DEVELOPMENT OF TECHNOLOGY FOR CUTTING OAK WOOD
Toropov A.S. , Sharapov E.S., Krasnova V.F., Toropov S.A.
(MarSTU, Yoshkar-Ola, RF)
Results of researches new technology of sawing up oak wood with ring defeats are presented.
Among the valuable tree species growing in the European territory of Russia, the most important economic value is the pedunculate oak ( Quercus robur L .). Its valuable wood is in unlimited demand.
According to the research results of P.M. Verkhunova and I.P. Kurnenkova, the oak forests of the Chuvash Republic are characterized by a large faut of forest stands. In particular, a defect in the structure of wood is very common - the inner sapwood of oak. The cause of internal sapwood is frost damage to the sapwood layers. The inner sapwood differs from the core in less resistance to decay. At the same time, subsequently, ring large-pitted rot develops in it (45.1 - 75.0% of forest stands are affected by sulfur-yellow tinder fungus Laetiporus sulphureus L. .), then turning into pink-brown prismatic rot, excluding the possibility of using raw materials. Quite often, several areas of ring lesions are found in oak wood (Fig. 1).
Figure 1 - Cross-section of an oak affected by sulfur-yellow tinder fungus
For this reason, oak wood growing on the territory of the Republic of Chuvashia, as a result of sanitary selective felling, is transferred to the category of illiquid. Manufacturers prefer to use expensive imported raw materials from the southern regions of our country, which increases the cost of transportation, and this entails a significant increase in the cost of finished products.
The technology developed by us makes it possible to rationally use illiquid oak wood with an increase in the quality of the output sawn timber. According to the new cutting method (Fig. 2) to round timber 1, having annular lesions of wood 2, is fixed for a healthy peripheral zone, the shape and parameters of the affected zone are determined and subjected to division according to the program, while obtaining sectors 3 with the affected zone 2 (division of timber into sectors in the longitudinal direction).
Figure 2 - Method for cutting round timber with ring-shaped wood lesions
Further, the obtained sectors 3 are based on one of the processing surfaces and the affected part is separated in the longitudinal direction along the boundaries of the affected layers parallel to the tangent at the intersection point of the generatrix of the timber and the bisector of the sector angle, resulting in a peripheral segment 5, the affected part 4 and the core part 6. The affected parts 4 are turned one relative to the other by 180 0 in the vertical plane and fastened together, and the core parts 6 are also turned 90 0 in the vertical plane and fastened together. Next, the peripheral segment 5 is cut to obtain high-quality lumber. After drying the blanks, it is possible to glue them together along the edge. In order to increase the strength of the connection in the workpieces, joinery elements are made. In order to obtain sawn products of different sizes in terms of thickness and quality, the blanks are sorted according to geometric parameters and quality characteristics.
The use of a new technology for cutting oak wood with ring lesions will allow rational use of low-quality wood resources.
Literature
1. Verkhunov, P.M. Variety-forming defects and commodity structure of oak forests of the Middle Volga region [Text] / P.M. Verkhunov, I.P. Kurnenkova // Forest inventory and forest management: Interuniversity. Sat. scientific tr. - Yoshkar-Ola.: MarGTU, 1997.- S. 72-78.
2. Vakin, A.T. Wood defects [Text] / A.T. Vakin, O.I. Poluboyarinov, V.A. Solovyov. – M.: Lesn. prom-st, 1980. - 112 p.
3. Alekseev, I.A. Forest commodity science with the basics of wood science [Text] / I.A. Alekseev, O.I. Poluboyarinov. - Yoshkar-Ola.: MarGTU, 2006. - 457 p.
lumber - materials from wood (beams, boards and bars) obtained by sawmilling. There are sawn timber of radial, tangential and mixed sawing. Lumber with sawn edges is called edged, with unsawn - unedged.
