Current situation and development direction of hol

2022-10-14
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Current situation and development direction of hollow plastic molding machines in China's packaging industry (IV)

2 Injection blow large-scale hollow plastic molding machine

injection blow large-scale hollow plastic molding machine is developed on the basis of extrusion blow large-scale hollow plastic molding machine, which is suitable for molding single-layer large-scale hollow plastic products. Injection blow large-scale hollow plastic molding machine is a comprehensive hollow plastic molding machine that combines the injection plasticizing mechanism of the injection machine with the blow molding and clamping mechanism of the extrusion blow hollow plastic molding machine. It absorbs and gives full play to the respective advantages of the two machines to achieve high parison weight repetition accuracy, high plasticizing capacity, short color and material change time, and high strength of the melt fusion seam area. Extrusion and blowing large-scale hollow plastic molding machines generally use the storage head, which has complex internal structure and many parts. Therefore, from the characteristics of the storage head itself, there are inevitably shortcomings such as long time for color change and material change, inaccurate measurement accuracy and so on. The head of the injection blow large-scale hollow plastic molding machine separates the two functions of material storage in the storage head of the extrusion blow hollow plastic molding machine and injection of extruded embryos, which are completed by the injection plasticization mechanism. In this way, the head has the advantage of easy color and material change of the continuous head. At the same time, the structure of the head is simplified, coupled with a reasonable flow path design, It fundamentally solves the defect of long time for color change and material change of the storage head of the extrusion blow hollow plastic molding machine, and does not affect the installation of the parison wall thickness control servo system. According to the characteristics of gap forming of large hollow parts, Shanghai huawang Industry Co., Ltd. developed φ 95 screw injection blow large hollow plastic molding machine, molding a bag only 18 seconds, it is worth promoting in the field of hollow plastic molding machine. If the injection volume needs to be increased and the plasticizing quality needs to be improved, the injection plasticizing mechanism can adopt a composite mechanism that combines extrusion plasticizing and plunger with pre plastic injection. The injection blow large hollow plastic molding machine can also be used to mold 20L PC bottles and PET bottles for drinking fountains

3. "One step" injection, pull and blow hollow plastic molding machine

"one step" injection, pull and blow hollow plastic molding machine, small and medium-sized machines mainly shape pet carbonated beverage bottles and mineral water bottles, and large machines mainly shape PC pure water bottles. The "first step" injection, drawing and blowing hollow plastic molding machine is an efficient equipment that continuously carries out the processes of injection molding, heating molding, stretching molding, blow molding and demoulding of molded products on the same equipment that silicon carbide cutting edge material is being replaced by diamond wire. The "one-step" injection, pull and blow hollow plastic molding machine can be divided into "three station" injection, pull and blow hollow plastic molding machine represented by Aoki Ku of Japan and "four station" injection, pull and blow hollow plastic molding machine represented by Nissei of Japan. The main difference between "three stations" and "four stations" is that "three stations" is to complete the injection and heating billets in one process, and "four stations" is to complete the injection and heating billets in two processes. At present, the injection, drawing and blowing hollow plastic molding machines used in China are basically the equipment of Aoki and Nissei of Japan, which is worth pondering by every hollow equipment manufacturer. The injection and blowing hollow plastic molding machine has its own characteristics, which cannot be replaced by other bottle blowing machines. Foreign manufacturers are optimistic about the Chinese market. According to their estimates, the beverage packaging industry, the Chinese market also needs no less than 800 "one-step" injection, drawing and blowing hollow plastic molding machines for the production of PET bottles

3.1 at present, China's "one-step" injection, pull and blow hollow plastic molding machine development overview

