Some understandings of special wood-plastic production equipment

According to reports, the "wood-plastic composite extrusion machine" in the "Environmental Protection Equipment and Catalogue of Products Encouraged by the State (2009 Edition) for Soliciting Opinions" is also on the list. This is China's wood and plastics that are agitated on the eve of the eruption. In terms of industry, it is a good thing. However, there are always two sides of the matter. For the domestic-made wood-plastic special production equipment that has just been out of the embarrassment period, it is necessary to face up to the many deficiencies that it faces. I hereby make the following observations that are just right for you.

Analysis of Production of Special Wood-plastic Extrusion Equipment

In recent years, wood-plastic materials rely on the encouragement of the national circular economy policy and the dual power of the company's potential benefit demand. Especially after the wood and plastic materials have successfully entered the Beijing Olympic venues and facilities construction, the national “wood-plastic material heat” volt He is in the ascendant. According to incomplete statistics, as of the end of 2008, there were more than 200 R&D, production, sales, and supporting enterprises and institutions connected to the wood-plastic composite material industry chain in China, of which equipment manufacturers (including molds) accounted for 1/4 of the total. about. With the gradual expansion of the wood-plastic market, the domestic production capacity of wood-plastic materials has also been greatly improved. The annual output of wood-plastic products has reached about 150,000 tons, ranking second in the world; the level of process technology of individual manufacturers has jumped. Forefront of the world, its innovative products have repeatedly attracted foreign counterparts. It should be said that this is a hard-won, exciting situation. However, it should also be noted that the development of China's wood and plastics industry is unbalanced, and some links still have many problems. According to the author, the lag in the R&D of special equipment for wood-plastic materials production is a bottleneck restricting the development of wood-plastic products in China.

"Wood-plastic special production equipment" should be a term that has only appeared in recent years, although China's wood-plastic industry has gone through 10 years of history. One of the undoubted facts is that almost none of the manufacturers currently providing extrusion equipment for wood-plastic materials are not inextricably linked to the manufacture of plastic processing equipment. Of course, it is not that plastic processing equipment cannot be used to manufacture wood-plastic material production equipment, nor is it impossible to produce an excellent wood-plastic material production equipment by producing plastic processing equipment. Judging from the development track of the overseas wood-plastic industry, it is also similar to this. The problem is that some of the so-called scientific researchers and even professional manufacturers currently active in the domestic wood-plastics industry actually do not fundamentally solve the core issues of wood-plastic materials preparation, but they must be able to win the first “star effect” of wood-plastic materials. Grab market share. Therefore, some companies’ equipment can be launched without recourse. When a technical problem is encountered, it is at best “a headache, a foot massage,” as long as you can squeeze out something and squeeze out what kind of things. It may no longer be the case that the parties are willing to investigate.

The author had been invited to inspect a wood-plastic material production plant in the Central Plains region. The factory invested nearly 3 million yuan to purchase the so-called advanced wood-plastic extrusion processing equipment. Extruded plastic products are still barely enough to extrude qualified wood-plastic materials. Basically, it is a pile of scrap iron. The investors were sorely attentive, and the onlookers were also dismayed! This kind of situation was often staged in the early days of the development of wood and plastic products in China, and gradually decreased. It should be said that people who are willing to join the ranks of wood and plastic production and strive to learn and progress are still very much in demand. The author once exchanged opinions with a chairman of a large-scale equipment manufacturer on the research and development of special wood-plastic production equipment. Bi Jun believes that wood-plastic materials are a new area. Don't care about it, you don’t care too much, you don’t care too much, you just walk away. Take a look. It is reported that this is a "walk away and see", this factory every year sales of wood plastic equipment is also more than 20 million yuan, although there is a larger distance compared with its main business, but it is not a "drizzle." Therefore, the author believes that the major problems faced by domestic wood-plastic extrusion equipment manufacturers are "unsatisfactory," and the crux lies in the "diligence in harvesting and neglecting cultivation."

Some features of wood-plastic special extrusion production equipment

Although the processing methods and main equipments of wood-plastic materials are similar to those of plastics processing on the surface, as an emerging industry with marginal, multi-faceted and specialized characteristics, its equipment, technologies and processes involve polymer chemistry and material rheology. , Wood chemistry, physical chemistry, fine chemicals, precision machinery, hydraulic transmission, vacuum technology, thermal conductivity, fluid mechanics, sensing technology, electronic automation and microcomputer programming and many other disciplines and disciplines, its production equipment has its own distinct characteristics. After several years of exploration and tempering, it has been proved that as a new type of material with independent properties, wood-plastic materials are much more difficult to process than ordinary plastic products, and production equipment is also increasingly inclined to specialization and specialization, and many New features and requirements, such as:

1. Selection requirements: When producing wood-plastic products, due to the addition of a large amount of biomass fibers, the wear of barrels and screws in the equipment is increased. Therefore, the materials used in the production of wood-plastic materials must use higher strength. More complex metal materials, such as tungsten alloy bimetal coating materials, to enhance wear resistance and extend equipment life.

2. Structural adjustment: Because wood-plastic materials contain a large amount of wood powder, resulting in poor fluidity of the melt, extrusion resistance increases, the screw torque increases, so in the design of the screw is now used more rapid compression and melting, strong driving force Multi-stage cone double structure to meet the same good plasticizing and conveying function at lower temperature and rotation speed.

