Technology for making wood bending with steaming. Tips for the master: how to bend wood Bend wood-like material into a tube

Wood is recognized as one of the safest materials for human health used in construction and in the manufacture of various furniture. Its environmental friendliness can be rated five points, which significantly expands the scope of use wooden products. Wood can be used to produce workpieces of various shapes and sizes. Special ones help with this. These technologies also include wood bending and gluing, which is widely used in the modern production cycle.

The entire woodworking process takes a significant amount of time. First the wood - all this happens in woodworking enterprises. Subsequently, boards and other materials are prepared from wood.

These blanks are sent to factories, where they are specially made from them. building materials or various furniture. During the production process, wooden blanks of different shapes and sizes may be required, and therefore woodworking techniques such as bending and gluing are widely used.

Bonding is used to produce parts of the desired size and shape. Wood splicing can be done by width, length or thickness. Pre-prepared ends of the workpieces can have special grooves or tenons, which increases the strength of the parts being connected. Different types of wood glue are used in the gluing process.

Wood bending is necessary to produce curved parts. You can bend wood manually, subject to certain features of this work, or on special machines.

The strength and practicality of wooden products, for the manufacture of which special machines for gluing or bending are used, can be rated at five points. Woodworking factories always try to follow all the technology of working with wood, and therefore the goods produced are of high quality.

Photos of the wood processing methods described above

Splicing Gluing Bending

Main stages of gluing technology

Gluing is the main process of working with wood on any furniture production. In order to obtain a durable and high-quality workpiece, it is necessary to strictly adhere to the entire technology of the process of connecting individual parts. The accuracy of all work is also necessary to prevent possible subsequent deformation.

The process of joining wood and products made from it consists of several stages:

Preparation of the blanks themselves.
Selection and application of adhesive composition.
Actually the gluing itself.

Preliminary preparation of wooden blocks and other workpieces consists of creating special tenons or grooves in them, which can be done using a special tool - a milling cutter.

Using a cutter to join wood

Milling is a fairly old branch of wood processing. The first milling machines appeared more than three centuries ago. Today, milling is an indispensable and universal method wood processing.

For this woodworking machine, you can choose cutters of different shapes - sharpened elements with different types of blades. Using these cutters, various parts are made.

In the gluing process, milling machines are necessary for:

Cutting tenons of different shapes, with the help of which individual workpieces will be glued together in the future.
Creating holes in the material. Creating folds and grooves, which are also necessary in the process of manufacturing parts of different shapes.

Milling machines are used everywhere, they can be either manual or electric. The ease of making wooden blanks for gluing using a machine can be rated four points. In order to obtain an accurate workpiece, you first need to gain some experience.

This video provides an overview of cutters for splicing wood and making technological connections. Shown are cutters for straight and angular splicing, as well as a microtenon, zigzag and wave cutter:

Automatic line for wooden blanks

Splicing lumber in any production allows you to create high-strength materials with new, sought-after qualities and also allows you to rationally manage production waste.

Automatic splicing lines include several sequentially operating machines, which ultimately allow you to obtain the required length and width of the material from short workpieces. With the help of a splicing line, glued laminated timber, which is popular today, is produced.

The entire technological process when using a production line for splicing wooden blanks consists of several stages, which are provided by a complex of machines included in the installation:

The cutting press machine provides the required dimensions of the material.
A router prepares tenons and grooves in wood pieces.
The gluing installation distributes the glue in accordance with the set parameters.
The cross-cutting machine completes the gluing process.

Using a splicing line in furniture factories ensures high productivity and reduces the number of jobs. , obtained using automatic machines, can be rated five points, since the entire process is strictly controlled.

This is how an automatic length splicing line works:

Types of glue

The correct selection of the type of glue determines the quality of joining wooden workpieces. The choice of glue also depends on the type of wood being glued and the shape of the workpieces. Waterproof adhesive compositions are most often used.

