Some materials even over time are popular with consumers. This gives the entrepreneur every chance to launch his own profitable business, producing products whose technology has been developed over the years. Pay attention to the manufacture of fiberboard. The enterprise will require impressive costs, but it is profitable to open a fiberboard production in Russia, since investments pay off quite quickly.

Our business valuation:

Starting investments - from 3,000,000 rubles.

Market saturation is average.

The complexity of starting a business is 7/10.

Fibreboard (Fibreboard) is a material in the form of sheets, for the manufacture of which wood raw materials are used. It is actively used as a raw material in furniture factories, construction sites. To minimize financial risks, you can open a mini-factory for the production of fiberboard, rather than a powerful processing plant. Analyze the sales market and draw up a business project to plan further actions. This direction is attractive to the entrepreneur for several reasons:

• An extensive sales market will allow you to quickly find interested customers.
• Simple technology makes it possible to understand the process in the shortest possible time.
• The raw materials used are inexpensive.
• Low competition in this area will contribute to the rapid development of a young enterprise.

Fiberboard manufacturing technology

To obtain fiberboard boards, waste from woodworking enterprises is used. To establish an uninterrupted supply of raw materials, arrange with several sawmills. It’s great if you can find a production facility nearby - it’s really possible to reduce variable costs when starting a business. If dry fiberboard production is introduced in the workshop, synthetic resin will be required.

To give the final material strength and moisture resistance, additional raw materials for fiberboard are used - precipitators, oil or paraffin emulsions. They can be purchased immediately in large quantities.

In general, the fiberboard production technology is carried out in several stages:

• preparation and dosing of components,
• sheet forming,
• material pressing,
• cooling,
• cutting sheets according to specified dimensions,
• sheet sanding,
• packaging and storage.

If you are going to buy whole wood, and not chips, you have to pre-process the raw material - grind it to a certain fraction size and steam it. These are additional costs for the purchase of equipment - it will be much easier for novice entrepreneurs to bring “ready-made” sawdust into the workshop.

Before purchasing equipment, consider fiberboard production methods and choose the best option. In practice, 2 methods are used:

• Wet manufacturing. The plate is formed in the aquatic environment on a special lattice substrate. "Semi-finished products" are then pressed under the influence of elevated temperature. All moisture evaporates and the material becomes dense. For a fiberboard sheet produced wet way, one side is ribbed.
• Dry production. Formation of the sheet is carried out without exposure to moisture. Artificial resins are used to glue wood chips. The mixture is mixed and pressed at elevated temperature under pressure. The finished product is then removed from the mold and further processed - cut and polished.

The production of fiberboard by the wet method is more popular among Russian manufacturers, since it is simple. But in Europe, this technique has already been left in the past, since high water consumption increases variable costs.

Technical equipment of the workshop

The fibreboard production line is the most impressive item of the planned investment. The quality of the manufactured products will also depend on the quality of the purchased equipment. The line includes the following machines:

• dispensers,
• mixers,
• forming machines with molds,
• sheet grinding machine,
• Grinder.

This is a list of the main equipment. To purchase everything you need, you will need at least 2,000,000 rubles. But in this way it will not be possible to fully automate the process - many operations will have to be done manually.

If preliminary preparation of raw materials is planned, you will need to buy equipment for the production of fiberboard of the following plan:

• chipping machine - from 150,000 rubles,
• steam chamber - from 200,000 rubles.

Significantly speed up the process of purchasing conveyors, industrial fans for dust blowing, lifting packing tables. In this case, the cost of technical equipment add at least another 800,000 rubles.

The full price of equipment for the production of fiberboard, automated and fully equipped, is quite impressive - from 3,000,000 rubles.

Production room

To accommodate production line does not require much space. But free space will be required for warehouses. Raw materials should be stored in a dry, well-ventilated area - to be equipped with ventilation systems. It should also be installed in workshops, since the fiberboard manufacturing technology involves the release of fine wood dust into the air.

Look for a workshop with an area of ​​at least 500 m 2 outside the city. The rent here is much lower. In addition, it will be easier to collect a package of documents for starting a business, since it will not take long to “persuade” the sanitary services that production does not interfere with residents of nearby houses.

It will be impossible to establish the process without three-phase electricity, heating and water supplied to the workshops. And if in some industries a suburban garage would be enough, then the manufacture of fiberboard needs to be carried out on a much larger and better equipped area.

Business development prospects

If you plan your activities correctly, the company has every chance of success. Start looking for clients at the stage of developing a business plan. Buyers finished products will become:

• furniture factories,
• private consumers,
• construction organizations.

Wholesale customers will bring much more profit - focus on finding just such buyers. So the products will not be stale in warehouses, and the company will work under the order.

The success of an enterprise largely depends on the range of materials offered. Immediately consider the production of soft fiberboard and hard, laminated - such material is much more expensive on the market and is more in demand. And if you save on equipment by not buying a grinder, you will lose part of the market.

When things go uphill, and the costs begin to pay off, consider launching related industries - the production of chipboard and MDF. This practice is common among entrepreneurs - the technologies are not much different, little additional equipment is required. This is a great chance to expand the range and attract more customers.

Profitability of the planned business

Capital costs and payback periods will depend on the planned capacity of the enterprise, the chosen production technology, equipment prices and the selling price of the final product.

The main items of expenditure in the organization of a mini-factory for the manufacture of fiberboard:

• purchase of equipment - from 2000000 rubles,
• purchase of raw materials for a month - from 300,000 rubles,
• rent of premises for the first 3 months - from 200,000 rubles,
• preparation of the premises for work - from 400,000 rubles.

You can save on investment by installing used equipment in the workshop.

As practice shows, the technological scheme will pay off in 4-6 years. Be patient - the process of becoming can be delayed. To be prepared for "unexpected turns", in the business plan, provide for all possible options for the development of affairs and ways to solve problems.

Set competitive prices for your products. The selling price of fiberboard depends on its type and method of processing. For example, an unprocessed slab with a size of 3.2 * 1220 * 1373 mm costs from 115 rubles per piece on the wholesale market. Polished products are more expensive.

Introduction

Carpet tide

Plate pressing

Sizing cutting of slabs

Chopping machine selection

Sorting machine selection

Selection of disintegrator

Selection of a steaming plant

Conclusion

Bibliography

wood fiber impregnation equipment

INTRODUCTION

Fibreboards are called sheet materials formed from wood fibers. They are made from wood waste or low-quality round wood. In some cases, depending on the conditions for supplying enterprises with raw materials, they are used simultaneously as wood waste, and low-grade wood in a round form. When pressed in a wet way, plates of one-sided smoothness are obtained - their surface coming out from under the press will be smooth, and traces of the mesh on which the pressing took place will remain on the reverse side.