3. Design changes: Due to the poor fluidity of the extruded materials during the preparation of wood-plastic materials and the difficulty in cooling, conventional molds and styling equipment have been unable to meet the production needs, which makes the design of the machine head in addition to ensuring a smooth transition of the flow path and a reasonable flow distribution. In addition, it is also necessary to design the head's high-pressure resistance and temperature control precision, and reasonably arrange the heating and cooling device of the head to ensure the extrusion speed and product quality of the wood-plastic products.

4. Component improvement: Due to the small proportion of wood powder and large amount of filling, the volume of the loading area for wood-plastic equipment is about 1/3 larger than that for plastic machinery. In addition, the wood-plastic products are mostly complex profiled structures and it is difficult to control the temperature. Especially in the cooling process, in addition to the conventional water-cooling method, special cooling devices are required for products with complex structures.

5. Dedicated screw design: Due to the thermal sensitivity of wood flour, it will degrade at high temperatures, and its poor heat exchange and non-flow characteristics make it difficult to plasticize wood plastic melt. Therefore, the production of wood-plastic products can not follow the plastic processing technology, only by increasing the temperature of the barrel to achieve plasticization, and requires the design of a higher shear screw with the characteristics of the melt characteristics of wood-plastic materials, the use of cutting heat The wood plastic melt is plasticized at the temperature at which the wood powder is degraded.

6. Special planes: There are many specifications for wood-plastic extruders. In theory, the performance of each model is the same. However, in actual production, often due to the intersection of various factors, the adaptability of the same model of equipment to the same mold will be quite different. This requires the operator to continuously adjust the equipment parameters according to the product status to ensure the product quality. Under the current technological conditions, the production of wood-plastic materials is still suitable for special purpose machines.

7. Process and equipment integration requirements: This is the most scratching problem for the manufacturers of wood-plastic equipment factory, and it is also the technical node for solving the special equipment for wood-plastics. With the current conditions for the preparation of wood-plastic materials, it is required to configure the production line and the mold with the process recipe as the core, and generally it is not possible to adjust the recipe to adapt to the equipment. In other words, a processing center is only responsible for parts processing, and it can be used regardless of whether the parts come out; and the wood-plastic production equipment must not only produce wood-plastic products, but must also ensure the quality and performance of the products, otherwise it is a pile of waste.

Expectation for Domestic-made Wood-plastic Special Production Equipment

The special production equipment for wood and plastic products is tied to the “pedigree”, but also because some individual technicians still use some theories and methods of plastic processing, coupled with the lack of input funds, strength and other factors, resulting in long-term domestic production of special equipment for wood and plastic No progress, no refunds. However, under the condition that the entire industry is not mature enough, only dozens of patent authorizations involving wood-molded molding equipment in China are no less than dozens. With the facts that the author understands, most patents still have only research significance and have virtually no practical value. At present, various types of wood-plastic materials production equipment are basically transformed from plastics processing machinery. All data are not subject to national standards and there is no credible comparison system and reference system. Both buyers and sellers act on the basis of experience, and the technology during the execution of the contract. Disputes are common, and individual places even said that "a contract with a petition," said that this can not be said that China's wood and plastic development in a big legacy.

At present, some manufacturers of wood-plastic equipment have thrown the “hybrid and low energy consumption” hydrangeas at any time, attracting some newly-introduced investors to purchase their equipment. The actual problems are: the output of wood-plastic extruder is affected by the raw materials and shapes of the products being extruded. The impact of many factors, such as performance requirements, should always be a dynamic indicator rather than a static data. If we only emphasize the size of output, regardless of the quality of the product, it will be meaningless if we squeeze out large quantities. Some foreign equipment is just under the banner of "yield" and domestic enterprises are repeatedly taken advantage of. The technical requirements for the special wood-plastic production equipment should be: under the premise of compounding the wood powder with higher filling amount, ensure that the material still has high fluidity and good plasticization, so that the plastic melt can be fully The wood flour is evenly bonded to achieve the purpose of common recombination, excellent mechanical properties are obtained, and products with excellent functions and high added value are manufactured with low consumption.

At present, there are already a large number of domestic manufacturers claiming that they can manufacture wood-plastic production equipment, and their influence and role have been gradually expanding. However, the majority of equipment manufacturers have limitations in terms of personnel, technology, capital, and scale in their development, and their development momentum is not very smooth. Another phenomenon that we must notice is that some foreign special equipment manufacturers for wood and plastic products, such as: American Milacron Cincinnati, Davis Denton, Tekepas, etc Material market. If we do not rely on decisive measures and corresponding measures in this field to become self-reliant, the emerging Chinese wood-plastics industry, which is one of the few in the domestic manufacturing industry to have equal dialogue with Europe and the United States, will be squeezed without reason.

It should be acknowledged that at present, the entire wood-plastics industry is in the stage of development and exploration. Immature places are inevitable. We should face up to the shortcomings, learn from each other and catch up. According to current conditions, it is predicted that by the end of the “11th Five-Year Plan”, China’s wood and plastic production and sales volume is expected to exceed 300,000 tons, with an output value of 5 billion yuan. By the 12th Five-Year Plan period, China’s total output of wood-plastic materials is expected to catch up. On the United States, it entered the ranks of the world's largest wood-plastic countries. With the current production capacity of about 150,000 tons in China, the development space for its production equipment is unprecedentedly broad. We believe that through the efforts of the majority of people in the wood-plastics industry, China Wood Plastics is fully confident that under the guidance of the national circular economy policy, we will continue to improve the level of equipment manufacturing and material production, and make contributions to becoming the world’s largest wood-plastic power as soon as possible!