Sawing frozen wood on a band saw. The work of a band sawmill: sawing logs into boards. Band sawmill Taiga T3 and its features How to cut birch on a band sawmill

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Sawn logs are boards,. The task of competent and efficient sawing of trunks is extremely relevant for independent or industrial logging, in addition, knowing the basics will help you choose the right lumber.

We will look at the main points regarding this topic, and tell you how to properly cut a log into band sawmill.

sawing logs

The main task

Important! The sawing scheme is selected in accordance with the quality of raw materials, the purpose of the board and the capabilities of the equipment.

Sawing tool

Logging is done with a special tool. For normal work by today's standards, you need a special machine for cutting logs with your own hands, which is called a sawmill.

There are two types of sawmills: disc and band sawmills. Disk use circular saws and are considered less effective, since they have a large cut thickness (from 6 to 9 mm), lower accuracy and depth.

The band sawmill is equipped with a different system: the saw is a band worn on rotating rollers. The cut thickness is approximately 1.5 - 3 mm, which is quite economical in terms of chip removal.

Modern models are characterized by high accuracy and productivity, they are automated and have a tilting mechanism for lifting and turning logs in case of circular sawing or sawing timber.

Using a chainsaw, you can only cut a log in half, but if you use a special frame, you can dissolve the log into boards right in the forest.

Important! Band sawmill is considered the most efficient and cost-effective.

Conclusion

Sawing a log is considered one of the most complex and important tasks in logging and lumber production. The quality of products and the income of the enterprise depend on the chosen scheme, well-designed work procedure and tool preparation.

The video in this article will tell you about the types of sawmills and how to cut wood.

For a small woodworking industry specializing in sawing wood into boards and beams, the optimal equipment to use is. It has good productivity, allows you to dissolve large-sized trunks into lumber. But in order for the equipment to work with full efficiency during the work, you need to know how to cut on a band sawmill. Taking into account certain recommendations and features of the operation of such a unit will allow you to avoid problems and get high-quality business material at the output.

The process of sawing timber with this sawmill comes down to the fact that the log is placed and fixed on a special frame, which also acts as a guide. A frame with a cutting tool mounted on it, driven by an electric motor or internal combustion engine, moves along the barrel along the rails.

Preparatory stage

One of the main conditions for the normal operation of the equipment is the preparatory work before sawing on a band sawmill. And they include:

• cleaning the sawn log from dirt and sand;
• evaluation of the tree (breed, humidity);
• selection of a saw (shape, profile, sharpening angles of teeth) depending on the material being cut;
• correct performance of adjustment work (tensioning of the cutting element, drive belts).

Proper preparatory work will allow you to quickly saw the wood with proper quality.

An important factor for normal sawing is correct sharpening and saw spreading. These works should be carried out only on special machines. A well-sharpened saw with a properly selected tooth profile will provide high speed work and a clean cut.

Attention should be paid to the adjustment of the cutting blade. Correctly tensioned tape will ensure an even cut. Any violation of the tension will lead to a "waviness" of the surface of the boards, or to a rush of the cutting tool.

The more sand and dirt on the wood, the faster the saw will become dull, which will greatly affect the performance of the equipment. Therefore, it is better to prepare the material before sawing, as well as to sharpen and set the cutting tool in a timely manner.

sawing process

In the process of sawing, it is important to ensure a uniform speed of movement of the bed along the log. This will eliminate the possibility of idle tape movement and ensure maximum productivity.

Before sawing wood with a high resin content on a band sawmill, care should be taken to ensure that water or cleaning solution is supplied to the cutting area. This will prevent sticking of the teeth and ensure a good cutting speed.

After each pass, you should evaluate the quality of the cut and make sure that there is no “waviness”, and only then continue to cut the log. This will allow you to immediately identify problems with the configuration of the equipment and eliminate them in a timely manner.

Periodically, it is necessary to clean the moving elements of the sawmill from sawdust. This will eliminate unnecessary vibrations during the operation of the unit, which may affect the quality of sawing, and will also extend the life of the units.