China's plastic machinery plant "one-step" research and development of injection, pull and blow hollow plastic molding machine has a history of nearly ten years, following the path of Japan's Aoki solid "three station" and Japan's precision "four station" models. It is understood that China has no less than four plastic machinery plants put into research and development, But so far, no plastic machinery factory has been able to produce the injection, drawing and blowing hollow plastic molding machine that meets the product quality requirements. The quality of the products formed by the two injection, drawing and blowing hollow plastic molding machines displayed at the 6th Asia Pacific International Rubber and plastic industry exhibition in Shanghai in 2003 cannot meet the quality standard, which is specifically reflected in the uneven wall thickness. The "one-step" research and development of injection, drawing and blowing hollow plastic molding machine includes two aspects: host and mold. The plastic machinery factories that invested in the development of this product in the early stage had to basically give up this development because the products could not meet the quality standards. Now the new injection, drawing and blowing hollow plastic molding machine has made progress in the mechanical mechanism and control of the host, but it is not mature in the mold. The quality standard of injection, drawing and blowing hollow plastic molding machine is whether the molded products meet the quality standard. If the mold fails to meet the requirements, the products that meet the quality standard cannot be molded. Therefore, in terms of the overall technical level of China's injection, drawing and blowing hollow plastic molding machine, it is still in the development stage and cannot meet the requirements of commercialization

3.2 analysis of problems in research and development

after nearly ten years of research and development, why can't China's injection, pull and blow hollow plastic molding machine reach the commercialization level. The author believes that the main reasons are as follows:

3.2.1 misunderstanding of development ideas

only focus on host development and ignore mold development. The injection and blowing hollow plastic molding machine is a combination of the host and the mold. From the importance of the host and the mold to the whole machine, the host only accounts for 40% of the whole machine, while the mold accounts for 60% of the whole machine. The successful development of the host does not mean the successful development of the whole machine. Only the successful joint development of the host and the mold can we say that the development of the injection and blowing hollow plastic molding machine is successful. The key technology of Japanese Aoki solid "three station" and Japanese Japanese precision "four station" models is the mold, and some of our plastic machinery factories did not correctly recognize the relationship between the host and the mold in the process of developing the injection, drawing and blowing hollow plastic molding machine, only paid attention to the development of the host, but did not put the development of the mold in a more important position. This is the main reason for the failure

3.2.2 the technical level of the mold cannot meet the requirements

the mold of the injection, pull and blow hollow plastic molding machine is different from the injection molding mold, and has its own characteristics. In the mold of the injection blow molding machine, the key is the mold of the injection mold blank. The material of the mold has special requirements for its performance, with small coefficient of thermal expansion and contraction, high heat transfer efficiency and high heat conductivity. The structure of the mold is in the form of hot runner. Judging from the current mold technology level in China, it is still impossible to develop and manufacture molds of injection, drawing and blowing hollow plastic molding machines that meet the quality standards. It is understood that some mold factories do not know which material is used in the mold of the injection, drawing and blowing hollow plastic molding machine. How can they develop a mold

due to the lack of investment in the mold factory, the mold technology level cannot be developed. It is understood that foreign mold factories that develop and manufacture injection, pull and blow hollow plastic molding machines have their own injection, pull and blow hollow plastic molding machines, and the developed molds are tested repeatedly on the host until they meet the requirements, while no domestic mold factory purchases injection, pull and blow hollow plastic molding machines as trial production equipment for the development of injection, pull and blow hollow plastic molding machines

3.2.3 there is a lack of cooperation between the main engine factory and the mold factory

the development of the "one-step" injection, drawing and blowing hollow plastic molding machine, the main engine factory and the mold factory must cooperate, and both of them have their own division of labor to jointly develop and bear their own risks. This is the experience of foreign countries in developing the "one-step" injection, drawing and blowing hollow plastic molding machine. For example, Aoki Gu and Nissei companies in Japan have mold factories supporting them. The main machine factory puts forward the requirements, the mold factory develops them, and then hands them over to users. However, some of our main engine manufacturers do not know much about the mold of the "one-step" injection, drawing and blowing hollow plastic molding machine. In order to save the development cost, they make their own mold. As a result, not only the formed products fail to meet the quality standards, but also have a negative impact on the image of the main engine

