Analysis of the current situation of blow molding

2022-08-15
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Analysis of the current situation of blow molding equipment for medical bottles

medical bottles are one of the largest medical plastic products in terms of production and sales. With the rapid development of the domestic medical industry, the consumption of domestic medical bottles will show a substantial increase. In this regard, domestic hollow equipment manufacturers should take this opportunity to grasp the development trend of plastic medicine bottles, develop new efficient and high-performance medicine bottle molding equipment, and strive to shorten the gap with international advanced technology and equipment

main molding equipment

plastic medicine bottle hollow molding equipment is mainly divided into three types according to different molding methods: extrusion blow molding machine, injection blow molding machine, and extrusion pull blow or injection pull blow molding machine. Extrusion blow molding and injection blow molding machines are mainly used for the production of small and medium-sized plastic bottles for medicine, while extrusion pull blow molding or injection pull blow molding machines are used for the production of large bottles. At present, the largest number of plastic medicine bottle manufacturers apply extrusion blow molding and injection blow molding machines in China. 1 consistency and better print quality

1 Extrusion blow molding machine

the cost of extrusion blow molding machinery (including blow molding mold) is low. For example, when molding the same product, the cost of blow molding machinery is about 1/3 or 1/2 of that of injection molding machinery. At the same time, the production cost of products is also low. Because the parison is formed by the extruder head under low pressure and inflated under low pressure (mostly 0.2~1.0mpa), the residual stress of the product is small, and the resistance to various strains such as tension, impact, bending and environment is high, so it has good service performance. Because the blow mold is only composed of female mold, the wall thickness of the bottle can be changed by simply adjusting the die gap of the machine head or the extrusion conditions. In addition, because the sliding bottom module can be set on the blow mold, the design flexibility of the bottom shape of the bottle body is large. Extrusion blow molding can shape complex, irregular and integral products, so it is more suitable for forming rigid plastic medicine bottles with HDPE and PP raw materials

2. Injection blow molding machine

injection blow molding machine is mainly used to process medical bottles of HDPE and PP raw materials. Small plastic medicine bottles formed by injection blow molding equipment are generally welcomed by pharmaceutical manufacturers. Because the injection nozzle of the equipment can inject plastic into the bottle mouth during the molding process of the injection blow molding bottle body, the accuracy of the bottle mouth is guaranteed. The mandrel blow molding bottle body configured by machinery ensures the dimensional accuracy of the plastic bottle body

injection blow molding pharmaceutical bottles can be processed by a one-step 2-station or 3-station injection blow molding machine. Due to the lack of a dedicated bottle removal and cooling station for the 2-station injection blow molding machine, it is difficult to realize full-automatic counting and packaging, resulting in a production efficiency lower than that of the 3-station. Therefore, in the actual production, the application is more 3-position machine. The three stations of the machine are distributed in equilateral triangle with 120 angles. The first station is injection molding station, the second station is blow molding station, and the third station is bottle removal and cooling station. The three stations can operate with their first-order natural frequency (768.03hz) far greater than the load frequency (2.00hz), with high production efficiency and short cycle. They can be connected with the conveyor belt for automatic counting and packaging, which truly realizes the whole process of pharmaceutical plastic bottle production without human touch, thus ensuring the hygiene and cleanliness of products. The injection blow molding machine cannot mold products with complex shapes, and most of the molded bottles have small volumes (generally 10~300ml). However, due to the high flatness of the bottle mouth and the uniform wall thickness of the bottle, especially the good sealing performance between the bottle mouth and the bottle cap, the injection blow molding bottle can meet the performance requirements of preventing the volatilization of drug gas in the plastic bottle and the penetration of external gas into the bottle, so that this kind of bottle fully meets the special requirements of drug packaging. As early as the Ninth Five-Year Plan period, the State Drug Administration proposed to use injection blow molding to produce high-quality plastic medicine bottles. At present, China has introduced more than 40 injection blow molding pharmaceutical bottle production lines from abroad, with a total production capacity of about 700million/year

3. Note pull blow molding machine

note pull blow molding machine for pet and PP medicine bottles (for liquid medicine filling) is divided into two types: one-step and two-step. The one-step model refers to an efficient equipment that can continuously carry out the processes of injection molding, heating molding, stretching molding, blow molding and demoulding of molded products on the same equipment. According to the forming process, the one-step model is divided into two types of machines: 3 stations (represented by Aoki machine, an old central enterprise located in Zibo City, Shandong enterprise of Aluminum Corporation of Japan) and 4 stations (represented by Japan rijing machine). The main difference between the two is that the 3-station refers to the completion of the injection molding and the heating molding in one process, while the 4-station refers to the completion of the injection molding and the heating molding in two processes. The one-step model will not cause secondary pollution of products, and the product identity is good. Although the price is relatively high, in order to meet the high cleaning requirements of drug bottles, domestic pharmaceutical manufacturers tend to use one-step injection pull blow molding machines in recent years. Therefore, on the basis of digesting and absorbing foreign advanced technology, some domestic equipment manufacturers have stepped up the development of one-step models that can replace foreign equipment, and achieved some results

two-step model refers to that the injection and stretch blow molding processes are carried out separately by two independent machines. Step 1: an ordinary injection molding machine is used to inject the tube blank, and the bottle head (bottle mouth and thread) of the tube blank is formed. Step 2: place the tube blank on the honeycomb heater or automatic circulating heating conveyor belt for heating and temperature regulation, and then move to the bottle blowing process, and stretch blow molding with compressed air. The advantages of the two-step model are flat bottle mouth, good sealing, fast variety development, and low mold cost and price. However, because the injection tube blank and blow molding are carried out step by step, the product identity is poor, and it is easy to transmit pollution, so it is difficult to pass the bacterial test

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