To obtain a high percentage of lumber from round logs at the output, several different technologies are used, including certain cycles of actions. Sawing by time roundwood and the labor intensity of the process varies, depending on the chosen processing method, the place of work, the season. So, some enterprises build shops for the primary processing of raw materials near the place of logging and save on this.

Not only trunks are processed, but also large branches. Roundwood is sorted by size and bark. Trunks that have not passed sorting are used in the future for rough work (production of scaffolding, etc.). When accepting raw materials from the supplier, not only the cubic capacity is checked, but also the presence of damage, rot, knots - such materials do not comply specifications. Flaws in wood reduce the percentage of finished products at the output, and knots can damage equipment.

Before sawing, trunks are often debarked (removal of bark on a special machine) - this process is optional, but considered economical:

• due to the absence of stuck pebbles and sand in the bark, the saw is preserved from premature wear;
• improves the quality of chip material;
• some enterprises do not accept slabs from unbarked logs for processing;
• the error of the results when sorting the forest with the help of electronics is reduced.

Types of wood cutting

First of all, you need to decide on the type of cut - there are several of them. Tangential - the cut goes tangentially to the growth rings, the surface is obtained with patterns in the form of rings, arches. Boards obtained in this way are cheaper, but have high percentages of shrinkage and swelling.

Radial - a cut along the radius, perpendicular to the annual rings, the pattern is uniform, the output of the board is small, but it is of high quality and greater strength.

Rustic - carried out at any angle, defects, knots, sapwood, etc. are visible.

Cutting methods

For each specific case, a cutting method is selected.

Vrazval - the most economical, almost no waste, a high percentage of finished timber. The output is unedged boards and two slabs.

With a bar - first they get a two-edged bar, unedged boards, two slabs. Then the beam is sawn perpendicular to the saw cut into edged boards, two unedged boards and two slabs are obtained along the edges.

Sector - first, the log is sawn into 4-8 sectors, and then each of them into radial or tangential materials. Sometimes several unedged boards are sawn in the center.

Split-segment - with such a cut, two or more unedged boards are cut in the center of the trunk, and edged one-sided boards are sawn from the segments on the sides.

Beam-segment - similar to break-segment, only in the middle of the log a two-edged beam is cut, which is then sawn into edged boards. The yield of lumber is high.

Circular - after sawing off one or more unedged boards, the log turns 90 0 and the next boards are sawn off. This method is used when a large log is affected by heart rot in the center. With its help, healthy wood is separated from low-quality wood.

Aggregate - with the use of milling tools and circular saws, along with high-quality lumber, technological chips are obtained at the output (instead of slabs and slats). Such complex processing of the forest allows rational use of raw materials and labor costs. It turns out waste-free production of finished lumber.

Required Tool

The choice of tools depends on the quantity of the planned finished product, its quality and the size of the products. Most often, the cut is performed with a circular saw. At certain stages of production, the use of special machines is required.

The circular saw makes precise cuts in any direction, perfectly copes with any size log, suitable for professional and home use.

It is used for home use when it is necessary to prepare a small amount of lumber. It is easier to do more difficult work with a chainsaw than to buy expensive equipment. It will only need a special nozzle, a fixative for the trunk and cutting guides.

Bark removal machines. They are quite expensive, but with regular use in an enterprise where large amounts of work are performed, they quickly pay for themselves. It is not necessary to use them, but it is desirable, because a number of economic advantages and conveniences in the production process can be obtained by doing so.

And you will also need:

• Disc machine - for obtaining unedged materials from the forest at the exit.
• The band sawmill produces high-quality lumber and a low percentage of waste.
• Frame sawmill - does not need a foundation and can be installed directly in logging sites.
• Universal machines are able to produce high-quality material even from low-grade wood.

At enterprises with mass production, entire complexes are installed to obtain ultra-precise and high-quality products. modern equipment, and sawing up the forest is carried out of any complexity.

Technological map of sawing

To calculate the optimal percentage of obtaining finished lumber from a log, a map of sawing the forest is drawn up. These calculations can be done independently or using a special computer program. Such information can still be obtained in the usual directory, which contains information on sawmilling.

The cutting map allows you to determine how many finished products will be at the output, what percentage of waste will be recycled. Based on these data, you can determine the final cost of production. The result can largely depend on the type of forest. There are some measures to increase the yield of lumber.

The percentage of lumber output is ready-to-use, usable wood. Waste - raw materials for the production of MDF, chipboard, fiberboard. These volumes will depend on the diameter of the tree, the types of solid wood products manufactured, and the sawing option.