3.3. Development direction

3.3.1 mold

mold is the focus of the development of "one-step" injection, drawing and blowing hollow plastic molding machine. The key point of developing the mold of the "one-step" injection, drawing and blowing hollow plastic molding machine is to develop the mold of the injection mold blank. The key point of developing the mold of the injection mold blank is the material of the mold, the design of the hot runner nozzle and hot runner, and the temperature control system. At present, when the mold of the "one-step" injection, drawing and blowing hollow plastic molding machine in China cannot reach the technical level, the main engine factory can cooperate with relevant foreign mold factories. As long as the mold reaches the due technical level, coupled with our host, it can be said that the "one-step" injection, drawing and blowing hollow plastic molding machine can go to the market

3.3.2 host

host performance has reached the basic performance requirements, but there is a gap with the equipment of Aoki Gu and Nissei. The key points of the development are:

high speed and positioning stability of the rotary table. The operation and positioning performance of the rotary table affect the forming efficiency. The injection blow molding machine is a high-speed molding equipment, and the high-speed operation of the rotary table is an indispensable part of high-speed molding. The operation of the rotary table must meet such requirements. It starts to rotate at a high speed. At about 100mm away from the next station, the deformation measurement system suddenly enlarges. The measurement system rotates at a slow speed at a certain speed, until there is no back and forth swing at the positioning point, no impact, and stable positioning. Judging from the operation of the host machine developed by each factory, the high-speed operation speed of the turntable is not enough, and the turntable swings back and forth when positioning at the positioning point of each station. It often needs to swing several times before positioning, which affects the production efficiency. The key to solve this problem is to improve the hydraulic and electrical control level and control accuracy

3.3.3 blow molding clamping mechanism

the blow molding clamping mechanism of Aoki Corporation in Japan has used the gear rack high-efficiency and high-speed synchronous clamping mechanism. The principle of this clamping mechanism is similar to the gear rack synchronous clamping mechanism of the extrusion and blow hollow molding machine. This clamping mechanism has high repetition accuracy for neutral energy, but we still use the obsolete inefficient one-way clamping mechanism without automatic centering performance or the clamping mechanism in which two templates operate simultaneously under the action of pressure oil, Follow the old path of similar machine manufacturers in the world. The running time of the rack and pinion synchronous clamping mechanism is reduced by 30% compared with that of the one-way clamping mechanism, and the energy consumption of the clamping mechanism is reduced by half compared with that of the two templates running simultaneously under the action of pressure oil

3.3.4 high speed, high efficiency, high quality and low energy consumption

the main advantage of the "one-step" injection, drawing and blowing hollow plastic molding machine is high speed, high efficiency, high quality and low energy consumption. High speed means fast running speed, high efficiency means high running efficiency, high quality means high precision and transparency of molded products, and low energy consumption means low energy consumption of molded products. High speed, high efficiency, high quality and low energy consumption is the embodiment of the comprehensive technical level of the host and mold, and is the goal of our further efforts. At present, the cycle operation time of China's injection, drawing and blowing hollow plastic molding machine forms six 0.6L PET bottles in one mold, which is about 601 slower than similar machines in the world. The main motor source of the experimental machine is not bright%, which reduces the production efficiency and increases the energy consumption, regardless of the product quality. The "three stations" do not need to reheat the parison in the blow molding process, so the energy consumption is lower than the "four stations". Japan Aoki solid sbll-50s the first mock examination four cavity three station, the cycle time is only 4S, 8.5s to form four 26.2g bottle mouth diameter of 60mm 0.5L bottles

3.4 wide mouth bottle injection, pull and blow hollow plastic molding machine

at present, the "one-step" injection, pull and blow hollow plastic molding machine developed in China is narrow mouth bottle injection

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