Fig.1 Fibreboard.

Fiberboards are used in various areas of the national economy: in construction (external and internal elements, agricultural buildings); for the manufacture of built-in furniture (kitchen cabinets); in furniture production; car - and shipbuilding; production of containers, boxes, etc. In our country, the volume of production of fibreboard is increasing every year. It is a high quality, cheap finishing and structural material which favorably differs from natural wood and plywood. Fibreboards are isotropic, do not crack, have great flexibility with a high modulus of elasticity.

The plates are durable: having served for more than 20 years, they are in good condition. Ordinary oil paint, which is applied to boards used outdoors, lasts 15-18 years, i.e. longer than paint applied to natural wood.

Fibreboards are widely used in various fields of activity due to the variety of their properties.

GOST regulates the following physical and mechanical properties of fiberboards: format and thickness, bending strength, moisture, swelling, water absorption. For soft slabs, one of the main quality indicators is thermal conductivity. In addition to those listed, additional non-regulated information about the plates is important for consumers.

Thermal conductivity indicators are of paramount importance for soft slabs, since their main purpose is thermal insulation. fibreboard - good thermal insulation material.

Wood fiber boards lend themselves well to gluing. Soft boards are glued together, as well as with hard boards, wood, linoleum, metals (tin, galvanized iron, aluminum foil), cement plaster. Bonding is provided by the use of carbamide resins or polyvinyl acetate emulsions. Given the high porosity of soft boards, it is necessary to introduce a filler into adhesives and adhesive emulsions - wood or rye flour. Solid boards are glued together soft wood, linoleum and sheet metal. Hard and soft plates lend themselves perfectly to painting with oil, water-based and various synthetic enamels, pasting with paper, synthetic wallpaper and linkrust, as well as paper plastics and other sheet synthetic films.

The most common ways to make boards are wet and dry. Intermediate between them are wet-dry and semi-dry methods, which are less common.

The wet method is based on the formation of a carpet of wood fiber in an aqueous medium and hot pressing of individual sheets cut from the carpet in a wet state (at a relative humidity of about 70%).

In the process of making boards with a wet method, the wood is ground into chips; then it is turned into fibers, from which the carpet is formed. Next, the carpet is cut into sheets. Dry webs are pressed into solid boards. Wet webs are either pressed to form hard and semi-hard boards or dried to form soft (insulating) boards. The above methods can be used to produce fiber boards from any organic materials that can be fibrillated.

Fig.2 General scheme technological process of fiberboard production

Raw materials, their preparation and storage

The choice of raw materials is determined by economic feasibility, taking into account the size of its reserves, the conditions of procurement, delivery and storage. For the production of fibreboard, sawmill and woodworking waste, wood longevity, small roundwood from thinnings and logging waste.

One of the main requirements for raw materials is the possibility of obtaining the longest fiber from it. In this regard, coniferous tree species have an advantage over deciduous ones: the length of the fibers conifers(pine, spruce, fir) ranges from 2.6 to 4.4 mm, and deciduous (birch, aspen, poplar) - from 0.7 to 1.6 mm.

A characteristic of wood is its density in an absolutely dry state (Table 1).

Table 1

SpeciesWeight of 1 m3 of wood, kgabsolutely dryair-dryFreshly cutOak6507401030Beech625710968Birch370650878Larch520680833Nipple458520863Wasp willow450510762Fir414420827Spruce395450794

In the production of fiberboard wet way goes chips without crumpled edges, with a particle length of 10-35 mm (optimum 20 mm), a thickness of not more than 5 mm, with a cut angle of 30-60°C. The content of rot is allowed no more than 5%, mineral inclusions no more than 1%, bark no more than 15% (in wood chips from branches - up to 20%). With an increase in the proportion of the cortex worsen appearance boards and their strength.

Hydrophobic (petroleum paraffin, ceresin),

Strengthening (black technical albumin, pine rosin, SFZh),

Emulsifiers (oleic acid, SDB concentrate, sodium hydroxide),

Precipitators (technical sulfuric acid, aluminum sulfate),

Additives for imparting special properties to plates (oil and road bitumen, ammonium fluorosilicon).

Raw materials are delivered to the site of the enterprise in the form of roundwood, sawmill waste (slats, slabs) or wood chips. To facilitate the stacking of thin roundwood and sawmill waste, as well as for better supply to chippers, their length is 2-3 m. It is advisable to bundle such raw materials with paper ropes and stack them.

Wood longevity is stored in dense unlined stacks. Technological chips entering the enterprise site from outside can be stored in a pile, the most common handicap of which is a truncated cone.

The raw material is supplied to production in the form of conditioned wood chips, which must meet the following basic requirements: length - 25 (10-35) mm., thickness - up to 5 mm., clean cuts without wrinkled edges, clogging with bark - up to 15%, rot - up to 5%, mineral impurities - up to 1%, wood chips relative humidity - not less than 29%.

Preparation of raw materials for the production of boards, which consists in the preparation of conditioned chips, includes the following operations: cutting wood into sizes corresponding to the receiving cartridge of the chipper; cutting wood into chips; sorting chips to select the required size with regrinding of a large fraction and removal of fines; extraction of metal objects from wood chips; washing the chips to clean them from dirt and foreign matter.

Cutting logs is necessary to give the initial raw material dimensions corresponding to the parameters of the chipper, as well as to cut out areas heavily affected by rot with a wood diameter of less than 200 mm, the length of the logs entering the felling can be up to 6 m, with a larger diameter it should not exceed 3 m. The maximum allowable diameter of logs is determined by the size of the receiving cartridge of the chipper. Wood intended for the manufacture of high-quality boards and for finishing the outer layer of boards is debarked on OK-66M debarking machines.

Balancing saws, slashers (Fig. 3) and chain saws are used for bucking wood longitude.

Fig.3. Scheme of a 12-saw slash for cross-cutting round timber. 1-frame; 2-rack; 3-beam; 4-bracket; 5-disc saw; 6-mechanical separator; 7-belt conveyor for thin logs; 8-belt conveyor for thick logs.

When the diameter of the wood exceeds the allowable one, the length is cut into short pieces (1 - 1.25 m) and split on a mechanical cleaver.

To grind prepared wood into chips, multi-skin chippers are used. When chopping wood on chippers, the yield of conditioned wood chips is 85-92%; in this case, about 10% of large chips and up to 5% of sawdust are obtained.

To obtain conditioned chips, which ensure the normal operation of grinding machines, and to obtain high-quality pulp, chips are sorted at chip sorting plants. Large chips that have not passed through the sorting sieves are crushed in disintegrators. To capture metal objects, wood chips are passed through magnetic separators.