Large high-quality logs (these are logs from the bottom, butt of the tree) provide the most valuable lumber. When sawing such logs, it is necessary to determine the thickness of the resulting boards in order to maximize the volume and cost of the resulting material. Since the price of lumber depends on its thickness, and in addition, when sawing into thicker timber, less sawdust is produced, this decision has a serious impact on income. However, if the quality of the thick material is lower, even if the best edge is almost clean, then it will not be easy to sell it for a good price. The sawmiller should try to reduce the size of the sawn material when he sees that the quality of the wood is starting to decline.
If the log is good, it is unwise to produce large lumber and railroad ties from the center of the log. Because the price of a bar is always less than the price of a board.
For logs of high grades sawing in a circle is recommended. In fact, sawing with respect to the taper of the log, with the log angled so that the cut is parallel to the bark, is recommended for all "good" edges. The result will be pure wood throughout the length, more valuable pieces of lumber, and this will avoid the need to saw the clean wood later into short pieces. When you get to the low grade part of the log, go to the shape of the cant and minimize the operation of cutting the cant on the sides.
Strong, but low-quality logs should be sawn as quickly as possible. These logs are of little use - the profit is very small, or none at all, which means that these logs need to be removed from the machine the sooner the better. Any method of sawing is suitable here. Most often they are sawn on a beam, or simply sawed through. In this case, it is generally better to reduce log flips to absolute zero.
Weak logs provide such insignificant profits and such a huge risk of breaking the product that it is better not to deal with them at all.
Medium-quality logs can produce a significant amount of good lumber, and here a lot depends on the sawmiller, on how he will turn the log. Here the decision to rotate the log is critical to profit.
First you need to choose the worst part of the log and cut it without taking into account the run. But you can not cut too much on this side. For small logs, in general, you need to cut one layer, that is, saw through the entire length of the log once, or a layer and a short board, and then turn the log over to the opposite side.
Another way is to choose the best side of the log and start sawing taking into account the taper of the log. Then it is this part that is sawn for a long time before the log is turned over.
Lumber is sawn from one side until the sawmill expects the next board on that side of the log to be at least as good as the boards that can be obtained from the other side. There is an exception: if you start sawing from the worst side of the log, then you have to cut until you get a completely smooth cut surface in order to turn the log onto it. In other words, the good side of the log needs to be sawn deep, and on the bad side, a layer or layer and one board are simply removed.
If we take a log with a diameter of 60 cm, although this is true for all logs of any size, when sawing with a 180 ° turn, we get 8 boards that need to be further cut on the sides, and using a less efficient method, always turning to the adjacent edge, we get 13 such boards. This circumstance alone can already be a significant argument in favor of turning a log 180 °, especially for small enterprises. In addition, this way of sawing produces more wide boards, and they are usually more valuable. When flipping to the adjacent edge, 8 boards of tangential sawing are obtained, which are subject to strong warpage during drying. Further, if it is a walnut or red oak with a narrow sapwood, then with a 180-degree turn of the log we will get 10 boards with sapwood, with another method of turning - 13 boards. Sapwood causes problems with drying. And with a 180-degree turn of the log, the internal stress of the wood is removed, which as a result avoids cracks and cracks.
Turning over to the adjacent edge may be easier, but from an economic point of view and from the point of view of sawing safety, it is more beneficial to rotate the log by 180 °.
After sawing two opposite sides of the log, you need to move on to the third and fourth. As usual, the worst of these edges is sawn first, regardless of the taper of the log. However, a good quality edge should always be sawn parallel to the bark to increase the yield of good lumber from the log.
The width of the first layer when sawing from all four sides of the log is critical.
If the edge is of good quality, that is, the first sawn board can be classified as a good grade, then the minimum width of sawn timber should be 15-1 cm. Of course, this depends on the size of the log itself. To allow for further processing of the board, planing or even trimming on the sides, it is recommended that 15-1 cm, not 15 cm.