The furniture industry uses several types of synthetic adhesives:

Thermosetting adhesives are used for gluing tenon parts without heating. The basis of these types of glue are liquid resins.
Phenol-formaldehyde adhesives are used for gluing wood boards, wooden blanks and plywood.
Epoxy adhesives are mainly used for joining wood with other materials - metal, plastic.
At woodworking enterprises, glue based on urea resins is most often used. Also often used adhesive compositions in powder form, which require preliminary preparation.

Bonding of parts is carried out coldly and by heating them. To glue workpieces along the edges, adhesive film is often used; it comes in sheets of various sizes.

Before gluing, the parts must first be prepared, that is, degreased, removed dirt and various types of stains. After applying glue over the entire surface and connecting the required workpieces, the parts are clamped using special devices, which are removed only when completely dry.

Machine tools

To splice glued wood, special machines in the form of presses can be used. They clamp the parts for the required time. This ensures a strong connection between the adhesive surfaces and prevents movement of parts. The press can be selected according to the length of the beam, power, and the presence of additional functions.

Gluing wood at home

Wood gluing may sometimes be required at home. This often happens when wooden furniture sets are glued together or due to various breakdowns. Before gluing, the surfaces of wooden products must be properly prepared.

To do this, their pores are cleaned of old glue and paint layers, degreased with a solvent, and dried. After applying glue to both parts, they are carefully connected and clamped in a clamp for at least 30 minutes.

Commonly used adhesives include:

Casein glue.
Waterproof seams are provided by synthetic wood glue.
Strong bonding is obtained by using glue “Dubok”, “Ago”, “Mekol”, “Mars”.

In order to achieve high strength of the parts to be glued, it is necessary to strictly follow the instructions included with each type of glue.

You can clearly see how wood is glued together in the video:

Bending technology

Wood bending can be defined as the process of bending layered or solid pieces of wood to give them the desired curved shape. Bending technology is based on plastic qualities different types wood. Curvilinear wooden parts can also be obtained by processing on special machines, but this method is rarely used, as it is endowed with a number of negative consequences.

Process Description

Wood has greater ductility hard rocks, such as oak, beech, ash. Therefore, mainly the species of these trees are used for the manufacture of curved parts. There are cold and hot bending of wood.

Hot bending is based on a sharp increase in the plasticity of wooden blanks when they are heated from 80 to 120 degrees. This heating mode is achieved by boiling in water or steaming.

The wooden blanks plasticized in this way are bent according to the prepared template and secured with clamps, after which they are cooled and dried. When bending, the convex side is stretched to the required level, and the concave side is compressed. Thick workpieces are bent using special machines.

Cold bending is used to produce multilayer curved bent parts. To obtain a part of the desired shape, you need to place several blanks coated with glue on top of each other, give them the required shape and, using a press machine, wait the required time. The shape of blanks obtained by cold bending is retained longer.

How they do it curved wood, the video will tell:

Bending wood at home

Wood bending at home begins with the choice of material. The prepared parts must be straight-layered; they must first be dried under natural conditions. You also need to soak parts if they are made of ash, oak, or beech. Before bending, the workpieces must be steamed.

To do this, you can use a steam chamber prepared yourself. To make such a device, a pipe and a boiling kettle are suitable, from which steam will continuously flow into this chamber through hoses.

The holding time of the blanks can only be determined experimentally, but it is believed that in order to achieve the required plasticity, it is necessary that one centimeter of wood in thickness be steamed for 30 to 40 minutes. It is also not worth overexposing the product.

Before you start bending, you need to prepare the mold and clamps. After heating the wood, it can be bent well only for 5-10 minutes, so everything needs to be done extremely quickly. The products are kept in the mold until they are completely dry, usually this takes at least one week. The finished part can then be machined or processed.

They use this wood processing process to make different types of furniture with their own hands. At the same time, the price of the products is significantly reduced and this can be rated five points. But the labor intensity of the entire process takes a lot of time, and therefore only truly passionate people can take up bending wooden blanks and their subsequent use.

