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Laminated Veneer Lumber (LVL) for short, is a multi-layer whole veneer that is glued together according to the grain as the main group. Greatly reduces the impact on strength.
Uses: Special products for sliding wood, fumigation-free wooden boxes, and fumigation-free pallets for large packages and heavy-duty boxes. It can produce indoor door and window frames, floor keels and other products.
LVL profiles are special products for container skids and large equipment containers. Because of their high strength, good straightness, and can be customized in different sizes, they are widely used in packaging, furniture, and construction.
The utilization rate of raw materials is as high as 100%;
1.LVL has strong seismic performance and shock absorption performance and can resist periodic fatigue damage.
2. The processing of LVL is the same as that of wood, which can be sawed, sliced, chiseled, tenoned, nailed, etc.;
The building formwork is a temporary support structure, which is manufactured according to the design requirements, so that the concrete structure and components are formed according to the specified position and geometric size, maintain their correct position, and bear the self-weight of the building formwork and the external load acting on it. The purpose of formwork engineering is to ensure the quality of concrete engineering and construction safety, speed up the construction progress and reduce engineering costs. Therefore, this requires the stability and compression resistance of the building formwork to be strong. Moreover, the building formwork is easy to load and disassemble, and can also be recycled many times.
Building formwork is a common material in construction and is a building structure that meets the needs of temporary support. There are many types of building formwork, such as: wooden building formwork, clear water building formwork, steel building formwork, aluminum alloy building formwork, etc. These four are relatively common building formwork.
(1) Wooden building formwork: Wooden building formwork is a common type of building formwork. It is lighter in size, more convenient for transportation and turnover, more convenient for building structures, and has strong plasticity.
(2) Clear water building formwork: Clear water building formwork does not need to use a release agent, and the concrete after use is as smooth as "clear water", and does not require secondary plastering, which can shorten the construction period. Qingshui building formwork also has the advantages of water resistance, no swelling, no deformation in summer, no warping and no brittleness in winter, and it can be thrown and sawed freely.
(3) Steel building formwork: The building formwork of this material is convenient for construction, has strong versatility, can be recycled for many turnovers, and has strong material firmness and stability.
(4) Aluminum alloy building formwork: Aluminum alloy building formwork is easy to assemble, has good stability and strong pressure bearing. Aluminum alloy building formwork can be freely combined according to different shape requirements, and the combination is simple, and the number of repeated recycling is high.
Eco-boards are also called paint-free boards and melamine boards, and are generally composed of surface paper, decorative paper, covering paper and bottom paper.
In a broad sense, the ecological board is equivalent to the melamine veneer. Its full name is melamine impregnated film paper veneer wood-based panel. It is paved on the surface of particleboard, moisture-proof board, medium density fiberboard, plywood, blockboard or other hard fiberboard, and is a decorative board formed by hot pressing.
The ecological board in the narrow sense only refers to the melamine veneer with the substrate used in the middle as spliced solid wood (such as Malacca, fir, paulownia, poplar, etc.). Mainly used in furniture, cabinets, bathroom cabinets and other fields.
The surface paper is placed on the top layer of the decorative board to protect the decorative paper, so that the surface of the board after heating and pressing is highly transparent, hard and wear-resistant. This kind of paper requires good water absorption, white and clean, and transparent after dipping.
Decorative paper, that is, wood grain paper, is an important part of the decorative board. It has a background color or no background color. The decorative paper printed into various patterns is placed under the surface paper and mainly plays a decorative role. This layer requires paper Has good hiding power, impregnation and printing properties.
Covering paper, also called titanium white paper, is generally placed under the decorative paper when making light-colored decorative boards to prevent the underlying phenolic resin from penetrating the surface. Its main function is to cover the color spots on the surface of the substrate. Therefore, good coverage is required. The above three kinds of paper are impregnated with melamine resin respectively.
The bottom paper is the base material of the decorative board, which plays a role in the mechanical properties of the board. It is made by soaking in phenolic resin glue and drying. During production, the number of layers can be determined according to the application or the thickness of the decorative board.
Among the container boards, the container bottom board is a kind of planning board that requires serious technology. The wood that needs to be selected is very strict in terms of air-dry density, bending strength and other aspects. The bottom plate of the container is mainly plywood, and its main manufacturing method is to cut the log into the veneer to the required size, apply appropriate glue, cold press and hot press to set the shape. Added new sources for crafting container floors as raw materials. Plywood can not only replace the traditionally made container floor, but also reduce the cost of the container floor, which is of great significance in reducing the felling of tropical loose-leaf wood, increasing the demand for containers, and making the output value of the container floor become larger and larger.
The main material of the bottom plate of the container is wood, which plays a role in supporting the goods in the box and protecting the goods to a certain extent.
The structure itself is not complicated, but it has relatively strict technical requirements.
The production methods of plywood manufacturers are generally divided into three types: wet heat method, dry cooling method and dry heat method.
Dry-heat production: The rotary-cut veneer is dried so that the moisture content of the veneer is in the range of 8%-12%, and then the veneer is glued and pressed into a board in a hot press. The production characteristics of this method are: due to high temperature gluing, the production time is short, the output is large, the gluing strength is high, and the product quality is good. The board surface is smooth and flat, not easy to deform. Suitable for all types of adhesive production. This method overcomes the shortcomings of the moist heat method and the dry cooling method. The production is more flexible, and large, medium and small enterprises can use it in production, and the products produced are more suitable for the needs of the market. Therefore, plywood produced by domestic and foreign enterprises is usually produced by dry heat method.
The disadvantage of dry-cooling production is that the production cycle of plywood is long due to the long pressing time. It is more suitable for the production of small enterprises.