Sorted from fines and large chips, conditioned chips are fed by belt conveyors (through magnetic separators that trap metal objects) and a chip washer into bunkers, the capacity of which is designed to store at least a 24-hour supply of chips. The supply of chips from the bunkers is controlled by vibrating or auger disc unloaders.

Wood pulp production

Wood grinding is one of the critical operations in the technology of fiberboard production.

Today, the thermomechanical method of obtaining fiber from wood chips has become predominant. Since lignin, which binds individual wood fibers together, softens at temperatures above 100 ° C and melts at 172 ° C, the chips are steamed before mechanical abrasion to reduce their strength. Primary hot grinding is carried out in defibrators, secondary - in refiners or rolls (hollanders).

Fig.4 General view of the hot grinding plant: 1 - bin for wood chips; 2 - screw feeder; 3 - steaming boiler; 4 - auger for supplying heated wood chips; 5 - defibrator; 6 - main engine; 7 - return steam pipeline

The fibrous mass for ease of transportation is mixed with water to a concentration of 3%.

Since during the primary grinding of chips there are separate unground bundles of fibers and chips, the mass is subjected to additional grinding on refiners or rolls (hollenders).

The resulting mass can be coarse or fine grinding. Coarse grinding has a weak degree of fibrillation (combing). If the fibers are severely chopped and shortened, the formation of "dead grinding" is possible - a loose mass in which the fibers do not intertwine (do not felt), and when forming a carpet from them, it will tear on the mesh. Fine grinding ensures reliable felting of the fibers and the formation of a sufficiently strong carpet.

The grinding plant, schematically shown in Fig. 4, consists of a hopper with a screw feeder, through which chips are fed into a preheater with a stirrer, and from there through another screw into the actual defibrator, consisting of a fixed and movable disks. Getting through the central hole of the fixed disk onto the rotating washer, the chips are thrown into the grinding zone. The working surfaces of the disks are equipped with grooves and corrugations, in which the heated wood particles are rubbed into individual fibers and fiber bundles. Under the action of centrifugal forces and steam pressure, the resulting fibrous mass is ejected from the discs to the outside.

In order to maintain a uniform supply of chips by the auger feeder, the unloading auger of the preheater is made in a conical shape.

The compressor plug created by it prevents the return flow of steam and the pulsation of the flow of chips. With a uniform supply of chips, the defibrator works more stable and the fibers are more uniform.

At the second stage of grinding, refiners are used, and in the production of soft fiberboard, to obtain even finer grinding, gollenders or conical mills with basalt and ceramic grinding sets are used.

In the gollender (Fig. 5), the crushed mass moves in a spiral.

Fig. 5 Gollender - a and its cross section - b:

Drum; 2 - bars; 3 - a box with a basalt insert; 4 - drainer

The degree of grinding of the mass is measured on the apparatus "Defibrator-Second", characterized in degrees of grinding and has the designation DS. In numerical terms, the degree of freeness is equal to the time (in seconds) that is required to dehydrate a mixture of 128 g of absolutely dry pulp and 10 liters of water (concentration 1.28%) placed on the grid. For soft slabs, the degree of grinding should be within - 28-35 DC.

Wood fiber pulp gluing

Sizing wood fiber helps to reduce water absorption and swelling, as well as increase the mechanical strength of the boards. To give the boards water resistance, a hydrophobic substance is introduced into the wood fiber mass. Enveloping the wood fibers and filling the pores in the finished board, the hydrophobic substance prevents the penetration of moisture into it. In addition, the paraffin used as a sizing material prevents the fiber bundles from sticking to the glossy sheets of the press plates and backing (transport) nets, and also adds shine to the front surface of the plate.

Hydrophobic substances for sizing are as follows: paraffin, slack, ceresin composition, etc. Their content in the boards does not exceed 1.0% by weight, since these substances weaken the bond between the fibers, thereby reducing the strength of the boards. Water-repellent additives are introduced into the fibrous mass in the form of aqueous emulsions. To obtain a fine emulsion, high molecular weight acids (oleic, stearic, palmitic, etc.) are used as emulsifiers. To reduce the cost of finished slabs, enterprises use sulphite bardy brew concentrate as an emulsifier, distillation residues from the distillation of synthetic fatty acids and sulfate soap. A necessary condition for the deposition of hydrophobic substances on the fibers is the creation of an acidic medium in the wood fiber mass - pH 4.5-5.0. Such an environment is formed as a result of the introduction of a solution of alumina sulfate or potassium alum into the wood-fiber mass, which serve as coagulators or precipitators. Recently, it has become widely used sulfuric acid.

To increase the mechanical strength of fiberboards, adhesive additives are introduced into the mass. The introduction of albumin significantly improves the strength characteristics of the produced plates. Low-toxic water-soluble phenol-formaldehyde resin SFZh-3024B and SFZh-3014 resin are also used as adhesive additives.

Warehouses for chemicals are designed and built separately. The stock of chemicals is created based on the monthly operation of the workshop. In the fiberboard workshop itself, an expendable daily storage warehouse is located, which is located next to the room for preparing working compositions. Chemicals are delivered from the main warehouse to the consumable warehouse by an electric forklift in special containers or commercial containers.

Many enterprises receive paraffin in a railway tank, which is installed near the finished product warehouse. The paraffin is heated with live steam, after which it drains by gravity through the bottom hole and flows down a pipeline laid with a slope into a storage tank with a capacity of 60 m3. Next, the paraffin enters the supply tank, which is installed in the workshop on a pedestal. Then the paraffin is drained by gravity through a measuring tank into the tank for the preparation of a paraffin emulsion (emulsifier). The finished emulsion is pumped into a special container (tank) for storage.

The preparation of the working composition of the phenol-formaldehyde resin SFZh-3024B consists in diluting it to a working concentration of 5-10%. The dissolution of precipitants is carried out in a special tank, which is similar in design to the emulsion preparation tank.

The preparation of a sulfuric acid solution used to precipitate resin emulsions consists in diluting sulfuric acid with water to a concentration of 1.5-3%. The concentration of sulfuric acid introduced in more than 3% is undesirable, since this can cause spots on the plates during pressing and sticking to glossy sheets and transport nets.

The consumption of chemicals according to the technological instructions of VNIIdrev is determined depending on the rock composition of the raw materials, the chemical products used and the capacity of the enterprise.

Sizing compositions are introduced into the fibrous mass before it is poured into continuous sizing boxes. A prerequisite for sizing is the initial introduction of a sizing emulsion into the mass, and only after mixing the emulsion with the mass is the addition of a precipitant solution.

