Fabrication and analysis of plastic hypodermic needles.

Plastic hypodermic needles may help reduce illness and disease due to unsterile re-use, as they may be more easily disabled and disposed of as compared to metal ones. This paper presents the fabrication of plastic hypodermic needles using micro-injection moulding and the analyses of their buckling behaviour. As a needle cannula is a thin-walled column (here 0.7 mm outer diameter with a 0.15 mm wall thickness), it is vulnerable to buckling. The buckling behaviour is characterized by numerical simulation and experiments, which are compared to the penetration forces for rubber skin mimic and human skin.