Radial sawing of wood. Sawing and Sawing Wood

Interested in the rules for industrial cutting of wood, as well as the differences and characteristics of wood in different ways sawing. So, if anyone is interested, read on. The knowledge will be useful when purchasing building materials and building a country house.

There is a radial cut, in which the cutting plane passes through the core of the trunk. The wood of such boards is quite uniform in color and texture, the inter-ring dimensions are minimal. Boards radial cut-2 resistant to external influences, are practically not subject to deformation and have high wear resistance. The radial cut board has a shrinkage coefficient = 0.19% and a swelling coefficient = 0.2%. These indicators for radially cut lumber are twice as good as for tangentially cut boards. For a radial cut board, the process of shrinkage and swelling occurs along the width of the fibers - the thickness of the board, and for a tangential cut along the width of the board, because the fibers at the "tangent" are located along the width. Accordingly, floor boards, parquet boards, imitation timber, block houses, linings - radial cuts - have practically no cracks compared to similar tangentially cut products. design features:

Since the yield of radial cut boards is 10–15% of the total volume, their cost is quite high. Sawing scheme for maximum production of boards with radial-2 and semi-radial cutting-3.

Tangential-1 is a cut in which the cutting plane passes at a distance from the core, tangentially to the annual layer of the trunk. Such boards have a pronounced texture and a rich wave-like pattern of annual rings. Tangential cut boards - 1 have higher shrinkage and swelling coefficients, but are more affordable.

Radial sawing-2 wood is a method of cutting a log in which all the fibers in the board run along the direction of the annual rings. When radially cut, lumber has the best physical and mechanical properties. The strength and hardness of wood with radial cutting is higher than with tangential cutting.

The yield of radial saw-2 boards is usually small (does not exceed 30%). On the UP-700 longitudinal sawing machines, the yield of radial cut boards reaches 60%. This high rate is achieved thanks to the cutting optimization system. By choosing among the optimization criteria the maximum yield of a radial cut board, the conditions of radial and semi-radial-3 cuts, the technologist determines the percentage of yield of the radial board.

The range of lumber offered is quite wide; woodworking products vary in quality, cost, as well as types of wood cutting. Let's take a closer look at what types of wood cutting exist, and to do this, first let's look in general terms at what the technology of wood cutting actually is.

Forest cutting

First of all, the log is unraveled on a belt or disk sawmill, turning into a gun carriage. If all sides are sawn, then the output will be edged material, which is divided into timber, small timber and edged boards. Planed boards are called lining, floorboards, platbands and baseboards. Glued products include, for example, furniture panels.

There are two main types of cutting wood (logs) into boards (lumber):

radial;
tangential,

as well as three additional types:

mixed;
semi-radial (rustic);
central.

Types of board cuts

Radial cut- this is a cut in which the axis of the cut passes through the core of the log and, as a result, the lines of annual rings in the section of the board form an angle of 76 - 90 degrees. with its faces (two main planes of the board). The wood of radial cut boards is quite uniform in color and texture. Such boards practically do not deform when dried and do not swell when moistened, because the change in wood dimensions occurs mainly along the line of the rings (across the grain), and for radial cut boards they are located along the thickness. Radial cut lumber has the highest performance indicators compared to lumber of other types of cut.

Tangential cut- This is a cut that is made along tangents to the lines of the annual rings of the trunk at some distance from its core. The surfaces of such boards have a pronounced texture and a bright wave-like pattern of annual rings. For tangentially cut boards, the coefficients of shrinkage and swelling from moisture are twice as high as for radially cut boards, which causes their significant deformation when the humidity state changes. For this reason, tangential cut boards are less preferable for use in wet conditions than radial cut boards.

Rustic (semi-radial) and mixed cuts- these are cuts with signs of two main types of cuts at the same time: radial and tangential and, as a result, have indicators averaged between them. In a rustic cut, the lines of annual rings have the form of straight lines located at angles of 46 - 75 degrees. to the layers, and mixed cutting these lines change from straight at the edges (width) of the board to arched in the middle.

Central cut- This is a cut made directly in the center of the trunk and including its core. Considering that the core of the trunk consists of the least durable wood, center-cut lumber has the most heterogeneous structure in terms of strength of all the types considered.

Features of the main types of cutting

At tangential cutting the cut plane runs tangentially to the annual layers of the tree at some distance from the core. Since wood fibers, as a rule, do not have a single direction, they create natural patterns on the surface of the board in the form of fancy “arches”, “curls”, “rings”. The texture of the resulting tangential cut board is uneven and may contain wood pores. Some of the dry boards may develop delaminations on the surface after finishing planing. After tangential cutting, the boards are characterized by more high odds shrinkage and swelling; moreover, such a log sawing scheme allows you to increase the useful yield coefficient, which in turn leads to a reduction in the cost of the board.
For radial cutting of wood, the cutting plane is located perpendicular to the annual rings. With this method, the texture of the board is quite uniform with minimum distance between annual layers. This not only creates a beautiful pattern, but also increases the strength of the lumber.

