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.
If you follow the “letter” of GOST 18288-77, the materials that are produced at the sawmill include:
Lumber– wood blanks with two plane-parallel layers and certain dimensions specified in the standards.
Blanks– edged lumber with wane and edges that are sawn perpendicular to the facets in whole or in part. These include plates (half sections of logs) and quarters;
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;
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.
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.
Depending on the location of the layers to the annual layers, lumber is divided into:
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 beams. 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.
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.
Building materials made from hardwood and softwood have a wide range of applications; they are used for the construction and cladding of houses, paving paths, interior design building. The lumber on the market is divided according to the cutting method; it can be tangential, radial, longitudinal, disk or mixed. Depending on the presence of edges, boards are classified into edged, semi-edged and unedged.
Mechanical processing of logs can be carried out using special machines or electrical appliances by cutting or splitting. There are the following methods of cutting wood: planing, turning, drilling, grinding, all of which involve removing chips. There are three types of cutting - longitudinal, transverse and straight. The first involves cutting along the fibers, the second and third – perpendicularly. Sawing is the main stage in the manufacture of all lumber; the operational and aesthetic characteristics of the finished product depend on the quality of the procedure.
This method of processing logs is considered one of the most popular. With a tangential cut, the plane of the cutter passes at a certain distance from the core of the trunk, tangentially to the growth rings. The result is practical and durable boards that are resistant to shrinkage and swelling. Such lumber has an attractive texture - the graceful wave-like pattern of annual rings is clearly visible on them. Boards obtained by tangential cutting can be used for exterior decoration of buildings and creating a cozy interior.
High-quality parquet is also produced in this way. When cut perpendicularly, a natural pattern is visible on the boards - rings, arches, waves, curls. If the parquet is made from Siberian larch, it can be used for laying flooring in rooms with high humidity, since products made from this rock, when in contact with water and steam, not only do not collapse, but also become stronger. Wooden flooring, created as a result of tangential sawing, will last for many years without needing repairs or renovations.
It is customary to call a radial cut of a log, carried out perpendicular to the annual layers. Lumber produced by this method has a uniform texture, they are characterized by increased strength and wear resistance, and are practically not subject to deformation. Radial cut boards have minimal shrinkage and swelling coefficients, so they do not collapse due to negative influences environment and are great for external cladding buildings. With this processing method, lumber has virtually no flaws. Defects may be caused by a violation of sawing technology (displaced core, incorrect size).
Radial sawing is used for the production of edged boards, a popular lumber used for finishing houses, dachas and cottages. If the cladding is made of Siberian larch, it is perfectly would be better suited for decoration of baths, saunas and bathrooms. Products from this coniferous do not require additional processing, have an attractive texture and have a long service life. Edged board Widely used by interior designers, it can be used to create a cozy atmosphere in a room. Lumber from Siberian larch contains resin, when released, it spreads a pleasant aroma.
Semi-radial sawing is a common method of producing lumber. It involves cutting logs at an angle of 45°. This technology allows you to save raw material and reduce the cost of the finished product. The only drawback this method cutting is that the resulting board may be subject to deformation due to improper drying. Therefore, special attention must be paid to preparing wood for processing.
Semi-radial sawn timber can be made from both hardwood and softwood. Products made from Siberian larch are especially popular today; their demand is due to their strength, resistance to mechanical damage and aesthetics. Coniferous cladding reliably protects the building from the effects of atmospheric phenomena, helps retain heat and create a comfortable microclimate indoors.
For the production of lumber, modern high-tech equipment should be used, only in this case the finished product will have a minimum of defects. The amount of waste generated when cutting wood also depends on the characteristics of the special equipment. Today, angle sawing machines are used for the production of boards, beams, and parquet; due to their special design, they make it possible to produce high-quality products and reduce the amount of waste. Using equipment for radial sawing, you can produce not only radial, but also edged lumber. The basis for creating molded products is a log - a tree trunk freed from branches. Wood cutting can be done in various ways:
To use existing logs rationally, the craftsman needs to carefully study the sawing pattern (tangential, radial, longitudinal, mixed). Knowing how to distribute raw materials can reduce waste and significantly increase profits. Suitable for the production of wooden building materials at home manual method, which involves the use of chainsaws and hacksaws. However homemade boards and beams, as a rule, have defects and look unaesthetic. It is advisable to buy attractive lumber from specialized companies. Large enterprises carefully control the quality of their products.
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 actual technology of wood cutting is.
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 patronage is called lining, floorboard, platbands and baseboards. Glued products include, for example, furniture panels.
There are two main types of cutting wood (logs) into boards (lumber):
as well as three additional types:
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 due to 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 in a mixed cut these lines change from straight at the edges (along the 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.
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, 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 minimum distance between annual layers. This not only creates beautiful drawing, but also helps to increase the strength of lumber.
Boards radial cut have 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 finished products ( parquet board, floor board, block house, imitation timber, lining) from radial cut lumber on front surface almost no gaps are observed, 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%.
