Syringe Preform Blow Moulding for Small-Diameter Bypass Channels

The patent replaces the mechanical punch-deformation system with a thermal-forming system. Instead of mechanically punching the bypass channel through plastic deformation, the preform is heated to soften the material and then expanded using pressurized gas to form the bypass channel against a mould. This substitution eliminates the insertion difficulty of punches in small-diameter preforms while maintaining the ability to create bypass channels effectively.

The patent changes the physical state parameter of the preform material by heating it to its softening temperature. This parameter change allows the material to become more compliant and formable, enabling the bypass channel to be created through gas expansion rather than mechanical punching. The temperature parameter transformation resolves the contradiction by making the material suitable for forming without requiring forceful punch insertion.

The patent applies heating locally to the specific portion of the preform where the bypass channel needs to be formed, rather than heating the entire preform uniformly. This localized heating minimizes thermal gradients and internal stresses that could cause cracking, while still achieving the necessary softening for precise bypass channel formation in the target area.

The patent uses a mould into which the heated preform portion is expanded. The mould provides a pre-prepared cavity that guides and cushions the deformation process, ensuring the bypass channel forms with correct geometry while distributing stresses uniformly. This beforehand preparation of the mould cavity prevents stress concentration and cracking during the forming process.