Dry and wet refers to whether the veneer used for glue pressing is dry veneer or wet veneer. Cold and hot refers to the use of hot-pressed or cold-pressed gluing.
The disadvantage of using the wet heat method for production is that due to the relatively high moisture content of the veneer, the hot pressing time is long, the productivity is low, and the plywood needs to be dried after hot pressing. Because it is a plywood produced by the moist heat method, the internal stress is relatively large, it is easy to warp and deform, and the bonding strength is low.
Wood based panel is a board or molded product that is made of wood or other non-wood plants as raw materials, separated into various unit materials by certain mechanical processing, and glued with or without adhesives and other additives. It mainly includes three types of products, including plywood, particle board and fiberboard. There are hundreds of extended products and deep-processing products.
Paint-free board, Ou Song board, MDF, particle board, fiberboard, man-made board, the product has unique advantages such as water and cold resistance, high and low temperature resistance, etc. , MDF, particle board, Ou Song board, solid wood jigsaw self-adhesive, anti-fold special board cross-bonding, and wood and aluminum, stainless steel bonding. Paint-free board, Ou Song board, MDF, particle board, fiberboard, wood-based panel adhesives have high bonding strength, cold resistance and water resistance, and are high-grade environmentally friendly adhesives.
Whether the plywood is heat treated or steam treated (temperature 180℃), after 5 cycles of treatment, the deformation recovery rate decreases with the prolongation of treatment time. For example, the deformation recovery rate of the untreated specimen after 5 cycles was more than 80%, the deformation recovery rate of the heat treatment for 10h and 20h decreased to 25% and 20%, respectively, while the deformation recovery rate of the water vapor treatment for 8min and 5 cycles was reduced. In contrast, the effect and efficiency of the steam treatment method are better than that of the heat treatment.
Cushion pads are often required during hot presses for laminate flooring, particleboard, melamine veneered panels, wooden doors, and furniture. In the working combination of the hot press, the buffer pad is sandwiched between the hot pressing plate and the template. Its main function is to make the working pressure and working temperature of the hot pressing plate evenly transmitted, and to make the bonding between the paper veneer and the substrate It is more dense, uniform and smooth, thus improving the surface and internal quality of the veneer. The buffer pad also has excellent properties such as heat resistance, compensation for platen errors, and template protection.
Hot press cushions are often used in heat presses to press laminate floors, particle boards, veneers, wooden doors, furniture and other occasions. In the working combination of the hot press, the silicone cushion of the hot press is installed between the hot pressing plate and the template, so that the working pressure and temperature of the hot pressing plate can be evenly transmitted, so that the veneer and the substrate are more tightly, evenly and evenly bonded And together, so as to improve the surface and internal quality of the product, and can make up for the error of the pressing plate, and protect the template from damage.
Hot press cushion is a product with good toughness. The product of silica gel has compact structure, strong impact resistance, good elasticity, high tensile tear strength, no deformation, uniform thickness, good cushioning performance, uniform heat conduction, and heat conduction. Fast, pressure, wear, upper limit of use and other characteristics
Why is purple copper better than brass?
Purple is better, phosphor copper (copper scale strict copper) has poor toughness
Purple is pure copper, because pure copper is purple, and the toughness of pure copper is stronger than phosphor copper
Copper alloys are divided into brass, copper-nickel alloy, bronze
Cupronickel: mainly adding nickel alloying elements
Bronze: In the past, it refers to copper-tin alloy, and later, in addition to yellow and white copper, copper-nickel alloy is bronze
Phosphor bronze is a type of bronze also known as phosphor bronze, tin bronze, tin phosphor bronze
Phosphor bronze has good flexibility and high hardness
In order to prolong the service life of the second-hand heat press machine, we must maintain the heat press plate. For example, wood beams and other sundries are often caught between the hot-pressed plate and the lining board, and the lining board needs to be disassembled regularly for cleaning.
1. Remove the hot press plate from the hot press machine, brush off the rust with a steel brush, and then use dilute hydrochloric acid (15% to 20% concentration) to remove the rust spots, so that the metal color of the press plate is exposed.
2. Use φ5mm 422 electrode for surfacing welding on the corrosion zone. Because single-sided surfacing will cause the pressure plate to bend, it is advisable to use double-sided surfacing to make the welding surfacing stress offset each other.
3. Plane both sides of the surfacing welded pressure plate, and the planing amount is 0.5mm.
4. If the welding seam of the plug is cracked due to planing, it needs to be repaired. That is, after double-sided planing, each platen is subjected to steam pressure test one by one, and if water drops are found, mark them.
5. After turning off the test steam, use an angle grinder to grind out a long groove or a round groove at the weld where the water polo emerges, then build up welding, and then use a grinder to grind it flat.
6. When installing the upper liner, be sure to pad the wooden beams before pressing it up. Slabs that are damaged or of different sizes cannot enter the hot press. It is not allowed to directly press the fiberboard without the liner.
7. It is necessary to remove the steam condensate in the hot plate of the hot press in time to avoid internal corrosion. If part (or all) of the hot platen is not hot, it means that the internal channel is blocked and needs to be removed in time.
The upper and lower liners of the hot-pressed plate are the key points, because they are used to protect the surface of the hot-pressed plate, especially the upper liner, which will affect the surface quality of the slab. Therefore, the upper liner should be replaced once a week to ensure the quality of the finished product.
If the plywood heat press machine is shut down for a long time, the steam condensate in the heat press plate should be drained to prevent it from corroding the heat press plate.
Cold press machine, that is, cold dryer compressor. The amount of water vapor in the compressed air is determined by the temperature of the compressed air: while keeping the compressed air pressure basically constant, reducing the temperature of the compressed air reduces the water vapor content in the compressed air, and the excess water vapor condenses into liquid. The refrigerated dryer (refrigerated dryer) uses this principle to dry compressed air with refrigeration technology.