Percentage of round timber

An accurate count of each cubic meter of wood, an expensive natural raw material, is important at every woodworking enterprise. Cubic meters of roundwood are calculated in several ways.

By volume of transport. For each type of transport, its own cubic capacity of the forest is calculated and established. For example, a wagon holds 70.5 cubic meters of round wood. Then in three wagons it will be 22.5 cubic meters. This method of counting speeds up the acceptance of raw materials, this is especially important with a large amount of incoming cargo. But at the same time, there is a large error in the results of calculations in this way.

Calculation for the volume of one trunk. If the entire logging consists of timber of the same size, then by counting the volume of one, you can count them all and multiply by the cubic capacity of one. This method is more accurate, but it requires a lot of time and attracting more workers to receive the goods.

Automated systems with measuring frames. These measurements give higher percentages of accuracy than those taken by humans. When the logs pass through the measuring frame, all thickening and curvature of the trunk and even knots are taken into account. In this case, you can immediately sort the trunks.

A method of calculation by multiplying the volume by a factor. The height, width, length of the stack is measured and multiplied by a factor. This calculation is fast, but with a low percentage of accuracy. It is used when it is urgent to determine the number of cubic meters.

Dependence of the final yield percentage on sawing technology

To increase the yield of finished lumber, it is necessary to optimize the sawing process itself. This is especially true when working with workpieces that have curvature, damage or other flaws:

• First, you need to select and put into production only high-quality wood.
• Then select trunks with damage at the ends (rot, cracks) and trim these places.
• With a section of the trunk with a rotten core, it is necessary to remove it, and cut the remaining wood into lumber. They will be shorter, but better quality.
• And also for obtaining a high-quality board, the circular cut method is suitable.
• Higher percentage of yield when sawing timber with a large diameter.

The output also depends on the quality of the log, the type of wood, the equipment used. New high-quality, well-tuned equipment allows you to process trunks almost without loss.

The efficiency of cutting the forest can be increased if special measures are taken in advance. To do this, you need to make accurate calculations using digital programs. If this is done manually, then the percentage of marriage in the output will be greater. It should be taken into account in advance that a greater percentage of sawn timber is obtained from coniferous forests. Because their trunks are even, large, less prone to decay and therefore almost without marriage. From hardwood large volume often discarded.

For the rational use of wood, it is better to take short logs. But in domestic production, trunks with a length of 4 m or more are usually taken for sawing. Because of their curvature, the output is a large percentage of marriage.

When sawing wood, it is important to immediately calculate what the consumption will be, as this will affect the cost of lumber. The output of finished products may be different. It all depends on the quality of the wood used, whether measures are taken to optimize cutting. There are special measures to increase the efficiency of work, make the output better, and the quality of sawing is higher. Before cutting, you must first calculate everything. It is not as difficult as it may seem, but the consumption of roundwood will be optimal, beneficial for obtaining an excellent result.

How to increase cutting efficiency

In order for the lumber yield to be significant, it is necessary to use special measures to increase the efficiency of the process:

1. The calculation should be carried out only when using special programs, manually it will have low efficiency, the rejection rate will turn out to be large.
2. The round timber must first be sorted so that the processing is carried out correctly.
3. For cutting, high quality equipment must be used. Otherwise, the amount of waste will be large, and the quality of the resulting lumber will become low.
4. It is best to cut wide lumber first, it takes longer to process narrow lumber.
5. Logs are not recommended to take long.
6. Before work, you must configure the equipment.

The output of finished lumber may be different. It must be remembered that at the first stage boards are obtained, then they are sorted. As a result, the percentage decreases even more, for example, for hardwoods it can be only 10-20%.

How to optimize cutting

In order to increase the output of lumber, the sawing process must be optimized. This applies primarily to those blanks that have a significant curvature. To cut a curved roundwood, you need to perform a series of actions:

1. First, only suitable wood is selected for work. If the remaining logs have rot, sprouts, cracks at the ends, then it is necessary to trim some sections.
2. If a rotten core is found during operation, then you can carefully remove it, and then cut the rest. This will avoid large losses, get boards with a length of 1 m with the required quality.
3. It is recommended to use logs with a larger diameter so that the yield percentage is higher. The coefficient can be 1.48-2.1, but it all depends on the diameter, quality of round timber, sorting, and equipment. For frame workshops, this coefficient will be 1.48-1.6, and for lines with milling equipment - 1.6 for large timber. With a round timber diameter of 12 cm or more, the coefficient may exceed 2.1.

