Publish Time: 2023-12-11 Origin: Site
Plywood is a three-layer or more plywood made of logs rotary cut into veneers or planed into thin wood and then glued with adhesive. Usually, an odd number of layers of veneers are used, and the fiber directions of adjacent layers of veneers are aligned vertically and glued together. Covering plywood with upper and lower layers of laminated paper is called laminated plywood. Laminated panels are mainly used on construction sites, house decoration, and other outdoor construction purposes. It is difficult for that layer of coated paper to bond with cement, so it is mainly used at construction sites. The layer of coated paper on the surface is made of special paper impregnated with amino resin (mainly melamine resin) or phenolic resin, and dried to a certain degree of solidification.
Film-faced plywood is commonly used in the construction industry as building formwork and furniture panels. A heat press applies heat and pressure to each layer of plywood to bond them together. Therefore, choosing the right heat press tonnage is very important to ensure the quality of the board and the strength it can withstand.
When purchasing a hot press machine, the thickness and density of the veneer raw material, tree species, size, glue, heat, etc. are all important factors. If the tree species of the veneers are of high density, you can choose a press with a higher tonnage to ensure a stronger bonding effect between the veneers. Tree species include birch, eucalyptus, rubber wood, poplar, meranti, etc. The size of the board will also affect the required tonnage, because for example, for a 4*10 ft, 5*10 ft, 5*12 ft plywood you will need a higher tonnage of pressure to exert sufficient pressure on the entire board surface.
An important factor in choosing which glue to use. Different adhesives have different hot-pressing requirements for temperature and pressure. Some glues require higher pressure and higher temperature to cause chemical reactions in the glue. In addition, the operating temperature of the hot press, as well as the lifting speed and closing speed of the hot press, are all within the scope of consideration. From physics, it is known that temperature and pressure complement each other.
Also, when choosing a plywood hot press, we would recommend that the factory find a production consultant or factory director in advance, because when choosing a hot press, the factory director will take into account the production process, the boards produced, and the equipment. The degree of automation, the working habits of workers, and whether local raw materials can be hot-pressed and whether the strength and hardness can meet the standards required for construction, etc.
In short, when purchasing a heat press, the tonnage of the heat press is the first key factor to consider. It will directly affect the strength, hardness and durability of the laminated plywood.
Different tree species, plywood specifications, and plywood uses are different, and have different requirements for the performance and tonnage of the hot press. For example, plywood used on construction sites, container plywood, wooden flooring, furniture panels and specific plywood used by airlines. Therefore, it is important to calculate the corresponding tonnage. Otherwise, the tonnage is not enough and the plates cannot be pressed firmly. If the tonnage is large enough, the sheet will be crushed. For example, there are 3 oil cylinders, the bore diameter is 320mm, the working pressure is 15M, and the optional hot press tonnage is 450 tons.
During the use of a heat press, cushioning pads are usually required when pressing floors, particleboards, wooden doors, and furniture. The function of the cache pad is to evenly transmit the pressure and temperature of the hot plate, which can make the bonding between the paper veneer and the substrate denser and uniform, thus improving the quality of the veneer.
In the hot press working combination, the cushion pad is clamped between the hot press plate and the template. During installation, the hot press cushion pad must be placed flat and evenly on the hot press machine. The cushion pad must be placed in order from top to bottom. Installed between the heat transfer plate and the stainless steel template of the heat press. Do not fix it first to prevent debris from being brought into the pavement. Clean the surface of the hot press before leaving any debris, oil, or other metal objects. Preheat and press for 30 minutes according to the work requirements, and the temperature will rise to 60-80. degrees Celsius, and increase the pressure to bring the pressure plate into a slightly closed state. During the fixing process, you only need to fix the four corners in the length direction. It is best not to fix the width direction, and then fix the four corners at equal distances before putting it into use. After more than 200-300 sheets were pressed, the cushion pad shrank slightly due to heat, and it was necessary to readjust the tension of the cushion pad after shutting down the machine. Press and paste more than 200-300 sheets again before adjusting again. During use, one cushion pad cannot be used continuously with multiple templates, which will cause the cushion pad to twist when changing templates, affecting the life of the cushion pad. Some manufacturers have begun to implement a stainless steel formwork with a buffer pad, so that the buffer pad can be maintained while replacing the steel plate. Avoid continuous operation of the steel buffer pad at high temperatures of 180-220 degrees Celsius, which will reduce its lifespan.
In China, there are many materials for cushioning pads, such as silicone, chemical fiber, wool felt, asbestos, etc., but the first three are the most commonly used. When making a selection, the factory must choose a suitable cushion pad based on the hot-pressing process and the finished board produced, such as the temperature of the hot pressing board, the quality of the board, etc. Silicone buffer pads are available in 7X8, 7X9, 9X11, 9X13 and other specifications; if the temperature is high, you can choose silicone or chemical fiber material; if the temperature is low, you can choose wool felt cushions and copper chemical fiber cushions.