If the edge is of poor quality, then it makes sense to cut boards with a width of at least 10-1 cm. The length of such boards should be at least 1.2 m. In general, you need to produce boards of no less length on your sawmill.
When it comes to logs of frankly poor quality, it makes sense to saw them from the “belly” or from the “ears”, and not look for a good edge. The lugs are usually removed in 1 or 2 passes of the saw, revealing a smooth surface inside the log. Sawing from the “belly” requires more manipulation, and as a result you get several short but clean boards.
The beam has a number of advantages in comparison with thin boards. The lumber often has a beautiful wood pattern that customers love. When drying, it dries out half as much as boards (3% versus 6% for boards). Less cracking during drying. When the ambient humidity changes, the timber is more stable. When they cover the floor, it hardly wears out.
Also, when sawing a beam, the yield of a useful product from a log is 20% lower. Its production rate is much lower. It requires 15% more drying time. The beam dries out in thickness 2 times more than narrow boards. Sharp branches that remain in the timber, unlike round branches in boards, greatly reduce the strength of the material.
Radial called a cut, in which the cut 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. Radial cut boards are resistant to external influences, practically do not undergo deformation and have high wear resistance. The radial sawn board has a shrinkage ratio = 0.19% and a swelling ratio = 0.2%. These figures for radial sawn lumber are twice as good as for tangential sawn boards. For a radial sawn board, the process of shrinkage and swelling goes 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 arranged in width. Accordingly, a floorboard, a parquet board, an imitation of a beam, a block house, a lining of a radial cut has practically no gaps compared to similar products of a tangential cut. Since the output of radial sawn boards is 10 - 15% of the total volume, their cost is quite high.
Radial sawing of wood is a method of sawing a log in which all the fibers in the board go along the direction of the annual rings. When sawing radially, lumber has the best physical and mechanical properties. The strength and hardness of wood with a radial cut is higher than with a tangential cut.
The output of a radial sawn board is usually small (does not exceed 30%). On the UP-700 rip saws, the output of the radial sawn board reaches 60%. Such a high rate is achieved thanks to the cutting optimization system. Choosing among the optimization criteria the maximum exit of the board of the radial cut, the conditions of radiality and semi-radiality of the cut, the technologist determines the percentage of the exit of the radial board.
Radial sawing can be done on other equipment. But the percentage yield of a radial cut board on other equipment depends on how the operator cut the log. Usually this figure is much less than 50%. Due to the microprocessor control system and the optimization system on the UP-700, you can get the maximum possible number of radial sawn boards.
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| saw cut texture: 1 - tangential cut; 2 - radial cut; 3 - semi-radial cut. | ||
tangential a cut is called, in which the cut 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 wavy pattern of annual rings. Tangential sawn boards have higher shrinkage and swelling ratios, but are more affordable.
Sawing hardwood
The sawing operation includes decisions about board thickness, log flipping, and log taper compensation. It depends on many factors: the type of wood, the quality of the log, its dimensions, the design of the machine and the grade of lumber to be obtained. There are 3 standard cutting patterns:
Simple sawing
The log is sawn until its core is exposed, and then turned over 180° and finished sawn to the end. This is the fastest and easiest sawing method, yet with this method each piece of lumber needs to be trimmed at the sides. The lumber sawn in this way is somewhat wider and heavier, of lower quality and has a lot of waste. It is extremely susceptible to warping during drying. Therefore, simple sawing or sawing through is justified only in the case of very low quality logs, when all the above disadvantages are no longer particularly important.
circular sawing
When sawing in a circle, a cut is first made, and the log is turned over to a new edge, sawn, and turned over again, until at least 5 turns have occurred. From a financial point of view, this is the best way for medium and high quality logs, although at the same time, at some sawmills, it is difficult to turn the logs like this, and daily productivity will be low. Of course, a machine with hydraulics solves this problem.