The cold press is used to slowly straighten and level the uneven plate with slow force! The hot press uses strong and heat to instantly cure and strengthen the board and glue!
The maximum pressure is 0.8MPA, and it is enough to choose a lot of large cubes according to the air supply flow required. The cold presses used by sheet metal companies are basically used to correct the sheets. The presses are not very large, but the pressing time is basically between 20 minutes and 60 minutes. , and some even longer! This process is mainly to provide good conditions for the subsequent work of the hot press!
Application field: used for furniture production, processing and production of wooden plywood pressing parts such as speakers, wood industry, decoration, plastic, flat plywood, plywood, particleboard, veneer and so on. With high production efficiency and good quality, it is suitable for the production of wood products in various furniture production units and other industries.
Pre-pressing is a new process commonly used in the modern plywood industry. And in order to meet the requirements of the pre-pressing process, the adhesive should have initial viscosity. At present, a certain amount of fillers (such as soybean flour, wheat flour, etc.) that can play a tackifying role are added to the adhesive, or a certain amount of polymer is added to the urea-formaldehyde resin. methods such as vinyl alcohol. The pressing process includes slab pre-pressing and hot-pressing gluing, which is a key process in the manufacture of plywood. Before the slab enters the hot press for hot pressing and gluing, it is pressed in the cold press for a short time to make the veneer basically bond as a whole.
The veneer hot press used in the furniture industry is basically suitable for the size of wood-based panels (1220x2440mm). The board surface pressure is usually 0.2~0.4MPa and the corresponding total pressure is 120T. In addition to the main technical parameters such as pressure, number of layers, and surface pressure, there are other technical parameters such as opening, closing time, heating temperature and productivity, which should be determined according to different process requirements. The working process of the hot press for veneering can be divided into five processes: closing, boosting, maintaining pressure, depressurizing, and descending. The host of the press can be divided into three parts from the realization of functions: heating system (providing heat source), hydraulic system (providing pressure and controlling the action of the press) and the press body (frame, control part).
1. Heating system of plywood hot press machine
(1) Comparison of heating methods
The heating method affects the temperature selection, process control, and quality of processed products when the hot press is used.
The traditional heating methods are steam heating and electric heating. Steam heats up quickly, but it needs to be equipped with a pressure boiler. The pipeline pressure is high, and the steam is easy to condense into water, causing uneven temperature on the plate surface; electric heating has the characteristics of fast temperature rise, high heating temperature, and easy control, but it consumes a lot of power The cost is high, and there are disadvantages such as the failure of the resistance wire during specific use, which is not easy to replace.
The advantages of heat conduction oil heating are: high heat capacity, uniform temperature, it can be heated to a very high temperature under normal pressure, and the heat loss is small
It can reduce the production cost, but its disadvantage is that the heating speed is slow and it is not easy to control the temperature. In the furniture industry, the general hot pressing temperature should be
When the demand is not high, the hot water circulation boiler can also achieve satisfactory results, and the fixed investment and operating costs are very low.
(2) Performance of hot pressing plate
The performance of the hot press plate can be evaluated from several aspects. First, the use of the press plate material, then the processing accuracy, and finally the arrangement of the medium channels in the hot press plate.
The hot-pressed plate is generally made of a whole piece of pressed steel plate through deep hole drilling, and is mainly heated by dry oil and steam: the other isThe form of aluminum plate attached to the surface after welding the pipeline is mainly used for electric heating. Using the whole steel plate can avoid oil leakage caused by poor sealing, and has high rigidity and strength, but the hot-pressed plate is thicker; the latter is usually in the form of a thin plate, and due to stress generated during welding and processing, high processing accuracy is required.
The hot-pressed plate is thin and easy to preheat and control the temperature, but it has high requirements for the processed parts. The uneven thickness of the workpiece will cause the deformation of the platen and affect the quality of subsequent processing; the thicker hot-pressed plate is beneficial to increase the heat capacity and improve the strength and rigidity. But it will increase the size of the press and consume more steel.
During manufacturing and processing, it should be ensured that the flatness of the hot pressing plate and the upper and lower surfaces have sufficient parallelism. The flatness tolerance of the hot pressing plate should be within the range of 0.1-0.18mm, and the parallelism tolerance should be within the range of 0.15-027mm. The surface of the pressing plate The roughness is 3.2um. The temperature difference should not exceed 2-3°C in the entire width of the hot pressing plate. If the temperature difference is too large, the moisture content will be uneven, the product will warp easily, and the strength and appearance quality of the product will be affected.
The heating channel through which the heat medium flows in the heat press plate is generally not paid attention to by people in the furniture industry. The correct circuit design should be based on the principle of facilitating the flow of heat medium, facilitating the uniform temperature rise of the plate surface, and reducing the leakage of heat medium. For the small press hot plate used in the furniture industry, the design of single channel and double circuit is generally adopted, which can meet the requirements of use.
(3) Connection and sealing
The use of suitable connection methods and sealing elements is of great significance for heat transfer under high temperature and high pressure. At present, the connecting pipeline of the hot plate is basically made of hose, which makes the connection very convenient. In China, mainly metal hoses are used, and some manufacturers use imported Teflon hoses. Both methods can be used. The fatigue resistance of Teflon hose is better than that of metal hose. Asbestos rubber sheet is traditionally used as the gasket material, and new materials such as polytetrafluoroethylene and wound graphite have better sealing effects.
