Technical field

The present disclosure relates to a method for producing a board product, the method comprising: providing a base board, producing one or more sheets of veneer, and attaching the one or more sheets of veneer to the base board.

Background

One example of a method for producing veneer for board products is indicated in US- 5979524-A. In that document there is disclosed cutting veneer from a flitch using a knife. A reciprocating movement causes the knife to peel off veneer layers

A general problem in this technical field is how to provide a more efficient process with improved yield.

Summary

One object of the present disclosure is therefore to provide a method for producing a board with improved efficiency and/or yield. This object is achieved by means of a method as defined in claim 1 . More particularly, in a method of the initially mentioned kind, the sheets of veneer are produced by drying a flitch, and sawing the flitch into veneer sheets having a thickness tv in the range 0.5-1 .7 mm. Subsequently, the sheets of veneer are glued to the base board.

With this method, the veneer production becomes more robust. For instance, attempting to cut a piece of flitch comprising a large knot with a knife will build excessive tensions in the flitch material, and potentially cutting errors in or close to the knot, for instance diverging thickness, or the knot simply falling out, leaving a hole in the veneer. Instead, sawing a sheet will simply cut the knot off together with the surrounding material. The thickness range indicated facilitates producing a stable veneer product. This results in a board produced efficiently with high yield, i.e. a low percentage of sheets need be discarded, and consequently, the cost may be lower.

The sawing may provide veneer sheets having a thickness in the range 0.7-1.5 mm, and more preferably in the range 0.8-1 .3 mm. However, 0.3-1.3 mm or 0.5-1.3 mm are also considered useful veneer sawing thickness ranges. This results in an even more improved yield. Preferably, the dried flitch may have a moisture content of 6-14 %, more preferred within the range 8-12%.

The base board may be of a type selected in a group comprising: particle boards, HDF boards, MDF boards, OSB (boards), and hollow boards.

A plurality of veneer sheets may be attached side by side on the base board. If so, an interface between two adjacent veneer sheets may optionally be depressed towards the base board to form a valley extending between the two adjacent veneer sheets to provide a depth effect. The depressing may be made by a depressing rolling tool arranged to roll along the interface between the adjacent veneers and form the depression.

Such a step of depressing an interface between two adjacent veneer sheets may occur after the veneer sheets have been glued to the base board.

The plurality of veneer sheets may be attached to each other to form a compound veneer sheet prior to gluing the veneer sheets to the base board and said step of gluing said one or more sheets of veneer to the base board may involve gluing the compound veneer sheet to the base board.

The base board may have a first and a second flat surface, wherein both flat surfaces are provided with veneer sheets.

Typically, the base board has a thickness tb of 5-30 mm.

The present disclosure also considers a corresponding board product. Such a product comprises a base board and a veneer layer attached to the base board, where the veneer comprising sawn sheets having a thickness in the range 0.5-1.7 mm, which are glued to the base board. The product may be varied in accordance with the above-defined method.

Brief description of the drawings

Figs 1 -3 illustrate sawing of a flitch into veneer sheets.

Figs 4-6 illustrate preparation of veneer sheets and attaching of veneer sheets to a base board.

Fig 7 illustrates processing of interfaces between veneer sheets. Fig 8 illustrates one example of a furniture product where a board product may be used.

Detailed description

The present disclosure relates to furniture board products comprising veneer. Veneer has been used for centuries to produce furniture with high esthetical qualities.

Further, compared to solid wood, a veneer product has potential for structural- and cost advantages, while still providing a beautiful wood patterned surface.

Figs 1 -3 illustrate schematically the production of veneer sheets from a flitch 1 according to the present disclosure. By a flitch is here meant a longitudinal section of a log.

The flitch 1 is dried, typically to a moisture content of around 6-14 % moisture content, preferably 8-12 % moisture content, measured according to EN 13183- 1 :2002, after being produced from a raw log (not shown). Typically, the flitch may then be stored at a relative humidity of 30-60 % in order to provide a flitch suitable for the further production steps, although a wide range of variations are possible to provide a useful result. In any case, this is in contrast to traditional production of veneer where usually the raw material is watered in order to facilitate production.

The flitch may comprise of any desired wood species such as oak, maple, birch, pine, beech, walnut, spruce, eucalyptus, larch, etc.

