Blow molding is a manufacturing process that involves inflating a heated plastic tube,known as a parison or preform, inside a mold cavity to create hollow parts. This process is widely used in the production of medical devices due to its ability to produce complex shapes with precise wall thickness control. There are three main types of blow molding techniques used in the medical device industry: extrusion blow molding、injection blow molding、stretch blow molding.

blow molding process for medical devices:

1. Material Selection: The choice of plastic material is critical in medical device manufacturing. Medical-grade plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), and polyethylene terephthalate (PET) are commonly used due to their biocompatibility, sterilizability, and chemical resistance.
2. Extrusion: The blow molding process begins with plastic resin pellets being melted and extruded into a hollow tube or parison. The extrusion process involves heating the plastic resin to a molten state and forcing it through a die to form the desired shape.
3. Mold Design and Preparation: The mold used in blow molding consists of two halves, the male and female molds, which define the shape of the final product. The molds are designed to accommodate the expansion of the plastic material during the blow molding process. They are precision-engineered to ensure accurate dimensions and smooth surface finishes.
4. Mold Clamping: Once the mold is prepared, the parison is placed between the two halves of the mold, and the mold is clamped shut. This ensures that the mold remains securely closed during the subsequent steps.
5. Blow Molding: In this step, compressed air is introduced into the parison, causing it to expand and conform to the shape of the mold cavity. The air pressure is carefully controlled to achieve the desired wall thickness and dimensional accuracy. The plastic material is cooled using a combination of internal and external cooling methods to solidify and retain the shape.
6. Ejection and Trimming: After the part has cooled and solidified, the mold is opened, and the formed part is ejected from the mold cavity. Excess material, known as flash, is trimmed or removed to achieve the final product shape.
7. Post-Processing and Quality Control: The blow-molded medical devices then undergo post-processing steps such as surface treatment, printing, assembly, and quality control inspections to ensure compliance with industry standards and customer requirements.