Usually, when radial sawing The log is initially sawn into quarters, and then boards are sawn off from each quarter, alternately from two layers. For sawing logs in a radial way, for example, UP-700 longitudinal sawing machines can be used. The microprocessor control and optimization system UP-700 is important, 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 cuts, several conclusions can be drawn:
There are standard dimensions of 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 to the highest cleanliness class.
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 3 m Its cross-section will be 4x4 cm or 5x5 cm. A by-product of the production of these lumber is a slab, on one side of which there is a face, and on the opposite side there is untreated wood.
Before you choose 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.
Sawing lumber- a fundamental process in wood processing. First, we need to recall a few terms that are used in the woodworking industry and which are defined by GOST 18288-87 sawmill terms and definitions:
Lumber. Materials that have one or more straight sides. Depending on the ratio of length to width and the number of parallel sides, timber, beams, boards, obapol and sleepers are distinguished.
This is very important factor, the overall yield of lumber and its quality largely depend on the chosen method. Depending on the direction of cutting to the annual rings, there are two methods:
The choice of a specific cutting method depends on the end use of the lumber and the condition of the log. On the Internet you can find “strange articles” about circular sawing and so on. In fact, the vast majority of the logs are in one position during sawing; as a result, some of the lumber has a tangential cut (about 2/3 of the total), and the rest of the lumber has a radial cut. The top and bottom of the log are sawn tangentially, only its middle is sawn radially.
At the request of the customer or taking into account our own production, the pole can be sawed from the sides, then turned 90°, and sawing is done again. As a result, some of the boards are unedged, tangentially cut, and the rest of the boards will be edged with a radial cut. Let us repeat once again that cutting methods are selected in each specific case separately, taking into account the above factors. Currently, there are three types of sawmills, each of them has its own advantages and disadvantages. Let's talk about them in more detail.
These were the first mechanisms that began to be used for mechanical sawing of wood. Today, in our opinion, they have undeservedly gone out of fashion. Let's take an objective look at their advantages and disadvantages.
To make it clearer, you need to learn about the principles of operation. On a frame sawmill, several saws are fixed in a vertical position (from ten or more, it all depends on the size of the frame), the distance between the saws is set once, sawing is carried out by the vertical movement of all saws with the simultaneous feeding of the blade.
pros.
Minuses
They are considered the most advanced equipment, the most productive, the amount of sawdust is minimal. We will discuss this later, but first we will briefly describe their structure and principle of operation. The cutting is done with closed high-speed saws, the thickness of the saws is small, the width of the cut is reduced. The cutting occurs due to the forward/reverse movement of one saw along the blade. To be honest, we don’t notice any particular advantages (for the buyer), but there are disadvantages. In order not to be unfounded, we will talk about the intricacies of the cutting process.
Sawmills require a very careful attitude. Incorrect sharpening of the teeth, incorrect tension or selection of cutting speed (all of these parameters are selected taking into account the type of wood) lead to the fact that the lumber gets a wavy surface. The height of the waves can reach several centimeters. And such waviness of even one board negates all the “advantages of thin cutting.” A wave on lumber is a visible processing defect and reduces the grade of lumber. The classification of wood defects is described in detail in the article of the same name.
These sawmills have rather low productivity and require a lot of physical labor. For example, if your log has a diameter of 100 cm, then calculate how many passes back and forth you need to make to cut it into boards 2 cm thick, and the frame sawmill will cut it in one pass. In addition, each sawn board must be manually removed from the sawmill and stored in a separate place. In this case, after each cut you have to set the saw level again. Very high degree of danger during operation. The risk of injury while working at such a sawmill increases exponentially - this includes the breakage of the saw at high speeds, and the presence of metal objects in the body of the tree (and this happens not so rarely). Problems with sawdust removal. They scatter along the entire length of the sawmill, removing them is long and difficult.
Of course, manufacturers of band sawmills are “bashfully” silent about such “subtleties”. We advise you to take into account the maximum number of factors when choosing a sawmill: the required volume of lumber, the availability of qualified personnel, the characteristics of lumber and requirements for their quality. After all, professional workers band sawmill produce 1st grade lumber in accordance with GOST.
pros.
Minuses
Circular saws differ from band and frame (multi-saw) sawmills in the quality of edges and parallelism of the face. Lumber produced on a circular sawmill is rightfully considered the best, but only from the consumer’s point of view. The main fact that makes lumber produced on a circular sawmill unavailable for consumption is its high price. High price does not allow you to compete in the market building materials, despite the excellent quality of boards and timber produced by this method. This circumstance is connected with three facts that influence the increase in the cost of lumber from a circular sawmill:
Summarize: when choosing edged lumber, you need to take into account not only the method of sawing the lumber, but also the qualifications of the personnel servicing this equipment. Buy lumber good quality You can contact a trusted supplier by looking at the products using the photos offered on the manufacturer’s website or by visiting the finished product warehouse. The Elka-Palka company is ready to offer its services in accordance with the price lists listed on our website. We sell only high-quality products of our own production or purchased from trusted suppliers. Mandatory quality control.
as well as three additional types:
Scheme of types of log cutting
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 due to 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 in a mixed cut these lines change from straight at the edges (along the 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.