2. Control system of plywood hot press machine
The control system of the hot press mainly controls the work of the heating system and the hydraulic system, and its sensitivity and accuracy directly affect the accuracy of the press. Due to the complex composition of the control part, it is usually a problem-prone part. For presses with complex functions, such as vacuum lamination and veneer presses, many domestic press manufacturers directly import foreign control systems, and at the same time reduce the use of low-reliability control components such as solenoid valves as much as possible in the press.
3. Hydraulic system of plywood hot press machine
(1) Technological requirements of the hydraulic system
The hydraulic system of the hot press has two basic work requirements: applying pressure to the workpiece and driving the hot pressing plate to achieve specific movements. The stability of fast closing and pressure holding is an important index to evaluate the performance of hydraulic system.
The heating and curing of the glue should be completed in the pressure holding stage when dry veneering, so the fast closing speed is beneficial to the process and efficiency. On the one hand, it can reduce the heating of the slab under non-pressure and prevent the surface of the slab from losing too much water. , cause warping, and also prevent the pre-curing of the glue and reduce the quality of the veneer: on the other hand, it can shorten the auxiliary time and improve the productivity of the press. In order to make the opening and closing of the press stable, a mechanical synchronization device is generally provided or a hydraulic system is used to maintain synchronization.
(2) hydraulic cylinder
The hydraulic cylinder is the core part of the hydraulic system. At present, most wood processing presses use plunger hydraulic cylinders. Large-diameter cylinder plungers are mostly made of alloy casting, which is characterized by high hardness, thick hardness layer, scratch resistance, and excellent performance. Dry carbon steel heat treatment column
Plug: small-diameter cylinder plunger, mainly made of carbon steel heat-treated surface with hard chrome plating, and the surface hardness layer is thin.
Since the hot press usually requires a fast opening and closing speed and withstands impact pressure, the cylinder body must be made of higher strength materials. For ordinary hydraulic cylinders with small diameter and long strokes, seamless thick-walled steel pipes can be used to manufacture them. Casting or forging cylinders can be used for some demanding cylinders.
Usually, the working surface of the hot press used in wood processing and furniture manufacturing is relatively large. In order to make the pressure distribution uniform and consider the rationality of the structural layout, most of them adopt a multi-cylinder structure.
There are not many problems in the production of the heat press itself, but a large part of them is caused by the hydraulic system, such as oil leakage and failure to maintain pressure. A lot of knowledge and requirements about the hydraulic system cannot be fully stated here, but it must be paid attention to when selecting.
1. Precision platen working table,it can make the pressure distribution of the whole table evenly and the flatness of the pressure maintaining surface for a long time.
2. Easy and convenient control panel easy for operation.
3. Timing control,Set the appropriate time, when the set time is reached, the pressure plate will automatically release and beep to remind the operator.
4. Thick steel sheet and tough machine body stable and durable.
1. Our machine's Steel plate are based on the pressure's requires to custom, to achieve our commitment pressure, quality assurance.
2. The use of hydraulic system work, lifting speed, pressure uniformity, high efficiency.
3. Our machine's most of electrical components selection of Schneider or Chinese famous brand, main parts have option has CE authentication products.
4.Fast and efficient pressing, emergency safety braking, trip limited device.
5.Automatic compression and unloading pressure function.
6.Workbench height convenient worker operation
7.With overpressure automatic control circuit and pressure off the oil protection, automatic lift, automatic oil off.
8.The upper and lower pliers by the gantry milling finishing, to ensure absolute formation.
Cold press machine belongs to the pressing machine.Plywood Cold press machine is mainly used to press the gluing veneer, so make gluing veneer shaping, and then put into the hot press machine to press.
It is important to improve the quality of plywood, and it is an important step.Plywood Cold press machine in general consists with the frame, fixed beam, moving beam, the plate device, cylinder and hydraulic system, electric control system components.
Plywood Cold press machine is also called pre-press machine, which is the auxiliary machine in plywood production line, which is used to shorten the cycle time of hot press and improve the quality of plywood before gluing plywood.
A cold pressmachine is a heavy duty machine that will make your production line more efficient and profitable.
This is a machine you can expect to have for a very long time and should be seen as an investment instead of a cost.
It is well known that cold gluing is the best solution for certain types of applications.
The cold process can produce a finished product with better characteristics than those which can be obtained by hot pressing.
One of the limitations of a cold press is the long curing times of the glue.
This takes much longer than the hot press.However, this limitation is being overcome by the new generation of glues.
Glue curing time has been greatly reduced when used within a cold press.
Cold presses use ambient platens, or rollers to generate force. The amount of temperature, pressure, time and moisture content all factor into how the process works.
Cold presses can also be more economical to run then hot presses. Which is a bonus when energy prices are at their highest.
Hydraulic Cold presses create greater forces to produce products that may need shaping. Used for making doors, room dividers and much more.
These machines can be used to work with plywood, MDF sheets and various other surfaces.
Cold presses allow you to press in a stack using cold curing adhesives. They are used for veneering chip board and MDF panels, laminate panels, doors and more.
Cold presses are popular in the furniture industry.
Whereas hot presses are popular in, but not limited to, the marine industry for making polymer fenders.
Hot pressing on the other hand have become very mature in terms of technology after years of development. The operation of the machine is also very simple. The temperature, pressure and time can be set, and the degree of automation is superb.
When it comes to heat pressing of plywood, you typically have a choice between hot pressing and cold pressing. Both are used for flattening, bonding, veneering and pressing of wood sheets. Choose one that fits your requirement of intended application.
Cold pressing normally takes a longer time, which is about 3-4 hours or so. For applications, cold plywood pressing machines are mostly used in the production of wooden cabinets and doors. As the name implies, the cold press plywood press machine is only pressed at room temperature, and the hot press can heat the sheet, the temperature can be up to 300 degrees, and the flatness of the hot press is higher.
