In the autoclave, the blanks are impregnated with a coloring composition at an overpressure of 0.3 to 0.8 MPa for 30-300 minutes;

6. After impregnation, the workpieces are transferred to a batch drying chamber, where they are dried to the required moisture content;

7. To develop the texture of the blanks and bring them to the specified dimensions, the dried blanks are processed in a four-sided longitudinal milling machine;

8. After milling, the resulting products are placed in transport packages and packaged.

This method increases the productivity and manufacturability of the process, through the use of automated serial equipment and technologies, provides deep staining of hard-to-impregnate wood, by burning wood with a laser, reduces the consumption of dyes, by reducing the amount of waste of painted wood during further processing. The method makes it possible to expand the possibilities for the design of wood texture, to ensure the reproducibility of the pattern, due to the many combinations of placement of laser-burnt holes (cuts) and work with local areas of wood.

The proposed method makes it possible to obtain from wood species in its natural form lumber or sawn veneer with high decorative properties that do not have a bright color and expressive texture. These materials can be successfully used in the production of furniture, floor coverings and finishing materials, interior items, art objects.

Claims (1)

A method for forming a wood texture, including creating holes in the wood and then impregnating it with a dye under pressure, characterized in that the holes (cuts) are burned with a laser beam across the wood fibers, the pattern of holes (cuts) is determined in accordance with the required texture, before impregnation, the cross section wood is waterproofed, then the wood is placed in an autoclave, where, under a pressure of 0.3 to 0.8 MPa, it is impregnated with dye for 30-300 minutes.

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