Waste volume after sawing

In order for the finished board to come out with a large percentage, it is necessary to prepare everything correctly, work should be carried out only in accordance with the technology. The round wood of coniferous and deciduous breeds gives various output. In the latter case, the volume is smaller, even if special additional equipment is used. Needles for sawing are considered more convenient, since the trunk is straight, and the log has a larger diameter. Coniferous forest is not so prone to decay, so there is less marriage. For hardwoods, 2 cutting technologies are usually used:

• using a band sawmill at Z75, Z63;
• into collapse, when a half-beam is cut out in the core of the material, passed through a multi-blade machine.

The volume of a band sawmill is 40-50%. When using the technology in the collapse, the yield is different, it can be increased up to 70%, but the costs of such work are higher. If roundwood is sawn, the length of which is 3 m, then you can see that the percentage of rejects is quite large, and the remaining material requires processing. This applies to the bulk with boards 22x105 (110, 115) x3000 mm. There are many options for such a marriage. For example, it may be a wormhole, which is no longer suitable for most jobs.

After sorting, the volume of hardwood material that is grade 0-2 will be only 20-30% of the amount that is obtained after sawing. This means that from the total mass of harvested roundwood, the output of a normal board will be only 10-20%. The rest of the materials are mainly used for firewood. Coniferous round timber will have a different yield, but attention should be paid to what average values ​​of the obtained volume are observed.

lumber output

In order for the lumber yield to be optimal, numerous conditions must be taken into account. For a correct calculation, you can consider the example of the output of roundwood. The data was obtained on the real experience of specialists and on the performance of sawmills. This makes it possible to compare percentages and calculate optimal averages.

In conifers, the following output is possible:

1. For unedged boards and other unedged materials during sawing, the yield will be 70%. This is the amount of material obtained during processing, the amount of waste will be 30%.
2. For edged material, when using sawmills at 63, 65, 75, there will be a lower yield of lumber, in the region of 45%. In band sawmills, the output is usually up to 55-60% of the finished material. If you apply the means to improve efficiency, then you can reach 70%, although this requires a lot of experience.
3. 70-75% lumber can be obtained from a sawmill, although with efficiency improvement methods it may well be 80-75%. But experience is required.

According to GOST 8486-86, for grade 0-3, the percentage of yield, excluding sorting, is approximately 70%.

Another 30% can be left for rejection of the finished material. Rejected material is not thrown away, it is used for the manufacture of other types of lumber, which allow the presence of a certain marriage.

Hardwood roundwood has a different yield percentage:

1. For unedged material - 60%.
2. For edged wood - up to 35-40%, since the curvature of the original hardwood forest is usually large.

The output can be increased, for this additional equipment is used. It can be a special multi-saw machine, an edge trimming machine, a slab machine. In this case, it will turn out to increase the yield of lumber by about 20%. The given percentage is given on the basis of data on the production of grade 0-4 boards. When sorting grades 0-1, the percentage of lumber production is 10%. To get a cube of finished hardwood edged material, it is necessary to cut 10 cubes of the original roundwood for sawing.

The output of lumber from roundwood can be different. It all depends on the original wood species used by the sawmill. Special measures to increase efficiency allow you to get a higher percentage than possible, but for this you need to have some work experience.

Sawing wood is a cycle of actions using a variety of technologies aimed at obtaining lumber from round timber suitable for further use in industry. The duration and labor intensity of the process depend on the chosen method of processing round timber, as well as the time of year.

Tool and equipment

Trunks and large-sized branches go into production. All material is divided into groups according to the thickness and presence of bark. Often, wood processing enterprises have workshops near the harvesting site, in which machines are installed for the initial processing of wood.

Manual debarking of the forest

The wood that has not passed the debarking stage can be used on the construction of floors or as a ridge beam in the corresponding interior, or as a supporting device during construction.

Industrial debarking

If another option for using the tree is planned, then sawing is carried out, resulting in the following segments:

• unedged and semi-edged (rough material from which the bases of the floor, walls or ceiling are mounted);
• edged (designed for finishing flooring).

The sawing can be carried out by a field organization that has all essential tool.

Tree sawing map

The rational use of the material is ensured by compliance with the sawing map. This allows you to reduce the cost due to waste, the percentage of which the card can significantly reduce. The used tools and types of forest processing equipment depend on the volume, desired quality and size of the finished lumber.