Sawing timber
Cant sawing maximizes sawmill productivity (number of boards per day) and is typically used in industry for medium to large logs. In this case, the log is sawn first as in circular sawing, but the central part of the log, which may have dimensions of 18x23 or 25x25 and so on, is either transferred to another machine along the production line or sold as a large and heavy cant. Basically, medium and low quality logs are sawn in this way, when it is impossible to get valuable lumber from the central part of the log. Thus, time and effort are saved in the production of a product of not very high quality and therefore not very high price.
Deciding on which side of the log to start sawing, which cut surface to open first, is the most important part of sawing. We divide the log into 4 faces, each of which extends along the entire length of the log and occupies a certain part of its circumference. The choice of the first face is determined by the position of all others.
When sawing in a circle and sawing a bar, two basic rules apply:
The worst side of the log is sawn first, regardless of the taper of the log. Accounting for log run means raising or tilting the log so that the saw cuts parallel to the bark. Since this is the worst part of the log, it means that it will make short boards and a lot of slabs. Since we do not take into account the taper of the log, this gives us the opportunity to saw from the opposite, better side of the log parallel to the bark, without lifting or tilting the log. This means that more boards of high quality will come out of this best part of the log, moreover, the same length as the length of the log.
First cut the best edge of the tree, taking into account the taper of the log. This means that the log must be raised or tilted so that the first cut is made parallel to the bark.
The end result of both methods will be about the same, but the second method has one advantage. In this case, it is easier for the sawmiller to rotate the log, because the open edge is the cleanest, there are no defects on it. In the case of the first rule, the best part of the tree is the part opposite the open face. It is not visible, and it is impossible to accurately rotate the log. Usually, if the wood is of good quality, then both rules work almost the same. But if you encounter a worse log, it is better to use the second rule.
Sawing soft wood
Many of the methods used when sawing hardwood are also suitable for softwoods. But there are also some differences. Of course, safety considerations must take precedence over the desire to produce as much product as possible.
Position the log so that when sawing, minor defects in the material are inside the lumber, of course, if these defects are not so serious as to affect the strength of the final product. If possible, cut so that all branches and defects are located on one side of the lumber, while the other side remains clean. True, in the case of building materials, a clean surface does not affect the final price of the product. But large branches or defects can affect the strength of the structure.
Pick the worst side of the log and start sawing from there, producing short lumber. The first lumber will be the worst lumber and therefore must be short in order to sell.
After the log has been sawn from the bad edge along the entire length of the log, it is necessary to move to the opposite edge, and cut parallel to the bark. With a good edge, the width of the sawn board should be at least 15 cm. On smaller logs less than 30 cm in diameter, the first board should be 10 cm wide. Huge logs will have fewer internal defects and therefore do not need to be converted to large building structures.
You should always turn the log from one side to another if the lumber from the new side is of better quality than the one that was just sawn.
Logs from waste. It is necessary to cut the "ears" in one pass of the saw, then turn the log over to the "belly", perhaps at least a few short boards can be made from it.
LesOpt Lider offers decorative oil treatment of lumber (calm lining, block house, planken, floor and terrace boards) and molded products. Under decorative processing it is necessary to understand professional painting by spraying. Our company provides services: painting, varnishing, brushing, cutting and cutting lumber, packaging and delivery in Moscow. LesOpt Leader specialists will provide you with professional advice on carrying out joinery in Moscow and carry out the necessary work quickly and at a reasonable price. All operations are carried out by professional carpenters, which avoids unwanted effects. Trust LesOpt Lider professionals!
Oil coating of wood
To provide wood with durability, fire resistance, protection against pests, mold and fungus and just to give an attractive look, the wood is impregnated with oil. This type of wood processing is considered the most popular and for good reason. Firstly, being deeply absorbed into the wood structure, the oil reliably protects against high humidity and any contamination. It is known that over time, constant contact with water can destroy valuable rock. Secondly, the oil provides protection against cracking and flaking, in addition, it is completely environmentally friendly. Thirdly, this procedure gives the wood a more natural look and hides various surface defects.
