Blunt Tip Metal Cannula Manufacturing for Deep Vial Access
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Solution Overview
Problem
Current medical practices require long cannula assemblies to access vials without disturbing the medicament, but plastic needles are weak and cannot be longer than ½ inch, posing a risk of needle-stick injuries and limitations in accessing vials greater than ½ inch depth.
Innovation Solution
A method of manufacturing a metal cannula with a blunt tip by pressing, cutting, and machining to create segments with pressed edges and side openings, which are then attached to a hub assembly to form a vial access cannula, allowing for extended length and reduced risk of needle-stick injuries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If plastic needles are used, then needle-stick injury risk is reduced, but cannula length is limited to ½ inch due to weakness
Solution Approach 1:
The patent changes the material parameter from plastic to metal, which fundamentally alters the strength and length capabilities of the cannula. This material substitution enables the cannula to achieve lengths greater than ½ inch while maintaining structural integrity, thereby resolving the contradiction between safety (reduced needle-stick risk) and functionality (access to deep vials).
Solution Approach 2:
The patent employs a composite structure combining metal cannula with a hub assembly that includes both plastic and metal components. This composite approach allows the cannula to leverage metal strength for extended length while utilizing plastic components for safety and ease of use, effectively balancing the contradiction between reduced injury risk and increased cannula length.
2Length of moving object
If metal cannula is used, then cannula length can be extended beyond ½ inch, but needle-stick injury risk increases
Solution Approach 1:
The patent applies local quality by creating a blunt tip at the distal end of the metal cannula while maintaining the sharpness and strength of the metal body. This localized modification of the tip geometry allows the cannula to safely access deep vials without increasing needle-stick injury risk, as the blunt tip cannot penetrate skin even if exposed.
Solution Approach 2:
The patent inverts the conventional needle design by using a blunt tip instead of a sharp point. This inversion fundamentally changes the interaction mechanism: rather than relying on sharp penetration, the blunt tip uses controlled deformation and displacement to access vials, thereby eliminating the harmful needle-stick injury risk while maintaining extended length capability.
3Length of moving object
If long cannula assembly is used to access vials, then vial access is enabled, but plastic needles become unreasonably large in diameter
Solution Approach 1:
The patent changes the material parameter from plastic to metal, which fundamentally alters the strength-to-diameter ratio. This material substitution enables the cannula to maintain a reasonable diameter while achieving extended length, as metal provides superior strength that prevents the cannula from becoming unreasonably large in diameter to compensate for length.
Data Source
AI summary
A method of manufacturing a metal cannula is disclosed. The method includes the step of providing a metal cannula having a longitudinal axis and defining a fluid channel. Next, the metal cannula is pressed to substantially close the fluid channel and define a first segment and a second segment. In a next step, the metal cannula is cut to separate the first segment from the second segment of the metal cannula. Each of the first and second segments have a pressed edge. The pressed edge substantially seals the fluid channel and has two pressed corners. Afterwards, each of the pressed corners are cut from the pressed edge of the first segment to define a pair of side openings and a distal blunt edge on the first segment. The side openings are in fluid communication with the fluid channel.