Laminated Veneer Lumber (LVL) for short, is a multi-layer whole veneer that is glued together according to the grain as the main group. Greatly reduces the impact on strength.
Uses: Special products for sliding wood, fumigation-free wooden boxes, and fumigation-free pallets for large packages and heavy-duty boxes. It can produce indoor door and window frames, floor keels and other products.
LVL profiles are special products for container skids and large equipment containers. Because of their high strength, good straightness, and can be customized in different sizes, they are widely used in packaging, furniture, and construction.
The utilization rate of raw materials is as high as 100%;
1.LVL has strong seismic performance and shock absorption performance and can resist periodic fatigue damage.
2. The processing of LVL is the same as that of wood, which can be sawed, sliced, chiseled, tenoned, nailed, etc.;
The building formwork is a temporary support structure, which is manufactured according to the design requirements, so that the concrete structure and components are formed according to the specified position and geometric size, maintain their correct position, and bear the self-weight of the building formwork and the external load acting on it. The purpose of formwork engineering is to ensure the quality of concrete engineering and construction safety, speed up the construction progress and reduce engineering costs. Therefore, this requires the stability and compression resistance of the building formwork to be strong. Moreover, the building formwork is easy to load and disassemble, and can also be recycled many times.
Building formwork is a common material in construction and is a building structure that meets the needs of temporary support. There are many types of building formwork, such as: wooden building formwork, clear water building formwork, steel building formwork, aluminum alloy building formwork, etc. These four are relatively common building formwork.
(1) Wooden building formwork: Wooden building formwork is a common type of building formwork. It is lighter in size, more convenient for transportation and turnover, more convenient for building structures, and has strong plasticity.
(2) Clear water building formwork: Clear water building formwork does not need to use a release agent, and the concrete after use is as smooth as "clear water", and does not require secondary plastering, which can shorten the construction period. Qingshui building formwork also has the advantages of water resistance, no swelling, no deformation in summer, no warping and no brittleness in winter, and it can be thrown and sawed freely.
(3) Steel building formwork: The building formwork of this material is convenient for construction, has strong versatility, can be recycled for many turnovers, and has strong material firmness and stability.
(4) Aluminum alloy building formwork: Aluminum alloy building formwork is easy to assemble, has good stability and strong pressure bearing. Aluminum alloy building formwork can be freely combined according to different shape requirements, and the combination is simple, and the number of repeated recycling is high.
Eco-boards are also called paint-free boards and melamine boards, and are generally composed of surface paper, decorative paper, covering paper and bottom paper.
In a broad sense, the ecological board is equivalent to the melamine veneer. Its full name is melamine impregnated film paper veneer wood-based panel. It is paved on the surface of particleboard, moisture-proof board, medium density fiberboard, plywood, blockboard or other hard fiberboard, and is a decorative board formed by hot pressing.
The ecological board in the narrow sense only refers to the melamine veneer with the substrate used in the middle as spliced solid wood (such as Malacca, fir, paulownia, poplar, etc.). Mainly used in furniture, cabinets, bathroom cabinets and other fields.
The surface paper is placed on the top layer of the decorative board to protect the decorative paper, so that the surface of the board after heating and pressing is highly transparent, hard and wear-resistant. This kind of paper requires good water absorption, white and clean, and transparent after dipping.
Decorative paper, that is, wood grain paper, is an important part of the decorative board. It has a background color or no background color. The decorative paper printed into various patterns is placed under the surface paper and mainly plays a decorative role. This layer requires paper Has good hiding power, impregnation and printing properties.
Covering paper, also called titanium white paper, is generally placed under the decorative paper when making light-colored decorative boards to prevent the underlying phenolic resin from penetrating the surface. Its main function is to cover the color spots on the surface of the substrate. Therefore, good coverage is required. The above three kinds of paper are impregnated with melamine resin respectively.
The bottom paper is the base material of the decorative board, which plays a role in the mechanical properties of the board. It is made by soaking in phenolic resin glue and drying. During production, the number of layers can be determined according to the application or the thickness of the decorative board.
Among the container boards, the container bottom board is a kind of planning board that requires serious technology. The wood that needs to be selected is very strict in terms of air-dry density, bending strength and other aspects. The bottom plate of the container is mainly plywood, and its main manufacturing method is to cut the log into the veneer to the required size, apply appropriate glue, cold press and hot press to set the shape. Added new sources for crafting container floors as raw materials. Plywood can not only replace the traditionally made container floor, but also reduce the cost of the container floor, which is of great significance in reducing the felling of tropical loose-leaf wood, increasing the demand for containers, and making the output value of the container floor become larger and larger.
The main material of the bottom plate of the container is wood, which plays a role in supporting the goods in the box and protecting the goods to a certain extent.
The structure itself is not complicated, but it has relatively strict technical requirements.
The production methods of plywood manufacturers are generally divided into three types: wet heat method, dry cooling method and dry heat method.
Dry-heat production: The rotary-cut veneer is dried so that the moisture content of the veneer is in the range of 8%-12%, and then the veneer is glued and pressed into a board in a hot press. The production characteristics of this method are: due to high temperature gluing, the production time is short, the output is large, the gluing strength is high, and the product quality is good. The board surface is smooth and flat, not easy to deform. Suitable for all types of adhesive production. This method overcomes the shortcomings of the moist heat method and the dry cooling method. The production is more flexible, and large, medium and small enterprises can use it in production, and the products produced are more suitable for the needs of the market. Therefore, plywood produced by domestic and foreign enterprises is usually produced by dry heat method.
The disadvantage of dry-cooling production is that the production cycle of plywood is long due to the long pressing time. It is more suitable for the production of small enterprises.