In general, sawing on a band sawmill is not difficult, the main thing is to fully adhere to the manufacturer's recommendations regarding operation. should not be neglected and preparatory work, because the performance of the unit directly depends on them.

Find out from which part of the trunk they are cutboards or timberit is possible according to the pattern of growth rings, looking at their end, as well as by the number of knots on the boards or bars. The butt part of the trunk is always thicker than the top part and, as a rule, does not have branches, that is, it contains better quality wood.

From the middle part of the whip, the so-called technological raw wood is obtained - wood supplied to the mechanical (for chipboard production, fiberboard) or chemical (for example, for hydrolysis production) processing. The remaining butt part of the whip is sawn into two or three parts, which are fed to sawmills.

At sawmills, lumber is produced from logs by sawing them parallel to the longitudinal axis.

Among lumber, there are:

timber (width and thickness more than 100 mm)

segmented timber or quarters (obtained from a log sawn into four pieces)

bars (thickness up to 100 mm and width no more than double thickness)

Boards (thickness up to 100 mm, width more than double thickness)

obapol - side parts of the log

slats - thin boards and bars cut during longitudinal sawing

In addition to the listed basic lumber, there are also so-called semi-finished products, in particular, grooved and profiled boards, plinth and other molded products.

The thickness of the boards coming out of the saw frame is determined by the distance between the blades of the saw frame

1 - a beam is cut out of logs from heartwood;
2 - upon receipt of half beams, the log is sawn along the longitudinal axis;
3 - upon receipt of segmented bars, the log is sawn along the longitudinal axis crosswise;
4 - during group sawing (tossed), unedged boards are obtained in one pass of a log through a sawmill frame;
5 - in case of individual sawing with a bar, during the first pass through the frame, a two-edged beam, slabs and side boards are obtained;
6 - the most difficult is the radial sawing of a log, in which floorboards with vertically arranged annual rings;
7 - during the second pass, the two-edged timber is rotated by 90 ° and sawn into

Edged boards, separating side wane from it;
8 - for boards with horizontally arranged growth rings, the front side is called the side facing the core (core), and the back side is the side facing the sapwood (peripheral part of the trunk)

1. The outer layer of the bark, which protects the tree from cold and heat, and therefore from intense evaporation of moisture.
2. Through the inner layer of the bark (bast), the tree receives the necessary for its development nutrients. In the process of tree growth, the bast dies off, joining the outer layer of the bark.
3. Between the bast and the actual wood there is a cambium, which ensures the growth of the tree in thickness and the formation of growth rings.
4. Sapwood - external, a layer of active wood adjacent to the cambium and nourishing the tree with moisture. The older inner layers of sapwood are gradually receding towards the heartwood.
5. The internal dead layers of wood, no longer nourished by moisture, form the core (core), which, due to its strength, is the bearing and supporting core of the tree

Many masters have developed their own methods of wood processing, many years of experience with machines and makes it possible to significantly reduce the process. To get high-quality material, sawing on a band sawmill is necessary, taking into account all factors, observing the rules for operating the device.

Calculation features

The log is installed in the guide rollers with its fixation in the clamps. The amount of material obtained is calculated based on the diameter of the log. The correct calculation of the type and quantity of material also affects its quality.

An experienced sawmiller, having looked at the log, is already able to determine all the parameters of the future material, immediately find the butt and top of the log. The diameter of the butt is larger than the top. The thickness of the slab will depend on the accuracy of the calculation.

The diameter of the log must be measured from the top. Further actions of the wizard:

• There are practically no perfectly straight trunks. Therefore, it is necessary to carefully examine all the bends, bulges.
• Rotate the log so that the minimum amount of waste in the form of a slab is obtained.
• When installing a log, make sure that it moves freely in the guides.
• On the ruler of the sawmill, set the dimension according to the diameter of the log plus the maximum height of the bulge.
• The size of the bulge is determined from the difference in the diameter of the butt and top.
• The tape measure measures the size of the highest part, from the result obtained, the countdown of the dimensions of the material begins.
• The master must take into account the size of the cut 2-5 mm.

log turning

When the remaining height of the log approaches the desired size, it is turned over. If you need to get a beam with a thickness of 150 mm, the sawn width and the remaining height of the log should be slightly larger than this size, taking into account the slab.