Most often use a circular saw and various machines:

• circular at the expense circular saw allows you to make precise cuts of various directions. Suitable for both professional and home use, perfectly copes with the diameter of the round timber above the average;
• chainsaw;
• machines for clean removal of bark;
• sawing for band sawmill makes it possible to process dense logs, is considered the most popular, since the output is high-quality material and a small amount of waste;
• disk machine: production of two-edged timber and unedged boards;
• a frame sawmill does not need a foundation, the technology with its use allows you to install equipment in close proximity to the cutting site;
• the thinner is processed by universal machines, the output gives high-quality building materials even from low-grade whips;
• sawing round timber at a large woodworking enterprise should be carried out with the largest amount of sawn timber, which differs from the rest in special quality and exact dimensions. For this purpose, special lines are installed for sawing.

At the sawmill they get a bar and edged board thanks to the cut logs up to 7m long and 15-80cm in diameter along the longitudinal line. The circular saw has one or more discs, it processes different diameters of the forest according to their number.

If at home it is necessary to process a small amount of wood, then you can use a regular chainsaw.

cutting wood

Before choosing a tool, you need to decide on the type of cut, focusing on the annual rings of the log. There are several types:

• radial (along the radius);
• tangential (the cut is parallel to one radius, touches the annual rings);
• the fibers are arranged parallel to the cut being made.

Among the cutting methods, the one that is most suitable for a particular case is selected:

1. Razval. Sawing wood in this way is carried out for deciduous trees with a small trunk thickness, it is considered the simplest processing. Exit: unedged elements and slabs.
2. If there is another woodworking machine, then it is possible to cut up to 65% of the material to produce edged boards of the same width. First, a two-edged timber and boards are sawn from the sides, and then a certain amount of edged lumber is obtained from the timber.
3. More specific methods are sector and segment sawing. The number of elements in the first method varies from 4 to 8, and depends on the thickness of the trunk. After separation, elements are sawn from each sector along a tangential or radial line. The second method begins with the exit of the beam from the central part, and boards are sawn from the side segments in a tangential direction.
4. For individual sawing of wood, the circular method is suitable. It is based on turning the log along the longitudinal line by 90° after each sawn board. This allows you to monitor the quality of wood and timely remove the affected areas of the trunk.

Handmade: chainsaw application

For home cutting of several trunks, it is not advisable to purchase a tool whose cost is several times higher than the price of finished products. If you have the necessary skill, then it is more efficient and cheaper to do the whole necessary work conventional chainsaw, or chain equipment powered by electricity. Of course, such work requires much more physical costs and time, but the price of the issue is significantly reduced.

Garden work needs pruning fruit trees, and also it becomes possible to additionally produce material for outbuildings, without resorting to the services of specialists, so that any prudent owner would prefer to buy a chainsaw. Most often, conifers are harvested for the home, and this tool does an excellent job of sawing them. Thanks to even trunks, it is easier to outline the cut lines, which increases the speed of work. Professionals, by the way, most often use a chainsaw, since it is more powerful than an electric one and you can use it anywhere, regardless of whether there is a cutting or sawing of power supplies at the site.

To work with a chainsaw on cutting logs, you will need such a device as a nozzle on the saw, as well as saw cut guides and base-trunk fixers. The nozzle in the form of a frame is attached to the tool so that it remains possible to adjust the distance between the chain and the frame itself. This is done to enable the output of finished lumber, different in thickness. For the role of the guide, you can take either a profile of the desired length, or a flat wooden plank with sufficient rigidity. A special chain is selected for the tool, designed to cut the trunk along. Its difference from the rest is in the teeth, sharpened at a certain angle.

Before starting work, it is necessary not only to prepare all the necessary tools. Regardless of whether a woodworking machine is intended for processing the trunk or hand fixture, the first step is to familiarize yourself with the cut map. This is done in order to minimize the percentage of waste, and increase the yield of useful products.

The first thing you need to worry about when ripping is the uniform density of the finished boards. To do this, a competent sawmiller directs the tool from the east side of the log to the west, or in the opposite direction. This is due to the greater density of round timber in its northern part than in the southern.

Next, the slab is removed from both sides with a chainsaw in such a way as to obtain a two-edged beam. It, in turn, is sawn in accordance with the sawing scheme chosen at the beginning of the work. The output gives an unedged board. If there is a certain percentage of defects in the trunk, then a circular cut is possible with the trunk turning at a right angle or 180 °.

Quantity of finished material, cut price

The output of useful material from coniferous and hardwood differs in percentage terms. For lumber obtained from coniferous trees, are characterized by the following indicators:

• provided that the operation is carried out by a professional and a sawmill is used, the percentage of finished wood will be the highest (80-85%);
• edged material, which is given by machines, averages 55-70%;
• unedged board when working with a chainsaw leaves up to 30% of waste.

The figures are given without taking into account the finished rejected wood, the amount of which can reach 30%. However, such material is used for products that allow a certain marriage.