Dry and wet refers to whether the veneer used for glue pressing is dry veneer or wet veneer. Cold and hot refers to the use of hot-pressed or cold-pressed gluing.
The disadvantage of using the wet heat method for production is that due to the relatively high moisture content of the veneer, the hot pressing time is long, the productivity is low, and the plywood needs to be dried after hot pressing. Because it is a plywood produced by the moist heat method, the internal stress is relatively large, it is easy to warp and deform, and the bonding strength is low.
Wood based panel is a board or molded product that is made of wood or other non-wood plants as raw materials, separated into various unit materials by certain mechanical processing, and glued with or without adhesives and other additives. It mainly includes three types of products, including plywood, particle board and fiberboard. There are hundreds of extended products and deep-processing products.
Paint-free board, Ou Song board, MDF, particle board, fiberboard, man-made board, the product has unique advantages such as water and cold resistance, high and low temperature resistance, etc. , MDF, particle board, Ou Song board, solid wood jigsaw self-adhesive, anti-fold special board cross-bonding, and wood and aluminum, stainless steel bonding. Paint-free board, Ou Song board, MDF, particle board, fiberboard, wood-based panel adhesives have high bonding strength, cold resistance and water resistance, and are high-grade environmentally friendly adhesives.
Whether the plywood is heat treated or steam treated (temperature 180℃), after 5 cycles of treatment, the deformation recovery rate decreases with the prolongation of treatment time. For example, the deformation recovery rate of the untreated specimen after 5 cycles was more than 80%, the deformation recovery rate of the heat treatment for 10h and 20h decreased to 25% and 20%, respectively, while the deformation recovery rate of the water vapor treatment for 8min and 5 cycles was reduced. In contrast, the effect and efficiency of the steam treatment method are better than that of the heat treatment.
Cushion pads are often required during hot presses for laminate flooring, particleboard, melamine veneered panels, wooden doors, and furniture. In the working combination of the hot press, the buffer pad is sandwiched between the hot pressing plate and the template. Its main function is to make the working pressure and working temperature of the hot pressing plate evenly transmitted, and to make the bonding between the paper veneer and the substrate It is more dense, uniform and smooth, thus improving the surface and internal quality of the veneer. The buffer pad also has excellent properties such as heat resistance, compensation for platen errors, and template protection.
Hot press cushions are often used in heat presses to press laminate floors, particle boards, veneers, wooden doors, furniture and other occasions. In the working combination of the hot press, the silicone cushion of the hot press is installed between the hot pressing plate and the template, so that the working pressure and temperature of the hot pressing plate can be evenly transmitted, so that the veneer and the substrate are more tightly, evenly and evenly bonded And together, so as to improve the surface and internal quality of the product, and can make up for the error of the pressing plate, and protect the template from damage.
Hot press cushion is a product with good toughness. The product of silica gel has compact structure, strong impact resistance, good elasticity, high tensile tear strength, no deformation, uniform thickness, good cushioning performance, uniform heat conduction, and heat conduction. Fast, pressure, wear, upper limit of use and other characteristics
Why is purple copper better than brass?
Purple is better, phosphor copper (copper scale strict copper) has poor toughness
Purple is pure copper, because pure copper is purple, and the toughness of pure copper is stronger than phosphor copper
Copper alloys are divided into brass, copper-nickel alloy, bronze
Cupronickel: mainly adding nickel alloying elements
Bronze: In the past, it refers to copper-tin alloy, and later, in addition to yellow and white copper, copper-nickel alloy is bronze
Phosphor bronze is a type of bronze also known as phosphor bronze, tin bronze, tin phosphor bronze
Phosphor bronze has good flexibility and high hardness
In order to prolong the service life of the second-hand heat press machine, we must maintain the heat press plate. For example, wood beams and other sundries are often caught between the hot-pressed plate and the lining board, and the lining board needs to be disassembled regularly for cleaning.
1. Remove the hot press plate from the hot press machine, brush off the rust with a steel brush, and then use dilute hydrochloric acid (15% to 20% concentration) to remove the rust spots, so that the metal color of the press plate is exposed.
2. Use φ5mm 422 electrode for surfacing welding on the corrosion zone. Because single-sided surfacing will cause the pressure plate to bend, it is advisable to use double-sided surfacing to make the welding surfacing stress offset each other.
3. Plane both sides of the surfacing welded pressure plate, and the planing amount is 0.5mm.
4. If the welding seam of the plug is cracked due to planing, it needs to be repaired. That is, after double-sided planing, each platen is subjected to steam pressure test one by one, and if water drops are found, mark them.
5. After turning off the test steam, use an angle grinder to grind out a long groove or a round groove at the weld where the water polo emerges, then build up welding, and then use a grinder to grind it flat.
6. When installing the upper liner, be sure to pad the wooden beams before pressing it up. Slabs that are damaged or of different sizes cannot enter the hot press. It is not allowed to directly press the fiberboard without the liner.
7. It is necessary to remove the steam condensate in the hot plate of the hot press in time to avoid internal corrosion. If part (or all) of the hot platen is not hot, it means that the internal channel is blocked and needs to be removed in time.
The upper and lower liners of the hot-pressed plate are the key points, because they are used to protect the surface of the hot-pressed plate, especially the upper liner, which will affect the surface quality of the slab. Therefore, the upper liner should be replaced once a week to ensure the quality of the finished product.
If the plywood heat press machine is shut down for a long time, the steam condensate in the heat press plate should be drained to prevent it from corroding the heat press plate.
Cold press machine, that is, cold dryer compressor. The amount of water vapor in the compressed air is determined by the temperature of the compressed air: while keeping the compressed air pressure basically constant, reducing the temperature of the compressed air reduces the water vapor content in the compressed air, and the excess water vapor condenses into liquid. The refrigerated dryer (refrigerated dryer) uses this principle to dry compressed air with refrigeration technology.