Carpet tide

The ebb and formation of a carpet of wood fiber occurs as a result of sequential operations: the expiration of the mass on the forming mesh, free filtration of water through the mesh, suction of water by a vacuum unit and additional mechanical wringing. When the mass flows onto the grid, free water is filtered, going into the circulating system, and suspended fibers settle on the grid. Due to the developed outer surface of the fibers obtained during grinding, conditions are created for a greater degree of their adhesion and interlacing. This connection is strengthened in the process of vacuum suction and mechanical squeezing of water from the web. The relative humidity of the canvas is adjusted to 68-72%. In this state, the sheet becomes transportable, and in addition, the maximum removal of water reduces steam consumption and reduces the time for subsequent drying of the plates. This is especially important in the production of soft boards, since they are dried not in presses, but drying chambers.

The ebb of the mass and the formation of the web is carried out on casting machines of periodic or continuous action.

The wood-fiber carpet previously dehydrated by vacuum is subjected to further mechanical dehydration - the pressure of several pairs of rolls covered with nets. The relative humidity of the carpet is about 80%. With this humidity, the carpet leaves the vacuum-forming drum and is sent to the roller conveyor for cutting and additional dehydration in a roller press. By additional dehydration, the wet web moisture content can be increased to 60%.

The formed endless wood-fiber tape-carpet is cut along the length into separate webs - blanks. Trim the side edges at the same time.

The main conditions for the formation of a wood fiber web are: uniform mass distribution over the entire width and thickness of the web, good mixing of different fiber fractions, obtaining a random orientation of the fibers, minimizing the loss of fine fibers and chemical products introduced into the mass, achieving the required moisture content of the carpet.

Careful storage and organized transport of the mass to the casting machine are necessary for even mass distribution and good mixing. Each particle of fibrous mass, being suspended in suspension, makes a movement. It occurs, firstly, under the action of gravity (the particle descends), and secondly, depending on its shape, it lends itself to rotation. Forming complex movements, fiber particles and fibers collide with each other, interlock and create conditions for flocculation. At the same time, in a rapidly moving suspension, the formation of flakes is accompanied by discontinuities and a dynamic equilibrium is established. Given this fact, it is necessary to create such conditions that the outflow of the suspension in pipelines is not disturbed by mechanical obstacles in the flow path. Corners, curvature, irregularities should be avoided internal surfaces mass pipelines.

All operations for the formation of a wood-fiber carpet should be carried out with a gradually increasing load. It has been established that the forced dehydration mode at any stage of the process causes the destruction of the fibrous structure of the carpet, a decrease in its mechanical properties in the absence of any external visible signs.

In the workshops of fibreboard, working by the wet method, an important technological and economic importance has a process for returning fiber to production. Together with the discharged water, fibers are also leaving, the content of which in the wastewater is about 1600 mg/l. The extraction of wood fibers from the discharged water allows the maximum use of raw materials and recycled water, which reduces the consumption of raw materials and fresh water per unit of manufactured boards. In addition, a decrease in the content of fibrous substances in wastewater creates favorable conditions for its subsequent processing at treatment facilities. Technological filters are used to return the fiber to production. In our country, Polish-made filters are installed at factories manufacturing wood-fiber boards.

Plate pressing

Pressing is the main operation of the technological process, which determines the quality of the boards produced and the productivity of the equipment. During pressing, the wet fibreboard is subjected to great pressure at high temperature and becomes a fibreboard. This transformation occurs due to physical, chemical and morphological changes in the moisture-saturated wood fiber.

In the process of pressing, changes occur in the cellulose part of the wood complex. The size of the elementary crystal lattice, there is an enlargement of crystalline regions. The ordering of the structure makes it possible for cellulose molecules and segments of macromolecules to approach each other at the distances necessary for the formation chemical bonds between wood fibers. At high blood pressure and high temperature, thermohydrolytic transformations of hemicelluloses are observed, which causes an increase in the content of water-soluble products in the pressed material, the oxidation of primary hydroxyl groups of sugars with the formation of carboxyl groups, the establishment of simple and ester bonds as a result of dehydration and esterification reactions. This explains that the strength and water resistance of the boards are in accordance with the quantitative changes in extractive substances, changes in functional groups, hydrogen bonds, free radicals and the mobility of the carbohydrate skeleton of wood fiber.

The strength of the plates is determined by the strength of the fibers and interfiber bonds. The tensile strength of the fibers depends on the type of wood. All the main components of the carbohydrate-lignin complex are involved in the formation of interfiber bonds, a significant part of which is in a softened, plasticized state. The presence of low molecular weight substances, a slight decrease in the degree of polymerization of cellulose, softening of lignin, and an increase in the flexibility of macromolecule chains during piezothermal treatment contribute to an increase in the contact surface between the fibers and the adhesive interaction between them.

Depending on the raw materials and methods of conducting the technological process, it is possible to obtain the required physical and mechanical properties of the plates. To select the parameters and mode of pressing, it is necessary to take into account the following initial factors: rock composition and quality of the feedstock; method and quality of mass preparation; characteristics of sizing materials and method of their introduction; technical capabilities of the press.

In the wet process, hot, hydraulic multi-storey batch presses are most widely used.

The mode of pressing depends on many factors: the quality of raw materials and mass, moisture content and thickness of wood-fiber sheets, technological parameters of the process, the state of the press and its clothes. The entire period (cycle) of pressing is divided into three technological phases: pressing, drying, hardening.

The relative humidity of the sheets before pressing is 68-72%. At low humidity (less than 65%), there is a deterioration in the quality of the boards and sometimes even delamination. The duration of the first phase of pressing is 50 - 90 s. The moisture content of fibrous cloths is adjusted to 45 - 50%. At the first stage of pressing, the density of the plate is determined.

After the first phase of pressing (squeezing), they proceed to the second phase - (drying of the plates), since further removal of water is possible only by its evaporation. To conduct the drying process, the specific pressing pressure is reduced in order to create favorable conditions for removing steam from the sheets. It is maintained at the level of 0.8 MPa. To ensure uniform release of steam from the wet fibrous web, the pressure during the drying period is kept constant.

The temperature of the press plates also has a great influence on the course of the pressing process. With the wet method of production of fibreboard, the pressing temperature is 200 - 215 °C. The increase in pressing temperature is caused by the desire to speed up the process of evaporation of water from the fiberboard.