Boards radial cut They are distinguished by good resistance to external influences, have greater resistance to deformation and wear resistance than tangentially cut boards.

The shrinkage and swelling coefficients of radially cut lumber are 0.18% and 0.2%, respectively, which is almost two times better than that of tangentially cut lumber. The reason for this phenomenon is that for radial cut boards, shrinkage and swelling occur along the thickness of the material, in contrast to tangential cut boards, in which dimensional changes occur along the width of the board. This explains the fact that finished products ( parquet board, floor board, block house, imitation timber, lining) from radially cut lumber there are almost no gaps on the front surface, which is not excluded in products made from tangentially cut lumber. To obtain laminated veneer lumber by splicing wood without knots, blanks and boards of radial and semi-radial cuts are used, since the mechanical and geometric characteristics of the timber depend on the resistance of the fibers, which increases when gluing layers with multidirectional annual rings with an inclination angle of up to 45°.

The average useful yield of radial cut boards is only 10-15%. This explains their high cost. Radial cutting includes lamellas in which the angle between the annual rings and the blade is 60-90°. If the specified angle is in the range of 45-60°, such boards are classified as semi-radial cut. The best performance properties are found in lumber in which the angle between the annual layers and the cutting plane is 80-90 degrees. Taking into account semi-radial cut boards, the useful yield coefficient can reach 30%.

Typically, when radial sawing, the log is initially sawn into quarters, and then from each quarter, boards are sawn off alternately from two layers. For sawing logs in a radial way, for example, UP-700 longitudinal sawing machines can be used. Important has a microprocessor control and optimization system UP-700, which is used by technologists to determine the percentage of yield of radial cut boards based on the criteria for optimizing the maximum yield finished products, as well as the conditions of radial and semi-radial cutting.

Comparing radial and tangential types of cuts, several conclusions can be drawn:

Radial lumber has best properties shrinkage and swelling.
Radial cut boards have the best mechanical characteristics and stability of geometric dimensions.
The wood of radial cut boards has a uniform shade and uniform texture, which gives a special decorative value to finished wood products.
Due to their characteristics, radial boards are more widely used, although they have a higher price.

Main dimensions of lumber

Exist standard dimensions lumber. For example, the cross-section of a beam can be 10x10, 10x15 or 15x15 cm, and the length is 6 m. Deviation from these standards will require a special order and will also be associated with additional financial costs. The most expensive is profiled timber, manufactured in-house high class cleanliness.

The edged board can be 2.5 cm, 4 cm or 5 cm thick, 10 cm, 15 cm wide, and a standard length of 6 m. The length of small timber, in addition to the standard value of 6 m, can also be equal to 3 m Its cross-section will be 4x4 cm or 5x5 cm. By-product The production of these lumber is slab, on one side of which there is a face, and on the opposite side there is untreated wood.

Criteria for choosing lumber

Before choosing good lumber, the first step is to find out the type of wood being offered. It can vary from 4 to 0 depending on the number of knots and their quality. It is imperative to check the length of the lumber and the cross-sectional dimensions. If bends or rotational deformations are visible, then it is better to refrain from purchasing such products. You can check the evenness of the lumber by applying a stretched cord.

For many centuries, humanity has been using wood as a building material and, despite the constant emergence of new ones, modern materials, popularity natural wood does not decrease at all.

How to choose the right lumber from a huge assortment? What causes the differences in price and quality?

Quality finished materials made from wood depends on many parameters - the type of wood and the quality of the original timber, the professionalism of the machine operators, compliance with the technology of drying lumber and the production of finished products. Another factor that has a significant impact on the quality and appearance lumber, as well as their mechanical properties, is the method of cutting wood that determines the texture of the board.

There are several types of wood cutting - tangential, radial, rustic and transverse, of which the first two are most widespread. To understand the difference between types of cuts, you need to have a good knowledge of the structure of wood and understand the technology of sawing wood.

In cross-cutting, wood is cut across the grain. The method is used in the production of artistic parquet. A rustic cut is any cut made at an acute angle to the direction of the grain. The method is used in the production of lumber for rustic flooring - the most heterogeneous and original in pattern and shade.

With a tangential cut, the cut plane runs tangentially to the annual layers of the tree at some distance from the core. Since wood fibers, as a rule, do not have a single direction, they create natural patterns on the surface of the board in the form of fancy “arches”, “curls”, “rings”. The texture of the resulting tangential cut board is uneven and may contain wood pores. Some of the dry boards may develop delaminations on the surface after finishing planing. After tangential cutting, boards are characterized by higher coefficients of shrinkage and swelling; moreover, such a scheme for sawing logs allows an increase in the useful yield, which in turn leads to a reduction in the cost of the board.

