Micromilling: a method for ultra-rapid prototyping of plastic microfluidic devicesElectronic supplementary information (ESI) available: For information on mill setup and alignment please see ESI, Appendix A. For experimental methods and materials, see ESI, Appendix B. For vapor polishing and addition cell culture images, see ESI, Appendix C. For information on programming the CNC, see ESI, Appendix D. See DOI: 10.1039/c5lc00234f

This tutorial review offers protocols, tips, insight, and considerations for practitioners interested in using micromilling to create microfluidic devices. The objective is to provide a potential user with information to guide them on whether micromilling would fill a specific need within their overall fabrication strategy. Comparisons are made between micromilling and other common fabrication methods for plastics in terms of technical capabilities and cost. The main discussion focuses on "how-to" aspects of micromilling, to enable a user to select proper equipment and tools, and obtain usable microfluidic parts with minimal start-up time and effort. The supplementary information provides more extensive discussion on CNC mill setup, alignment, and programming. We aim to reach an audience with minimal prior experience in milling, but with strong interests in fabrication of microfluidic devices. Micromilling is a fast and simple method capable of fabricating complex 2D or 3D microdevices compatible with cell culture and microscopy.