You can order from us impregnation of wood with oil, Qualified craftsmen with experience will complete an order of any complexity in a short time.
The cost of this service is from 300 rubles per m2.
From 300.0 Р
Wood brushing
One of the fashion trends today is wood brushing. This process is also called artificial aging. Those. If you want to bring a touch of aristocracy and make the atmosphere in the house warmer and more comfortable, then this service is just right for you. The labor-intensive procedure of brushing involves the removal of the top layer - soft wood fibers, after which a pronounced, three-dimensional texture pattern remains. Brushing is done using special metal brushes by mechanical action.
In addition to improving appearance, brushing has a number of other benefits. It is resistant to mechanical damage, ultraviolet and humid environments.
Our specialists will carry out this procedure with high quality faux texturing and your wood will become uniquely refined and noble.
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Cutting plywood to size
We offer you a service such as cut plywood to size. Our concern is to provide customers with maximum comfort and convenience, therefore, after ordering lumber, you are given an excellent opportunity for high-quality cutting to required dimensions and with high precision.
The process of sawing plywood is a rather delicate matter, because it requires certain experience and professional equipment. Therefore, it is better to entrust this responsible procedure to specialists who will fulfill the order at the highest level.
The cost of this service is from 30 rubles per m / p.
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Cutting wood according to the customer's dimensions
In LesOpt Leader, you can order the service of sawing boards, timber according to the size of the client. Cutting boards, timber It is produced both in standard sizes and individually, depending on the requirements of the customer.
Benefits of working with us:
- cutting is carried out on modern high-precision equipment;
- operational work regardless of the given volumes;
- affordable cost of the service;
- Individual approach to each client.
Our specialists approach with high accuracy and thoroughness to the execution of the order according to cutting lumber. We guarantee each client impeccable quality, the shortest possible time, as well as an acceptable cut service cost.
The cost of this service is from 500 rubles
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Timber under the order
Lesopt Leader offers its customers the opportunity to purchase lumber on order, including their production by individual sizes. The key to success in construction and finishing works lies in the high quality of materials, competent calculation of dimensions and the right type of wood. All this will help you to do our qualified staff and excellent technical equipment. Thanks to our own sawmill, we are able to offer absolutely any lumber and related products. In addition, with the help of modern and high-precision equipment, Lesopt Leader:
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Thermowood and thermowood production
Thermowood and heat-treated wood products are gaining more and more popularity. After all, as a result of heat treatment of wood, it acquires new properties and an attractive appearance, especially a thermoboard made of thermoash and thermopine. After processing, the thermal wood to buy or order products from which you can in our carpentry workshop becomes stronger, more durable, the risk of exposure to various types of fungi, mold, pests is reduced, and when excess moisture gets in, it does not swell or crack.
Many species of wood are subjected to the heat treatment process, the thermoboard retains its useful characteristics, this is especially true for terraced thermowood, the scope of this material is expanding, while the price of thermowood, as well as the price of thermoboard, remains affordable. Thermo-ash is very popular because it has a rich texture and aesthetic appearance that surpasses many exotic wood species. Thermopine is used for such purposes as the manufacture of planken and facade thermal boards, and also serves as a material for cladding the walls of houses, baths and saunas. In the Lesopt Leader warehouse, you can also pick up various heat-treated species: thermo-ash, thermo-pine, thermo-oak, thermo-larch, thermo-aspen, thermo-linden, thermo-abash and many other species.
Oak is a very popular material that is widely used:
- Construction.
- Finishing work.
- Creation of furniture.
- Production of art objects and souvenirs.
Naturally, not just felled and sawn wood is used in the work, but processed and qualitatively dried material. This is a prerequisite to avoid future cracking, changes in the shape and size of the product. Oak, which is used in construction or furniture business, must have certain physical and mechanical properties.
Therefore, when sawing is completed, the question arises: “ How to dry oak". We will answer it in this article.