When the log is turned over, the remaining height after the cut is made is measured, and the material is calculated before using this dimension completely.

Calculation example:

• The rest of the log height after cutting is 270 mm. The goal is to get a beam with a thickness of 150 mm: 270–150 \u003d 120 mm.
• From 120 mm it is necessary to obtain a block of 50 mm: 120–60–3=57 mm. The value of 3 mm is given for propyl.
• Tesina 25 mm: 67–25–3 = 40 mm.
• Podgorbyl 25 mm: 40–25–3=12 mm.
• Slab 12 mm.

Further obtaining of lumber is achieved by turning the log at an angle of 90 degrees and similar calculations. One of the common mistakes is not taking into account the allowance for cut or adding more times. The master needs to be careful.

Sawing technology

The sawing technology is selected taking into account the type of wood, the size of the log, design features sawmills.

Quality of raw material

The cutting efficiency depends on the quality of the raw material. First you need to evaluate the wood, sort the logs. Sorting is carried out according to the appearance of the log. Main signs:

• curvature;
• the volume of the false nucleus;
• number of knots;
• diameter.

The log is divided into 4 equal sides. A facet that does not have knots, cracks, rot, scars, chips, or damage from insects is considered clean. This results in the highest quality lumber.

Logs intended for sawing must be stored in accordance with the requirements. The sooner after cutting the tree the log gets into sawing, the easier it is to work with it. In dried raw materials, the saw can give a wave, and the thickness of the boards will change. The most valuable wood is outside the log, quality drops towards the center.

sawing methods

In the process of sawing, it is necessary to take into account the thickness of the board, the compensation of the taper, the flip of the log. Craftsmen can cut on a band sawmill in three ways.

Simple sawing

The log is subject to sawing to the end with the receipt of unedged boards, but the coup is not performed. The method is simple and fast, but has disadvantages. The resulting boards must then be cut from the sides.

Lumber comes out of poor quality with a lot of waste. The central boards crack easily, the method is suitable for working with low-grade wood.

circular sawing

Having made a cut, the sawyer turns the log over to another side, and so on in a circle to the remaining central part. For medium and higher grades of wood raw materials, the method is the best, but it is difficult to turn the log over at individual sawmills. Suitable for sawmills with hydraulics.

Sawing timber

The beginning of the cut is made in a circle, and the central part is left in the form of a certain size of the beam. Sawing timber ensures maximum productivity of the sawmill, the method is used for sawing medium and low grade logs.

First cut

It is important to choose the edge of the sawn wood to start processing. When sawing timber and circular processing, craftsmen use 2 methods.

The worst side is to be cut first, the taper of the log is not taken into account. Taking into account such a feature means tilting, raising the log so that the saw runs parallel to the bark. Short boards and a large amount of slabs will come out of this part.

Since the taper is not taken into account, from the best edge of the log, the sawing will go parallel to the bark without tilting and lifting, this approach will allow you to get the maximum of long boards of good quality.

Start by sawing the best side of the log, but take into account the taper. That is, set the log so that the saw is directed parallel to the bark.

The result will be the same, but in the second method it is easier for the sawmiller to choose the best edge, since it is visible. In the first method, the best part is hidden and inaccuracies are possible when installing the log. If the wood being cut is of high quality, both methods work in the same way. With raw materials of lower quality, it is better to use the second method.

log flip

If the turn is made by 180 degrees, unedged boards are obtained, requiring additional processing from the sides, and then the half-beam is sawn into an edged board.

With a turn of 90 degrees, unedged and semi-edged boards are obtained with the need to trim from one side. The 180° flip sawing method will produce more valuable wide boards. But if the edge trimming machine is equipped with only one saw, 90 degree flipping is convenient.

