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Trilogy of Plastic Wood Composite Material Manufacturing Technology Progress
The manufacture of plastic wood composite materials is different from solid wood materials, and it cannot be manufactured according to the manufacturing ideas of plastic materials. For a long period of time, the development of plastic wood composite materials was greatly restricted by technical conditions, and the advancement of materials and market demand forced the development of plastic wood composite material manufacturing technology. The development of plastic wood material manufacturing technology is mainly embodied in three aspects: sheet manufacturing technology, profile manufacturing technology, and progress in connection and assembly technology.
Sheet manufacturing technology
In the 1990s when plastic wood composites were not well-known to everyone, people were inspired by other man-made board manufacturing methods and began to use die-casting to manufacture material preforms and assemble the preforms into simple board materials. Some people use the hot pressing method to manufacture the plastic wood composite board table top, in order to increase the strength of the board, a mesh layer made of glass fiber is arranged in the middle of the board. With the emergence of plastic wood composite extrusion technology, people began to combine single-screw extruders, twin-screw extruders and plate molds at the beginning of this century to manufacture plastic wood composite material plates.
Profile manufacturing technology
Plastic wood composite extrusion molding technology is widely used in the manufacture of profiles. Plastic wood composite profiles are mainly used to manufacture materials such as legs and feet, cabinet eaves, decorative edges, and door frames. Based on the processing method of extrusion molding, plastic wood composite material profiles can obtain higher production efficiency, and the current manufacturing technology of plastic wood composite profiles is relatively mature. By designing different cavities for the profiles and designing and improving the die, the material profiles with different shapes and meeting different needs can be produced. At present, the research and development of plastic wood composite profile manufacturing technology mainly focuses on formula improvement, material rheology, mold size, process parameters, cavity design, etc. Plastic wood composite profiles are mainly used to manufacture materials such as backrests, legs and feet, headboards and mirror frames, etc., and are especially suitable for manufacturing materials with Baroque artistic style. The plastic wood composite material profile can be manufactured by molding or injection molding. During compression molding, the plastic wood composite material is first placed in the mold cavity, the mold is closed, and the properties of the material are changed under the action of heat or pressure, and a shape that matches the shape of the mold is molded in the mold. Using this molding method, organic curved surfaces can be manufactured, and the surface pattern texture can be processed at one time. The injection molding process is to inject the molten plastic wood composite material into the mold cavity with high pressure, and after cooling and demolding, it is made into a product that matches the shape of the mold. The injection molding process can obtain a variety of product shapes, which can be used not only to manufacture complete materials, but also to manufacture material parts with complex surfaces. However, since the fluidity of plastic wood composite melt is significantly lower than that of homogenous plastics, injection molding and even compression molding of plastic wood composite profiles are difficult, and further research and development are needed.
Connection assembly technology
The structural connection and assembly of plastic wood composite materials are important issues worthy of attention in manufacturing. Material assembly needs to consider material firmness, disassembly and assembly efficiency, and installation efficiency. Material structure connection includes fixed connection, movable connection between plastic wood material parts, and connection between plastic wood material parts and other material parts. In the structural connection of materials, in addition to considering the functional needs of the material, the place of use and the stress, the nail holding force, supporting span, viscoelasticity and creep of the material should also be paid attention to. Different plastic wood composite materials have obvious differences in mechanical indicators, and different connection methods and structural treatment methods need to be adopted according to different materials. On the one hand, the methods such as mortise joints, nail joints, riveting joints, connector joints, eccentric joints, etc. applicable to solid wood materials and plate materials can be partially applied in the field of plastic wood material manufacturing. On the other hand, it is necessary to adapt to the characteristics of plastic wood composite materials to develop high-performance welding, gluing, plug-in, screw connection, pull-hanging connection and new movable connection methods.