Features of oak wood: what should be the result of drying
Oak lumber is quite capricious, it is difficult to dry naturally. It is not enough just to leave the stack under a canopy or in the open sun in order to get the desired result after a certain time.
Before how to dry oak boards, you need to understand the features of the material:
- Oak wood is subject to drying. This means that when the moisture level falls below a critical level, internal and external cracks can form.
- The hardest thing to dry is freshly sawn oak, the moisture content of which exceeds 25%.
- Temperatures above 55 degrees at the initial stages of drying are unacceptable. This leads to the collapse of woody capillaries, that is, to the appearance of multiple internal cracks.
- It is not recommended to send freshly sawn material with a moisture content above 40% to dry.
- Proper drying of oak requires maintaining a certain level of temperature and humidity.
Features of drying oak wood are such that in order to obtain a quality material without defects with a certain percentage of moisture, it is necessary to draw up a preliminary plan for this procedure, use special tools.
There are several tasks for drying oak:
- Shrinkage with warning of changes in linear dimensions. Here, the humidity is reduced to 30%.
- Shrinkage to transport humidity of 20-22%.
- Full volume drying for direct use. The humidity level should be 6-12%.
Oak drying methods: chamber and tubeless technique
From the foregoing, it is obvious that obtaining wood from a freshly cut oak that meets all the necessary parameters is a laborious and lengthy process.
There are many ways to reduce the humidity of boards, logs and beams, but all of them can be divided into two broad categories:
- Chamberless (atmospheric) drying.
- Chamber drying.
Atmospheric drying is ideally the most affordable and natural way to reduce moisture levels. The technique has been used in sawmills and woodworking industries for centuries. It is believed that a naturally dried tree is of the highest quality and can be used for decades without changing its original qualities. But the method has one significant drawback - prolongation in time.
Since modern life is very dynamic, buyers are interested in acquiring material as quickly as possible. Logging companies, in turn, prefer to sell wood as soon as possible. Therefore, in the XIX-XX centuries, many techniques were invented using electrical energy. Chamber drying is carried out in convective chambers, the condensation method and vacuum drying are also used. 
All work is carried out in industrial conditions, as a rule, are divided into the following stages:
- Warming up
- Drying directly.
- Cooling, obtaining a predetermined humidity threshold.
Chamber drying is similar to repeatedly accelerated atmospheric drying, the desired result is achieved many times faster. But the disadvantage is the high cost of the procedure. It is necessary to use expensive equipment, most often it is possible only in industrial conditions.
Fortunately, infrared dryers have appeared not so long ago, which allow reducing the time of atmospheric drying, obtaining the desired result in a time comparable to chamber processing. At the same time, all features of drying oak wood, the material does not experience aggressive action that destroys the structure. At the end of the process, the humidity reaches the required level.
Infrared oak drying: the advantages of the modern method
Proper drying of oak Now it has become possible even at home. Infrared dryers manufactured under the FlexiHIT brand have a cassette form factor, are easily placed inside stacks, and can also be used to dry small pieces of material. In this case, the volume of wood does not matter, it is enough to use the required number of dryers and arrange them correctly. The result is achieved in 3-7 days.
The properties of infrared-dried oak correspond to those of atmospheric-dried wood:
- The material has a specified moisture content.
- The fibers do not warp, cracks and stressed areas do not form.
- The appearance matches that of naturally dried oak.
It is noteworthy that everyone can use IR dryers, you do not need to have special skills to get the result. The equipment operates from a conventional electrical network, while consuming very little. Drying one cubic meter of wood requires no more than 200-400 kW.
To check the humidity, it is enough to use a moisture meter, when the required indicator is reached, the infrared dryers turn off. Oak can immediately be used for its intended purpose.
Oak wood is quite capricious when drying, in order to get the best result in the shortest possible time, it is better to prefer tubeless drying in combination with IR dryers.