The duration of drying is influenced by the degree of grinding of the mass and the thickness of the pressed canvases. The higher the degree of grinding of the mass and the greater the thickness of the plate, the longer the drying period. Its time, depending on the specific conditions, is 3.5 - 7 minutes. During the second pressing phase, water is removed until the relative humidity of the fibreboard is 7%. This humidity is necessary for carrying out the condensation reaction in the final stage of pressing. The practical moment of the end of the drying phase is determined by the cessation of the release of steam from the plates. In the third phase of pressing (hardening), the plates are subjected to heat treatment at elevated pressure, bringing the humidity to 0.5 - 1.5%. The duration of the third phase is selected empirically and usually does not exceed 3 minutes. The technological instruction developed by VNIIdrev recommends the following pressing modes: humidity (relative) of wood-fiber sheets entering the press 72 ± 3%; board moisture content after pressing 0.8 - 1.2%; specific pressing pressure in the extraction phase 4.2 - 5.5 MPa (with a hardwood content of more than 70% - 5.5 MPa), in the drying phase 0.65 - 0.85 MPa, in the hardening phase 4.2 - 5.5 MPa (with a hardwood content of more than 70% - 5.5 MPa). The temperature of the press plates (heat carrier at the inlet) depends on the species composition of the raw wood used.

Oil impregnation, heat treatment and dampening of fibreboards

To increase strength and moisture resistance, the plates are impregnated with oil. At the factories of fibreboard, in an isolated room, they place special lines, which include: a loading device, an input roller conveyor, an impregnation machine, an output roller conveyor and an unloading device. Plates that come out of the press are fed for impregnation, i.e. hot. For the impregnation of fibreboards, a mixture of linseed and tall oils (40 and 60%) or tall oil with the addition of lead-manganese desiccant (93.5 and 6.5%) is usually used. The oil consumption is 10 ± 2% of the weight of the boards.

Heat treatment improves the physical and mechanical properties of hard and super-hard fibreboards, improving water absorption, swelling and flexural strength. The improvement of these indicators occurs as a result of the processes of thermochemical transformations of the carbohydrate-lignin complex of the fibrous mass of the plates.

During heat treatment, under the influence of dry hot air, moisture residues are removed from the plate, and surface tension forces bring together cellulose macromolecules at distances sufficient for the formation of unoriented hydrogen bond sites between hydroxyls. In addition, heat treatment of lignin and carbohydrates leads to the formation of easily polymerizable substances with high reactivity and the creation of resinous products. Heat treatment is carried out in special heat treatment chambers of periodic or continuous action. Heat treatment is carried out at a temperature of 160 - 170°C.

Wood fiber boards are porous bodies. Dried, being in a hot state after a press or heat treatment chambers, they begin to adsorb water vapor from the surrounding air. If these slabs are packed into a dense package, their edges absorb water to a greater extent, which leads to an increase in the linear dimensions of the slabs in the peripheral zone. As a result of the occurrence of significant internal stresses, waviness is formed. To give the plates dimensional stability, it is necessary to carry out acclimatization, which consists in. moistening while cooling the plates. Humidification machines and chambers are used to moisten the plates.

Sizing cutting of slabs

Fibreboards are cut to final dimensions on sizing and cutting machines that perform longitudinal and transverse cutting. Fibreboards are cut to final dimensions on sizing and cutting machines that perform longitudinal and transverse cutting. Cutting tool- round saws. For cutting out defective areas and more convenient cutting of slabs into workpieces for carpentry and construction and other special products, in front of the format-edging machines, a saw of preliminary transverse cutting is installed.

When sizing finished boards, edge trimmings, small pieces of boards, as well as sawdust remain, which it is advisable to return to production. Shredded waste, together with sawdust, is sent by pneumatic transport to a mixing vat filled with water. Thoroughly mixed waste at a pulp concentration of 3-4% is pumped into a bulk tank in front of the secondary grinding mills. Small crushers are used to crush defective pieces of slabs. Crushed particles are fed by a pneumatic transport system into the hydropulper and through an intermediate pool for secondary grinding. The supply of waste for secondary grinding is also carried out by pneumatic transport without the use of a hydropulper.

Description of the technological scheme for the production of fibreboard

As raw materials for the production of wood fiber boards by the wet method, waste from sawmilling and woodworking, wood longevity, small roundwood from thinning and logging waste are used.

Preparation of raw materials for production consists in the preparation of conditioned wood chips. Initially, the wood is cut into sizes corresponding to the receiving cartridge of the chipper. Balance saws are used to cut logs to length.

The resulting chips after the chipper enter the sorting machine, where the technological chips are selected that meet the requirements for it. For sorting technological chips we use a sorting machine model SSh-1M.

From the sorting machine, the selected chips enter the chip storage silo. Chips with sizes exceeding the established ones are transferred for additional grinding to the DZN-1 hammer disintegrator, and then returned to the chipper. The fines screened out during the sorting process are removed from the workshop as waste.

Conditional wood chips are sent to stock bins or service bins in the grinding department. We install three bunkers of the DBO-60 brand, one of which is a reserve one.

From the feed hopper, the chips, preheated with saturated steam at a temperature of 160 ° C in the heater, are fed into the steamer through the feed hopper. We install two steaming plants "Bauer-418". The steam boiler is designed for pressure up to 1 MPa. The chips pass through the steamer under the influence of a screw conveyor. The residence time of chips in the boiler is from 1 to 10 minutes.

Chips at the same pressure are fed into the grinder by a screw conveyor. We use a defibrator brand RT-70 as a grinding apparatus. The temperature in the defibrator is maintained by supplying saturated steam. Steam simultaneously serves to remove from the reaction space of the defibrator the oxygen of the air, which destroys the wood. Steam is supplied to the apparatus through a steam valve. The steam consumption is 700 - 1500 kg/t, depending on the type of wood. Wood chips, entering the grinding chamber, are directed by the blades of a rotating disk between the disks to the grinding sectors, which grind it into fibers.

The resulting wood fiber mass under the influence of steam pressure and the blades of a rotating disk is fed into the outlet pipe to the outlet device. The wood fiber mass, having passed the outlet device, enters the diffuser, in which it gradually expands, and together with the steam it enters the cyclone at high speed, from where the fibers, which have lost a certain amount of moisture as a result of self-evaporation, are sent to the secondary grinding mill - refiner. The fiber comes out of the defibrator with a moisture content of 40 - 60%.

To improve the properties of boards, water-repellent additives are introduced into chips or wood-fiber mass. The paraffin emulsion is introduced through special nozzles of the steaming plant before the chips are ground into fibers from the paraffin supply tank. Mixing of fiber with water-soluble phenol-formaldehyde resin SFZh-3014 occurs in the mixer 10, which is installed between the drying stages.

After grinding, the fiber is fed into the cyclone of the first stage dryer 9. For the first stage of drying, we install four air fountain dryers, one of which is a backup. Air heated in a heater to a temperature of up to 160 °C serves as a drying agent. Air and fiber are moved by a centrifugal fan at a pressure of 22 MPa. After the first stage, the moisture content of the wood pulp is reduced to 40%.