After sawing opposite edges, the worst of the remaining faces is cut first, but this option does not take into account the taper. But the high quality edge must be sawn parallel to the bark, which increases the yield of quality lumber.

Common mistakes and fixes

Masters are aware of a number of situations that adversely affect the material processing process.

When entering the material, the saw jumps up, but after that it works normally, at the end the power drops. The reason is often a large sharpening angle of the teeth, it must be reduced by 5 degrees.

Entering the wood, the saw rises, then the craftsmen get a curved board. The reason is that the sharpening angle exceeds the norm, and the wiring is insufficient. It is necessary to increase the sharpening angle by 4-6 degrees, and slightly increase the divorce.

After the dives, the saw goes smoothly, the sawmill gives several reasons: blunting of the cutting blade, a small sharpening angle. If the shape of the tooth corresponds to the standard, it is necessary to increase the sharpening angle.

The saw comes with constant dives. Small sharpening angle with insufficient wiring.

There is a large amount of sawdust on the surface of the boards, the setting of the teeth is increased.

Sawdust hot and pressed - underestimated divorce.

The cut is obtained in the form of a wave. If the saw is quite sharp, then the wiring is insufficient. Too little setting sometimes leads to saw blade breakage.

The fabric is cracking at its trailing edge. The rear stops of the rollers, in which the log lies, are far from the trailing edge. It is necessary to set the distance less than 0.3 mm.

Rolling sawdust on the saw blade. Small set of teeth, you need to increase the set.

sawdust rolling on inner surface teeth, they are not on the canvas. Poor tooth sharpening (high feed rate, excessive metal removal). Additional reasons - the sharpening angle is large, the saw was used after the blade was blunted.

After sharpening at the cavity of the tooth, the blade cracks. The geometry of the tooth is broken or the stone for sharpening is carelessly refueled.

Setting up a sawmill

Choice of coolant

Sawing on a band saw with water for lubrication is not correct. It is better not to use lubricant until the sawdust “runs” on the saw. If this happens, the optimal treatment is: 1/2 chainsaw tire lubricating oil, 1/2 diesel oil. The mixture is applied on both sides of the saw blade, but the amount of cooling solution is small.

Such a lubricant will extend the life of the sawmill pulleys and reduce the number of boards with traces of flowering.

Releasing tension

The cloth in the process of sawing is heated, which is why it stretches in length. After cooling, the desire for compression begins. At this point, overload occurs due to excess tension, cracks may appear.

The blade remembers the shape of the pulleys, deformation of the pulley belts occurs, which can lead to vibration of the blade. The hump on the belts is jammed, which ensures self-centering of the saw. When you stop sawing, the tension on the saw must be removed.

Band saw wiring

The optimal wiring is considered when between the saw blade and the sawn wood is a mixture of 2/3 sawdust and 1/3 air. If 80% sawdust is thrown out, the saw is set correctly.

In the presence of a lot of loose sawdust on the cut, and scratches on the surface of the board, the saw spread is more than necessary. The saw at the same time functions jerkily. With insufficient divorce, hot sawdust, tightly pressed, will remain on the surface of the boards during the sawing process, this situation has a detrimental effect on the saw. And after cutting the wood, waves will remain on the material.

Before sawing, the logs are sorted by diameter:

• For a larger diameter, the divorce increases, but it is performed only on 1/3 of the tooth from above.
• For soft wood, the divorce should be increased, sharpening should be done after preparing the equipment with the obligatory observance of the shape of the tooth.

The indicator of the divorce device works in a busy mode and often goes astray, therefore it is necessary to constantly check it.

Sawing speed

Increasing the sawing speed will result in a cleaner cut, but the life of the saw will be shortened. If the cut quality drops, the feed rate must be reduced. For the initial 5 minutes, the equipment operation indicator should not be more than 1/2 of the maximum value.

Preparation for work

During operation, the sawmill requires adjustment, verification of all its important components. The most significant part of the device is band saws.

