Plastic hollow container production process, equipment and development (3)

Process comparison:

(1) squeeze blowing:

a. Suitable for PVC, PE, PP
b. Molding line depth, affect the appearance and strength c. There are head and tail materials that require more labor and auxiliary equipment for reuse. d. Bottle thread accuracy is poor.

(2) Note blowing:

a. Suitable for PE,PP
b. Not suitable for containers over 300 ml c. Not suitable for flat, shaped containers d. Containers produced by horizontal injection blowers are prone to uneven wall thickness due to gravity

(3) Note pulling blow a. Suitable for PET, PP, PC, PMMA organic glass, etc. b. The high precision of the parison guarantees the precision of the bottle mouth and the thread c. Products without flash, save material, without crusher and mixer d. Product waste rate is very low e. Good impact toughness, rigidity, improved barrier properties, good surface transparency and gloss. f. No mold line, good anti-fall ability

2. development path:

The first stage: Until the late 1970s and early 1980s, a large number of glass containers were used, and PVC, PE plastic bottles were produced using the extrusion blow process.

The second stage: From the late 1980s to the 1990s, more glass containers were still used, but the injection blow process replaced the extrusion blow process with its advanced properties. In order to improve the quality of pharmaceutical packaging containers, the state has focused on supporting a number of state-owned enterprises such as Shanghai Haichang, Wuxi Hongguang, Wuhan Xiamei, Shandong Xinhua, Qinhuangdao Plastics, etc. The introduction of a number of WEATON injection blowers has greatly increased the strength of PE drugs. Bottle market share and quality.

The third segment: In the early 1990s, with the development of injection technology in the country, PET bottles began to enter the pharmaceutical packaging arena, represented by Guangdong Southern Packaging Co., Ltd., and introduced a Faraday blowing device from the Japan Greenwood Solid Research Institute. A large number of PET bottles were produced and successfully delivered PET bottles in southern China. At the same time, due to the environmental impact of the glass production process, the Bureau of Medicine issued a policy that plastic products will be used instead of glass containers.

Until 01 years ago, a pattern was formed: Southern Packaging used plastic PET bottles produced by one-step AQM machines to win most of the southern markets, while Central China, East China, and North China markets still used PE bottles, but some of them used two-step injections. Pull PET (represented by Huang Yanji) PET bottles.

3. Equipment development process:

The rapid development of China's pharmaceutical packaging products in recent years, the increasing demand for plastic packaging containers, plastic packaging container molding equipment is also growing. As the blow molding equipment first injects the bottle mouth during operation to ensure the accuracy of the bottle mouth, and then blows the bottle body, thereby preventing the gas inside from penetrating into the bottle, ensuring that the bottle mouth and the bottle cap have Close performance. China's plastic injection blow-molded hollow container equipment can be produced in small quantities during the "6th Five-Year" and "7th Five-Year" period, but the precision and performance of the equipment itself are not as good as foreign equipment.

At present, the production of this type of equipment requires greater efforts to improve precision and become a truly accurate injection blower. The so-called "precision injection blower" not only refers to the high stability of the equipment in the high-speed and high-pressure molding process, but also requires a high stability in the production of container size fluctuations and quality fluctuations, that is, the size of the production of the various parts of the container. And the geometric shape accuracy is higher, and other indicators such as the appearance of the container and the intrinsic quality of production efficiency can reach a higher level. This paper forecasts the development of injection blowers in China for the current and future period of time as follows:

(1) Hydraulic control system with high sensitivity, high reproducibility and stability.

In the hydraulic system, in order to achieve energy conversion, transmission and control functions, the plunger screw of the precision injection blower is driven by a hydraulic motor and is controlled by a hydraulic system. Injection molding pressure injection speed, plasticizing pressure, etc. Both are controlled and evenly regulated by the mounting system on the control valve of the hydraulic system.

The adjustment of the speed of the blower screw depends on the electronic instrument. The electronic indicator consists of a sensor and a display. According to the difference in the unidirectional pulse, the computer determines the value of the screw speed and displays the value on the display accurately.

(2) It has fine-tuned control performance, excellent and reliable operation, and easy-to-use electronic control system.

Note that the adjustment of the speed of the blower screw depends on the electronic instrument. The electronic indicator consists of a sensor and a display. According to the difference in the unidirectional pulse, the computer determines the value of the screw rotation speed and accurately displays the value on the display.

(3) High-speed and high-pressure injection of parisons can be performed, and the shrinkage of the container can be minimized during blow molding.

Another feature of the precision injection blower is the development of injection pressure high pressure, the purpose of which is to reduce the shrinkage rate after blow molding and increase the density of the container. Due to the high injection pressure and fast injection speed, compared with ordinary injection blower, the mold clamping system has good rigidity, good durability, sufficient injection mold clamping force, and can resist the pressure of high-pressure, high-speed injection of molten plastic. The mold deformation is minimal.

(4) It has an excellent plasticizing device, which can fully plasticize the plastic under uniform temperature, and can measure correctly.

When the melt is injected into the parison mold and begins to be formed into the blow mold, the plunger screw of the inner barrel of the injection blower rotates, so that the feeder transfers the plastic particles loaded into the juice to the front end of the screw and heats the same. Under the effect of plasticizing the material. When the molten material accumulated on the front of the barrel is equal to the set injection volume, a certain thrust is generated on the screw, so that the screw accurately measures the melted part and can appear on the display, thereby ensuring accurate pre-molding amount.

(5) Precision Injection Molded Film, Design and Manufacturing Technology of Blow Mold

The design and manufacture of precision blank molds and blow molds are prerequisites for obtaining precision containers. Therefore, in the design of the parison mold blow molds, the shrinkage rate of the plastic raw materials should be considered, and the factors affecting the accuracy of the mold structure design should be taken into account to minimize these factors. These factors are roughly the size of the raw material shrinkage, the distribution of shrinkage, the size of the injection molding parison and injection port, the mold temperature control pipe and blow mold cooling water distribution, as well as the choice of mold materials.