Next, the fiber is sent to the dryer of the second stage. The second stage of drying is carried out in drum dryers. The fiber after the first stage of drying through a rotary shutter is fed into the drying drum, in which, moving along the drum, it is mixed with the drying agent. The drying agent is fed into the drying drum through a special channel tangentially to the cylindrical surface. The flow picks up the fiber and passes through the dryer drum in a helical line with intense heat exchange and mixing. The fiber is then discharged from the dryer through a special rotary gate. The second stage dryer uses the principle of low temperature with a large volume of drying agent. The temperature of the air entering the dryer is 180 - 200°C, and the volume of air passing through the dryer, normalized to a standard temperature of 21°C, is 52500 m3/h. After the second stage of drying, the fiber has a moisture content of not more than 8%.

Next, the fibrous mass is sent to the forming machine 12. For the formation of the carpet, two-wire vacuum-forming machines are used, in which the formation is carried out by deposition of the fibers of the mass by an air flow passing from top to bottom through a moving mesh. The carpet is laid on a moving mesh that combines three chambers and a belt and roller press. The fiber from the dosing hoppers enters the appropriate chamber, the air from which is sucked off by a fan that creates a vacuum, as well as a system for removing excess fibers from the calibrating roller. The wood fiber mass is distributed along the width of the chamber by means of an oscillating nozzle. The value of the vacuum under the grid in the chambers is 20 - 30 kPa, respectively. Depending on the density of the boards produced, the height of the layer to be laid is determined. With a density of 1 t/m3, the mass value of 1 m2 of carpet corresponds to the thickness of the fibreboard in mm.

Formed on a vacuum-forming machine, a continuous carpet is fed to a pre-pressing belt press, designed to ensure the transportability of the carpet, as well as to rationally use the hot press, reduce the gap between its plates and increase the speed of their closing. The specific pressure in the press is increased gradually. The specific prepress pressure is 0.1 - 0.15 MPa; the line pressure is 1400 N/cm. The operation of the press is synchronized with the operation of the forming machine. The speed is steplessly adjustable from 9 to 50 m/min.

Next, the continuous carpet is cut into canvases. From the belt press, the carpet moves along the belt conveyor to the cut-to-length saws designed to cut the endless carpet into sheets. There, on top of the main carpet, a fiber, formed in the form of a thin carpet, comes from the forming head of the finishing layer to apply the finishing layer to the slabs. Then, with slitting saws 16, the carpet is trimmed to a predetermined width. Oscillating Conveyor Tippel distributes the webs onto a two-tier belt conveyor system. This system consists of three sections of double-deck conveyors that feed webs into the press loader and provide a supply of webs while the hot press loader can take them.

Fiberboard sheets are fed into the press by a loader. The loading device, which ensures palletless loading of fiberboards into the press, consists of a fixed frame, a loading rack, a mechanism for raising and lowering the rack, twenty-two loader conveyors with individual drives. The limit switch stops the loader, after which it moves back, leaving the sheets in the press.

Depending on the rock composition of the raw material and the type of binder used, the pressing temperature at different plants varies between 180 - 260 °C. For soft hardwood, the pressing temperature is 180 - 220 °C, for hard wood - 230 - 260 °C. To obtain fibrous boards with a density of 1 g / cm3, it is necessary to have initial stage pressing specific pressure 6.5 - 7 MPa. The exposure time at maximum pressure is determined by the moisture content of the carpet, the pressing temperature, as well as the thermochemical processing of the raw material. Exposure at maximum pressure in order to avoid the appearance of bubbles and spots due to steam accumulating in the web should not exceed 40 s. To remove steam, it is advisable to reduce the pressure. The pressure is reduced to a value slightly lower than the steam pressure in the web, which is determined by the temperature of the heating plates of the press and the conditions of thermochemical processing of raw materials. The duration of pressing depends on the desired thickness of the finished board. The complete pressing cycle must be controlled in such a way that after the plates have passed through the press, they have a moisture content of 0.3 - 0.5%.

After pressing, the fibreboards are transferred by a system of levers of the unloading device to the unloading stack, and from there they are sent one by one to the conveyor for cutting and conditioning.

After the press, the plates have a moisture content of less than 1% and a high temperature. In the process of unloading the press, trimming the edges and filling the trolleys, the plates are cooled to 50 ° C and gain moisture up to 2%. The equilibrium humidity of the boards under normal conditions (at 20°C and 65% relative humidity) is 5 - 9%. Therefore, the plates after the pressing stage enter the conditioning stage. The loading device provides automatic loading of plates into trolleys, which are then fed into the conditioning chambers. Conditioning time 3 - 5 hours.

After the conditioning chamber, the plates are fed to the cutting and machining area by electric forklifts. Then they are placed on the receiving platform of the conveyor, and from there they are fed one by one to the longitudinal sawing machine. The feed rate is adjustable from 10 to 75 m/min. The longitudinal sawing machine has three saws, of which the two extreme ones are used for trimming the edges, and the central one, if necessary, can perform longitudinal cut: Edge saws are equipped with devices for crushing edges up to 50 mm wide. Slab size after clean cutting, mm: maximum 1830, minimum 1700.

Next, the plates are fed to a cross-cutting machine equipped with five saws, the position of which is adjustable. External saws have devices for crushing edges up to 50 mm wide. The maximum length of the plates after trimming is 5500 mm.

The slabs after cutting are stacked by a stacker and enter the slab storage, from where they are transported by a forklift.

Calculation and selection of the main and auxiliary equipment for the production of fiberboard in a wet way

Chopping machine selection

The raw material is supplied to production in the form of conditioned wood chips. Preparation of raw materials for the production of boards, which consists in the preparation of conditioned chips, includes the following operations: cutting wood into sizes corresponding to the receiving cartridge of the chipper; cutting wood into chips; sorting chips to select the required size with regrinding of a large fraction and removal of fines; extraction of metal objects from wood chips; washing the chips to clean them from dirt and foreign matter.

For the preparation of wood chips, we use the DRB-2 drum chipper.

The productivity of the device is 4 - 5 m3/h, the diameter of the drum is 1160 mm and the number of cutting knives is 4.

From the calculations of the material balance, we find that 243,661.95 kg of wet wood per day enters the chipping department, i.e. 10152.58 kg per hour. Taking the density of wood equal to 1540 m3/kg, we get:

58/1540 = 6.59 m3/h

According to the calculations, it is necessary to install two chippers.

Sorting machine selection

The resulting wood chips after chippers are sorted, as a result of which technological chips are selected that meet the requirements for it.

According to the material balance, 236565 kg of wet chips per day are supplied for sorting, which is 9857 kg per hour. Taking the weighted average conditional density of wood raw materials equal to 650 kg/m3, we determine the bulk density ?n, kg/m3, according to the equation:

H = ? k n(1)

where kp is the full-wood factor for wood chips, equal to 0.39.

?n = 650 0.39 = 253.5 kg/m3

Then we get that 9857/253.5 = 39 bulk m3 per hour goes to sorting.