The cold press is used to slowly straighten and level the uneven plate with slow force! The hot press uses strong and heat to instantly cure and strengthen the board and glue!
The maximum pressure is 0.8MPA, and it is enough to choose a lot of large cubes according to the air supply flow required. The cold presses used by sheet metal companies are basically used to correct the sheets. The presses are not very large, but the pressing time is basically between 20 minutes and 60 minutes. , and some even longer! This process is mainly to provide good conditions for the subsequent work of the hot press!
Application field: used for furniture production, processing and production of wooden plywood pressing parts such as speakers, wood industry, decoration, plastic, flat plywood, plywood, particleboard, veneer and so on. With high production efficiency and good quality, it is suitable for the production of wood products in various furniture production units and other industries.
Pre-pressing is a new process commonly used in the modern plywood industry. And in order to meet the requirements of the pre-pressing process, the adhesive should have initial viscosity. At present, a certain amount of fillers (such as soybean flour, wheat flour, etc.) that can play a tackifying role are added to the adhesive, or a certain amount of polymer is added to the urea-formaldehyde resin. methods such as vinyl alcohol. The pressing process includes slab pre-pressing and hot-pressing gluing, which is a key process in the manufacture of plywood. Before the slab enters the hot press for hot pressing and gluing, it is pressed in the cold press for a short time to make the veneer basically bond as a whole.
The veneer hot press used in the furniture industry is basically suitable for the size of wood-based panels (1220x2440mm). The board surface pressure is usually 0.2~0.4MPa and the corresponding total pressure is 120T. In addition to the main technical parameters such as pressure, number of layers, and surface pressure, there are other technical parameters such as opening, closing time, heating temperature and productivity, which should be determined according to different process requirements. The working process of the hot press for veneering can be divided into five processes: closing, boosting, maintaining pressure, depressurizing, and descending. The host of the press can be divided into three parts from the realization of functions: heating system (providing heat source), hydraulic system (providing pressure and controlling the action of the press) and the press body (frame, control part).
1. Heating system of plywood hot press machine
(1) Comparison of heating methods
The heating method affects the temperature selection, process control, and quality of processed products when the hot press is used.
The traditional heating methods are steam heating and electric heating. Steam heats up quickly, but it needs to be equipped with a pressure boiler. The pipeline pressure is high, and the steam is easy to condense into water, causing uneven temperature on the plate surface; electric heating has the characteristics of fast temperature rise, high heating temperature, and easy control, but it consumes a lot of power The cost is high, and there are disadvantages such as the failure of the resistance wire during specific use, which is not easy to replace.
The advantages of heat conduction oil heating are: high heat capacity, uniform temperature, it can be heated to a very high temperature under normal pressure, and the heat loss is small
It can reduce the production cost, but its disadvantage is that the heating speed is slow and it is not easy to control the temperature. In the furniture industry, the general hot pressing temperature should be
When the demand is not high, the hot water circulation boiler can also achieve satisfactory results, and the fixed investment and operating costs are very low.
(2) Performance of hot pressing plate
The performance of the hot press plate can be evaluated from several aspects. First, the use of the press plate material, then the processing accuracy, and finally the arrangement of the medium channels in the hot press plate.
The hot-pressed plate is generally made of a whole piece of pressed steel plate through deep hole drilling, and is mainly heated by dry oil and steam: the other isThe form of aluminum plate attached to the surface after welding the pipeline is mainly used for electric heating. Using the whole steel plate can avoid oil leakage caused by poor sealing, and has high rigidity and strength, but the hot-pressed plate is thicker; the latter is usually in the form of a thin plate, and due to stress generated during welding and processing, high processing accuracy is required.
The hot-pressed plate is thin and easy to preheat and control the temperature, but it has high requirements for the processed parts. The uneven thickness of the workpiece will cause the deformation of the platen and affect the quality of subsequent processing; the thicker hot-pressed plate is beneficial to increase the heat capacity and improve the strength and rigidity. But it will increase the size of the press and consume more steel.
During manufacturing and processing, it should be ensured that the flatness of the hot pressing plate and the upper and lower surfaces have sufficient parallelism. The flatness tolerance of the hot pressing plate should be within the range of 0.1-0.18mm, and the parallelism tolerance should be within the range of 0.15-027mm. The surface of the pressing plate The roughness is 3.2um. The temperature difference should not exceed 2-3°C in the entire width of the hot pressing plate. If the temperature difference is too large, the moisture content will be uneven, the product will warp easily, and the strength and appearance quality of the product will be affected.
The heating channel through which the heat medium flows in the heat press plate is generally not paid attention to by people in the furniture industry. The correct circuit design should be based on the principle of facilitating the flow of heat medium, facilitating the uniform temperature rise of the plate surface, and reducing the leakage of heat medium. For the small press hot plate used in the furniture industry, the design of single channel and double circuit is generally adopted, which can meet the requirements of use.
(3) Connection and sealing
The use of suitable connection methods and sealing elements is of great significance for heat transfer under high temperature and high pressure. At present, the connecting pipeline of the hot plate is basically made of hose, which makes the connection very convenient. In China, mainly metal hoses are used, and some manufacturers use imported Teflon hoses. Both methods can be used. The fatigue resistance of Teflon hose is better than that of metal hose. Asbestos rubber sheet is traditionally used as the gasket material, and new materials such as polytetrafluoroethylene and wound graphite have better sealing effects.
