Brief Analysis of Key Factors in Quality and Design of PET Plastic Preforms
Polyethylene terephthalate (PET), commonly known as polyester. The production of PET plastic bottles can be divided into injection stretch blow molding (ISBM) and extrusion stretch blow molding (ESBM) based on different preform types. Among these two molding methods, the ISBM process is more commonly used due to its easy controllability, high production efficiency, and low scrap rate.
The quality of preforms largely depends on the quality of PET materials. Therefore, it is necessary to select materials that are easy to inflate and form, and formulate a reasonable preform molding process. Experiments show that for PET preforms with the same viscosity, those made from imported raw materials are easier to blow-mold than those made from domestic raw materials. However, preforms from the same batch but with different production dates may require different blow-molding processes. The quality of preforms determines the difficulty of the blow-molding process. Qualified preforms shall meet the requirements of being pure, transparent, free of impurities and color, with an appropriate length of injection point and a halo around the injection area.
Plastic preforms are the initial form in the manufacturing process of plastic bottles. Parameters such as their size, neck finish (mouth diameter), and weight are crucial, as they directly affect the application and performance of the final bottles.
First, the size of preforms is essential for the final packaging container. When determining preform size, the primary consideration is the application of the bottle—whether it is for food, beverages, cosmetics, or other fields. Different applications may require bottles of different shapes and capacities. By carefully considering the product’s capacity requirements, the capacity of the preform can be determined, and a suitable shape (such as round, square, or oval) can be selected.
Second, the neck finish (i.e., the diameter of the bottle mouth) is another key parameter. When measuring the neck finish, it is necessary to ensure the measurement is taken horizontally to obtain an accurate diameter. The size of the neck finish directly affects the filling and pouring efficiency of the bottle. Different products may require neck finishes of different sizes, so rational selection of the neck finish is essential during bottle design.
Finally, the weight of a preform refers to the total weight of the bottle (including the bottle body and neck). The weight can be accurately measured using a weighing method or a spiral scale. The determination of preform weight is directly related to the strength and durability of the final bottle. When setting the weight, a balance must be struck between the bottle’s structural strength and material cost—ensuring the final product has sufficient strength while meeting economic requirements.
In summary, the size, neck finish, and weight of preforms are important considerations in the plastic bottle design stage. Through careful measurement and rational selection of these parameters, the final bottle can meet product requirements and industry standards, providing excellent packaging performance. Continuous attention to the control of these parameters during bottle manufacturing will help produce high-quality plastic bottles.
Guangdong Hongyuan specializes in the production of plastic bottles, plastic pet preforms, and supporting lotion pumps. If you have any needs, please feel free to contact us at any time. As a source factory, we guarantee quality and are trustworthy!