In the present disclosure, a veneer sheet 3 is provided by sawing the flitch 1 into sheets with a thickness in the range of 0.5-1.7 mm, 0.7-1.5 mm being an even more preferred range, still more preferably 0.8-1.3 mm. 0.3-1.3 mm or 0.5-1.3 mm are also considered useful veneer sawing thickness ranges. The sawing may be carried out with the cut propagating in the direction of the wood fibers, although variations are possible. In the illustrated case, a bandsaw 5 is used, although for instance a saw with a reciprocating blade may be considered as well. In any case, using sawing in this context is contrasting to conventional veneer production where typically a knife or a lathe is used to cut sheets of veneer, and this cutting takes place usually with a cut propagating in a direction perpendicular with the direction of the wood fibers.

A feeding arrangement, such as the illustrated rollers 7, may be used to feed the flitch 1 to the bandsaw 5, or the like. Thanks to the use of sawing, even wood with relatively large knots and other irregularities can be used as a flitch. This is in contrast with traditional veneer production where usually specially selected wood with few knots and other irregularities is selected for veneer production in order to provide a useful yield.

Otherwise, tensions built when attempting to cut through large knots may result in deficient veneer sheets. Such specially selected wood may be expensive. Therefore, the present disclosure allows for a relatively inexpensive production of a board product with veneer.

Additionally, this allows the production of a veneer 3 surface with much more interesting features such as knots 9, etc. which gives a vivid and appealing esthetic feature.

From a single flitch 1 , a large number of veneer sheets 3 may be produced as shown in fig 3. Thanks to the ability of the bandsaw to cut almost any cross-section into useable veneer sheets, very little material is wasted.

Figs 4-6 illustrates further preparation of veneer sheets and attaching of veneer sheets to a base board. If desired, a number of veneer sheets 3 may be assembled into a compound veneer sheet 11 by applying glue, such as melamine urea formaldehyde (MUF), polyvinyl acetate (PVAc), ethylene-vinyl acetate (EVA), on the longitudinal side edges of the veneer. This is facilitated by the veneer being relatively thick in comparison to traditional veneer. An additional veneer sheet 3 is then applied with a side edge facing the aforementioned glued side edge, thereby increasing the compound veneer sheet 11 area, as illustrated in figs 4 and 5.

Fig 6 illustrates attaching of a compound veneer sheet 11 onto a base board 13. As mentioned, the base board may consist of different material, such as Particle boards, FIDF boards, MDF boards, OSB boards, and hollow boards, depending on the intended purpose of the finished board product. A hollow board, such as the types of hollow boards described in WO 2010/069994, WO 2012/048738 and WO

2018/004430 for instance, comprising a framework and outer surfaces enclosing an air- or foam or honeycomb -filled inner space is very light, and may be used for example as a door of a cabinet or a closet. An FIDF board on the other hand, is heavier but gives a more solid appearance and may be used as a shelf, for example. Generally, a base board for a veneer can be chosen that provides low cost and desired technical advantages in the intended application. For instance, MDF or FIDF boards can be produced at low cost with arbitrary surface areas and may behave in a stable manner under varying temperature and humidity conditions. As a comparison, solid wood, on the other hand, may split and wrap under such conditions, and may be substantially heavier.

As shown in fig 6, a compound veneer sheet 11 may be attached to a main surface of the base board 13 by gluing, although it is also possible to attach single veneer sheets 3 (cf. fig 3) one by one. If desired, veneer may be attached to both main surfaces, and also to edge surfaces.

The glue 15 may for instance comprise melamine urea formaldehyde (MUF), polyvinyl acetate (PVAc), ethylene-vinyl acetate (EVA), and the compound veneer sheet 11 may be pressed against the main surface of the base board with a press applying, for example, a temperature of 80-120°C and a pressure of 100 to 500 kPa

Veneer may be applied to one or both main surfaces of the base board 13, and also to the edge surfaces, if desired.

Optionally, the interface 17 at two adjacent longitudinal veneer sheet 3 edges may subsequently be depressed towards the base board 13 using rolling tools 19, such as pressing wheels, as schematically illustrated in fig 7. This provides, if desired, a valley 25 extending between the two adjacent veneer sheets to create a depth effect, making the board product resemble solid wood to a greater extent. The valley 25 is indicated on the bottom side of the board in the cross section of fig 7. The thickness tb of the board 13 and the thickness tv of the veneer 3 on both flat sides of the board 13 are also illustrated in fig 7.

Fig 8 illustrates one possible application of a furniture board product 21 produced as described herein, where the board product 21 forms a door in a cabinet 23.

Numerous possible other applications exist, including tables, chests of drawers, book shelves, drawer front pieces, kitchen work benches, etc.

The present disclosure is not limited to the above-described examples and may be varied and altered in different ways within the scope of the appended claims.