Examples of interior elements made from bent wood

Headboard Rocking chair Table Decorative element Chairs

The layers are carefully lubricated with glue, placed in a template and pressed into place. Bent glued units made from veneer, from hardwood and softwood boards, from plywood. In bent-laminated veneer elements, the direction of the fibers in the veneer layers can be either mutually perpendicular or identical.

When manufacturing bent-profile units with longitudinal cuts, it is necessary to take into account the dependence of the thickness of the bent elements on the type of wood and the thickness of the bent part.

As the bending radius of the slab increases, the distance between the cuts decreases, as can be seen in the figure above. That is, the width of the cut directly depends on the bending radius of the slab and the number of cuts.

Now let's consider theoretical aspects bending

Curved solid wood parts can be made in two basic ways:

cutting out curved workpieces and giving a straight bar a curved shape by bending it on a template. Both methods are used in practice and have their advantages and disadvantages.

Sawing curved blanks is characterized by simplicity of technology and does not require special equipment. However, when sawing, the wood fibers are inevitably cut, and this weakens the strength so much that parts with large curvature and a closed contour have to be made up of several elements by gluing. On curved surfaces, half-end and end cut surfaces are obtained and, as a result, processing conditions on milling machines and finishing worsen. In addition, cutting produces a large amount of waste. The production of curved parts by bending requires a more complex technological process and equipment compared to sawing. However, when bending, the strength of the parts is completely preserved and even in some cases increases; end surfaces are not created on their faces, and the modes of subsequent processing of bent parts do not differ from the modes of processing straight parts.

Element bending
A- nature of the workpiece deformation during bending;
6 - bending the workpiece with the tire according to the template:
1 - template; 2 - notches; 3 - pressing roller; 4 - tire

When the workpiece is bent within the limits of elastic deformations, normal to cross section stresses: tensile on the convex side and compressive on the concave side. Between the zones of tension and compression there is a neutral layer, the normal stresses in which are small. Since the magnitude of normal stresses changes along the cross-section, shear stresses arise, tending to move some layers of the part relative to others. Since this shift is impossible, bending is accompanied by stretching of the material on the convex side of the part and compression on the concave side.

The magnitude of the resulting tensile and compressive deformations depends on the thickness of the bar and the bending radius. Let us assume that the block rectangular section bent in a circular arc and that the deformations in the bar are directly proportional to the stresses, and the neutral layer is located in the middle of the bar.

Let us denote the thickness of the bar H, its initial length through Lo, bend radius along the neutral line through R(Fig. 60, a). The length of the block along the neutral line when bending will remain unchanged and is equal to Lo = p R( j /180) , (84) where p is the number pi(3, 14...), j - bend angle in degrees.
The outer stretched layer will receive elongation D L (delta L). The total length of the stretched part of the bar is determined from the expression Lo+ D L= p (R + H/2) j /180 (85)
Subtracting the previous one from this equation, we obtain the absolute elongation
D L= p (H/2)( j /180). (86)
Elongation Er will be equal to D L/Lo = H/2R, i.e. bending elongation D Ll/Lo depends on the ratio of the thickness of the bar to the bending radius; the thicker the block, the larger it is H and the smaller the bend radius R. A similar relationship for the value of relative compression during bending can be obtained in a similar way.
Let's assume that around the pattern R" bent block with initial length Lo and at the same time maximum compressive and tensile deformations are achieved. Designated by E szh the value of permissible compressive deformation of wood along the fibers, and through E grow the value of the permissible tensile strain along the fibers, we can write a relationship for the stretched side
L = Lo(1 + Erast)= p (R" + H) j /180 (87)
From here R" + H = / p ( j /180) .
For the compressed (concave) side there will be L 2 = Lo (1 - Eczh) = p R"(j/180)
or R" = / p ( j /180 ). (88)
Subtracting the second from the first expression, we get
H = )