Comparing the Replication Fidelity of Solid Microneedles Using Injection Compression Moulding and Conventional...

Area of Science:

• Materials Science
• Polymer Engineering
• Manufacturing Processes

Background:

• Polymer surfaces are frequently modified with micro- and nano- features via mass replication techniques like injection moulding.
• Microneedle arrays, a key application, utilize microscopic structures for minimally invasive drug and vaccine delivery.

Purpose of the Study:

• To investigate and compare the replication fidelity of solid polycarbonate microneedles produced by injection compression moulding and conventional injection moulding.
• To identify key process parameters influencing replication fidelity in these manufacturing methods.

Main Methods:

• Utilized a full factorial design of experiments for conventional injection moulding.
• Employed injection compression moulding, varying the compression stroke.
• Conducted finite element flow simulations to analyze cavity pressure distribution.

Main Results:

• For injection moulding, volumetric injection rate significantly improved replication fidelity; mould temperature and holding pressure also had positive effects.
• Melt temperature showed insignificant impact on fidelity within the tested range.
• Injection compression moulding with a larger compression stroke yielded superior and more uniform replication fidelity.
• Simulations revealed higher, more evenly distributed cavity pressure in injection compression moulding.

Conclusions:

• Injection compression moulding demonstrates superior performance for achieving high and uniform replication fidelity in polycarbonate microneedle fabrication.
• Process parameter optimization, particularly volumetric injection rate and compression stroke, is crucial for precise micro-feature replication.