For radial cutting of wood, the cutting plane is located perpendicular to the annual rings. With this method, the texture of the board is quite uniform with a minimum distance between the annual layers. This not only creates a beautiful pattern, but also increases the strength of the lumber.

Radial cut boards are distinguished by good resistance to external influences, have greater resistance to deformation and wear resistance than tangential cut boards.

The shrinkage and swelling coefficients of radially cut lumber are 0.18% and 0.2%, respectively, which is almost two times better than that of tangentially cut lumber. The reason for this phenomenon is that for radial cut boards, shrinkage and swelling occur along the thickness of the material, in contrast to tangential cut boards, in which dimensional changes occur along the width of the board. This explains the fact that in finished products (parquet boards, floor boards, block houses, imitation timber, lining) made from radially cut lumber, there are almost no gaps on the front surface, which is not excluded in products made from tangentially cut lumber. To obtain laminated veneer lumber by splicing wood without knots, blanks and boards of radial and semi-radial cuts are used, since the mechanical and geometric characteristics of the timber depend on the resistance of the fibers, which increases when gluing layers with multidirectional annual rings with an inclination angle of up to 45°.

Typically, when radial sawing, the log is initially sawn into quarters, and then from each quarter, boards are sawn off alternately from two layers. For sawing logs in a radial way, for example, UP-700 longitudinal sawing machines can be used. Of great importance is the UP-700 microprocessor control and optimization system, which is used by technologists to determine the percentage of yield of radial cut boards based on the criteria for optimizing the maximum yield of the finished product, as well as the conditions of radial and semi-radial cutting.

Comparing radial and tangential types of cuts, several conclusions can be drawn:

Radial lumber has better shrinkage and swelling properties.
Radial cut boards have better mechanical characteristics and dimensional stability.
The wood of radial cut boards has a uniform shade and uniform texture, which gives a special decorative value to finished wood products.
Due to their characteristics, radial boards are more widely used, although they have a higher price.

The main products of sawmill production are sawn materials. Minor – sawdust and wood chips, which are used for the manufacture of particle boards, fuel pallets, etc.

Types of materials produced on a sawmill

If you follow the “letter” of GOST 18288-77, the materials that are produced at the sawmill include:

1) Lumber

Lumber– wood blanks with two plane-parallel layers and certain dimensions specified in the standards.

Bars– lumber, the width and thickness of which is more than 10 cm, is widely used in the construction of houses, as load-bearing structures, for internal and exterior finishing, manufacturing stairs, windows, etc.
Bruschi– lumber in which the width does not exceed double the thickness. According to geometric parameters, square and rectangular bars are distinguished. Depending on the length, these lumber are used as floor joists, bases for wall cladding, in the construction of gazebos, bathhouses and other small architectural forms, and in furniture production.
Boards- lumber in which the width exceeds the size of double the thickness. Depending on the presence of bark on the side edges, they are divided into trimmed and unedged. Edged boards are more in demand for the manufacture of furniture, windows, doors, for various finishing works- in a word, where not only the strength qualities of wood are important, but also aesthetic parameters. Unedged material costs an order of magnitude cheaper, so you can buy it either for self-processing into edged board to reduce the cost of production, or is used in construction as an auxiliary material (for lathing roofs, for making decking, etc.).
Sleepers– bars established size and molds that are made as supports for railway rails;

2) Blanks

Blanks – edged lumber with wane and edges that are sawn perpendicular to the faces completely or partially. These include plates (half sections of logs) and quarters;

3) Obasexual

Lagging– material with an internal sawn and an external unsawed (or only partially sawn) face. Plank obapol - with a convex part sawn half or more, used for the production of fence pickets and in the construction of formwork, scaffolding, strengthening mine workings;

4) Croaker

Gorbyl– the outermost parts of the log that remain during sawing. The croaker differs from the obapole in that certain ratios of thickness, width and minimum length requirements are not established for it. Most often used as an environmentally friendly fuel or for the production of wood chips.

Lumber elements

Plast– wide longitudinal surfaces of the sawn log and any side of the lumber square section. The inner surfaces are those closest to the core of the log, and the outer surfaces are the surfaces that are farthest from the core.

Edges– narrow surfaces, the processing method of which determines the division of lumber into edged, partially edged and unedged;

Edge– the intersection of adjacent two sides of lumber;

Ends– surfaces perpendicular to the edges.

Classification of lumber according to sawing method

Depending on the location of the layers to the annual layers, lumber is divided into:

1) Made by radial sawing

A radial cut is a cut in which the cut passes through the core of the log, at right angles to the rings. In this case, the surface of the layers is uniform in texture and color, and the distances between the annual rings are minimal.

