Manufacturing of an array of microneedles in a steel insert for micro-injection moulding using laser milling

The use of arrays of hollow micro needles offers the potential of pain free drug delivery through the skin. However, their batch manufacture represents a real challenge. Especially, it is difficult to design and implement reliable and cost effective manufacturing solutions suitable for scale up production of such new drug delivery devices. In this paper the authors report an investigation of possible manufacturing process chains for producing steel mould inserts for serial replication of microneedles’ patches employing injection moulding. The focus is on manufacturing solutions that utilise nano-second and pico-second laser milling for machining the necessary replication inserts. The process optimisation issues associated with their manufacture are discussed, and the processing windows that were determined are described. To validate the proposed tool-making process chains some moulding inserts were successfully machined using both laser milling technologies. Finally the limitations and uncertainties of these tool making process chains are discussed.