What are the differences and choices between chemical fiber cushion pads, silicone cushion pads, wool felt cushion pads, all-copper cushion pads, and asbestos cushion pads?
Typically used in heat-pressed construction plywood, synthetic fiber cushioning pads are preferred because of their excellent heat resistance and durability. They withstand high temperatures without degrading or melting. Smooth and even pressure distribution can also be achieved during hot pressing. Additionally, they are cost-effective and easy to replace when worn.
Silicone cushioning pads are made from heat-pressed furniture panels. This places high demands on the board, which is highly heat-resistant and offers a non-stick surface with good shock-absorbing properties, making it suitable for use with delicate or sensitive materials. However, their cost will be relatively high.
When selecting stainless steel plates, it is necessary to select the correct stainless steel plate material and determine the thickness suitable for the specific application. Therefore, when selecting stainless steel plates for hot pressing, several factors must be considered.
The requirements for the finished board. If it is a finished board with melamine paper pressed on it, the choice of material and thickness needs to be based on the manufacturer's requirements. For example, if the material is 304, the thickness is 5.0/5.0MM. If it is the layer of veneer pressed on the surface of the furniture board, the material you can choose is 304, and the thickness is 3.0/3.0MM. For thicknesses above 3.0, you can choose to lock them with screws to facilitate maintenance and replacement. Because the textures on the surface of stainless-steel plates are different, some are smooth, mirror, and various patterns of other countries' preferences.
Secondly, there are different grades of stainless steel available, each with its own unique properties and characteristics. The most commonly used materials for heat press applications are 304 and 316 stainless steels. Both materials have excellent corrosion resistance, high temperature strength and good formability.
The choice of thickness depends on the specific application and the pressure and temperature levels involved in the pressing process. Under certain circumstances, if a stainless-steel plate with a thickness of 1.7/1.7MM is used, the requirements of ordinary plywood can be met. The thickness of the stainless-steel plate will also affect the heat transfer and distribution during the hot-pressing process. Thicker plates may require longer heating and cooling times, while thinner plates may heat and cool faster. Therefore, the selection of thickness should also consider the heating and cooling capabilities of the heat press, as well as the cycle time required for the pressing operation.
Concrete Formwork: Membrane plywood is made by bonding a phenolic resin-impregnated membrane to both sides of a plywood panel, creating a smooth, waterproof surface. The film enhances the durability and longevity of plywood, making it suitable for harsh construction environments.
Unlike regular plywood, laminated plywood is highly resistant to concrete and is therefore often used for panel formwork.
Coated plywood is widely used in the building, construction and vehicle industries for the manufacture of shipping equipment containers, loading platforms, truck and trailer floors and vans. This material is also used to make furniture such as chairs, tables, sofas, beds, etc.
Film-coated plywood is mainly used as a formwork material for pouring concrete. It provides a smooth and consistent surface, ensuring a high-quality finish on concrete walls, columns, beams and slabs. The membrane on the plywood acts as a barrier, preventing moisture from penetrating the wood and affecting its strength or causing warping. Construction and Remodeling: Clad plywood can be used in a variety of construction projects such as building walls, ceilings, roofs, and floors. It is used as a structural material for framing, sheathing, and general carpentry work. Exterior Applications: Due to its durable and weather-resistant properties, laminated plywood can be used in exterior applications. It is suitable for projects such as external cladding, hoardings, fencing and signage.
Formwork: Coated plywood is commonly used in formwork applications as a temporary support system for vertical or horizontal concrete pours. It provides stability and structure to the concrete until it sets and gains sufficient strength.
The most common plywood sizes are 4 x 8 , 4 x 10 feet,4*12feet ,5*12feet . Softwood is also available in plywood sizes 2 x 2 feet, 2 x 4 feet, and 4 x 4 feet.
The most commonly used thickness range is from 1⁄8 to 3.0 inches (3.2 to 76.2 mm). The sizes of the most commonly used plywood sheets are 4 x 8 feet (1220 x 2440 mm)[20] which was first used by the Portland Manufacturing Company, who developed what we know of as modern veneer core plywood for the 1905 Portland World Fair. A common metric size for a sheet of plywood is 1200 x 2400 mm. 5 × 5 feet (1,500 × 1,500 mm) is also a common European size for Baltic birch ply, and aircraft ply.[21]
Sizes on specialised plywood for concrete-forming can range from 15⁄64 to 13⁄16 in (6 to 21 mm), and a multitude of formats exist, though 15 × 750 × 1,500 mm (.59in × 30 × 59 in) (19/32in × 2 ft-6in × 4 ft-11in) is very commonly used.
Aircraft plywood is available in thicknesses of 1⁄8 inch (3 mm) (3 ply construction) and upwards; typically, aircraft plywood uses veneers of 0.5 mm (approx 1/64 in) thickness although much thinner veneers such as 0.1 mm are also used in construction of some of the thinner panels.
Premium Film Faced Plywood can be used approximately 8-12 times which is best for the market that requires strict quality while having to maintain the most competitive pricing. With 100% grade core A and % WBP Melamine up to 18%.