The following is the details of production process:
I. Raw Material Preparation
Firstly, plastic raw materials, typically polyethylene (PE) or other plastics suitable for blow molding processes, are prepared. These raw materials are fed into a resin mixer where they are heated to a specific temperature, softening and becoming easier to process. The temperature and time during this process must be strictly controlled to ensure that the raw materials are fully melted without degradation.
II. Parison Formation
The parison is a critical intermediate product in the blow molding process. It can be prepared through an extruder or an injection molder. In extrusion blow molding, the plastic raw materials are heated and melted in an extruder, then extruded through a parison die head to form a tubular parison. In injection blow molding, the molten plastic is injected into a parison injection mold to form a test tube-shaped parison. The quality of the parison is crucial for subsequent blow molding, requiring uniform wall thickness and a smooth, defect-free surface.
III. Blow Molding
Blow molding is the core step of the process. During this stage, the heated parison is transferred into the blow mold. After the mold is closed, compressed air is injected into the parison to expand it against the walls of the mold cavity. The blow pressure and speed must be controlled to ensure that the parison expands evenly and adheres to the mold cavity, resulting in a plastic product with the desired shape and dimensions. Maintaining a certain blow pressure until the plastic piece cools and solidifies is necessary to ensure dimensional stability and surface quality.
IV. Product Cooling
Product cooling is the final step of the blow molding process. During cooling, the blow pressure and mold temperature are gradually reduced to allow the product to cool and solidify. The cooling time depends on factors such as product thickness, material type, and mold design. Once the product is fully cooled and solidified, the mold can be opened to retrieve the product for further processing.
V. Post-Processing
After retrieval, the product may undergo trimming, deburring, cleaning, and other post-processing steps to ensure its appearance quality and surface finish.