Boards made by radial sawing have excellent quality indicators (swelling coefficient 0.2%, shrinkage coefficient 0.19%). Therefore, radial lumber is in demand for the manufacture of parquet, timber, lining, block house - the finished products have practically no gaps, in comparison with similar tangentially cut products.

Lumber made by radial sawing is the most durable and expensive. They are used in construction, in the production of massive panels and window beam The yield of a radial board is usually small (30% is already a good indicator), and depends on the method chosen for cutting the log. Optimal scheme cutting to obtain radial and semi-radial boards is considered as follows.

2) Made by tangential sawing

When cutting a log tangentially, the saw passes tangentially to the annual layers of the trunk without touching the core of the tree. Such lumber has a wavy pattern, which clearly shows the patterns of annual rings and beautiful wood structure.

For tangential boards, the coefficient of shrinkage and swelling is at least twice as high as that of radial material, so their cost is more affordable and the quality of the products is lower. Such boards are not used for the main building elements - the wood can be deformed and the product will “lead”. But, nevertheless, due to its high aesthetic qualities and low price, the demand for tangential wood is high - it is used for decorative finishing furniture, doors, building elements.

Wood is valuable natural material which was created by nature itself. People have been using this wonderful raw material for many centuries to build houses, create furniture, decorative interior items, and also use it for industrial purposes. For these reasons, proper processing of a felled trunk is an extremely important task. Sawing and planing wood are the most important operations with wood. In this article we will talk about what wood sawing is and what types of sawing exist.

Log sawing is the process of converting valuable natural raw materials into lumber. When sawing wood various methods available various sizes lumber To obtain high-quality products, you need to choose high-quality, even logs that are not damaged by pests.

Types of wood cutting

The quality of the final product depends on large number factors - type of wood and quality of raw materials, professionalism of workers, proper drying. However, there is another important aspect - this is the method of cutting timber.

There are the following cutting methods:

tangential
radial
rustic
longitudinal
transverse.

Rustic is a cut that is made at an acute angle to the direction of the grain. This method is used in the production of lumber for rustic flooring, which can be called the most heterogeneous and original in pattern and shade.

During tangential cutting, the cutting plane lies tangentially to the annual layers of the material at a certain distance from the core. Since wood fibers are most often located in different directions, a natural pattern in the form of fancy “arches”, “curls”, “rings” is obtained on the surface. The structure of the board with this cutting option is heterogeneous; wood pores may be present. At the end of the tangential cut, the boards are characterized by an increased coefficient of shrinkage and swelling. Also, this log sawing scheme makes it possible to increase the useful yield coefficient, which causes a reduction in the cost of the final product.

Sawing wood blanks using the radial method is carried out perpendicular to the annual rings. Thus, a homogeneous board is obtained with the smallest gaps between annual layers. This creates an attractive pattern and also increases the strength of the lumber. Radial materials are characterized by high resistance to deformation and wear resistance. Also, such boards have lower rates of shrinkage and swelling compared to tangentially cut lumber. Therefore, finished products, for example, parquet boards, batten, block house, lining, practically do not crack on the front part, but tangential sawing materials are susceptible to such phenomena. Glued laminated timber is created only from radial and semi-radial cut boards, because the mechanical and geometric parameters are directly dependent on the resistance of the fibers. This resistance increases during gluing of layers with multidirectional annual rings at an inclination angle of no more than 45°.

From solid log only 10-15% of radial boards can be obtained. Therefore they have a high cost. The best performance is demonstrated by material having an angle between the annual layers and the cutting plane from 80 to 90 degrees.

Sawing wood across the grain

The technology of sawing wood across the grain is the most common method of processing timber in carpentry. At the same time, such sawing can be called the simplest. Longitudinal sawing wood requires much more effort and certain skills.

Tools for cross-cutting timber are selected depending on the required accuracy, the amount of work and the conditions available in each individual workshop. You can use:

electric circular saw. She makes neat and fast cuts. For household use Great suitable model with a 1000 W motor and a disk cross-section of 180 mm. Most of circular saws have a combined blade included, which can be used to implement the most various works. The teeth of this blade are something between the teeth of a transverse and longitudinal saw. For long work It is better to take a blade that is coated with carbide. Its cost is higher, but it takes 10 times longer to dull
miter box and tenon saw. They are used for finishing. These tools can be used to make the most precise cuts.
circular saw
cross saw. When purchasing, please note that the teeth of such a tool should be alternately positioned to the left and to the right of the blade itself. They must be well sharpened and beveled. The most popular is a saw with 10 teeth per 25 mm blade. With 8 teeth, the saw will cut faster, but will create rough cuts.