2. Control system of plywood hot press machine
The control system of the hot press mainly controls the work of the heating system and the hydraulic system, and its sensitivity and accuracy directly affect the accuracy of the press. Due to the complex composition of the control part, it is usually a problem-prone part. For presses with complex functions, such as vacuum lamination and veneer presses, many domestic press manufacturers directly import foreign control systems, and at the same time reduce the use of low-reliability control components such as solenoid valves as much as possible in the press.
3. Hydraulic system of plywood hot press machine
(1) Technological requirements of the hydraulic system
The hydraulic system of the hot press has two basic work requirements: applying pressure to the workpiece and driving the hot pressing plate to achieve specific movements. The stability of fast closing and pressure holding is an important index to evaluate the performance of hydraulic system.
The heating and curing of the glue should be completed in the pressure holding stage when dry veneering, so the fast closing speed is beneficial to the process and efficiency. On the one hand, it can reduce the heating of the slab under non-pressure and prevent the surface of the slab from losing too much water. , cause warping, and also prevent the pre-curing of the glue and reduce the quality of the veneer: on the other hand, it can shorten the auxiliary time and improve the productivity of the press. In order to make the opening and closing of the press stable, a mechanical synchronization device is generally provided or a hydraulic system is used to maintain synchronization.
(2) hydraulic cylinder
The hydraulic cylinder is the core part of the hydraulic system. At present, most wood processing presses use plunger hydraulic cylinders. Large-diameter cylinder plungers are mostly made of alloy casting, which is characterized by high hardness, thick hardness layer, scratch resistance, and excellent performance. Dry carbon steel heat treatment column
Plug: small-diameter cylinder plunger, mainly made of carbon steel heat-treated surface with hard chrome plating, and the surface hardness layer is thin.
Since the hot press usually requires a fast opening and closing speed and withstands impact pressure, the cylinder body must be made of higher strength materials. For ordinary hydraulic cylinders with small diameter and long strokes, seamless thick-walled steel pipes can be used to manufacture them. Casting or forging cylinders can be used for some demanding cylinders.
Usually, the working surface of the hot press used in wood processing and furniture manufacturing is relatively large. In order to make the pressure distribution uniform and consider the rationality of the structural layout, most of them adopt a multi-cylinder structure.
There are not many problems in the production of the heat press itself, but a large part of them is caused by the hydraulic system, such as oil leakage and failure to maintain pressure. A lot of knowledge and requirements about the hydraulic system cannot be fully stated here, but it must be paid attention to when selecting.
1. Precision platen working table,it can make the pressure distribution of the whole table evenly and the flatness of the pressure maintaining surface for a long time.
2. Easy and convenient control panel easy for operation.
3. Timing control,Set the appropriate time, when the set time is reached, the pressure plate will automatically release and beep to remind the operator.
4. Thick steel sheet and tough machine body stable and durable.
1. Our machine's Steel plate are based on the pressure's requires to custom, to achieve our commitment pressure, quality assurance.
2. The use of hydraulic system work, lifting speed, pressure uniformity, high efficiency.
3. Our machine's most of electrical components selection of Schneider or Chinese famous brand, main parts have option has CE authentication products.
4.Fast and efficient pressing, emergency safety braking, trip limited device.
5.Automatic compression and unloading pressure function.
6.Workbench height convenient worker operation
7.With overpressure automatic control circuit and pressure off the oil protection, automatic lift, automatic oil off.
8.The upper and lower pliers by the gantry milling finishing, to ensure absolute formation.
Cold press machine belongs to the pressing machine.Plywood Cold press machine is mainly used to press the gluing veneer, so make gluing veneer shaping, and then put into the hot press machine to press.
It is important to improve the quality of plywood, and it is an important step.Plywood Cold press machine in general consists with the frame, fixed beam, moving beam, the plate device, cylinder and hydraulic system, electric control system components.
Plywood Cold press machine is also called pre-press machine, which is the auxiliary machine in plywood production line, which is used to shorten the cycle time of hot press and improve the quality of plywood before gluing plywood.
A cold pressmachine is a heavy duty machine that will make your production line more efficient and profitable.
This is a machine you can expect to have for a very long time and should be seen as an investment instead of a cost.
It is well known that cold gluing is the best solution for certain types of applications.
The cold process can produce a finished product with better characteristics than those which can be obtained by hot pressing.
One of the limitations of a cold press is the long curing times of the glue.
This takes much longer than the hot press.However, this limitation is being overcome by the new generation of glues.
Glue curing time has been greatly reduced when used within a cold press.
Cold presses use ambient platens, or rollers to generate force. The amount of temperature, pressure, time and moisture content all factor into how the process works.
Cold presses can also be more economical to run then hot presses. Which is a bonus when energy prices are at their highest.
Hydraulic Cold presses create greater forces to produce products that may need shaping. Used for making doors, room dividers and much more.
These machines can be used to work with plywood, MDF sheets and various other surfaces.
Cold presses allow you to press in a stack using cold curing adhesives. They are used for veneering chip board and MDF panels, laminate panels, doors and more.
Cold presses are popular in the furniture industry.
Whereas hot presses are popular in, but not limited to, the marine industry for making polymer fenders.
Hot pressing on the other hand have become very mature in terms of technology after years of development. The operation of the machine is also very simple. The temperature, pressure and time can be set, and the degree of automation is superb.
When it comes to heat pressing of plywood, you typically have a choice between hot pressing and cold pressing. Both are used for flattening, bonding, veneering and pressing of wood sheets. Choose one that fits your requirement of intended application.
Cold pressing normally takes a longer time, which is about 3-4 hours or so. For applications, cold plywood pressing machines are mostly used in the production of wooden cabinets and doors. As the name implies, the cold press plywood press machine is only pressed at room temperature, and the hot press can heat the sheet, the temperature can be up to 300 degrees, and the flatness of the hot press is higher.