For sorting technological chips, we use a sorting machine of the gyratory type, model SSh-1M, the technical characteristics of which are given in Table. 3.

Table 2. Technical characteristics of the sorting machine

IndicatorsValueProductivity, bulk m3/h60Number of sieves3Inclination of sieves, deg3 Electric motor power, kW3Weight, t1.3

Selection of disintegrator

Hammer disintegrators are used to grind large chips. We choose a disintegrator of the DZN-1 type, the technical characteristics of which are given in Table. 3.

Table 3. Technical characteristics of the DZN-1 disintegrator

IndicatorsValueProductivity, bulk m3/h18Overall dimensions, mm length2300 width1620 height825Weight, kg2248Electric motor power, kW11.4

Selection of consumable bins for conditioned wood chips

Conditional wood chips are sent to stock bins or service bins in the grinding department. There are two types of storage bins in terms of configuration: rectangular and round.

We use rectangular bunkers, placing them in the building of the woodchip preparation department. With small stocks, wood chips can be stored in vertical bins. We use a DBO-60 type bunker, the technical characteristics of which are given in Table. 4.

Table 4. Technical characteristics of the vertical bunker DBO-60

IndicatorsValues ​​Hopper capacity, m360Number of unloading screw conveyors3Productivity of one screw conveyor, m3/h3.8 - 40Installed engine power, kW21.9Height of supports, m4Total height of the bunker, m11.75Total mass of the bunker, t18.5

The required number of bunkers nb is determined by the formula:

b = Gsh t/Vb ? n kzap (2)

where Gsh is the hourly need of the designed workshop for technological chips, kg/h (according to the material balance data Gsh = 9857 kg/h); t is the time during which the hoppers ensure uninterrupted operation of the flow, h (when the chip preparation department operates in three shifts t = 3 h); Vb - volume of the bunker, m3; ?n - bulk density wood chips, kg/m3 (determined in paragraph 4.2); kzap - filling factor of the working volume of the bunker (for vertical kzap = 0.9).

b = 9857 3/60 253.5 0.9 = 2

Accordingly, we install three bunkers, one of which is a reserve one.

Selection of a steaming plant

From the feed hopper, the chips are fed by a screw feeder to a low-pressure drum feeder, from which it is sent to a preheater, where it is heated with saturated steam at a temperature of 160°C. A nozzle is mounted in the outlet section of the heater, through which paraffin is introduced into it in a molten state, sprayed with compressed air at a pressure of 0.4 MPa. From the preheater, the chips impregnated with paraffin enter directly into the hydrodynamic treatment apparatus. Fibreboard factories use continuous machines various systems.

We install the Bauer-418 steam-grinding system, which has following characteristics: horizontal steaming boiler, tubular type, diameter 763 mm, length 9.15 m, designed for pressure up to 1 MPa. The productivity of the steam plant is up to 5 t/h.

According to the calculations of the material balance, 238 tons of paraffin-impregnated wood chips per day are supplied to steaming, which is about 10 tons per hour. Accordingly, it is necessary to install two steaming plants.

CONCLUSION

The integrated use of wood is aimed at increasing the economic efficiency of the forestry and woodworking industries by reducing logging and at the same time making full use of wood waste and low-grade wood as technological raw materials. This problem continues to be relevant, despite the fact that careful attitude to natural resources and environmental protection have become a natural requirement for human activities.

It is necessary to make fuller use of timber resources, to create integrated enterprises for forest cultivation, harvesting and processing of wood. The solution to the problem of non-waste production in the forest, pulp and paper and woodworking industries is facilitated by the production of plate (sheet) materials, since they are made from various wood waste and non-commercial wood.

The use of board materials in construction increases the industrialization of production and reduces labor costs. In furniture production, their use saves labor costs and reduces the consumption of more expensive and scarce materials.

Calculations have established that 1 million m2 of fibreboard replace 16,000 m3 of high-quality lumber in the national economy, for the production of which it is necessary to procure and export 54,000 m3 of wood. The production of 1 million m2 of fibreboard saves more than 2 million rubles. by reducing the volume of logging and removal, the cost of reforestation; railway transport, as well as reducing the number of workers in logging.

LIST OF USED LITERATURE SOURCES

1. Rebrin S.P., Mersov E.D., Evdokimov V.G. Fibreboard technology, ed. Forest industry, M., 1971. 272 ​​p.

Karasev E.I. Equipment of enterprises for production wood boards. - M.: MGUL, 2002. - 320 p.

Sokolov P.V. Drying wood. Forest industry, M., 1968. 340s.

Volynsky V.N. wood board technology and composite materials. SPb.: Publishing house "Lan", 2010. - 336 p.

Stepanov B.A. Materials science for the woodworking profession. - M.: ProfObrIzdat, 2001.-328 p.

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Fiberboard production is carried out by wet and dry methods.
Wet production of fibreboard includes such operations as chipping, sizing the obtained fibrous mass, forming a carpet, pressing, impregnating the boards with oils, thermal-moisture treatment and trimming the boards.

The washed wood chips are subjected to two-stage grinding. The first grinding is carried out in defibrator mills, in which the chips are steamed and processed into large fibers. The second grinding is carried out on refiners, which make it possible to obtain thinner fibers with a thickness of 0.04 mm and a length of 1.5...2 mm. An aqueous solution of wood-fiber pulp is prepared from such fibers - pulp, which is stored in collectors or pools, stirring occasionally to maintain a certain mass concentration, preventing the fiber from settling to the bottom.

The resulting pulp is then sent to a continuous sizing box, where it is mixed with phenol-formaldehyde resin. Hydrophobic additives prepared in an emulsifier, hardening agents and precipitators are also fed there with a mixing pump at a temperature of not more than 60 ° C and such a volume at which the concentration of the resulting suspension for any ratio of the rock composition of the fibers of the raw material before casting is 0.9 ... 1, eight%. The dosage of these components depends on the type of boards, the composition of the fibers, water consumption, pressing modes, etc.

The operation of forming a wood-fiber carpet is carried out on an endless mesh in casting machines. The final humidity of the carpet for hard and superhard boards with a thickness of 3.2 mm should be (72 ± 3)%, for soft boards with a thickness of 12 mm - ((61 ... 63) ± 1)%. To form raw slabs, the pressed carpet is cut to obtain dimensions in length and width that are 30–60 mm smaller than those of the finished slab.

For hot pressing of fiberboard, multi-storey (20 floors) hydraulic presses are used. Loading and unloading of plates is carried out by whatnots. The fiberboard pressing cycle includes three phases, each of which is characterized by a certain pressure, holding time and moisture content of the boards.