Before starting work, you must:

• Check whether parts and screw connections are securely fastened.
• Lubricate rubbing surfaces.
• Check the reliability of grounding.
• Turn on the electric motor at idle, check how the belt moves.
• Check the installation of the band saw, adjusting if necessary.
• To reduce the saw blade deflection, move the left roller 5–10 cm from the side edges of the tree.
• raise band saw over the log and check its reverse motion.
• Check the fastening of the protective covers of the saw, gear, wedge-repair gear.

Video: Cutting methods

For processing logs on a band sawmill, it is necessary to adhere to the accepted technology. In this way, you can get the maximum quality materials- boards and beams. But first you should familiarize yourself with the basic rules of cutting.

Types of sawing wood

At the first stage, a carriage is formed from a log. To do this, cuts are made on its two sides. In some cases, processing is performed on four sides. A map of the band cut of the workpiece is preliminarily drawn up, on which the dimensions of the components are indicated.

The determining parameter when choosing a scheme is the direction of processing the log. In particular, the movement of the cutting edge relative to annual rings. According to this, lumber of various qualities is formed, which has a unique appearance. Not only their aesthetic qualities depend on this, but also the price.

There are the following types of cuts:

• tangential. The cut is made tangentially relative to the annual rings. As a result, oblong patterns in the form of arches, rings are formed on the surface;
• radial. For its implementation, perpendicular processing along the annual rings is necessary. A feature is a uniform pattern;
• transverse. Processing occurs across the fibers, the cut pattern is an even cut of annual rings;
• rustic. It can be done at any angle, contains a certain amount of knots, sapwood or other similar defects.

Often in the woodworking industry, waste from band sawing of logs is used - slab. On the one hand, a flat plane, and the other remains unfinished.

For the most accurate cutting, it is recommended to use special programs. They take into account not only the dimensions source material but also the type of wood.

Sawing on a sawmill with a log rotation of 180 °

To form the maximum number of boards, it is recommended to use a technology in which some of the tape processing processes are rotated by 180°. This allows you to achieve the maximum amount of lumber with various types cuts.

The principle of processing is to make initial cuts along the edges of the log, which are at an angle of 90 ° relative to each other. They will serve as the basis for further tape cutting. Works are carried out on equipment with a vertical arrangement of cutting elements. The diameter of the trunk must be at least 26 centimeters.

Step by step workflow.

1. Processing of the side with the cut edge part. The result is two boards.
2. Turning the workpiece by 90°. The cut is made from the opposite side. The number of products varies from 3 to 4.
3. Repeated 90° turn. The main part of the source material is being processed. Depending on the planned ones, 7-8 blanks can be obtained.

Despite all their positive traits, this method has one significant drawback - the low production rate. It is recommended to use it on equipment that has a block for automatically changing the position of the log relative to the cutting part of the machine.

A detailed scheme is most often used for the manufacture of rustic boards, which are subject to reduced quality requirements.

Sawing on a sawmill with a log rotation of 90 °

For the manufacture of tangential and radial boards, it is recommended to use a different technique. It consists in systematic band processing of logs with simultaneous analysis of defects. Thus, products of the required quality can be obtained.

After delimbing, the workpiece is placed on the feed frame sawing machine. Then you need to do the following.

1. Removal of the primary slab. It is carried out until the width of the base is 110-115 mm.
2. Removing unedged boards with a thickness of about 28 mm.
3. If the number of defects on the surface exceeds the required level, the material is rotated by 90°. If the quality of the board is high enough, the next one is cut off.
4. Repetition of the operation.

A similar technique is applicable for processing installations that have one cutting surface or have the function of temporarily dismantling the rest.

With a sufficiently large number of defects, it is possible not to postpone the workpiece, but to perform its processing using the 180° turn method.

The above tape processing technique can be applied to create any configuration of wood products. Often, the core area is used to form a beam, and the remaining parts are used to make boards. But there may be exceptions - it all depends on the required shape of the blanks.

The quality of work is affected by the current state of the sawmill, the level of saw sharpening and processing speed. These factors must be taken into account before production process. If necessary, preventive maintenance or repair of equipment is carried out.

The video shows the method of sawing logs on a homemade band sawmill: