Injection Nozzle Sacrificial Tip Machining
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Solution Overview
Problem
Conventional injection molding techniques for needle-free transdermal injection devices often result in nozzles with defects such as flash and voids at the exit orifice, which can interfere with the flow of injectates and reduce the performance of the device.
Innovation Solution
A method involving the formation of a nozzle with a sacrificial tip around the exit orifice, followed by machining to expose the orifice, using techniques like injection molding, machining, or 3D printing, to achieve favorable geometric characteristics and minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional injection molding techniques are used to form nozzles, then the manufacturing process is simple and fast, but defects such as flash and voids occur at the exit orifice
Solution Approach 1:
A sacrificial tip is formed around the exit orifice during the injection molding process before the nozzle is completed. This preliminary structure prevents defects by occupying the space where flash and voids would form, allowing the main nozzle body to be molded without these defects. The sacrificial tip is later removed to expose the clean orifice.
Solution Approach 2:
The sacrificial tip acts as an intermediary element during manufacturing. It is temporarily present to prevent defect formation during injection molding, then removed through machining or other removal processes. This intermediary structure enables the production of high-quality orifices while maintaining efficient injection molding processes.
2Manufacturing precision
If a sacrificial tip is added to the nozzle structure, then manufacturing precision of the orifice is improved, but the device complexity increases
Solution Approach 1:
The sacrificial tip is a temporary component that is deliberately discarded after serving its purpose during manufacturing. It is removed through machining, drilling, or other removal processes, leaving no permanent trace in the final product. This approach allows complex defect prevention without permanent structural complexity.
3Manufacturing precision
If the exit orifice is occluded by a sacrificial tip, then defects are prevented during molding, but additional machining steps are required
Solution Approach 1:
The defective portions (flash and voids) are prevented from forming in the first place by the sacrificial tip. The tip is then extracted or removed through machining processes, revealing the clean orifice. This extraction approach is more efficient than trying to remove defects after they form.
Data Source
AI summary
A material for an injection nozzle is molded into a form that includes a sacrificial tip around the nozzle exit orifice. The sacrificial tip is then machined away using any suitable machining process to expose the exit orifice. In this manner, an injection nozzle can be fabricated with favorable geometric characteristics.