9. Micromachining Using Water Droplets 9.1 Introduction 9.2 Theory of Pulsed Liquid Impact 9.3 Impact by Water Drops 9.4 Modeling Machining Thresholds 9.5 Comparative Results 9.6 Material Removal Rates 9.7 Design of Water-Based Tools 9.8 Analysis of Space Frame 9.9 Mode Shapes of Tetrahedral Structure 9.10 Conclusions 9.11 Problems References