Deciduous round timber gives 60% of the finished unedged wood and about 40% of the trimmed wood. This is due to the initial curvature of the round timber. You can increase the amount of products received: this will require woodworking machines of various kinds. A certain kind of fixture can increase the amount of lumber by 10-20%. For one cube of lumber, you will need about 10 cubes of hardwood round timber. Installation price additional equipment will pay off the cost of the finished wood. Special lines give more volume, but their use is advisable only on a large area. The average price of sawing wood at a conventional sawmill will be approximately 150-180 rubles per cubic meter of boards.

sawing map

The sawing map is a calculation of the optimal amount of finished lumber from one log. It can be calculated independently for each specific log diameter, or you can use a computer program that greatly facilitates the calculation, and the price of which is quite affordable.

Or the source can be a regular guide to sawmilling. The result is a table that is taken as a basis. The sawmill must always be oriented to its data, in order to obtain more lumber of any kind of wood.

All photos from the article

In this article we will talk about how cutting logs is performed on a band sawmill. In addition, we will consider what are the criteria for selecting one or another method of wood processing and how this affects the characteristics of finished lumber.

Methods for cutting logs to obtain various lumber have been developed and improved for a long time, since this is the only way to get an edged board, timber and other categories of similar products from a solid tree trunk.

For a long time to this day, wood processing methods have evolved, and in addition, new, more productive equipment has appeared that allows you to get the necessary lumber quickly and with a minimum amount of production waste.

Features of wood processing

The instruction for processing raw materials and obtaining sawn products consists of a number of technological operations, including longitudinal cutting of logs, sawn timber trimming and cutting to width, sorting by standard sizes, sorting by workmanship quality, drying and storage.

Each of these stages is important in terms of the quality of the finished product. But, it is cutting that is the most time-consuming and responsible stage, during which the main characteristics of finished lumber are formed.

Drawing up a plan for cutting logs into lumber (the choice of a suitable processing method) depends on the type of wood, on the standard sizes of raw materials, on the degree of humidity, on density and hardness, and on many other factors. Of course, the method of processing raw materials is largely determined based on the level of technical equipment of the enterprise.

Consider what equipment is used for industrial sawing of wood and what methods are relevant for each category of this equipment.

Equipment for cutting and features of its application

The following categories of equipment are used for longitudinal cutting of logs:

• Single band saws or circular (circular) saws are a traditional solution that has been used for a long time.
• The group of frame saws is a more advanced solution that allows you to significantly increase the productivity of raw material processing without compromising the quality of the finished product.

Let us consider in more detail the features of the use of the listed categories of equipment.

1. Individual sawing is a method in which single saws are used. In this case, only one cut can be obtained in one pass of the saw. Therefore, the entire tree trunk can be cut in several passes.

Important: The advantage of individual sawing is the independence of each subsequent cut from the previous one.
That is, sawing can be carried out in different planes.
As a result, it becomes possible to more rationally use certain properties of different parts of the log.

At the same time, this method is inefficient, and therefore not suitable for use in large woodworking enterprises.

1. Group sawing- this is a technological process during which a group of frame saws is used.
   advantage this method is that the log is cut completely in one pass. This saves time and, as a result, reduces the cost of production. But you need to remember that group sawing is performed in one plane.
   To date, the following categories of equipment for group sawing are most widely used:

• narrow-clear vertical frames, machines with circular saws, milling saws (diameter of processed raw materials from 14 to 22 cm).
• medium-light vertical frames (diameter from 24 to 48 cm)
• wide-clear vertical frames, double and quadruple band saw units (diameter of processed raw materials over 50 cm).

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Detailed description functions of the log cutting programs. We offer you an assistant that will increase the yield of wood by 10-15%, and the process of preparing cutting charts will speed up the process by 500-700%.

Pi2 program for cutting logs into boards of the same width and thickness.

Executing Pi2 produces the following output:
1. Technological maps for cutting logs.
2. Increasing sawing productivity by 10-15%.
3. Reducing the dependence of productivity and quality of sawing on the human factor.

"Reverse" calculations possible: the user specifies only the dimensions of the board, and the program proposes (calculates) the minimum size of the log that is needed to produce this board. You can sort the logs according to the size of the planks.
To choose the best cutting (highest output), do a lot of calculations. The calculation report is presented in Excel. It is convenient to import data into your accounting system.

Pitago (Pitago) - smart assistant engineer...

The wane point* is the distance in meters from the thick end of the log, starting from which a wane appears in the direction of the thin end due to the wane of the logs.

Pitago - completely online solution, you can use it on any device, including mobile phones and tablets.