The first phase is spin. Water is removed from the fibrous carpet in 30 seconds under pressure of 4.2...5.5 MPa. Humidity at the same time decreases to 45%, and the plate itself, warming up, is compacted.

The second phase is drying. The slabs are kept for 3.5...7 min at a reduced pressure (0.65...0.85 MPa), at which the humidity of the slabs reaches 8%.

The third phase is the hardening of the plates, which contributes to their compaction, increasing the strength and hydrophobic properties. The plates are kept under pressure of 0.65...0.85 MPa for 2...3 minutes.

The resulting plates must have a final moisture content of 0-.5 ... 1.5% and a flexural strength of at least 35 MPa, which is ensured by observing the technological parameters of the process: the thickness of fiberboard, the width of the press plates and the rock composition of the raw material.

In addition to hot pressing, soft fiberboards are produced by drying fibrous carpets in continuous roller dryers, in which free moisture is removed. The dryer has 8-12 rows of roller conveyors heated with saturated steam at a pressure of 0.9...1.2 MPa. The air circulation speed is 5...9 m/s, drying time is 1.5...2 hours to a moisture content of 2...3%.

To improve and stabilize the strength and hydrophobic properties of the board, they are subjected to heat treatment in intermittent chambers. The coolant in them is superheated water with a temperature of 190...210°C and a pressure of 1.8...2.2 MPa. The speed of air movement is not less than 5 m/s. The heat treatment time, taking into account the thickness of the plates, is 3...6 hours.

To give the plates dimensional stability after heat treatment, they are cooled and then moistened in humidifying machines or batch chambers. Wet slabs are cut to size and then aged for at least 24 hours.

Superhard plates are also subjected to the heat and moisture treatment procedure, but after they are impregnated with drying oils in an impregnating machine in order to increase strength and water resistance.

Production of fiberboard by dry method much the same wet fibreboard production . But the dry method can be used to produce boards of double-sided smoothness with a thickness of 5...12 mm and boards with special properties (fire- and bio-resistant, profiled, etc.).

The production of fiberboard by the dry method is also different in that when grinding chips, the operations of steaming it, separating the fibers for the outer and inner layers and mixing them with additives and resin are included.

The carpet is formed from dried fibers by felting and vacuum compaction, and then pressing with belt-roll and format presses. Hot pressing lasts 5...7 min and is carried out at a temperature of 200...230 °C with a single rise in pressure up to 6.5 MPa for 15...25 s and its stepwise discharge first to 0.8...1 .0 MPa, and then to zero. Profiled fiberboards are fixed on the press plates of special matrices.

At present, MDF, which is more homogeneous in structure, successfully competes with chipboard, which is much easier to cut and process.

All slabs, regardless of the process of their preparation, after 24 hours of exposure, are cut to size on circular saws for sizing and cutting machines according to their standard sizes.

This material is widely used in furniture production - for the manufacture of cabinets, drawers, upholstered furniture bases and other things, as well as in construction, shipbuilding and automotive. Fibreboard, or fiberboard, has excellent quality and good structural properties, and is significantly cheaper than natural wood. Flexibility, resilience, isotropy and resistance to cracking make it a widely demanded and valuable material. What is it, what does it consist of, and what technologies and equipment are used for the production of fiberboard? This article will answer these questions.

Composition of fiberboard

The main components for the manufacture of this sheet material are low quality roundwood or wood waste. Sometimes they are used simultaneously. After steaming and breaking this raw material, sheets are produced from it. In order to improve the operational properties of fiberboard, various synthetic resins (strengthening agents), as well as rosin, paraffin (water repellents), antiseptics, etc., are added to the wood pulp.

Fiberboard production technology

The manufacture of fiberboard can be carried out in two ways - wet and dry. In the first case, slabs of one-sided smoothness are obtained, in the second - two-sided. Let us consider in more detail these methods and what equipment is used for the production of fiberboard.

wet way

The most widely used wet technology. It implies that the formation of a wood-fiber carpet is carried out in an aquatic environment. The wet method of fiberboard production includes the following main steps:

1. The chips are washed and ground twice. After that, the resulting mixture is diluted with water (pulp) and stored (while it is constantly mixed).
2. The pulp is mixed with phenol-formaldehyde resin and other additives. Then it is heated to 60 degrees. This process is called mass sizing.
3. Further, the equipment for the production of fiberboard, called the casting machine, is used. It allows you to form a wood-fiber carpet from the finished mass.
4. After that, pressing, drying and hardening of the plates takes place. Together, these three procedures are called pressing. As a result, fiberboard with a moisture content of no more than 1.5% should be obtained.
5. The final stage of production is the final drying and moistening of the boards before cutting them. Finished sheets are aged to fix their shape for at least a day.

The disadvantage of this production method is that after it a large amount of Wastewater. Another significant disadvantage is the use of phenol-formaldehyde resin, since phenol is almost impossible to remove from finished fiberboard sheets.

Dry way

This production technology makes it possible to obtain fiberboard with improved performance characteristics. Many stages, with the exception of the last ones, are similar to the wet manufacturing method. The fibers are also ground twice, but the addition of water to obtain a pulp is excluded.

During the grinding process, various additives (organic and not) are introduced into the mass, which makes it possible to give the material the required properties. Next, felting is carried out to form a carpet, its compaction and pressing. At this stage, special equipment for the production of fiberboard is used - vacuum plants and tape-roll format presses.

The plates are pressed at high temperatures (up to 200 degrees) and under strong pressure, which is maintained for half a minute and then gradually decreases (from 6.5 to 1 MPa). Finishing stages - keeping and final fixing of sheets during the day. Then the finished plates are given the desired size on the format-edging circular saw machines.

With dry production fiberboard sheets are smooth on both sides and have specific operational properties - fire resistance, moisture resistance, etc.

What equipment is used for the manufacture of fiberboard?

Regardless of the production method (dry or wet method), the equipment used is similar and necessarily high-tech. In the process of manufacturing wood fiber boards are involved:

• six-saw machine for the production of fiberboard (cutting wood raw materials into blanks);
• chippers (grinding raw materials to the state of chips);
• a special high-power magnet (cleansing the mass from metal impurities);
• defibrers and refiners (for coarse and fine grinding of the mass to fibers);
• casting machines (formation of fibrous mass);
• format and tape-roll presses (giving the fibrous mixture the appearance of sheets);
• hydraulic press (carpet compaction);
• grinding machines (thickness leveling and smoothing of fiberboard sheets).

To obtain high-quality fibreboard, it is important not only to use modern high-tech equipment, but also to set it up correctly in order to produce material with a minimum amount of rejects.

The manufacture of fiberboard is a rather laborious process, but this business is in high demand today. This material is in good demand among consumers, as it has favorable advantages (quality, wear resistance and price) over more expensive and less functional ones.